Preparation method of lithium battery positive plate, positive plate and lithium ion battery

A positive electrode sheet and lithium battery technology, which is applied to battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of fracture and brittle cracks of the positive electrode sheet, and achieve the goal of improving flexibility and solving the problem of brittle fracture Effect

Pending Publication Date: 2022-08-05
陈钦湘
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] One of the objectives of the present invention is to provide a method for preparing a positive electrode sheet of a lithium battery to solve the problem that the above positive electrode sheet is prone to embrittlement or fracture during processing

Method used

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  • Preparation method of lithium battery positive plate, positive plate and lithium ion battery
  • Preparation method of lithium battery positive plate, positive plate and lithium ion battery

Examples

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Effect test

preparation example Construction

[0032] Based on the above ideas, one of the objectives of the present invention is to provide a method for preparing a positive electrode sheet for a lithium battery, comprising the following steps:

[0033] (1) Mix the active material with the conductive agent, the binder and the solvent according to a certain proportion, and make a slurry after stirring;

[0034] (2) drying the slurry evenly on the surface of the current collector, and then winding to obtain a pole roll;

[0035] (3) Roll film processing on the pole roll;

[0036] (4) slitting and slicing the pole roll to obtain a positive electrode sheet;

[0037] The relative humidity of one or more of the steps (2) to (4) is 25% to 100%.

[0038] By controlling the relative humidity of the environment in one or more steps of (2) to (4) from 25% to 100%, the aqueous binder in the positive electrode sheet absorbs moisture in the air, so that the polymer segment of the aqueous binder can be obtained. Fully stretch, improv...

Embodiment 1

[0050] A method for preparing a positive electrode sheet for a lithium battery, comprising the following steps:

[0051] (1) Mix the active material with the conductive agent, the binder and the solvent according to a certain proportion, and make a slurry after stirring;

[0052] (2) drying the slurry evenly on the surface of the current collector, and then winding to obtain a pole roll;

[0053] (3) Roll film processing on the pole roll;

[0054] (4) slitting the pole roll to obtain the positive electrode sheet 1;

[0055] The relative humidity of one or more of the steps (2) to (4) is 25% to 100%.

[0056] Flexibility performance (or brittle fracture performance) test: Take a positive electrode sheet 1 with a width of 15mm, 2.30g / ~2.35g / cm3, water content of 1000~1500ppm, and under the environment of relative humidity within 1%, fold the positive electrode sheet 180 degrees in half, and then Roll a 5kg solid steel rod, flatten the positive electrode sheet, observe whether...

Embodiment 2

[0058] The preparation method is the same as in Example 1. The difference is: in step (2), the relative humidity is 100%, and the positive electrode sheet 2 is prepared.

[0059] Flexibility performance (or brittle fracture performance) test: Take positive electrode sheet 2 with a width of 15mm, 2.30g / ~2.35g / cm3, water content of 1000~1500ppm, and under the environment of relative humidity within 1%, fold the positive electrode sheet in half at 180 degrees, and then Roll the 5kg solid steel rod, flatten the positive electrode sheet, observe whether the positive electrode sheet is light-transmitting, fold the positive electrode sheet in half at 180 degrees, and then roll it with a 5kg solid steel rod, flatten the positive electrode sheet, observe whether the positive electrode sheet is light-transmitting, record Repeat the number of times to determine whether the positive electrode sheet begins to crack.

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Abstract

The invention provides a lithium battery positive plate preparation method, which comprises: (1) mixing a positive electrode active material, a conductive agent, a water-based binder and a solvent according to a certain ratio, and stirring to prepare a slurry; (2) uniformly coating the slurry on the surface of a current collector, drying, and then rolling to obtain a pole roll; (3) carrying out film rolling treatment on the pole roll; (4) carrying out slitting and slicing treatment on the pole roll to prepare a pole piece; wherein the relative humidity of one or more procedures of the steps (2)-(4) is 25%-100%. According to the invention, by controlling the environment relative humidity of one or more procedures (2)-(4) to be 25-100%, the aqueous binder in the positive plate absorbs moisture in air, so that a polymer crystal chain segment of the aqueous binder is fully stretched, the flexibility of the pole plate is improved, and the problem of brittle failure of the pole plate in the processing process is solved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of a positive electrode sheet of a lithium battery, a positive electrode sheet and a lithium ion battery. Background technique [0002] Binders are an important part of lithium-ion batteries. They help positive and negative electrode active materials and conductive agents adhere to the surface of current collectors to form positive and negative electrode sheets. They are an indispensable part of the composition of lithium-ion batteries. [0003] The water-based adhesives currently used in the industry (water as a solvent, can be uniformly and stably dispersed in water without the emulsifier itself), such as polyacrylic acid water-based adhesives, polyacrylic acid and acrylonitrile copolymerized water-based adhesives Binder, polyvinyl alcohol water-based binder, water-based polyurethane binder, carboxymethyl chitosan-modified water-based binder, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/139H01M4/13H01M4/62H01M10/0525
CPCH01M4/139H01M4/622H01M4/0404H01M4/0435H01M4/0471H01M4/13H01M10/0525Y02E60/10
Inventor 陈钦湘
Owner 陈钦湘
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