In an embodiment, a battery module is configured for insertion into a battery module compartment of an energy storage system. The battery module includes a first exterior plate configured with a male joining section, a second exterior plate that is adjacent to the first exterior plate and configured with a female joining section, wherein the first and second exterior plates are joined together via the male and female joining sections without welding. In an example, by joining the first and second exterior plates (e.g., and optionally, other exterior plates of the battery module as well) without welding, problems associated with heat from a welding process as well as spatters and dirt accumulation at battery cells of the battery module can be reduced or avoided.