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Negative electrode sheet and lithium ion battery

A technology of negative electrode sheet and negative electrode diaphragm, which is applied in the direction of battery electrodes, secondary batteries, circuits, etc., can solve the problems of reducing battery energy density, low compaction density, and low first effect, so as to improve rate performance, reduce DCR, Effect of Reducing Cycle Expansion Rate

Active Publication Date: 2019-11-29
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the prior art, the method for reducing the OI value of the pole piece is to select negative electrode active materials with a strong isotropic secondary particle structure, but compared with the primary particle structure, the secondary particle structure has low compaction density, low first effect, The disadvantage of low capacity, which reduces the energy density of the battery

Method used

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  • Negative electrode sheet and lithium ion battery

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preparation example Construction

[0022] Next, the preparation method of the negative electrode sheet according to the second aspect of the present invention will be described. A method for preparing the negative electrode sheet according to the second aspect of the present invention is used to prepare the negative electrode sheet described in the first aspect of the present invention, comprising the steps of: dissolving the thickener in a solvent (such as deionized water) to obtain the thickener solution; the binder is dissolved in a solvent (such as deionized water) to obtain a binder solution; after the thickener solution is mixed with the binder solution, the negative electrode active material is added, stirred evenly to obtain a negative electrode slurry, and the negative electrode slurry After being coated on the current collector, the negative electrode sheet can be obtained after drying. Wherein, the mass fraction of the thickener solution may be 0.1%-10%. The mass fraction of the binder solution may ...

Embodiment 1

[0029] (1) Preparation of negative electrode sheet

[0030] Weigh PAA solid powder with a weight-average molecular weight of about 10 million as a thickener, add deionized water, stir at a high speed, and prepare a 1.5% thickener solution for use.

[0031] Weigh the SBR emulsion with a weight-average molecular weight of about 15 million as a binder, add deionized water, stir at a high speed, and prepare a 40% binder solution for use.

[0032] Thickener solution, binder solution are mixed, add negative electrode active material graphite to obtain negative electrode slurry, control the mass ratio of negative electrode active material graphite, thickener PAA, binding agent SBR to be 94:4:2, negative electrode slurry The material is coated on both sides of the current collector copper foil (thickness is 10μm), and the coating weight is 165mg / 1540.25mm 2 (compaction density 1.75g / cm3), after drying, rolling, cutting, and welding the negative electrode tabs, the negative electrode ...

Embodiment 2

[0042] The preparation process of the lithium-ion battery is the same as in Example 1, except that the weight average molecular weight of PAA is about 14 million.

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Abstract

An anode sheet and a lithium ion battery are provided. The anode sheet includes an anode membrane sheet and a current collector. The anode membrane sheet includes a thickener, an adhesive and an anodeactive material. The weight-average molecular weight of the thickener is 10 million to 20 million. The weight-average molecular weight of the adhesive is 5 million to 20 million. The anode active material includes graphite. When the anode sheet is applied in the lithium ion battery, cyclic expansion and DCR of the lithium ion battery are effectively reduced, and the rate capacity of the lithium ion battery can be improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a negative electrode sheet and a lithium ion battery. Background technique [0002] The current rapid development of smart phones requires high energy density of mobile phone batteries, as well as high requirements for fast charging and heat generation of mobile phone batteries. Moreover, due to the aesthetic needs of smart phones, mobile phone batteries are required to be thinner and thinner, which requires battery During use, no large expansion can be generated, and unnecessary space should be minimized. [0003] The rapid charging, heat generation and cycle expansion of mobile phone batteries have a great relationship with the negative electrode active material. The OI value is an important indicator of the low expansion characteristics of graphite negative active materials. The peak intensity (I110) of the surface (110) and the peak intensity (I004) of the surface (004) ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/133H01M4/62H01M4/583H01M10/0525
CPCY02E60/10
Inventor 谢锐崔航谢远森
Owner NINGDE AMPEREX TECH