How does CATL do fast-charging power battery innovation

　　CATL super iron lithium fast charging products have been applied in batches and have accumulated a wealth of application experience. In addition, CATL has also developed a ternary system-based fast charging battery for passenger cars. The fast charging technology will first be used in the electric taxi market.

　　Allowing power batteries to have both high energy density and fast charging characteristics is an important way to relieve consumers' mileage anxiety, and it is also a topic that the industry has been working hard to explore. CATL (hereinafter referred to as "CATL") takes the lead in providing highly innovative solutions with its super R&D capabilities.　　 On March 26, a seminar on the pilot project of high-power charging of electric vehicles was successfully held in Ningde. More than 50 expert representatives from China Electric Power Enterprise Federation, China Automotive Technology Research Center, China Charging Alliance and other industry organizations, well-known domestic and foreign vehicle companies, charging facilities and connector manufacturers participated in the discussion.　　 At the meeting site, CATL showed the participants the charging process of the EnerSpeedy Super Lithium Lithium battery using the "Super Lithium Iron + High Energy Density Fast Charging Graphite" system. The product is a 60Ah super lithium iron battery that can be charged at 5C. The demonstration process took 7 minutes and 12 seconds to complete 20% to 80% charging, and 20% to 100% charging took only 13 minutes and 8 seconds.　　CATL breaks through the conventional and breaks through the technical bottleneck of lithium iron phosphate-graphite system that cannot be quickly charged. On the basis of maintaining the advantages of lithium iron phosphate with high energy density, high safety, and long life, it realizes rapid charging at a rate of 5C. The comprehensive performance of CATLEnerSpeedy super lithium iron battery has been highly recognized by participating experts. In terms of energy density, the energy density of the CATL super lithium iron battery system also has advantages. Among them, 5C high-energy products are above 70Wh/kg, 3C high-energy products are above 115Wh/kg, and the common fast-charge battery system energy in the market The density is only between 40-60Wh/kg. High energy density means that equipped with battery packs of the same weight can greatly increase the range of electric vehicles and reduce the number of recharges.　　In terms of cycle life, taking into account the harsh application conditions of buses, the average number of full charge and discharge times per day is about 2 times. After rough calculation, to meet the eight-year operation demand, the battery cycle needs more than 5600 times. The cycle life of the super iron-lithium battery developed by CATL can reach 10,000 cycles, which can not only fully meet the operation requirements of electric vehicles, but also can be used for cascade utilization such as energy storage after the electric vehicles are retired, bringing more economic value to customers.　　In terms of weather resistance, in order to meet the requirements of low-temperature charging in northern winter and high-temperature operating conditions in southern summer, CATL has specially developed a high-efficiency thermal management system to ensure that the battery is in a reasonable temperature range. When the temperature is low, the battery can be quickly heated, and the fast charging mode can be turned on when the temperature reaches the required temperature; when the temperature is high, the system will cool the battery to truly achieve "full climate" fast charging.　　 Because of this, CATL’s fast-charging super lithium iron battery has been highly recognized by the participants. Many vehicle companies expressed that they will actively promote cooperation with CATL in high-power charging products.　　Technically, how does CATL achieve the breakthrough of this innovative fast charging solution?　　 It is well known that during fast charging of batteries with common chemical systems, the negative electrode will produce by-products, which will affect the cycle and stability of the battery cell. Only negative electrode materials that can withstand fast charging and large current can be used to achieve fast charging. Therefore, in the cognition of many people, 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 charging project, explained that the focus of fast charging is on the negative electrode, and for the choice of positive electrode, whether it is ternary or lithium iron phosphate, it will not affect the performance of fast charging. Reliability. Therefore, the core of fast charging technology is to accelerate the movement of lithium ions between the positive and negative electrodes through chemical system and design optimization, and reduce or block the generation of negative electrode by-products. "However, it is reasonable to say that lithium iron phosphate is not suitable for fast charging, because the traditional lithium iron phosphate has relatively poor conductivity, which causes heat during fast charging." Dr. Wang added, so in response to the above two problems, CATL passed In-depth technical research, innovative solutions are given. On the surface of the negative electrode graphite, CATL adopts the "fast ion ring" technology to modify, the modified graphite takes into account the characteristics of super fast charging and high energy density, and no by-products appear in the negative electrode during fast charging, so the lithium ion in the graphite layer is greatly improved. Embedding speed to achieve excellent rate performance, high energy density and long cycle life.　　 In addition, the fast charging products developed by CATL are equipped with a self-developed thermal management system, which accurately sets the "healthy charging interval" under different temperatures and SOCs, which greatly expands the operating temperature of lithium batteries, thereby realizing "all climate" fast charging. CATL super fast charging products have been applied in batches and accumulated rich application experience. At present, there are more than 2,600 electric buses equipped with CATL super fast charging products in operation on the market. They are operating in good condition and have been used by vehicle companies and bus users. Praise. In addition, CATL has also developed a ternary system-based fast charging battery for passenger cars, which can charge SOC from 5% to 85% within 15 minutes, with an energy density of 190Wh/kg, and a cycle life of more than 2500 times. One step is to ensure 4C fast charging, and the energy density can continue to increase to 210Wh/kg. The fast charging technology will first be used in the electric taxi market to achieve 350KM battery life and complete charging within 30 minutes. At present, many passenger car companies are cooperating with CATL to develop fast charging products.