A case, a battery, a power consuming device, and a method for assembling a case are provided. The case includes a first case body, an accommodating groove, a sealant, and a second case body. The first case body is provided with an opening. The accommodating groove is provided in a peripheral direction of the opening. The sealant is accommodated in the accommodating groove. The second case body is provided with a peripherally-arranged joint part. The joint part is configured to extend into the accommodating groove and be joined with the sealant when the second case body covers the opening, so as to form a sealed connection between the first case body and the second case body. The accommodating groove can limit the sealant, the sealant does not shift in the accommodating groove, and a sealing failure is less likely to occur, thus ensuring the sealing performance of the sealant.