1. firstly, the manufacturing process is unqualified. If the electric vehicle market is mixed, many companies are prone to bulge due to the limited manufacturing level of lithium-ion batteries, uneven electrode coating and no air gap left for the batteries.
2. lithium ion battery pack overshoot. On the one hand, battery overshoot is easy to cause fire, on the other hand, it will also cause battery bulge. Battery overshoot will cause a large amount of heat in the battery, resulting in electrolyte decomposition and gasification, and the battery will bulge.
3. the charging current is too large. At present, many car owners refit batteries and electric vehicles without permission. In addition, some car owners buy cheap mismatched chargers. Batteries of different sizes have specified voltage and current. If the charging current is too large, the precipitation on the electrode plate will be too fast, resulting in insufficient chemical reaction, too high temperature, and untimely exhaust, the battery bulge will naturally occur.
4. The pressure of the safety valve is too high. People in the industry know that the electric vehicle battery is equipped with a safety valve to ensure safety. When the pressure in the electric vehicle battery rises, the safety valve will automatically open for pressure relief to ensure the balance of internal and external air pressure of the battery. If the safety valve can not be opened normally when the pressure in the lithium-ion battery pack rises, over time, due to the high pressure in the battery and the imbalance of internal and external air pressure, there will be bulges.
5. Mixed charger: some owners have more than one electric vehicle at home. When charging electric vehicles, they often mix them. For example, charging a 48 volt battery with a 60 volt charger or charging a high-voltage battery with a low-voltage charger for a long time will cause the battery to bulge.
6. the charging time is too long. In general, the time for the battery to be fully charged is 12 hours. However, some friends often forget about it after plugging in the charger for the electric vehicle. They have been charging for one night, even more than 24 hours. Such a long-time charging method will definitely cause great damage to the battery, and it is inevitable that the lithium-ion battery is bulging.
7. using the fast charging method, although the electric vehicle has brought us great travel convenience, there are also times when there is no electricity on the way, so sometimes we can only use the fast charging method. However, this method is very easy to cause the lithium-ion battery pack bulge.