A battery includes: a unit cell including an electrode layer, a counter electrode layer facing the electrode layer, and a solid electrolyte layer disposed between the electrode layer and the counter electrode layer; an electrode current collector in contact with the electrode layer; a counter electrode current collector in contact with the counter electrode layer; and a seal disposed between the electrode current collector and the counter electrode current collector. The unit cell is disposed between the electrode current collector and the counter electrode current collector. The seal includes at least one protrusion protruding toward the solid electrolyte layer, and at least part of the at least one protrusion is in contact with the solid electrolyte layer.