A battery module, comprising: a plurality of batteries, which are arranged side by side; and a fixing frame, which is disposed around the plurality of batteries, the fixing frame comprises two composite end plates and two side plates, the composite end plates and the side plates are alternately disposed around the plurality of batteries, wherein each of the two composite end plates comprises: a rigid substrate, which has a first surface and a second surface that are opposite in a thickness direction of the rigid substrate, the first surface being disposed facing the plurality of batteries; and a rigid connecting plate, which is made of the same material as the side plates and is fixedly connected to the side plates by welding, wherein the rigid connecting plate comprises a connecting portion and a hook portion that is bent toward the connecting portion, the rigid substrate comprises a positioning groove which is shaped to match the hook portion, the positioning groove extends in a height direction of the rigid substrate, the hook portion is inserted into the positioning groove of the rigid substrate along the height direction to connect the rigid connecting plate to the rigid substrate, the connecting portion is located on the second surface, the rigid connecting plate is connected fixedly with the side plate via the connecting portion, and a material of the rigid connecting plate is different from that of the rigid substrate, wherein the number of the rigid connecting plate is two, and the respective hook portions of the two rigid connecting plates are oppositely disposed. a plurality of batteries, which are arranged side by side; and a fixing frame, which is disposed around the plurality of batteries, the fixing frame comprises two composite end plates and two side plates, the composite end plates and the side plates are alternately disposed around the plurality of batteries, wherein each of the two composite end plates comprises: a rigid substrate, which has a first surface and a second surface that are opposite in a thickness direction of the rigid substrate, the first surface being disposed facing the plurality of batteries; and a rigid connecting plate, which is made of the same material as the side plates and is fixedly connected to the side plates by welding, wherein the rigid connecting plate comprises a connecting portion and a hook portion that is bent toward the connecting portion, the rigid substrate comprises a positioning groove which is shaped to match the hook portion, the positioning groove extends in a height direction of the rigid substrate, the hook portion is inserted into the positioning groove of the rigid substrate along the height direction to connect the rigid connecting plate to the rigid substrate, the connecting portion is located on the second surface, the rigid connecting plate is connected fixedly with the side plate via the connecting portion, and a material of the rigid connecting plate is different from that of the rigid substrate, wherein a rigid substrate, which has a first surface and a second surface that are opposite in a thickness direction of the rigid substrate, the first surface being disposed facing the plurality of batteries; and a rigid connecting plate, which is made of the same material as the side plates and is fixedly connected to the side plates by welding, wherein the rigid connecting plate comprises a connecting portion and a hook portion that is bent toward the connecting portion, the rigid substrate comprises a positioning groove which is shaped to match the hook portion, the positioning groove extends in a height direction of the rigid substrate, the hook portion is inserted into the positioning groove of the rigid substrate along the height direction to connect the rigid connecting plate to the rigid substrate, the connecting portion is located on the second surface, the rigid connecting plate is connected fixedly with the side plate via the connecting portion, and a material of the rigid connecting plate is different from that of the rigid substrate, wherein the number of the rigid connecting plate is two, and the respective hook portions of the two rigid connecting plates are oppositely disposed.