GB1258502A - - Google Patents

Abstract

1,258,502. Zinc-halogen rechargeable electric battery. UNIGATE Ltd. 11 Feb., 1970 [21 Feb., 1969], No. 9548/69. Heading H1B. [Also in Division F1] A halogen storage electrode structure for a rechargeable zinc-halogen cell or battery comprises a substrate 1 of an anodizable metal of Group IV A to VA of the Periodic Table preferably Ti, Ta, Zr of alloys of two or all of such metals having permanently associated therewith at least one coherent stratum of porous carbon 3. The substrate 1 is preferably in the form of an open mesh such as expanded metal, an apertured or porous sheet. The titanium substrate may have a semi-conducting coating of nitride, mixed oxide or boride. The porous carbon is preferably of particulate or granule form bonded with a synthetic resin powder such as polyethylene, PVC, PTFE, polypropylene, polychloroprene, nylon or rubber nitrile and the mixture of carbon and resin may be bonded to the substrate under pressure. Alternatively, carbon powder may be bonded with the resin dissolved in a solvent using an inert filler such as ZnCl 2 , which is subsequently leached. Quarternary ammonium compounds and silica gel may be added to the carbon. As shown in Figs. 1, 2, the storage electrode may be formed of at least two of the above structures spaced apart by plastics member 5 at the top, and covered with a synthetic resin material 4 in sheet form, which leaves the outer surfaces of the carbon layer 3 free, and leaves one end of the electrode open to permit gas access to the enclosed space between the structures. Spacing members 6, 7 at the bottom are extended to form a gas channel and the members can be snapped together to unite the electrodes in a tight structure over the length of the cells in the battery. The other electrode in the cell or battery is preferably a zinc-bearing electrode comprising the substrate as defined above coated with zinc or a zinc-containing alloy or salt. Liquid zinc halide is used as electrolyte which may contain Hg, In or Ga, polyelectrolytes such as polyvinyl alcohol, thiourea, KCl and HClO. The cell or battery, Fig. 8, may comprise casing 11, titanium end walls 22 and titanium walls electrically connected. to and separating the electrodes, halogen has inlet to the upper part of the casing and communicating with the open bottom portions 8 of the carbon metal electrodes which form common channel 24. Gas space 25 is provided above the electrodes. Casing top 20 has a pressure release valve communicating via pipe 27 and vents 28 to space 25. The battery or cell is in a halogen gas circuit including a halogen gas cylinder, a pressure regulator valve, an ultra-violet lamp for removal of undesirable gases such as hydrogen, and a halogen gas liquefier, the liquefier being connected to the cylinder and the lamp being in the circuit between the valve and the liquefier.