Insights into thermal failure features under varied heating powers are significant for the safe application of lithium ion batteries. In this work, a series of experiments were conducted to investigate the thermal failure features of fully charged lithium iron phosphate battery by means of copper slug battery calorimetry. Batteries were given a total quantity of external heat (16 kJ) under various heating powers (20 - 200 W). Battery temperatures, onset time of venting, mass loss and internal heat generation were measured and analyzed. Results show onset times of venting and thermal runaway both decrease exponentially with increasing heating power. Heat generation of batteries under different heating powers is in the range of 10.38 kJ - 15.07 kJ. The battery maximum temperature and heat generation do not increase monotonically with heating power, but reach the highest at 100 W. Furthermore, the experiments at 20 W with continuous heating were carried out to contrast with the experiments results of fixed heating quantity. It is found that battery maximum temperature, mass loss and heat generation are all higher under continuous heating. These encouraging results could enhance our understanding of thermal failure features and provide references for the safety design and thermal failure propagation prevention in battery module.

洞察各种加热功率下的热失效特性对于锂离子电池的安全应用具有重要意义。在这项工作中，进行了一系列实验，以通过铜电池量热法研究充满电的磷酸铁锂电池的热失效特征。在各种加热功率（20-200 W）下，为电池提供的外部热量总量（16 kJ）。测量并分析了电池温度，排气开始时间，质量损失和内部发热。结果表明，随着热功率的增加，排气和热失控的开始时间均呈指数下降。在不同加热功率下电池的发热范围为10.38 kJ-15.07 kJ。电池的最高温度和发热不会随加热功率单调增加，但在100 W时达到最高。此外，还进行了20 W连续加热的实验，以与固定发热量的实验结果进行对比。发现在连续加热下电池的最高温度，质量损失和发热都更高。这些令人鼓舞的结果可以增进我们对热失效特征的理解，并为电池模块的安全设计和防止热失效传播提供参考。