Battery Abuse Testing and Thermal Runaway Propagation

Thermal runaway (TR) propagation is an essential characteristic of larger lithium-ion battery fires. Cell- and module-level battery abuse tests have been conducted using large-format NMC pouch cells. In both test campaigns, heating was used to trigger TR. An electrical heater was used for the cell-level tests, and heat exposure to an external flame was used to trigger a cell-to-cell propagating TR in the modules. Cell surface temperatures were measured during both test campaigns to evaluate thermal runaway properties, including TR onset temperatures, TR max temperatures, and TR heating rates, as a function of local heating rates. The TR propagation characteristics in the modules were analysed based on the module’s temperature distribution and heat release rate. A comparison between the conditions during single-cell and full-module tests was conducted to evaluate their effects on TR and, ultimately, to determine whether cell tests are representative of the conditions during a passive propagation test or a real Lithium-ion battery fire scenario.