Battery separator structures

1. A multilayer composite sheet for use in a lead-acid battery, comprising

a) a base layer comprising paper or a glass fiber mat;

b) a layer of polymeric nanofibers bonded with discrete adhesive particles to a first surface of the base layer; and

c) a scrim layer bonded with discrete adhesive particles to a surface of the layer of nanofibers opposite the base layer.

2. The composite sheet of claim 1 , wherein the diameter of the nanofibers is in a range from 40 nm to 1000 nm.

3. The composite sheet of claim 1 , wherein the diameter of the nanofibers is in a range from 100 nm to 400 nm.

4. The composite sheet of claim 1 , wherein the layer of polymeric nanofibers has an average thickness in a range from 200 nm to 2000 nm.

5. The composite sheet of claim 1 , wherein the layer of polymeric nanofibers has an average thickness in a range from 800 nm to 2000 nm.

6. The composite sheet of claim 1 , wherein the layer of polymeric nanofibers has an average pore diameter in a range from 100 nm to 500 nm.

7. The composite sheet of claim 1 , wherein the base layer comprises paper.

8. The composite sheet of claim 1 , wherein each of the adhesive particles in b) and c) are hot melt adhesive particles.

9. The composite sheet of claim 1 , wherein the base layer comprises a glass fiber mat.

10. The composite sheet of claim 9 , wherein the glass fiber mat comprises borosilicate glass fibers.

11. The composite sheet of claim 9 , wherein the glass fiber mat comprises a sulfate salt and colloidal silica dispersed therein.

12. The composite sheet of claim 11 , wherein the glass fiber mat is a compressed mat capable of expanding in thickness after immersion in battery electrolyte.

13. A plate assembly for a lead-acid battery, comprising a lead plate having first and second opposing surfaces coated respectively with first and second layers comprising lead oxide, said first and second layers contacting first and second multilayer composite sheets respectively, each of said composite sheets comprising:

a) a paper base layer;

b) a layer of polymeric nanofibers bonded with discrete adhesive particles to a first surface of the paper base layer; and

c) a scrim layer bonded with discrete adhesive particles to a surface of the layer of nanofibers opposite the paper base layer;

wherein each of the first and second layers of the plate is adjacent and bonded to the paper base layer of the first and second multilayer composite sheets respectively on a second surface thereof opposite the first surface, and wherein the first and second multilayer composite sheets are adhered together so as to enclose the lead plate on three sides.

14. A plate assembly for a lead-acid battery, comprising a lead plate having first and second opposing surfaces coated respectively with first and second layers comprising lead oxide, at least one of said first and second layers contacting a multilayer composite sheet comprising:

a) a glass fiber mat base layer;

b) a layer of polymeric nanofibers bonded with discrete adhesive particles to a first surface of the glass fiber mat base layer; and

c) a scrim layer bonded with discrete adhesive particles to a surface of the layer of nanofibers opposite the glass fiber mat base layer;

wherein said at least one of the first and second layers of the plate is adjacent the glass fiber mat base layer of the multilayer composite sheet on a second surface thereof opposite the first surface.

15. The plate assembly according to claim 14 , wherein said first and second layers contact first and second multilayer composite sheets respectively;

wherein each of the first and second layers of the plate is adjacent the glass fiber mat base layer of the first and second multilayer composite sheets respectively on a second surface thereof opposite the first surface, and wherein the first and second multilayer composite sheets are adhered together so as to enclose the lead plate on three sides.