Abstract: A heat-dissipating device configured to cool the battery pack of an electric vehicle includes a coolant circulating pump and a tank. The coolant circulating pump is configured to engage with the one or more heat dissipation pipes of the electric vehicle and communicate with the one or more heat dissipation pipes. The tank is configured to contain coolant which includes phase change material. When cooling is required, for example during battery recharging, the coolant circulating pump is configured to inject the coolant in the tank into the one or more heat dissipation pipes via the coolant inlet, drive the coolant to flow in the one or more heat dissipation pipes, and take the coolant out from the one or more heat dissipation pipes via the coolant outlet to the exterior. A related electric vehicle and a related heat dissipation method are also provided.