GB1141507A - Improvements relating to electric storage batteries - Google Patents

Abstract

1,141,507. Accumulators. ALKALINE BATTERIES Ltd. 30 Nov., 1966 [1 Sept., 1965], No. 37337/65. Addition to 1,080,992. Heading H1B. The invention comprises a multiplate alkaline storage cell in which the electrolyte level is normally above the top of the plates. The upper parts of the plates are separated by absorbent gas permeable material and contain recesses in their surfaces bounded on their outer side by separator material. The plates are mounted in a compartment which is closed at the top but communicates below the liquid level with an expansion space so that if gases are evolved during charging they depress the electrolyte surface below the tops of the plates but the exposed parts of the plates are still in contact with electrolyte absorbed in the separator material. In a particular embodiment an alkaline cell has alternate Ni and Cd plates comprising metal pockets containing active material occasionally separated by recesses 14. The plates may be separated at the top by woven or felted material 12, at the bottom by pins or rods of rubber or plastics material 15 and at the edge by insulators 16. Gas liberated during charging collects in hood 19, forcing the liquid level outside the hood to rise and air to escape through vented plug 21. In other embodiments the pockets and recesses in the plates may be vertical rather than horizontal; the hood may extend to the bottom of the plates but have open - ings above the bottom of the absorbent separators and the cell as a whole may normally be gas tight having a gas tight stopper and/or a safety valve. The expansion space may be of bellows construction or may accommodate liquid merely by compression of the gas inside it. The cell may have a negative plate of greater capacity than the positive plate so that O 2 is evolved during charging rather than H 2 and may be charged from a source of constant potential.