How to use lithium iron phosphate to produce raw materials

lithium iron phosphate electrode materials are mainly used in various lithium ion batteries. Since the NTT of Japan first revealed the olivine-structured lithium battery cathode material of AyMPO4 (A is an alkali metal, M is a combination of CoFe: LiFeCoPO4) in 1996, Texas State University, John.B.Goodenough and the research group also reported the reversible relocation of LiFePO4 into lithium in 1997.

The United States and Japan unanimously published the olivine structure (LiMPO4), which made the material greatly valued and caused extensive research and rapid development. Compared with the traditional lithium ion secondary battery cathode material, the spinel structures LiMn2O4 and the layered structure LiCoO2, LiMPO4 has a wider source of raw materials, lower cost and no environmental pollution.

The application fields of lithium iron phosphate mainly include:

(1) Energy storage equipment

Energy storage equipment for solar energy and wind power generation systems, UPS for uninterruptible power systems, and solar energy batteries for energy storage equipment (BYD is already producing such batteries);

(2) Power tools

There are high-power power tools (wireless), electric drills and weeders, etc.

(3) Light electric vehicles

Electric locomotives, electric bicycles, recreational vehicles, golf carts, electric pushers, cleaning vehicles, hybrid electric vehicles (HEV), the target of the recent 2-3 years;

(4) Small equipment

Medical equipment: electric wheelchairs, electric scooters), toys (remote control electric aircraft, cars, boats);

(5) Other small appliances

Miner's lamp, implantable medical device (lithium iron phosphate is non-toxic, lithium battery can only meet the requirements of iron and lithium), replacing lead acid, nickel hydrogen, nickel cadmium, lithium cobalt, lithium manganese battery in small appliances.

(6) Mobile power

After a long-term study, German new energy company Deboch successfully developed and mass-produced lithium iron phosphate batteries with composite nano materials, which increased the unit capacity ratio and overcome the problem that the lithium iron phosphate unit volume is too large and is not suitable for digital products. Now a single 32650 (32mm diameter, length 65mm) battery, the capacity exceeds 6000mAh, through two sections, you can reach 12000mAh. The mobile power is up to 38.4Wh, enough to charge the 5.3Wh (1432mAh) iPhone4S nearly 6 times, suitable for long-distance outdoor travel users.

High energy density

Its theoretical specific capacity is 170mAh / g, the actual specific capacity of the product can exceed 140mAh / g (0.2C, 25 ° C);

Safety

It is currently the safest lithium ion battery cathode material; it does not contain any heavy metal elements harmful to human body;

Long life

Under the condition of 100% DOD, it can be charged and discharged more than 2000 times; (Cause: the stability of lithium iron phosphate lattice is good, the insertion and extraction of lithium ions have little effect on the crystal lattice, so it has good reversibility. It is a poor ion conductivity of the electrode, which is not suitable for charging and discharging of a large current, and is hindered in application. Solution: coating the surface of the electrode with a conductive material and doping for electrode modification.

The service life of lithium iron phosphate battery is closely related to its use temperature. The use temperature is too low or too high, which causes great disadvantages in its charging and discharging process and use process. Especially used in electric vehicles in northern China, in the autumn and winter, the lithium iron phosphate battery cannot be powered normally or the power supply is too low, and its working environment temperature needs to be adjusted to maintain its performance. At present, the domestic solution to the constant temperature working environment of lithium iron phosphate battery needs to consider the space limitation problem. The more common solution is to use aerogel felt as the insulation layer.

Charging performance

The lithium battery of lithium iron phosphate cathode material can be charged at a large rate, and the battery can be fully charged in one hour.

Specific physical parameters:

Bulk density: 0.7g/cm³

Tap density: 1.2g/cm³

Median diameter: 2-6um

Specific surface area <30m^2/g

Smear parameters:

LiFePo4: C: PVDF=90:3:7

Pole piece compaction density: 2.1-2.4g/cm3

Electrochemical performance:

Gram capacity>155mAh/g Test conditions: half-cell, 0.2C, voltage 4.0-2.0V

Number of cycles: 2000 times

Domestic and international lithium iron phosphate material manufacturers:

Domestic: Yantai Zhuoneng, Tianjin Bei Te Rui, Tianjin Bamo, Tianjin Strand, Hangzhou Jinma Energy, Yunnan Huilong, Peking University, Hunan Ruixiang Iron Tiger Energy, Taiwan Long Yuan, Taiwan Li Kai, Zhengzhou Langtai, Hangzhou Sainz, Jiangxi Jin Li Technology, Shenzhen Beit Rui.

International: Canada's Phostech, American Valence, American A123, Japanese Sony. Among them, A123 is the largest and has received strong support from the US government and is now bankrupt.

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