Battery pack

A battery pack comprising:

• a plurality of batteries each including a discharge valve that opens when an internal pressure becomes higher than a set pressure;
• and
• a case configured to house the batteries, wherein
• the case includes an integrated structure formed of a resin case made of plastic and a metal plate,
• the resin case includes a heat radiation opening that is closed by the metal plate, and
• the metal plate includes a plurality of smoke discharge holes in a closed region where the heat radiation opening of the resin case is closed, wherein
• the case includes a first case and a second case disposed opposite to each other in an arrangement direction and directly connected to each other to together define a closed structure,
• the first case comprises a first resin case and a first metal plate,
• the first resin case including a first resin peripheral wall disposed along an outer peripheral edge of the first metal plate and extending in the arrangement direction, and
• the first metal plate including a first metal peripheral wall extending from the outer peripheral edge of the first metal plate in the arrangement direction, and having a distal end thereof enclosed within the first resin peripheral wall,
• the second case comprises a second resin case and a second metal plate,
• the second resin case including a second resin peripheral wall disposed along an outer peripheral edge of the second metal plate and extending in the arrangement direction, and
• the second metal plate including a second metal peripheral wall extending from the outer peripheral edge of the second metal plate in the arrangement direction, and having a distal end thereof enclosed within the second resin peripheral wall,
• wherein the first resin case defines the heat radiation opening, and the first metal plate has the plurality of smoke discharge holes defined therein,
• wherein the first metal peripheral wall and the second metal peripheral wall are stacked to each other at connecting portions of the first and second resin peripheral walls, and
• at said connecting portions, the first metal peripheral wall and the second metal peripheral wall overlap each other in an overlap direction perpendicular to the arrangement direction without the first metal peripheral wall and the second metal peripheral wall touching each other, wherein portions of the first resin peripheral wall and the second resin peripheral wall intervene between the first metal peripheral wall and the second metal peripheral wall in the overlap direction.