GB1360779A - Gas-depolarizable galvanic cells - Google Patents

Abstract

1360779 Metal-air cells ESB Inc 27 March 1973 14672/73 Heading H1B A miniature zinc-air cell is adapted to normal alkaline cell manufacture. The cell has a nickeled-steel casing 12 with a perforated base 14. A cathode assembly comprises a microporous PTFE layer 26, a nickel screen or grid 28, carrying a layer of carbon and PTFE or wax, an annular moulded-polymer support 72, and a separator layer 76 of aqueous polyacrylic acid gel. Portions 28 of the screen or grid 28 project through the moulding and are bent up into recesses 32 when the cathode assembly is pushed into the casing 12 to complete the electrode path to the casing. A preformed separator 42 is additionally used in some cases. The anode contact and cell closure assembly comprises two friction fitted dishes 52, 54 respectively of tinplated and nickel-plated steel and moulded into a polythene or nylon seating washer 64. The two dishes may be spot-welded at 56. The anode material (not shown) which fully occupies the upper part of the housing may be a gel of zinc powder, polyacrylic acid, and potassium hydroxide solution; the separator 42 being dispensed with. Alternatively the anode may be a pressed zinc pellet or compacted amalgamated zinc powder, pressing if desired being effected in the anode cup. In this case the separator 42 is fitted into the space 46 in the cathode assembly and is soaked with an electrolyte consisting of aqueous potassium hydroxide with dissolved zinc. In all cases the walls of the casing 12 are crimped over the sides of the anode cup, thereby applying a downward pressure to seal the mating faces of the moulded bodies 72 and 64 and applying a radial pressure to seal the casing 12 to the side wall 62 of the upper moulded body.