High-safety composite diaphragm and preparation method thereof

A composite diaphragm and a safe technology, applied in the field of high-safety composite diaphragm and its preparation, can solve the problems such as the inability to effectively suppress the chain reaction of internal short circuit, and achieve the effects of avoiding battery thermal runaway, inhibiting heat accumulation, and improving safety.

Pending Publication Date: 2020-09-22
TIANJIN LISHEN BATTERY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for high energy density systems, the "blocking" strategy cannot effectively supp

Method used

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  • High-safety composite diaphragm and preparation method thereof
  • High-safety composite diaphragm and preparation method thereof
  • High-safety composite diaphragm and preparation method thereof

Examples

Experimental program
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Example Embodiment

[0087] In order to prepare the high-safety composite diaphragm provided by the present invention, see figure 1 As shown, the present invention also provides a method for preparing a high-safety composite diaphragm, which includes the following steps:

[0088] In the first step, the high thermal conductivity material, the conductive agent, the lithium ion conductive material, the binder, the dispersant and the solvent are mixed uniformly to prepare the functional material layer slurry to be coated;

[0089] The second step is to apply the micro-gravure coating method to apply the functional material layer slurry to the commercial diaphragm on one or both sides to obtain a composite diaphragm;

[0090] The third step is to perform drying, heat setting and winding operations on the coated composite diaphragm.

[0091] It should be noted that the micro-gravure coating method is an existing common slurry coating method, and will not be repeated here.

[0092] It should be noted that, based o...

Example Embodiment

[0114] Example 1.

[0115] The method for preparing a high-safety composite diaphragm provided by the present invention includes the following steps:

[0116] In the first step, a polyethylene (PE) membrane with a thickness of 12 microns is selected as the coating base film. The coating slurry is prepared using inorganic nano thermal conductive material (hexagonal boron nitride), lithium lanthanum zirconate LLZO (as a lithium ion conductive material), carbon nanotubes CNT, binder PAN, dispersant PVP, solvent NMP, etc. The weight percentage distribution of the solid raw material of the coating slurry is: 40% of inorganic nano thermal conductive material, 35% of LLZO, 5% of CNT, 15% of binder, and 5% of dispersant. The solvent of the slurry is NMP, and the solid content of the slurry is 10%. Use a centrifugal disperser to thoroughly mix and disperse the above mixture to obtain a mixed slurry;

[0117] The second step is to apply the micro-gravure coating method to single-sided coati...

Example Embodiment

[0119] Example 2.

[0120] The method for preparing a high-safety composite diaphragm provided by the present invention includes the following steps:

[0121] In the first step, a polypropylene (PP) membrane with a thickness of 16 microns is selected as the coating base film. Use inorganic nano thermal conductive material (mixed material of hexagonal boron nitride and aluminum oxide), lithium titanium aluminum phosphate LATP (as lithium ion conductive material), graphene, binder PAN, dispersant PVP, solvent NMP, etc. to prepare coating slurry material. The solid raw material weight percentage distribution of the coating slurry is as follows: inorganic nano thermal conductive material is 50%, LATP is 30%, graphene is 5%, binder is 13%, and dispersant is 2%. The solvent of the slurry is NMP, and the solid content of the slurry is 15%. Use a centrifugal disperser to thoroughly mix and disperse the above mixture to obtain a mixed slurry;

[0122] The second step is to use the micro-g...

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Abstract

The invention discloses a high-safety composite diaphragm. The diaphragm comprises a commercial diaphragm, wherein the single-side or double-side surface of the commercial diaphragm is coated with atleast one functional material layer; the commercial diaphragm is used for bearing and fixing the functional material layer; the functional material layer comprises a high-thermal-conductivity material, a conductive agent, a lithium ion conductive material, a binder and a dispersing agent. In addition, the invention also discloses a preparation method of the high-safety composite diaphragm. The method comprises the following steps: 1, uniformly mixing the high-thermal-conductivity material, the conductive agent, the lithium ion conductive material, the binder, the dispersing agent and the solvent to obtain functional material layer slurry; 2, performing single-sided or double-sided coating on the commercial diaphragm by using the functional material layer slurry in a micro-gravure coating mode to obtain a composite diaphragm; 3, sequentially carrying out drying treatment, heat setting and rolling operation on the composite diaphragm. Starting from two aspects of heat generation and heatconduction, heat accumulation caused by short circuit in the battery can be effectively inhibited, and thermal runaway is avoided.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a high-safety composite diaphragm and a preparation method thereof. Background technique [0002] During the use of lithium-ion battery cells, modules or systems, internal short circuits will occur under overcurrent, overcharge, internal lithium dendrites, extrusion, mechanical shock, puncture or other abuses. When the accumulated Joule heat cannot be quickly diffused and discharged, an exothermic chain reaction will occur, triggering an exothermic reaction of large-area negative electrodes, positive electrodes, electrolytes, separators and other materials, eventually leading to thermal runaway of lithium-ion batteries. [0003] At present, diaphragm regulation is a common method to suppress the internal short circuit of the battery. The polymer diaphragm is used as the base film, and the surface is coated with granular materials with high mechanical strength such a...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M2/14H01M10/613H01M10/653H01M10/654
CPCH01M10/613H01M10/653H01M10/654Y02E60/10
Inventor 周江孟繁慧李慧芳
Owner TIANJIN LISHEN BATTERY
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