Detailed explanation of the advantages and disadvantages of lithium titanate battery

The lithium titanate battery is a lithium ion secondary battery which is used as a negative electrode material for a lithium ion battery, lithium titanate, and can be composed of a positive electrode material such as lithium manganate, a ternary material or lithium iron phosphate to form a 2.4V or 1.9V. In addition, it can also be used as a positive electrode, and a 1.5V lithium secondary battery is composed of a lithium metal or a lithium alloy negative electrode.

Why lithium titanate battery has not become mainstream-lithium titanate battery advantages and disadvantages explain

Lithium titanate (LTO) material is used as a negative electrode material in batteries. Due to its own characteristics, the material and the electrolyte are likely to interact with each other and produce gas evolution during the charge and discharge cycle reaction. Therefore, ordinary lithium titanate the battery is prone to flatulence, resulting in a battery pack, and the electrical performance is also greatly reduced, greatly reducing the theoretical cycle life of the lithium titanate battery. The test data shows that the ordinary lithium titanate battery will explode after 1500-2000 cycles, which may cause normal use, which is an important reason for restricting the large-scale application of lithium titanate batteries.

Lithium titanate (LTO) battery performance improvement is a combination of improved performance of individual materials and organic integration of key materials. In response to the requirements of fast charging and long service life, in addition to the anode material, other key raw materials for lithium-ion batteries (including cathode materials, separators, and electrolytes), combined with special engineering process experience, have finally formed The non-flatulence lithium titanate LpTO battery product, and first realized the batch application on the electric bus.

The test data shows that under the conditions of 6C charging, 6C discharge and 100% DOD, the lithium titanate LpTO single cell has a cycle life of more than 25,000 times, and the remaining capacity exceeds 80%. At the same time, the flatulence generated by the battery is not obvious and does not affect. Its lifespan; and the practical application of Chongqing fast-charging pure electric bus also shows that after the battery is grouped, the performance of electric performance is also very good, which can guarantee the daily commercial operation of pure electric bus.

Lithium titanate battery advantages

Why lithium titanate battery has not become mainstream- lithium titanate battery advantages and disadvantages explain

1, good security and stability

When the conventional carbon electrode is overcharged after lithium insertion, the surface of the electrode is liable to precipitate metallic lithium, and the reaction with the electrolyte reacts to generate a combustible gas, posing a safety hazard. The potential of lithium titanate is higher than that of pure metal lithium, it is not easy to generate lithium crystal branches, the discharge voltage is stable, and thus, the safety performance of the lithium battery is improved. A third party organization conducted tests on lithium titanate batteries and found that they were far safer than other lithium batteries because they did not emit smoke, catch fire or explode under harsh tests such as acupuncture, extrusion and short circuit. Therefore, many people in the industry believe that lithium titanate is very suitable for use in military fields where battery stability is extremely high.

The safety and stability of electric vehicles is the most important indicator for consumers. No matter how long the cruising range is, if the safety problem cannot be solved, the consumer will only drive a car with an untimely bomb, and the ultra-safety performance of the lithium titanate battery. The ultra-safe performance of lithium titanate batteries will undoubtedly be favored by consumers.

2, fast charge performance is excellent

Compared with the carbon anode material, lithium titanate has a high lithium ion diffusion coefficient and can be charged and discharged at a high rate. While greatly reducing the charging time, the impact on cycle life is small and the thermal stability is also strong. According to tests, the lithium titanate battery developed by the latest technology can be filled in about ten minutes, which is a qualitative leap than the traditional battery.

Too long charging time has always been an obstacle that is difficult to overcome in the development of electric vehicles. Generally, a slow-charged pure electric bus is used, and the charging time is at least 4 hours. The charging time of many pure electric passenger cars is as long as 8 hours. The rapid charging of electric vehicles is a trend in the future, and consumers are not willing to waste too much time waiting for charging.

3, long cycle life

The battery cycle life determines the cost performance of the entire new energy vehicle, and is the main competitive point after the new energy vehicle is out of the subsidy policy. The extended cycle life of car batteries allows consumers to afford and afford them.

Other traditional lithium-ion batteries, such as lithium iron phosphate batteries, have a problem of greatly reduced capacity and shortened life during use, which not only affects the normal use of the user, but also increases the cost of battery replacement. This poor experience is likely to discourage consumers from electric vehicles, which is not conducive to the sustainable development of the new energy vehicle industry. Lithium titanate batteries solve these problems well.

When lithium titanate battery is charged and discharged, lithium ion intercalation and deintercalation do not cause a change in the crystal structure of lithium titanate, and thus have little effect on the structure of the lithium titanate material. For this reason, lithium titanate is also known as "zero strain material." Lithium titanate battery is superior to the current lithium iron phosphate battery with “slow charge for up to 5 years and fast charge for up to 2 years”. According to the test data, the average battery cycle life is 3,000 times, and the lithium titanate battery can be fully charged and discharged up to 30,000 times. After 10 years as a power battery, it may be used as an energy storage battery. 20 years. This also means that the lithium titanate battery can achieve the same life cycle as the vehicle, and the user does not need to replace the battery in actual use, and almost does not increase the later cost.

4, good resistance to wide temperature

The spinel structure of the lithium titanate battery has a three-dimensional lithium ion diffusion channel, so the lithium titanate battery is also excellent in high and low temperature performance. Generally, electric vehicles will have problems when charging and discharging at minus 10 ° C. The lithium titanate battery has good resistance to wide temperature and good durability, and can be normally charged and discharged at minus 50 ° C to zero at 60 ° C, whether it is in ice or not. Northland, still in the hot south, vehicles will not affect the work due to battery "shock", eliminating the worries of users.

These advantages of lithium titanate battery can greatly save the construction of the charging station site and staffing costs, etc. It is more suitable for the promotion and application in the bus field, and the bus system is the "main battlefield" for the promotion and application of new energy buses in China. Feedback from the bus market, which currently has the highest proportion of new energy vehicles, shows that the fast charging method is more suitable for the actual needs of the current bus market. It has been more than two years since the operation of a new energy bus using a lithium titanate battery in a bus company in Hebei Province. The experience of the relevant person in charge is: “A car can be fully charged in 6-10 minutes, and the driver can change the shift. The gap can be filled."

The lithium titanate battery anode uses lithium titanate, and the market share is very small compared to the mainstream lithium battery for graphite for negative electrodes. According to the data, in the new energy bus, the market share of lithium titanate battery is about 3%, far lower than the market share of 88% of lithium iron phosphate battery; in the field of passenger cars, lithium titanate battery and other The minority technology shares 3% of the market space.

Why lithium titanate battery has not become mainstream-lithium titanate battery advantages and disadvantages explain

Why is lithium titanate battery not the mainstream? There are several main reasons for this phenomenon:

1, lithium battery life, performance, etc. are affected by many aspects, especially the impact of the four major materials. Lithium titanate is only a negative electrode material, and how a material can be improved is also difficult to give the product an unrivalled advantage. Moreover, the positive electrode material is the most important material that affects the performance of lithium batteries.

2. The biggest disadvantage of lithium titanate battery is low energy density and high cost. In particular, the low energy density is determined by the principle performance of the negative electrode material lithium titanate, and it is difficult to have a large breakthrough space. Costs can be reduced by scale, and based on weaknesses in principle. They cannot be changed by technology.

3. As for the lithium titanate battery claimed to have a long service life, it is more difficult to be certified. Battery life is also affected by the positive electrode material, electrolyte, diaphragm, and operating temperature. Lithium titanate is used as a negative electrode, and it also has problems such as flatulence and long-term use consistency. At present, it cannot be proved that lithium acid batteries will last longer than other batteries. At present, lithium iron phosphate and ternary batteries have a cycle life of more than 2,000 times. According to the general use frequency, it can be achieved for 7-10 years. With the advancement of technology, there will be 3,000 times and 4,000 times. Too far away, the situation can be used for more than 10 years or even 20 years of service life, which will exceed the general life cycle of the car. Lithium titanate batteries have no advantage even if they have a long life.

4, lithium titanate battery to do less enterprises will lead to less investment in the industry's overall R & D, from the current battery companies R & D investment and planning investment, few companies will focus on the development of lithium titanate batteries. In the future, other lithium battery technologies will advance faster than lithium titanate batteries.

5, war new production research from the perspective of industry trends, do not believe that international mainstream companies do not do good technology, will shine in China. China's basic research is still far from the level of international advanced enterprises. It is tantamount to whimsical to want to leak in the international technology trend. The market space for lithium titanate batteries will be very limited in the future. There is basically no space in the auto industry, and the space for the auto industry in the future will be smaller than it is now. The field of energy storage can be tried, but it will never become the mainstream. Coupled with the high price, compared with the high cost performance of the future storage of energy batteries, the prospect of lithium titanate in the field of energy storage is also worrying.

Development status

Why lithium titanate battery has not become mainstream-lithium titanate battery advantages and disadvantages explain

Despite the shortcomings of lithium titanate batteries, it has significant advantages in terms of safety performance, charge and discharge, and cycle life, pointing to the pain points of other types of power batteries on the market today. At present, domestic companies engaged in research and development of lithium titanate batteries include Yinlong and Weihong Power. With the increase in research and development of lithium titanate, some technical problems will be broken.

It is understood that Yinlong, which has mastered the core technology of lithium titanate, has developed a fourth-generation high-energy-density lithium titanate battery, which has a 40% reduction in cost and a 60% increase in energy density compared with the third generation. Yinlong also mastered the core technology of hydrogen and titanium research and development, which will effectively solve the problem of battery energy density. At present, Yinlong not only realizes the successful operation of products in more than 30 cities in Beijing, Shijiazhuang, Handan, Zhuhai, etc. Successfully entered the overseas markets of the United States, Germany, France In 2015, Yinlong sold nearly 7,000 vehicles worldwide. It is understood that in the future, Yinlong will also solve the problem of short-lived mileage of new energy vehicles through the combination of lithium titanate battery and fuel cell.

For many years, Micro-Power has been focusing on the research and development of core materials for lithium-ion power batteries, and the development of lithium titanate batteries as its main strategic direction. In 2011, Weihong Power invested in the first fast-charge bus line in China, achieving annual sales of 1.5 billion Yuan by 2015. After years of research, Weihong Power selected a lithium titanate porous composite carbon that can withstand high current and has a spinel structure as a negative electrode material. In 2013, the second generation fast-charge battery LpCO lithium battery was released in order to avoid fast. The high-power current is a threat to battery safety, combined with non-combustion electrolyte, high porosity and high permeability diaphragm technology and STL intelligent thermal fluid technology to improve the safety of charging. On June 9, 2016, at the award ceremony of the “Transformation Innovation Business Award” held by the Financial Times, Weihong Power won the “Low Carbon City Transformation Innovation Achievement Award” and the “Transformation Innovation Business Excellence Award”. It was the only Chinese company selected for the ceremony.

Although the debate on lithium titanate batteries has not stopped, the controversy is not a bad thing. Let the different voices be fully expressed, and the truth can be more and more clarified. Although the controversy over lithium titanate batteries will affect the market and consumers' confidence in lithium titanate batteries to some extent, it may affect investment decisions, but the five advantages of lithium titanate batteries, future lithium titanate Continued breakthroughs in battery technology, as well as the operating experience of companies such as Yinlong and Weihong Power in lithium titanate supporting vehicles, can be judged that lithium titanate batteries in the future will become a "living force" for new energy vehicle battery technology.

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