Lithium ion power cell and preparation method thereof

Abstract

The invention discloses a lithium ion power cell and a preparation method thereof. A cathode piece of the lithium ion power cell comprises: by mass, 84 to 95% of lithium titanate, 2 to 10% of at least one adhesive and 3 to 10% of at least one conductive agent. An anode piece of the lithium ion power cell comprises: by mass, 83 to 95% of lithium iron phosphate, 1 to 10% of at least one adhesive and 3 to 11% of at least one conductive agent. In preparation of the cathode piece or the anode piece of the lithium ion power cell, pollutants of N-methyl-2-pyrrolidone (NMP) and polyvinylidene fluoride (PVDF) are not utilized, and thus preparation processes have the advantages of low energy consumption, environmentally friendly characteristics and low cost. The lithium ion power cell prepared by the preparation method has the advantages of high safety and long service life.

Description

technical field [0001] The invention relates to a lithium ion power battery and a preparation method of the lithium ion power battery. Background technique [0002] The world's energy and environmental protection situation is becoming increasingly tense, and batteries are increasingly favored by people as a new energy source. Due to its high energy density, light volume, small weight, environmental protection and pollution-free, lithium-ion batteries have become the main direction of new energy development. With the rapid development of electric vehicles, space technology, national defense industry, and power storage systems, higher requirements are put forward for the specific capacity, cycle life, and safety of secondary batteries, and the electrochemical performance of batteries is improved. It can start with electrode materials and other aspects. [0003] Traditional lithium-ion batteries all use graphite as the main active material of the negative electrode material. ...

AI Technical Summary

Problems solved by technology

And eventually cause performance degradation and battery attenuation

At the same time, graphite electrodes also have the problem of co-intercalation of the electrolyte, which will also affect the cycle stability of the electrode.

[0004] The positive electrode material is also an important part of lithium-ion power batteries. The first positive electrode material industrialized by Sony mainly uses lithium cobalt oxide (LiCoO 2 ), and now because cobalt resources are becoming more and more scarce, its price is getting higher and higher, and its thermal stability is poor, and it has a greater destructive effect on the environment. Therefore, more and more researchers and engineers will Attention has been turned to other cathode materials, and LiNiO is the cathode material that has attracted much attention for lithium-ion power batteries. 2 , LiMn 2 o 4 , LiFePO4, etc., LiNiO 2 The capacity is large, but it is difficult to prepare, it is difficult to obtain a relatively pure substance, and its safety performance is not good; LiMn 2 o 4 The price is relatively cheap, and the safety performance is good. However, its cycle performance is poor, the capacity is not high, and the high temperature performance is not good. LiFePO 4 Does not contain precious elements, raw materials are cheap, and resources are extremely rich

[0005] When making electrode slurry, the commonly used binder is PVDF, and the commonly used solvent is NMP. However, the problem with using NMP is that it is highly polluting to the environment, and NMP is a flammable and explosive item. In the process of making electrode slurry, It is necessary to pay attention to the removal of NMP in a timely manner. In addition, because NMP can absorb water, which will affect the adhesive performance of the adhesive. Therefore, in the process of making electrodes, the moisture content of NMP must be controlled, so the process will become complicated.

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