Why BYD insists on using lithium iron phosphate batteries

The concept of lithium iron phosphate battery "Lithium iron phosphate battery" refers to a lithium-ion battery using lithium iron phosphate as the positive electrode material. The cathode materials of lithium-ion batteries mainly include lithium cobalt oxide, lithium manganate, lithium nickelate, ternary materials, and lithium iron phosphate. Among them, lithium cobalt oxide is currently the cathode material used in most lithium-ion batteries. 　　Features of lithium iron phosphate battery 　　High-efficiency output: standard discharge is 2～5C, continuous high current discharge can reach 10C, instant pulse discharge (10S) can reach 20C; 　　 Good performance at high temperature: when the external temperature is 65 ℃, the internal temperature is as high as 95 ℃, and the temperature can reach 160 ℃ when the battery is discharged. The battery structure is safe and intact; 　　Even if the battery is damaged internally or externally, the battery does not burn or explode and has the best safety; 　　 Excellent cycle life, after 500 cycles, its discharge capacity is still greater than 95%; 　　 Over-discharge to zero volts without damage; 　　 can charge quickly;  low cost; 　　 No memory effect: When a rechargeable battery is always fully charged, its capacity will quickly fall below the rated capacity. This phenomenon is called the memory effect. Ni-MH and Ni-Cd batteries have memory properties, but lithium iron phosphate batteries do not have this phenomenon. No matter what state the battery is in, it can be charged and used at any time without having to discharge it before charging; 　　Small size and lightweight, the volume of the lithium iron phosphate battery of the same specification and capacity is 1/3 of the volume of the lead-acid battery, and the weight is 1/3 of the lead-acid battery; 　　 No pollution to the environment, the battery does not contain any heavy metals and rare metals (the nickel-hydrogen battery requires rare metals), non-toxic (SGS certification), non-polluting, in line with European ROHS regulations, is an absolutely green battery. However, there is a large amount of lead in lead-acid batteries, and if they are not handled properly after being discarded, they will still cause secondary pollution to the environment, while lithium iron phosphate materials are pollution-free in both production and use processes. 　　How about a universal lithium iron phosphate battery? Why BYD insists on using lithium iron phosphate batteries 　　How about a universal lithium iron phosphate battery 　　A123, a subsidiary of Wanxiang Group, is an American company dedicated to the professional development and production of lithium-ion batteries and energy storage systems. Let's take the Wanxiang A123 power lithium battery as an example to take a look at the performance of the Wanxiang lithium iron phosphate battery. 　　A123 mainly provides lithium iron phosphate cathode materials, and at the same time, it focuses on the power lithium battery market and takes lithium batteries for vehicles as a key development direction. A123 lithium-ion products simultaneously solve the three problems that affect power lithium batteries in terms of high power, safety, and long life. 　　A123 lithium iron phosphate battery performance: 　　 Power: High-energy products have a capacity density of 140W·h/kg, an output density of 3000W/kg, and can withstand high-power pulse discharge rates up to 100C (100 times the nominal capacity current discharge); 　　The capacity density of high-power products is 140W·h/kg, and the output density is 3000W/kg; 　　 Medium power products have higher performance and efficiency advantages; 　　Safety: It has been verified by multiple national laboratories and multiple automotive customers, with superior tolerance for abuse. 　　 Cycle life: A123’s Nanophosphate technology provides excellent performance and cycle life. In the low-interest rate cycle, it can provide thousands of cycles, even under the 10C discharge rate cycle, it also provides more than 1,000 complete cycles. 　　How about a universal lithium iron phosphate battery? Why BYD insists on using lithium iron phosphate batteries 　　 Why BYD insists on using lithium iron phosphate batteries The lithium iron phosphate battery is a domestic lithium battery completely independently researched and developed by BYD. It has invested a lot of money. It is now a mature product and has been widely used in China; although compared with foreign lithium battery products, the characteristics of lithium iron phosphate batteries are not perfect. , But because of its existence, it broke the foreign technology monopoly and created a way for us to take our own lithium battery research and development route, so I admire its spirit very much. In addition, BYD insists that the use of lithium iron phosphate batteries will not explode. In addition, let's first find out the key factors and support for the development of China's new energy vehicles. In view of the reality of our industry, let's compare the status quo and development direction of ternary and lithium iron phosphate. 　　Comparing the advantages and disadvantages of ternary and lithium iron phosphate batteries: 　　 1. If we continue to develop the ternary, our power lithium battery will always be in a state of catching up. Not only will it not be able to overtake in corners, but it will also lose the safety of new energy vehicles. 　　 Currently, the core technologies of modified lithium manganate and ternary lithium are in the hands of Japanese and Korean companies. Especially for ternary lithium, whether it is technology, process or equipment, the Japanese and Korean industry leaders have reached a very mature and stable stage. If the development direction of China's new energy vehicle power battery is positioned to develop ternary lithium batteries, it will not only catch up with Japanese and Korean companies for a long time but also has fallen into a development bottleneck due to the lack of key technologies, processes, and equipment. Technology is severely constrained by Japanese and Korean companies, and the scale is far less than that of Japanese and Korean corporate giants. Samsung SDI reduced the sales price of 18650-2.2AH batteries to US$1 per unit at one time this year, almost driving its domestic counterparts into desperation. In the case that the performance and price of domestic ternary power batteries cannot be compared with Japanese and Korean giants, if we adhere to the ternary route on new energy vehicle power batteries, I am afraid that we are still catching up, and we have been killed by international giants. , Let alone overtaking in a curve. The end result will be the same as the development of traditional cars. High-end cars and core technologies still originate from international giants. Even if we give up the market, we will not be able to exchange for core technologies. 　　 lithium iron phosphate battery is different. Japanese and South Korean companies have basically not set foot, and the main international competitors are from the United States. Although one of the two basic patents is in the United States (A123 and Valence are the main representatives of lithium iron phosphate batteries in the United States), the technical level of China and the United States is not much different, and China is the world’s largest investment in the field of lithium iron phosphate and the largest production and sales volume. s country. 　　 With the acquisition of A123 by Wanxiang Group, Chinese companies have in fact mastered the world's most advanced technology and technology for lithium iron phosphate batteries. The absolute advantages of lithium iron phosphate batteries over ternary lithium batteries in terms of safety and cycle life are exactly the key elements and development needs of China's new energy vehicles. As long as its development status is clarified, and investment is increased to solidify this advantage, China's new energy vehicles are completely possible to overtake on corners. 　　2. The choice of ternary, the lack of forward-looking top-level design, the shortage of global nickel and cobalt resources, their large-scale application will cause market prices to skyrocket, especially the reserves of these two elements in China cannot be supported. 　　The material formula of the ternary lithium battery, whether it is lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminate, is inseparable from two precious metals, namely cobalt and nickel. Both metals are scarce in China and limited in global reserves. Among them, more than 90% of the cobalt used in China needs to be imported. Nickel is mainly used in the production of stainless steel. Both precious metals have international futures transactions. The prices are not only high but also volatile. 　　If China decides to use ternary lithium battery as the main power battery development route, according to the government's plan, by 2020, the production capacity of new energy vehicles will reach 2 million, and the number of new energy vehicles will reach 5 million. Calculated on the basis of an average charge of 80KWH of the power battery of each new energy vehicle, 5 million new energy vehicles require 400 billion WH batteries, which does not include batteries for replacement and backup. Once this kind of demand is pushed to the market, it will quickly drive the price of cobalt and nickel futures to skyrocket, which will drive its spot market prices to skyrocket, and the future price trend of ternary lithium batteries will rise sharply. A big reason why the promotion of new energy vehicles in China has not reached the expected goals of the policy is that the prices remain high. Among them, the most important reason is that the price of power lithium batteries, which account for nearly 50% of the cost of new energy vehicles, remains high. The result of the ternary route is that the price of new energy vehicles is higher, and government subsidies are also required to be more, and market promotion will never be achieved. 　　 Lithium iron phosphate batteries are just the opposite. They do not contain any precious metals, and iron oxide and lithium carbonate, the main raw materials for the production of cathode materials, are abundant in China. If the downstream new energy vehicle market demand is enlarged, the cost of its upstream materials will plummet under the drive of the scale effect. The decline in the price of cathode materials, which accounts for more than 30% of the cost of lithium iron phosphate batteries, will prompt a rapid decline in the price of lithium iron phosphate batteries. . 　　3. In terms of vehicle safety design, China's new energy vehicles use ternary lithium batteries as power batteries, which may pose huge safety risks. 　　 Tesla caught fire three times, one of which was caused by a metal sheet piercing the battery. However, due to the complete safety design of the Tesla vehicle, the three fires did not cause casualties. The deoxidation temperature of the ternary material is 200°C, and the exothermic energy exceeds 800J/g. The ternary lithium battery cannot pass the acupuncture experiment, indicating that the ternary battery can easily cause a safety accident in the case of an internal short circuit. 　　 At present, China's new energy vehicle safety design cannot reach Tesla's level in the short term. The use of ternary lithium battery as a new energy vehicle power battery poses a huge safety hazard. It is about the safety of passengers' lives. Even if the probability of occurrence of such a safety hazard is one in 100,000, it is unacceptable. The stability of lithium iron phosphate battery at a high temperature can reach above 390℃, which guarantees the inherent high safety of the battery. It will not explode or burn due to overcharge, high temperature, short circuit, impact, and it can easily pass through needles. experiment. This safety feature is most suitable for China's new energy automobile industry, which is still in its infancy. 　　 4. Judging from the consumption characteristics and habits of China's new energy vehicles, ternary lithium batteries are not suitable for China's new energy vehicle power batteries. 　　 Tesla is called "the toy of the rich". The battery capacity is designed to have a cruising range of 400KM, but most of the time, the actual operation is only about 200KM, which is shallow charge and shallow discharge, so the cycle life is guaranteed. However, most of China's new energy vehicles are used in public transportation, government service, special purpose vehicles, and residential passenger vehicles. The characteristics of their use are that most of them have fixed lines and frequency requirements every day. They are deep charge and deep discharge, and the ternary lithium battery is above 95% DOD. The capacity decays quickly, and the cycle life is less than half of that of lithium iron phosphate batteries. The average use of new energy vehicles is more than 8 years. If the power lithium battery maintains a capacity of more than 80% under the condition of deep charging and deep discharge, the service life of the ternary lithium battery will be less than three years, while the lithium iron phosphate battery can basically meet 8 years Requirements for use. 　　Under the current state's relevant subsidy policy, there are corresponding government subsidies for the first purchase of new energy vehicles, but there is no subsidy for the second purchase of batteries. The ternary lithium battery needs to be replaced twice during the life cycle of a new energy vehicle, which will greatly increase the economic burden of users and will not be accepted by end-users. If the ternary lithium battery is to have the same service life as lithium iron phosphate, it can only be shallowly charged and discharged, and the battery capacity needs to be increased by at least 50%. In this way, the advantage of higher energy density will be lost, the volume will be larger than the lithium iron phosphate battery of the same performance, the weight of the battery will be heavier, and the price will be much higher than that of the lithium iron phosphate battery. 　　The lithium iron phosphate battery will be most suitable for the development of electric vehicles in the future: 　　 It is foreseeable that the development of pure-electric passenger vehicles and special vehicles in the future will have the following characteristics: First, three types of vehicles will be formed, namely under 1.3 tons, 1.3 to 1.7 tons, and over 1.7 tons. Corresponding to each kilowatt-hour of electricity, the cruising range is 10KM, 8KM, and 6KM respectively, and the corresponding assembled battery weight is also about 300KG, 500KG, and 800KG respectively. The second is that all batteries are equipped with DC fast charging and AC slow charging. Third, both the body and the chassis will use new materials and take the route of lightweight composite materials, such as aluminum alloy and carbon fiber composite materials. 　　 Therefore, in the development of China's future electric vehicles, it is no longer a major problem that the power battery requires a higher energy density and a lower energy density because the vehicle needs to maintain a certain weight in terms of safety and center of gravity stability. The body and chassis are lighter, and the battery is heavier. It will be a brand new automotive system design--- a lightweight design of the body and chassis, and a supporting the design of the lithium iron phosphate battery pack to ensure the stability of the body weight and the center of gravity of the body. 　　The key to the large-scale popularization of new energy vehicles is safety in use, stable and reliable performance, and low cost. Only in this way can they be accepted by the market and liked by the public. 　　 Lithium iron phosphate battery can guarantee a combined energy density of 100~120WH/KG, coupled with its best safety and predictable economy, it will definitely be the best choice for China's new energy vehicle power battery development. 　　 We only have no doubts, no slack, and no toss. I believe that after 20 years, China’s new energy vehicles are already popular, and the heart must be lithium iron phosphate power batteries. 　　How about a universal lithium iron phosphate battery? Why BYD insists on using lithium iron phosphate batteries 　　 Application field of lithium iron phosphate battery 　　 Lithium iron phosphate power battery has the above-mentioned characteristics and produces a variety of batteries with different capacities, which will soon be widely used. Its main application areas are: 　　Large electric vehicles: buses, electric vehicles, tourist attractions, and hybrid vehicles, etc.; 　　Light electric vehicles: electric bicycles, golf carts, small flat battery carts, forklifts, cleaning vehicles, electric wheelchairs, etc.; 　　 Power tools: electric drills, electric saws, lawnmowers, etc.; 　　Remote control cars, boats, airplanes, and other toys; 　　 Energy storage equipment for solar and wind power generation; 　　UPS and emergency lights, warning lights, and miner's lamps (the best safety); 　　 Replace the 3V disposable lithium battery and 9V Ni-Cd or Ni-MH rechargeable battery in the camera (the same size); 　　Small medical equipment and portable equipment, etc. 　　 Here is an application example of replacing lead-acid batteries with lithium iron phosphate power batteries. Using a 36V/10Ah (360Wh) lead-acid battery, its weight is 12kg, it can walk about 50km with one charge, the number of charges is about 100 times, and the use time is about 1 year. If the lithium iron phosphate power battery is used, the same 360Wh energy (12 10Ah batteries in series) is used, and its weight is about 4kg. It can walk about 80km per charge, charge up to 1000 times, and have a service life of 3 to 5 years. Although the price of lithium iron phosphate power batteries is much higher than that of lead-acid batteries, the overall economic effect is better to use lithium iron phosphate power batteries, and they are lighter in use.