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Composite diaphragm with lithium supplementing effect, and preparation method thereof and lithium ion battery

A technology of lithium-ion batteries and composite diaphragms, applied in the field of lithium supplementation for lithium batteries, which can solve the problems of cumbersome procedures, the effect needs to be improved, and the difficulty in realizing accurate lithium supplementation of the negative electrode.

Pending Publication Date: 2021-04-02
TIANJIN ENERGIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process of this method is cumbersome, and may affect the performance of the electrolyte, thereby affecting the performance of the battery, and does not help to improve the safety of the battery.
Patent CN109888192A discloses a method for replenishing lithium on the negative electrode sheet of a lithium ion battery. The negative electrode sheet is contacted with lithium bicarbonate solution and then dried to obtain a lithium-enriched negative electrode sheet. Then the lithium-enriched negative electrode sheet, positive electrode sheet, separator and electrolysis Assembled and then chemically formed to obtain the required lithium-ion battery, the effect of this negative electrode lithium replenishment method needs to be improved, and it is difficult to achieve accurate lithium replenishment of the negative electrode

Method used

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  • Composite diaphragm with lithium supplementing effect, and preparation method thereof and lithium ion battery
  • Composite diaphragm with lithium supplementing effect, and preparation method thereof and lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) According to the ratio of 95% of ceramic powder and 5% of binder, weigh alumina powder and polyvinylidene fluoride powder and disperse them in NMP to prepare ceramic slurry, and obtain a ceramic slurry with a solid content of 75%. , use a gravure coater to evenly coat the ceramic slurry on both surfaces of the 10 μm PE base film, and obtain a ceramic separator with a thickness of 16 μm after drying, wherein the thickness of the ceramic coating on each surface is 3 μm,

[0035] (2) Negative active material (a mixture of graphite and silicon, capacity C 负 =500mAh g -1 , first coulombic efficiency ICE=80%), pre-lithiated design capacity C 设 It is 90% of the irreversible capacity of the silicon-carbon negative electrode, and the surface density of the pole piece ρ 负面 = 20 mg cm -2 , pole piece area S 负面 =82cm 2 , the specific capacity of metal lithium powder is C Li =3600mAh g -1 , the mass M of lithium metal powder required can be accurately calculated according...

Embodiment 2

[0038] (1) According to the ratio of 95% of ceramic powder and 5% of binder, weigh alumina powder and polyvinylidene fluoride powder and disperse them in NMP to prepare ceramic slurry, and obtain a ceramic slurry with a solid content of 75%. , use a gravure coater to evenly coat the ceramic slurry on both surfaces of the 10 μm PE base film, and obtain a ceramic separator with a thickness of 16 μm after drying, wherein the thickness of the ceramic coating on each surface is 3 μm,

[0039] (2) Negative active material (a mixture of graphite and silicon, capacity C 负 =500mAh g -1 , first coulombic efficiency ICE=80%), pre-lithiated design capacity C 设 It is 100% of the irreversible capacity of the silicon carbon negative electrode, and the surface density ρ of the pole piece 负面 = 20 mg cm -2 , pole piece area S 负面 =82cm 2 , the specific capacity of metal lithium powder is C Li =3600mAh g -1 , the mass M of lithium metal powder required can be accurately calculated accordin...

Embodiment 4

[0045] (1) According to the ratio of 95% of ceramic powder and 5% of binder, weigh alumina powder and polyvinylidene fluoride powder and disperse them in NMP to prepare ceramic slurry, and obtain a ceramic slurry with a solid content of 75%. , use a gravure coater to evenly coat the ceramic slurry on both surfaces of the 10 μm PE base film, and obtain a ceramic separator with a thickness of 16 μm after drying, wherein the thickness of the ceramic coating on each surface is 3 μm,

[0046] (2) Negative active material (a mixture of graphite and silicon, capacity C 负 =500mAh g -1 , first coulombic efficiency ICE=80%), pre-lithiated design capacity C 设 It is 100% of the irreversible capacity of the silicon carbon negative electrode, and the surface density ρ of the pole piece 负面 = 20 mg cm -2 , pole piece area S 负面 =82cm 2 , the specific capacity of metal lithium powder is C Li =3600mAh g -1 , the mass M of lithium metal powder required can be accurately calculated accordin...

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Abstract

The invention provides a composite diaphragm with a lithium supplementing effect. The composite diaphragm comprises a base membrane, a first ceramic coating and a second ceramic coating which are respectively positioned on the upper surface and the lower surface of the base membrane, a lithium supplementing gel coating positioned on the upper surface of the first ceramic coating, and a gel coatingpositioned on the lower surface of the second ceramic coating. According to the invention, with the ceramic coating in the diaphragm, the temperature resistance of the diaphragm is improved, the thermal shrinkage of the diaphragm is improved, explosion caused by short circuit due to direct contact between a positive electrode and a negative electrode due to diaphragm deformation caused by thermalcontraction of the diaphragm at a high temperature is prevented, the lithium supplementing gel coating can realize uniform and accurate lithium supplementing of a silicon-carbon negative electrode sheet, a silicon-carbon negative electrode is prevented from being excessively lithiated to cause lithium precipitation, after lithium supplementing is finished, the gel coating and the electrode sheethave higher bonding force under the action of hot-pressing shaping, and the lithium ion good conductor powder remained in the lithium supplementing coating has good ionic conductivity, so that the conduction of lithium ions is promoted.

Description

technical field [0001] The invention belongs to the technical field of lithium supplementation for lithium batteries, and in particular relates to a composite diaphragm with lithium supplementation effect, a preparation method thereof and a lithium ion battery. Background technique [0002] In the prior art, in the patent CN102610861A, the metal lithium strip is directly pressed on the surface of the negative electrode sheet, and under the infiltration of the electrolyte, the lithium strip is used as the negative electrode sheet for lithium supplementation, which reduces the irreversible capacity loss of the first charge and improves the energy density of the battery . The solid copper and aluminum foil used in the current collector needs to be compounded with lithium sheets on the surface of each negative electrode sheet. Currently, the lithium strips on the market are relatively thick. Due to the soft texture of lithium metal, the lithium strips are rolled into lithium foi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/449H01M50/434H01M50/431H01M50/403H01M10/0525H01M10/42
CPCH01M10/0525H01M10/4242Y02E60/10
Inventor 张进李亚东吕飞高秀玲崔雪红
Owner TIANJIN ENERGIES
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