Patent ID: 8387733

Claim:
A battery pack, comprising: a battery assembly including a plurality of stacked battery modules stacked together, each having a positive electrode and a negative electrode stacked together, and an electrolyte arranged between said positive electrode and said negative electrode; stacking direction of said plurality of battery modules being the same as stacking direction of said positive electrode and said negative electrode; a cooling passage allowing passage of a cooling medium, said cooling passage including an inlet passage provided along a first one of said plurality of battery modules arranged at one end in said stacking direction, through which said cooling medium is introduced, an outlet passage provided along a second one of said plurality of battery modules arranged at the other end in said stacking direction, through which said cooling medium is let out, a direction turning portion changing flow direction of said cooling medium introduced from said inlet passage and passing said cooling medium to said outlet passage, and a plurality of walls dividing said cooling passage into a plurality of passages are formed in said cooling passage, wherein among said plurality of passages, one positioned at a central portion of said cooling passage has a narrower width than another of the plurality of passages that is positioned at an end portion of said cooling passage.