What causes lithium ion batteries to explode?

Battery problems in brand mobile phones themselves are relatively rare, the battery itself problems appear in the refurbished or second mobile phone.In order to save costs, mobile phones or refurbished machines tend to choose inferior batteries with lower costs in mobile phone configuration.These batteries have low cost, excessive impurities, poor design process, and high risk of self-explosion.
Cell overcharge for a long time: long time charging state, overcharge, overcurrent will also lead to high temperature and high voltage, the occurrence of hidden dangers.Lithium-ion batteries in special temperature, humidity and poor contact conditions may be instantaneous discharge and a large number of current, spontaneous combustion or explosion.
Battery short circuit: when the mobile phone is in the state of high temperature, or hit, metal friction and other circumstances, may cause battery short circuit, explosion.

Charging leads to battery explosion: playing with the phone while charging or charging while playing will lead to longer charging time. A long time of charging will cause the temperature of the phone to rise and it is more likely to explode.
The charger does not fit the battery: the general mobile phone has the original charger.The wrong type of charger can easily cause a battery accident.The iPhone only accepts the original charger, which greatly reduces the chance of the battery exploding.
High temperature: high temperature refers to the battery internal heat reached the limit, long time charging, high temperature irradiation, baking are easy to cause the battery temperature is too high.In the south of China, ordinary families will use electric ovens in winter. Many people like to play with mobile phones while baking in electric ovens, which is also very dangerous.

Thermal runaway: Lithium-ion batteries are at risk of exploding because of a process called thermal runaway in the battery's internal reactions.Thermal runaway is a positive energy feedback cycle: rising temperatures cause the system to get hotter, which in turn makes the system hotter.The above reasons, such as battery short circuit, excessive ambient temperature, frequent overcharging, unauthorized modification of the shell, etc., will cause the thermal runaway of the lithium ion battery, which may eventually cause fire or explosion.