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Composite negative plate and preparation method thereof, and secondary battery

A technology of negative electrode sheet and conductive agent, which is applied in the direction of secondary battery, negative electrode, battery electrode, etc., can solve the problem that the negative electrode sheet is difficult to increase capacity and cycle stability at the same time, and achieve the effect of improving stability

Pending Publication Date: 2021-11-12
EVERGRANDE NEW ENERGY TECH SHENZHEN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a composite negative electrode sheet and its preparation method, as well as a secondary battery, aiming to solve the problem that the existing negative electrode sheet is difficult to improve capacity and cycle stability at the same time

Method used

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  • Composite negative plate and preparation method thereof, and secondary battery
  • Composite negative plate and preparation method thereof, and secondary battery
  • Composite negative plate and preparation method thereof, and secondary battery

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preparation example Construction

[0074] as attached figure 2 As shown, the second aspect of the embodiment of the present invention provides a method for preparing a composite negative electrode sheet, comprising the following steps:

[0075] S10. After the carbon active layer is prepared on the surface of the current collector, the carbon active layer is subjected to pore-forming treatment, and a number of micropores are opened on the surface of the carbon active layer; the opening depth of the micropores is lower than the thickness of the carbon active layer;

[0076] S20. Fill the micropores with the mixed slurry of the second active material, and dry to obtain a composite negative electrode sheet; wherein, the specific capacity of the second active material is higher than that of the carbon material in the carbon active layer.

[0077] In the preparation method of the composite negative electrode sheet provided by the second aspect of the embodiment of the present invention, after the carbon active layer...

Embodiment 1

[0099] A kind of composite negative plate , its preparation includes the steps of:

[0100]1. Mix graphite powder with a particle size D50 of 12 microns with carbon black powder, CMC and SBR, and stir to make graphite negative electrode slurry. The content of graphite powder is 85%, the content of carbon black is 5%, and the binder CMC and SBR content is 10%.

[0101] 2. Take the graphite negative electrode slurry prepared in step (1), apply it on the copper foil, and dry it to obtain the negative electrode. Increase the density of the graphite negative electrode to 1.6 g / cm by rolling, etc. 3 .

[0102] 3. The graphite negative electrode with a thickness of 110 μm obtained in step (2) is punched out by pulsed laser ablation into a square array of holes with a diameter of 60 μm and a hole depth of 100 μm.

[0103] 4. Mix silicon oxide powder with a particle size D50 of 5 microns, carbon black powder, and binder PAA, and stir to make a silicon oxide negative electrode slur...

Embodiment 2

[0107] A kind of composite negative plate , which differs from Example 1 in that: in step 4, silicon powder is used instead of silicon-oxygen powder.

[0108] a secondary battery , Assemble the composite negative electrode sheet prepared in Example 2, NCM811 positive electrode sheet, 12+4 ceramic diaphragm, and high-nickel electrolyte into a pouch battery. The designed battery capacity is 9Ah, and the battery size is 80*60*8.55mm.

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Abstract

The invention belongs to the technical field of batteries, and particularly relates to a composite negative plate and a preparation method thereof, and a secondary battery. The composite negative plate comprises a current collector and a carbon active layer combined on the surface of the current collector, a plurality of micropores are formed in the surface, deviating from the current collector, of the carbon active layer, the micropores are filled with a second active material, and the specific capacity of the second active material is higher than that of a carbon material in the carbon active layer; and the opening depth of the micropores is lower than the thickness of the carbon active layer. According to the composite negative plate disclosed by the invention, through the synergistic effect of the carbon active layer and the second active material which is filled in the micropores and has higher a specific capacity, the capacity of the composite negative plate can be improved so that the capacity density of the battery is improved, and the volume expansion effect of the active material can be relieved or even inhibited through the carbon active layer; and the microporous structure is also beneficial to improving the ion migration transmission efficiency, improving the electrolyte retention capacity of the pole piece and improving the electrochemical performance of the composite pole piece.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a composite negative electrode sheet, a preparation method thereof, and a secondary battery. Background technique [0002] Lithium-ion batteries are rechargeable batteries widely used in the fields of power, energy storage and consumption at present. The positive electrodes are mostly transition metal oxide lithium salts such as lithium cobalt oxide (LCO) and nickel cobalt lithium manganese oxide (NCM), or Lithium Iron Phosphate (LFP) and Lithium Manganese Phosphate (LMP) are transition metal lithium salts of phosphate; the negative electrode mostly uses graphite-based carbon materials. In order to further increase the specific energy of the battery, new anode materials such as silicon, tin, and silicon-oxygen materials, whose theoretical specific capacity is 5 to 10 times higher than graphite-based carbon materials, have attracted increasing attention. However, si...

Claims

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Application Information

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IPC IPC(8): H01M4/133H01M4/1393H01M4/36H01M4/587H01M4/62H01M10/0525
CPCH01M4/133H01M4/1393H01M4/362H01M4/587H01M4/621H01M4/625H01M10/0525H01M2004/027Y02E60/10
Inventor 张惠李硕李展鹏庄堃毅
Owner EVERGRANDE NEW ENERGY TECH SHENZHEN CO LTD
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