Energy storage is considered to be the most suitable application area for lithium titanate batteries. Lithium titanate batteries can be used in household energy storage, industrial energy storage, military energy storage, industrial energy storage and other fields. Taking Yinlong New Energy as an example, its business ranges from energy storage battery materials, energy storage batteries, energy storage battery BMS to energy storage battery packs and various specific applications of energy storage, and has formed a complete energy storage ecosystem.
When used as a power battery, in view of the characteristics of high safety, fast charging, and long life, lithium titanate batteries are widely used in new energy buses. The performance of lithium titanate batteries has been recognized by customers. Limited by energy density, lithium titanate batteries have not yet been promoted in pure electric passenger cars. At present, there are not many companies that can mass produce lithium titanate batteries. Toshiba of Japan and Austrian Titanium of the United States are the representatives in the world, and Huzhou Weihong and Zhuhai Yinlong are the representatives in China.
1) Toshiba, Japan
The SCiB (Super Charge ion Battery) super lithium battery developed by Japan Toshiba, that is, high-power lithium titanate lithium ion power battery, has a capacity that decays less than 10% after 3000 cycles of charge and discharge under fast charge and discharge conditions. Fast charging with a certain high current can fill more than 90% of the capacity within 5 minutes. And has excellent low-temperature discharge performance, so that the battery can still release more than 80% of the capacity at -30°C.
SCiB batteries have the advantages of fast charging and long life, and are mainly used for energy storage, electric motorcycles, electric vehicles and car start-stop batteries. Toshiba’s SCiB lithium-ion battery has six major characteristics.
(1) The safety is high, and the heat generation is small when the internal short circuit occurs.
(2) Good low temperature performance and can be used at -30℃.
(3) The fast charging ability is strong, and it can be charged as fast as 6min, which is equivalent to the charging rate of 10C.
(4) Long life, cycle life exceeds tens of thousands of times.
(5) High power output, strong instantaneous large current output capability, and power density comparable to capacitors.
(6) The effective SOC window is wide, and the voltage curve of LTO is very flat, occupying more than 85% of the entire SOC range.
Toshiba’s SCiB single cells include power batteries 2.9A·h, 10A·h and energy batteries 20A·h, 23A·h, as shown in Figure 1. Among them, the cycle life of a 2.9A·h battery at 35°C and an SOC range of 20% to 80%, 10C charge/10C discharge cycle life is as high as more than 40,000 times, as shown in Figure 2; the capacity retention rate of the 10A·h battery under the conditions of 5C charge/5C discharge after 20,000 cycles is still above 90%, as shown in Figure 3; the cycle life of a 20A·h battery at 3C charge and discharge current can be maintained at more than 15,000 times, and the capacity retention rate is >80%, as shown in Figure 4.
The voltage of the lithium-ion battery using lithium titanate is only about 2.4V, which is nearly 1.3V lower than the 3.7V of the lithium-ion battery using ternary materials. However, the power characteristics of SCiB are excellent. The power density output capacity of its power battery is close to 4909WL, even reaching 6664WL; the power density input capacity reaches about 5500W/L. However, the energy characteristics of SCiB batteries are relatively poor. Both power and energy batteries are far lower than the energy characteristics of lithium-ion batteries using ternary materials. Another Japanese company, Murata, has developed a new type of lithium titanate battery that uses 5V lithium nickel manganate as the positive electrode. The voltage difference is 3.2V, and the energy density can reach 130w·h/kg, exceeding the current level of lithium iron phosphate batteries.