Battery module shell

The utility model discloses a battery module shell. The battery module shell comprises an upper cover plate, a bottom plate and two side plates, the side edges of the upper cover plate and the bottomplate comprise a plurality of first welding parts, and the side edges of the side plates comprise second welding parts; wherein the first welding part comprises a first extending section, a second extending section and a third extending section which are connected in sequence, and height difference exists among the first extending section, the second extending section and the third extending section; the second welding part protrudes out of the side plate and is bent towards the direction of the first welding part, one end of the second welding part abuts against at least one part of the second extending section, and a gap is formed between the second welding part and the first extending section. According to the battery module shell, a directional discharge structure is designed in the welding area of the upper c