Experimental study on the effect of ambient temperature and discharge rate on the temperature field of prismatic batteries

Abstract

Lithium-ion battery surface temperature is too high or too low and poor uniformity, not only affects the performance of the battery but is also prone to thermal runaway due to local overheating of the battery. In this work, by changing the discharge rate (0.5 C, 1 C, 1.5 C, and 2 C) and the ambient temperature (−20 °C, −10 °C, 0 °C, 15 °C, 25 °C, and 35 °C), the temperature change and distribution of large capacity and large size square lithium-ion power batteries under different experimental conditions were studied. The results show that the change in battery temperature is divided into three phases. I slow rise period, II fallback period, and III rapid rise period, and with the increase of discharge rate and the decrease of ambient temperature II stage will disappear, the battery temperature change gradually shows a linear increase. As the discharge rate increases and the ambient temperature decreases, both the cell temperature rise (ΔT) and temperature difference (Δt) will become larger. In addition, whether it is the increase of the discharge rate or the decrease of the ambient temperature, a large temperature difference is easily generated in the longitudinal axis direction of the lithium-ion battery during discharge, but the temperature difference generated in the lateral axis direction is just obvious in the lower ambient temperature.