Liquid cooling is a crucial method for mitigating runaway battery thermal management systems (BTMS). Among the various factors that influence the effectiveness of liquid cooling, the coolant inlet temperature (CIT) of the coolant plays a crucial role. This study investigates the impact of CIT on BTMS under low flow velocity conditions (0.1 m/s). Under the condition of constant flow rate and a fixed battery heat generation model, the three CIT levels (280 K, 290 K, and 300 K) were analyzed. At CIT levels of 280 K, 290 K, and 300 K, the peak battery temperatures were 303 K, 309 K, and 314 K, respectively, while the minimum temperatures (at the cold plate interface) were 280 K, 290 K, and 300 K, respectively. Results indicate that in the designed cold-plate structure, lowering CIT enhances local heat extraction near the cooling plate but exacerbates thermal inhomogeneity within the battery module. We suggest selecting a CIT of 290 K to achieve the dual objectives of mitigating thermal stress risk and ensuring effective heat dissipation.