1. 18.08.2005Helfried Rybin 1 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Safety Demands for Automotive Hydrogen Storage Systems Helfried Rybin Risk Management E-Mail: helfried.rybin@magnasteyr.com

2. 18.08.2005Helfried Rybin 2 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Content Introduction Demands for design and reliability Methods to minimize risks of design failures Validation Summary and outlook

3. 18.08.2005Helfried Rybin 3 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Safety demands for automotive hydrogen storage systems Future hydrogen powered vehicles operated by not specially trained people Fuel storage systems for vehicles require a fail-safe design strategy Materials and accessories used shall be compatible with hydrogen Source: BMW Group / Munich, Germany

4. 18.08.2005Helfried Rybin 4 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Fail-safe design strategy for liquid hydrogen fuel tanks Design Redundant systems for safety, i.e. if one system fails, another system has to secure the hydrogen fuel tank This philosophy is reflected by the following regulation and standards: Draft UN ECE Regulation revision 14 and 14 add. 1 keeping the probability of critical failures at an acceptable level risk of hydrogen powered vehicles may not exceed the risk of conventional vehicles Draft ISO 13985 Liquid Hydrogen – Land vehicle fuel tanks

5. 18.08.2005Helfried Rybin 5 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Fail-safe design strategy for liquid hydrogen fuel tanks Reliability System reliability is statistically proven over the complete life cycle Criteria for this reliability are reflected in: IEC 61508: Functional safety of electrical/electronic/programmable electronic safety-related systems about functional safety of safety-related systems looks at the whole safety life cycle classification into safety integrity levels

6. 18.08.2005Helfried Rybin 6 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Fail-safe design strategy for liquid hydrogen fuel tanks Requirements and concept Realisation Operation and Maintenance Safety life cycle

7. 18.08.2005Helfried Rybin 7 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Methods to minimize risks of failures in an early design phase Failure mode and effect analysis (FMEA)   is an instrument for avoiding risks and for reducing cost for development and manufacturing of products  researches the design for possible failures due to initiate activities to avoid or reduce the risk of this failure  is a method which promotes the interdisciplinary team work at an early stage  delivers a documented expertise

8. 18.08.2005Helfried Rybin 8 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Lifetime estimation by finite element analysis simulations pressure due to vaporizing hydrogen expansion of materials during thermal cycling external loads due to mechanical vibrations fatigue oriented analysis of stress-time histories includes both physical tests and simulations illustrative animations of the deformation behaviour and the resulting stresses damage distribution of the cutting plane Stress plot of the support structure Methods to minimize risks of failures in an early design phase Rain flow Analysis

9. 18.08.2005Helfried Rybin 9 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Safety demands for automotive hydrogen storage systems

10. 18.08.2005Helfried Rybin 10 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Functional tests The basic test program includes: verification of valves and sensors at their operating temperatures leak rate measurement verification of the time for refuelling validation of the liquid level indication quality of the thermal insulation Non-destructive functional testing on a liquid hydrogen test bench:

11. 18.08.2005Helfried Rybin 11 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Testing of the MLI for flammability Reason of this test: Loss of vacuum causes an condensation of oxygen  atmosphere with liquid oxygen in the vacuum space Risk of an explosion  The MLI must not be flammable to avoid a fire accident Impact test: mixture of liquid nitrogen and liquid oxygen with minimum 50% liquid oxygen The impact energy of 79 J/cm² must not cause an ignition of the MLI 20 samples are required Destructive tests

12. 18.08.2005Helfried Rybin 12 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Crash and skid test Destructive tests Dynamic vibration test Statistic values for estimating the lifetime behaviour Inner tank: at ambient temperature at cryogenic temperature (filled with liquid hydrogen) In order to examine the: connection between body and liquid hydrogen fuel tank the suspension of the inner tank at high external loads Source: BMW Group / Munich, Germany

13. 18.08.2005Helfried Rybin 13 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Vacuum loss test Destructive tests Bonfire test Proves the design of the pressure relief devices in case of a degraded thermal insulation. Following points are observed: tank pressure and temperatures hydrogen blow-off behaviour hydrogen blow-off time The average temperature in the space 10 mm below the fuel tank shall be at least 863 K Thermal autonomy of the liquid hydrogen fuel tank shall be at least 5 minutes Verification of the design of the pressure relief devices Source: Energie Technologie GmbH / Munich, Germany Source: BAM / Berlin, Germany

14. 18.08.2005Helfried Rybin 14 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Safety demands for automotive hydrogen storage systems Summary Fuel storage systems for vehicles require a fail-safe design strategy Methods to minimize risks of design failures in an early design phase FMEA Lifetime estimation by use of finite element analysis Non-destructive and destructive tests for verification of the fuel system Outlook to inspire public confidence in this new technology decrease costs by the standardization of legal requirements for hydrogen internationally

15. 18.08.2005Helfried Rybin 15 www.magnasteyr.com AUTOMOBILENTWICKLUNG / ENGINEERING Safety demands for automotive hydrogen storage systems Thank you for your attention Helfried Rybin Risk Management E-Mail: helfried.rybin@magnasteyr.com