Composite lithium ion battery separator and preparation method therefor

A technology of ion batteries and lithium composites, applied in the direction of secondary batteries, battery components, circuits, etc., can solve the problems that cannot be used alone, low strength of battery diaphragm, poor heat resistance, etc., and achieve easy market promotion and application, improve The effect of charging and discharging rate and improving the mechanical strength

Inactive Publication Date: 2016-09-07
FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most commonly used separators for lithium-ion batteries are still polyolefin separators, mainly polyethylene (PE) separators and polypropylene (PP) separators; polyolefin separators have many advantages, but they have low melting point and poor heat resistance, which lead to Disadvantages such as large thermal shrinkage rate and low membrane rupture temperature
[0004] With the gradual development of lithium-ion batteries to high energy density, high power density and high current charge and discharge, battery separators with better temperature resistance and higher membrane rupture temperature are required. Polyolefin separators can no longer meet the needs of future battery development.
In addition, because the polyolefin separator itself is non-polar, it cannot maintain good wettability with the polar electrolyte, so that the lithium ions dissolved in the electrolyte cannot shuttle between the positive and negative electrodes in a timely and smooth manner, resulting in the internal resistance of the battery. Increase, affecting the energy density of the battery and the full electrical performance of the large current
[0005] In view of the defects of polyolefin diaphragms, there have been three-layer composite diaphragms including PP/PE/PP, inorganic particles and heat-resistant organic coatings coated with polyolefin diaphragms to improve heat resistance, and non-woven fabrics modified with non-woven fabrics or inorganic particles. Woven separators, but these separators still have defects that cannot be ignored, such as PP/PE/PP still have poor

Method used

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  • Composite lithium ion battery separator and preparation method therefor
  • Composite lithium ion battery separator and preparation method therefor
  • Composite lithium ion battery separator and preparation method therefor

Examples

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preparation example Construction

[0035] A preparation method of a composite lithium-ion battery diaphragm, the preparation method comprising the following steps:

[0036] 1) Prepare polymethyl methacrylate polymer mixture: dissolve polymer resin in solvent, then add crosslinking agent, adhesive, defoamer and leveling agent in sequence, stir well, add initiator and continue stirring Uniformly, obtain polymethyl methacrylate polymer mixed solution;

[0037] 2) Preparation of the composite lithium-ion battery separator: immerse the non-woven fabric in the step 1) polymethyl methacrylate polymer mixture, then uniformly extract the non-woven fabric, and obtain the composite lithium-ion battery separator after drying.

[0038] As a further solution, in step 2) of the present invention, the non-woven fabric is soaked in the polymethyl methacrylate polymer mixture for 1s-600s, and then dried at 25-100°C for 0.5h-3h.

Embodiment 1

[0041] A composite lithium-ion battery diaphragm prepared by the following method:

[0042] 1) Weigh 628.5 parts of acetone and add 100 parts of PMMA pellets while stirring. After completely dissolving, add 52.37 parts of water and 52.37 parts of isopropanol. After stirring for 30 minutes, add 20 parts of TMPTA, 8.38 parts of adhesive, 8.38 parts 1 part of defoamer, 8.38 parts of leveling agent, after stirring for 30 minutes, add 1.0 part of BPO, and continue stirring for 10 minutes;

[0043] 2) Immerse the PET non-woven fabric in the above solution for 1 min, extract the PET non-woven fabric at a uniform speed, and then dry it with air at 70° C. for 2 hours to obtain a composite lithium-ion battery separator.

[0044] The composite lithium-ion battery diaphragm obtained in embodiment 1 is scanned and photographed with a Hitachi company model S4800 scanning electron microscope, and the photographed results can be found in figure 1 and figure 2 ,in figure 1 It is a 5000 tim...

Embodiment 2

[0046] A composite lithium-ion battery diaphragm prepared by the following method:

[0047] 1) Weigh 628.5 parts of tetrahydrofuran, and while stirring, add 90 parts of PMMA pellets and 10 parts of PVDF-HFP. After completely dissolving, add 52.37 parts of water and 52.37 parts of n-butanol. After stirring for 30 minutes, add 20 parts of TAIC, 8.38 part of adhesive, 8.38 part of defoamer, 8.38 part of leveling agent, after stirring for 30 minutes, add 0.678 part of AIBN, and continue stirring for 10 minutes;

[0048] 2) Immerse the PET non-woven fabric in the above solution for 1 min, extract the cellulose non-woven fabric at a uniform speed, and then dry it by air at 70°C for 2 hours, and then dry it in a vacuum oven at 70°C for 1 hour to obtain a composite lithium-ion battery separator.

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Abstract

The invention discloses a composite lithium ion battery separator and a preparation method therefor. The composite lithium ion battery separator comprises non-woven fabric cloth used as the framework, and a composite film which is formed by a polymethyl methacrylate polymer mixed liquid on the non-woven fabric and equipped with a three-dimensional cross-linking network. The composite lithium ion battery separator adopts the non-woven fabric framework and the polymer-repaired composite structure, so that the power performance of the lithium ion battery is improved, and the safety performance of the lithium ion battery is enhanced; according to the preparation method for the composite lithium ion battery separator, the PMMA is taken as the polymer for dip-coating; a proper amount of cross-linking agent is added to the PMMA solution to trigger polymerization under a proper condition so as to form the three-dimensional cross-linking network, so that a certain framework effect is performed in the PMMA polymer, which is similar to the effect of reinforcing steel bars in reinforced concrete; and therefore, the mechanical strength of the separator is greatly improved, and the influences on the air permeability of the separator, the wettability of the electrolyte, and the like are reduced as well.

Description

technical field [0001] The invention relates to the technical field of battery diaphragm manufacturing, in particular to a composite lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] Lithium-ion battery is a rechargeable battery, it mainly relies on lithium ions to move between positive and negative electrodes to work. During the charging and discharging process, Li + Intercalation and deintercalation back and forth between two electrodes: when charged, Li + It is deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. Batteries generally use materials containing lithium elements as electrodes, which are representatives of modern high-performance batteries. [0003] Today, the society has higher and higher requirements for lithium-ion batteries with high energy density and high power den...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/414H01M50/44H01M50/491
CPCH01M10/0525H01M50/411H01M50/44H01M50/403Y02E60/10
Inventor 王晓斌王松钊蔡朝辉
Owner FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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