Comprehensive comparison of different structural thermal management systems for lithium-ion battery module based on electrochemical–thermal–aging and conjugate heat transfer coupled model

In this study, we extend the analysis of typical BTMS structures—traditionally focused on temperature-based thermal parameters—by incorporating electrochemical indicators such as SOC and SOH. Four structurally distinct BTMS configurations were evaluated in terms of fluid flow, thermal behavior, and electrochemical performance. Since the outlet locations of the Z - and U-type BTMSs are opposite to each other, they exhibit symmetric physical characteristics. Owing to their asymmetric geometries, pronounced flow concentration was observed, with maximum flow rates of 56.38% in the Z-type and 50.60% in the U-type. Consequently, the third cell in the Z-type exhibited a temperature range of 32.09–37.41 °C, while the twelfth cell in the U-type exhibited a temperature range of 31.81–36.17 °C. These cells also showed maximum RUL advantages of 52 and 44 cycles, respectively. The J-type BTMS, which featured two outlets, demonstrated improved flow uniformity with a minimum flow deviation of 3.48%, resulting in a maximum cell-to-cell temperature difference of 1.32–2.84 °C. Compared with the Z -, U-, and I-type BTMSs, this corresponded to improvements of 79.11–116.43%, 48.14–66.42%, and 93.94–141.31%, respectively, in terms of the maximum temperature difference. In contrast, the I-type BTMS showed an extreme flow concentration, with 90.4% of the total flow directed to the second and third manifolds. This led to a maximum temperature difference of 6.69 °C among battery cells, exceeding the recommended limit of 5 °C, indicating the I-type BTMS as a primary candidate for optimization.