A battery cooling system includes a battery cooling flow path, a first inlet and outlet portion of the battery cooling flow path, a second inlet and outlet portion of the battery cooling flow path, an inflow-side three-way valve, an outflow-side three-way valve, a first supply flow path configured to connect a first outlet of the inflow-side three-way valve to the first inlet and outlet portion, a second supply flow path configured to connect a second outlet of the inflow-side three-way valve to the second inlet and outlet portion, a first discharge path configured to connect the first inlet of the outflow-side three-way valve to the second inlet and outlet portion, and a second discharge path configured to connect the second inlet of the outflow-side three-way valve to the first inlet and outlet portion.