Lithium ion battery cathode and lithium ion battery

A lithium-ion battery and negative electrode technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of poor rate performance, reduced cycle life, loose negative electrode active material layer, etc., and achieve a low expansion rate. , the effect of reducing the expansion rate

Active Publication Date: 2013-09-25
NINGDE AMPEREX TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the non-covalent bond (Van der Waals effect) force provided by the binder in the negative pole piece system will be reduced due to the swelling of the polymer binder to varying degrees under the electrolyte immersion. When the thickness of the pole piece increases or the selection of When using active materials with greater expansion (silicon, silicon oxide, etc.), this will cause the loosening and falling off of the negative electrode active material layer, which will make it difficult to deintercalate lithium ions, increase polarization, and lithium precipitation during cycling. Serious problems such as poor performance and reduced cycle life

Method used

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

Examples

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Effect test

Embodiment 1

[0034] Example 1, A lithium ion battery negative electrode, comprising a negative electrode current collector and a negative electrode active material layer coated on the negative electrode current collector, the negative electrode active material layer includes a negative electrode active material, a conductive agent, a polymer thickener, and an aqueous emulsion polymer binder and a water-soluble polymer binder, the water-soluble polymer binder is polyethyleneimine, and the weight ratio of the water-emulsion polymer binder to the water-soluble polymer binder is 10:90~90:10 .

[0035] Preparation of the negative electrode: The negative electrode slurry formula is calculated by weight percentage of the dry material, consisting of 2% styrene-butadiene rubber emulsion, 1.5% polyethyleneimine, 0.5% sodium carboxymethyl cellulose, 1% conductive carbon black, and 95% negative electrode active material Composed of five parts, the negative electrode active material is made of artifi...

Embodiment 2

[0047] Example 2, The difference from Example 1 is that the preparation process of the negative electrode of this embodiment is that the negative electrode slurry formula is calculated by weight percentage of dry material, consisting of 2% nitrile rubber emulsion, 1.5% butadiene rubber emulsion, 2% polyethyleneimine , 0.5% carboxymethyl cellulose, 1% carbon fiber, and 93% negative electrode active material. The negative electrode active material is made of natural graphite and graphitized carbon fiber. The weight average molecular weight of polyethyleneimine is about 100,000g / mol. The pH value of the aqueous solution with a mass concentration of 5% is in the range of 9-12, the degree of substitution of carboxymethyl cellulose is in the range of 0.8-1.0, and the viscosity of an aqueous solution with a mass concentration of 1% at 25°C is 1000 -3000mPa.s range. During the slurry preparation process, the solvent is deionized water, and water accounts for 60% of the total slurry ...

Embodiment 3

[0051] Example 3, The difference from Example 2 is that the preparation process of the negative electrode in this example is as follows: the negative electrode slurry formula is calculated by weight percentage of dry material, consisting of 2% butadiene rubber emulsion, 2% polyethyleneimine, 1% hydroxyethyl fiber It consists of five parts: element, 1% carbon nanotubes, and 94% negative electrode active material. The negative electrode active material uses graphitized mesophase carbon microbeads and amorphous carbon. The weight average molecular weight of polyethyleneimine is about 5,000 g / mol. The pH value of the aqueous solution with a mass concentration of 5% is in the range of 9 to 12, the degree of substitution of hydroxyethyl cellulose is in the range of 0.8-1.0, and the viscosity of an aqueous solution with a mass concentration of 1% at 25°C is 1000 -3000mPa.s range. During the slurry preparation process, the solvent is deionized water, and water accounts for 60% of th...

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Abstract

The invention discloses a lithium ion battery cathode. The lithium ion battery cathode comprises a cathode current collector and a cathode active-substance layer coated on the cathode current collector. The cathode active-substance layer comprises a cathode active-substance, a conductive agent, a polymer thickening agent, a water emulsion-type polymer binder and a water soluble polymer binder. The water soluble polymer binder is polyethyleneimine. A weight ratio of the water emulsion-type polymer binder to the water soluble polymer binder is in a range of (10: 90)-(90: 10). The lithium ion battery cathode can obviously improve the adhesion between the cathode active-substance layer and the cathode current collector and among particles in the cathode active-substance layer thereby improving structure stability of the cathode active-substance layer in long-term battery cycle and reducing a use amount of the polymer binders having electrochemical inertia, reducing a battery volume expansion ratio in cycle, and improving low temperature, multiplying power, cycle performances and energy density of a polymer lithium ion battery. The invention also discloses a lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode and a lithium ion battery. Background technique [0002] Since the promotion of commercialization, lithium-ion batteries have been widely used as a variety of portable electronic devices due to their high energy density, high working voltage, long cycle life, no memory effect, green environmental protection, and flexible design of size and shape according to actual needs. The power supply of electrical appliances, these broad application fields and various practical needs have greatly promoted the development of lithium-ion batteries. [0003] With the rapid development of mobile electronic and electrical equipment, lithium-ion batteries that provide power for these thin, portable and powerful devices are required to have higher capacity. Therefore, it is necessary to develop higher operating voltage, higher energ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/13H01M10/0525
CPCY02E60/10
Inventor 平翔梁如福陈永乐王景芳张柏清
Owner NINGDE AMPEREX TECH
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