A battery pack case, characterized in that, comprising: a case body, comprising an accommodating chamber, a side wall of the case body being provided with a maintenance port communicating with the accommodating chamber; a cover plate assembly, detachably connected to an outer surface of the side wall and being capable of opening or closing the maintenance port, the cover plate assembly comprising a cover plate and an outer gasket stacked with each other; wherein the cover plate comprises a first concave portion formed by being recessed in a thickness direction of the cover plate and a first limiting portion formed by surrounding an outer periphery of the first concave portion, the cover plate abuts against the outer surface by the first limiting portion to form a first receiving chamber disposed surrounding the maintenance port between the first concave portion and the outer surface, and the outer gasket is disposed in the first receiving chamber and is closely contact with the first concave portion and the outer surface, characterized in that, the battery pack case further comprises a fixing assembly connected to an inner surface of the side wall, wherein the fixing assembly comprises a connecting portion penetrating through the side wall and the cover plate assembly in the thickness direction, and the cover plate assembly is detachably connected to the outer surface via the connecting portion, the fixing assembly further comprises a fixing plate disposed opposite to the cover plate assembly, the fixing assembly is connected to the inner surface via the fixing plate, and the connecting portion is connected to the fixing plate, and the connecting portion comprises a connecting rod and a locking cap connected to each other, one end of the connecting rod is connected to the fixing plate, and the other end of the connecting rod passes through the side wall, the outer gasket and the cover plate in the thickness direction and is detachably connected with the locking cap. a case body, comprising an accommodating chamber, a side wall of the case body being provided with a maintenance port communicating with the accommodating chamber; a cover plate assembly, detachably connected to an outer surface of the side wall and being capable of opening or closing the maintenance port, the cover plate assembly comprising a cover plate and an outer gasket stacked with each other; wherein the cover plate comprises a first concave portion formed by being recessed in a thickness direction of the cover plate and a first limiting portion formed by surrounding an outer periphery of the first concave portion, the cover plate abuts against the outer surface by the first limiting portion to form a first receiving chamber disposed surrounding the maintenance port between the first concave portion and the outer surface, and the outer gasket is disposed in the first receiving chamber and is closely contact with the first concave portion and the outer surface, characterized in that, the battery pack case further comprises a fixing assembly connected to an inner surface of the side wall, wherein the fixing assembly comprises a connecting portion penetrating through the side wall and the cover plate assembly in the thickness direction, and the cover plate assembly is detachably connected to the outer surface via the connecting portion, the fixing assembly further comprises a fixing plate disposed opposite to the cover plate assembly, the fixing assembly is connected to the inner surface via the fixing plate, and the connecting portion is connected to the fixing plate, and the connecting portion comprises a connecting rod and a locking cap connected to each other, one end of the connecting rod is connected to the fixing plate, and the other end of the connecting rod passes through the side wall, the outer gasket and the cover plate in the thickness direction and is detachably connected with the locking cap.