Study of lithium-ion battery module's external short circuit under different temperatures

External short circuit has a severe influence on lithium battery's performance. Currently, a huge study has focused on the single battery's short circuit. However, cells are often interconnected into a module in real applications. There are many possibilities that external short circuit of a single cell has huge impact on the other cells in a battery module. In this research, experiments were conducted under different conditions (single lithium-ion battery, 3 lithium-ion battery modules, 9 lithium-ion battery modules) at different ambient temperatures (30, 40, and 50 degrees C) and different state of charge [SOCs (80%, 90%, 100%)] The temperature of the battery surface (positive electrode, middle) rose during external short circuit. The variation of the battery temperature was analyzed. Then, the variation of battery performance parameters under external short circuit conditions was studied. All lithium-ion batteries were divided into two groups, one being an external short circuit and the other being not short-circuited externally. As a result, when the lithium-ion battery was short-circuited externally, the battery temperature rose rapidly to the maximum temperature that the battery can rise. The highest temperature caused by external short circuit appeared in the case of a single battery. The higher the SOC, the faster the battery temperature rose. In the cycle charge and discharge, the rate of decay of the battery after an external short circuit was twice faster than that of a normal battery. As the temperature increased, the rate of battery capacity decayed further. Under normal circumstances, the attenuation of the battery to 80% required about 350 cycles. The life of the battery after the external short circuit was shortened by more than half, and when the temperature rises, even only about 100 cycles were required.

Automated summary

External short circuit has a significant impact on other cells in a battery module, leading to increased battery temperature and accelerated performance decay. The lifespan of the battery is significantly shortened after an external short circuit.