Diaphragm used for lithium-ion storage battery and manufacturing method thereof

A secondary battery and lithium-ion technology, which is applied to battery components, circuits, electrical components, etc., can solve the problems of melt mixing uniformity, pore-forming uniform product yield, diaphragm tensile strength and puncture Poor strength, increased uncontrollability of pore structure, etc., to achieve excellent puncture strength, excellent tensile strength, and good cycle characteristics

Active Publication Date: 2013-10-16
乐凯胶片股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The Chinese patent application number 200480028364.5 discloses a separator for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery using it. The separator has the following defects: in order to increase the pore size and porosity, in thermoplastic resin The addition of a large proportion of inorganic fillers deteriorates the continuity of the diaphragm, and the performance of the diaphragm such as tensile strength and puncture strength deteriorates; since the structure of the pores formed after the addition of fillers is largely dependent on the properties of the fillers, Including the particle size, shape, structure, compatibility and content of fillers, etc., which increase the uncontrollability of the pore structure; in addition, due to the large amount of fillers, the mixing uniformity of the melt, the uniformity of pore formation and the The yield of the product causes difficulties

Method used

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preparation example Construction

[0044] The preparation method of the present invention can be described in detail as:

[0045] Mix the polypropylene resin, nucleating agent and antioxidant, plasticizer and antioxidant in proportion if necessary, then use known single-screw extruder, twin-screw extruder, mixing roller Or twin-shaft kneading machine melts and extrudes at 200-250°C, and then cools the cast sheet, wherein the temperature of the cast sheet roll is 50-100°C, and the temperature of the cast sheet is higher than 100°C, the crystallization speed of polypropylene is fast, and the resulting Polypropylene spherulites are too large, and the number of crystals is small, the compactness of the sheet is poor, the porosity of the stretched film is low, and the tensile strength and puncture strength are reduced; the casting temperature is lower than 50 °C, and the crystal nucleus in the crystal system If the number increases, the number of crystallites increases, the number of spherulites decreases, the cryst...

Embodiment 1

[0052] F103H (weight-average molecular weight: 400,000, melt index is 3.0 g / 10min, isotacticity is 94%) manufactured by the polypropylene resin Prime Polymer company of mixing 100 parts, the organic machine nucleating agent sorbitol Bian of 0.3 parts Fork derivatives EC-1 (Japan EC company), 0.5 part of hygroscopic antistatic agent Atmer 290G (Swiss Ciba company production), 0.5 part of hindered phenolic main antioxidant Igno 1010 (four [β -(3.5-di-tert-butyl, 4-hydroxyphenyl) propionate] pentaerythritol) and phosphite secondary antioxidant 168 (tris(2.4-di-tert-butylphenyl) phosphite ) compound antioxidant and 8 parts of hardened castor oil mixed in a ratio of 1:2 to obtain a premix, the above premix is ​​melted and kneaded at a temperature of 250°C to form a melt, and at a temperature of 220°C, The melt was extruded from the T-shaped die of the extruder, and the temperature of the casting roll was adjusted to 55°C to obtain a polypropylene sheet with a sheet thickness of 0.5...

Embodiment 2

[0054] Mix 100 parts of F144H (weight-average molecular weight: 350,000, melt index 4.1g / 10min, isotacticity 98%) manufactured by Prime Polymer Co., 0.2 parts of organic phosphate nucleating agent NA -11 (Japan Asahi Denka Corporation), 1.0 parts of hygroscopic antistatic agent Atmer 290G (produced by Ciba, Switzerland), 1.0 parts of hindered phenolic main antioxidant Igno 1010 (tetra[beta-(3.5-di-tert-butyl ,4-hydroxyphenyl)propionic acid]pentaerythritol) and phosphite secondary antioxidant 168 (tris(2.4-di-tert-butylphenyl)phosphite) mixed in a ratio of 1:1 Composite antioxidant, 5 parts of hardened castor oil to obtain a premix, the above premix is ​​melted and kneaded at a temperature of 250°C to form a melt, and at a temperature of 220°C, the melt is produced by the T of the extruder Extrude from the mold head, adjust the temperature of the casting roll to 70°C to obtain a polypropylene sheet with a sheet thickness of 0.5mm, then perform plasma discharge treatment at 70°C...

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PUM

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Abstract

The invention discloses a diaphragm used for a lithium-ion storage battery and a manufacturing method thereof. The porosity of the diaphragm is 50%-70%, the average pore size of the diaphragm is 0.1-0.3um, and the largest pore size to the average pore size of the diaphragm is 1.10-1.25. The preparing method of the invention has simple process, and the porosity and the pore size of the diaphragm are controlled through the synergistic effect of plasma discharging processing technology and a nucleating agent, thereby solving the problem that troubles are brought for mixing of melt and uniformityof pore forming as the vast scale of inorganic fillers are added into the diaphragm for increasing the pore size and porosity.

Description

technical field [0001] The invention belongs to the field of new energy, and in particular relates to a diaphragm for a lithium ion battery and a preparation method thereof. Background technique [0002] Lithium ion secondary batteries having high energy density and light weight have been used in a wide range of fields due to weight reduction and miniaturization of electronic equipment. Lithium-ion secondary batteries are mainly composed of positive electrode, negative electrode, non-aqueous electrolyte and separator. [0003] A separator for a lithium ion secondary battery must satisfy requirements of not preventing ion conduction between electrodes, retaining an electrolyte solution, having solvent resistance to the electrolyte solution, and the like. The separator of the lithium ion secondary battery is mainly a porous film composed of a thermoplastic resin such as polyethylene or polypropylene. [0004] With the application of high-capacity power lithium-ion batter...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/18H01M2/16
CPCY02E60/12Y02E60/10
Inventor 郑文耀柳艳敏韩继庆张永升千昌富
Owner 乐凯胶片股份有限公司
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