Composite separator for lithium ion battery

A lithium-ion battery and separator technology, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of difficulty in replenishing active lithium loss, poor tensile and puncture resistance of separators, and reduce heat Loss of control, alleviation of swelling, effect of increasing discharge capacity

Active Publication Date: 2021-06-22
XUCHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems and defects of traditional lithium-ion battery separators such as poor stretch resistance and puncture resistance, and difficulty in replenishing the loss of active lithium, the present invention provides a lithium-ion battery that can replenish lithium ions and improve the safety factor, discharge capacity and cycle life of lithium-ion batteries. Composite isolation film with equal performance

Method used

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  • Composite separator for lithium ion battery
  • Composite separator for lithium ion battery
  • Composite separator for lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Embodiment 1: a kind of lithium ion battery composite separator described in this embodiment, comprises base film 1, is coated with gel coating 3 on the surface of base film 1 towards negative electrode side, between base film 1 and gel A buffer ceramic coating 2 is coated between the coatings 3, and a heat-sensitive semiconductor lithium-supplementing coating 4 is coated on the surface of the base film 1 facing the positive electrode; the composite separator is prepared by the following steps:

[0021] Step 1. Preparation of Buffer Ceramic Coating

[0022] Add 32kg of ferric phosphate with a D50 of 1.5μm, 4.8kg of polyurethane binder, 0.4kg of sulfonic acid sodium salt dispersant and 42.8kg of deionized water into a stirring tank with a capacity of 100L, and stir for 5 hours at a speed of 1500rpm , to obtain a buffer ceramic coating slurry with a viscosity of 200mPa·s. Using the gravure printing coating process, the slurry was coated on the surface of one side of the ...

Embodiment 2

[0027] Embodiment 2: a kind of lithium ion battery composite separator described in this embodiment, comprises base film 1, is coated with gel coating 3 on the surface of base film 1 towards the negative electrode side, between base film 1 and gel A buffer ceramic coating 2 is coated between the coatings 3, and a heat-sensitive semiconductor lithium-supplementing coating 4 is coated on the surface of the base film 1 facing the positive electrode; the composite separator is prepared by the following steps:

[0028] Step 1. Preparation of Buffer Ceramic Coating

[0029] 12kg of iron oxide with D50 of 0.5μm, 12kg of iron phosphate with D50 of 0.5μm, 0.8kg of polyurethane adhesive, 0.8kg of polyacrylic adhesive, 0.08kg of carboxylic acid sodium salt dispersant and 54.32kg of deionized Water was added to a stirring tank with a capacity of 100 L, and stirred at a speed of 2200 rpm for 1 h to obtain a buffer ceramic coating slurry with a viscosity of 50 mPa·s. Using the gravure prin...

Embodiment 3

[0034] Embodiment 3: A kind of composite separator of lithium ion battery described in this embodiment, comprises base film 1, is coated with gel coating 3 on the surface of base film 1 towards negative electrode side, between base film 1 and gel A buffer ceramic coating 2 is coated between the coatings 3, and a heat-sensitive semiconductor lithium-supplementing coating 4 is coated on the surface of the base film 1 facing the positive electrode; the composite separator is prepared by the following steps:

[0035] Step 1. Preparation of Buffer Ceramic Coating

[0036] 16kg of manganese dioxide with D50 of 1 μm, 12kg of manganese trioxide with D50 of 1 μm, 2.4kg of polyurethane adhesive, 0.8kg of polyimide adhesive, 0.08kg of sulfonic acid sodium salt dispersant, 0.24 kg of carboxylic acid sodium salt dispersant and 48.48 kg of deionized water were added to a stirring tank with a capacity of 100 L, and stirred at a speed of 1800 rpm for 3 h to obtain a buffer ceramic coating slu...

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Abstract

The invention provides a composite separator with the functions of safety, liquid retention and lithium supplementation. The composite separator is coated with a buffer ceramic coating with a safety protection function on the surface of the PE base film facing the negative electrode, and The surface of the buffer ceramic coating is then coated with a gel coating with a liquid retention function, while the surface of the PE base film facing the positive side is coated with a mixed coating of a semiconductor with a thermistor function and an inorganic material with a lithium supplement function. The composite separator provided by the present invention can not only alleviate the battery deformation caused by electrode expansion, reduce the risk of internal short circuit caused by thermal runaway and burrs, but also supplement the loss of lithium ions in the formation process and improve the discharge capacity of lithium-ion batteries .

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a lithium-ion battery composite separator with properties such as safety, liquid retention and lithium supplementation. Background technique [0002] The safety problem of lithium-ion batteries is essentially an internal short circuit between the positive and negative electrodes caused by the damage of the separator. The traditional lithium-ion battery separator is made of polyethylene (PE) or polypropylene (PP), which has poor tensile and puncture resistance, which makes lithium-ion batteries have high safety hazards. In particular, the 5-12 μm ultra-thin PE separator, which has gradually become the mainstream in the market due to the pursuit of high specific energy, poses a more serious challenge to the safety of lithium-ion batteries. In response to this problem, the industry basically adopts the coating of alumina ceramic powder on the PE or PP isolation film t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M50/434H01M50/426H01M50/403H01M10/0525H01M50/423H01M50/457
CPCH01M10/0525H01M50/403H01M50/449Y02E60/10
Inventor 董振伟李皓熊海岩高远浩
Owner XUCHANG UNIV
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