The safest battery lithium titanate energy storage battery
The future prospects of lithium titanate batteries have obvious advantages and disadvantages. How to learn from each other's strengths and make up for the shortcomings is the key
From a technical perspective, the advantages and disadvantages of lithium titanate materials compared to lithium iron phosphate materials are extremely obvious.
1. Lithium titanate batteries have shortcomings in terms of energy density and cost.
This is also the main reason why lithium titanate batteries are not yet popular. First of all, in terms of energy density, the actual specific energy of the current lithium iron phosphate battery is 100-120Wh/kg, and the ternary battery is 150-200Wh/kg. Among them, the nickel-cobalt-aluminum ternary battery used by TSLA reaches 252Wh/kg. The lithium titanate battery is only 90Wh/kg.
Secondly, in terms of cost, the average price of 0.5C charging and discharging iron-lithium energy storage cells is about 0.85-1 yuan/Wh, ternary energy storage is about 1-1.1 yuan/wh, and the cost of lithium titanate ion battery is about 3 The element battery is more than 2 times, and it is not dominant. But in the view of the "cask effect", as long as there is a 1% problem, an additional 100% effort must be made.
2. Special needs derived from special geographical environment
Due to the vast geographical territory of China, there are huge differences in climate conditions between the north and the south. Kunming in the south is like spring all year round, while the average temperature in Heilongjiang in the north is 3°C throughout the year, and the lowest temperature in winter is as low as minus 41°C. At the temperature of 0~-20°C, the lithium iron phosphate battery has a discharge capacity equivalent to 88.05%, 65.52% and 38.88% of the discharge capacity at a temperature of 25°C, which requires the assistance of a thermal management system.
There is a problem. In the case of maintaining normal working conditions, the lithium iron phosphate energy storage system in the north needs to install a large number of air conditioners, strengthen post-maintenance, and replace batteries. This has led to a sharp increase in the cost of the energy storage system and a significant reduction in the capacity density of the entire unit space.
On the other hand, the spinel structure of lithium titanate battery has three-dimensional lithium ion diffusion channels, so lithium titanate battery has excellent performance in high and low temperature performance. For battery needs in extremely cold and harsh climates.
3. Safety issues are no longer a "stumbling block" in the development of energy storage
The explosion accidents of energy storage keheng-battery.com/Portable-power-station.html target='_blank'>Power Stations over the years are vivid in our minds, and potential safety hazards have undoubtedly restricted the progress of the energy storage industry. Once the traditional carbon electrode is overcharged after lithium intercalation, metal lithium is easily precipitated on the surface of the electrode, and the reaction with the electrolyte will generate flammable gas, which brings safety hazards.
"China's power grid is one of the bottom lines of national security, which cannot be challenged. Its investment in the power grid security system is also cost-free, and it adopts a "zero tolerance" attitude towards any security risks." An executive of a well-known enterprise revealed. In fact, not only the State Grid, but also the corresponding application scenarios include military industry, rail transit, etc., so the battery cost is no longer an indicator of choice.
When lithium titanate is used as the negative electrode material, the lithium intercalation potential is high, and the formation and precipitation of metallic lithium can be avoided during the charging and discharging process, and because the equilibrium potential is higher than the reduction potential of most electrolyte solvents, it does not react with the electrolyte, and does not react with the electrolyte. The formation of a solid-liquid interface passivation film avoids many side reactions, so the safety performance is significantly better than that of traditional lithium-ion batteries. For example, in its laboratory, Bo Leida has carried out extreme tests such as shooting, soaking, acupuncture, and high-temperature baking on lithium titanate batteries, but the lithium titanate batteries did not smoke, catch fire and explode.
4. Life cycle is closely related to energy storage cost reduction
Traditional lithium batteries generally use graphite as the negative electrode material. Graphite is a two-dimensional layered structure. During the process of lithium ion deintercalation, the volume change rate reaches ±10%, which seriously reduces the cycle life of both. The lithium titanate material has a stable structure. During the charging and discharging process, the intercalation and deintercalation of lithium ions will not cause changes in the crystal structure of lithium titanate, which is called a zero-strain material.
According to the experimental data, the cycle life of lithium titanate battery can reach more than 25,000 times, and the life span can reach 30 years. The cycle life of ternary lithium and lithium iron phosphate batteries is about 2,000 to 3,000 times. Therefore, in practical applications, if the life of the energy storage battery is only a few years, the problem of frequent battery replacement will occur, which greatly increases the operating cost. And it is easy to increase the risk of unstable performance, which is not as worry-free as lithium titanate batteries.
5. Excellent charging and discharging performance, matching the power station frequency modulation just needs
The three-dimensional lithium ion channel of lithium titanate can realize rapid deintercalation of lithium ions. Compared with other negative electrode materials, lithium titanate has a high lithium ion diffusion coefficient, fast electrochemical reaction speed, and meets the needs of high-rate rapid charge and discharge, which just hits the "lifeblood" in the field of energy storage auxiliary thermal power frequency modulation.
Frequency modulation requires a "power-type energy storage system", and the characteristics of high-rate charge and discharge of lithium titanate are very suitable for the short-term, frequent and rapid charge and discharge requirements of frequency modulation services. The maximum rate of conventional lithium batteries is only 2C, and lithium titanate can achieve more than 4C. Therefore, it takes about 30 seconds for the full load of the black start belt of diesel generators, and only about 2 seconds through the lithium titanate solution. Under the same output power, with more than three times the cycle life, the frequency modulation mileage theory can reach more than six times that of other lithium-ion batteries.
Due to the cost issues mentioned above, the initial investment creates the illusion that the lithium titanate battery is not cost-effective. However, in the long cycle of frequency regulation power plants, the mileage cost is an important indicator to evaluate the frequency regulation economy of energy storage power plants. From this point of view, the energy storage battery used in frequency modulation must choose a power battery with fast charging and discharging speed and long life. In other words, as long as the initial investment cost of lithium titanate battery energy storage does not exceed 6 times that of other lithium battery energy storage, its cost-effectiveness is theoretically advantageous.
6. Large enterprises are actively deploying and are optimistic about the future prospects
In fact, in addition to Bo Leida, PetroChina and Gree also threw an "olive branch" to lithium titanate battery technology.
Dong Mingzhu, head of lithium titanate battery at Yinglong Energy, said, "The biggest feature of lithium titanate battery is safety. No matter high temperature or low temperature, it will not catch fire or explode. We chose this project not to make money, but because future development needs to be done.”