Preparation method of lithium battery composite diaphragm with multi-layer structure

A technology of composite diaphragm and multi-layer structure, which is applied in the direction of structural parts, circuits, electrical components, etc., can solve the problems of reducing battery performance, increasing lithium ion migration resistance, and low swelling, without reducing porosity and ion mobility. , Excellent ionic conductivity, and the effect of improving heat shrinkage

Inactive Publication Date: 2022-04-29
JIANGSU HORIZON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this stage, ceramic coating can effectively increase battery performance such as safety and specific capacity, but it is easy to fall off during use and has a short life; therefore, polytetrafluoroethylene is often used as a binder and added to the ceramic coating, or It is used to coat the outside of the ceramic coating to enhance the adhesion of the ceramic coating; however, polytetrafluoroethylene has a high degree of crystallinity and is granular, making it easy to de-powder in the subsequent cell preparation process after coating; at the same time It has small swelling and poor liquid absorption, which reduces the mobility of lithium ions and reduces the performance of the battery
In addition, after the coating is applied, the pore area of ​​the base film will be reduced, and the resistance to lithium ion migration will be increased, thereby reducing electron mobility and battery performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Step 1: weigh 20g CMC, place it in 400g deionized water, and dissolve it with magnetic stirring to prepare CMC aqueous solution. Add 4G silicate dispersant into 475g deionized water, stir for 30min, add 375g alumina into it, stir for 30min, add 98g CMC aqueous solution, evenly disperse the slurry system through a planetary ball mill, set the parameters of the ball mill to 400rpm / min for 1h, then add 46g polyvinyl alcohol into the above solution system, continue ball milling for 30min, and finally add 2G silicone ether wetting agent, ball milling for 30min to obtain ceramic slurry. It is coated to 9 on one side by micro intaglio coating μ M of PE base film surface to obtain 3 μ M ceramic layer.

[0031] Step 2: dissolve 50g poss and 75g PVDF HFP in 300gn-n dimethylformamide solution, stir for 30min, add 25g MMA and 25g benzophenone initiator, stir for 30min until it is completely dissolved, add 35g polyethylene glycol and stir for 10min until it is dissolved to obtain PMMA...

Embodiment 2

[0033] Step 1: weigh 20g CMC, place it in 400g deionized water, and dissolve it with magnetic stirring to prepare CMC aqueous solution. Add 5g carboxylate dispersant into 492g deionized water, stir for 30min, add 320G alumina into it, stir for 30min, add 128G CMC aqueous solution, evenly disperse the slurry system through a planetary ball mill, set the parameters of the ball mill to 400rpm / min for 1h, then add 52g polyvinyl alcohol into the above solution system, continue ball milling for 30min, finally add 3G silica ether wetting agent and ball milling for 30min to obtain ceramic slurry; It is coated to 7 on one side by microgravure coating μ M of PE base film surface to obtain 2 μ M ceramic layer.

[0034] Step 2: dissolve 25g poss and 100g PVDF-HFP in 275gn-n dimethylformamide solution, stir for 30min, add 50g MMA and 25g benzophenone initiator, stir for 30min until it is completely dissolved, add 25g polyethylene glycol and stir for 10min until it is dissolved to obtain PMMA...

Embodiment 3

[0036] Step 1: weigh 20g CMC, place it in 400g deionized water, and dissolve it with magnetic stirring to prepare CMC aqueous solution. Add 4G silicate dispersant into 475g deionized water, stir for 30min, add 375g alumina into it, stir for 30min, add 98g CMC aqueous solution, evenly disperse the slurry system through a planetary ball mill, set the parameters of the ball mill to 400rpm / min for 1h, then add 46g polyvinyl alcohol into the above solution system, continue ball milling for 30min, and finally add 2G silicone ether wetting agent, ball milling for 30min to obtain ceramic slurry. It is coated to 9 on one side by micro intaglio coating μ M of PE base film surface to obtain 3 μ M ceramic layer.

[0037]Step 2: (1) add cage polysilsesquioxane and chlorosulfonic acid with a molar ratio of 1:6 to the reactor, stir at 0 ℃ for 24 hours, distill to remove the solvent, wash with tetrahydrofuran and dry to obtain polysilsesquioxane a; (2) Dissolve 50g possa and 75g PVDF-HFP in 300...

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PUM

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Abstract

The invention discloses a preparation method of a lithium battery composite diaphragm with a multilayer structure. Comprising the following steps: step 1, coating the surface of a base membrane with ceramic slurry, and drying to obtain a ceramic layer; step 2: (1) dissolving polyvinylidene fluoride-hexafluoropropylene and polyhedral oligomeric silsesquioxane in a solvent; adding methyl methacrylate and an initiator, and dissolving; adding a pore-foaming agent, and uniformly stirring; the PMMA/PVDF-HFP slurry is obtained; (2) coating the PMMA/PVDF-HFP slurry on the ceramic layer, and carrying out ultraviolet curing and drying on the PMMA/PVDF-HFP slurry; washing to remove the pore-foaming agent, and drying to obtain a PMMA/PVDF-HFP layer; therefore, the lithium battery composite diaphragm with the sandwich structure is prepared. The lithium battery composite diaphragm has the beneficial effects that the ceramic coating and the PMMA/PVDF-HFP layer are respectively coated on the base membrane and compounded to prepare the lithium battery composite diaphragm with a sandwich structure, and the two layers are remarkably matched, so that the lithium battery composite diaphragm has excellent high temperature resistance, wettability and safety and excellent ionic conductivity.

Description

technical field [0001] The invention relates to the technical field of multi-layer battery diaphragm, in particular to a preparation method of lithium composite diaphragm with multi-layer structure. Background technology [0002] In recent years, the popularization of automobile industry and the shortage of traditional automobile resources have accelerated the development of automobile industry; In order to implement the concept of national green development, improve the living environment and alleviate the shortage of oil resources, the electric vehicle industry has been vigorously developed and widely supported. [0003] At present, lithium-ion battery is the most popular power source of electric vehicles; It consists of three main parts: positive electrode, negative electrode and diaphragm carrying electrolyte. Among them, as one of the important components of lithium-ion battery, diaphragm is mainly used to prevent internal short circuit of battery, carry electrolyte and prov...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/403H01M50/457H01M50/451H01M50/434H01M50/489H01M50/491H01M50/497H01M10/0525
CPCH01M50/403H01M50/457H01M50/451H01M50/434H01M50/489H01M50/491H01M50/497H01M10/0525
Inventor 李梦佳张立斌沈亚定贡晶晶
Owner JIANGSU HORIZON NEW ENERGY TECH CO LTD
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