The utility model relates to a field of battery cooling technique provides battery pack, including tray, group battery and liquid cooling pipe, the group battery is installed on the tray, and the group battery includes outer frame and a plurality of battery cell, and the bottom of outer frame is provided with the installation cavity, and liquid cooling pipe part at least holds in the installation cavity. During operation, above -mentioned battery pack pass through rational arrangement of liquid cooling pipe, make the interior liquid cooling pipe of installation cavity can take away battery cell's heat to effectual heat pipe reason is carried out to power battery to the realization, makes the group battery keep the temperature uniformity, the prior art that compares, and it has avoided owing to adopt air -cooling structure the problem that cooling efficiency is low, can't satisfy security requirements, has avoided leading to owing to adopt liquid cooling structure that the structure is complicated, the problem of the group battery of can't freely arranging.