Abstract: Provided is a battery pack including a rectangular parallelepiped first battery module having a first air intake surface, and a rectangular parallelepiped second battery module having a second air intake surface. A cooling air flow passage chamber is formed between the first air intake surface and the second air intake surface. The battery pack includes a one-side wall and an other-side wall that are interposed between the first air intake surface and the second air intake surface and seal the cooling air flow passage chamber from a third direction. The one-side wall and the other-side wall are formed so as to be able to expand and contract in a first direction while maintaining the cooling air flow passage chamber in a sealed state.

Abstract: Provided is a battery pack including a rectangular parallelepiped first battery module having a first air intake surface, and a rectangular parallelepiped second battery module having a second air intake surface. A cooling air flow passage chamber is formed between the first air intake surface and the second air intake surface. The battery pack includes a one-side wall and an other-side wall that are interposed between the first air intake surface and the second air intake surface and seal the cooling air flow passage chamber from a third direction. The one-side wall and the other-side wall are formed so as to be able to expand and contract in a first direction while maintaining the cooling air flow passage chamber in a sealed state.

Abstract: An inventive testing method is intended for testing a battery pack unit including: a battery pack including a plurality of cells electrically connected to each other; and a duct assembly through which a coolant is supplied to the cells of the battery pack. The testing method includes: a) charging the battery pack under predetermined conditions while supplying the coolant to the duct assembly; b) acquiring temperature information on the cells at predetermined time intervals during step a); and c) determining whether a difference between the highest and lowest ones of the temperatures of the cells measured at substantially the same time is equal to or greater than a predetermined reference temperature difference on the basis of the temperature information acquired in step b).

Abstract: An inventive testing method is intended for testing a battery pack unit including: a battery pack including a plurality of cells electrically connected to each other; and a duct assembly through which a coolant is supplied to the cells of the battery pack. The testing method includes: a) charging the battery pack under predetermined conditions while supplying the coolant to the duct assembly; b) acquiring temperature information on the cells at predetermined time intervals during step a); and c) determining whether a difference between the highest and lowest ones of the temperatures of the cells measured at substantially the same time is equal to or greater than a predetermined reference temperature difference on the basis of the temperature information acquired in step b).

Abstract: A voltage measurement device that measures battery voltages of a plurality of single batteries connected in series has: a first voltage detection unit that detects the battery voltages; a storage unit that stores error information relating to a detection error between a voltage detected by the first voltage detection unit and a voltage detected by a second voltage detection unit of higher detection precision but lower detection speed than the first voltage detection unit; and a correction unit that, on the basis of the error information stored in the storage unit, corrects the battery voltages detected by the first voltage detection unit.