LiFePO4 battery manufacturing process

LiFePO4 batteries just different from other lithium battery of the anode material, it’s process similar to other lithium.Big process is as follows: ingredients – coated – rolling – cutting – production – winding – assembly – laser welding – baking – filler – activation – into – seal – cleaning – – sorting.The main difference in the LiFePO4 material conductive performance is poor, so do more fine material particles, large surface area, causing ingredients dispersion was difficult, and easy to water absorption.The other difference is really small.
Lithium ion batteries As a kind of high performance second green battery, high voltage, high energy density (including volume energy and mass ratio), the use of low self-discharge rate, wide temperature range, long cycle life, environmental protection, no memory effect, and can the advantages of large current charge and discharge.To improve the performance of lithium ion batteries, to a large extent depends on to improve the performance of electrode materials, especially the anode material.The most widely studied nowadays cathode material LiCoO2, LiNiO2, LiMn2O4, but as a result of cobalt toxic and limited resources, lithium nickel acid preparation is difficult, poor circulation performance and high temperature performance of manganese acid lithium factors, restricting their application and development.Therefore, the development of the new type high-energy cheap is very important for the development of the anode materials for lithium ion batteries.

The structure of the LiFePO4
LiFePO4 (LiFePO4) has olivine structure, for a slightly twisted the six-party close packing, the space group is Pmnb type.
LiFePO4 by FeO6 cathedral and PO4 tetrahedron form space frame, P tetrahedron position, while Fe and Li fill in cathedral gap, the Fe Angle of cathedral position, Li octahedron of edge position.Lattice a FeO6 octahedron with two FeO6 cathedral and join a PO4 tetrahedral edge, while the PO4 tetrahedron with a FeO6 two LiO6 octahedron octahedron and edge.Because almost six party closely arranged, the oxygen atoms of the accumulation of making lithium ion can only be embedded in the two-dimensional plane to take off, and therefore has a relatively high theoretical density (3.6 g/cm3).In this structure, Fe2 + / Fe3 + relatively metallic lithium voltage of 3.4 V, the theory of material specific capacity is 170 ma · h/g.In the material form strong P – O – M covalent bond, greatly stability of the crystal structure of materials, leading to materials with high thermal stability.

The performance of LiFePO4
1) high energy density
Its theoretical specific capacity is 170 mAh/g, actual specific capacity of product can be more than 140 mAh/g (0.2 C, 25 ° C).
2) security
Is the safety of lithium ion battery cathode material;Do not contain any harmful heavy metals;
3) long life
Under the condition of 100% DOD, can charge and discharge more than 2000 times;(reason: LiFePO4 lattice stability is good, the lithium ions embedded and emergence of lattice impact is not big, so it has good reversibility.The deficiencies are ionic conductivity electrode is poor, not suitable for large current charge and discharge, stuck in applications.Solution: the electrodes coated on the surface of conductive material, doped with electrode modification.)

The service life of the LiFePO4 battery with temperature, temperature too low or too high in the charging and discharging process and use process produce greatly bad hidden trouble.Electric cars use especially in northern China, in the fall and winter normal power supply of the LiFePO4 batteries or power supply is too low, need to adjust its working environment temperature to maintain its performance.At present, the domestic solve the LiFePO4 battery temperature working environment should be considered space limitations, the common solution is to use the aerogel blanket as a therm