A battery module is formed by arranging multiple unit cells in a module case. Each of the module cases is segmented into a battery chamber where multiple unit cells are housed and an exhaust passage where exhaust gas from the unit cells is released outside the module case through an exhaust port. The arranged multiple battery modules are mounted on a module mounting member and the module mounting member is fixed to a pack case. The module mounting member includes an exhaust duct for passing therethrough the exhaust gas discharged from the exhaust passage.
