1. The lithium-ion battery itself is of poor quality.
With the increase in the number of mobile phones, batteries have also become more diverse, with many manufacturers producing them. In pursuit of profit, some counterfeit and substandard batteries are produced. The most important component of a battery is the battery cell. Inferior batteries are of poor quality, have insufficient power, and falsely advertised capacity. Generally, a good battery has a smooth surface and moderate hardness, while a lower-quality battery has a very hard surface.
2. Using a non-original charger
The saying "a good horse needs a good saddle" applies here. No matter how good a lithium-ion battery is, if it's not charged with a good charger, it can easily swell. This is because the parameters of each charger are different, especially regarding overcharging, overcurrent, and overpower. Overcharging with a charger for too long can damage the lithium-ion battery pack.
3. Prolonged exposure to high temperatures
Ambient temperature is an important factor in extending the lifespan of lithium-ion battery packs, and it is also a major reason for lithium-ion batteries to bulge. High temperatures will cause the battery to heat up, so avoid direct sunlight and unplug the charger when it is fully charged.
