Lithium ion battery composite diaphragm and preparation method and application thereof

A lithium-ion battery and composite diaphragm technology, which is applied to secondary batteries, battery pack components, circuits, etc., can solve the problems of potential safety hazards such as thermal runaway of batteries, poor liquid-holding capacity of diaphragms, and poor electrolyte affinity. Large-scale short-circuit or overheating, improving liquid retention capacity, and not easy to short-circuit

Inactive Publication Date: 2014-11-19
SHANGHAI FANNENG NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the use of polyolefin microporous membranes in battery separators mainly has the following problems: (1) polyolefins, as non-polar materials, have poor affinity with highly polar electrolytes, that is, the diaphragm has poor liquid retention capacity; (2) polyolefins Microporous membranes are mostly made by mechanical stretching, or by organic solvent extraction aft

Method used

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  • Lithium ion battery composite diaphragm and preparation method and application thereof
  • Lithium ion battery composite diaphragm and preparation method and application thereof
  • Lithium ion battery composite diaphragm and preparation method and application thereof

Examples

Experimental program
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Embodiment 1

[0039] The lithium ion battery composite separator in this embodiment includes a polyolefin microporous membrane, a polymer microsphere-based coating coated on one side of the polyolefin microporous membrane, and a coating on the other side of the polyolefin microporous membrane Inorganic ceramic-based coating. The thickness of the composite diaphragm is 27 μm, wherein the thickness of the polyolefin microporous membrane is 20 μm, the porosity is 40%, the thickness of the polymer microsphere-based coating is 4 μm, and the thickness of the inorganic ceramic-based coating is 3 μm. The structure diagram of the composite diaphragm is shown in figure 1 , See the SEM image of each coating figure 2 , image 3 , See the SEM picture of ordinary PP film Figure 4 . figure 1 Middle 1 and 3 are polymer microsphere-based coating and inorganic ceramic-based coating respectively, and 2 is polyolefin microporous membrane (polypropylene microporous membrane).

[0040] The preparation method of t...

Embodiment 2

[0050] The lithium ion battery composite separator in this embodiment includes a polyolefin microporous membrane (polypropylene microporous membrane), a polymer microsphere-based coating coated on one side of the polyolefin microporous membrane, and a polyolefin Inorganic ceramic-based coating on the other side of the microporous membrane. The thickness of the composite diaphragm is 27 μm, wherein the thickness of the polyolefin microporous membrane is 20 μm, the porosity is 40%, the thickness of the polymer microsphere-based coating is 4 μm, and the thickness of the inorganic ceramic-based coating is 3 μm.

[0051] The preparation method of the lithium ion battery composite diaphragm in this embodiment includes the following steps:

[0052] (1) Add SiO with a particle size of 0.9μm to deionized water 2 The particles were stirred with a high-speed disperser for 1 hour, then the binder PVDF was added, and the stirring was continued for 1 hour to obtain inorganic ceramic slurry, in w...

Embodiment 3

[0057] The lithium ion battery composite separator in this embodiment includes a polyolefin microporous membrane (polypropylene microporous membrane), a polymer microsphere-based coating coated on one side of the polyolefin microporous membrane, and a polyolefin Inorganic ceramic-based coating on the other side of the microporous membrane. The thickness of the composite diaphragm is 27 μm, wherein the thickness of the polyolefin microporous membrane is 20 μm, the porosity is 40%, the thickness of the polymer microsphere-based coating is 3 μm, and the thickness of the inorganic ceramic-based coating is 4 μm.

[0058] The preparation method of the lithium ion battery composite diaphragm in this embodiment includes the following steps:

[0059] (1) Add TiO with a particle size of 1.0μm to deionized water 2 The particles are stirred for 1 hour with a high-speed disperser, then the binder PVDF is added, and the stirring is continued for 1 hour to obtain inorganic ceramic slurry, in whic...

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Abstract

The invention discloses a lithium ion battery composite diaphragm and a preparation method and an application thereof, belonging to the technical field of lithium ion batteries. The composite diaphragm comprises a polyolefin microporous membrane, a polymer microsphere based coating on one side surface of the polyolefin microporous membrane, and an inorganic ceramic-based coating on the other side surface of the polyolefin microporous membrane. The lithium ion battery composite diaphragm has good air permeability, liquid retaining capability and high-temperature resistance and can remarkably improve the security and the circulation property of the battery. The melting point or softening point of the polymer microsphere-based coating in the composite diaphragm is 90-140 DEG C, and when the temperature of the battery is increased, the polymer microsphere based coating is molten or swelled within a short time, then the apertures of the polyolefin microporous membrane are blocked rapidly, the thermal turn-off effect of the diaphragm is achieved, a lithium ion conveying channel is cut off, and short circuit inside the battery is prevented; meanwhile as ceramic grains inside the inorganic ceramic-based coating have the high-temperature resistance property, the polyolefin microporous membrane is effectively prevented from shrinkage, and the situation that positive and negative films directly come into contact to cause short circuit of the battery.

Description

Technical field [0001] The invention specifically relates to a lithium ion battery composite diaphragm, and also relates to a preparation method and application of the composite diaphragm, and belongs to the technical field of lithium ion batteries. Background technique [0002] The battery separator refers to a thin layer of porous material between the positive and negative electrodes of the battery. It is a very critical part of the battery and has a direct impact on the safety and cost of the battery. It needs to have high ion permeability and good mechanical strength, and long-term stability to the chemicals and solvents used in the system such as the battery electrolyte. In the battery, the separator must completely isolate the cathode and anode electrodes, but at the same time allow the electrolyte to permeate, and it must also have lasting elasticity. [0003] At present, the traditional battery separator is a porous organic polymer film, and the typical organic separator i...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/446Y02E60/10
Inventor 白莉怀永建王海文张海峰张国军
Owner SHANGHAI FANNENG NEW MATERIAL TECH CO LTD
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