Battery Failure Analysis and Characterization of Failure Types 2021

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Baker Engineering and Risk Consultants, Inc.
BESS Part 6:
Overview of Li-ion BESS Failures and Risk Management Considerations
By Roger Stokes February 4, 2022
This is the final article in a six-part series on Battery Energy Storage Systems (BESS), available for download here, which have examined:
1. Battery Failure Analysis and Characterization of Failure Types
2. BESS Frequency of Failure Research
3. Review of Fire Mitigation Methods for Li-ion BESS
4. Consequences of BESS Catastrophic Failure
5. Evaluation and Design of Structures to Contain Lithium-ion Battery Hazards
These articles explain the background of Lithium-ion battery systems, key issues concerning the types of failure, and some guidance on how to identify the cause(s) of the failures. Failure can occur for a number of external reasons including physical damage and exposure to external heat, which can lead to thermal runaway. Thermal runaway can also be triggered by numerous functional causes including overcharging, overloading, ageing, or design issues including internal component failures or short circuits.
We have also learned that the cause, likelihood and consequences of failure are dependent upon the many different designs and configurations of Lithium-ion batteries and associated systems. Forensic examination of a failed battery can determine cause and origin, although this can be difficult when there has been damage due to a major fire or explosion. However, other evidence, such as electronic data and video footage, can help piece together likely cause(s).
Lithium-ion battery technology is moving fast. At present, there is little data available on the reliability of BESS and as designs evolve to achieve higher charging rates, higher energy density, longer life, lower cost and improved reliability, any current data is likely to quickly become out of date. Nevertheless, data is being collected by various organizations and BakerRisk is working on developing statistical models to help our understanding of the likelihood of BESS failures.
Mitigation of fires involving Lithium-ion BESS was discussed in our third paper, which explained how the thermal runaway leads to the release of hot, flammable/toxic components. The high energy density of a typical BESS and the potential propagation/escalation of a runaway reaction incident presents a significant challenge in terms of specifying a suitable fire protection system. A water-based sprinkler system may not be effective in many situations and could make matters worse by causing electrical short-circuits. Water mist systems can be used, some of which use additives such as surfactants or gelling agents, but have limitations that need to be considered. While gaseous clean-agent systems can help extinguish or reduce the extent of the fire, they do not have sufficient cooling properties to prevent the escalation of a thermal runaway from a single cell or module/ rack, plus have the potential disadvantage of adding more
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