distribution category: energy storage-electrochemical

Distribution Category:Energy Storage-Electrochemical(UC-94c)

ANL-76-12

ARGONNE NATIONAL LABORATORY9700 South Cass Avenue

Argonne, Illinois 60439

COST ESTIMATE FOR THE COMMERCIAL MANUFACTUREOF LITHIUM/IRON SULFIDE CELLS

FOR LOAD-LEVELING

by

W. L. Towle Industrial Participant*J. E. A. Graae Consultant to Battery ProgramA. A. Chilenskas Group Leader, Batter ProgramR. 0. Ivins Assoc. Manager, Battery Program

March 1976

Now

-amin a , w fUvm"- -=

do W* am-- .hrwrrN."+s

*Globe Union, Inc., Milwaukee. Wisconsin.

TABLE OF CONTENTS

ABSTRACT . . . . . . . . . . . . . . . . .

S UARY. . . . . . . . . . . . . . . . . .

I. INTRODUCTION . . . . . . . . . . . .

II. CELL DESIGN BASIS. . . . . . . . . .

A. Modifications of Basic Design.

III. MANUFACTURING COST . . . . . . . . .

IV. EQUIPMENT AND LABOR DETAIL . . . .

A. Functional Classification Index.

B. Details of Manufacturing Steps .

APPENDIX A - DETAIL FLOWSHEET FOR PROCESS.

APPENDIX B - CHANGES FROM PREVIOUS PLAN. .

REFERENCES . . . . . . . . . . . . . . . .

iii

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LIST OF FIGURES

No. Title Page

1. Flowsheet for Process . . . . . . . . . . . . . . . . . . . . . . . 5

2. Cell: Exploded View . . . . . . . . . . . . . . . . . . . . . . . 8

3. Lithium-Sulfur Battery Plant Layout . . . . . . . . . . . . . . . . 14

4. Anode. Exploded View . . . . . . . . . . . . . . . . . . . . . . . 18

5. Cathode. Exploded View . . . . . . . . . . . . . . . . . . . . . . 18

6. Container Walls andlBottom. . . . . . . . . . . . . . . . . . . . . 19

7. Cell Cover Assembly . . . . . . . . . . . . . . . . . . . . . . . . 20

8. Degreaser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9. Anode Assembly (Schematic). . . . . . . . . . . . . . . . . . . . . 26

10. Cathode Assembly (Schematic). . . . . . . . . . . . . . . . . . . . 28

11. Longitudinal Section of Lithium Charger . . . . . . . . . . . . . . 31

12. Cross Section of Lithium Charger. . . . . . . . . . . . . . . . . . 32

13. Loading of Cathode to Lithium Charger . . . . . . . . . . . . . . . 34

14. Typical Lithium Feed System. . . . . . . . . . . . . . . . . . . . 35

15. Preassembled Parts................... . . . . . . 46

16. Station 6 . . .e. . . . . . . . . . . . .. . . . . . . . . . . . 46

17. Station 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

23. Station 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

19. Station 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

20. Station 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

21. Station 6 - Leak Test . . . . . . . . . . . . . . . . . . . . . . . so

22. Station 7 - Blectrical Tests............... . . . . . 51

23. Station 8 - beat to 400'C.............. . . . . . . . 51

24. Cell Neat Rack Detail. . . . . . . . . . 52

25. Station 9 - Salt Fill....... . . . . . . . . . 53

iv

26.

27.

28.

29.

30.

Station 9 - Salt Fill, Detail - - - - - - - - -- . -" - . --

Station 10 - Final Seal . . . . . . . . . . . . . . . . . .

Station 11 - Final Test . ... . . . . . . . .. . . . . . . .

Submodule Case. . . . . . . . . . . . . . . . . . . . . . . .

24-Cell Battery. . . . . . . . . . . . . . . . . . . . . . . . .0

LIST OF TABLES

No. Title

1. Design Specifications for the Li-Al/FeS Prismatic Cell forOff-Peak Energy Storage . . . . . . . . . . . . . . . . . . . .

2. Costs of Materials for Off-Peak Energy Storage Cell andS ubmod u le . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. Summary of Manufacturing Cost . . . . . . . . . . . . . . . .

4. Operating Equipment and Labor . . . . . . . . . . . . . . . .

S. Investment Cost Su mary . . . . . . . . . . . . . . . . . . . . . 0

V

55

56

57

59

61

Page

4

10

11

12

12

1

COST ESTIMATE FOR THE COMMERCIALMANUFACTURE OF LITHIUM/IRON SULFIDE

CELLS FOR LOAD-LEVELING

by

W. L. Towle, J. E. A. Graae,A. A. Chilenekas, and R. 0. Ivins

ABSTRACT

An estimate has been made of the cost of commercial manufac-ture of batteries for load-leveling in utility networks, based onthe Li-Al/FeS system. The battery design chosen is the 0.92 kW-hrcell proposed for the BEST Facility. The manufacturing plant wassized to produce 5000 of such cells per day. These cells areassembled for sale in battery cases or submodules, 24 cells to acase. The plant investment is estimated to be $12,500,000. Aselling price of $29.16 per kW-hr is projected, yielding a 252return on invested capital. An allowance for recycle lithiumyields a net price of $27.33 per kW-hr.

SUMMARY

An estimate has been made of the cost of commercial manufacture ofbatteries for load-leveling in utility networks based on the Li-Al/FeSsystem. The first process selected for this study was based on a dischargedanode (no Li in the Al) and a discharged cathode. The latter is made upinitially as a charged cathode containing an equimolar mixture of Fe and FeS2.It is then charged with lithium electrolytically in a molten salt bath. Thepurpose of this procedure was to minimize the need for inert-atmosphere pro-tection in the handling of lithium. In this it succeeded. The cost of theelectrolysis equipment, however, turned out to be higher than anticipated,suggesting that this may not be the cheapest approach. An alternative method-making a charged negative electrode from pyrometallurgical Li-Al alloy-may beevaluated in the future.

The product design chosen is the 0.92 kW-hr cell proposed for the BESTFacility. A few changes were made in the design in the interest of loweringconstruction and materials costs. A detailed flovsheet was then worked out,in which the conceptualized steps in manufacture were thought through carefully.In developing the flowsheet, a conceptual visualization was made of themachinery necessary to carry out these operations on a highly automated basis.Labor content of the operations was thereby held to a low level. An estimatewas then made of the cost of the operating equipment, based primarily on theauthors' knowledge and experience with machinery of a similar nature. Thelabor requirement was similarly estimated.

The conceptual manufacturing plant is sized to produce 5000 per day ofthe 0.92 kV-hr unit cells. This corresponds approximately to the energystorage capacity produced daily in a typical automotive lead-acid battery

2

plant. Cells are assembled for sale in battery cases, or submodules, 24 cellsto a case. A schedule of materials costs based primarily on up-to-date infor-mation from vendors was drawn up. Labor cost was based on a $6 per hour rateplus 302 for the cost of fringe benefits. Supervision, indirect labor, andindirect operating costs (e.g., power) were assumed to be 200% of direct labor.Depreciation was taken on a straight-line basis. To the sum of the above($3.70/kW-hr for labor and overhead) were added the basic materials cost($19.02/kW-hr) and a 5% allowance for plant materials losses ($0.95/kW-hr).The above sum represents factory cost, to which was then added 11% for generaland administrative costs, plus an additional 11% for profit. The total is$29.16/kW-hr, yielding a return of just over 25% on the total plant investmentof $12,500,000.

Where a recycle salvage allowance is justified, a 25% credit has beenestimated based on the Li plus LiCl values in the basic materials cost. Theamount of this credit is $1.83, bringing the net selling price to $27.33/kW-hr.

The result of primary significance is the low cost of labor and overheadin relation to the materials cost. Secondly, the overall price is in thesame range as that of the lead-acid battery. Thirdly, the factory operationsin the conceptual plant are likely to be very similar to those for theconstruction of other molten salt batteries. It is quite conceivable thatother molten salt batteries with lower materials costs may be developed which'ill have equivalent manufacturing costs and thus be significantly cheaperoverall.

It must be stated emphatically that automated manufacturing operations ofthe type upon which this report is based are highly sophisticated. An extensiveand expensive program of development engineering will be required to bring afactory of this type into being. Needless to say, the cost per unit productfor a pilot plant will be much higher than for the manufacturing plant describedhere. Indeed, even the cost of the first full-scale plant will be considerablyhigher, because it will represent the first application of much of the engi-neering work. The costs given here should be taken as representative of thesecond or third plant.

3

I. INTRODUCTION

The purpose of the work described here was to develop an estimate ofcommercial manufacturing cost for a cell of the type to be used in the BatteryEnergy Storage Te at (BEST) Facility. The cell design used as the basis forthe study is a v' ,(c-1 prismatic type having a central positive plate andtwo facing negate, 1;'es. The cell is described in ANL-75-1. 1 Specificationsare given in Tabli 1. +e present study is intended primarily to improve ourappraisal of the ems.: K viability of the overall program. By definingspecific requirements in the manufacturing operations, it will also help toorient R & D efforts along the most productive lines. Lastly, since it wasnecessary to develop a rather clear-cut methodology for the manufacturingoperations, the concepts reported here may prove to have value as a basis forfuture engineering work.

The flowsheet chosen for study (a detailed flowsheet is given in AppendixA) involves the production of a discharged negative electrode made with alu-minum powder in a steel wool plaque (see Fig. 1). The discharged positiveelectrode is first made up as a charged positive electrode. This is thenconverted to the discharged state by electrochemical loading with lithium,forming Li2S. The purpose of this method was to avoid - or at least minimize- the need for an inert atmosphere in handling lithium, in the belief that aprocess with minimum need for an inert atmosphere would be less costly thanothers. However, the requirements for this electrochemical operation weredetermined to be more complicated and expensive than anticipated. Otherapproaches - such as making a charged negative electrode from pyrometallurgi-cal Li-Al alloy - may therefore be cheaper and may be evaluated in thefuture.

We plan to make the positive electrode from an equimolar mixture of FeS2and Fe powders. Other deviations from the basic cell design are discussedlater in this report. The changes were made either to reduce materials costor to simplify fabrication.

The estimates of equipment cost given here are for the most part basedon the experience of the authors. In the interest of arriving expeditiouslyat r round-number appraisal of overall cost as a function of the chosen flow-sheet, it was decided that more exact pricing of equipment should be postponeduntil the choices were further narrowed.

Likewise, labor requirements were estimated based on the authors' exper-ience with similar operations in other manufacturing plants. No attempt wasmade at this point to develop actual time study data.

The size of the plant (5000 cells/day of 0.92 kW-hr each) was chosenbecause of the similarity of its capacity to that of a typical automotivelead-acid battery plant (5000 batteries/day of 0.6 to 1.1 kW-hr each). Asingle assembly line in our plant was targeted to turn out two cells a minute.Two-shift operation of most plant equipment is planned. Operated continuously,each assembly line would produce

2 cells x 60 x 8 hr x 2 shifts " 1920 cells/daysin

4

TABLE 1. Design Specifications for the Li-Al/FeS PrismaticCell for Off-Peak Energy Storages

Cell DescriptionDimensions

HeightWidthThicknessWeight

Average VoltageCapacity

TheoreticalAt 802 Utilization

EnergySpecific EnergyOperating Temp.

Negative PlateReactantNumber of PlatesLength and WidthThicknessElectrolyte Vol. FractionArea of One SurfaceWeight of Li-AlVolume of Two Plates

Positive PlateReactantNumber of PlatesLength and WidthThicknessElectrolyte Vol. FractionArea of One SurfaceWeight of FeSVolume of Plate

SeparatorMaterialNumber of SeparatorsThicknessWeight of SN

31.131.12.5

"6.21.15

cacmcakgV

1000 A-hr800 A-hr920 V-hr150 -hr/kg400-450"C

Li-Alb2

30.8 ca0.523 co0.25

948 ca2

1266 g992 cm 3

FeS1

30.51.0640.55

9301642

99,

N2

0.076"'34

cmcm

cm2

Cell Power and Specific PowerDischarge (at 10-hr Rate)

PowerSpecific Power

Cell Current and Current DensityDischarge (at 10-hr Rate)

CurrentCurrent Density

Charge (at 5-hr Rate)CurrentCurrent Density

Capacity per Unit VoluesNegative ElectrodePositive Electrode

Power per Unit Area of ElectrodeDischarge (at 10-hr Rate)

Call Coonsn t Ne_tLi-AlbFeSLiC1-KC1Current Collectors

and StructureSeparator and

Particle RetainerFeedthroughHousing

Total

92 V1 5 V/kg

%74 A0.043 A/cm2

%144 A0.086 A/cm2

0.81 A-hr/cm 3

0.81 A-hr/ca3

0.099 W/cM2

ofV.a Tutal

1226 201642 261387 22

909

75100844

6183

IS

12

_14

100

cmg

aterialsCurrent Collector

Negative ElectrodePositive Electrode

HousingParticle Retainer

Fe or NiFeFe

Zr02

*Tentativw; to be optimised by system and cost studies (from ANL-7S-1).s0 at. -Al.

SANParAfecdeo

cI

pa 9/tEcItrochemeal

prtrtrr~ Astiembit Charge of-- ---- CathodL- Assend y

AAenCf- sMiblen

SeranFaric~e

an" Cot Battery CaseS Parts and Connector

Cortainer

lubem Production

%fg-Tumn Cme

Electroyte

Fill

Sealingof Celis

Tests

SubmoduleS Assembly

FinalTests

Strip -

Fig. 1. Flovaheet for Process

%A

I

6

Three Assembly lines would produce 5760 cells/day. This allows 5000 cells/dayto be produced if operating efficiency is 5000/5760 - 87%, or 7 hours of opera-tion out of every 8-hour shift. This is a reasonable allowance for work breaks,downtime for maintenance, etc.

Some comments are in order with respect to materials cost. Scrap factorswere roughly estimated for such items as sheet steel and rods. An allowancefor plant losses due to nonconforming product was made by adding 5% to materialscost calculated on a 100% yield basis. It is assumed that salvageable valuesin such nonconforming product will be utilized, and that this 5% will representa net figure.

Since salvage of lithium values should be feasible from over-age unitswhich have failed in the field, a rough estimate of the effect of recycle onnet cost has also been made.

Lastly, it is to be emphasized that the plant cost figures developed heredo not include che cost of any developmental engineering. The automatic ma-chinery which will be required to perform many of the operations describedwill be quite sophisticated, requiring years of development work. The firstmanufacturing plant will require substantial design engineering. Changes inmachine design and plant layout may be required. The second plant to bebuilt will have the benefit of this background of experience. It is to asecond or subsequent plant that the cost figures developed here will apply.

Some of the material used in the preparation of this report had beenpresented earlier in calculating cost projections in a paper presented at theIEEE Southeastcon 75 in April, 1975. In preparing the present paper, somechanges were made in those cost projections. Comparisons are noted inAppendix B.

7

?I. CELL DESIGN BASIS

The cell design used as the basis for this study is the prismatic FeStype suggested for use in the BEST Facility (see Table 1). In this cell,anode and cathode materials-are stoichiometrically balanced. A few of thedesign characteristics are as follows:

Theoretical capacity - 1000 amp-hr

Rated capacity " 800 amp-hr

Avg cell voltage - 1.15 V

Rated cell energy " 920 W-hr

Materials content

Li 259 g

Al 1007 g

FeS 1642 g

External dimensions:(excluding feedthroughs) " 31.1 x 31.1 x 2.5 cm

" 12.25 x 12.25 x 0.985 in.

In order to reduce materials cost and to improve adaptability toautomated manufacturing techniques, some changes were made in the specifica-tions given in Table 1 and in some items not noted in Table 1. These changesare sumearized below.

A. Modifications of Basic Design

The following changes have been assumed:

1. A mixture of FeS2 and Fe will be used in place of FeS.

2. Cu2S is mixed with the cathode material in an amount equal to23 wt Z.

3. Atomized aluminum will be used in place of demister wire.

4. Steel wool will be used as the electrode plaque material, bothfor anodes and cathodes.

5. To permit face-up loading of the anode plaque to the anode frameand of the powder to the plaque,

a. the retaining lip was eliminated from the frame

b. an outer frame preassembled with a coarse retaining screen(applied after powder addition) was substituted for thisretaining lip

c. the top of the frame was closed to assist in retainingpowder and to improve stiffness

d. the current lead tab is now a separate piece, welded tothe back of the frame.

8

6. To permit face-up loading of the cathode powders to both cathodeplaques,

a. the availability of a BN paper separator with a dished ortub-shaped contour was assumed

b. assembly of the cathode components will be done in succes-sion (as shown in Fig. 10).

7. To reduce the welding required in making the cell container,the container will be cut from seamless tubing waged to theappropriate dimensions.

8. To simplify handling of the assembled cells on conveyers, thefill pipe and vacuum pipe will both be attached to the cove-.

9. It is assumed that the BN paper will serve both as an electricalinsulator and a particle barrier, thus eliminating the need forZr02 paper and/or fine-mesh screen. The screens that are shownboth for anwde and cathode are of coarse mesh and serve astructural function only. Possibly, one can be eliminated.

An exploded view of the cell is shown in Fig. 2.

It should be pointed out that not all of the effects of one changewere incorporated in this study. At the time of this study the use of Cu2Sas an additive was in its early exploratory stage. The mechanism of itsperformance and its effect on electrochemical yield were uncertain. For thisstudy, therefore, the cost of Cu2S was added in, but no change was made inthe assumed values for FeS content of the cell or of its electrochemical yield.

M sp 4 wua.

Fig. 2. Cell: Exploded View

means (ataC u eubas

1

a s

9

III. MANUFACTURING COST

Table 2 shows materials costs for the cell and submodule. The costsshown are on the basis of one kilowatt-hour of energy storage capacity. Thefigures in parentheses are the latest prices per unit of materials, as ofJanuary, 1975. With few exceptions, these costs were based either on firmquotations or on vendors' estimates of future selling prices based on advancedtechnology (e.g., for BN paper) or major volume increases, or both.

With the exception of scrap factors for such items as steel sheet androds, no allowance is made in Table 2 for material losses (such as noncon-forming product). Some such losses are bound to occur, although they canbe offset in part by a repair and recovery program. An allowance for thenet effect of such losses is made in Table 3 by adding 52 to the cost of rawmaterials.

Table 4 sumarizes the plant operating equipment, the annual cost ofoperating each equipment category, and the labor requirement.

Table 5 is an investment cost sumary. In addition to the directoperating equipment, a number of specific facilities are itemized. Thelargest of these is the dry room which has a cost of $258,000. (See SectionIV.B.11, Buildings and Services, for details on the estimation of its cost.)A contingency allowance of 152 of total equipment cost has been made. Theestimated life of each equipment item is shown. Depreciation has been figuredon a straight line basis. What is believed to be a rather generous allowancehas been made for lard, buildings, and installation-2002 of the cost ofoperating equipment. Inventory and work in progress has been allowed 202 ofthe cost of equipment, land, and buildings which corresponds to approximatelyone month's supply of raw or converted materials. This has been kept smallin the belief that for the type of market to be served by this plant, a smallinventory of finished goods will suffice. Other cash requirements have beenestimated to be $1,000,000 or roughly 82 of the total.

In the sumary of manufacturing costs (Table 3), the category labor andoverhead was calculated on an annual basis. The estimate of direct laborwas calculated assuming a $6 per hour rate. Fringe benefits were assumed tobe 302 of direct labor. Other indirect labor costs (supervision, clerical,maintenance, etc.) and operating costs (fuel, power, etc.) were assumed tobe twice the direct labor cost. The total annual depreciation of equipmentand buildings was added to the labor cost to arrive at a total for laborand overhead. The factory cost was calculated on the basis of a single k-hrof battery storage capacity, by dividing annual labor, overhead, and materialcosts by the annual plant capacity.

General and administrative costs were assumed to be 112 of the factorycost. This factor includes administrative, sales and distribution costs.Profit before taxes was assumed to be 112 of the sum of the factory cost andthe general and administrative costs. This allows about a 252 return on capi-tal investsnt before taxes. An estimated selling price of $29.16/kW-hr forsubmdules was thus obtained.

It was the purpose of this work to estimate product cost as a measure ofthe investment required by an electric utility for an energy storage unit. No

Table 2. Costs of Materials for Off-Peak Ehergy Storage Cell and Subiodule

$/kM-hr ($/Unit)Material Laboratory Scale Pilot Plant Scalc (BEST) Manufacturing Plant

EletrolyteLicd

active Electrode

Lithiin

SS MireSteel olISeonScram

hwitive ElectrodsFels-

Stee l1ool

smrtots

m clothM Paper

CU st

Steel shr tSteel ESdreedtrg

totaltl (cell.)

9 ole CtmoeSI t"

SSaheetC torsFted sr

574.00 ($117/lb)-a

7.83 ($12.60/ib)15.20 ($6.30/Ib)2.76 ($11.40/ib)

8.31 ($3.85/ft 2 )

217.00 ($55/Ib)123.50 (136/ib)51.50 ($115/bd ft)

5.16 ($1.90/ft 2 )1006.00 ($400/ft2)

2.92 ($65/cwt)0.12 ($74/cwt)27.50 ($24.40 ea)

$2127.90

12.13 ($3.00/ib)-- a

6.36 ($10.25/b)1.21 ($u.50/1b)

0.42 ($1.0O/1b2.67 ($1.24/f t )

0.35b

0.53 ($0.58/lb)

0.36 ($1.00/ib)

81.50 ($30/ft 2 )

1.570 ''

22.AG

$129.29

1.600.545.43

$136.86

($35/cvt)($56/cwt)($20.33 ea)

2.49 ($1.13/ib)0.27 ($0.10/ib)

4.81 ($7.75/lb)1.21 ($0.50/ib)

0.42 ($1.00/lb1.08 ($0.50/f t )

0.35b

0.53 ($0.58/ib)

0.36 ($1.00/ib)

0

2.72 ($1.00/ft2 )

1.480.091.08

$16.89

1.410.540.18

$19.02

($2.50/ft 2 )($0.80/ib)($30.00 ea)

($33/cwt)($54/cwt)($1.00 ea)C

($2.50/fr 2 )($0.80/ib)($4.00 ea)C

a lelmid .. cost of Lid.b kued m e5S2 at i. O5/1b and iron powder at $0.18/lb.c Cost coal for nee-produced unit.

11

Table 3. Suimwary of Manufacturing Cost

Labor and Overhead Cost (Basis: Annual)

Direct LaborOverhead

Fringe Benefits (301)Supervision, Indirect Labor,and Indirect Operating Costs(2 x Direct Labor)

Depreciation

Total Labor and Overhead

Factory Cost (Basis: 1 kWh-hr)

Labor and OverheadMaterialsMaterial Losses, 5% of Materials

Total Factory Cost

Battery Price (Basis: 1 kM-hr)

Factory CostGeneral and Administrative, 112

Subtotal

Profit, 112

Battery Price

$1,080,000

324,000

2,160,000692,000

$4,256,000

$ 3.7019.020.95

$ 23.67

$ 23.672.60

$ 26.27

2089

$ 29.16,

Where appropriate, credit for recycle ofa net figure of $27.33/kU-hr (see text).

lithiui values would give

allowance has bees made in the above cost estimate for the salvage valueof over-age units which have failed in the field. It is reasonable toexpect that the lithium (both metal and salt) would have value. Thetotal initial cost of these materials i ;'.30/kv-br. If it is assumdthat salvage value is 251 of the original cost, a credit of $1.83/kM-hrwould result. A net selling price of a battery based on reibursementfor recycled materials would then be $29.16 - $1.83, or $27.33.

s

12

Table 4. Operating Equipment and Labor

Annual Cost LaborEquipment Category (thousands of dollars) (man-days/day)

FeS2 and Fe PowderPretreatment 46 4

Salt Purification 25 3

Fabrication of Parts 435 10

Degreaser 25 2

Assembly of Anode 360 10

Assembly of Cathode 330 10

Electrochem. Formation 600 6

Assembly of Main Cell 520 20

Assembly of Subsodule 75 11

Utility Men 14

Operating Equipment , Total 241.6

Direct Labor, Total 90

Table 5. Invest.

Cost(thousands of dollars)

Operating Equip tnt 2416Dry Roam 2582 Air Compressors 20Maintenance and Shop 20Office Furniture 14Lockers 16QC Laboratory 3Floor Scrubber 54 Forklift Trucks 32

Subtotal 2786

Cotingency (152) 418

s t Cost Saiiry

et. Life

(yr)(I

151020102015

8-s

Annual Depreciationthousandsa of dollars)

302182111

14

330

42

Total lquipnt

Land, buildings, andInstallation, 2002

Subtotal

inventory and Work inProgress 202

Other r Cash Requirints

Total

3204

6400

9612

1922

1000

12,534

372

320

692

0

13

IV. EQUIPMENT AND LABOR DETAIL

A. Functional Classification Index

The following code is suggested as a basic (but expandable) index ofmanufacturing plant operations. It is used to identify the operating areasas shown in the Plant Layout, Fig. 3, and throughout this report.

1.0 Raw Materials Pretreatment

1.1 FeS2 pretreatment

1.1.1 drying

1.1.1 grinding

1.1.. screening

1.1.4 tabling

1.2 Fe powder pretreatment

1.3 Salt purification

2.0 Parts Fabrication

2.1 Stamping and lending

2.2 Screen and Frame Assembly

2.3 Cell container, cut and weld

2.3.1 cut container body

2.3.2 weld bottom to body

2.4 Brase Fittings to Container Cover

3.0 Electrode Plaques (Positive and Negative)

4.0 Degreasing

5.0 Electrode Asseobly

5.1 Electrode assembly, negative (Anode)

5.2 Electrode assembly, positive (Cathode)

6.0 Electrochemical Charging, Positive Electrodes

7.0 Cell Assembly

8.0 Suboodule

8.1 Case fabrication

5.2 Assbly

9.0 Materials handling and Storage

10.0 Shipping

11.0 Buildings and Services

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10~~ WCefll A~w-bv

rl3 -~-----------1- I I I I I I

1 1 1 1 1 1 1

Drg AL Aro, foun0M1

I Ir"'I.Co "%

&#t 4ledI%'

tIe#tnctw.

Fig. 3. Lithium-Sulfur Battery Plant Layout.Products of Discharged Battery

Anr

1

i

0

yore4ir2f i

Ctr.t,cr

)-26.15I

Iirettrll'os.-II

Shppnq

IOtt

S._

i IfeSWI Iff"aI

tall !'NIt llfl r Tttif1

WOO Cft" Suwtasuie Awtmt 4M IN alr

Ella tir

W Gl

CMIQW U so

15

B. Details of Manufacturing Steps

1.0 Raw Materials Pretreatment

It is ass'txed that the Cu2S will be used as received.

FeS? Pretreatment (1.1)

Choice of Method. The FeS2 technical grade material contains Si02which must be removed. The method consists of grinding, screening, andtabling, utilizing a Wilf ley table (or tables).2

Other methods such as elutriation, jigging, or settling were judgednot applicable because of cost or because they appeared not to be feasible.

Drying. Grinding (1.1.1 and 1.1.2)

It is assumed that FeS2 precrushed to 1/4-in max. size can bepurchased. It will first be dried in a rotary drier. The material will thenbe fed to one or more crushers. Roller mills might be suitable because theyproduce less fines than do other types of grinders. Several roller mills inseries would be required because of the relatively low reduction ratio obtainedwith these machines. The objective is to obtain a powder of fairly uniformgrain size and sufficiently small to provide good liberation of the Si02 fromthe FeS 2 .

Screen ing (1.1. 3)

From the roller mills, the powder is conveyed to the screen, whereall particles larger than 40 mesh are separated and returned to the rollermills.

Tablin (1.1.4)

The screened powder is then fed to one or more Wilfley tables. Theseare shaking tables that separate the particles into bands of particles ofdifferent densities, which leave the table at different points. The concen-trate (FeS 2 ) is sent for interim storage. The tailings (8i02 ) are discarded,and the middlings might either be returned to the grinding operation andrecycled or be discarded.

All of the equipment is commercially available.

aaineerina Calculations

Required amount of FeS2

Bach cathode requires 3.62 lb (1642 g) of FeS2 + Fe (forming 2 FeS).Of this, 2.47 lb is FeS2

5000 x 2.47 " 12.300 lb/day

2 shifts (8 hr/shift)

1 770 lb/hr16

16

Specific gravity of SiO2 - 2.65

Specific gravity of FeS2 - 5.00

This density difference should make the separation feasible.

Cost of Equipment

1 rotary dryer $ 8,0003 roller mills with drives 9,0001 screen with drive 3,0003 Wilfley tables with drives 11,000

Equipment cost, total $31,000

Labor Requirement

man-days/day

One man per shift (2 shifts) 2

Fe Powder Pretreatment (1.2)

Choice of Method. The iron powder which we buy is expected to havea superficial surface layer of oxide. We plan to remove this oxide by passingthe powder at high temperature through a strongly reducing atmosphere. Asmall rotary furnace could be used for the operation. Alternatively, afluidized bed might be used. To prevent reoxidation, it will be necessary tocool the product against the stream of dry incoming gas fuel.

Engineering Calculations

Quantity of iron to be treated:

1642 Fes x=1 1 Fe -55.8 x500Cellscell 4 5 4 x2 xFeS =87.9 x 5000 day 5740 lb/day

Cost of Equipment

Rotary furnace $15,000

Labor Requirement

can-days/day

Assume 1 operator per shift (2 shifts) 2

This man should have time available toassist the operator in the FeS2 pretreat-ment area, who has more equipment tooperate.

17

Salt Purification (1.3)

Choice of Method. Two methods of purification of the LiCl-KC1 saltwere considered: drying in a fluidized bed and electrolysis. The lattermethod was selected. It appears to be the less complex (a fluidized bed wouldrequire the presence of HC1 or C12 to retard hydrolysis). Also, electrolysiswill remove trace impurities. We visualize three cells operated in series,both as to flow of salt and flow of current, three shifts per day. A smallproportion of the LiCl would be electrolyzed in each cell (a total of 1-5%in the three cells). This would allow skimming off of any of the more-easily-decomposed impurities. Moisture present in the initial salt would causehydrolysis to LiOH, which has a lower decomposition potential than does LiCl.Salt prepared in this manner (samples frgm working cells producing metalliclithium) has been obtained from Lithcoa. It showed only a couple of minorwaves when examined by electrolytic scanning technique; this indicates goodquality according to Dr. R. K. Steunenberg.


Salt required/day - 2045 g/cell x55 22,600 lb/day

Consisting of: 920 g LiCl/cell corresponding to 10,200 lb/day

1125 g KC1/cell corresponding to 12,400 lb/day

Electrolytic purification was assumed using two (or three) cellsin series, sacrificing %5% (max) of the incoming LiCl, and using gas-heatedpots, with current passed continuously.

Current to be passed:

10,200 x 0.05 x 454 x 26.8 amp-hr -"145,500 amp-hr42.4 g-mol day

145,500 x 24 6,060 amp

6060 amp x 4 V - 24,200 W

If 12 electrolysis is sufficient (instead of 52, above), purificationwill require 1,200 amp, corresponding to 4,800 W.

Cost of Equipment

Rectifiers, etc. $10,000Cells, ducting, gas supply 10,000Piping 2,000Misc. 3,000

$25,000

*Lithium Corporation of America, Gastonia, North Carolina.

**Group Leader, Cell Chemistry, Battery Program, Chemical engineering Division,ANL.

18

Labor Requirement

man-days/day

Assume 1 man per shift (3 shifts) 3

2.0 Parts Fabrication

Choice of Method. Provision must be made for the fabrication ofelectrode frames, current collectors (cathode only), and cell containers(see Fig. 4 and 5). For the electrode frames, we will buy sheet steel,probably in coils. It will be set up to reel automatically into a stampingdie where it will be cut. Bending to shape will be accomplished as part ofthe same stroke by the machine. Since there will be several types of work,some allowance will be made for the time to change dies. A rate of 60strokes/min is assumed. At this production rate, two machines will beneeded. One operator is required for each machine.

The screens will be fastened to the electrode frames by stapling.Automatically operating machines are planned. All that the operator mustdo is keep the machines supplied with feed materials and transfer the productto pallets. Three stapling machines will be needed, and one operator cantend all three.

Positive electrode current collectors will be stamped to size onthe stamping machines described above.

Material for cell containers will be purchased as seamless rectan-gular tubing. The tubing will be loaded into a machine which will positionit automatically and cut it to length (for example, with a "shimmy die" cutter).After they are cut, the container walls are degreased. They then are transportedto a welder, where they are welded automatically to cell bottoms. The latterare stamped and bent on the same machine as is used for shaping the electrodeframes. An exploded view of the open-topped container is seen in Fig. 6.After automatic welding, the open-topped containers are placed on pallets forlater use in the cell assembly area. One cutting machine and three weldingmachines are required. One operator can tend all of these machines, pro-vided he has help in getting the parts to and from the degreaser. This helpcould be provided by one of the utility men.

I - - 1 I * Sc-al

lop Feweme em a.r -eu

S ma s) --- - - *ku a we

r s s am u kssar_ j=ha, haws ~-

fale _% J FAM " $ a

Fig. 4. Fig. S.Anode. Exploded View Cathode. Exploded View

19

CA IAINWEMALLS

I

T siDows

hut om- 5owt

Fig. 6. Container Walls and Bottom

Assembly of the fittings to the cell covers (Fig. 7) is the last ofthese preliminary operations. The cell covers (which are stamped and benton the same stamping machine as is uoed for shaping the cell bottoms) areplaced by the operator in the assembly machine, along with the followingparts: positive electrode feedthrough (lower portion), negative terminal,salt-fill tube, and evacuation tube. (It is assumed here that these partsare purchased ready to use.) A machine for attaching fittings to a coverwill position the cover, feed the parts to their appropriate positions, andbraze them by induct ion heating. Three of these machines are required. Oneoperator can tend all three.

The number of cell pieces to be handled dailyare shown in the following tabulation:

in these operations

Braze

Stamp Stamp & Seal FittingsOnly Bend Staple Cut Weld to cover

Base trame, anode 10,000Top frame, anode 10,000 10,000Screen, anode 10,000 10,000Frame, cathode 10,000 10,000Screen, cathode 10,000 10,000Current Collector, Cathod: 5,000Cell Container, walls 5,000 5,000Cell Container, bottom 5,000 5,000Cell Container, cover 5,000 5,000Submodule, cover & bottom 416a,Number of machines reqd. 3 1 3 3

(two-shift operate ion)

a dend only.

i.

i

L- I

20

FITTINGS

COVER

Fig. 7. Cell Cover Assembly

FIXTURE 1. Position the Cover on the Fixture2. Drop the Fittings in Place

3. Add Braze4. Lower the Induction Heaters and Braze

the Fittings to the Cover- K K ET OINDUCTION 5. Remove the Completed Cover

EATENRS

As stated above, bending will be done on the same machine as stamping.Note also that the cell container bottoms and covers are to be stamped and benton the same machine.


Stamping and Bending (2.1)

Total parts to be handled - 70,416/day

Estimated rate of machine operation " 60/min

70,4160 - 19.5 machine-hr

To allow for die changing from one job type to another, two machinesand two shifts would be used (thus providing 2 x 14 - 28 machine-hr).

Screen and Frame Assembly (2.2)

Total parts to be produced - 20,000/day

Estimated rate of machine operation - 10/min

209000 33.3 hr10 x 60

Working time/shift a 7 hr

Working time/2 shifts - 14 hr

- 2.35 machines needed

Use threo machines

21

Cell Container Cut and Weld (2.3)

Cut Container Body (2.3.1). Parts to be produced - 5000/day. Assumethat 10 containers can be cut from one tube. Allow 30 sec for setup for eachtube. Assume one cut every 3 sec. This results in the production of 10/min.Machines required -a -00 - 0.595

10 x 60 x 14

Plan to use one machine.

Seal Weld Container Bottom to Body (2.3.2). Parts to be produced- 5000/day; 26 in. of weld/cell. Assume a welding speed .of 1 in./sec per torch.If two torches are used, the welding time is 26 ' 2 or 13 sec/cell. Ifwork is on a 30-sec cycle, this allows 17 sec for positioning of the work,which is ample.

30600 x5000hcells - 2.96 machines required. Use three machines.

Braze the Fittings to the Assembly Cover (2.4)

Parts to be produced - 5000/day. A 30-sec cycle is visualized, andthree machines would be required.

Cost of Equipment


Two machines @ $50,000

Tooling

Anode frames

Anode screens

Cathode frames

Cathode screens

Current collector

Container bottoms

Container tops

Submodule, covers + bottoms

Total, stamping and bending

-1

-1

-1

-1

-1

-1

-1

- 1

set/machine

set/machine

set/machine

set/machine

set/machine

set/machine

set/machine

set

Assemble and Staple (2.2)

Three machines @ $25,000

Cell Container, Cut and Weld (2.3)

Cut: One machine @ $25,000

Weld to bottoms: Three machines @ $30,000

Total, container walls, cut and weld

@$5000

@ 3000

@ 5000

@ 3000

@ 3000

@ 3000

@ 3000

@ 5000

$100,000

10,000

6,000

10,000

6,000

6,000

6,000

6,000

5,000

$155,000

75,000

25,000

90,000

$115,000

22

Braze Fittings to Container Cover (2.4)

Three machines @ $30,000 $ 90,000Total Equipment Cost, Parts Fabrication $435,000

Labor Requirement

man-days/day


1 operator for 1 machine (2 machines, 2 shift,,) 4

Screen and Frame Assembly (2.2)

1 operator for 3 machines (2 shifts) 2

Cell Container, Cat and Weld (2.3)

1 operator (2 shifts) 2

Braze Fittings to Container Cover (2.4)

1 operator for 3 machines (2 shifts) 2

Plus 2 men to feed degreaser (2 shifts) 4

3.0 Electrode Plaques

It is assumed that the supplier of the plaque material will furnishit in precut sheets of steel wool, compressed to the desired thickness ndporosity.

The plaques are sent through a degreaser before being sent to eitherthe anode or cathode assembly. There they are placed in feedracks whichautomatically feed them to the electrode assembly operation. The plaques forthe negative and positive electrodes, which differ only in the thickness ofthe material, are handled in the same way.

Cost of Equipment

The degreasing equipment is used also for many parts other than the

plaques. The cost of this equipment is discussed in Section 4.0, Degreasing.

Labor Requirement

Discussed in Section 4.0, Degreasing.

Identifiable Problems to be Resolved

Possibly, special modification of the plaques will be needed toobtain satisfactory current collection throughout the electrode during dischargeof a cell. Such steps might consist of adding rivets or other physical means

23

of improving contact of the active powders, the plaques, and the currentcollectors.

The decision to have the vendor cut the plaques to size was basedon the assumptions that he would be able to do it cheaper and that he wouldbe better able to control the thickness and porosity of the product. Bothof these assumptions should be reviewed as more information becomes available.

4.0 Degreasing

Choice of Method. A continuous degreasing unit (Fig. 8) is proposed.All cell parts will pass through it. It will be of the ref luxing chlorinatedsolvent type and will consist of a long trough from which solvent will beboiled. Baskets containing the parts will be carried through the solventvapors, which will condense on the cold parts and drain back into the trough.A transducer (such as a thermocouple or thermistor) located above the levelof the baskets (but within the walls of the trough) will sense the level ofthe vapors and send control signal to the heat source. This will allow thevapors to be held at the proper level. A trough 15 ft in length will allowa 5-min residence times for parts. At the downstream end, the parts will passthrough a drying oven. Provisions for stripping the air of solvent vaporsmay be necessary.

Degreasing of the tubing to be fabricated into cell containers is aspecial situation. The tubing should be degreased after it is cut to lengthand before it is welded. It is believed that the other cell parts can bedegreased immediately before electrode fabrication.

Engineer ing Calculat ions

Major parts to be degreased (basis, 1 day):

Anode bottom frameAnode top frameAnode plaqueAnode screenCathode bottom frameCathode bottom screenCathode plaque, lowerCathode current collectorCathode plaque, upperCathode top screenCathode top frameCell container walls (tubes)Cell bottomsCell covers

Total major parts

10,00010,00010,00010,0005,0005,0005,0005,0005,0005,0005,0005,0005,0005,0(0

90,000

Total major parts/cell s 000

Avg thickness of parts " is 0.193 in.

Size of baskets for carrying parts " 15 in.

Approx. Thicknessper cell (in.)2 x 0.25 0.502 x 0.15 0.302 x 0.25 0.502 x 0.01 0.02

0.06 0.060.01 0.010.25 0.250.01 0.010.25 0.250.01 0.010.06 0.061.00 1.000.25 0.250.25 0.25

3.47

x 18 in. a 12 i . high

ASSET REREMOVED

BASKET

TO DGRESER OODWITH CLEAN(PARTS

CONVEYOR

VAPOR LEVEL SENSOR

. -. DDRYERSECTION

~ (ABOVE)

*TANK

- -- - LIOUr o

NEATER COIL

CONTROL

Fig. 8. Detraser

]

25

Avg number of parts carried in an 18-in.-long basket"18 "*90.193

Major parts to be cleaned " 90,000/day (2 shifts).

Allowing 1.8 ft as the basket spacing, center to center, with the

baskets moving in a single line, length x12 - 2100 ft. With two-shift operation, this distance must be travelled in 14 hr.

Speed "Sed 14 x 60

" 2.5 ft/min

For a 5-min residence time, trough length " 5 x 2.5 " 12.5 ft.

Assuming effective operation for a 14-hr day, a basket of parts would exit every52 sec.

Cost of Equient

Originally, it had been thought necessary to have two degreasingunits, operating side by side. The cost of each of the units had beenestimated to be $25,000, including trough, conveyor, heat supply (electric)and control equipment, and drying oven. On this basis, $50,000 was specifiedfor this operation in preliminary calculations. By rearrangement of thematerials flow pattern, it now appears feasible to consolidate the operationinto a single unit as described above. No change in the total labor require-ment is contemplated.

Degreasing unit $25,000

Labor Requirement

The degreaser is fed by the takeoff men at the parts fabricationarea. Its action in cleaning the parts is essentially automatic. Oneattendant at the takeoff end of the degreaser should suffice.

1 takeofi man (2 shifts) * 2 man-days/day.

5.0 Electrode Assembly

Choice of Method. The various parts and products required for theelectrode assemblies are loaded manually into feed maigasines on the assemblymachines. These machines are conceived of as being automatically operatedwith a minimum of operator assistance.

Prior to electrode assembly, the frames, current collectors, plaques,insulators, etc. are all prefabricated and ready. The Parts Fabrication sectionof this report (Section 2.0 above) describes assembly of the screens with theframes in a special machine, using staples (the frame material is 0.005 in.thick, making stapling to the screens feasible). Other parts and materialseither are purchased ready for use or have been prepared for this step. (See

26

flowsheets and pertinent sections of this report.)

Each machine line consists of a conveyor and a number of work stations.Each station is assigned one or more assembly steps, depending on the complexityand the time required for the steps. The time allotted at each station is30 sec. Automatically controlled mechanisms feed the various parts and productsfrom the magazines to the stations in the proper sequence. Other automatedequipment performs spot welding, seal welding, addition and distribution ofactive material powders, vibration to distribute the powder in the plaques,and other operations as required.

The active material powder-Al for negative electrodes and Fe endFeS2 (and CuS2 if its use is found desirable) for positive electrodes--is fedto appropriate feed hoppers on Lhe machines. From there, they are metered inthe appropriate quantities. To minimize the danger of segregation orstratification of the cathode materials, it is deemed preferable to blendthese as they are fed to the electrode plaques. This will require that adevice be developed for this purpose.

When an electrode has been assembled, it is pushed onto a platformor an interim storage rack which has space for a number of electrodes; fromthere, it is loaded manually on one of the pallets used for general transportaround the plant.

Assembly of Negative Electrode (Anode) (5.1)

The negative electrode (anode) consists of a frame, a plaque,aluminum powder, and a preassembled screen with frame to cover and containthe plaque and the powder (see Fig. 9). Since there are twice as many anodes

Top Fu,-- --- - -- ANOScNIS

Lia Notion Few

Fig. 9. Anode Assembly

S STaTION (Schematic)

Fu S Outu1", SAIONm2

Siaiim S

as cathodes, if the machines are to operate at the standard rate of one unitevery 30 see, six machines are required. By designing three machines induplex construction, certain economies can be effected. For example, asingle feed hopper for frames, plaques, or aluminum powder can feed alternately

27

to the two sides of the station. The timing of the operations on the two videcan be staggered. The operator's work is also more efficiently organized. Forthis operation, therefore, there will be three duplex assembly machines, eachproducing two anodes every 30 sec.

The operations are as follows:

Station 1

A frame is placed horizontally on the conveyor and a plaque is

deposited in the frame.

Station 2

An automatic distributor device spreads aluminum powder evenly andin measured quantity over the plaque. Simultaneously, the frame and plaqueare vibrated to uaaorb the powder and distribute it throughout the plaque.

Station 3

A preassembled screen with frame is placed over the bottom frame,plaque and powder. The top frame is spot-welded to the bottom frame, forminga completed, discharged anode.

Assembly of Positive Electrode (Cathode) (5.2)

Three assembly machines are required, each with six stations handlingone electrode in various stages of assembly. A positive electrode consists ofcoven parts plus FeS2 + Fe powders. The parts are 2 screens with frames(preassembled), 2 BN paper separator baskets, 2 plaques, and a current collector(see Fig. 10).

The operations are as follows:

Station 1

1. A screen with frame is placed on the conveyor.2. A BN separator basket is deposited in the frame.3. A plaque is placed in the basket.

Station 2

FeS2 + Fe powder are spread automatically (as described for addingaluminum powder to the anode assembly). The frame is vibrated to distributethe powder.

Station 3

1. A current collector is placed on the powder-filled bottom plaque.2. A plaque is placed on top of the current collector.

Station 4

FeB2 + Fe powder is spread (as at station 2) and vibrated.

28

-F- - - - - - - -.

CUT-OUTFOR LEAD

U1 m mi m m

FRAME + SCREEN

BN SEPARATOR

PLAQUE

COLLECTOR + LEAD

PLAQUE

BN SEPARATOR

FRAME + SCREEN

STATION 1

4 AGu.

mob= mm

7wi

I

STATION 2

STATION 3

STATION 4

STATION 5

STATION 6

Fig. 10. Cathode Asembly(Schmt Ic)

POwDERFILL SPOUT

I

now(i L lr 7

L

29

Station 5

2.2.

A BN separator basket is placed over the powder.A screen with frame is placed over the basket.

Station 6

The top frame is spot-welded to the bottom frame.

Note: The BN baskets must overlap to form a complete enclosureof the FeS 2 + Fe powders.


To conform with the other operations in the plant, the operationsin this section will be timed to produce one cell every 30 sec. There aretwo anodes and one cathode per cell. Hence, the selection of three lines,each producing two anodes every 30 sec, and three lines, each producing onecathode every 30 sec.

Cost of Equipment

Station 1Station 2Station 3Drive, Controls

3 lines

$30,00030,00050,00010,000

$120,000 (each line)

$360,000

Electrode Assbly, Positive (5.2)

Station 1Station 2Station 3Station 4Station 5Station 6Drive, Controls

3 lines

$20,00015,00015,00015,00015,00020,00010,000

$110,000 (each line)

$330,000

Labor Reguirments

man-days/day

Electrode Assmbly. Nesative (5.1)

1 operator per machine (3 machines, 2 shifts)Take-off men: 1 per shift (2 shifts)

6

2

30

man-day/days

Electrode Assembly, Positive (5.2)

1 operator per machine (3 machines, 2 shifts) 6

Take-off men: 1 per shift (2 shifts) 2

Identifiable Problems to be Solved

1. Obtaining adequate current conduction might require thatadditional means be provided for fastening the plaques tothe collectors or frames, or that special conductors beadded.

2. In order to achieve satisfactorily low internal cell resis-tance, it may be necessary to provide heavier tab material(i.e., from the current collector to the lead).

3. No BN separator basket has yet been produced.

6.0 Electrochemical Charging, Positive Electrodes

Choice of Method. Several different ways of making cathodes wereconsidered. One of these consists of first fabricating the cathodes usingFeS2 and Fe, and then electrochemically charging lithium so that the FeS2is converted to Fe + Li2S. Thereby, a discharged cathode would be produced.On recharging, FeS would be formed.

The advantage of this method is that lithium can be introduced intothe system in a manner requiring a minimum use of inert atmosphere. If thetype of shipping containers that we suggest is used, we believe the lithiummetal can be transported and charged to the system without a need for glove-boxes. The resulting electrode, containing Li2S and eutectic salt, can thenbe handled in dry air, and outside gloveboxes. Thus, the necessity forworking in gloveboxes is completely eliminated.

The first approach examined for the electrolysis step was batchoperation, but it soon became apparent that this is very cumbersome. Con-tinuous processing appeared to be feasible, and a continuous process wasselected in which the cathodes pass along a trough between two walls offeltmetal saturated with lithium metal (see Fig. 11 and 12).

Fifteen heat-insulated troughs are required, each 10 in. wide by2 ft high by 110 ft long. The troughs, which are enclosed, form long tunnelsthrough which the cathodes are transported, hanging from conveyor chains.The troughs each contain molten salt (LiC1-KC1). A conveyor carries cathodesdown into the salt, through the salt for the length of the trough, and outagain at the end of the trough. During travel through the molten salt, eachcathode current collector (or cathode lead) is connected to the feltmetalpads permeated with lithium by means of sliding contacts. This creates ashort circuit between the cathode and the feltmetal pad and drives the lithiuminto the cathode forming Li2S. This process involves large currents (of theorder of 200 amp/cell) and consequently heat is generated. Some of this heatis lost through the insulation, and the rest is removed by circulating thesalt through a cooling system. Note that the current collectors must be

100, EXIT

Fig. 11. Longitudinal 'ectIon of L.ithium Charger

LOpp,

lo

.t.

"

INSULATION

i "

.':

04

r i

SALT BATH

32

INSULATION 'CONVEYORCHAIN

CLAMP -CURRENT LEAD

SALT

LEVEL-CURRENT

- COLLECTORS

LITHIUM

- -FEED LINES

Fel tuetal -!- -

// - -RESTRAINER

(PERFORATED)

-/ ~)V ELECTRIC /.

HEATER COIL/

Fig. 12. Cross Section of Lithium Charger

33

immersed in the salt so that the resistive heat may be picked up by the saltand not be dissipated into the air above the molten salt. (The air spaces ofthe troughs contain dry air.) Special charge magazines permit the cathodesto be loaded with a minimum interchange of moist air (in which the electrodesare fabricated) with dry air in the troughs (see Fig. 13).

To prevent bulging or warping of cathodes, each cathode is restrainedby two steel plates, one on each side and clamped together. These restrainerplates (perforated to allow current flow) are applied before the electrodesare placed in the charge magazines.

The troughs are sloped so that they each drain to a low spot at oneend. Fill lines and drain lines are provided. A storage tank above thetroughs ke ps the salt at the desired level by means of level controllers.In normal operation, the bottom drain lines are closed and the salt spillsover a weir (exponential, vertical slot) into a drain line leading to a sumptank below. A circulating pump returns the salt to the overhead storage tank.

The molten salt flows at a rate of about 3.2 gpm in each trough. Thisrate is set by the requirement for heat removal. The heated salt overflowingfrom all troughs is collected in a sump tank. From there, it is pumped througha heat exchanger to the head tank from which the troughs are fed.

The heat exchanger is cooled with a refluxing liquid such as Dowthermor PCB, whose boiling point can easily be regulated by pressure. The stabilityof Dowtherm may be borderline for this application. The desired effluent tem-perature of the salt during operation is between 400 and 425C. The refluxingcoolant is condensed in a ai-- or water-cooled condenser.

An electric heating coil under the bottom of each trough providesheat during startup or during idling (e.g., over weekends). All storage tanks,coolers, and pipes are traced with electric heaters and insulated.

Lithium will be bought in 50-gal drums, each with a valve and acover plate to prevent in-leakage of air. A cap may be used to protect thisclosure during shipment and handling. The cap is removed, the drum is placedupside down in a heating coil, and connection is made to the reservoir ofmolten lithium adjacent to the trough, as shown in Fig. 14. Two slidingplates covering both the valve on the drum and the lithium reservoir areremoved. After purging the space between the two valves with argon, bothvalves are opened to permit lithium flow from the supply drum to the reservoir.As the lithium melts, it is free to flow down into the reservoir. However,gas can enter the drum and displace the lithium only through the lower end ofthe discharge tube in the lithium reservoir and gas can enter the drum onlywhen metal is consumed and its level drops in the reservoir. This providessimple, automatic feed control. The inert gas pressure over the liquid lithiumwill be regulated to balance the hydrostatic pressure of molten salt in whichthe feltmetal pads are immersed. The lithium will be fed into a plenum chamberbehind the pads to allow uniform distribution of the liquid metal. In viewof Phe large difference in the densities of the metal and the salt, it maybe necessary to arrange two or three tiers of these feltmetal pads along thesides of the troughs. In this manner, the difference between the pressuresat the top and the bottom of the pads in any one tier will be reduced, avoiding

INSULATION -f

/

,----

CHARGE MAGAZINEAND AIRLOCK

7e

FEED MECHANISM

NOT SHOWN DOOR IS CLOSED DURINGLOADING OF CATHODESINTO THE MAGAZINE

-K-'-V . * * V

-<i-K

+ - -N

N

LITHIUM

CHARGER

Fig. 13. Loading of Cathode to Lithium Charger

INSULATED

DOOR

1

- 1CATHODES WITH

RESTRAINERS

JIll !Jj

RANSPORT

RACK

400 C

-- I

i

- --bm-_d__.

Z

s Ap,

F--.0-7'

.:'

I r//

3 e.-ftl

35

SUPPLY CONTAINER

Al\, OF LITHIUM

REMOVABLE

PANEL

COVER PLATESREMOVEDBEFOREFLANGES ARE VALVECONNECTED ACTUATORS

i~fINERT GAS SUPPLYCONSTANT PRESSURE(DETERMINED BYDIFFERENCE INHYDROSTATIC PRESSUREBETWEEN MOLTEN Li ANDSALT IN THE LITHIUMCHARGER)

/

/

LITHIUM RESERVOIR

MOLTEN LI

230 C

J4

A-

~~-

Vr~

3-WAY VALVES

FOR PURGING

AND LITHIUM

FLOW

'- -

LITHIUMCHARGER

400C

IN

Fig. 14. Typical Lithium Feed System

,

\

36

the danger of displacement of the lithium through the pores of a pad. Whenthe drum of lithium is empty, the two cover plates are replaced between thedrum and purge chamber and the empty drum is removed and replaced with afull one.


Summary

Basis: Continuous, 24-hr operation of electrolysis lines; 6-hrresidence time of individual cathodes in salt. Fifteen lines are required,each 110 ft long.

Weight of salt to submerge the cathode in each trough:

Lithium required: 2860 lb/day, or 43 gal/day per line

Heat loss from each trough: 21,500 Btu/hr

Heat release in charging the lithium: 55,000 Btu/hr pi

Heat to be removed: 33,500 Btu/hr per trough.

Power required to heat an empty trough to 400C in 6 h

Time required to heat a trough full of frozen salt tofrom room temperature and a power of 27 kit: 38 hr.

Salt flowrate (for cooling): 3.2 gpm per trough

Heat-exchanger surface required to cool salt: 140 ft2

Molten salt temperature required when filling cold trot478 C (892*F)

10,500 lb

er trough

r: 27 kW

400*C

ugh:

Detailed Calculations

Basis: 5000 cathodes charged per day

Operating temperature: 400 C (750*F)

Operating period: 24 hr per day

Physical Characteristics

Electrolyte (salt) LiCl-KC1:

Sp. Gr.: 2.02 at room temp, 1.68 at 400 C

Melting point: 356 C (674 F)

Specific heat, CP: 0.219 (solid); 0.278 (molten)

Electric resistance: 0.5 to 1 0 cm

Lithium:

Sp. Gr.: 0.534

Melting point: 186 C (366 F)

37

Estimated charge time:

6 hr per cathode at 150 to 200 amp

Note: The charge time depends on the current path between thelithium and the cathode. This path sould be as short as practicable.

Calculation of Number of Charge Lines Required

H - Number of lines

N * Number of cathodes being processed per line

T - Turnover per line per day - residenc24tIe, hr

6

H x N x T - 5000Hx~x5000

H x N"5

- 1250

assume H - 15 lines

1250N 15

" 84 cathodes/line

length of one line: 84 x (12 + 2) - 98 ft

add for feed end and exit end: 12 ft: 98 + 12 - 110 ft

cross section of trough: 10 in. wide by 24 in. high

depth of salt - 14 in.; length of salt bath in trough " 100 ft

Weight of salt to submerge cathodes:

14 4x10 x 100 x 62.5 x 1.68 " 10,500 lb salt per trough

Lithium required

259 g per cell

Total: 5000 x 259 4 2860 lb/day

Each line: 28 191 lb/line per day191

Volume: 0.53419162.5 .7 ft3/day per line

This corresponds to: 5.7 x 7.5 " 43 gal/day

Provide approximately one 50-gal drum/day per line

38

Heat losses from troughs

SteelWall

Insulation

Salt

Ambient Air

Nonclature

hi " Film coefficient, salt to steel wall

K " Conductivity through insulation

h2 - Film coefficient, insulation to air

U - Overall heat transfer coefficient: 1 + + 1U hl K h2

assure h * 10 and h2 " 2 Btu/hr *F ft2

K * 0.2b btu/ft2 'F/in. hr

i1 Lf U5 f 1

Ulio 026I

" 0.1 + 19.2 + 0.5

" 19.8

U - 0.05

Heat loss, Q "

A "

Tl*

T2.

Q Q.-

U A (Ti - T2)

660 ft2 (Surface area of each trough)

750*F (400'C)

10001 (38'C) (ambient)

0.05 x 660 x (750 - 100)

21,500 Btu/hr from each trough

Heat release in charaina the lithium

5000 cells per day at 920 V-hr each, with an average voltage of 1.15 V.

5000 x 920 " 4600 kU-hr/day1000

Adjust for the voltage of lithium (instead of the voltage of Li-Al)

4600 x 15 5600 kU-hr/day

L 5 in.

Tl

39

Heat release per trough 5800 x 3413 - 55,000 Btu/hr15 x1

Net heat load per line

55,000 - 21,500 " 33,500 Btu/hr

to be removed by molten salt.

Sensible heat content of trough

specific heat of insulation: assume 0.2 Btu/lb x *F

specific heat of steel: 0.15 at 400C (750F)

density of insulation: 6 lb/ft3

Trough: 16 in. deep x 10 in. wide x in. wall

Trough cover: 12 in. high x 10 in. wide x in. wall

Total weight of trough structure: 3,300 lb

Outside liner for insulation: 2 in. sheet, 800 lb

Total: 4,000 lb

Insulation: 5 in. thick, 6 lb/ft3

circumference: %5 ft "

length: 110 ft

volume: 5 x 1 x 110 " 230/ft3

weight: 230 x 6 " 1,380 lb

Heat content: (above 70F, 21C)

Trough: 4,000 x (750 - 70) x 0.15 " 407,000 Btu

Insulation: 1,380 x 0.2 x1 70 102,000 Dtu

Total heat content of trough with insulation: 509,000 Btu

or: =550 149 kW-hr

Power required to heat an mety trough in 6 hr

BOat input: q2 * Bu/hr

Beat loss: qt "=0.05 x 660 x (TI - 100)

Assm a linear relationship between time and trough twerature,T1, so that at tim, h, the tmerature is T1

forh* T1 .750

for h " 0 Ti "100

Ti 100 + ( h

" 134 * (54'C) is the calculated outer surface tenerature of the insulation.

40

Inserting this in equation 1:

qin"33 (100 + x h - 100

- 33 x x h

ql - 21,450 x H Btu/hr

(T1 - 100) -

wherc M - heat capacity of trough and insulation

Eq2 - q2 x H

Eq1 mf21,450 Hjdh

H rough*" 4,000 x 0.15

- 600 Btu/ F

"insulation " 1,380 x 0.2

" 276 Btu/ F

Since the temperature of the insulation varies from 750F (400C)inside to 130 F (54 C) outside, it has only about one-half the heat capacitythat it would have at a uniform temperature of 750F (400C).

Hence:

Ti- 100 -

or

(Ti - 100) x 738 " Eq2 - Eq1

"q2 x -j 2 1, 4 5 0 x dh

738(T1 - 100) " q2 x H - 21,450 x xH

" q2 x H - 10,725 x H

For Ti - 7507F (400 C) and a heatup time H " 6 hr

q 480.000 + 64.350q2 6

" 544.3506

q2 * 91,000 Btu/hr or "27 kW

41

Time required to heat a trough full of salt from 100F to 750F

Volume of salt: 100 x 1 " 100 ft3

Specific gravity of salt at 750F (400C): 1.68

Weight of salt: 10,500 lb

Heat must be added to heat the salt to the melting point, to meltthe salt (the heat of fusion), and to heat the salt from the melting pointto 750 F (400'C).

Data: The eutectic consists of 58 mol 2 LiCI and 42 mol %KC1. The atomic weight of LiCi is 42.39 and that ofKC1 is 74.55. Total number of moles:

10,500 188 moles(0.58 x 42.39) + (0.42 x 74.55)

Weight of LiCl: 0.58 x 188 x 42.39 - 4620 lb

Weight of KCl: 0.42 x 188 x 74.55 - 5880 lb

Specific heats and heats of fusion are as follows:3

Solid LiCl: C * 0.282 cal/g x 'C at 55C

Solid KCl: C * 0.168 cal/g x 'C at 100C

Avg C of solid eutectic " 4620 x 0.282 + 5880 x 0.168p 4620 + 5880

" 0.219 cal/g x 'C

Molten LiC: C * 15 cal/mol x 'C * 0.357 cal/g x *C

Molten KCl: C - 16 cal/aol x 'C-" 0.216 cal/g x 'C4

Avg C of Molten Eutectic - 4620 x 0.357 + 5880 x 0.216p 4620 + 5880

" 0.278 cal/g x *C

Heat of fusion of the LiCl-KC1 eutectic:5

3.2 kcal/mol; m.p. " 354.3C (670F)

1 g-mol eutectic contains: (0.58 x 42.39) + (0.42 x 74.55) " 55.9 g

To milt one pound requires: S2x 1 .8Ba 103 Btu/lb

Heating of salt

To the melting point: 10,500 x (0.219 x (670 - 100)) * 1,310,000 Btu

Above the melting point: 10,500 x (0.278 (750 - 670)1 * 234,000 Btu

Heat of fusion: 10,500 x 103 " 1,081,000 Btu

Total 2,625,000 Btu

42

Heating of the trough: C * 0.15p

Heat required: 4,000 x 0.15 x (750 - 100) "

Heating of the insulation: C * 0.2p

temp, inside: 750'F (400'C)

temp, outside: 130'F (54'C)

Heat required: 230 x 6 x 0.2 x (750 - 130) -2

390,000 Btu

85,600 Btu

Total 3,100,600 Btu

Time H to heat trough with salt using heat input of 92,000 Bku/hr(" 27 kW):

Heat requtred " Heat input - Heat lose

3,100,600 " 92,000 x H - 10,725 x H

H " 38 hr

Note: For the purpose of these calculations, C has been assumedto be constant for the temperature ranges involved. If final design is under-taken, a more exact treatment may be justified.

Salt circulation and cooling

Question: How mach salt (W, lb/hr) must be circulated to keep thetemperature from rising more than 25'C (45F) on a single pass through atrough?

W x 45 x 0.378 " 33,500 Btu (net)/trough

W 2700 lb/hr

Sp. gr. of salt at 750F (400C) " 1.68

Salt f low " 27001.68 x 8.33 x 60

" 3.2 pm/trough

This eount of circulating salt is small.

Heat-exchanaer surface required for cooling of the recireadated salt

Tonal amount of salt and heat load: 15 x 3.2 " 48 gp.

15 x 33,500 " 502,501 Vtu/hr

Assume we can use a liquid such as Dowtherm, refluxing to a estercondenser:

Assume U " 50

502,500 " 50 x A x AT

AT " (410 - 370) x 1.8 " 720F (22C)

A * 140 f t2 for heat exchanger surface area between salt as4Dowtherm.

43

Molten salt temperature required when filling cold trough

Heat capacity of molten salt in full trough:

10,500 x 0.278 " 2920 Btu/F

Heat capacity of trough: 4000 x 0.15 - 600 Btu/F

Melting point of salt: 675F (356C)

To " incoming temperature of salt, 'F

To arrive at a temperature of 750F (400C):

(T0 - 750) x 2920 - (750 - 70) x 600

- 408,000

':o- 750 40800" -140

T "140+ +7500

" 890F (477'C)

It is concluded that except for temporary freezing of a skin of saltnext to the cold trough, there will be no freezing. The skin will melt asadditional hot salt enters the trough.

The entrance to the pipes and the pipes themselves mest be preheated.

Cost of Equipment

Sumary

15 troughs at $30,000 each (see next page for cost details) $450,000

17 Magazines for feeding cathodes to trough at $4,000 each 68,000

4 Transport racks for cathodes (pipe racks on casters),4 x $2,0 1,000

15 Heated tanks for lithium inert gas blanket systemincluding gas piping and regulators 30,000Salt-circulation system (see next page for cost details) 21,000

Salt cooling:

Piping, controls and two pumps 9,000

Exchanger, condenser, fan, insulation, and heat tracing 10,000

Total $589,000(Round off the total to $600,000)

44

Cost Details

Trough

Trough and hood, 4000 lb $6,000

Insulation, 200-300 ft2 500

Insulation cover, 1200 ft2 , 1/32 in. galvanized steel 1,000

Heater coil (bottom only, 30 kW) 600

Supports 500

Conveyor, supports, drive 15,000

Feltmetal and lithium-supply system 4,000

Coulometers (not for every cathode) 2,000

Total for one complete trough $30,000

Salt circulation system

One overhead tank, 300 ft3 capacity (5-ft diax 16 ft long) 3,000

One sump tank (5-ft dia x 16 ft long) 3,000(sized to contain salt from three troughs)

Heater coils and tracers 1,000

Insulation 2,000

Two pumps and motors 2,000

Piping, insulation, electric heater coils 10,000

Total $21,000

Labor Requirements

man-days/day

To feed the cathodes to the troughs:1 man (3 shifts) 3

To remove the cathodes: 1 man (3 shifts) 3

One man will apply the restrainers to the cathodes and load them onportable racks (Fig. 13) carrying 50 cathodes each. He will also use theseracks to load the charge magazines which feed the electrolysis troughs. Aboutfour racks will be charged each hour.

The other man will remove the cathodes at they leave the charge lines,separate the restrainers from the cathodes, load the cathodes on pallets, andreturn the restrainers to the charge side. le will remove about four cathodesper minute.

Transport of the pallets to the LelL assembly area is done by theutility men.

45


1. The steel used for the troughs must be resistant to dry air at750*F (400 C), in addition to being weldable and inexpensive.

2. The feasibility of attaching the lithium-containing drums tothe system must be confirmed.

3. Retention of molten lithium in feltmetal must be explored. Is amultitiered arrangement of the feltmetal pads necessary to preventdisplacement of the lithium by the molten salt?

4. The magazine for charging the cathodes must be designed.

5. The method of attaching the cathodes to the conveyor chain and

detaching them must be designed.

6. It has been assumed that the BN paper will be sufficientlypenetrated by the electrolyte to permit migration of lithiumions. If this condition is not met, a pretreatment step will beprovided to impregnate the paper with electrolyte.

7. Materials and designs for the sliding contacts and the connections

to the cathodes must be developed.

8. Instruments (coulometers) are needed to determine whether cathodeshave been charged with lithium.

9. Pumps and valves must be chosen that can handle molten salt at750 F (400*C).

7.0 Cell Assembly

Choice of Method. The general philosophy of operation of the cellassembly lines is the same as that described for the electrode assembly lines.There will be three lines, each with eleven processing stations. A processingrate of two cells per minute is planned for each station. The operations arerepresented in Fig. 15 to 28.

Each line assembles the following parts (Fig. 15) into a completedcell:

1 cathode charged with lithium2 anodes complete with aluminum powder1 container, open-top1 cover, complete with feidthrough, negative terminal,

salt-fill stub and evacuation pipe stubanode and cathode leads.

46

ANODE LEAD LrwlANODE (2) COVER

Fig. 15. Preassembled Parts

CATHODE (1) CONTAINER

In the course of assembly, a special spoolpiece is attached (atstation 5) to the salt fill pipe and another spoolpiece to the evacuationpipe. The spoolpiece for the salt fill line consists of a valve with ashort pipe stub at each side of it, provided with connectors (quick-acting).The other spoolpiece is similar except that it contains also a ball checkvalve at the vacuum end (the end opposite to the container end of the spool-piece). This check valve allows relief of gas pressure during preheating ofthe cell prior to salt fill. At the end of the assembly operation, thespoolpieces are removed and returned to the head of the line for reuse.

The operations at the individual stations are as follows:

Station 1 (Fig. 16)

One cathode is placed between two anodes and made ready for inser-tion into a container (automatic operation).

Fig. 16. Station 1

One Cathode is PlacedBetween Two Anodes

Operation: Automatic

Station_2 (Fig. 17)

1. Anode and cathode leads are placed on the electrodes (autocraticoperation).

2. The anode lead is welded (automatic operation).3. The cathode lead is welded (automatic operation).

47

AT LEAD

-lo JoL !-ODE

Fig. 17. Station 2

1. Position the anode lead on the anode2. Resistance-weld the anode lead cross-

bar to the vertical anode tabs3. Position the cathode lead on the

cathode4. Weld the lead to the current

collector


Station 3 (Fig. 18)

1. An open-top container is brought into position to receive theelectrodes (automatic operation).

2. The electrodes are ii:serted in the container (automatic operation).

_1

Fig. 18. Station 3

Lower the electrodes, complete withleads, into the container


Note: This might require special

guide equipment ("Shoehorns")

Station 4 (Fig. 19)

1. The cover (with attachments) is lowered onto the container(automatic operation).

2. The cover is sealvelded to the container (automatic operation).3. The anode lead is sealwelded (automatic operation).

RESISTANCEWELD

ANODE.ir-LEAD

4-

I I

48

WfLZLf

SEALWELD

COVER

COVER IN PLACE

Fig. 19. Station 4

Lower the cover on the containerSealweld the cover to the containerSealweld the anode lead


Note: This operation might require

considerable fixturing

The welder for this job will be a two-torch unit, similar to the oneused to weld the container bottoms. Similarly to the latter operation, 13 secwill suffice to make the peripheral weld. The torches will then be repositioned(automatically); this will require 3 sec. If 3 sec more is allowed to weld theseal around the anode lead and retract the torches, 11 sec of the 30-sec cycleremains for initial positioning of the workpiece. This should be ample. Threemachines will therefore suffice.

Station 5 (Fig. 20)

1. The upper portion of the positive electrode feedthrough isinstalled (manual operation).

2. The spoolpieces are attached to the cell (manual operation).

l

SEALWELD -

1.2.3.

. .

49

BALL CHECKAJ1 VALVE

SHUJT-OFFVALVES

CONNECTORS --

INSTALLfl fl FEEDTH3UFig. 20. Station 5PARTS

1. Attach the spoolpieces2. Install the upper portion of the

positive electrode feedthrough

Operation: Manual

Station 6 (Fig. 21)

1. The spoolpieces are connected to the lines for vacuum, inertgas purge, and leak testing (manual operation).

2. Both spoolpiece manual valves are opened.3. This station is provided with automatically controlled valves,

timers, etc. for the following operations:

3a. The cell is evacuated in two stages to 1 Torr. (The sameequipment is used for this station and for Station 9. See Electrolyte Fill.)

3b. The cell is filled with helium to about 0.5 psig. (Therelief valve is designed to open at that pressure.)

3c. A helium leak check is performed in which the area aroundthe cell (particularly the sealwelds and the feedthrough) is sniffed. Whena leak is indicated by an alarm sounding, the leaking cell is shunted aside.

4. The spoolpiece valve leading to the helium supply is closedmanually.

5. The spoolpieces from the station lines are manually disconnected.

50

L ,#.

HE

LEAK TEST EQUIPM.

ROE

PROBE

VAC

1

RELIEF

VALVE EXHAUST

ROUGHING

PUMP (28 TORR)

VAC

EXHAUST

HIGH VAC PUMP

(1 TORR)

FIG. 21. STATION 6 - LEAK TEST

OPERATION

MODE~1.

-- N- 2.

3A.

38.AUTOMATIC

3C.

4.MANUAL

5.

CONNECT THE SPOOLPIECES TO THE VACUUM AND HELIUM LINES (AT 1).

OPEN BOTH SPOOLPIECE VALVES.

EVACUATE IN TWO STAGES TO 1 TORR.FILL THE CELL WITH HELIUM TO ABOUT 0.5 PSIG (THIS RElIEF VALVEIS DESIGNED TO VENT AT THAT PRESSURE).

LEAK CHECK (DISCARD CELLS THAT FAIL THIS LEAK TEST).

CLOSE THE LEFT SPOOLPIECE VALVE (HE-FILL) ONLY. LEAVING THEVAC. LINE SPOOLPIECE VALVE OPEN.DISCONhNECT THE CELL WITH THE SPOOLPIECES STILL ATTACHED (AT 1).

51

Station 7 (Fig. 22)

The cell terminals are automatically connected to electrical testingequipment, which checks for shorts, activates an alarm if any shorts areidentified, and shunts any faulty cells aside.

Fig. 22. Station 7Electrical Tests

1. Make electric contact betweentest equipment and cell leads

2. Test for shorts3. Discard cells that fail test


Station 8 (Fig. 23)

This station consists of a long enclosed oven (tunnel), throughwhich the cells pass and where the cells are heated to 750 F (400*C) (Fig. 24)before they arrive at the electrolyte fill station (the next station). Therelief valve permits expanding cell gases to escape. The helium introducedat Station 6 assists in transferring heat to the cell contents. Electricheater coils provide the heat. The cell is now assembled, provided withspoolpieces, filled with inert gas, and heated uniformly to 400 C (750'F).

50 FT. FILLSTATION

'C40(

M6 a,~

Fig. 23. Station 8 - Heat to 400C

The cells, with spoolpieces attached and thefill-line spoolpieces valve closed (left), enterthe heating tunnel at left and arrive at the fillstation (station 9) on the right

Operation: Automatic Heating Time: 25 min

No. of Cells on Rack: 50

_

ELECTRIC

TST

Eau I MNT

h h

52

/ /

SPOOLPIECE

INSULATION -0/

/-CELL

c

a0 - HEATER COIL

ROLLERS

Fig. 24. Cell Heat Rack Detail

Station 9 (Fig. 25)

The cell fill line is connected to the discharge line from an over-head salt feed tank, and the vacuum line is connected to the vacuum system.A clamshell heater permits access to the lines during hookup and swings backaround the lines during the filling operation to keep them hot and preventfreezing of salt.

After it is hooked up to the lines and before it is filled withsalt, the cell muvrt be evacuated. It is necessary to provide a means ofevacuating the cells very quickly. The resulting pressure should be lowenough so that after the addition of salt and restoration to one-atmospherepressure, the residual gas bubbles will not significantly affect internalcell resistance. So that the evacuation may be done quickly, the cells willbe evacuated to an accumulator tank from which gas will be continuously pumped.To reduce the pumping load, there will be two such tanks, one operating at27 Torr* and the other at 1 Torr. The cells will be evacuated successivelyto each of these two tanks.

The salt feed tank is provided with a scoop that dips :.nto a poolof molten salt and transfers a measured amount of salt to the fill line. Thetank is connected to an inert gas supply that provides a slight overpressure.A constant level is maintained in the feed tank by means of a float controller.The molten salt will come from the same overhead storage tank used for theelectrolytic lithium charge system. All tanks and lines carrying molten saltare traced with electric heater coils and insulated.

The cell will have free space above the electrodes since the amountof salt used for the fill will be enough to cover the electrodes but notenough to fill the cell. This will allow the fill line to drain and willavoid any spillage when the cell is disconnected from the filling equipment.

eThe geometric mean between 1 and 760.

To VACUUM(SEE STATION 6)

H

OPERATING

MODE

MANUAL

FIG. 25. STATION 9 - SALT FILL

1)2)

3)

4)5)6)

AUTOMATIC 7)8)

9)

10)11)

MANUAL 12)13)

MOVE EMPTY CELL WITH SPOOLPIECES INTO PLACE.

CONNECT SPOOLPIECES TO VACCUM AND SALT FILL LINES.

OPEN LEFT SPOOLPIECE VALVE (FILL LINE).

CLOSE CLAMSHELL HEATERS AROUND SPOOLPIECES.

EVACUATE IN 2 STAGES TO ONE TORR.CLOSE (AUTOMATIC) VALVE IN VAC. LINE.

OPEN FILL-VALVE (SCOOP IN SALT TANK CHARGES FILL-LINE).

ALLOW A FEW SECONDS FOR SALT FILL AND DRAINAGE OF THE

FILL LINE.

CLOSE FILL-VALVE.

CLOSE THE TWO SPOOLPIECE VALVES.

OPEN THE CLAMSHELL HEATERS.

DISCONNECT CELL WITH SPOOLPIECES.

MOVE CELL TO THE NEXT STATION.

53

SALTFILL

34

The procedure in these salt-fill operations (see Fig. 26) i asfollows:

1. An empty cell provided with spoolpieces is moved into place(manual operation).

2. The fill line and the vacuum line are connected (manual opera-tion).

3. The manual valve in the fill line spoolpiece is opened. Asequence timer is then started manually to initiate the automatic operationsthat follow.

4. The clamshell heater closes (automatic operation).

5. The automatic valve on the vacuum line is opened (for the purposeof evacuating the cell, as described above).

6. The automatic valve on the vacuum line is closed.

7. The automatic valve on the fill line is opened, allowing thesalt to flood the cell.

8. A few seconds are allowed for filling and for draining of thefill line.

9. The automatic valve on the fill line is closed.

The cell is now filled with salt from the fill tank, with aninert-gas blanket above it.

now filled with salt from the fill tank, with an inert-gas blanket above it.

10. The two spoolpiece valves are closed manually.

11. The clamshell heaters are opened (manual operation).

12. The spoolpieces are disconnected (manual operation) from thesalt fill line and the vacuum line, leaving the spoolpieces (with the valvesclosed) attached to the cell.

13. The cell is moved to the next station (No. 10) (manual operation).

Each cell assembly line (three in all) ib timed to produce onebattery every 30 sec. However, the above operations will take approximatelytwice this long. Two salt-fill stations per line will therefore be needed.There will be a fork in the conveyor line, permitting the cells to be fedalternately to the two stations. The operator will stand between the two,giving his attention to each in turn. The manual operations at one stationwill coincide with the automatic operations at the other. The time cyclesare estimated to be as follows:

Operation 1 2 sec (manual operation)Operation 2 13 sec (manual operation)Operation 3 2 sec (manual operation)Operations 4-5-6-7-8-9 31 sec (automatic operation)Operation 10-11 5 sec (manual operation)Operation 12 5 sec (manual operation)Operation 13 2 sec (manual operation)

Total 60 sec

55

INSULATION AND ELECTRIC

HEATER COILS

PIVOT

AutVA

SPOOLPIECE

CLANHEA

INSULATION

AND HEATER

1 .~L

'N\N

)MATIC To VACUUM

/LVEYSTEMS

SPOOLPIECE

MANUAL

VALVE

SHELLSPACE

TERCe or u mr-e

EoLL

400 C

MOLTEN SALT

FROM OVERHEAD

STORAGE TANK

4 I>l

007J. LEVEL

CONTROL

-- hEATER

COIL

OVERFLOW

TOSUMP TANK

IOP OF ELECTRODES

NEXT STATION -_ I___

'\

Fi8 . 26. Station 9 - Salt Fill, Detail

CHECK

VALVE

- OLTEN SALT-

4000C

-

.\

_

nnrL%

56

Station 10 (Fig. 27)

The pipe stubs are crimpted and resistance-welded to the cell cover.The pipe stubs are cut above the weld, and the spoolpieces, with the remainingstubs attached, are placed in a container for recycling to Station 5 (see Fig.27 for details of the operation).

Note: The operator at Station 5 will later remove the remaining pipe stubsfrom the spoolpieces.

CRIMPER WELDER CUTTER

ft2@ 1zzcj

- DISTANCE OF MOVEMENT EACH TIME

SPOOL-

PIECES

- -- --

2 1

CUT

CRIMP AND WELD

FIG. 27. STATION 10 - FINAL SEAL

J

"

1. CRIMP PIPE NO

2. MOVE CELL

WELD PIPF. NO.

3. CRIMP PIPE NO

4. MVE CELL

1 CUT PIPE NO.W

WELD PIPE MO.

6.7.

A.

MOVE CELLCUT PIPE NO.

SEPARATE THE

I. 1

1

. 2

12

2

SPOOLPIECES WITH ATTACHED PIPE STUSS.

C9. RETURN SPOOLPIECES TO STATION S (OPERATOR AT STATIONL REMOES THE PIPE STUBS BEFORE INSTALLING SPOOLPIECESON A KEU CELL).

OPERATIONS CHECKED OF IN TACH CDL AR DNE -SImJLTANEOUSLY.

AUTOMATIC 4

i

1

57

Station 11 (Fig.28)

1. Final electrical tests are made for shorts and internalresistance.

2. The cut and sealed pipe stubs are leak-tested.

Engineering Calculations (Electrolyte Fill Only - Station 9)

Salt consumed: 2045 g per cell, consisting of 950 g LiCl and1125 g KC1.

Daily Consumption: 5000 x 920 x = 10,150 lb LiCl

5000 x 1125 x5- 12,450 lb KC1

Total 22,600 lb salt

1gM liii ECA1

Lou: mt

Eu 4"i lis"t

Tu1

La/*Ai

Fig. 28. Station 11 - Final Test

1. Hake electrical contacts between testequipment and cell leads, and test for-shorts and internal resistance.

2. Leak-test pipe stubs (fill and vacuumconnections).

Heat losses from lines and feed tanks

Assum a surfacefor piping. If an overallloss is:

area of 40 ft2 for the three tanks and of 40 ft2

coefficient of 0.05 (see section 6) is used, the

Q - 0.05 x 80 x (750 - 100) a 2600 Stu/hrSince this is such a small value, it is concludedcoils will offset the loss adequately.

Cost of _Buipmnt

Cost Details - Station 9 only

that tracing with electric

Each line has

Fill tankCLershell beaterAutrnation

Each line

$250015005000

Coon Equipment

Salt supply tank (250-gal, withinsulation and tracing)

3 lin

$7,5004,50015,000

3.000

58

Vacuum equipment

2 pumps and motors 2,0002 tanks (18 in. dia x 6 f t tall) 1,000Piping, auto. valves, etc. 1,000

Total cost, 3 lines $34,000

C mt of E a.uimnt

StationStationStationStationStationStationStationStationStationStationStationDrive &

1234567891011Control

- Call Assembly (3 lines)

Each Line

$15,00025,00010,00035,0005,000

15,0005,0005,000

27,00015,00012,00020,000

In Como

$7,000

Total

Labor Requirement

Stations 1,One man per line willwell as at station 5.

2, 3, and 4 are conceived to be automatically operated.load components in the magazines at these stations, as

Stations 7 and 8 are automatically operated.

Station 9 rcquires one man per line.Stations 10 and 11 are automatic, but require one man for product

takeofff, for all three lines.

Sumary (3 lines)

Stations 1 to 4Stations S 6 6Station 9

Product takeoff man (3 lines)

Manf line Menshift man-days/day

111

333

1

666

2

Identifiable problems to be solved

1. Electrode leads and feedthroughs.the design of these items is beinginfluence the assembly sequence.

At the tie of this vriting,developed. Designs might

2. This part of the asbay line is the only part of the processwhere the cell containers will be exposed to air (dry) at 750*7(400'C). Although exposure is brief, adequate resistance ofthe contained material to oxidation must be ensured.

Total

$45,00075,00030,000

105,00015,00045,00015,00015,00034,00045 ,00036,00060,000

$520,000

oL qua p b yi ~v a '/a""

59

3. The connections between spoolpieces, cells, and fill-stationlines must be capable of being made or broken quickly and mustbe tight at 750 F.

4. Valves must be adequate to withstand molten salt at 750 F.

5. Some work may be necessary to develop a technique for leak-testing the sealed-oft pipe stubs on the cell cover.

8.0 Submodule

Case Fabrication (8.1)

For fabricating submodules (each containing 24 cells), stock willbe purchased in flat sheet, cut to size. On the bottoms and tops, a lip mustbe bent up for welding (see Fig. 29). This will be done on one of the samemachines as are used for stamping and bending cell components. Stock for thecase walls (because of their greater dimensions) will be bent to shape in asheet metal break. Holes for the feedthroughs will be punched in the end wall.The walls and bottoms will be welded to form an open-top box.

COVER ENT-UP FLANGE

SJIL

OF

FO ccutousru mrccose

WELD SEAj~-~--- (2)

Fig. 29. Submodule Case

h" w

"D

Ll , -- mm4

60

Assembly (8.2)

A case is filled with cells, and the internal bus bars are attached(see Fig. 30). Since 24 positive and 24 negative connections will be madeevery 4 min, a machine will be developed which will enable an operator tomake these connections in groups. The bond is visualized as being made (forexample) with a relatively low-melting ("550*C) silver solder. Heat will beapplied using gas torches. The bus bars will be purchased in cast form,shaped to fit the cell connectors. A solder clip will be applied to eachjoint as part of the work setup operation. Torching can then proceedautomatically while the operator works on setup of the next submodule to beassembled.

Next, the feedthroughs are manually attached by welding or brazing.Then the cover is applied and is sealwelded in an automatic welder.

The final operation (day shift only) is a manual check for internalshort circuits.


Case Fabrication (8.1)

Welding speed - 40 in./min per torch. Since the work is symmetrical,it is feasible to use two torches and obtain twice the welding speed. If thecan is welded in an upside-down position, one fixture will suffice for both thecase wall welds and the bottom-to-wall weld.

It may be assumed that initial fixturing time can be held to 2 min/caseplus 30 sec to reposition the torches from the side to the bottom weld. Thewelding time per case

" (2 x 16) + (2 x 24) + (2 x 12)2 x 40

" 1.3 min

Number of cans to weld/day " 208

Total time required - 208 (2.5+ 1.3)60

- 13.2 hr

Available time in two shifts - 14 hr. One welding unit will suffice.

61

13 1/2" HEIGHT * 1 1/2" SPACE

OF CELLS

12" HEIGHT

CELLS OF ELECTRODES

FEEDTHROUGIINSULATOR

oMENNEN.BUS BAR

p9-- -. - # - O. - -0-#**o 0o

0 00' ___

H

2---

Fig. 30. 24-Cell Battery

007. mommommal

T

62

Assembly (8.2)

Welding speed - 40 in./min per torch

Assume there is one torch

Assume a fixturing time of 2 min

Welding time - (2 x 24) + (2 x 12)40

- 1.8 min

Total time required " 208 (26+ 1.8)60

- 13.2 hr

Therefore, one unit, operated 2 shifts, will suffice.

Cost of Equipment

Bending equipment (case walls) $ 5,000Hole puncher (tops) 5,000Welder (walls, bottoms) 25,000Welder (feedthroughs) 3,500Connecting bus bars 15,000Welder (tops) 20,000Tester 1,500

Total $75,000

Labor Requirement

man-days/day

Bending, hole punching - 1 man/shift 2Welding, case walls and bottoms - 1 man/shift 2Connecting bas bars - 1 man/shift 2Welding or bracing feedthroughs - 1 man/shift 2Welding, Tops - 1 man/shift 2Testing - 1 man, days only 1

Total 13


It is evident that a great deal of development work is necessaryin this area in order to achieve the desired speed and economy in theseoperations. For automatic welding, rapid fixturing is essential. Forconnection of the bus bars, the assumption that suitable dimensional toler-ance can be maintained in a cast part will have to be checked. Carefuldevelopment work will be needed on the method of heating the parts to bracingtemperature.

The prospect of heating and cooling a sealed box of this size raisesthe problems due to the variations in internal pressures that will result.

63

Furthermore, mild steel will corrode (at least slowly) in air at the operatingtemperatures. This suggests that the submodule cans should be connected to asupply of nonreactive gas (e.g., nitrogen) when they are installed. The costof such an installation is not included here.

9.0 Materials Handling and Storage

Materials handling and storage are handled primarily by the utilitymen. Their responsibilities include receiving incoming raw materials, move-ment and storage of work in progress, and shipping. They may also be assignedcertain operating duties. A statement of their functions follows.

Duties of Utility Men man-days/day

3 men (day shift)Incoming materials, handling, and shipping 3

1 man/shift (2 shifts)General handling of materials and shippingHaul finLed cathodes from electrolysis

(6.0) :- .ell assembly (7.0) on firstand second shifts 2

1 man/shift (2 shifts)Haul supplies and parts to stamp and bendmachine (2.1) 2

1 man/shift (2 shifts)Haul supplies and parts to stapling machine(2.2)

Haul cut container tubing from cutter (2.3.1)to degreaser (4.0) and back to welder (2.3.2) 2

1 man/shift (2 shifts)Haul supplies and parts to electrodeassembly machines (5.0). (This man probablywill need help from one of the other utilitymen assigned to general duty.) 2

1 man/shift (3 shifts)Make rounds of operating equipment(electrolysis units, pumps, dry roomequipment, etc.) to record the conditionsand make necessary adjustments. Haul finishedcathodes from electrolysis (6.0) to cellassembly (7.0) on the third shift. Help otherutility men as appropriate. 3

Total 14

10.0 Shipping

Shipping is handled by the utility men. See Section 9.0, MaterialsHandling and Storage, which summarises the assignments of the utility men.

64

11.0 Buildings and Services

Since the provision of a dry room is an essential feature of theplant, it deserves specific discussion. In this case, the area to be protectedagainst atmospheric moisture is estimated to total 7400 ft.2

We have been told by personnel from Eagle-Picher that they have adry room of 3000 ft2 which cost $150,000 or $50/ft. 2

Applying the 0.6 rule gives

7400 - 2.47; (2.47)0.6 - 1.723000

1.72 x $150,000 - $258,000

$258,000 - $35/ft27400

We have also been informed that Sandia has a 15,000 ft2 room whichcost $195,000 or $13/f t.2 If the Eagle-Picher cost of $50/ft2 is used asa base, a room of 15,000 ft2 would cost $26/ft2 by the 0.6 rule. Thus theabove estimate of $35/ft2 appears to be conservative.

Equipment Cost

Dry room: $258,000

65

APPENDIX A - DETAILED FLOWSHEET FOR PROCESS

BI.Separators

LiCI-KCI Saltsalt Purifier

FeS2 FeS2Granules Drying

Fe FeO

Powder Reduction

Powder

Electrode DereasePlaques

AlPowder

ScreensStampForm

SPunchStee u nFrae

ForCelsAoe rame

Steep For Container Join Container

Battery Case Bottoms and otn

L Steel Container - - - - erae

Coytaner _Assemble

Fill- & Evac.- x r iFittingsLe oubes DegreaseI--

Cell To Sta. 2leadsMain

Assembly

Battery To Sta. 2Bus Bars BatteryAssembly

CseTo Sta. 35 %Fdthrougs h Battery

Note: Where decreasing Is indicatedIt Is done in a common degreaser.

(,rmndm9 Blend F 2S Screen -- At Std Plaque BN Fe + FeS2 " Cu25 Piaq,,e Cu2S B

Tabrrng 2 a,4 , ,

PcSta. 1Sr Sta. 2 Sta. 3 Sta. 4 Sta. 5Padd FrN&Sp -- Add FeS - Add Collector r Add FeS -- Add BN Sep.

Add Plaque' irpck AdPaue Vibrnpack Add Screer

Screen CouectorScreen

Cathoder

F C Screen & Frame Sta bframes Cathode Bottom/ Spot*erdAnodes 3

Cathodes Stapler Screen & Frameoins Screens Cathode Top Cathode

Screens and Frares

Cathods Screen & Frame) AnodeAnodes / Plaque Ar Screen

Sta. I Sta. 2 Sta. 3Place Frame Add Al Ponder Add ScreenAdd Plaque Vibropack Spotweld

Ce I leads

Degrease

Main Cell Assembly

Salt Li

Electrochen. ICathode Sta. I Sta. 2 rSEa. c-3 StaLithium Assemble Attach Leads -- e trdes into CoverCharge Electrodes k eld Co er Sealeld

Cathode Anode

ContainerCover

)

Container iOpen top j

Cover ,sithe

1Braze

Battery Case

Battery CaseBettor

Jon Sall %ater

and Bottoi asterSealiweldCse

BittervBcase

Sta. 5 Sta. 6 Sta. 7 Sta. 8

Attach E vacuate Electrical Heat Rack

.Spool Pieces Purge Tests iShortsi ITo 400 Ci

leak Test

Sta. 10

Fil ih WedteakTestElectrolyte Removetspool Elect. Test

PieeCompleted Feedthroughs

Ste. I Sta. 2 Sta. 3

Batter 0 Install Add Feed- BatteryAeby Bus Bars through Assembly

AsebySolder Sealweld

"Bus Bars

Battery Case Se Sta. 5InstallLeak Tests

CoverEec.TssSealweld lcrTet

Battery Case Cover ShipCompleted

Batte: y

----

J

/ battery Ca::S Cover

66

APPENDIX h - CHANGES FROM PREVIOUS PLAN

The material contained in this report was used as the basis for the costprojections in a paper presented at the IEEE Southeastcon 75.6 Since thatpaper was written, we have made a few changes in the details of the manufac-turing procedures: If the reader should wish to compare the documents, thechanges are as follows:

Equipment Changes

Orig. Cost, Revised Cost,Area Change Made thousands of dollars thousands of dollars

2.3.1 Eliminate 2 container cuttersthat each cost $25,000 75 25

2.3 Eliminate conveyor, 2.3.1 to2.3.2 15

2.3.2 Add $10,000 per welder 60 90

2.1 Add die for submodule covers andbottoms - 5

4.0 Eliminate one degreaser costing

$25,000 50 25

7.0 Add $10,000 per welder atStation 4 75 105

8.0 Modify equipment for submoduleassembly 50 75

Total 325 325

Labor Changes

The labor-total shown in the earlier paper was 88 man-days/day. Thisfigure was rounded off to 90. Since then, two man-days/day have been addedto area 1.0, Raw Materials Pretreatment. This brought the actual total to90, where it was allowed to stand.

Materials Cost Changes

For the price of lithium metal purchased in large volume, the priceused in the paper was based on a phone conversation with Dr. H. R. Gradyof Foote Mineral. The following month, a letter was received from himstating that on further consideration the price should be increased (from$6.50-7.00 per lb to $7.50-8.00/lb). This added $0.62/kW-hr to the materialscost, which showed up as an increase of $0.82 in the wholesale selling priceof the battery.

Finally, no allowance was made in the earlier paper either for plantlosses due to nonconforming product or for reclaim credits based on salvageof lithium values from over-age units which failed in the field. Althoughit is virtually impossible to predict plant losses at this time, a figureof 5% of basic materials cost has been added to represent the net cost ofsuch losses (less their salvage value). Recycle credits were taken to be 25%of the basic materials cost of lithium and lithium chloride.

67

REFERENCES

1. P. A. Nelson et at, High-Performance Batteries for Off-Peak Energy Storage,Progress Report for the Period July-December 1974, ANL-75-1 (1975).

2. A. M. Gaudin, Principles of Mineral Dressing, McGraw-Hill, New York,N.Y. (1939).

3. Handbook of Chemistry & Physics, 44th ed., pp. 2365-6.

4. Molten Salts Handbook, G. J. Janz, p. 200.

5. ibid., p. 192.

6. R. 0. Ivins et at., Design of a Lithium/Sulfur Battery for Load-Levelingon Utility Networks, Proc. 1975 Southeastcon, IEEE Region 3 Conf., Vol. ICharlotte, N.C., April 8, 1975.

distribution category: energy storage-electrochemical

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