Why do some batteries need to be protected with a protective plate, and some not?

Adding a protective plate to the battery is for user safety. Lithium-ion battery has its safe discharge charge and overcurrent limit. The protection board is added so that these values u200bu200bdo not exceed the safe range when using lithium-ion batteries. For example, the upper limit of the safety voltage of a lithium-ion battery is 4.25V. If the board is not added, it will continue to be charged when using a charger without overcharge protection. It's like a person who is full, and you tell him to continue to eat. In the end, he will die, and the lithium-ion battery will also die. The purpose of the protection board is to stop charging when it is full. The principle of discharge and overcurrent detection is also the same. Therefore, the battery with the protection board can control the lithium battery cell to work in the specified working environment. 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 withstand range of the lithium-ion battery, and the safety is greatly improved. Putting a protective board on the battery will also limit the output current. Generally speaking, there are chips on the protection board, about 2A for a single chip, and about 4A for a dual chip. Many high-power devices in life, such as e-cigarettes, model airplanes, and electric cars, require high-current power supply. Because they are easily used violently (referring to excessive charging and discharging), the battery life is relatively low; at the same time, the battery is small and conventional high-power protection boards The volume is too large; the price of the protection board with ultra-low internal resistance is very expensive. In order to reduce the discharge loss and improve the cost performance, the protection board is generally not added, and the battery protection function is selected on the power receiving device. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.