Lithium ion battery silicon-carbon negative electrode binder, and negative electrode sheet and preparation method thereof

A lithium-ion battery and negative pole piece technology, which is applied in the direction of electrode manufacturing, battery electrodes, negative electrodes, etc., can solve the problems of decreased adhesion of coating layers, uneven distribution of binders, high production costs, etc., to achieve inhibition of migration, The effect of reducing production cost and improving battery performance

Active Publication Date: 2020-12-04
WANXIANG 123 CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to overcome the problems that the traditional negative electrode coating and baking process easily causes uneven distribution of the binder in the longitudinal direction of the pole piece, the adhesion of the coating layer is reduced, and the production cost is high, the invention provides a silicon-carbon negative electrode bonding method for lithium ion batteries. agent

Method used

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  • Lithium ion battery silicon-carbon negative electrode binder, and negative electrode sheet and preparation method thereof
  • Lithium ion battery silicon-carbon negative electrode binder, and negative electrode sheet and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] (1) According to the following ratio, use a conventional double planetary homogenizer to homogenize polyallylamine hydrochloride (PAH) and polyacrylic acid-polybenzimidazole (PAA-PBI) at a high speed according to the molar ratio of 20:80 Make glue in the slurry machine, add conductive additives, silicon carbon active materials and water in sequence to obtain the negative electrode slurry; based on the total mass of the negative electrode slurry, the negative electrode slurry is composed of the following components in mass percentage: negative electrode binder (polyallylamine hydrochloride (PAH) and polyacrylic acid-polybenzimidazole (PAA-PBI)) 1.5%, silicon carbon active material (5wt% average particle diameter is the nano silicon of 100nm and 95wt% artificial Graphite) 95%, carbon nanotube 0.5%, water surplus; The viscosity of negative electrode slurry is controlled at 3000mpa.s; Solid content is controlled at 50wt%;

[0040] (2) if figure 2 As shown, the negative el...

Embodiment 2

[0045] (1) According to the following ratio, use a conventional double planetary homogenizer, glue polyallylamine hydrochloride (PAH) in a high-speed homogenizer, and add conductive additives, silicon carbon active materials and water in sequence , get the negative electrode slurry; take the negative electrode slurry gross mass as a benchmark, the negative electrode slurry is made up of the following mass percentage components: polyallylamine hydrochloride (PAH) 5%, silicon carbon active material (average of 20wt%) Particle size is 300nm nano-silicon and 80wt% artificial graphite) 80%, Ketjen black 0.5%, carbon black 1.5%, water surplus; The viscosity of negative electrode slurry is controlled at 7500mpa.s; Solid content is controlled at 38wt%;

[0046] (2) if figure 2 As shown, the negative electrode slurry is evenly coated on the upper base material layer, and the coating amount is controlled at 250g / m 2 The thickness of the base material layer is 5 μm; the three-stage dry...

Embodiment 3

[0051] (1) According to the following proportions, using a conventional double planetary homogenizer, polyacrylic acid-polybenzimidazole (PAA-PBI) is glued in a high-speed homogenizer, and conductive additives, silicon carbon active materials and Water, get negative electrode slurry; Taking negative electrode slurry gross mass as benchmark, described negative electrode slurry is made up of the component of following mass percent: polyacrylic acid-polybenzimidazole (PAA-PBI) 5%, silicon carbon active material ( 15% average particle diameter is 20nm nano-silicon and 85wt% artificial graphite) 95%, carbon black 3.5%, solvent balance; The viscosity of negative electrode slurry is controlled at 2100mpa.s; Solid content is controlled at 62wt%;

[0052] (2) if figure 2 As shown, the negative electrode slurry is evenly coated on the upper base material layer, and the coating amount is controlled at 80g / m 2 The thickness of the base material layer is 15 μm; the three-stage drying is ...

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Abstract

The invention relates to the technical field of lithium ion batteries, provides a lithium ion battery silicon-carbon negative electrode binder, and a negative electrode sheet and a preparation methodthereof, and aims to solve the problems of uneven distribution of a binder in the longitudinal direction of an electrode sheet, reduction of the adhesive force of a coating layer and high production cost easily caused by a traditional negative electrode coating and baking process. The lithium ion battery silicon-carbon negative electrode binder is selected from one or a combination of two of polyallylamine hydrochloride and polyacrylic acid polybenzimidazole. According to the invention, by adopting the novel polymer binder and optimizing the electrode sheet drying process, the migration of thebinder in the electrode sheet is effectively inhibited, the longitudinal distribution uniformity of the binder in the negative electrode sheet is improved, the battery performance is improved, the electrode sheet baking time is shortened, and the battery manufacturing cost is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a silicon-carbon negative electrode binder for lithium-ion batteries, a negative electrode sheet and a preparation method. Background technique [0002] Silicon-carbon composite materials have become one of the development directions of lithium-ion battery anode materials in the future due to their high energy density. However, the volume of silicon anodes expands significantly during charging and discharging, resulting in increased volume of lithium-ion batteries, decreased cycle life, and internal short circuits. Safety issues. The silicon carbon active material and the conductive additive can be bonded together by the polymer binder, and the coating layer and the current collector can be combined to maintain the structural integrity of the negative electrode during the charge and discharge cycle and improve the overall performance of the battery. The drying speed...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/133H01M4/134H01M4/04H01M4/1393H01M4/1395H01M10/0525B05D3/02
CPCH01M4/622H01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/0471H01M10/0525B05D3/0263H01M2004/027Y02E60/10
Inventor 宫娇娇资小林许梦清高明霞
Owner WANXIANG 123 CO LTD
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