1. Poor battery protection circuit or no protection circuit: This situation often occurs in mobile phones with detachable batteries. Many users like to buy relatively cheap non-original batteries. These batteries usually cut corners in order to maximize profits. The protection circuit of the battery itself is prone to problems, resulting in cell expansion. For lithium-ion batteries, the cell will explode when it expands to a certain extent.
2. Poor performance of the charger: It should be the most common case that the charger causes battery problems. In many cases, the user may not pay much attention to the choice of mobile phone charger, and often take a charger to charge. These chargers may be cheap chargers sold on the street, without a complete protection circuit system, or chargers for household tablet products. Their charging current is likely to be relatively large, and occasionally the charging problem is not serious. However, if they are used for a long time, it is likely that the battery will expand.
In particular, some users like to play while charging, so that the mobile phone is in a high temperature environment for a long time. Continuous floating charging at high temperature will lead to side reactions in the electrolyte. Doing so for a long time will seriously affect the battery life, and the expansion problem is also easy to occur.
3. Mobile phone is not used for a long time: If the mobile phone is not used for a long time, the battery will also expand. This is because the battery voltage will drop to below 2V after long-term storage, and chemical reactions will occur inside, resulting in lithium battery gas drum. This is also the reason why many friends will find the cell phone battery drum when disassembling old mobile phones. So if you want to store the battery for a long time, the most reliable way is to periodically charge it to the semi-charged state.
