Insulating sandwich housing structures for the thermal management of battery packs

Modern electric vehicle battery thermal management systems provide sophisticated means to control the temperature of its battery cells within the optimal temperature range. This is crucial as Lithium-Ion battery cells result in reduced lifespans if exposed to temperatures above 50°C. On the other hand, temperatures below 10°C lead to a reduced capacity and with respect to electric vehicles in reduced driving ranges. The OPTEMUS project therefore develops a thermal insulating battery module housing that thermally disconnects the battery cells from the ambient temperature, providing a more stable temperature profile and more efficient thermal management of the battery. Different housing materials and designs have been developed to provide thermal insulating properties while also withstanding mechanical forces. Based on a concept module design of Fraunhofer LBF, two different fiber reinforced plastic sandwich structures have been manufactured with insulating foam cores and analyzed with respect to their cellular structures and resulting thermal properties. The cellular structure was detected three-dimensionally via computer tomography analysis. The manufactured sub-module housings were tested in a climatic chamber at -10°C and compared to a benchmark housing design based on aluminum as construction material. Results showed that the cell temperatures decrease 250 to 400 % slower using foam core sandwich structures as housing material compared to an aluminum housing while providing large scale manufacturability via the injection molding process.