The Cause of Lithium Ion Battery Bulge in Electric Vehicle

1. Poor quality of lithium ion battery chargers

At present, due to the price war, the quality of the charger has been declining all the way. The use of inferior boards, refurbished or inferior components, heating, and inaccurate parameter drift have made the charging voltage limit out of control, resulting in the deformation of the battery shell caused by the extrusion of the gas inside the lithium ion cell pack, which results in the bursting of the battery shell and even the explosion.

2. Long charging time of the lithium ion battery

Some users do not have the concept of time to charge, and they think they plug it in and it will stop when it's fully charged, so they don't care. Some people even charge it for two days and nights before they remember it. After a long time of charging, the life of lithium-ion battery packs of electric vehicles will be threatened. Overcharging will cause the internal temperature of the battery to rise, and the electrolyte to decompose, producing gas, which makes the battery bulge.

3. Internal failure of lithium ion battery

The internal battery plate group has quality problems, micro short circuits, lack of acid leakage, water shortage, resulting in thermal control and producing a lot of gas. And the safety valve can not release the gas, the exhaust valve hole is blocked, so that the internal gas pressure increases leading to the deformation of the battery shell, which causes the battery bulge, even to burst.

4. Reasons for the charger used for lithium ion battery

Forgetting to bring a charger, borrowing one casually, or misusing several electric car-sized chargers in the family is common. Each electric vehicle battery brand has its own interface, current value, different electric motors allowed charging voltage. Different charging current, charging time and charging efficiency will be different. The battery capacity is small, and the current that can be passed by the charger is large, which leads to overcharging of the battery, resulting in thermal runaway, decomposition of the electrolyte, and generation of a large amount of gas, causing the battery to be charged.

The above is the analysis of the reasons for the bulge of lithium ion cell in electric vehicles. The general charging process is as follows: Constant current charging at the set current. When the battery voltage rises to 4.20V, changing to constant voltage charging and keeping the charging voltage at 4.20V. At this point, the charging current gradually decreases, when the current drops to the set charging current 1/10, the charging end. This is the process of charging a normal lithium ion battery. If the lithium ion cell exists in a smart device, its charging mode will be controlled by the smart device software.

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