Under high-rate operating conditions, the risk of thermal runaway in power batteries increases, highlighting the critical role of thermal management structural design. Current liquid cooling systems suffer from high flow resistance, while lightweight battery enclosures face constraints due to vehicle safety requirements. This paper achieves optimal flow channels through channel reconstruction and fluid dynamics analysis. Iterative topology optimization is applied to directionally optimize microchannels, while composite materials replace metal components to overcome weight reduction limitations. Simulation results demonstrate that the redesigned mechanical structure reduces power consumption while enhancing flow field temperature uniformity and mechanical stiffness, providing a reliable engineering paradigm for battery protection.