The current efforts of design optimization, including load resistance, topology, and parasitic energy loss analysis, mainly focus on the thermoelectric modules operating under constant temperature difference. By contrast, these mechanisms contribute to the output parameters of thermoelectric modules under constant heat flux is still ambiguous. Here, by choosing the PbTe as a case study, COMSOL Multiphysics software to establish the three-dimensional numerical model is employed. The quantitative analytical method for heat transfer verifies that the reduction in hot side temperature of modules is dominated by Peltier effect, leading to the deviation of practical optimal ratio between load resistance and internal resistance (R_L/R_in) from the traditional maximum power point (MPP). Moreover, the increased thermoelectric leg height significantly enhances the average figure of merit zT_avg of P/N thermoelectric materials, triggering an improvement of optimal R_L/R_in and output performance. Through manipulating the leg cross-sectional area ratio (A_p/A_n) to ∼0.82, a high efficiency of ∼14.5% is achieved for ideal contacted PbTe-based thermoelectric modules at a temperature difference of 500 K. Furthermore, the critical role of parasitic energy loss on performance evolution are recognized. Eventually, the different types of module are established to verify the effectiveness of above theory. The present findings provide universal guidance for advancing the efficiency of thermoelectric modules operating under constant heat flux.

目前的设计优化工作，包括负载电阻、拓扑结构和寄生能量损耗分析，主要集中在恒温差下工作的热电模块上。相比之下，这些机制对恒定热通量下热电模块的输出参数的贡献仍然不明确。这里以PbTe为例，采用COMSOL Multiphysics软件建立三维数值模型。传热定量分析方法验证了组件热侧温度的降低主要受Peltier效应的影响，导致负载电阻与内阻实际最佳比值（ R _L /R _in ) 来自传统的最大功率点 (MPP)。此外，增加的热电腿高度显着提高了 P/N 热电材料的平均品质因数zT _{avg ，引发了最佳}R _L / R _in和输出性能的改善。通过操纵腿的横截面积比 ( A _p / A _n) 到 ~0.82，理想接触式 PbTe 基热电模块在 500 K 的温差下实现了 ~14.5% 的高效率。此外，还认识到寄生能量损失对性能演变的关键作用。最终建立了不同类型的模块来验证上述理论的有效性。目前的研究结果为提高在恒定热通量下运行的热电模块的效率提供了通用指导。