Case for Secondary Battery, and Secondary Battery, Module, and Device Comprising Same

Provided is a case for a secondary battery accommodating an electrode assembly, including a lower member, an upper member disposed above the lower member, and a sealing part to which the lower member and the upper member are fused to seal the case. The sealing part includes a first sealing part in which an electrode terminal connected to the electrode assembly exists and a second sealing part which is a remaining area except for the first sealing part. The case includes a polymer resin layer formed on an edge of the first sealing part and a reinforcing layer surrounding the polymer resin layer. The case for a secondary battery has improved water resistance, insulation and mechanical properties. Also provided is a secondary battery, a module, and a device including the same.