The reasons for which the battery can swell are usually few. The most common reasons for the swelling of power supplies: falsification, natural aging and wear, long-term storage in a discharged state, improper storage (in wet rooms and in rooms with high or low temperature), dropping or charging by non-original chargers. Thanks to the statistics, the methods of which I found at assignment.essayshark.com/statistics-help.html we can say that the cases of bloating as a result of factory marriage are the rarest. An inflated or deformed battery should not be used, it should be replaced.