In the process of using new energy vehicles, I always hear the words "car battery balance" or "car balance battery". What does it mean? In short, it is a charging method that balances the characteristics of the battery. The power battery pack used by the car is not a "large single battery", but a module composed of many cells and a battery pack composed of multiple modules. It has been skipped at present. Module, the structure of directly forming groups of batteries (blade batteries).

The battery pack is composed of multiple lithium batteries, each of which has its own charge and discharge cut-off voltage. For example, the charge cut-off voltage of the 18650 battery is around 4.25V, and the discharge cut-off voltage is around 2.75V. Generally, as long as one lithium battery reaches the cut-off voltage, the charging and discharging process will be terminated for battery protection.

During the charging process, it is possible that none of the other lithium batteries has reached the charge cut-off voltage, and only one lithium battery has reached the charge cut-off voltage. But for the protection of the battery, the charging process will end. This is like the principle of a wooden barrel, because a "short board" causes the water storage capacity of the entire wooden barrel to be greatly reduced, and the unbalanced battery will cause a serious reduction in the cruising range.

During the discharge process, only one lithium battery may reach the discharge cut-off voltage first, and the remaining lithium batteries still have a lot of discharge capacity, but for protection, the discharge process will also be terminated.

When pure electric vehicles have severely reduced cruising range and weakened power, 4S shops usually use an equalizer to make a "car battery balance" for the vehicle. The goal is to balance the charge and discharge performance of all lithium batteries to the same level as much as possible, so that the battery pack can store more electrical energy and discharge more thoroughly during discharge.