The performance of power battery is a significant factor affecting the overall quality of electric vehicles. To optimize the thermal management effect of battery pack, cold plate with wedge-shaped microchannels was proposed in this paper. On the basis of the models of the independent cold plate and the battery-cooling module, the effects of outlet aspect ratio, flow rate, and branching structure on the heat dissipation performance of the cold plate were studied at first. Afterwards, the effects of cooling surface, flow rate, and branching structure on the temperature distribution of the battery module were simulated. The results showed that the wedge-shaped channels provided a good cooling efficiency and surface temperature uniformity. When the wedge-shaped channel was used in thermal management of the battery module, the side-cooling method reduced the temperature difference of batteries by more than 35.71% compared with front cooling under the mass flow rate of 2 x 10(-5) kg/s. At a discharge rate of 3.5 C, the flow rate of 1 x 10(-4) kg/s controlled the battery temperature to within 45 degrees C, and the branching structure designed for the module successfully decreased the maximum temperature difference from 7.27 degrees C to 4.67 degrees C, which has been reduced by approximately 35.78%.