Effect of Temperature Distribution on the Predicted Cell Lifetimes for a Plug-In Hybrid Electric Vehicle Battery Pack 2022-01-0712

Monitoring and preserving state-of-health of high-voltage battery packs in electrified road vehicles currently represents an open and growing research topic. When predicting high-voltage battery lifetime, most current literature assumes a uniform temperature distribution among the different cells of the pack. Nevertheless, temperature has been demonstrated having a key impact on cell lifetime, and different cells of the same battery pack typically exhibit different temperature profiles over time, e.g. due to their position within the pack. Following these considerations, this paper aims at assessing the effect of temperature distribution on the predicted lifetime of cells belonging to the same battery pack. To this end, a throughput-based numerical cell ageing model is firstly selected due to its reasonable compromise between accuracy and computational efficiency. Subsequently, experimentally measured temperature and C-rate profiles over time in a driving mission are considered for three cells of the high-voltage battery pack of a commercially available plug-in hybrid electric vehicle. Obtained results suggest that due to temperature distribution in the high-voltage battery pack, the predicted lifetime for the hottest cell might be as low as 61% compared with the coldest cell of the pack. Importance and advancement of monitoring and managing the state-of-health of the single cells of an electrified vehicle battery pack might be fostered in this way thanks to the proposed study.