Battery diaphragm and battery using same

Abstract

A battery separator comprises: a divided compound fiber (A), a polyolefine compound fiber (B), as the necessary components, and, optionally, a non-woven fabric of a third synthetic fiber (C). Based on 100 weight % of the total amount of the constituent fibers, each of the divided compound fiber (A) or the polyolefine compound fiber (B) shall not exceed 60 weight %. Furthermore, the non-woven fabric has been subjected to a hydrophilic treatment. The divided compound fiber (A) comprises a methyl pentene polymer (formed of poly (4-methylpentene-1) or 4-methylpentene-1 and other olefine polymer) as a first component and a polyolefine polymer different from the first component or its copolymer as a second component. The second component is interleaved and adjacent to each other in fiber cross-section. Furthermore, at least one component in the second component is divided into more than one. The polyolefine compound fiber (B) comprises a high melting point component and a low melting point component.

Description

technical field [0001] The invention relates to a battery separator suitable for nickel-cadmium batteries, nickel-zinc batteries, nickel-hydrogen batteries and other alkaline storage batteries and a manufacturing method thereof. Background technique [0002] In recent years, nonwoven fabrics composed of polyolefin fibers such as polypropylene have been preferably used as battery separators, and battery separators in which nonwoven fabrics composed of polyolefin ultrafine fibers have been hydrophilically treated have been proposed. For example, in JP-A-5-186911 and JP-A-5-186964, the present applicant proposed that in a segmented composite fiber composed of a methylpentene polymer / polyolefin polymer combination, A fiber aggregate containing more than 60 wt% of sulfonated polyolefin fibers introduced with sulfonic acid groups. [0003] In JP-A-7-147154, it is proposed that the spunlaced non-woven fabric composed of more than 50 wt% polyolefin segmented composite fibers is sub...

AI Technical Summary

Problems solved by technology

For example, if the fiber aggregates of JP-A-5-186911 and JP-A-5-186964 are used as a battery separator, the strength of the nonwoven fabric after sulfonation treatment tends to be low, and the cost increases, which cannot be achieved. say ideal

In the battery separator of JP-A 7-147154, the split-type composite fiber composed of polyethylene / polypropylene is used as the main body, and the composite fusion bonded fiber composed of polypropylene / low-density polyethylene makes it thermally fused Bonding, so the strength of the nonwoven fabric is low, and it cannot be efficiently treated with water, etc., and the process is poor

The battery separator of JP-A-8-273654, which was studied to solve this problem, melts and bonds one component of the split-type composite fiber, low-melting point ultrafine fibers, to separate and entangle them, so although the non-woven Cloth strength is improved, but since the microfiber components themselves are welded to each other, it is difficult to ensure voids, and the liquid retention property is insufficient

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