BATTERY COOLER

A battery cooler comprises a refrigerant filling chamber, a refrigerant inflow passage, and a refrigerant outflow passage. The battery cooler is arranged to be sandwiched between side surfaces of a plurality of unit cells forming an assembled battery. Refrigerant is charged in the refrigerant filling chamber. The refrigerant filling chamber is sandwiched between the opposed unit cells and arranged at a position where the refrigerant filling chamber receive heat from the unit cells. The refrigerant inflow passage allows a refrigerant condensed by an external condenser to be flowed in the refrigerant filling chamber. The refrigerant inflow passage is connected to a lower portion of the refrigerant filling chamber. The refrigerant outflow passage allows refrigerant vaporized in the refrigerant filling chamber due to the heat of the unit cells to be flowed out toward the condenser. The refrigerant outflow passage is connected to an upper portion of the refrigerant filling chamber. The refrigerant filling chamber has opposed wall surfaces in contact with the side surfaces of the unit cells arranged at its both sides, and at least one joint part joining partially and mutually the opposed wall surfaces so as to suppress expansion and deformation of the refrigerant filling chamber caused by the pressure of the refrigerant. An outflow side wall surface rises from a bottom surface of the refrigerant filling chamber toward a connection part of the refrigerant outflow passage with respect to the refrigerant filling chamber. The outflow side wall surface is provided with an inclined surface directed downward from a horizontal direction.