The role of lithium battery protection board for electric vehicles. The electric vehicle lithium battery protection board is the bridge between the power battery and the outside world, which determines the utilization rate of the battery, and its performance is very important to the cost and safety of the electric vehicle. Because the lithium battery of electric vehicle is multi-cell and multi-string, the function of the protection board is required to be strong. In addition to the most basic overcharge and over-discharge short-circuit protection, it also draws on the problem of battery balance, which will increase the battery balance circuit.

The role of lithium battery protection board for electric vehicles

Protect the lithium battery from being over-discharged and over-charged, and also limit the short-circuit current. When the lithium battery discharges to a very low voltage, it will stop. The standard is limited to 2.75V. If the lithium battery voltage is low, it will not be able to resume charging and damage the battery. At least the damage makes the capacity small. The charging limit voltage is 4.25V. If it is too high, it will damage the battery or explode during charging. When accidentally short-circuited, the protection circuit is activated and the output is turned off to limit the high-current generation of high-temperature and high-pressure gas to the lithium battery and cause an explosion accident

The protection function of lithium battery is usually completed by a protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the battery cell and the charging and discharging circuit at all times under the environment of -40°C to +85°C. Current, timely control the on and off of the current loop; PTC prevents severe damage to the battery in high temperature environments.

The protection board for lithium batteries of electric vehicles has many protection functions and functions, as follows:

①Overcharge protection, overdischarge protection, overcurrent and short circuit protection.

②Current protection: It is mainly embodied in the working current and overcurrent to disconnect the switch MOS to protect the battery pack or load.

③Short-circuit protection: Strictly speaking, it is a voltage-comparative type of protection, that is, it is directly turned off or driven by voltage comparison, and does not go through extra processing.

④Temperature protection: When the temperature sensor reaches the temperature threshold and the protection delay is reached, the control circuit controls to turn off the charge and discharge MOS tube to stop charging and discharging.

⑤Equalization protection: When a certain string of the lithium battery reaches the equilibrium voltage, the control circuit turns off the charging circuit, and when a certain string of the battery exceeds the equilibrium voltage, the control circuit releases the voltage.

When the electric vehicle lithium battery is discharged to a very low voltage, it will stop. The standard is limited to 2.75V. If the lithium battery is completely out of low voltage, the battery cannot be recharged and the battery is damaged. At least the damage makes the capacity small. The charging limit voltage is 4.25V. If it is too high, it will damage the battery or explode during charging. When accidentally short-circuited, the protection circuit is activated, shutting off the output, and limiting the high current to produce high temperature and high pressure gas to the lithium battery, causing an explosion accident.

Does the lithium battery pack of electric vehicles need to use a protective board?

The application of lithium batteries is so extensive, so people are paying more and more attention to the safety of lithium battery packs for electric vehicles, and lithium battery protection boards have become important. Everyone knows the role of lithium battery pack protection board, the most basic three points: prevent overcharge, prevent overdischarge and prevent the harm caused by short circuit. Therefore, lithium battery pack electric vehicles will use protective plates.

If we find that the temperature of the battery itself rises while using the lithium battery of an electric vehicle, it is probably caused by the short circuit of the positive and negative electrodes. If there is a lithium battery pack protection board, if the positive and negative electrodes are short-circuited, the protection board will understand the power failure , So there will be no heat generation. On the contrary, if there is no lithium battery protection board, the battery will heat up abnormally.