ADAPTER, TESTING APPARATUS, BATTERY CELL, BATTERY, AND ELECTRIC APPARATUS

An adapter includes an adapting body and a valve body. The adapting body has a first mating portion and a second mating portion, where the first mating portion is configured to mate with an injection opening of a battery cell, the second mating portion is configured to mate with a gas detection apparatus, and a gas flow passage is constructed within an adapting body. The gas flow passage runs through the first mating portion and the second mating portion, and is configured for gas to flow from the injection opening to the gas detection apparatus.