Why do lithium batteries need to add a protection board
Adding a protective plate to the battery is for user safety. Lithium battery has its safe discharge charge and overcurrent limit. The protection board is added so that these values do not exceed the safety range when using lithium batteries.
For example, the upper limit of the safety voltage of a lithium battery is 4.25V. If the battery protection board BMS is not added, it will always be charged when the charger without overcharge protection is used. As a result, the voltage of the lithium battery exceeds the safe voltage, and the battery will be charged. Safety accidents, fires and even explosions occurred. The role of the battery protection board is to stop charging after the battery is charged to the maximum voltage.
The principle of discharge and overcurrent detection is the same as that of charging voltage control. Therefore, the battery with the battery management system can control the lithium battery cell to work in the specified working environment. But charging, but not discharging, the charging protection voltage is generally 4.25V protection, and the discharge protection is generally 2.75V protection. The charging current can be within the maximum endurance range of the lithium battery, and the safety is greatly improved.