Exploring heat release rates in large lithium-ion batteries for trains
The uptake of large lithium-ion batteries to power rolling stock is increasing. These batteries are crucial to decarbonising sections of the rail network where electrification is not feasible. However, they introduce new risks.
If a lithium-ion traction battery is damaged, it might experience thermal runaway. If this breaches its containment, this could inflict irreparable damage to the train, harm staff and passengers, and cause network disruption. Although this is a very rare occurrence, we need to be prepared to reduce the severity of the consequences from such an event.
This can be achieved by ensuring that standards cover suitable mitigations against the risks introduced by traction batteries.
The research investigated lithium-ion battery heat release data. It modelled their effect on fire barriers and recommend improvements to fire barrier standards.
Limited data is available for the heat release rates of large batteries. Despite this, the research was still able to identify key trends using the available data. One such trend showed that vertical battery pack arrangements have higher heat release rates than horizontal ones.
Fire models were validated and used to test theoretical fire barriers. Recommendations were then produced to clarify factors influencing fire hazards and barrier effectiveness.
The research recommendations will be used to enhance rail industry standards.
Thermal runaway of a traction battery could irreparably damage rolling stock and infrastructure. This could cost millions to repair or replace. Enhancing fire barrier standards will help prevent asset loss and provide added resilience for evacuation times.
Clear robust requirements at the design stage means that new rolling stock will be equipped with adequate fire barriers, saving retrofitting costs.