A device for measuring the discharge voltage of primary or secondary-cells

摘要

679,106. Batteries and cells; testing. GIBIAN, R. June 14, 1951 [June 21, 1949], No. 14150/51. Classes 37 and 53. In a device for measuring the discharge voltage of a cell independently of the internal resistive voltage drop but taking account of the depolarization voltage, a self-interrupting vibratory switch 5. (Fig. 1), operates at, e.g., 50 c.p.s. to alternately connect a gas depolarized primary cell 16, having a central tubular carbon electrode 2 sealed through a sleeve in the bottom of a zinc vessel 1 containing caustic potash solution, across an adjustable load 7 in series with a milliammeter 6, and across a high resistance voltmeter 13 or a voltage measuring potentiometer 10 and galvanometer 9. Switching impulses are avoided by bridging the vibrator contacts by condensers 12. Air or oxygen passes into the bore of the electrode 2 and diffuses through the pores of the carbon to the boundary of the electrode and electrolyte where it acts as a depolarizer. Since the action is sluggish, the state of depolarization does not substantially change while the cell is connected to the voltage measuring device, which indicates the E.M.F. of the cell minus the depolarization voltage for the load current indicated on milliammeter 6. The contact period on load may be arranged to be longer than that during voltage measurement. In a modification, Fig. 3 (not shown), the load resistances may be alternative current-controlling iron-hydrogen resistances and the voltage measuring device may be connected over a change-over switch to the off-load cell E.M.F., the voltage across the load resistance, and the vibratory switch. The vibratory switch may be replaced by a cyclically-operating electronic switch.