Lithium iron phosphate battery fast charging -Lithium - Ion Battery Equipment

Is the fast charging method of lithium iron phosphate battery better than that of ternary lithium? -Lithium - Ion Battery Equipment

If new energy vehicles want to be truly close to the experience of traditional gasoline vehicles, shortening charging time, improving cruising range and charging convenience are unavoidable topics. Dr. Wang Shengwei, head of the fast charging project of CATL New Energy Technology Co., Ltd. (CATL), said that the "superconducting electronic network" and "fast ion ring" technologies developed by CATL are a perfect combination, and the lithium iron phosphate fast charging core has been developed into a set. With 4C high-rate fast charging, 100% charging of pure electric buses can be completed in 15 minutes.

Recently, Wang Shengwei gave a speech analyzing the principles and characteristics of fast-charging lithium batteries, and introduced the maintenance methods of CATL and the progress of fast-charging lithium batteries.

In principle, the bottleneck of fast charging of batteries is the negative electrode. Common chemical systems will produce by-products at the negative electrode during fast charging, which affects the cycle and stability of the battery core. Once the lithium ions are blocked in the negative electrode, it is very dangerous, but as long as the lithium ions enter the interior of the graphite, there will basically be no problem. Therefore, CATL developed "fast ion ring" technology to create a highway network on the surface and inside of graphite so that lithium ions can be quickly embedded anywhere in the graphite.(Lithium - Ion Battery Equipment)

"It can achieve both lithium ion density and fast charging, which is like building a ring highway to alleviate traffic congestion. 'Fast ion ring' graphite has this mechanism. We have shipped hundreds of millions of mobile phones. It is reliable. Sex has been verified." Wang Shengwei introduced.

Is lithium iron phosphate suitable for fast charging?

Some people in the industry believe that lithium iron phosphate is not suitable for fast charging. In Wang Shengwei’s view, this problem has two sides. From a material perspective, the intrinsic conductivity of lithium iron phosphate materials is relatively low, only one percent of that of ternary materials. The conductivity of lithium iron phosphate materials must be optimized to meet the needs of fast charging.

Wang Shengwei said that after CATL's transformation, lithium iron phosphate is no longer "the original lithium iron phosphate" and is even better than ternary materials. On the positive electrode, CATL has developed "superconducting electronic network" technology, which enables lithium iron phosphate to have excellent electronic conductivity, up to 1,000 times that of ternary materials.

He pointed out that the current cycle performance of lithium iron phosphate fast-charging batteries is better than that of non-fast charging batteries. In principle, there is no contradiction between cycle performance and charging. So why are traditional batteries not good when used for fast charging cycles? That's because traditional batteries are not designed for fast charging. There will be by-products or side reactions during fast charging. When there are too many side reactions, the cycle will naturally deteriorate. Once the dynamic problem of fast charging is solved, its cycle will at least not get worse. At the same time, fast-charging batteries not only have higher kinetics, but also have a lower energy density than non-fast-charging batteries. It is not surprising that the energy density is lower and there is more electrolyte, so the cycle becomes better. In fact, the lithium iron phosphate fast-charging battery they are currently developing can reach 10,000 cycles.

Ensure fast charging within "healthy charging range"

"After years of research at CATL, we believe that the healthy charging range is related to the irreversible reaction speed of charging. For a fixed chemical system, it will be affected by temperature and voltage. The speed of the irreversible reaction determines the battery's performance during the cycle. The speed at which the capacity decays and the impedance increases, so the focus of our research is how to identify the speed of the irreversible reaction. Fast charging within this "healthy charging range" can achieve fast charging without subjecting the battery to fast charging. To avoid the damage caused by charging, we should take into account both fast charging and long cycle."



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