The comprehensive performance of a lithium battery thermal management system (BTMS) is critical to battery capacity and service life. To improve the system performance after module packaging, this study proposes a novel liquid cooling plate structure incorporating a double-channel Tesla valve. First, numerical simulations were conducted to compare the cooling performance of same-side versus opposite-side outlets, as well as to evaluate the double-channel Tesla valve against the original Tesla valve and a straight channel design. Then, an orthogonal experimental design was used to identify four key parameters with significant impact on overall performance. A Kriging response surface model was then established to describe the relationship between design variables and objective functions, followed by multi-objective optimization using the non-dominated sorting genetic algorithm (NSGA-Ⅱ). Results show that the opposite-side inlet-outlet configuration provides superior cooling performance. Under counterflow conditions, the double-channel Tesla valve reduced the maximum battery temperature ( T _max) by 0.67 ℃ compared with the straight channel, while the pressure drop (Δ p) was 117.67 Pa and 437.39 Pa lower than those of the original Tesla valve and the straight channel, respectively. After optimization, the improved Tesla valve channels reduced Δ T and Δ p by 1.52% and 11.16%, respectively, while increasing the cooling plate thermal performance factor (CTPF) by 4.81%. These findings provide a valuable reference for the structural design and optimization of liquid cooling systems for power batteries.