How to charge new energy vehicles is a concern for many car enthusiasts. Today, I will provide a systematic and in-depth explanation of how electric vehicles should be charged, what is best for batteries, and how to maximize battery life.
irstly, it is necessary to establish a concept that lithium batteries are not afraid of frequent charging. Every deceleration and kinetic energy recovery during driving is to charge the battery. Frequent charging of the battery has no effect, but if the battery remains fully charged, the voltage inside the cell will be high. The higher the temperature, the more chemical reactions will occur, causing the battery's charge to permanently decay. So the more times the battery is fully charged, the more obvious the battery decay will be.
There are only two common types of electric vehicle batteries on the market, one is ternary lithium, and the other is lithium iron phosphate. The corresponding charging methods are different. First of all, let's talk about this lithium iron phosphate battery. The consistency of the battery pack of lithium iron phosphate is not as good as that of ternary lithium. Some cells discharge quickly, while others discharge slowly. Over time, the capacity difference between cells becomes large. Cells with low battery capacity will decay faster, Even easily damaged. Moreover, lithium iron phosphate batteries have a characteristic that regardless of whether your battery level is low or high, the voltage of the battery is the same. Therefore, it cannot estimate its remaining capacity by detecting the voltage of the battery like ternary lithium. Therefore, for lithium iron phosphate battery packs, the battery management system BMS cannot detect the specific remaining capacity of each individual cell, and it cannot balance the power between each cell in real time. So the only way to balance lithium iron phosphate batteries is to fully charge all the monomers, so that the charge between the monomers is balanced. Therefore, lithium iron phosphate batteries need to be fully charged regularly. Although the decay of a fully charged battery may be faster, if the individual cells of the battery pack are more imbalanced, it will have a greater impact on the overall lifespan of the battery pack. Moreover, lithium iron phosphate inherently has a longer cycle life, and fully charged batteries have little effect on its entire cycle life.
Speaking of ternary lithium batteries, the charging method is relatively simple, which is shallow charging and discharging. It is best to cycle back and forth between 30% and 80%, which is the slowest decay rate. It is not recommended to charge ternary lithium batteries frequently because. The more fully the battery is charged, the higher the concentration of lithium ions, making it easier for lithium ions to fuse with each other and generate this lithium crystal, which is metallic lithium. This reaction is irreversible. As the number of lithium ions decreases, the amount of charge carried decreases, resulting in a decrease in the battery's capacity. If the quality of ternary lithium is not good, lithium crystal branches will be generated when fully charged and left for a long time, which will penetrate the separator and cause a short circuit between the positive and negative poles, leading to self ignition of the battery. This is why some electric vehicles equipped with ternary lithium batteries will burn themselves when parked there. On the one hand, the battery quality itself is not good, and on the other hand, overcharging can also have a significant impact. With the advancement of battery production technology, it is now possible to avoid the formation of irregular and sharp lithium crystals, and the probability of short circuits and spontaneous combustion has been greatly reduced. However, it is still recommended not to place ternary lithium batteries fully charged.
In summary, the charging methods for the two types of batteries are as follows: for lithium iron phosphate batteries, they must not be left empty as it may damage the battery. It is best to fully charge them in daily life; Triple lithium batteries should not be placed at full charge. When using shallow charging and discharging in daily life, the battery level should circulate between 30% and 80%, and even if fully charged, it should be used immediately. This can maximize the battery life of lithium batteries.READ MORE!!
Post time: Dec-12-2023