Battery Surface Temperature Measurement Correction for an Accelerating Rate Calorimeter with Sapphire Optical Access

Upcoming legislation towards zero carbon emission is pushing the electric vehicle as the main solution to achieve this goal. However, electric vehicles still require further battery development to meet customer’s requirements as fast charge and high energy density. Both demands come with the cost of higher heat dissipation as lithium transport and chemical reaction inside the battery need to be performed faster, increasing the joule effect inside the battery. Due to its working principle, which guarantees an adiabatic environment, an accelerating rate calorimeter is used to study thermal phenomena in batteries like a thermal runaway. However, this equipment is not prepared to work with optical access, which helps to study and to comprehend battery surface distribution and other thermal aspects. This paper aims to show a methodology to correct temperature measurement when using a thermographic camera and optical access of sapphire in an accelerating rate calorimeter. The problem comes from the warm environment inside the calorimeter that heats the sapphire window and emits radiation for the thermographic camera, masking the battery surface temperature measurement. For this reason, the paper presents how this problem affects temperature measurement and how to overcome this problem with the methodology described using a thermocouple on the battery surface.