Charging time is too long. . Every mobile phone (now) is made of lithium battery. . A certain amount of gas will be generated during use. . The longer the charging time, the more gas there is. When the internal pressure is increasing, the shell of the battery will be deformed. . If it is small, you can continue to use it. If it is large, you can consider changing the battery. Try to use the original charger for charging. . . . Misunderstanding of charging 1 It's not that the longer the charging time, the more durable the battery will be. 2 Not all the batteries will be used up before charging. 3 Fast charging is very harmful to the battery. Suggest using less.