warehouse protection of cartoned lithium ion batteries - …/media/033af012f21345b7a0bc… · ·...
TRANSCRIPT
Warehouse Protection of Cartoned Lithium Ion Batteries
Presented by:
R. Tom Long, Exponent Inc.
Benjamin Ditch, FM Global
2017 NFPA Conference & Expo
22
Li-Ion Battery Hazards and
Characterization
R.T. Long
3
Project Timeline
• Phase 1, 2010 - Hazard Assessment
• Phase 2, 2013 – Survey & Reduced
Commodity Full Scale Tests
• Phase 3, 2016 – Full Scale Suppression
Tests
• All full scale testing conducted by FM Global
• Funded by PIRG through FPRF
20 Ah
Phase 3, 2016
Polymer
2.6 Ah
Phase 2, 2012
Cylindrical
Polymer
Power tool
packs
Reduced-
commodity
evaluation
Sprinklered
fire test
20 Ah
Phase 3, 2015
Polymer
4
Battery Descriptions
• Battery characterization
– 2.6 Ah cylindrical (18650)
– 2.6 Ah polymer pouch
– 26 Ah power tool packs
– 20 Ah polymer pouch
• Aspects of batteries analyzed
– Battery: Chemistry, electrolyte mass, voltage, SOC, etc.
– Packaging: cartons, dividers, etc.
– Significant effort to understand “what” was being tested
Phase 2
Phase 3
5
What is a Li-ion Cell?
6
What is a Li-ion Battery?
• A Li-ion battery pack contains
– An enclosure
– One or more cells
– Protection electronics
7
Why is Li-Ion different?
• Unique hazards for Li-ion technology
– Fire can initiate within the battery
– Flammable Electrolyte
• Failure mode dependent on battery type
– Venting mechanism
– Chemistry
– State-of-charge
• Packaging or system components
– Other contributions to fire development
8
Cell Thermal Runaway
1. Cell internal temperature increases
2. Cell internal pressure increases
3. Cell undergoes venting
4. Cell vent gases may ignite
5. Cell contents may be ejected
6. Cell thermal runaway may propagate to adjacent cells
Cell
windings
Open center of
cell
Blockage in
center of cell
Pressure
buildup at base
9
Thermal Runaway- How do you get there?
• Thermal Abuse: Exceed the thermal stability limits: external heating
• Mechanical Abuse: Can cause shorting between cell electrodes, leading to localized heating that propagates and initiates thermal runaway;
• Electrical Abuse: Overcharge, External Short Circuit, Over-discharge
• Internal Cell Faults: For commercial Li-ion packs with mature protection electronics packages, the majority of thermal runaway failures are caused by internal cell faults
10
Battery Life Cycle Hazards
• Key Finding: Warehouse setting was frequent throughout lifecycle of batteries
• Warehouse setting
– Failure modes:
• Mechanical abuse – cells being crushed, punctured, dropped
• Electrical abuse – short circuiting improperly packaged cells/ packs
• Thermal abuse – external fire
• Internal fault – unlikely unless cells being charged
– Mitigation:
• Cells/packs usually stored at reduced states of charge (50% SOC or less)
• Cells/packs can be contained in packaging to prevent mechanical and external short circuit damage
• Fire suppression strategies
11
Knowledge Gaps
• Gap 1: Leaked Electrolyte & Vent Gas Composition
• Gap 2: Sprinkler Protection criteria for Li-ion Cells
• Gap 3: Effectiveness of Various Suppressants
• Gap 4: Post – Fire Cleanup Issues
12
Gap 2: Sprinkler Protection
• NFPA 13 - No fire protection suppression strategy for Li-ion cells
• Infrastructure for most occupancies allows for water based protection
• Is water appropriate extinguishing medium for Li-ion batteries?
• NFPA 13 Table A.5.6.3:
– Dry cells (non-Li or similar exotic metals) in cartons: Class I (e.g. alkaline)
– Dry cells (non-Li or similar exotic metals) blister packed in cartons: Class II (e.g. alkaline)
– Automobile batteries – filled: Class I (e.g. lead acid water-based electrolyte);
– Truck or larger batteries, empty or filled Group A Plastics (e.g. lead acid water-based electrolyte);
• Li-ion chemistries are not included
• Full Scale testing appropriate
13
For full scale tests - need to define
• Commodities– Cell chemistry
– Cell size / form factor
– Cell SOC
– Packaging configuration
• Storage geometries and arrangements
• Full scale tests of every cell type / configuration is not practical– Select “most typical types”
• Purchasing commodities for testing is expensive
14
Survey
• 2012
• Responders typically engaged in:
– Manufacturing
– Research
– Recycling
– Almost all responders stored batteries, cells, or devices with batteries/cells.
15
Survey Responses Summary
• Battery Types at the Surveyed Facilities: Cylindrical cells were the most common form factor. Small format was the most common size.
• Tasks Carried Out at Facilities Surveyed: Most of the responding facilities were engaged in the storage of cells, battery packs or devices.
• Packaging of Received Batteries: Cells typically arrive in cardboard boxes. These boxes may be on wooden pallets and/or encapsulated.
• Rack storage type: Movable racks were more common than fixed racks, and shelves were more likely to be perforated than solid.
16
Flammability Characterization
• Full scale tests
• Limited quantities of batteries/cells
• Rack storage arrangement
• Free burn/external ignition source
• Hard and soft case batteries with similar energy densities
• Battery packs with appreciable plastics
• Due to costs, tests required an unique approach to full scale tests: FM Global – reduced commodity testing
17
Battery Acquisition and Characterization:
Phase 2 Reduced Commodity Tests (RCT)
Parameter Power tool packs
18650
18650 cells Li-Polymer cells
Nominal voltage 3.7 V 3.7 V 3.7 V
Nominal capacity 1300 mAh 2600 mAh 2700 mAh
Mass of Cell 42.9 g 47.2 g 50.0 g
Approximate mass of
electrolyte solvent
3.3 g 2.6 g 4.0 g
Cell chemistry Lithium Nickel
Manganese Cobalt
Oxide (NMC)
Lithium Cobalt
Oxide (LCO)
Lithium Cobalt Oxide
(LCO)
Approx. state of charge (SOC)
as received
50% 40% 60%
18
Power Tool Packs – Overview (RCT)
• 18 V, 48 Wh Lithium-Ion power tool packs Ryobi P104
• ~(5 ½” long) x (3 ¼” wide) x (4 ¼” tall)
• Blister packs plus casing presented an appreciable amount of plastics
Onboard “fuel gauge” indicator lights orange, indicating mid state of charge
19
Power Tool Packs – Construction (RCT)Hard injection-molded plastic shell
Rubber feet
Hard plastic frame
Soft foam padding
Protection printed circuit board (PCB) / Battery Management Unit (BMU)
Flexible rubber padding
20
Power Tool Packs (RCT) Characterization
• High-Power Lithium-Ion Cells• Form Factor: 18650 Hard case cylindrical cells x 10, 5 series 2
parallel configuration• Dimensions: 18 mm x 65.0 mm• Cell enclosure: steel can with shrink wrap• Chemistry: NMC (Lithium Nickel Manganese Cobalt Oxide)• Nominal voltage: 3.7 V
• 5 series elements @ 3.7 V nominal = 18.5 V nominal pack voltage
• Nominal capacity: 1300 mAh• 2 parallel elements @ 1300 mAh per cell = 2600 mAh capacity
• 18.5 V x 2.6 Ah = 48.1 Wh nominal pack energy• Approximate assembled weight: 42.9 g• Approximate mass of electrolyte solvent: 3.3 g
(+) side (with vent port) (-) side (no vent port)
Positive terminal and vent port
21
Power Tool Packs – SOC (RCT)
• Two battery packs were measured for voltage and capacity
– Both battery packs were 18.60 V (corresponding to 3.72 V per series element)
– Battery packs are close to the nominal pack voltage of 18.5 V (or nominal cell voltage of 3.7 V)
– A battery pack at the nominal voltage usually indicates it is near the halfway point of charge
– A fully charged pack would be 21 V (4.2 V x 5 series elements)
• State of Charge (SOC) was measured on one cell from each of two battery packs (S/N listed above) using a standard C/5 rate (0.26 A) constant current discharge until 2.5V was reached
– cells were determined to be close to 50% SOC
V of NFPA-sanyo-18650.015
V of NFPA-sanyo-18650.008
Capacity/mAh
6005004003002001000
Vol
tage
/V
4.2
4.1
4
3.9
3.8
3.7
3.6
3.5
3.4
3.3
3.2
3.1
3
2.9
2.8
2.7
2.6
2.5
Discharge CapacityPacksCS12233D430739 – 667 mAh (50% SOC)CS12271N430014 – 652 mAh (49% SOC)Initial voltage 3.72 V
22
Power Tool Packs -Cell Disassembly (RCT)
• Electrodes are in a jelly roll configuration, typical of 18650 cells – Sanyo 18650
• One cell was disassembled and the positive electrode was subjected to energy dispersive X-ray spectroscopy (EDS) for cell chemistry
• Cell chemistry is consistent with NMC (lithium nickel manganese cobalt oxide) chemistry, i.e. Li(NixMnyCoz)O2 where x, y, and z can vary depending on manufacturer’s formula
Negative electrode (on Cu foil)
Positive electrode (on Al foil)
Separator
Separator
Mn
Co
Ni
Positive cell tab
EDS Spectrum
O
Steel can
23
18650 Cells – Characterization (RCT)
• 18650 Lithium-Ion Cells• Form Factor: Hard case cylindrical cell
(18 mm diameter x 65.0 mm)• Cell enclosure: steel can with shrink wrap• Chemistry: LCO (Lithium cobalt oxide)• Nominal voltage: 3.7 V• Nominal capacity: 2600 mAh • Approximate assembled weight: 47.2 g• Approximate mass of electrolyte solvent:
2.6 gJelly roll in cell can
24
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
0 0.2 0.4 0.6 0.8 1 1.2
Volta
ge (V
)
Capacity (Ah)
18650 Channel 8
18650 Channel 15
18650 Cells – SOC (RCT)
• Two cells were measured for voltage and capacity
– Both cells were 3.74 V, close to the nominal cell voltage of 3.7 V
– A battery pack at the nominal voltage usually indicates it is near the halfway point of charge
– A fully charged cell would be 4.2 V
• State of Charge (SOC) was measured on two cells using a standard C/5 rate (0.52 A) constant current discharge until 3.0 V wasreached
Discharge Capacity Cell capacities:1.05 Ah (40% SOC)1.05 Ah (40% SOC)
Initial voltage 3.74 V
25
18650 Cells – Cell Disassembly (RCT)
• Electrodes are in a jelly roll configuration, typical of 18650 cells
• One 18650C was disassembled and the positive electrode was subjected to energy dispersive X-ray spectroscopy (EDS) to assess cell chemistry
• Cell chemistry is consistent with LCO (lithium cobalt oxide) chemistry, i.e. LiCoO2
Steel can
Negative electrode (on Cu foil)
Positive electrode (on Al foil)
Separator
Separator
O
CoEDS Spectrum
26
Li-Polymer Cells – Characterization (RCT)
• Lithium-Polymer Cells• Cell enclosure is aluminum foil coated with polymer, and
is designed to be electrically neutral and insulated• Form Factor: Li-polymer (soft pack) cell • Dimensions: 6 mm thick x 41 mm x 99 mm• Cell enclosure: aluminum foil with polymer coating• Electrode configuration: jelly roll (as opposed to stacked)• Chemistry: LCO (Lithium cobalt oxide)• Nominal voltage: 3.7 V• Nominal capacity: 2700 mAh • Approximate assembled weight: 50.0 g• Approximate mass of electrolyte solvent: 4.0 g
Coated aluminum pouch
Cell windings (“Jelly roll”)
+ tab
– tab
27
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
0 0.5 1 1.5 2
Volta
ge (V
)
Capacity (Ah)
Pouch 9I19
Pouch 9H27_1
Li-Polymer Cells – SOC (RCT)
• Two cells were measured for voltage and capacity
– Both cells were 3.84 V
– Battery packs are close to the nominal cell voltage of 3.7 V
– A battery pack at the nominal voltage usually indicates it is near the halfway point of charge
– A fully charged cell would be 4.2 V
• SOC was measured on two cells using a standard C/5 rate (0.54 A) constant current discharge until 3.0 V was reached
Discharge CapacityCell markings:9H27 – 1.62 Ah (60% SOC)9I19 – 1.66 Ah (61% SOC)
Initial voltage 3.84 V
28
Li-Polymer Cells – Cell Disassembly (RCT)
• Electrodes are in a jelly roll configuration, as opposed to stacked electrode design
• One Li polymer cell was disassembled and the positive electrode was subjected to energy dispersive X-ray spectroscopy (EDS) to assess cell chemistry
• Cell chemistry is consistent with LCO (lithium cobalt oxide) chemistry, i.e. LiCoO2
AlPouch
Negative electrode (on Cu foil)
Positive electrode (on Al foil)
Separator
Separator
O
CoEDS Spectrum
29
Suppression Test: Battery Cell Description
Lithium-Ion Pouch Cell
• Dimension: 9×6×0.3 in.
(230×150×8 mm)
• Weight: 1.1 lb (0.5 kg)
• Capacity: 20 Ah
• Voltage: 3.3 volts
30
Suppression Test: Electrical Characterization
• Stacked Electrode Design
• Cell Chemistry: Lithium Iron
Phosphate (LiFePO4)
• As-Received SOC: 49.4%
• Electrolyte Mass: 0.083 lb
(34 g)
31
Suppression Test: Package Description
17”
6.5”
13.5”
• Cardboard box: 17×13.5 ×6.5 in.
(430×340×170 mm)
• Total weight: 27 lb. [including cells]
(12.2 kg)
• Contents:
• 20 battery cells
• White polystyrene crates
• Polyethylene bubble wraps
32
Suppression Test: Battery Package Mass
SummaryContent per One
Package
Weight
20 Battery (including
Electrolyte)
21.7 lb
(80.5%)
10 White Battery Crates 3.9 lb
(14.3%)
Cardboard 1.4 lb
(5.0%)
Parking Material 0.04 lb
(0.1%)
Electrolyte 1.7 lb
(6.2%)
Total Weight 27.0 lb
Cardboard Box, 5.0%
Packing Material (Bubble Wrap), 0.1%
Ten (10) White Battery Crates,
14.3%
Twenty (20) Battery Cells
including Electrolyte,
80.5%
FM Global
[ Public ]
EXPERIMENTAL EVALUATION
Benjamin Ditch
FM Global
[ Public ]
Scale
FM Global Research Campus
FM Global
[ Public ]
REDUCED-COMMODITY TEST
Task 1
FM Global
[ Public ]
How to Evaluate Li-ion Batteries
Commodity classification not feasible
– Expensive and difficult to acquire
Reduced-commodity approach
– Limit commodity to ≥ one pallet load per test
– Freeburn (no water)
FM Global
[ Public ]
Reduced-Commodity Test: Design
Storage height: 15 ft (4.6 m)
Protection: none
– Freeburn
Commodity:
– 4 full pallet loads
– 4,480 batteries
Ignition
– Propane, 45 kW
5 ft
1.1
ft
Ring burner
Cartoned Li-ion Batteries
Ignition flue
Non-Combustible Non-Combustible
FM Global
[ Public ]
Reduced-Commodity Approach
Characterize fire development up to theoretical
sprinkler operation
– Test conducted under a Fire Products Collector
– Standard commodities and Li-ion batteries
Compare predicted sprinkler operation time versus
time of battery involvement
FM Global
[ Public ]
Fire Hazard Comparison
Time
He
at R
ele
ase
Rate
Class 2
CUP
Sprinkler operation prediction
(Fire size and growth rate)
FM Global
[ Public ]
Reduced-Commodity Test
30 s 60 s 120 s90 s
20 Ah
FM Global
[ Public ]
FM Global
[ Public ]
Hazard Comparison
FM Global
[ Public ]
Hazard Comparison
FM Global
[ Public ]
Hazard Comparison
20 Ah
FM Global
[ Public ]
Hazard Comparison
FM Global
[ Public ]
QR Sprinkler, 10 ft (3 m) Clearance
Sprinkler: RTI = 50 ft1/2s1/2, 165oF
: RTI =(28 m1/2s1/2), (74oC)
CommodityOperation
Time (s)
Qbe
(kW)
Fire Growth
Rate (kW/s)
Li-ion, 20 Ah
Prismatic Pouch 37 335 33
Li-ion,
small-format43 270 20
Standard
Commodities50 220 16
FM Global
[ Public ]
Comparison to Previous Testing
Similar fire development
– Initial growth dominated by cartons
– Fire size and growth rate similar at sprinkler operation
Time of significant battery Involvement
– Small-format: 300 s
– Large-format: 90 - 180 s
Large-format higher hazard than small-format
FM Global
[ Public ]
Potential Application of Results
Sprinkler protection option established
– Applied to all cells with a hazard ≤ cell used in sprinklered test
– Cell hazard evaluated in reduced-commodity test
Reduced-commodity test Large-scale test
Hazard
comparison
Protection
guidance
FM Global
[ Public ]
LARGE-SCALE TEST
Task 2
FM Global
[ Public ]
Large-Scale Test: Design
Storage height: 15 ft (4.6 m)
Ceiling height: 40 ft (12.2 m)
Sprinkler: K22.4 gpm/psi1/2 (320 lpm/bar1/2)
– Response: quick-response, 165oF (74oC)
– Density: 1.3 gpm/ft1/2 (53 mm/min)
– Spacing: 10 × 10 ft (3 x 3 m)
– Ignition: Offset, under-1 sprinkler
Commodity: 24 pallet loads (~27k batteries)
20 Ah
FM Global
[ Public ]
Existing vs. Typical
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
FM Global
[ Public ]
Existing vs. Typical
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
CU
PC
UP
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Cla
ss 2
Smaller main array
– Reduced damage area
– Minimize target jump
CUP target commodity
– No fire within carton
– Requires early
extinguishment
Increased protection
FM Global
[ Public ]
Warehouse Storage – Success!
One sprinkler provided
effective protection
20 Ah
FM Global
[ Public ]
FM Global
[ Public ]
SUPPLEMENTAL EVALUATIONS
Task 3
FM Global
[ Public ]
Battery-to-Battery Spread
How does thermal run away spread from battery to battery?
1) Combustion of chemical energy– Battery rupture releases flammable electrolyte
– Burning electrolyte produces heat
2) Release of electrochemical energy– Electrical energy is converted to heat
– Heat transferred to adjacent batteries
Results in Fire
Results in Heat
FM Global
[ Public ]
Combustion of Chemical Energy
How much air is needed?
Electrolyte
– Air-to-fuel ratio: 7:1
– Mass per battery: 34 g
Not enough air to burn ONE battery
Fire must burn outside carton
Required AirPer Battery
Available AirPer Carton
0.2 m3 0.01 m3
7 ft3 0.35 ft3
20 Ah
FM Global
[ Public ]
Electrochemical Heat
• Film heaters: 650oF
• Battery at middle level
• Battery rupture @ 5 min
• 2 hour test duration
• Three batteries ruptured
Propagation did not occur
FM Global
[ Public ]
0.3 gpm/ft2
(12 mm/min)
What if batteries do become involved?
Pilot flame
Suppression tests
Internal ignition
Pilot flame outside carton
Water Application Apparatus
– Water applied when batteries are
involved in fire
Allows for water application at a
later stage of battery involvement
than large-scale test Front View
FM Global
[ Public ]
Flue Ignition Scenario
Pilot Ignition
Flame spread
Start of water application Suppression
Final
• Required external pilot ignition
• Fire extinguished
– Water application delayed 168 s
• 70% of batteries damaged
• Battery rupture after extinguishment
32:00
38:00
41:10 55:27
20 Ah
FM Global
[ Public ]
SUMMARY AND PROTECTION
RECOMMENDATIONS
FM Global
[ Public ]
Summary of Protection Guidance
Guidance to be included in FM Global Data Sheets
Sprinkler protection applicable to all tested
batteries, e.g.
Overall protection guidance needs to consider
additional hazards, such as battery projectiles
2.6 Ah: 20 Ah:
FM Global
[ Public ]
Application of Warehouse Storage Test
FM Global
[ Public ]
Application of Warehouse Storage Test
• Protection guidance confirmed
with a large-scale fire test
• Adequacy for other batteries
evaluated with small-scale to
intermediate-scale tests
FM Global
[ Public ]
Application of Warehouse Storage Test
• Protection guidance confirmed
with a large-scale fire test
• Adequacy for other batteries
evaluated with small-scale to
intermediate-scale tests
Application
• Warehouse≤ 15 ft storage
≤ 40 ft ceilings
• Sprinkler Protection– K22.4 gpm/psi1/2
– QR, 165oF
– 12 @ 35 psi
FM Global
[ Public ]
In-Process Storage
Storage up to 5 ft high
– Protect as Hazard Category 3 (HC-3) per FM Global Data
Sheet 3-26
– Recommend including 10 ft (3 m) space separation
– Applies to all Li-ion batteries tested
Cartoned power tool packs up to 15 ft (4.6 m)
– For ceilings ≤ 30 ft (9.1 m), protect as cartoned
unexpanded plastic (CUP) per FM Global Data Sheet 8-9
FM Global
[ Public ]
Acknowledgements
Property Insurance Research Group
Fire Protection Research Foundation
R. T. Long Jr., J. A. Sutula, M. J. Kahn, "Lithium Ion Batteries Hazard and Use Assessment Phase IIB - Flammability Characterization of
Li-ion Batteries for Storage Protection,” Fire Protection Research Foundation, 2013
B. Ditch and J. de Vries, “Flammability Characterization of Li-ion Batteries in Bulk Storage,” FM Global Technical Report, 2013
C. Mikolajczak, M. Kahn, K. White, R. T. Long Jr., "Lithium-Ion Batteries Hazard and Use Assessment," Fire Protection Research Foundation, June, 2011
Property Insurance Research Group
B. Ditch, “Development of Protection Recommendations for Li-ion Battery Bulk Storage: Sprinklered Fire Test,” FM Global Technical Report, 2016
FM Global
[ Public ]
More Data at…
www.nfpa.org/foundation
www.youtube.com
www.fmglobal.com/researchreports
Search: lithium ion,
FM Global
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2017 NFPA Conference & Expo