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Composite lithium supplementing diaphragm and secondary battery thereof

A separator and lithium replenishment technology, applied in secondary batteries, secondary battery repair/maintenance, battery pack components, etc., can solve the problems of active lithium deactivation, no protective layer, safety risks, etc.

Active Publication Date: 2021-07-06
TIANJIN ENERGIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the surface of the metal lithium layer does not contain a protective layer, and the lithium layer will react with the environment, which may lead to the deactivation of a part of the active lithium and even pose a safety risk.

Method used

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  • Composite lithium supplementing diaphragm and secondary battery thereof
  • Composite lithium supplementing diaphragm and secondary battery thereof
  • Composite lithium supplementing diaphragm and secondary battery thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Such as figure 1 As shown, the composite lithium-supplementing diaphragm porous base membrane (PP film, 9 μm); a lithium-containing layer 1 is provided on one side of the base membrane, and the lithium-containing layer 1 is composed of a lithium-containing layer 11 and a lithium-containing layer 12, and is close to the base membrane. The mass proportion of the lithium source in the lithium-containing layer 11 is 10%, and the thickness is 2 μm; the mass proportion of the lithium source in the lithium-containing layer 12 away from the porous base film is 50%, and the thickness is 2 μm; An inorganic ceramic protective layer is provided with a thickness of 2 μm and a porosity of 30%.

[0029] 1) The preparation method of lithium-replenishing composite diaphragm, comprises the following steps:

[0030] a) Preparation and coating of lithium-containing layer 11 slurry

[0031] The lithium powder SLMP, styrene-butadiene rubber, silicon dioxide and NMP are mixed according to t...

Embodiment 2

[0038] Such as figure 1 As shown, the composite lithium-supplementing diaphragm porous base membrane (PP film, 9 μm); a lithium-containing layer 1 is provided on one side of the base membrane, and the lithium-containing layer 1 is composed of a lithium-containing layer 11 and a lithium-containing layer 12, and is close to the base membrane. The mass proportion of the lithium source in the lithium-containing layer 11 is 20%, and the thickness is 2 μm; the mass proportion of the lithium source in the lithium-containing layer 12 away from the porous base film is 60%, and the thickness is 3 μm; An inorganic ceramic protective layer is provided with a thickness of 1 μm and a porosity of 15%.

[0039] 1) The preparation method of lithium-replenishing composite diaphragm, comprises the following steps:

[0040] a) Preparation and coating of lithium-containing layer 11 slurry

[0041] The lithium supplement material Li 2 O, PVDF, Al 2 o 3 Mix with NMP according to the ratio of 2:...

Embodiment 3

[0048] Such as figure 1 As shown, the porous base membrane (PE film, 12 μm) of the composite lithium-supplementing separator; a lithium-containing layer 1 is provided on one side of the base membrane, and the lithium-containing layer 1 is composed of a lithium-containing layer 11 and a lithium-containing layer 12, and is close to the base membrane. The mass proportion of the lithium source in the lithium-containing layer 11 is 15%, and the thickness is 2 μm. The mass proportion of the lithium source in the lithium-containing layer 12 away from the porous base film is 45%, and the thickness is 2 μm; An inorganic ceramic protective layer is provided with a thickness of 1 μm and a porosity of 25%.

[0049] 1) The preparation method of lithium-replenishing composite diaphragm, comprises the following steps:

[0050] a) Preparation and coating of lithium-containing layer 11 slurry

[0051] The lithium powder SLMP, styrene-butadiene rubber, silicon dioxide and NMP are mixed accord...

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Abstract

The invention provides a composite lithium supplement diaphragm and a secondary battery thereof, the composite lithium supplement diaphragm comprises a porous base membrane, a lithium-containing layer is arranged on one side of the porous base membrane, the lithium-containing layer comprises lithium sources, inorganic ceramic powder and a binder, the lithium sources are in gradient distribution in the thickness direction of the lithium-containing layer, and the mass ratio of the lithium source close to one side of the surface of the porous base membrane is relatively low. According to the invention, the irreversible active lithium loss in the first charging process can be effectively compensated without additionally supplementing lithium on the surface of the positive pole piece or the negative pole piece, so that the energy density and the cycle life of the lithium ion secondary battery can be remarkably improved. The lithium source in the lithium-containing layer of the composite diaphragm is in gradient distribution, and the active lithium content is relatively low on one side close to the surface of the base membrane, so that the contact area of metal lithium powder or a lithium-containing compound and the like with the base membrane can be effectively reduced, the risk that micropores of the base membrane are possibly blocked is reduced, and the performance of a battery cell is further improved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a composite lithium-supplementing diaphragm and a secondary battery thereof. Background technique [0002] Due to the advantages of high energy density, long cycle life, environmental protection and no memory effect, lithium-ion secondary batteries have gradually developed into one of the most promising secondary batteries and have been used in various fields, such as mobile phones, notebooks, digital Cameras, portable devices, electric vehicles, energy storage devices. [0003] For lithium secondary batteries, during the first charging process, an SEI (solid electrolyte interphase) film will be formed on the surface of the negative electrode. This process will consume a large amount of lithium ions extracted from the positive electrode material, resulting in an irreversible loss of positive electrode capacity. In addition, during the long-term cycle an...

Claims

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Application Information

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IPC IPC(8): H01M50/446H01M50/449H01M50/451H01M50/491H01M10/0525H01M10/42
CPCH01M10/0525H01M10/4235Y02P70/50Y02E60/10H01M50/451H01M50/446H01M50/417H01M50/42H01M50/423H01M50/426H01M50/414H01M50/434H01M50/431H01M4/0447
Inventor 邓海福李兴旺王俊姿李文文
Owner TIANJIN ENERGIES
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