Lithium ion battery and preparation method thereof

A lithium-ion battery and battery casing technology, which is applied in the manufacture of electrolyte batteries, secondary batteries, battery electrodes, etc., can solve the problems of shortened battery life, piercing the isolation film, and hidden safety hazards of lithium-ion batteries to improve cycle performance , high magnification effect

Pending Publication Date: 2020-07-10
FARASIS TECH (GANZHOU) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

During this reaction process, if the lithium ion insertion rate of the negative electrode material cannot reach the electron migration rate of the charging current applied by the battery cell, lithium metal will be precipitated on the surface of the negative electrode, the capaci

Method used

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  • Lithium ion battery and preparation method thereof

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preparation example Construction

[0062] A second aspect of the present invention provides a method for preparing negative electrode slurry, the method comprising the following steps:

[0063] (1) dry-mixing the negative electrode active material, negative electrode conductive agent, thickener and dispersant to obtain a mixture;

[0064] (2) Add water to the mixture, then stir at constant temperature to obtain slurry S1 with a solid content of 60-70%;

[0065] (3) Add N-methylpyrrolidone and water to the slurry S1, and then stir at a constant temperature to obtain a slurry S2 with a solid content of 56-58%;

[0066] (4) Add negative electrode binder and water to the slurry S2, and then stir at a constant temperature to obtain a slurry S3 with a solid content of 50-54%, a viscosity of 1400-2000mPa·S, and a fineness of 10-35 μm;

[0067] (5) Sieve the slurry S3 through the first sieve and the second sieve in sequence, and then defoam to obtain the negative electrode slurry.

[0068] Preferably, in step (1), th...

Embodiment 1

[0103] (1) Preparation of positive pole piece

[0104] Dissolve the positive electrode binder polyvinylidene fluoride with N-methylpyrrolidone solvent and configure it into a binder solution with a mass fraction of 6%, and then add the positive electrode active material LiFePO under stirring 4 (The gram capacity is 140mAh / g), the positive electrode conductive agent carbon nanotube conductive agent, and then further stirred to form a uniform positive electrode slurry, wherein LiFePO 4 , The weight ratio of polyvinylidene fluoride to carbon nanotubes is 92:3:5, and then the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, and the coating surface density is 1.4g / 100cm 2 , and then dried at 120°C to obtain the positive electrode sheet, and then rolled to control the thickness of the positive electrode sheet so that the compacted density was 2g / cm 3 , and finally made positive electrode pieces of 145mm×179mm through slitting. A...

Embodiment 2

[0120] Implement according to the method described in Example 1, the difference is that the thickness of the negative electrode sheet is rolled and controlled so that its compacted density is 1.2g / cm 3 .

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Abstract

The invention relates to the technical field of batteries, in particular to a lithium ion battery and a preparation method thereof. The lithium ion battery is characterized in that the lithium ion battery comprises a positive plate, a negative plate, a diaphragm, an electrolyte and a battery housing. The positive plate comprises a positive current collector and positive slurry, and the negative plate comprises a negative current collector and negative slurry, wherein the ratio of the capacity of the negative plate to the capacity of the positive plate is 1.41-9.41. According to the lithium ionbattery, the ratio of the capacity of the negative plate to the capacity of the positive plate in the battery is optimized, the surplus capacity is supplemented through a lithium supplementing technology, and the parameters of the positive plate and the negative plate are optimized, so that the cycle performance, the safety performance and the rate charging performance of the lithium ion batteryare improved, and the lithium ion battery has the characteristics of high rate and long service life.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a lithium ion battery and a preparation method thereof. Background technique [0002] At present, limited by the electrochemical performance and production cost of electrode materials, it is very difficult to increase the energy density of lithium-ion batteries and reduce the cost of battery raw materials. This is a key factor restricting the vigorous promotion of new energy vehicles. Improving the charging speed of lithium-ion batteries and shortening the charging time per unit of electricity is an effective way to enhance battery life. At the same time, optimizing the production process and improving production efficiency are the main means to reduce the cost of batteries. [0003] The production of lithium batteries mainly includes processes such as slurry preparation, coating, sheet production, assembly, liquid injection, chemical formation, and volume separation. The prep...

Claims

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Application Information

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IPC IPC(8): H01M10/0525H01M10/058H01M4/66H01M4/36H01M4/62
CPCH01M10/0525H01M10/058H01M4/667H01M4/362H01M4/621H01M4/624Y02E60/10Y02P70/50
Inventor 成新安徐平红李峰华王莉红
Owner FARASIS TECH (GANZHOU) CO LTD
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