How CATL Do Fast Charge Battery Innovation

It is an important way to relieve consumers 'mileage anxiety to let the power battery take into account the characteristics of high energy density and fast charging, and it is also a topic that the industry has been exploring. The Ningde era (hereinafter referred to as "CATL") took the lead in giving innovative solutions with its superior R&D capabilities.

On March 26, a pilot seminar on high-power charging of electric vehicles was successfully held in Ningde. More than 50 experts from China Electric Power Enterprise Federation, China Automotive Technology Research Center, China Charging Alliance and many other industry organizations, domestic and foreign well-known vehicle companies, charging facilities and connector manufacturers participated in the meeting.

At the meeting, CATL showed the participants the charging process of the EnerSpeedy Super Iron Lithium battery using the "Super Iron Lithium + High Energy Density Fast Charged Graphite" system. The product is a 60Ah Super iron-lithium battery that can be charged with 5C. The demonstration process takes 7 minutes and 12 seconds to complete 20 % to 80 % of the charge, while 20 % to 100 % of the charge takes only 13 minutes and 8 seconds.

CATL broke the convention and broke through the technical bottleneck that the lithium iron phosphate-graphite system could not charge quickly. On the basis of maintaining the advantages of high energy density, high security, and long life of lithium iron phosphate, CATL achieved a fast charging rate of 5C. The comprehensive performance of CATLENEERSpeedy Super iron lithium batteries has been highly recognized by experts attending the conference.

In terms of energy density, the energy density of the CATL Super Iron Lithium battery system also has advantages. Among them, the 5C fast energy product is above 70Wh / kg, and the 3C high energy product is above 115 Wh / kg. The common fast charging battery system on the market has an energy density of only 40-60 Wh / kg. A high energy density means that a battery pack of the same weight can greatly increase the range of electric vehicles and reduce the number of charges.

In terms of cycle life, considering that the bus application conditions are relatively harsh, the average daily full of about 2 times, rough calculation, to meet the eight-year operating requirements, the battery cycle needs more than 5,600 times. The Super iron lithium core cycle life developed by CATL can reach 10,000 cycles, which can not only fully meet the operating needs of electric vehicles, but also can be used for energy storage and other echelon utilization after decommissioning, bringing more economic value to customers.

In terms of weathering, in order to meet the requirements of low temperature charging in the northern winter and high temperature operating conditions in the southern summer, CATL has developed an efficient heat management system to ensure that the battery is in a reasonable temperature range. At low temperatures, the core can be heated quickly, and the fast charging mode can be turned on when the temperature reaches the requirements; At high temperatures, the system will cool the core and truly achieve a "full climate" of rapid charging.

Because of this, CATL's fast-charging Super iron lithium battery has been highly recognized by the participants. Many vehicle companies have stated that they will actively promote cooperation with CATL in high-power charging products.

Technically, how does CATL achieve this breakthrough in an innovative, fast-charging solution?

It is well known that when the battery of an ordinary chemical system is filled quickly, the negative electrode will produce by-products, which will affect the circulation and stability of the core. It can only be achieved by using a negative electrode material that can withstand high and high current. Therefore, in many people's understanding, the "lithium iron phosphate + graphite" system does not seem to be suitable for fast charging batteries.

In this regard, Dr. Wang, head of the CATL Fast Charge Project, explained that the focus of the fast charge is on the negative pole, and the choice of the positive pole, whether it is the choice of three yuan or the choice of lithium iron phosphate, will not affect the performance of the fast charge, as well as its reliability. Therefore, the core of fast charging technology lies in accelerating the speed of lithium ions moving between positive and negative poles through chemical system and design optimization, and reducing or blocking the production of negative byproducts.

"However, it is said that lithium iron phosphate is not suitable for fast charging, and there is a certain reason because the traditional lithium iron phosphate has poor conductivity and causes heat when it is filled quickly. Dr. Wang added that, so with the two problems in mind, CATL has innovatively proposed solutions through in-depth technical research.

On the negative graphite surface, CATL uses the "fast ion ring" technique to modify the modified graphite. The modified graphite takes into account the characteristics of super fast charge and high energy density. When the negative electrode is filled quickly, the by-product no longer appears, so the lithium ion is greatly improved in the graphite layer. Embedding speed, in order to realize the performance of superior and different times, high energy density and long cycle life.

In addition, the fast charging products developed by CATL are equipped with self-developed heat management systems, accurately set the "healthy charging range" under different temperatures and SOC, and greatly broaden the operating temperature of lithium batteries to achieve "full climate" fast charging.

CATL Super iron lithium fast charging products have been applied in bulk and have accumulated a wealth of application experience. At present, more than 2,600 electric buses equipped with CATL super fast charging products are operating on the market and are in good condition. They have been well received by vehicle companies and bus users. praise.

In addition, CATL has also developed a fast recharging battery based on a three-way system for passenger vehicles. In 15 minutes, the SOC is charged from 5 % to 85 %, the energy density is 190 Wh / kg, and the cycle life is more than 2,500 times. The next step is to ensure 4C is quickly charged. The energy density can continue to increase to 210 Wh / kg. The fast charging technology will first be used in the electric taxi market to achieve 350KM endurance and recharge within 30 minutes. At present, a number of passenger car companies are developing cooperation with CATL for rapid product development.

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