Lithium battery pack equalization treatment

What is the purpose of the equalization treatment of lithium battery packs? The application of lithium battery packs in the market and in various fields is not uncommon. The most important link in the charging and discharging process of lithium battery packs is the equalization link. Equalization has the function of equalizing voltage for lithium battery packs. , So as to achieve the effect of full charge and discharge of the battery pack capacity, so that the battery pack can exert the maximum effect.

What is the equalization treatment of lithium battery packs?

Lithium battery packs are composed of multiple batteries. Since the batteries are independent individuals, there will be some slight differences. After the combination is welded, the direction and length of the connecting piece and the influence of the welding process will be affected. Increasing the generation of differences, each charge and discharge will increase the value of individual differences. When the value reaches a certain height, it will eventually lead to partial overcharge and overdischarge of the cell. This situation will cause damage to the cell and ultimately As a result, the entire set of lithium batteries cannot work effectively.

Equalization of lithium battery packs can solve this problem. When a single string of lithium-ion batteries has a large numerical difference, the BMS controls the equalization voltage of the battery, which can maximize the service life of the lithium battery pack. To put it bluntly, the balance is to maintain all lithium battery packs in all normal categories to ensure overall safety.

The balance link is to ensure that the input and output of the lithium battery pack are reasonable to each lithium battery, so that it can be used reasonably and effectively without damage. At present, the two most common equalization methods for lithium battery packs are energy-consumption equalization and transfer-energy equalization.

Lithium battery equalization technology means that after the lithium batteries are grouped, the overall performance of all batteries in the battery pack is brought to the same level through human intervention. The purpose is to ensure that the performance of the lithium battery pack can be fully utilized and to ensure the safety of the battery during use .

Equalizing charging method of series lithium battery pack

1. Add a parallel equalization circuit to each single battery to achieve the shunting effect. When a battery is fully charged first, the equalization device can prevent it from overcharging and convert the excess energy into heat, and continue to charge the under-charged battery.

2. Before charging, each cell is discharged to the same level through the same load one by one, and then constant current charging is performed to ensure that the cells are in a more accurate equilibrium state.

3. Timing, sequencing, individual battery detection and uniform charging. When the lithium battery pack is charged, it can be ensured that each battery will not be overcharged or discharged, that is, it is in a normal working state.

4. Using the time-sharing principle, through the control and switching of the switch components, the extra current flows into the battery with a relatively low voltage to achieve the purpose of balanced charging. This method is more efficient, but the control is more complicated.

5. Take the voltage parameters of each battery as the object of balance to restore the same voltage of each battery. During equalizing charging, the capacitor is alternately connected to two adjacent batteries through the control switch, accepts the charging of the high-voltage battery, and then discharges to the low-voltage battery until the voltages of the two batteries tend to be the same. This method is better, but it is mainly used where the number of batteries is small.

6. The single battery module performs charging management on each single battery separately according to the set program, and automatically disconnects after the charging is completed. This method is relatively simple, but the cost is larger and the system volume is increased.

Once the lithium-ion battery cell loses constant, it will directly cause the entire group of lithium-ion batteries to fail, so in order to reduce this probability. The use of lithium battery pack equalization technology is still very necessary.