Preparation method of modified polyethylene diaphragm for lithium ion battery

A technology of polyethylene and diaphragm, which is applied in the direction of battery components, circuits, electrical components, etc., can solve the problems affecting the battery charge and discharge performance, the complexity of the preparation process of the diaphragm, and the impact on the porosity of the diaphragm, so as to promote interface bonding and molecular structure. Stabilizes and improves adhesive properties

Active Publication Date: 2013-03-27
CHINA HAISUM ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The published patent CN 101434708B uses water-based polymers to modify microporous polyolefin diaphragms. This technology synthesizes a polymer colloid emulsion with relatively complex components, and then coats polyolefin diaphragms. The thermal shrinkage resistance of the diaphragms is greatly improved. , but due to surface tension and other reasons, it is difficult for the coating of the water-based system to spread evenly on the surface of the polymer substrate, and it is easy to form coating defects, which will affect the charging and discharging performance of the battery
Patent CN 1312789C uses Celgard 2400 as the substrate, nano-SiO 2 , polyoxyethylene, and acetonitrile as a coating to prepare a composite lithium battery separator, but the preparation process of the separator is relatively complicated, and the nanoparticles contained in the surface coating may affect the porosity of the separator

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042]1. Synthesis of polyurethane adhesive

[0043] 1. Prepare the main agent and curing agent in the polyurethane adhesive

[0044] (1) Main agent

[0045] Formula (by weight percentage):

[0046] Polycarbonate diol (PCDL) 30%;

[0047] 1,4-cyclohexane diisocyanate (CHDI) 5.5%;

[0048] Hydroxy silicone oil (hydroxyl-terminated polydimethylsiloxane) 3%;

[0049] N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane 1.45%;

[0050] Dibutyltin dilaurate 0.05%;

[0051] Acetone 60%.

[0052] Preparation steps: Add polycarbonate diol in proportion to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and vacuum dehydrate at 120°C for 2 hours; adjust the temperature to 80°C, and add hydroxyl silicone oil, N- β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 1,4-cyclohexane diisocyanate, acetone solvent and dibutyltin dilaurate catalyst were reacted for 4 hours to obtain the main agent.

[0053] (2) curing agent

[0054] Formula (by weight percentage...

Embodiment 2

[0064] 1. Synthesis of polyurethane adhesive

[0065] 1. Prepare the main agent and curing agent in the polyurethane adhesive

[0066] (1) main ingredient formula (by weight percentage):

[0067] Polycarbonate diol (PCDL) 25%;

[0068] 1,4-cyclohexane diisocyanate (CHDI) 2.5%;

[0069] Hydroxy silicone oil (hydroxyl-terminated polydimethylsiloxane) 1.5%;

[0070] N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane 0.98%;

[0071] Dibutyltin dilaurate 0.02%;

[0072] Acetone 70%.

[0073] (2) Curing agent formula (by weight percentage):

[0074] 1,4-cyclohexane diisocyanate (CHDI) 40%;

[0075] Trimethylolpropane (TMP) 10%;

[0076] Ethyl acetate 50%.

[0077] The preparation method of main agent and curing agent is the same as embodiment 1. Mix the prepared main agent and curing agent uniformly at a weight ratio of 8.5:1, and stir at 80°C for 2 hours to prepare polyurethane adhesive PU-02.

[0078] 2. Preparation of modified polyethylene diaphragm

[0079] In the first ...

Embodiment 3

[0082] 1. Synthesis of polyurethane adhesive

[0083] 1. Prepare the main agent and curing agent in the polyurethane adhesive

[0084] (1) main ingredient formula (by weight percentage):

[0085] Polycarbonate diol (PCDL) 28.5%;

[0086] 1,4-cyclohexane diisocyanate (CHDI) 3.5%;

[0087] Hydroxy silicone oil (hydroxyl-terminated polydimethylsiloxane) 1.97%;

[0088] N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane 1%;

[0089] Dibutyltin dilaurate 0.03%;

[0090] Acetone 65%.

[0091] (2) Curing agent formula (by weight percentage):

[0092] 1,4-cyclohexane diisocyanate (CHDI) 45%;

[0093] Trimethylolpropane (TMP) 15%;

[0094] Ethyl acetate 40%.

[0095] The preparation method of main agent and curing agent is the same as embodiment 1. The prepared main agent and curing agent were uniformly mixed in a weight ratio of 9:1, and stirred at 80° C. for 2 hours to obtain polyurethane adhesive PU-03.

[0096] 2. Preparation of modified polyethylene diaphragm

[0097] In t...

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Abstract

The invention discloses a preparation method of a modified polyethylene diaphragm for a lithium ion battery. The preparation method of the modified polyethylene diaphragm is characterized in that a high-temperature resistance coating is uniformly coated on the two surfaces of the polyethylene diaphragm, and the modified polyethylene diaphragm is formed after drying; and the high-temperature resistance coating comprises inorganic particulate matters, a polyurethane adhesive, a dispersing agent and an ethanol solution. The high-temperature resistance coating adopted in the invention has low surface tension and is more environment-friendly by taking an ethanol solution as a solvent; dispersed phases in the high-temperature resistance coating are coated on the two surfaces of the polyethylene diaphragm to form a high-temperature resistance Al2O3 coating which can stop a positive electrode and a negative electrode from directly contacting when a base material melts, slows down the release of heat energy and improves the safety performance of the battery; and the polyurethane adhesive synthesized in the invention increases an interface bonding force between Al2O3 particles and the base material of the polyethylene diaphragm, enhances the adhesion between the Al2O3 particles and the base material, and simultaneously increases the imbibition capacity and heat resistance performance of the modified polyethylene diaphragm.

Description

technical field [0001] The invention relates to a modification technology of polyethylene (PE) separators for lithium ion batteries, belonging to the technical field of lithium ion batteries. Background technique [0002] At present, lithium-ion battery separator materials are mainly polyolefin separators such as single-layer polypropylene (PP) microporous membranes, single-layer polyethylene (PE) microporous membranes, and three-layer PP / PE / PP composite membranes. Mainly dry stretching porogenic method and wet phase separation method. The melting point of the polyolefin separator is low, the closed cell temperature of the PE separator is 130-140°C, and that of the PP separator is 150-166°C. The separator is easy to shrink when heated, and the direct contact of the positive and negative electrodes will cause a short circuit of the lithium-ion battery, and it is easy to break at high temperature. film, causing disintegration or explosion of the lithium-ion battery. [0003]...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J7/04C08L23/06C09D175/04C09D7/12C08G18/75C08G18/66C08G18/65C08G18/61C08G18/44C08G18/32H01M2/16
CPCY02E60/12Y02E60/10
Inventor 贺磊吴立群
Owner CHINA HAISUM ENG
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