不同倍率下磷酸铁锂电池模组过充热失控特性研究

随着电化学储能技术在电力系统中的广泛应用,电化学储能技术的安全性越来越受到重视。文中以储能用磷酸铁锂电池模组(8.8 kW·h, 25.6 V,344 A·h)为研究对象,进行3次不同倍率(0.4C,0.5C,1C)的恒流过充试验,研究其在不同充电倍率条件下的过充热失控特性,并辅以starccm+软件进行热场仿真计算。结果表明,电池模组在额定充电倍率0.5C(172 A)和1C(344 A)下持续过充会发生起火,起火时间随着充电倍率增加而减少;充电倍率对磷酸铁锂电池模组过充行为特性影响较大,随着充电倍率的增加,热失控最高温度和峰值电压升高,过充测试时间随着充电倍率的升高而降低;不同充电倍率条件下,电池安全阀首次打开时的电压均为1.7倍额定电压,可以进一步研究以作为电池热失控预警参数。文中研究成果可为规模化储能用磷酸铁锂电池的安全性研究和电池管理系统(BMS)对过充故障的安全管理提供参考。

Overcharging and runaway characteristics of lithium iron phosphate battery modules at different rates

With the continuous improvement of electrochemical energy storage technology in power systems, the safety of electrochemical energy storage technology has received more and more attention. It takes the lithium iron phosphate battery module (8.8 kW·h, 25.6 V, 344 A·h) for energy storage as the research object, and conducts three constant current overcharge tests with different magnifications (0.4C, 0.5C, 1C) to study its advantages. The thermal runaway characteristics of overcharge under different charging rate conditions are supplemented by starccm+ software for thermal field simulation calculations. The experimental results show that the battery module catches fire under 0.5C (172 A) and 1C (344 A), and the fire-starting time decreases as the charging rate increased. Charging rate has a great influence on the thermal runaway behavior of lithium iron phosphate battery modules. With the increase of charging rate, the thermal runaway maximum temperature and peak voltage increase, and the overcharge process time decreases with the increase of charging rate. Under different charging rates, the charge voltage when the first battery safety valve opens are 1.7 times of the rated voltage, which is further regarded as a warning parameter for battery thermal runaway. A reference for the safety improvement of lithium iron phosphate batteries for energy storage and the battery management system (BMS) for the safety management of overcharge faults is provided.