基于热传递仿真的热电池激活阶段热特性

热电池激活依靠内部热源熔化绝缘固态电解质到高离子电导率熔融态。基于多物理场耦合分析软件（COMSOL）建立某热电池二维模型，进行激活阶段热传递仿真研究。以自定义热源函数模拟烟火系统放热过程，设置温度探针在电堆中部第7组单体电池及临近组件中，计算得到热电池温度分布、单体电池温度曲线和电解质熔化相变。以固态电解质熔化连接正负极作为热电池激活标志，预测最短激活时间，并对2个热电池进行激活测试以验证预测结果。建立引燃条内置式热电池模型以研究引燃条位置对激活时间的影响。研究结果表明：电堆端部温度较高，利于补偿放电期间的热耗散，集流片具有抵御热冲击的作用，探针温度短时维持在560 ℃；热电池激活时间预测值约为45 ms，实测值为42 ms和47 ms，表明模型和预测方法具有较高精度；引燃条内置式热电池激活时间缩短为30 ms。

Thermal Characteristics of Thermal Batteries during Activation Based on Heat Transfer Simulation

The activation of a thermal battery (TB) depends on the internal heat source to melt insulating solid electrolyte to highly ionic conductive melten state. A 2D model of a thermal battery is developed to simulate the heat transfer during TB activation based on multiphysics coupling software COMSOL.The heat releasing process of a pyrotechnic system is simulated with the user-defined heat source function. The temperature probes are set in the seventh unit cell and adjacent components at the center of TB stack. Temperature distribution, temperature curves of unit cell, and melting phase change are calculated.The time when the solid electrolyte melts enough to connect the cathodes and anodes is taken as the symbol of TB's activation to predict the shortest activation time. Two TBs are tested to verify the predicted results. Furthermore, an igniting tape built-in TB model is developed to study the influence of igniting tape's position on the activation time. The results show that the temperatures at the ends of TB stack are higher to compensate for heat dissipation during discharge. The current collectors can withstand thermal impact. The probes maintain at 560 ℃ in a short time. The predicted activation time is about 45 ms, the test activation times are 42 ms and 47 ms，indicating the model and prediction method are of high accuracy. The activation time of the built-in TB reduces to 30 ms.