GB1299435A - Improvements relating to the charging of electric storage battery cells - Google Patents

Abstract

1299435 Battery-charging systems ALKALINE BATTERIES Ltd 11 March 1970 [14 March 1969] 13601/69 Heading H2H A method of charging electric storage battery cells comprises passing a charging current through the cell and periodically reversing the direction of the current through the cell, the reversals being produced automatically and each charge period and each discharge period being of predetermined duration. The circuit for charging the battery 52 from a D.C. source 50 consists of an A.C. source 30, a bridge rectifier 32, a voltage regulator including a Zener diode 36 a unijunction transistor 10 in a circuit for timing the battery charging period and a unijunction transistor 20 in a circuit for timing the battery discharging period. Initially relay coils 17, 27, 40 have their contacts 17/1-17/3, 27/1, 27/2, 40/1-40/4 in the positions shown and the battery 52 is charged by the source 50 as a capacitor 13 charges, a switch 45 being closed. When the capacitor voltage reaches the threshold voltage of the transistor 10, the relay coil 17 is energised thus closing the contact 17/2 to initiate the charging of a capacitor 23 and closing the contact 17/3 to energize the relay 40 thereby closing the contacts 40/3, 40/4 and reversing the connections of the battery 52 to the D.C. source to commence discharging the battery. When the voltage across the capacitor 23 reaches the threshold voltage of the transistor 20, the relay 27 is energized thus opening the contacts 27/1, 27/2 to de-energize the relay 17. The relay 40 and the battery discharging time circuit are therefore also de-energized and the contacts 40/1, 40/2 are closed to re-connect the battery 52 for a charging period.