Experimental study on the preheating efficiency of an aluminum‐rich ternary lithium‐ion battery using constant‐voltage preheating method

Abstract

Summary The performance of the lithium‐ion battery decreases significantly at low temperature and it generally requires preheating before usage. Based on the constant‐voltage‐discharge(CVD) preheating method, a series of experimental studies on the preheating efficiency (PE) and energy consumption ratio (ECR) of an aluminum‐rich high discharge rate ternary lithium‐ion battery at low temperature were carried out. The influences of discharge voltage, state of charge (SOC), ambient temperature on the PE, and ECR were investigated in details. The effect of CVD on battery aging was also investigated. The experimental results showed that CVD preheating had a good preheating performance. Under the same experimental conditions, the PE increases with the decrease of discharge voltage and the increase of ambient temperature, but decreases with the decrease of SOC. The ECR decreases with the discharge voltage decreasing and ambient temperature increasing, but increases with the SOC decreasing. The results also showed that energy for external work (Q1) and energy released to the external environment (Q3) takes up a large proportion of total energy under different preheating parameters during the preheating process, which is a possible way to improve the CVD efficiency. At last, the battery aging is found to increase with the preheating voltage decreasing. After 300 preheating cycles, the maximum reduction of battery capacity is about 5.64% for the 2.3 V CVD case.