ALKALINE BATTERY SEPARATOR AND ALKALINE BATTERY USING SEPARATOR

• US 20130183569A1
• Filed: 09/06/2011
• Published: 07/18/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Kuraray Company Limited
• Original Assignee: Kuraray Company Limited
• Inventors: Hayakawa, Tomohiro, Kawai, Hiroyuki, Kambe, Koichi
• Granted Patent: US 9,142,816 B2
• Time in Patent Office: Days
• US Class Current: 429/144
• CPC Class Codes: H01M 10/24 Alkaline accumulators
• CPC Class Codes: H01M 50/4295 Natural cotton, cellulose or wood
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/446 Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 50/449 having a layered structure
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Provided are an alkaline battery separator and an alkaline battery including the separator. The separator includes at least a coarse layer and a dense layer denser than the coarse layer. The coarse layer contains an alkaline-resistant cellulose fiber having a freeness value of 350 to 650 ml as a whole in the proportion of 25 to 65% by weight. The alkaline-resistant cellulose fiber includes at least two kinds of alkaline-resistant cellulose fibers having different freeness with each other. The difference in freeness value between the alkaline-resistant cellulose fibers having the highest and lowest freeness values is 300 to 700 ml. The dense layer contains an alkaline-resistant cellulose fiber which as a whole has a freeness value of 0 to 400 ml. The separator has a maximum pore size of 65 μm or smaller, and a liquid absorption capacity of 5 g/g or higher.

Claims

1. An alkaline battery separator comprising at least a coarse layer (A) and a dense layer (B) denser than the coarse layer,

the coarse layer (A) comprising an alkaline-resistant synthetic fiber (A), an alkaline-resistant binder fiber (A) and an alkaline-resistant cellulose fiber (A), and containing the alkaline-resistant cellulose fiber (A) in the proportion of 25 to 65% by weight therein,

the alkaline-resistant cellulose fiber (A) having a freeness value of 350 to 650 ml as a whole and including at least two kinds of alkaline-resistant cellulose fibers having different freeness with each other, in which the difference in freeness value between the alkaline-resistant cellulose fibers having the highest and lowest freeness values is 300 to 700 ml;

the dense layer (B) comprising an alkaline-resistant synthetic fiber (B), an alkaline-resistant binder fiber (B) and an alkaline-resistant cellulose fiber (B),

the alkaline-resistant cellulose fiber (B), as a whole, having a freeness value of 0 to 400 ml; and

the separator having a maximum pore size of 65 μ

m or smaller, and a liquid absorption capacity of 5 g/g or higher.

2. The separator as claimed in claim 1, wherein in the coarse layer (A), the proportion of the cellulose fiber having the lowest freeness value is 15 to 55% by weight based on the whole alkaline-resistant cellulose fiber (A).

3. The separator as claimed in claim 1 or 2, wherein the alkaline-resistant cellulose fiber (A) and the alkaline-resistant cellulose fiber (B) are the same or different, and each includes at least one member selected from a group consisting of a mercerized pulp and an organic solvent-spun cellulose fiber.

4. The separator as claimed in claim 3, wherein the mercerized pulp comprises at least one member selected from a group consisting of a mercerized hardwood pulp, a mercerized softwood pulp, a mercerized eucalyptus pulp, a mercerized esparto pulp, a mercerized pineapple pulp, a mercerized abaca pulp, a mercerized sisal pulp, and a mercerized cotton linter pulp.

5. The separator as claimed in any one of claims 1 to 4, wherein each of the alkaline-resistant synthetic fiber (A) and the alkaline-resistant synthetic fiber (B) includes a polyvinyl alcohol fiber.

6. The separator as claimed in any one of claims 1 to 5, wherein the alkaline-resistant binder fiber (A) and the alkaline-resistant binder fiber (B) are the same or different, and each includes at least one member selected from a group consisting of a polyvinyl alcohol binder fiber and an ethylene-vinyl alcohol copolymer binder fiber.

7. The separator as claimed in any one of claims 1 to 6, wherein each of the alkaline-resistant synthetic fiber (A) and the alkaline-resistant synthetic fiber (B) has a single fiber fineness of 0.05 to 1 dtex.

9. An alkaline battery comprising a separator as recited in any one of claims 1 to 8.

8. An alkaline battery separator comprising at least a coarse layer (A) and a dense layer (B) denser than the coarse layer:

each of the coarse layer (A) and the dense layer (B) comprising an alkaline-resistant synthetic fiber, an alkaline-resistant binder fiber and an alkaline-resistant cellulose fiber, and

the separator having a maximum pore size of 65 μ

m or smaller, an air permeability of 13 cc/cm²/sec or higher, and a ring crush strength of 200 g or stronger.