bmw hydrogen. ichs 2011. -...

Validation of Cryo-compressed Hydrogen Storage (CcH2) – a Probabilistic Approach.

Dr. Oliver Kircher.September 14th 2011, San Francisco, CA.

BMW Hydrogen.

ICHS 2011.

BMW EfficientDynamicsLess emissions. More driving pleasure.

BMW HydrogenICHS 2011San Francisco9/14/2011

Cryo-compressed Hydrogen Storage.Outline.

Cryo-compressed hydrogen

vehicle storage

Validation using a probabilistic

approach

Safety aspects

Outlook and conclusion


BMW Hydrogen Technology Strategy. Advancement of Core Components.

Source: BMW

Advanced key components Next vehicle & infrastructureHydrogen 7 small series

LH2 Storage Capacity

Safety

Boil-off loss

Pressure supply

Complexity

Infrastructure

Technology leap of storage & drive train

Efficient long-range mobility:

Zero Emission.

Focus on medium & large

vehicles with high energy

demand.

Range > 500 km (6 – 8 kg H2)

Fast refueling (< 4 min / 6 kg)

Optimized safety oriented

vehicle package & component

integration

Loss-free operation for all

relevant use cases

Compatibility to upcoming

infrastructure standard

V12 PFI engine Power density

Dynamics

Durability & cost

Efficiency

H2 Drive train

H2-Storage

Electrification

today

H2ICEH2HEV EREV FCHV

FC-EREV

AdvancementStorage & Drive train

CGH2

Source: Dynetek

LH2

Source: BMW

CcH2


Hydrogen Vehicle Storage. Storage Technologies – Only Physical Storage Demonstrated & Validated for Use in Passenger Vehicle.

Physical Storage Solid storage

Single or multi-

pressure vessel

700 (350) bar

Liquid Adsorption

„activated

carbon“

Hydrides

„MOFs“„chemical“

„Zeolith“„organic“

„metallic“

Compressed

CGH2* LH2

*

Source: BMW

Super-insulated

low-pressure Cryotank

Research level!Demonstration

levelSmall Series level,

Mainstream

Source: Quantum

*) CGH2 := Compressed Gaseous Hydrogen (700bar)

CcH2 := Cryo-compressed Hydrogen (10bar - 350bar)

LH2 := Liquid/Liquefied Hydrogen (1 bar_a - ca. 10 bar_a)

CcH2*

Source: BMW

Cryo-compressed

Super-insulatedcryogenic pressure

vessel 350 bar

Prototype level

„organic“


Cryo-compressed Hydrogen Storage.CcH2 – Cryogenic Gas Denser than LH2.

0

10

20

30

40

50

60

70

80

90

100

20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Temperatur [K]

Dic

hte

[g

/l]

Temperature [K]

Den

sit

y[g

/L]

CGH2 – 700 bar / 288 K

CcH2 – 300 bar / 38 K

-40°C

LH2 – 1 bara

LH2 – 4 bara

CGH2 – 350 bar / 288 K

LH2

CcH2

CGH2

LH2 Liquid Hydrogen

CcH2 Cryo-compressed Hydrogen

CGH2 Compressed Gaseous Hydrogen

33 K

80 g/L

63 g/L+27%

x2

40g/L


Cryo-compressed Hydrogen Storage. Concept.

„Insulate a pressure vessel with

a simplified superinsulation,

fill with compressed cryogenic

hydrogen and operate in the

cryo-compressed gas region”

CcH2

20-350 bar

LH2

2-10 bar

Reduce pressure

(700 bar 350 bar)

Simplify insulation

(7W 3.5W)

CGH2

700 bar

+

Combining advantages rather than challenges.


Cryo-compressed Hydrogen Storage. Concept.

„Insulate a pressure vessel with

a simplified superinsulation,

fill with compressed cryogenic

hydrogen and operate in the

cryo-compressed gas region”

CcH2

20-350 bar

LH2

2-10 bar

Reduce pressure

(700 bar 350 bar)

Simplify insulation

(7W 3.5W)

CGH2

700 bar

+Loss-free operation in typical usage +

Pressure supply for ICE-ATL / FC+

High storage capacity +

Low adiabatic expansion energy +CcH2 and CGH2, 350bar refueling option +

System volume -

Fiber cost -

System weight -

Boil-off loss-

Dormancy, autonomy-

Insulation complexity-

Warm refueling time-

Two-phase issues-

Combining advantages rather than challenges.


Modular Super-insulated Pressure Vessel (Type III)

Max. usable capacity

CcH2: 7.8 kg (260 kWh)CGH2: 2.5 kg (83 kWh)

Operating pressure

350 bar

Vent pressure

≥ 350 bar

Refueling pressure

CcH2: 300 barCGH2: 320 bar

Refueling time

< 5 min for 7.8kg (according to SAE J2601)

System volume

~ 235 L

System weight (incl. H2)

~ 140 kg

H2-Loss (Leakage| max. loss rate | infr. driver)

<< 3 g/day | 3 – 7 g/h (CcH2) |

no significant losses

Cryo-compressed Hydrogen Storage. System layout – BMW prototype 2011.

+ Active tank pressure control

+ Load carrying vehicle body integration

+ Engine/fuel cell waste heat recovery

Vacuumenclosure

Aux. systems(control valve, regulator,

sensors)

MLI insulation(in vacuum space)

Refuelingline

Shut-off valve

Intank heatexchanger

Suspension

Coolant heatexchanger

COPV(Type III)

Secondary vacuum module

(shut-off / saftey valves)


Cryo-compressed Hydrogen Storage. CcH2 Capacity & Integration Advantage over CGH2.

7.8 kg* CcH2

120 - 140 kg system**

*) maximum usable H2-mass with 10 bar power train supply pressure. **) based on prototype 2011, including BOT & BOP

Cryo-compressed Hydrogen - CcH2

Com

pre

ssed G

aseous H

ydro

gen -

CG

H2

2200 mm

346 mm design space

> 80% higher usable storage

capacity in given design space.

4.3 kg* CGH2

90 kg system


Cryo-compressed Hydrogen Storage. Extended CcH2 operating regime leads to increased pressure vessel requirements.

1 Refueling (300 / 57 K)

2 Highest possible storage pressure at cryogenic conditions (subsequent to refueling)

3 Extraction to lowest pressure (subsequent to refueling)

4 Highest possible storage pressure at warm conditions (in CGH2 mode)

5 Production preparation step: vacuum bake-out and evacuation

pre

ss

ure

[b

ar]

1

2

35

0

200

400

600

800

1000

temperature [K]

0 40 240 280 320 360

4

80 120 160 200

350 bar CGH2

operating regime(extended) CcH2 operating regime

CGH2 350 bar refueling

out-baking and vacuum generation

CcH2 refueling

currently required burst pressure (2.25 x 350 bar)




vehicle storage


approach

Safety aspects



Cryo-compressed Hydrogen Storage. Validation concept.

Requirement: 99.86% of the storages must not show any hydrogen leakage higher

than the allowed level for 99% of the costumers

CcH2 storage “as safe as” conventional components in conventional cars



Detailed analysis of driving behavior of typical BMW

costumers

Representative average costumer drive cycle

Calculation of pressure & temperature course on

CcH2 storage

CcH2 Validation cycle

CcH2 costumer cycle



CcH2 Validation cycle

pressure

Lin

er

str

es

s

Rp, compr.

Damage diagram

tem

pe

ratu

re

Rp, tensile

Liner stiffness, defined through composite design

Validation cycle represents all relevant loads on

liner & composite

Accumulated damage on liner & composite are

calculated using FE-model & “Miner” method

< 10 validation cycles represent same damage on

liner & composite like one year costumer cycle

CcH2 costumer cycle


Safety factor >>

required safety factor

*) leakage at welded joint

Combined pressure and cryogenic temperature cycling does not lead to

significant degradation of vessel burst pressure

Combined pressure and cryogenic temperature cycling does not lead to

degradation in composite material properties

Cryo-compressed Hydrogen Storage. Validation of structural durability.


Cryo-compressed Hydrogen Storage. Validation of structural durability on sub-scaled vessels.

Cryogenic temperature and pressure cycling does not lead to significant degradation.Cryogenic temperature & pressure cycling does not lead to degradation of cycle life

* 720 Temp. cycles with LN2 105–273K @ 4 bar

** 1440 Temp. cycles with LN2 105–273K combined with 2880 refuelings

*** 1000 Temp. cycles with CcH2 45–273K combined with 4000 refuelings

Pre-loading

Hy

dra

ulic

cy

cle

s t

o f

ailu

re

(2 –

43

.8 M

Pa

)




vehicle storage


approach

Safety aspects



CcH2 storage eases vessel monitoring and mitigates failure impact

Vacuum enclosure & safety release control Low adiabatic expansion energy

Vacuum enclosure design lowers risk of pressure vessel damage (mechanical and

chemical intrusion, bonfire damaging and aging) and enables leak monitoring.

Redundant safety devices for controlled hydrogen release in case of damage or vacuum

failure.

Cryogenic hydrogen contains a low adiabatic expansion energy and thus, can mitigate

implications of a sudden pressure vessel failure, in particular during refueling.

Cryo-compressed Hydrogen Storage.Safety Aspects.

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

CcH2

Ad

iab

ati

c e

xp

an

sio

n e

ne

rgy

[k

Wh

/kg

]

Full CcH2 storage

after cold refueling

6 – 15 times

lower expansion

energy

Ambient CGH2 storage

after refuelingVacuum

Enclosure

Redundant Safety Devices

COPV in vacuum environment


Cryo-compressed Hydrogen Storage. Safety – status & scheduled tests.

Topic Explanation Status

Vehicle CrashNo additional implications compared to vehicle crash with CGH2

storage expected.

Tests will be done during vehicle qualification in 2012/2013

Vehicle fireVacuum insulation & multiple safety devices (PRDs & TPRDs) lowerrisk of vessel failure.

Bonfire test will be done in 2011, localized fire test in 2013.

Burst energy

Adiabatic expansion energy in case of sudden vessel failure ismitigated in cryogenic gas storage compared to warm gas storage:

- Simulation: @ T < 100 K liquefaction during expansion supposable

- Validation: burst test under warm & cryogenic conditions showsignificant differences

Sudden vacuum loss

Validation of safe H2-discharge via pressure relief devices (andoptional vacuum-casing burst disc) in case of Air- or H2- sidedvacuum loss.

Implication of air-side vacuum-loss is mitigated compared to LH2.

Impact damage, penetration, chem. exposure

Vacuum enclosure lowers risk of pressure vessel damage throughexternal impacts.

Tests will be done during vehicle qualification in 2012/2013.

Permeation & Leakage

Type III pressure vessel design with welded boss, joints andvacuum casing eliminates issue of permeation and mitigates risk ofleakage compared to CGH2 storage.

Leakage rate << 3g/day.

AirH2

Vacuum-

loss

Crash

Bonfire Local. fire


Cryo-compressed Hydrogen Storage.Safety Aspects – potential burst energy CcH2 vs. CGH2.

Simulation* indicates lower energy shockwave for cryogenic hydrogen

* Simulation performed with self-similar propagation of shock-wave according to Riemann

burst pressure 300 bar


P06

P02/P07

P03/P08

P04/P09

P05/P10

P01

V2-4 av = 401 m/s

v4 = 375 m/s

V2/3 = 428 m/s(Signal of P03 not

considered)

(v1 = 394 m/s)

(v1 = 482 m/s)

v2 = 333 m/s

v3 = 425 m/s

v4 = 378 m/s

V2-4 av = 379 m/s

Cryo-compressed Hydrogen Storage.Test data validates lower burst energy of CcH2 vs. CGH2.

(v1 = 549 m/s)

v = 371 m/s

v = 421 m/s

v = 393 m/s

V2-4 av = 400 m/s

V2-4 av = 398 m/s

v4 = 394 m/s

v3 = 412 m/s

v2 = 375 m/s

(v1 = 483 m/s)

P06

P02/P07

P03/P08

P04/P09

P05/P10

P01

CGH2 (300K, 261bar)CcH2 (95K, 295bar)

Experiment 01 (Drucktank): P06-P10

-1

1

3

5

7

9

11

13

-1 1 3 5 7 9 11 13

Zeit / s

Dru

ck / b

ar

P06 [bar]

P07 [bar]

P08 [bar]

P09 [bar]

P10 [bar]Pmax ≈ 10 resp.

12.2 bar

Cryodrucktank (P06-P10)

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

0 2 4 6 8 10 12 14 16

Zeit / ms

Üb

erd

ruc

k / b

ar

P06

P07

P08

P09

P10

Pmax ≈ 2.4 resp.

3.3 bar

Four times higher pressure peak after CGH2 burst compared to CcH2 burst




vehicle storage


approach

Safety aspects



Cryo-compressed Hydrogen Storage.Conclusion.

Cryo-compressed hydrogen (CcH2) storage combines the advantages of gaseous (CGH2) and liquid (LH2) storage.

Core components of the BMW CcH2 storage have experimentally validated the requirements of high-density storage, rapid refueling (without H2 loss) and structural durability.

The CcH2 storage shows multiple advantages in terms of hydrogen safety.

The first level CcH2 storage system prototype has already been validated on test bench.

CcH2 fueling demonstration with hydrogen dispenser to be presented in 2011.

bmw hydrogen. ichs 2011. -...

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