Adapter, testing apparatus, battery cell, battery, and electric apparatus

An adapter, comprising:

• an adapting body having a first mating portion and a second mating portion, wherein 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 the adapting body, the gas flow passage running through the first mating portion and the second mating portion and being configured for gas to flow from the injection opening to the gas detection apparatus;
• and
• a valve body constructed to be movably disposed on the adapting body and movable relative to the adapting body when controlled to switch between states of turning on and off the gas flow passage;
• wherein the gas flow passage comprises a first passage and a second passage, the first passage runs through the first mating portion, and the second passage runs through the second mating portion.