A Wireless Battery Temperature Monitoring System for Electric Vehicle Charging

Thermal monitoring during charging increases the safety and efficiency of Electric Vehicles (EVs) batteries. Up to now, no thermal sensing solutions are able to perform temperature sensing for each battery cell in the EV due to the cost, deployment complexity, and/or safety reasons. In this paper, a complete wireless thermal monitoring system for EV battery charging surveillance is presented. The designed sensing device is wireless, fully passive, with small feature size, and low-cost thus can be deployed on a large scale for cell-level battery temperature sensing. The maximum reading distance of the device is >5 m in the ambient, with a sensing precision of +/- 1.5 degrees C (3 sigma) from -20 to 80 degrees C. The whole system is validated in-house using a 18650-36V-4.4A Li-ion battery cell to track its temperature change when being charged at different C-rates.