Battery pack

A battery pack comprising:

• a plurality of battery stacks integrated by stacking a plurality of unit batteries;
• a fluid passage only disposed between separate and adjacent battery stacks, the fluid passage extending in a stacking direction of the plurality of batteries, where fluid flows for cooling the plurality of unit batteries, the battery stacks disposed adjacent to each other in an aligning direction perpendicular to the stacking direction;
• a fluid driver for circulating the fluid in the fluid passage;
• a heat conducting member group including a plurality of heat conducting members each thermally connected to at least one of an outer casing or an electrode terminal of one of the plurality of unit batteries, the plurality of heat conducting members being aligned in the stacking direction;
• a passage forming member that demarcates the fluid passage as an independent passage from an area near the outer casing of the unit batteries, and includes a partition wall for supporting the heat conducting members;
• a plurality of cooled parts of the plurality of heat conducting members that project into the fluid passage, surface areas of individual cooled parts in a central part of the heat conducting member group in the stacking direction being larger than surface areas of individual cooled parts in ends of the heat conducting member group in the stacking direction, and each cooled part having a greater surface area at a downstream end thereof than an upstream end thereof relative to the fluid flow, all of the cooled parts protruding from a same battery stack overlapping in the fluid passage in the stacking direction;
• and
• fins protruding from the cooled parts that overlap in the aligning direction.