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

A technology of lithium ion battery and negative pole piece, which is applied to battery electrodes, non-aqueous electrolyte battery electrodes, negative electrodes, etc., can solve the problems of loose structure, increased local thickness, easy collapse, etc. Cyclic performance, the effect of reducing swelling deformation

Active Publication Date: 2016-08-17
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, during the use of lithium-ion batteries, the cell body will experience irreversible deformations such as bumps, waves, or local thickness increases. When the deformation is severe, electronic mobile terminal equipment cannot accommodate lithium-ion batteries, which may break the device and affect the device. normal use
After research, it is found that the reasons for the above problems mainly include the following three aspects: (1) When winding the battery core, there is no extra space reserved between the pole piece and the separator, resulting in the inside of the wound battery core having Large internal stress; (2) After the prepared lithium-ion battery is charged and discharged, the thickness of the negative electrode sheet increases significantly due to lithium intercalation; (3) In the process of coating the active material slurry on the current collector, Due to the high bond strength of the binder used in the active material paste, shrinkage occurs after coating is complete
[0004] In view of the above problems, the current improvement method is to coat a porous polyvinylidene fluoride (PVDF) layer on the surface of the negative electrode active material layer, but the structure of the traditional porous polyvinylidene fluoride (PVDF) is relatively loose and easy to collapse. Therefore, lithium The deformation problem of ion batteries is still not well solved

Method used

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

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preparation example Construction

[0029] According to the second aspect of the present invention, the preparation method of the negative electrode sheet of the lithium ion battery includes the steps of: (1) fully mixing the negative electrode active material, the negative electrode conductive agent, the negative electrode binder and the negative electrode dispersant according to an appropriate proportion to obtain the negative electrode active material Slurry, the negative electrode active material slurry is coated on the negative electrode current collector, and the negative electrode active material layer is obtained after drying; (2) the porous ionic polymer and the polyimide monomer are dispersed in an organic solvent, and the Stir to obtain the composite slurry; (3) Coat the composite slurry on the surface of the negative electrode active material layer, after drying, heat and keep warm under vacuum or under the protection of protective gas to polymerize the polyimide monomer, cool After that, a polyimide-...

Embodiment 1

[0047] A negative electrode sheet preparation

[0048] (1) Fully mix the negative electrode active material natural graphite, the conductive agent conductive carbon black, the binder styrene-butadiene rubber and the dispersant sodium carboxymethyl cellulose according to the mass ratio of 96:1:2:1 to obtain the negative electrode active material slurry , coating the negative electrode active material slurry on a negative electrode current collector copper foil with a thickness of 12 μm, and drying at 100° C. for 5 hours to obtain a negative electrode active material layer with a thickness of 90 μm.

[0049] (2) Dissolve porous polyvinylidene fluoride (PVDF) with a porosity of 41.2% in advance with N-methylpyrrolidone (NMP), wherein the mass of porous polyvinylidene fluoride (PVDF) accounts for 7% of the total mass of the solution, and then Add the polyimide monomer accounting for 1% by mass of the solution, wherein the polyimide monomer is a premix of monomer A and monomer B an...

Embodiment 2

[0056] A negative electrode sheet preparation

[0057] (1) Fully mix the negative electrode active material natural graphite, the conductive agent conductive carbon black, the binder styrene-butadiene rubber and the dispersant sodium carboxymethyl cellulose according to the mass ratio of 96:1:2:1 to obtain the negative electrode active material slurry , coating the negative electrode active material slurry on a negative electrode current collector copper foil with a thickness of 12 μm, and drying at 100° C. for 5 hours to obtain a negative electrode active material layer with a thickness of 90 μm.

[0058] (2) Dissolve porous polyvinylidene fluoride (PVDF) with a porosity of 52.2% in advance with N-methylpyrrolidone (NMP), wherein the mass of porous polyvinylidene fluoride (PVDF) accounts for 7% of the total mass of the solution, and then Add the polyimide monomer accounting for 2% by mass of the solution, wherein the polyimide monomer is a premix of monomer A and monomer B an...

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Abstract

The invention provides a lithium ion battery, a negative electrode pole piece and a preparation method of the lithium ion battery. The negative electrode pole piece of the lithium ion battery comprises a negative electrode current collector, a negative electrode active material layer and a modified porous ionic polymer layer, wherein the negative electrode active material layer comprises a negative electrode conductive agent, a negative electrode bonding agent and a negative electrode active material and is arranged on the negative electrode current collector in a coating manner, the modified porous ionic polymer layer is a modified polyimide porous ionic polymer layer and is arranged on the surface of the negative electrode active material layer in a coating manner. The lithium ion battery comprises the negative electrode pole piece. According to the invention, the deformation rate of the lithium ion battery is reduced and the cycling performance and overcharge resistance of the lithium ion battery are increased.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a lithium-ion battery, a negative pole piece thereof and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used in portable electronic devices and electric vehicles because of their high energy density and environmental friendliness. [0003] However, during the use of lithium-ion batteries, the cell body will experience irreversible deformations such as bumps, waves, or local thickness increases. When the deformation is severe, electronic mobile terminal equipment cannot accommodate lithium-ion batteries, which may break the device and affect the device. normal use. After research, it is found that the reasons for the above problems mainly include the following three aspects: (1) When winding the battery core, there is no extra space reserved between the pole piece and the separator, resulting in the inside of the wound battery core havi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/62H01M4/139H01M10/0525
CPCH01M4/13H01M4/139H01M4/622H01M10/0525H01M2004/027Y02E60/10
Inventor 郑义孙成栋江辉
Owner NINGDE AMPEREX TECH
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