LR6 battery.Detailed explanation of the development status and advantages and disadvantages of lithium titanate battery technology

　　Detailed explanation of the development status, advantages and disadvantages of lithium titanate battery technology. The development of energy storage technology is one of the key core technologies to promote new energy power generation and improve the security and stability of the power grid. Lithium titanate battery is one of the most promising energy storage batteries. Lithium titanate battery has the characteristics of long cycle life and good safety performance, which is a good fit for the application scenario of grid energy storage.

　　Development status of lithium titanate battery technology

　　Lithium titanate batteries have three-dimensional lithium ion diffusion channels unique to the spinel structure, and have the advantages of excellent power characteristics and good high and low temperature performance. Compared with the carbon negative electrode material, the potential of lithium titanate is high, which results in the solid-liquid layer (SEI) that usually grows on the surface of the electrolyte and carbon negative electrode being basically not formed on the surface of lithium titanate. What's more important is that lithium dendrites are difficult to generate on the surface of lithium titanate within the voltage range used by normal batteries. This largely eliminates the possibility of short circuits inside the battery caused by lithium dendrites.

　　Therefore, the safety of lithium-ion batteries with lithium titanate as the negative electrode is the highest among the various types of lithium batteries I have seen so far. In the past 10 years, research on lithium titanate battery technology at home and abroad has been surging. Its industrial chain can be divided into lithium titanate material preparation, lithium titanate battery production and integration of lithium titanate battery systems and its application in the electric vehicle and energy storage markets.

　　There are not many manufacturers in the world that can mass-produce lithium titanate batteries, mainly represented by the American Altitan Nanotechnology Company and Japan's Toshiba Group. The application markets of lithium titanate batteries mainly include electric vehicles (buses, rail transit, etc.), energy storage markets (frequency regulation, grid quality, wind farms, etc.) and industrial applications. The new lithium-ion battery using lithium titanate as the negative electrode breaks through the inherent limitations of graphite as the negative electrode, and its performance is significantly better than that of traditional lithium-ion batteries, making it one of the most promising energy storage batteries.

　　The main problem faced by lithium titanate batteries in large-scale applications is cost. At the beginning of project development, its price was 4-6 times that of lithium iron phosphate batteries. Although the performance is significantly better than existing lithium-ion batteries, economic factors have greatly limited the market promotion of lithium titanate batteries. Therefore, in order to realize large-scale energy storage applications of lithium titanate batteries, it is necessary to carry out technical reconstruction on the basis of existing lithium titanate batteries for electric vehicles, including technical reconstruction of material systems, battery design, production processes, etc. While ensuring the long-life intrinsic characteristics of lithium titanate batteries, the cost is significantly reduced.

　　Four major advantages of lithium titanate batteries

　　1. Good safety and stability

　　Due to the high lithium insertion potential of the lithium titanate anode material, the generation and precipitation of metallic lithium is avoided during the charging process. Moreover, because its equilibrium potential is higher than the reduction potential of most electrolyte solvents, it does not react with the electrolyte and does not form solids. —The liquid interface passivation film avoids the occurrence of many side reactions, thus greatly improving safety. "Energy storage power stations are the same as electric vehicles, safety and stability are the most important indicators." Yang Kai said.

　　2. Excellent fast charging performance

　　Long charging times have always been an insurmountable obstacle in the development of electric vehicles. Generally, pure electric buses that use slow charging take at least 4 hours to charge, and the charging time for many pure electric passenger cars is as long as 8 hours. Lithium titanate batteries can be fully charged in about ten minutes, which is a qualitative leap compared to traditional batteries.

　　3. Long cycle life

　　Compared with the graphite material commonly used in traditional lithium-ion batteries, the skeleton structure of lithium titanate material hardly shrinks or expands during the process of charging and discharging lithium. It is called a "zero strain" material and avoids the detachment of general electrode materials. / The problem of electrode structure damage caused by unit cell volume strain when lithium ions are inserted, so it has very excellent cycle performance. According to experimental data, the average cycle life of ordinary lithium iron phosphate batteries is 4,000-6,000 times, while the cycle life of lithium titanate batteries can reach more than 25,000 times.

　　4. Good performance in wide temperature range

　　Generally, electric vehicles will have problems charging and discharging at -10°C. Lithium titanate batteries have good wide temperature resistance and strong durability. They can be charged and discharged normally from -40°C to 70°C, whether in the frozen north. Even in the hot south, the vehicle will not be affected by battery "shock", eliminating users' worries.

　　Disadvantages of lithium titanate batteries

　　1. High potential for lithium, resulting in low operating voltage and reduced energy density

　　2. The battery manufacturing process is prone to gas production

　　3. Poor electronic conductivity

　　Why haven’t lithium titanate batteries become mainstream batteries?

　　Lithium titanate material is used as the negative electrode material in batteries. Due to its own characteristics, the material and the electrolyte are prone to interact and produce gas evolution during the charge and discharge cycle reaction. Therefore, ordinary lithium titanate batteries are prone to The flatulence causes the battery cells to bulge and the electrical performance will also drop significantly, which greatly reduces the theoretical cycle life of lithium titanate batteries. Test data shows that ordinary lithium titanate batteries will bloat after about 1,500-2,000 cycles, causing them to be unable to be used normally. This is also an important reason that restricts the large-scale application of lithium titanate batteries.

　　The energy density of lithium titanate batteries is low. In order to store the same energy, the volume must increase, and the corresponding diaphragms, copper foils, aluminum foils, and electrolytes also increase. In addition, titanium itself is a precious metal, which can easily break through the cost control bottleneck. The manufacturing cost is too high. high.

　　The energy storage technology of lithium titanate batteries has been piloted in Japan for a long time. The price difference of Japan's tiered electricity price is as high as 1.6 yuan per kilowatt hour, which is only 70 or 80 cents in China. Compared with the cost, it is not cost-effective at all, so it is difficult to promote.

　　The above is an introduction to the development status and advantages and disadvantages of lithium titanate batteries. The energy density of lithium titanate batteries is relatively low and will not be too mainstream in the future.

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