Lead-acid battery separators, electrodes, batteries, and methods of manufacture and use thereof
View Patent ↗New or improved battery separators for lead-acid batteries that include a carbon or mineral additive applied to the separator. In possibly preferred embodiments, the battery separator may include engineered carbon materials applied to the battery separator to modify sulfate crystal formation while decreasing the detrimental consequences of excessive gas evolution into the negative electrode itself. In one embodiment, a method of enhancing the lead-acid energy storage performance of a lead-acid battery may include delivering carbon to the negative active material surface of the battery separator where the carbon may effectively enhance charge acceptance and improve life cycle performance of a lead-acid battery.
1. A battery separator for a lead-acid battery with enhanced lead-acid energy storage performance comprises:
a coating applied to a silica based material filled, polyolefinic lead acid battery separator, the coating comprising an engineered carbon material having a surface area (BET) of from 1500 to 3000 sqm/g;
wherein the battery separator has two surfaces, one surface which faces a positive electrode of a battery and one surface which faces a negative electrode of a battery and wherein the coating is placed on the surface which faces the negative electrode of the battery.
2. The battery separator of claim 1 wherein the coating provides sulfate crystal formation while decreasing the detrimental consequences of excessive gas evolution into a negative electrode.
3. The battery separator of claim 2 wherein the engineered carbon material is selected from the group consisting of: carbon black; graphite; activated carbon; and combinations thereof.
4. The battery separator of claim 2 wherein the engineered carbon material is selected from the group consisting of: graphite; activated carbon; carbon black; graphenes and associated structural analogs; dendritic forms of carbon; nanocarbon materials derived from various manufacturing methods; structured carbonaceous material; carbon monolithic and carbon multi-component sol-gel materials; the like, and combinations thereof.
5. The battery separator of claim 4 wherein the coating is derived from an aqueous coating solution having:
0.5 wt. %-10 wt. % of a surfactant; and
carbon black in a finely divided powdered form dispersed into the aqueous surfactant solution.
6. The battery separator of claim 5 wherein the surfactant being an ionic surfactant.
7. The battery separator of claim 6 wherein the ionic surfactant being a sodium dihexylsulfosuccinate in a concentration in the range of 2-3 wt/%.
8. The battery separator of claim 7 wherein the carbon black having a concentration selected from the group consisting of: 1-80% w/w; 2-60% w/w; and 2-30% w/w.
9. The battery separator of claim 8 wherein the porous nature of the separator allowing for rapid adsorption of the carbon dispersion on the surface with negligible penetration of the carbon particles into the pore structure of the separator.
10. The battery separator claim 9 whereby the separator may be coated by methods selected from the group consisting of: gravure roller; reverse-gravure; slot-die methods; pneumatic spray methods; dip coating methods; paint brush; sponge application; the like; and combinations thereof.
11. The battery separator of claim 10 wherein the thickness of the carbon coating being adjustable to meet the design parameters of the electrode plate spacing in the battery, whereby coating thickness may be adjusted from sub-micron to several hundred microns.
12. The battery separator of claim 1 wherein pressure exists between the plate and the separator to maintain contact between the plate, the coating, and the separator.
13. The battery separator of claim 12 wherein the coating may be employed on any profile or topological property present on the separator negative surface.
14. A lead acid battery comprising the battery separator of claim 1 .