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A kind of high safety lithium-ion battery negative electrode composite material and preparation method thereof

A lithium-ion battery and composite material technology, which is applied in the field of high-safety lithium-ion battery negative electrode composite materials and their preparation, can solve the problems of heat dissipation performance deviation, safety performance deviation, inability to realize the self-closing function of materials, etc., and achieves improved safety performance. , the effect of preventing thermal runaway

Active Publication Date: 2021-04-09
CHENGDU EMINENT NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For example, patent CN105390678 A discloses a negative electrode material and a lithium ion battery including the negative electrode material, wherein the negative electrode material includes a base material and a coating layer located on the surface of the base material, the base material is a negative electrode active material, and the coating layer includes a material selected from PEDOT, PSS At least one of the above-mentioned substances, after the negative electrode material is applied to the lithium-ion battery, the safety performance, high-temperature storage performance, high-temperature cycle performance and excellent rate performance of the lithium-ion battery are improved, but the thermal runaway of the material occurs when the temperature is too high When the heat dissipation performance deviation of the material cannot realize the self-closing function of the material, resulting in the deviation of its safety performance

Method used

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  • A kind of high safety lithium-ion battery negative electrode composite material and preparation method thereof
  • A kind of high safety lithium-ion battery negative electrode composite material and preparation method thereof
  • A kind of high safety lithium-ion battery negative electrode composite material and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0017] A high-safety lithium-ion battery negative electrode composite material includes an inner core and a cladding layer covering the inner core, the inner core is graphite, the cladding layer is a thermally denatured composite material, and the thickness of the cladding layer is 0.5-1 μm. The thickness of the coating layer is too thin. When the heat-denatured material melts or swells, the pores between the particles cannot be effectively reduced or disappeared, and the thermal shutdown effect cannot be realized, and the thermal runaway of the battery cannot be prevented, which is detrimental to the safety performance of the lithium-ion battery; If the coating layer is too thick, when the thermally denatured material melts or swells, the pores between the particles can disappear quickly, which can realize the thermal shutdown effect and effectively prevent the thermal runaway of the battery. There is no reaction to lithium ions, too thick a coating layer will directly affect ...

Embodiment 2

[0023] Based on the structures and components of the above-mentioned embodiments, this embodiment discloses a specific example.

[0024] A. Preparation of thermally denatured composite material coating solution: Add 45g of polyvinyl alcohol to 100g of N-methylpyrrolidone organic solvent, stir evenly, then add 55g of ethylene-vinyl acetate copolymer to dissolve evenly, and then add 3g Aminated graphene, 0.7g ammonium benzenesulfonate, and 0.3g ethylene glycol monobutyl ether were uniformly dispersed by ultrasonic to obtain a uniform coating solution.

[0025] B. Weigh 150g of artificial graphite with a particle size of 8 µm, add it to the coating solution A and disperse it evenly through a ball mill, dry, pulverize, and classify to obtain a graphite composite material with a small particle size, and then mix the composite material B Transfer to a tube furnace, first pass argon gas to exhaust the gas in the tube, and then pass SO 2 Gas, the flow rate is 2ml / min, and the tempera...

Embodiment 3

[0027] Based on the structure and components of Embodiment 1, this embodiment discloses a specific example.

[0028] A. Preparation of thermally denatured composite material coating solution: Add 40g of polyvinyl alcohol to 100g of N-methylpyrrolidone organic solvent, stir evenly, then add 60g of ethylene-vinyl acetate copolymer to dissolve evenly, and then add 1g Aminated graphene, 0.3 g of ammonium benzenesulfonate, and 0.2 g of ethylene glycol monobutyl ether were uniformly dispersed by ultrasonic to obtain a uniform coating solution.

[0029] B. Weigh 100g of artificial graphite with a particle size of 5 µm, add it to the coating solution A and disperse it evenly through a ball mill, dry, pulverize, and classify to obtain a graphite composite material with a small particle size, and then mix the composite material B Transfer to a tube furnace, first pass argon gas to exhaust the gas in the tube, and then pass SO 2 Gas, the flow rate is 10ml / min, and the temperature is rai...

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Abstract

The invention discloses a high-safety lithium-ion battery negative electrode composite material and a preparation method thereof. The negative electrode composite material includes an inner core and a coating layer coated outside the inner core, the inner core is graphite, and the coating layer is thermal The composite material is modified and the thickness of the cladding layer is 0.5-1 µm. By coating the surface of the material with a thermally denatured material, the pores between the particles and the particles at room temperature can be ensured by using the melting point or softening point of the thermally denatured material to ensure the smooth back-and-forth insertion of lithium ions without affecting the internal resistance of the battery and the charge-discharge efficiency of the rate. When the temperature of the battery rises, the heat-denatured material melts or swells in a short time, and the pores between the particles rapidly become smaller or disappear, realizing the thermal shutdown effect, cutting off the lithium ion transmission channel, preventing the battery from thermal runaway, and improving its lithium ion performance. Safety performance of ion batteries.

Description

technical field [0001] The invention relates to the field of preparation of lithium-ion battery materials, in particular to a high-safety lithium-ion battery negative electrode composite material and a preparation method thereof. Background technique [0002] With the increasing market demand for lithium-ion batteries with high specific energy density, lithium-ion batteries are required to have high specific energy density and long cycle life under the premise of ensuring the safety performance of batteries. The negative electrode material is the key factor affecting the safety performance and energy density of lithium-ion batteries. The current market-oriented negative electrode materials are mainly graphite, although graphite materials are characterized by their low price, high stability, and excellent cycle performance. Due to its advantages, it has become the material of choice for lithium-ion batteries. However, lithium-ion batteries are prone to lithium precipitation a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/587H01M10/0525
CPCH01M4/587H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 董昭青王刚伏红松王圆方高川
Owner CHENGDU EMINENT NEW ENERGY TECH CO LTD
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