Lithium-ion battery diaphragm, preparation method thereof and lithium-ion battery

A technology for lithium-ion batteries and diaphragms, which is applied in secondary batteries, battery pack parts, separators/films/diaphragms/spacers, etc., and can solve complex processing techniques, high process costs, and poor heat resistance of product films, etc. question

Active Publication Date: 2017-06-30
CHNA ENERGY INVESTMENT CORP LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to solve the problems of complex processing technology, high process cost and poor heat resistance of the product film in the prior art, and provide a lithium-ion battery separator, a preparation method and a lithium-ion battery separator.

Method used

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  • Lithium-ion battery diaphragm, preparation method thereof and lithium-ion battery
  • Lithium-ion battery diaphragm, preparation method thereof and lithium-ion battery
  • Lithium-ion battery diaphragm, preparation method thereof and lithium-ion battery

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preparation example Construction

[0019] The invention provides a preparation method of a lithium-ion battery separator, comprising: (1) melting and blending polyethylene, a pore forming agent, a crosslinking agent and a crosslinking aid to obtain a mixture A; (2) preparing the mixture A Forming into an initial film B, the gel content of the initial film B is less than 5% by weight; (3) performing high temperature crosslinking on the initial film B to form a crosslinked film C, the gel content of the crosslinked film C The glue content is 30-70% by weight; (4) stretching the crosslinked film C to obtain a stretched film D; (5) annealing the stretched film D to obtain a lithium-ion battery separator; wherein, the The melt index MI of the polyethylene is 0.02g / 10min~5g / 10min; relative to 100 parts by weight of the polyethylene, the amount of the crosslinking agent is 0.03~8 parts by weight, and the amount of the crosslinking aid It is 0.03 to 10 parts by weight.

[0020] According to the present invention, pref...

Embodiment 1

[0049] (1) Formula of polyethylene composition for lithium ion battery diaphragm:

[0050] The matrix resin is HDPE with MI=0.3g / 10min (density=0.960g / cm 3 ) 100 g, 0.7 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 1.1 g of triallyl isocyanurate.

[0051] (2) Lithium-ion battery diaphragm preparation:

[0052] Each component that forms the above formula is extruded and granulated in a low-shear twin-screw extruder (length-to-diameter ratio is 18 / 1, and the rotating speed of the screw is 100 rpm) to obtain mixture A, and the blending temperature is 140 °C, while testing the rheological curve of mixture A at 150 °C for 30 minutes, such as figure 1 shown. Depend on figure 1 It can be seen that during the melt blending process, the viscosity of the mixture A can remain basically unchanged under the test conditions, indicating that the formulation composition has good processing thermal stability and no crosslinking occurs. Mixture A was sampled and determined to have...

Embodiment 2

[0060] (1) Formula of polyethylene composition for lithium ion battery diaphragm:

[0061] The matrix resin is HDPE with MI=2g / 10min (density=0.955g / cm 3 ) 100 g, 0.7 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and 1.1 g of triallyl isocyanurate.

[0062] (2) Lithium-ion battery diaphragm preparation:

[0063] Each component that forms the above formula is extruded and granulated in a low-shear twin-screw extruder (length-to-diameter ratio is 18 / 1, and the rotating speed of the screw is 100 rpm) to obtain mixture A, and the blending temperature is 150 ℃, the rheological curve of the test mixture A is the same as that in Example 1, and basically remains the same, indicating that the processing heat stability of this formula composition is good, and no crosslinking occurs. Mixture A was sampled and determined to have a gel content of 0.5% by weight;

[0064] The mixture A was molded by tableting (the molding temperature was 145° C.) to obtain an initial film B, and the...

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Abstract

The invention relates to the field of a lithium-ion battery and specifically discloses a lithium-ion battery diaphragm with a promoted heat resistance, a preparation method thereof and a lithium-ion battery. The method comprises the following steps: (1) melting and blending polyethylene, cross-linking agent and cross-linking auxiliaries, thereby acquiring a mixture A; (2) molding the mixture A into an initial diaphragm B, wherein the gel content of the initial diaphragm B is less than 5wt%; (3) performing high-temperature cross-linking on the initial diaphragm B, thereby forming a cross-linking diaphragm C, wherein the gel content of the cross-linking diaphragm C is 30-70wt%; (4) stretching the cross-linking diaphragm C, thereby acquiring a stretched diaphragm D; (5) annealing the stretched diaphragm D, thereby acquiring the lithium-ion battery diaphragm, wherein the melt index of polyvinyl is 0.02g/10min-5g/10min, and in 100 weight parts of polyvinyl, the dosage of the cross-linking agent is 0.03-8 parts by weight and the dosage of the cross-linking auxiliaries is 0.03-10 parts by weight. The method can be adopted for preparing the lithium-ion battery diaphragm with promoted heat resistance.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery diaphragm, a preparation method and a lithium ion battery. Background technique [0002] Lithium-ion battery separator is an important part of lithium-ion batteries. It is an insulating porous film. It has the function of allowing electrolyte ions to pass through. Specifically, the separator needs a certain porosity and pore size distribution to allow ions to pass through normally. In addition, it provides safety during the use of lithium-ion batteries: on the one hand, it isolates the positive and negative electrodes to prevent them from directly contacting and short-circuiting; When the internal reaction heat of the battery is out of control due to external failure or internal short circuit, the diaphragm can normally self-close the pores at a lower temperature, cut off the positive and negative reactions of the battery, and stop the battery from work...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/491
CPCH01M10/0525H01M50/40H01M50/403H01M50/409H01M50/411Y02E60/10
Inventor 任冬雪陈学连梁文斌赖世燿孙苗苗孙小杰
Owner CHNA ENERGY INVESTMENT CORP LTD
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