Local hotspot characterization of an electric vehicle battery module using optical fiber thermometry

Abstract

Local hotspots of a 2s3p lithium-ion (Li-ion) battery module for electric vehicles were characterized using optical frequency domain reflectometry. A single optical fiber was routed along various locations throughout the module including cell surfaces, heatsinks, electrode tabs, and the bus bar connecting the two cell groups in series. Temperature distributions were probed under various constant current conditions from 0.5C to 3C. Results showed that temperature variations in excess of more than 16 °C were observed across the module. Distinct hotspots near the tabs and bus bar recorded temperatures up to 45 and 100 °C. Measurements were also made during a simulated urban driving cycle, which showed a markedly different temperature distribution than those of constant current conditions due to the constant cycling between charging and discharing.