Battery pack cooling system of electric vehicle

The invention provides a battery pack cooling system of an electric vehicle. The battery pack cooling system of the electric vehicle comprises a battery pack, a water tank, a pipeline and a water pump, wherein the pipeline is connected with the water pump, the water tank and the battery pack to form a first water circulation loop and a second water circulation loop; the battery pack cooling system further comprises a controller; the controller is used for acquiring temperature parameters of the battery pack and controlling one or both of the first water circulation loop and the second water circulation loop to cool the battery pack according to different temperatures of the battery pack. Compared with the prior art, the battery pack cooling system provided by the invention can select proper cooling modes at different temperatures according to a power battery, can effectively control the power battery to operate well in a proper temperature range, and saves energy.