IL40682A - Bipolar electrode for battery cells - Google Patents

Claims (14)

1. A bipolar electrode for a cell of an electrical energy storage device which comprises a gas- and electrolyte-impervious barrier, a porous member held to a side of the barrier, with a plurality of passageways defined between the barrier and porous memberf the passageways extending substantially across the barrier and being adapted to carry electrolyte through them, and the porous member being adapted to pass electrolyte through it transversely with respect to the barrier.

2. An electrode according to Claim 1 wherein the impervious electrode barrier is of graphite, a highly electropositive metal coating is o a sid of the barrier opposite to the side f cing the porous member , and , the porous member is of carbon selected from the group consisting of amorphous and graphite, and is of a unitary structure having a porosity such that a cross-section comprises from 20 to 80% carbon, the pores in or passages through the porous carbo have an average diameter of 5 to 300 microns and the least transverse thickness of the porous carbo 13 rom 0.3 to 3 millimeters.

3. An electrode according to Claim 2 wherein the graphite barrier is of a thickness of 0.3 to 4 millimeters, the porous carbon barrier is from 1 to 5 times as thick as the graphite barrier, the passageways fo movement of electrolyte across the barriers are substantially straight, vertical and parallel to each other and are in the porous carbon member, and the porous carbon member is held to the graphite barrier by an electrolyte-resistant cement.

4. -4- The electrode of Claim 2 wherein the metal coating compris a metal selected from Group IIB and VIII.

5. -5- The electrode of Claim 2 wherein the metal in the metal coating is zinc.

6. -6- The electrode of Claim 1 further comprising gas dissolved within said electrolyte and means for passing the undissolved gas through holes in one barrier of the electrode.

7. -7- The electrode of Claim No. 1 wherein said electrolyte is an aqueous metal halide electrolyte and the gas is a halogen.

8. -8- The electrode of Claim No. 1 wherein said electrolyte is a Group IIB metal halide.

9. -9- The electrode of Claim No. 6 wherein the gas is chlorine or bromine.

10. -10- The electrode of Claim No. 6 wherein the holes through one side of the electrode for passing undissolved gas are present in the porous side. . .

11. -11- The electrode of Claim No. 6 wherein the holes in the first side range from about 0.1 to about 3.0 millimeters.

12. -12- The electrode of Claim No. 1 wherein the porous 40682/2 ^ side, the channel for electrolyte flow is formed*

13. A bipolar ceil of a high energy density secondary battery which comprises passageways, a porous member and a gas-and electrolyte-impervious barrier with a highly electropositive metal on a side thereo , and means or passing an aqueous electrolyte solution of a halid of the metal, with tlie elemental halogen of said halide, through the passages between the impervious and porous parts at a pressure suffcient to force the agueous electrolyte transversely through the porous member and into a reaction zone between such porous member and the impervious barrier having highly electropositive metal thereon, the reaction zone being that place between th electrodes where metal and halogen react to form metal halide and generate an electric current which can flow between th metal and halogen electrodes.

14. A bipolar cell according to Claim 13 wherein the impervious barriers are of graphite, the highly electropositive metal on the sides of the barriers is zinc, and is plated thereon, the porous member is of amorphous carbo or graphite, is of a unitary structure and has a porosity such that a cross-section comprises from 20 to 80% carbon (including graphite) , with the pores or passages through the carbon having an averag diameter of 5 to 300 microns, the passageways are substantially across the barriers, extending vertically and are flat, with widthsthickness ratios la the range of 2¾1 to 10 si, the electrodes are flat, th means for passing halogen-containing aqueous halide electrolyte solution through the passageways and through the- porous carbon is a pump and the means for removing 40682/2 electrolyte from the passageways includes a manifold duct connected with a plurality of passageways. -15- plating A bipolar cell according to Claim 14 wherein the zinc/on graphite and porous carbon portions of the cell are spaced apart by a frame member which, with the zinc and porous carbon electrodes and the electrolyte, make the cell. -16- A bipolar cell according to Claim 15 wherein the electrolyte is an aqueous solution of zinc chloride with elemental chlorine therein and the zinc plating is from 25 to 4,000 microns thick. -17- An electrical energy storage device comprising an electrode compartment with at least, one positive and one negative electrode therein, wherein the negative electrode is comprised of an oxidizable metal surface which will combine electrochemically with a halogen, and an electrolyte with halogen gas dissolved therein disposed in electrical contact with the positive and negative electrodes wherein at least one electrode is the electrode of Claim No. 1. -18- The device of Claim No. 17 wherein the electrodes are bipolar electrodes and the second side is an electrode impervious to the flow of gas or electrolyte therethrough. -19- The device of Claim No. 18 wherein the electrolyte is an aqueous metal halide electrolyte and the gas J.s a halogen. ♦ -20- The device of Claim No. 18 wherein the electrolyte is a Group IIB metal halide. -21- The device of Claim No. 18 wherein the gas is chlorine or bromine. -22- The device of Claim No. 18 wherein the electrolyte is zinc chloride. -23- The device of Claim No. 6 wherein the holes range from about 0.1 to about 3 millimeters . -24- The device of Claim No. 17 comprising a plurality of the cells having bipolar cells electrically connected together in series, with means for mixing the electrolyte from the cells, means for enriching the aqueous zinc chloride electrolyte with elemental chlorine, after electrolytic action has taken place and converted the chlorine to chloride, and means for recirculating the enriched electrolyte through the cells . -25- A process for producing electrical energy in an electrical energy storage device comprising passing an aqueous metal halicje electrolyte containing dissolved halogen into, through and out an electrode compartment with at least one porous positive and one negative electrode therein, wherein the negative electrode is comprised of an oxidizable metal surface, passing the positive electrode and passing undissolved gas through the holes in the electrode, thereby generating current. -26- The method of Claim 25 wherein the aqueous zinc chloride electrolyte containing dissolved chlorine is passed transversely through a porous carbon electrode, is enriched with chlorine after ionization of a portion of its original dissolved chlorine content, is mixed with the portion of the electrolyte that passed through the electrode compartment and is returned to said compartment, the mixing taking place either before or after enrichment with chlorine. -27- The process of Claim No. 25 wherein the negative electrode is impervious to the flow of gas or electrolyte therethrough. -28- The process of Claim No. 25 wherein the electrolyte is a Group IIB metal halide. -29- The process of Claim No. 25 wherein the gas is chlorine or bromine . -30- The process of Claim No. 25 wherein the electrolyte is zinc chloride. -31- The process of Claim No. 25 further comprising passing the electrolyte into the electrode at the bottom and passing the undissolved gas and the electrolyte out of the electrode at the top of the electrode. -32- through holes in the positive porous electrode. -33- The process of Claim No. 32 wherein the holes in the porous electrode range in size from about 0.1 to about 3.0 millimeters. For the Applicants DR. REINHOLD COHN AND PARTNERS