How to distinguish between lithium titanate battery and lithium iron phosphate battery

Lithium iron phosphate battery refers to a lithium ion battery using lithium iron phosphate as a positive electrode material. Its characteristic is that it does not contain precious elements such as cobalt. The raw material price is low and phosphorus and iron are abundant in the earth's resources, and there is no problem of feeding. Its working voltage is moderate (3.2V), its capacity per unit weight is large (170mAh/g), high discharge power, fast charging and long cycle life, high stability under high temperature and high heat environment.

Lithium iron phosphate battery advantages

Compared with the more common lithium cobalt oxide and lithium manganate batteries currently on the market, lithium iron phosphate batteries have at least five advantages: higher safety, longer service life, and no heavy metals and rare metals (raw materials), low cost, fast charging and wide operating temperature range.

Lithium iron phosphate battery

Lithium iron phosphate has some performance defects, such as low tap density and compaction density, resulting in lower energy density of lithium ion battery; higher material preparation cost and battery manufacturing cost, lower battery yield and poor consistency; poor product consistency; intellectual property issues.

Analysis and Comparison of lithium titanate battery and Lithium Iron Phosphate

In the field of pure electric vehicles, the batteries are mostly lithium iron phosphate or ternary lithium. Recently, the core competitiveness of Gree's passenger car that Gree wants to acquire is a lithium titanate battery with a different approach.

Domestic automobile manufacturers use more ternary lithium batteries and lithium iron phosphate batteries. Lithium titanate has not yet been scaled up. And the price of lithium titanate battery is high (high production cost, high humidity control requirements), about 9 yuan per watt hour, and the difference between the lithium iron phosphate battery and the ternary lithium battery of 2 yuan per watt hour is also very large.

Is lithium titanate battery superior to lithium iron phosphate? This starts with the performance of the two batteries. It is well known that the performance of lithium batteries is mainly determined by the positive electrode, the negative electrode, the electrolyte and the separator. The positive and negative materials have important influences on the key parameters of the battery, such as capacity, energy density, cycle life, safety, rate performance and cost.

Lithium titanate battery breaks the traditional battery technology route with graphene as the negative electrode, and uses lithium titanate as the negative electrode material, which makes it a heterogeneous in the eyes of the peers. But it is the characteristics of lithium titanate itself that makes the battery of this material have remarkable characteristics.

Comparative analysis of lithium titanate battery and lithium iron phosphate

Taking lithium iron phosphate-graphene and ternary-lithium titanate lithium batteries as examples, lithium titanate batteries are inferior in terms of energy density alone. According to the Northeast Securities Research Report, the actual specific energy of lithium iron phosphate battery is 100-120Wh/kg, of which the nickel-cobalt-aluminum ternary battery used by Tesla is 252Wh/kg, while the silver-plated lithium titanate battery is only 90Wh/ Kg, only half of some graphite anode materials.

From the cost point of view, lithium titanate battery has no advantage. At present, the raw materials of Yinlong lithium titanate battery include titanium hydroxide and lithium hydroxide, which are more expensive than graphite anode materials. According to the survey results of China Battery Network, the current cost of lithium iron phosphate and ternary batteries is 1100 -1200 Yuan/KWH, while the cost of lithium titanate batteries is about 2-3 times that of ternary batteries.

The energy density is doubled and the cost is 2-3 times higher. How does the lithium titanate battery participate in the market competition? Obviously, it is its own unique advantage that has touched some people in the industry.

The safety of lithium titanate battery is outstanding

When the lithium titanate is used as the negative electrode material, the potential platform is as high as 1.55V, which is more than 1V higher than the conventional graphite negative electrode material. Although some energy density is lost, it means that the battery is safer. Lu Lu, a technical expert, once said that the battery needs to be low when the battery is rapidly charged. However, if it is too low, the lithium battery will easily precipitate very active metal lithium. This lithium ion is not only conductive but also reacts with the electrolyte. Releases heat, produces flammable gases, and causes a fire. Lithium titanate avoids the precipitation of lithium ions because the high voltage of 1V avoids the negative voltage of 0, thus ensuring the safety of the battery.

Since the lithium titanate battery can be safely used in high temperature and low temperature environments, it also shows its important advantages of wide temperature resistance (especially low temperature resistance). At present, the safe working temperature range of the Yinlong lithium titanate battery is between -50 degrees and 65 degrees, while the ordinary graphite-based negative electrode battery begins to attenuate when the temperature is lower than -20 degrees, and the charging capacity is only -30 degrees. 14% of the total charge capacity does not work properly in cold weather.

Comparative analysis of lithium titanate battery and lithium iron phosphate

In addition, since the lithium titanate battery has a volume change of only 1% even if it is overcharged, it is called a zero strain material, which makes it have an extremely long life. Yincang Wei, chairman of Yinlong, once said that the life of Yinlong lithium titanate battery can reach 30 years, which is equivalent to the service life of the automobile, while the average life of ordinary graphite anode material battery is only 3-4 years. Lithium titanate batteries are less expensive from a life cycle perspective.

The last advantage of lithium titanate is its fast charge and discharge capability and high charge rate. At present, the charging rate of Yinlong lithium titanate battery is 10C or even 20C, while the battery charging magnification of ordinary graphite anode material is only 2C-4C.

Based on these technical characteristics of lithium titanate batteries, the industry believes that it meets the needs of new energy buses and large-scale energy storage equipment. In the case of a bus, the average mileage is not more than 40 kilometers. It takes at least a few minutes for each terminal to wait for the next departure. At this time, the disadvantage of low energy density of the lithium titanate battery does not affect the use of the passenger car, but reflects the benefits of fast battery charging. As a public transport, buses place higher demands on the safety and durability of batteries.

Six new energy buses equipped with lithium titanate batteries entered the Ministry of Industry and Information Technology's “Recommended Models for New Energy Vehicle Promotion and Application” (fourth batch in 2017), which means the official recognition of the maturity of this battery technology. With the late subsidies in place, the price of lithium titanate electric buses will also decline, and it is expected to continue to drive sales in the future. In the face of the huge new energy bus market, lithium titanate enterprises began to expand production.

The page contains the contents of the machine translation.