Glass fiber separators for batteries and method for making such separators

• US 20020142226A1
• Filed: 10/09/2001
• Published: 10/03/2002
• Est. Priority Date: 07/01/1996
• Status: Active Grant

• Current Assignee: Hollingsworth & Vose Company
• Original Assignee: Hollingsworth & Vose Company
• Inventors: Harmon, Frank C. Jr., Zguris, George C.
• Granted Patent: US 6,495,286 B2
• Time in Patent Office: Days
• US Class Current: 429/247
• CPC Class Codes: H01M 10/121 Valve regulated lead acid batteries [VRLA]
• CPC Class Codes: H01M 50/437 Glass
• CPC Class Codes: H01M 50/44 Fibrous material
• 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 50/494 Tensile strength
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A glass fiber Separator material is disclosed. The separator is composed of a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μm, and at least 5 percent w/w of which have a fiber diameter less than 1 μm, and, distributed through the glass fibers, and from 0.2 percent w/w to 20 percent w/w of cellulose fibrils. The fibrils are from a slurry having a Canadian freeness sufficiently low that the separator material has a tensile strength greater than an otherwise identical separator where glass fibers having an average diameter greater than 1 μm replace the cellulose fibrils.

Claims

1. A glass fiber separator material comprising a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μ

m, and, distributed through the glass fibers, from 0.2 percent w/w to 20 percent w/w of cellulose fibrils from a slurry having a Canadian freeness not greater than 120 cc.

5. A glass fiber separator material as claimed in claim 1 wherein the cellulose fibrils are impregnated with a solidified, synthetic resin.

6. A glass fiber separator material as claimed in claim 5 wherein the solidified synthetic resin with which the cellulose fibrils are impregnated is a solidified, synthetic latex.

7. A glass fiber separator material as claimed in claim 1 wherein the cellulose fibrils are redwood fibrils or cedar fibrils.

8. A glass fiber separator material as claimed in claim 1 wherein the celllulose fibrils are from a slurry which has a Canadian freeness not greater than 100 cc.

9. A glass fiber separator material as claimed in claim 1 wherein the cellulose fibrils adjacent one of the two opposed major surfaces are impregnated with a solidified, synthetic resin, while the cellulose fibrils adjacent the other of the two opposed major surfaces are not so impregnated.

10. A glass fiber separator material as claimed in claim 9 wherein the cellulose fibrils are impregnated with a solidified, synthetic latex.

11. A glass fiber separator material as claimed in claim 1 wherein there are also hydrophobic synthetic fibers in the mass of glass fibers, the synthetic fibers are intermeshed with the glass fibers and with one another, and the size distribution of the glass fibers and the proportions of glass and synthetic fibers are such that the separator has an absorbency for a sulfuric acid electrolyte of from 75 percent v/v to 95 percent v/v.

12. A glass fiber separator material as claimed in claim 11 wherein the hydrophobic synthetic fibers include polyethylene fibers, polypropylene fibers acrylic fibers or polyester fibers.

13. A glass fiber separator material as claimed in claim 1 wherein there are also hydrophobic side by side or shell-core bicomponent fibers which include polyethylene, polypropylene, acrylic or polyester materials.

2. A glass fiber separator material comprising a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μ

m, and at least 5 percent w/w of which have a fiber diameter less than 1 μ

m, and, distributed through the glass fibers, from 0.2 percent w/w to 20 percent w/w of cellulose fibrils from a slurry having a Canadian freeness not greater than 650, and sufficiently low that a battery made with the separator has a service life, when cycled, at least at least 10 percent greater than an otherwise identical battery made with a separator where glass fibers having an average diameter greater than 1 μ

m replace the cellulose fibrils.

3. A valve regulated lead/sulfuric acid recombinant storage battery comprising a plurality of lead plates in a closed case, a fibrous sheet plate separator between adjacent ones of said plates, and a body of a sulfuric acid electrolyte absorbed by each of said separators and maintained in contact with each of the adjacent ones of said plates, each of said separator sheets comprising a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μ

m, and at least 5 percent w/w of which have a fiber diameter less than 1 μ

m, and, distributed through the glass fibers, from 0.2 percent w/w to 20 percent w/w of cellulose fibrils from a slurry which has a Canadian freeness not greater than 120 cc, and is sufficiently low that the separator material has a tensile strength at least about 10 percent greater than an otherwise identical separator containing a like amount of cellulose fibrils having a Canadian freeness of about 650 cc.

4. A valve regulated lead/sulfuric acid recombinant storage battery comprising a plurality of lead plates in a closed case, a fibrous sheet plate separator between adjacent ones of said plates, and a body of a sulfuric acid electrolyte absorbed by each of said separators and maintained in contact with each of the adjacent ones of said plates, each of said separator sheets comprising a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μ

m, and at least 5 percent w/w of which have a fiber diameter less than 1 μ

m, and, distributed through the glass fibers, from 0.2 percent w/w to 20 percent w/w of cellulose fibrils from a slurry which has a Canadian freeness not greater than 650 cc, and sufficiently low that the battery has a service life, when cycled, at least 10 percent greater than a battery made with an otherwise identical separator where glass fibers having an average diameter greater than 1 μ

m replace the cellulose fibrils.

14. A sealed lead/sulfuric acid recombinant storage battery comprising a plurality of lead plates in a closed case, a fibrous sheet plate separator between adjacent ones of said plates, and a body of a sulfuric acid electrolyte absorbed by each of said separators and maintained in contact with each of the adjacent ones of said plates, each of said separator sheets comprising a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 μ

m, and at least 5 percent w/w of which have a fiber diameter less than 1 μ

m, and, distributed through the glass fibers, from 0.2 percent w/w to 20 percent w/w of cellulose fibrils from a slurry having a Canadian freeness not greater than 650 cc, and sufficiently low that the separator material has a tensile strength greater than an otherwise identical separator where glass fibers having an average diameter greater than 1 μ

m replace the cellulose fibrils.