Alkaline battery separator and alkaline battery using separator

• US 9,142,816 B2
• Filed: 09/06/2011
• Issued: 09/22/2015
• 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
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): Lewis, Ben
• Application Number:
  US13/823,128
• Publication Number:
  US 20130183569A1
• Time in Patent Office: 1,477 Days
• Field of Search: 429/129, 429/135, 429/141, 429/144, 429/145, 429/216, 429/235, 429/246, 429/255
• US Class Current: 1/1
• 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: 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:

a coarse layer comprising a first alkaline-resistant synthetic fiber, a first alkaline-resistant binder fiber, and at least two kinds of first alkaline-resistant cellulose fibers having different freeness values from each other; and

a dense layer comprising a second alkaline-resistant synthetic fiber, a second alkaline-resistant binder fiber, and a second alkaline-resistant cellulose fiber

wherein the coarse layer comprises the at least two kinds of the first alkaline-resistant cellulose fibers in a proportion of from 25 to 65% by weight of the coarse layer, the at least two kinds of the first alkaline-resistant cellulose fibers, as a whole, have a freeness value of from 350 to 650 ml, a difference in freeness values between one of the at least two kinds of the first alkaline-resistant cellulose fibers having a highest freeness value and one of the at least two kinds of the first alkaline-resistant cellulose fibers having a lowest freeness value is from 300 to 700 ml,

the dense layer is denser than the coarse layer, the second alkaline-resistant cellulose fiber has, as a whole, a freeness value of from 0 to 400 ml,

the alkaline battery separator has a maximum pore size of 65 μ

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

a difference in freeness values between the whole freeness value of the first alkaline-resistant cellulose fiber and the whole freeness value of the second alkaline-resistant cellulose fiber is from 100 to 450 ml.

2. The alkaline battery separator of claim 1, wherein the at least two kinds of the first alkaline-resistant cellulose fibers comprise the one of the at least two kinds of the first alkaline-resistant cellulose fibers having the lowest freeness value in a proportion of from 15 to 55% by weight.

3. The alkaline battery separator of claim 1, wherein the at least two kinds of the first alkaline-resistant cellulose fibers and the second alkaline-resistant cellulose fiber are optionally different from each other, and each comprises at least one member selected from the group consisting of a mercerized pulp and an organic solvent-spun cellulose fiber.

4. The alkaline battery separator of claim 3, wherein the mercerized pulp comprises at least one member selected from the 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 alkaline battery separator of claim 1, wherein each of the first alkaline-resistant synthetic fiber and the second alkaline-resistant synthetic fiber comprises a polyvinyl alcohol fiber.

6. The alkaline battery separator of claim 1, wherein the first alkaline-resistant binder fiber and the second alkaline-resistant binder fiber are optionally different from each other, and each comprises at least one member selected from the group consisting of a polyvinyl alcohol binder fiber and an ethylene-vinyl alcohol copolymer binder fiber.

7. The alkaline battery separator of claim 1, wherein each of the first alkaline-resistant synthetic fiber and the second alkaline-resistant synthetic fiber has a single fiber fineness of from 0.05 to 1 dtex.

8. An alkaline battery, comprising:

an alkaline battery separator of claim 1.

9. The alkaline battery separator of claim 1, wherein the separator has an air permeability of 11 to 40 cc/cm²/sec.