Ceramic diaphragm for lithium ion battery and preparation method of ceramic diaphragm

A lithium-ion battery, ceramic separator technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problems of limited liquid absorption capacity, weak binding force between ceramic particles and binders, and easy to fall off powder. Enhanced stability, enhanced binding force, and the effect of preventing powder drop

Inactive Publication Date: 2016-04-20
TIANNENG SAFT ENERGY JOINT CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In the prior art, ordinary ceramic powder is usually used for coating, and the specific surface area is only a dozen m 2 / g to tens of m 2 / g, the liquid absorption capacity is still limited, and the bonding force between the ceramic particles and the binder is weak, and powder dropping is prone to occur.

Method used

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Examples

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Effect test

preparation example Construction

[0038] The preparation method of porous aluminum oxide in the present invention is as follows:

[0039] 18% aluminum nitrate solution and 8% ammonium bicarbonate solution were respectively prepared by using 1 g / L CTAB (cetyltrimethylammonium bromide) aqueous solution. Slowly add the ammonium bicarbonate solution dropwise to the aluminum nitrate solution, stir quickly to form a sol, and after standing for a period of time, vacuum-dry the sol to obtain a white powder, which is calcined at 550°C for 2 hours to obtain porous aluminum oxide . The obtained porous aluminum oxide has a particle size of about 100nm and a specific surface area of ​​432m 2 / g.

[0040] The preparation method of porous silica in the present invention is as follows:

[0041] Add 2g CTAB, 10g 32% ammonia water, and 50g absolute ethanol to 50mL deionized water in turn, stir and mix evenly, add 3.6g tetraethyl orthosilicate, stir for 2 hours, filter the white precipitate and wash it with deionized water fo...

Embodiment 1

[0043] 1. The particle size of 1g is about 100nm and the specific surface area is 432m 2 / g of porous aluminum oxide powder, 0.3g of polyvinylidene fluoride (PVDF) and 7.5g of N-methylpyrrolidone (NMP) were uniformly mixed to obtain a ceramic coating slurry.

[0044] 2. Evenly coat the ceramic coating slurry on one side of a polyethylene (PE) diaphragm with a thickness of 20 μm through a coating machine, and dry it in vacuum (vacuum degree 0.01 MPa) at 80 ° C to form a coating with a thickness of 3 μm The ceramic diaphragm A1.

Embodiment 2

[0046] 1. The particle size of 1.5g is about 200nm and the specific surface area is 576m 2 / g of porous silica powder, 0.1 g of sodium carboxymethylcellulose (CMC), 0.1 g of styrene-butadiene rubber (SBR) and 8 g of deionized water were uniformly mixed to obtain a ceramic coating slurry.

[0047] 2. Apply the ceramic coating slurry evenly on one side of the polypropylene (PP) diaphragm with a thickness of 20 μm through a coating machine, and dry it in vacuum (vacuum degree 0.01 MPa) at 80°C to form a coating with a thickness of 4 μm The ceramic diaphragm A2.

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PUM

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Abstract

The invention discloses a ceramic diaphragm for a lithium ion battery. The ceramic diaphragm comprises a diaphragm base material and a ceramic coating on the surface of the diaphragm base material, wherein ceramic particles having a porous structure and a high specific surface area are selected for the ceramic coating. A preparation method includes the following steps of firstly, evenly mixing ceramic particles, binder and solvent to obtain coating slurry; secondly, evenly coating the surface of the diaphragm base material with the coating slurry, and conducting drying to form the ceramic diaphragm. Quite strong binding force exists between the porous ceramic powder and the binder, and the powder falling phenomenon is effectively avoided; meanwhile, the ceramic diaphragm has high electrolyte wettability and quite strong liquid absorption capacity, the cycle life and rate capability of the lithium ion battery are increased, and excellent electrochemical performance is achieved; in addition, under the same thickness, the mass of the porous ceramic coating is far lower than that of an ordinary ceramic coating, and the energy density of the battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a ceramic separator for lithium ion batteries and a preparation method thereof. Background technique [0002] The main function of the separator in a lithium-ion battery is to isolate the positive and negative electrodes and prevent electrons from passing through, while allowing lithium ions to pass through, thereby completing the rapid transmission of lithium ions between the positive and negative electrodes during charge and discharge. The performance of the separator directly affects the battery internal resistance, discharge capacity, cycle life and battery safety performance. Polyolefin materials have excellent mechanical properties, chemical stability and relatively cheap characteristics. They have been widely used in the early stage of lithium battery research and development, and have become the mainstream direction of lithium battery separators,...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M2/14H01M50/403H01M50/434H01M50/491
CPCH01M50/431H01M50/403H01M50/449Y02E60/10
Inventor 余心亮孙伟李文何文祥李靖赵冲冲
Owner TIANNENG SAFT ENERGY JOINT CO
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