a coolant cycle system comprising a coolant cycle frontend radiator, a power assembly heat dissipation system, a battery pack heat dissipation system, a primary path water pump, a bypass water pump, and a valve bank system;

a refrigeration cycle system connected to the primary path water pump of the coolant cycle system;

wherein the power assembly heat dissipation system and the battery pack heat dissipation system share the refrigeration cycle system and the coolant cycle frontend radiator by using the primary path water pump, the bypass water pump, and a combination of the valve bank system; and

a control device controls a heat dissipation mode of the power assembly heat dissipation system and a heat dissipation mode of the battery pack heat dissipation system based on an ambient temperature and an inlet coolant temperature of a power assembly, wherein each heat dissipation mode is natural heat dissipation or refrigeration heat dissipation, the natural heat dissipation is heat dissipation using the coolant cycle system, and the refrigeration heat dissipation is heat dissipation using the refrigeration cycle system,

wherein that the control device controls the heat dissipation mode of the power assembly heat dissipation system and the heat dissipation mode of the battery pack heat dissipation system, when the ambient temperature is lower than a first preset threshold and the inlet coolant temperature is within a second preset range, the control device controls the power assembly heat dissipation system to use the refrigeration heat dissipation, and controls the battery pack heat dissipation system to use the natural heat dissipation, and wherein

the first preset threshold is a temperature range during normal working of a battery pack, and the second preset range is a required range of the inlet coolant temperature during high-torque high-output working of the power assembly.