Lithium ion battery cathode and lithium ion battery therewith

A lithium-ion battery and negative electrode technology, which is applied in the field of lithium-ion battery composition, can solve the problems of poor cycle life characteristics of lithium batteries, large changes in battery thickness, and poor adhesion of anode sheets, etc., to ensure long-term cycle performance. Good long-term cycle characteristics and the effect of reducing battery expansion rate

Inactive Publication Date: 2012-03-07
DONGGUAN AMPEREX TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the water-based negative electrode sheet of lithium-ion batteries generally uses styrene-butadiene rubber (SBR) as the binder, but the modulus of this binder is small, resulting in a large change in the thickness of the battery during the cycle. This is more obvious in pouch batteries, which obviously limits the application of lithium batteries; on the other hand, SBR has poor resistance to electrolytes, and once soaked in electrolytes, the bonding force is significantly weakened, so the anode during the cycle Lithium batteries exhibit poor cycle life characteristics due to poor sheet adhesion

Method used

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  • Lithium ion battery cathode and lithium ion battery therewith
  • Lithium ion battery cathode and lithium ion battery therewith
  • Lithium ion battery cathode and lithium ion battery therewith

Examples

Experimental program
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Embodiment 1

[0025] Negative sheet preparation process

[0026] Negative electrode slurry formula is based on dry material weight percentage, is made up of three parts: 2.5% sodium carboxymethyl cellulose (CMC-Na), 1.5% conductive carbon black, 96% negative electrode active material, wherein negative electrode active material adopts artificial graphite, carboxy Sodium methylcellulose has a number average molecular weight of about 500,000, a 1% aqueous solution viscosity of 150 mPa.s at 25°C, and a degree of substitution of 0.8. During the preparation of the slurry, the solvent is water, and water accounts for 60% of the total slurry.

[0027] First, add water and sodium carboxymethyl cellulose into the stirring grinder according to the above formula, and dissolve completely in a vacuum state, then add conductive carbon black into the dissolved water-based polymer solution according to the formula, and quickly stir and grind Until the fineness is below 5μm, finally add artificial graphite ...

Embodiment 2

[0036] The difference from Example 1 is that: the negative electrode formula contains 97.5% of the negative electrode active material, 1% of sodium carboxymethylcellulose, and 1.5% of conductive carbon black as an electrical conduction aid. Wherein the sodium carboxymethyl cellulose substitution degree that adopts is 1.0, molecular weight 1,000,000, its 1% aqueous solution 25 ℃ viscosity 1200mPa.s, other is identical with embodiment 1, repeats no more here.

Embodiment 3

[0038] The difference from Example 1 is that: the negative electrode formula contains 93.5% of the negative electrode active material, 5% sodium carboxymethyl cellulose, and 1.5% conductive carbon black as an electrical conduction aid. Wherein the sodium carboxymethylcellulose that adopts is 0.6, molecular weight 50,000, its 1% aqueous solution 25 ℃ viscosity 50mPa.s, other is identical with embodiment 1, repeats no more here.

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Abstract

The invention belongs to the field of lithium ion battery materials, and provides a lithium ion battery cathode comprising a current collector and a cathode material coated on eth current collector. The cathode material comprises a carbon material or an alloy material. An adopted binder is carboxymethylcellulose sodium. The carboxymethylcellulose sodium has a substitution degree of 0.6 to 1.2, and a number-average molecular weight of 50 thousands to 1 million. The viscosity of a 1% aqueous solution of carboxymethylcellulose sodium under a temperature of 25 DEG C is 50-1200mPa*s. The mass percentage of carboxymethylcellulose sodium in the cathode material is 1% to 5%. With a lithium ion battery employing the cathode, a defect of over-expended thickness during a battery circulation process is solved. Also, the produced battery is safe, reliable, and has a long circulation life.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and more specifically relates to a composition and a method of a lithium-ion battery with improved performance. Background technique [0002] Since its commercialization, lithium-ion batteries have been widely used as power sources for various mobile devices due to their high energy density, high working voltage, no memory effect, long cycle life, and no pollution to the environment. The practical phase of the scale. [0003] The characteristics of lithium-ion batteries can be developed by improving the components of the battery. The performance of the battery depends on the electrodes, electrolyte and battery materials contained therein, while the characteristics of the electrodes depend on the active materials, current collectors and binders of the battery. The agent provides the adhesion between the battery active material and the current collector. When the binder provides a stro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/62H01M10/0525
CPCY02E60/10
Inventor 邓耀明柳娜许瑞赖旭伦谭欣欣曾秋梅
Owner DONGGUAN AMPEREX TECH
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