The retarding effect of liquid-cooling thermal management on thermal runaway propagation in lithium-ion batteries

Thermal runaway (TR) of an lithium-ion battery pack is investigated under laboratory conditions. The experi-mental battery pack consists of 10 18,650-type lithium-ion batteries connected in parallel and with a serpentine channel liquid-cooling thermal management system (TMS). The effect of the applied liquid-cooling TMS with different coolant flow rates (0 L/h, 32 L/h, 64 L/h and 96 L/h) on the TR propagation in the battery pack is analyzed, and the results indicate that the TMS is capable of preventing TR propagation. It is examined the eventual relation between TR prevention and the flow rate. The rate of TR in the batteries is almost random for lower values of the coolant flow rate (0 L/h, 32 L/h and 64 L/h), but for the coolant flow rate of 96 L/h, TR propagation can be effectively prevented. It is also found that the high-temperature electrolyte ejected from the positive side of the TR battery can rapidly spread to the adjacent batteries and trigger instantly their own TR. This is the leading mechanism yielding the TR propagation in the battery pack. Heat conduction and radiation, especially when the positive sides of the batteries are largely covered by the current connectors, play a minor role in the TR propagation. These findings may prove useful in designing lithium-ion battery packs with appropriate TMS strategies.