How to extend the service life of lithium iron phosphate battery

The iron phosphate polymer battery pack of new energy vehicles is usually composed of many batteries. There are two key indicators for investigating batteries: one is the capacity of the battery, which can be regarded as the capacity of a bowl, and the other is the state of charge of the battery. Commonly known as remaining power, hereinafter referred to as SOC) can be regarded as the content of water in the bowl. For example, when a 50mL bowl is filled with 25mL of water, the SOC at this time is 50%. The capacity of the core is basically the same as the SOC. Only in this state can all the batteries be fully charged and vented synchronously. The consistency is good. Generally, the stored or factory SOC is maintained at about 10-20%. When the iron phosphate polymer battery is stored or shipped from the factory, the SOC is about 10% to 20%. However, as the service life and the number of recharges increase, the inside of the iron phosphate polymer battery will change unpreventably. The capacity or SOC of each battery cell will change. The phenomenon of unevenness occurs. According to the principle of the wooden barrel, the amount of water that a flat wooden barrel can hold is determined by the short board, and the capacity of the iron phosphate polymer battery pack is also determined by the short board. The barrel short board effect indicates that all cells are charged and discharged synchronously. In the case of inconsistent cell capacity or SOC, as long as one cell is fully charged or emptied, other cells cannot continue to charge and discharge, because if you continue to charge and discharge, it will Leading to the overcharge and overdischarge of the battery cell with a small capacity, the lithium inside the battery cell becomes a polymer element and the precipitation leads to the destruction of the internal structure of the battery cell, which reduces the life of the iron phosphate polymer battery pack, and in the worst case it may cause the battery cell Fire and other dangerous events, so the small-capacity or SOC battery is equivalent to the short wooden board inside the iron phosphate polymer battery, which leads to the reduction of the total energy stored in the iron phosphate polymer battery pack and shortens the available cruising range. This is The barrel principle inside the iron phosphate polymer battery pack. Iron phosphate polymer battery charge cut-off (the battery with small capacity will be automatically protected when it is full) What is the reason for the difference between the batteries? As the saying goes, if you want to treat a disease, it is important to find out the cause of the disease. There are generally three differences between the batteries: the SOC is the same, the capacity is inconsistent. This state is similar to the edge of the bowl with a gap. Originally, it can hold 50ml of water, but now it can only hold 40ml. , Otherwise it will leak out from the gap. At this time, the small capacity first full and empty is the bottleneck of the capacity of the entire iron phosphate polymer battery pack. The following figure is an example, the three batteries with different capacities before charging are all at 50%, SOC is The current power is half of the full power, so the iron phosphate polymer battery pack meets a condition, the capacity is consistent, and batteries of different capacities cannot be mixed. The SOC of the iron phosphate polymer battery is the same, but the capacity is inconsistent. After charging the same amount of power, the battery cell with a small capacity reaches the fully charged state. At this time, the battery cell cannot be continuously charged, because if it continues to charge, the fully charged cell will be overcharged. Long-term overcharging may even lead to dangerous events such as battery fire. Iron phosphate polymer batteries with inconsistent capacity. When these cells are discharged in the state of charge, the cells with small capacity will also first reach the empty state. At this time, the discharge cannot be continued because if the discharge continues, the empty cells will be over-discharged for a long time. Discharge will cause damage to the internal structure of the battery. Disclaimer: Some pictures and contents of articles published on this site are from the Internet. If there is any infringement, please contact to delete.