To guide gas generated from a power storage body cell constituting each module to a desired place and to exhaust the gas to the outside without connecting each module constituting an energy storage system to an exhaust path provided separately.

The coupling structure is used for configuring an energy storage system by coupling modules M each consisting of a power storage body cell contained in a case. A space Mf in the case Ma constituting one of adjoining modules M, M and the space Mf in the case Ma constituting the other of adjoining modules M, M are interconnected through a coupling member J which couples the adjoining modules M, M.