A battery includes a battery module, a box, and an output electrode base. An output electrode is electrically connected to the battery module. The box includes a first beam, where an avoidance groove is formed on the first beam. The output electrode base includes a main body portion and a fastening portion that are connected to each other, where at least a part of the main body portion is accommodated in the avoidance groove, one end of the output electrode is fastened to the main body portion, and the fastening portion is disposed on a side that is of the first beam and that faces away from the battery module and is connected to the first beam. The output electrode base can be assembled by being staggered from a top of the first beam through the fastening portion of the output electrode base.