In an article published in Power Electronic Tips and EE World Online (February 2020), learn how Li-ion battery pack designers like Inventus Power are increasing their safety focus and following a design strategy that emphasizes both prevention and mitigation of a thermal event.
The catastrophic failure of a battery pack in a thermal runaway process creates a dangerous situation even in single or small multi-cell packs, but in a medium or large format system (such as those used in burden carriers or utility vehicles for materials handling) with hundreds of cells, the potential for damage to equipment or harm to a nearby user is enormous. The energy released as heat from a cell undergoing thermal runaway must be diffused before heating any other cell in the module, but the concern for high margins of safety in these systems can lead to a high cost burden. In this article, Inventus Power analyzes construction and thermal mass characteristics to show how the other cells in the module dissipate heat. Thresholds for the total absorption of heat are established and a design approach is demonstrated for proper use of this approach to improve thermal event resilience at module level in medium and large format battery systems.