What protection does the lithium battery protection board mainly do to the lithium battery?
1. Overcharge protection
Overcharge of lithium batteries is a common cause of explosion. Lithium batteries must work within the specified voltage range, otherwise there will be a safety hazard of explosion and fire.
For example, the conventional ternary lithium battery is 4.2V-4.35V, which belongs to the overcharge protection voltage; the conventional lithium iron phosphate battery is 3.65V, which belongs to the overcharge protection voltage.
When a lithium battery is charged, the lithium ions of the positive electrode move to the negative electrode and are embedded in the network structure of the negative electrode material. If the lithium ion battery is overcharged, it is easy to cause lithium in the negative electrode, causing lithium crystallization and piercing the diaphragm, which will cause electricity. The core is short-circuited, causing an explosion.
Therefore, when charging the lithium battery, an overcharge protection circuit must be added to protect the lithium battery from overcharge. The lithium battery protection board monitors the voltage of each string of the lithium battery pack. If the overcharge voltage is exceeded, the lithium battery protection board will cut off the charge to protect the lithium battery.
2. Over discharge protection
Overdischarge means overdischarge. When the lithium battery is discharged, the stored electric energy is gradually released, and the voltage drops slowly. When the voltage drops to a specified value, stop discharging and recharge to restore the battery's energy storage state. Continue to discharge below this specified value, that is, over-discharge, over-discharge may cause damage to the electrode active material, loss of reaction ability, and shorten the life of the lithium battery.
For example, the conventional ternary lithium battery is 2.5V-2.75V, which belongs to the over-discharge protection voltage; the conventional lithium iron phosphate battery is 2.0V, which belongs to the over-discharge protection voltage.
Therefore, the lithium battery must be equipped with an over-discharge protection circuit to protect the lithium battery from discharge. The lithium battery protection board monitors the voltage of each string of the lithium battery pack. If the overdischarge voltage is exceeded, the lithium battery protection board will cut off the discharge to protect the lithium battery.
3. Over current protection
Overcurrent protection is a protection method that causes the protection device to operate when the current exceeds a predetermined maximum value. When the current flowing through the protected original exceeds a predetermined value, the protection device is activated, and the time limit is used to ensure the selectivity of the action, so that the circuit breaker will trip or give an alarm signal.
Therefore, when the current in the lithium battery circuit exceeds the design value, for the protection of the lithium battery and electrical equipment, the lithium battery protection circuit activates the overcurrent protection and cuts off the internal circuit of the lithium battery for protection.
4. Short circuit protection
Protection for short-circuit faults caused by electrical short-circuiting of unequal-potential conductors in the power supply system. When the external positive and negative poles of the lithium battery are inadvertently short-circuited, for protection of the lithium battery, the lithium battery protection board starts short-circuit protection and cuts off the internal circuit of the lithium battery for protection.
5. Temperature protection
A type of protection based on the temperature change of the protected lithium battery as the basis for judgment.
When the lithium battery is overcharged or overcurrent, the temperature of the lithium battery will first rise sharply. When the temperature rises to the temperature protection value set by the protection board, the temperature protection is activated and the internal circuit of the lithium battery is cut off for protection.
The above are several protections for Benwei battery to organize lithium batteries.
