Dynamic impact tests to characterize the crashworthiness of large-format lithium-ion cells

Abstract

In order to gain a better understanding of the crashworthiness of lithium-ion cells, a test-setup for dynamic impact and crush tests has been designed. An experimental study was carried out using prismatic automotive cells comprising increasing levels of manufacturing quality and specific energy made of lithium nickel manganese cobalt oxide as the cathode active material. Different loading scenarios and more than four orders of magnitude of deformation rates were applied to specimens at fully charged state. The presented work describes the test program, the experimental setup and an objective evaluation method, which finally allows for a detailed summary of the observed mechanical behavior. A distinct strain-rate dependence of hardening, failure parameters, and compressibility of the cells is found. No significant dependence on cell type and state of charge could be observed. The results constitute essential new insights into the material behavior of EV battery cells during a crash event.