The battery energy storage system (BESS) is widely used in the power grid and renewable energy generation. With respect to a lithium-ion battery module of a practical BESS with the air-cooling thermal management system, a thermofluidic model is developed to investigate its thermal behavior. The thermal model for a single battery is established and experimentally validated first, and then the thermofluidic model for this battery module is developed based on the single battery thermal model and validated by experimental data also. Simulations are performed considering the practical frequency regulation condition and some hypothetical situations with unexpectedly high heat generation rates. Thermal behaviors of the battery module under different conditions are carefully analyzed. Results show that the fans-on forced air convection cooling reduces the maximum temperature by 0.4 K and makes the maximum temperature appear in a different battery of the BESS module compared with the natural air convection cooling. Especially, the temperature monitoring strategy is studied. Due to technical and cost constraints, only a limited number of temperature monitoring points can be set and the temperature that can be monitored is the battery surface temperature or some connecting bars’ surface temperature. The rationality of the locations of different temperature monitoring points is analyzed. The obtained results clearly indicate that enough caution must be paid when setting the temperature monitoring points in practical BESSs. The bad temperature-monitoring strategy may largely underestimate the maximum temperature (by as much as 3 K under the normal frequency regulation condition, and probably much larger under harsh working conditions) in the BESS and fails at reflecting the thermal status of the BESS.

电池储能系统（BESS）广泛用于电网和可再生能源发电。对于具有空气冷却热管理系统的实际BESS的锂离子电池模块，开发了一种热流体模型来研究其热行为。建立单电池的热模型并首先进行实验验证，然后基于单电池的热模型开发此电池模块的热流体模型，并通过实验数据进行验证。考虑到实际的频率调节条件和一些假想的情况以及高的发热量，进行了仿真。仔细分析了电池模块在不同条件下的热行为。结果表明，与自然空气对流冷却相比，带风扇的强制空气对流冷却将最高温度降低了0.4 K，并使最高温度出现在BESS模块的不同电池中。特别是，研究了温度监控策略。由于技术和成本的限制，只能设置有限数量的温度监控点，可以监控的温度是电池表面温度或某些连接条的表面温度。分析了不同温度监测点位置的合理性。获得的结果清楚地表明，在实际的BESS中设置温度监控点时必须格外小心。