Battery separators comprising inorganic particles
Battery separators are generally provided. In some embodiments, the battery separators may comprise a non-woven web including a plurality of inorganic particles (e.g., silica). The non-woven web may include, in some embodiments, a plurality of relatively coarse glass fibers (e.g., having an average diameter of greater than about 1.5 microns), e.g., such that the non-woven web has a particular largest pore size and median pore size. The combination of inorganic particles with a non-woven web having features described herein may exhibit enhanced electrolyte stratification distance and/or reduced electrolyte filling time. In some embodiments, such improvements may be achieved while having relatively minimal or no adverse effects on another property of the battery separator and/or the overall battery.
1. A battery separator, comprising:
a non-woven web comprising:
a plurality of glass fibers; and
a plurality of inorganic particles,
wherein the non-woven web has a largest pore size of at least about 8 microns and less than or equal to about 25 microns, and
wherein the non-woven web has a median pore size of at least about 2.5 microns and less than or equal to about 6 microns.
2. A battery separator as in claim 1 , wherein the inorganic particles are present in an amount of greater than about or equal to about 3 wt % and less than or equal to about 30 wt % of the non-woven web.
3. A battery separator as in claim 1 , wherein the plurality of inorganic particles comprise silica.
4. A battery separator as in claim 1 , wherein the plurality of inorganic particles comprise precipitated silica.
5. A battery separator as in claim 1 , wherein the plurality of inorganic particles have an average specific surface area of greater than or equal to about 100 m 2 /g and less than or equal to about 850 m 2 /g.
6. A battery separator as in claim 1 , wherein the plurality of inorganic particles have an average particle size of greater than or equal to about 0.01 micron and less than or equal to about 20 microns.
7. A battery separator as in claim 1 , wherein the plurality of glass fibers have an average diameter of greater than or equal to about 2 microns.
8. A battery separator as in claim 1 , wherein the glass fibers are present in an amount of greater than or equal to about 50 wt % and less than or equal to about 97 wt % of the non-woven web.
9. A battery separator as in claim 1 , wherein the non-woven web further comprises a plurality of synthetic fibers, wherein the synthetic fibers are present in the non-woven web in an amount of greater than about 0 wt % and less than or equal to about 20 wt %.
10. A battery separator as in claim 9 , wherein the plurality of synthetic fibers comprises bi-component fibers.
11. A battery separator as in claim 1 , wherein the plurality of glass fibers have an average diameter of greater than or equal to about 1.5 microns.
12. A battery separator as in claim 1 , wherein the non-woven web has a thickness of at least about 0.05 mm and less than or equal to about 5 mm.
13. A battery separator as in claim 1 , wherein the non-woven web has an density of least about 100 g/m 2 /mm and less than or equal to about 250 g/m 2 /mm.
14. A battery separator as in claim 1 , wherein the non-woven web has an overall specific surface area of at least about 1 m 2 /g and less than or equal to about 100 m 2 /g.
15. A battery separator as in claim 1 , wherein the non-woven web has a tensile strength in the machine direction of the non-woven web greater than or equal to about 0.2 lbs/in and less than or equal to about 20 lbs/in.
16. A battery separator as in claim 1 , wherein the non-woven web has a puncture strength of at least about 1 N and less than or equal to about 20 N.
17. A battery separator as in claim 1 , wherein the non-woven web has a pressure loss of at least about 15% and less than or equal to about 30%.
18. A battery separator as in claim 1 , wherein the non-woven web has a percent thickness loss at 10 kPa of less than or equal to 30%.
19. A battery separator as in claim 1 , wherein the non-woven web has a percent thickness loss at 50 kPa of less than or equal to 7.8%.
20. A battery separator as in claim 1 , wherein the plurality of particles have an acid weight loss of less than 20%.
21. A battery separator as in claim 1 , wherein the non-woven web has a largest pore size of at least about 8 microns and less than or equal to about 18 microns.
22. A battery separator as in claim 1 , wherein the non-woven web has a median pore size of at least about 2.5 microns and less than or equal to about 4.5 microns.
23. A lead acid battery comprising the battery separator of claim 1 .