Lead acid battery with titanium core grids having titanium suboxide coating

Abstract

A lead acid electric storage battery uses conventional lead-acid secondary battery chemistry. The battery may be a sealed battery, an unsealed battery or a conventional multi-cell battery. The battery has a set of positive battery grids (plates) which are constructed with a body portion o stamped f thin titanium metal having a thickness preferably in the range 0.1 mm to 0.9 mm and most preferably 3 mm to 4 mm. The titanium is coated, on all sides, with titanium sub-oxide, a conductive ceramic. Typically the battery would have over 250 grids in a 12 inch long battery case.

Claims

1. A lead-acid battery comprising a plurality of positive and negative battery grids with separators therebetween: (a) at least some of said positive grids being a titanium alloy (b) said positive titanium alloy grids having a metal body portion and said positive titanium alloy grids having a thickness of less than 1 mm and not being a foil; (c) one of said positive titanium alloy grids forming a plane with an imaginary line perpendicular thereto, said battery having at least 10 of said positive titanium alloy grids perpendicularly aligned along 1 inch (25.4 m) of said imaginary line; and (d) said positive titanium alloy grids including a protective coating of an electrically conductive ceramic of titanium subdioxide Magneli phase whose formula is Tix.On.sub.2n1 (where n is an integer 7 or 9 (e) and a coating of lead on said titanium subdioxide coating.

2. A lead-acid battery as in claim 1 wherein the lead free titanium alloy positive grids each contains from 0.02% to 0.2% selected from the group consisting of palladium and ruthenium.

3. A lead-acid battery comprising a plurality of positive and negative battery grids with separators therebetween; (a) at least some of said positive grids being lead-free titanium grids; (b) said titanium grids having a metal body portion and said titanium grids having a thickness of less than 0.9 mm and not foil; (c) each of said titanium grids forming a plane having an imaginary line perpendicular thereto, said battery having at least 5 cf said positive titanium grids perpendicularly aligned along 1 inch (25.4 mm) of said imaginary line; wherein the titanium is a titanium alloy containing 0.4% to 0.01% selected from the group consisting of palladium and ruthenium (d) and protective coating of an electrically conductive ceramic of titanium subdioxide Magneli phase whose formula is Tix.On.sub.2n1 (where n is an integer 7 or 9)

4. A lead-acid battery comprising a plurality of positive and negative battery grids with separators therebetween; (a) at least some of said positive grids being lead-free titanium grids; (b) said titanium grids having a stamped metal body portion and said grids having a thickness of less than 0.9 mm and not being a foil; (c) each of said titanium grids forming a plane having an imaginary line perpendicular thereto, said battery (d) said grids having a protective coating selected from the group consisting of titanium suboxide Magneli phase having the general formula Ti.sub.x O.sub.y, wherein the ratio of y to x is less than 2.selected from the group consisting of Ti.sub.4 O.sub.7, Ti.sub.5 O.sub.9, Ti.sub.6 O.sub.11, Ti.sub.7 O.sub.13, Ti.sub.8 O.sub.15 and Ti.sub.9 O.sub.7. (e) and a coating of lead on said titanium subdioxide coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings:

[0027] FIG. 1 is a top plan view of a finished positive grid of the present invention.

[0028] The grid 13 of FIG. 1 is formed from a titanium thin sheet (thin coil). Its thickness, for starter batteries or auto batteries for electric and hybrid cars, is in the preferred range of 0.1 mm to 0.7 mm and most preferably 0.2 mm to 0.4 mm and in any event, less than 0.7 mm. Most preferably the thickness of the core is about 0.3-0.4 mm for those batteries.

[0029] The grid 13 of FIG. 1 is formed from a titanium thin sheet (thin coil). Its thickness is in the preferred range of 0.05 mm to 0.9 mm and most preferably 0.4 mm to 0.5 mm and in any event, less than 0.9 mm. Preferably the thickness of the plate is about 0.3-0.4 mm. The grid 13, shown in FIG. 1, is 120.65 mm.high and 142.88 mm. wide. The grids may be thin, for example, as thin as the thickness of the side wall of an aluminum beverage can which has a thickness of about 0.1 to 0.2 mm. Titanium has good electrical conductivity compared to lead; it is stronger than lead; it is lighter than lead; however it is not completely corrosion resistant to the dilute sulfuric acid (battery acid) used in lead acid batteries.

[0030] The grids are preferably formed from a titanium alloy containing between 0.9% and 0.009% of either ruthenium or palladium or both ruthenium and palladium. The preferred range in the titanium alloy is 0.2% to 0.01% of palladium or ruthenium or both, most preferably 0.2% to 0.02%.

[0031] The titanium grids, after forming and cleaning are coated with a protective coating.