Battery gassing detector
AssigneeEHV Systems, Inc.
InventorJohn Santini
Life of this patent
Estimating the term…
Abstract
A gassing detector for use in modifying the charge rate in charging circuits for liquid electrolyte secondary cells. A light is reflected from the surface of the electrolyte into a photodetector. A discriminator circuit distinguishes the pulses in the photodetector output characteristic of the rippling caused by gassing of the cell and produces a signal to cause the charger to reduce the charge rate.
Claims11
An apparatus for detecting bubbling on the surface of a liquid, comprising:
- a. light emitting means for directing a light at the surface of the liquid;
- b. photodetector means for generating a signal responsive to the light reflecting from the surface of the liquid, having an input for the reflected light and an output responsive to the amount of liquid detected;
- c. said light emitting means and said photodetector means being located above the surface of the liquid;
- d. discriminator means for distinguishing signals caused by bubbling having an input connected to the photodetector means output and having an output responsive to the detection of bubbling in the liquid.
A battery gassing detector for determining the state of charge of a liquid electrolyte secondary battery, comprising:
- a. means for illuminating the surface of the liquid electrolyte, located above the surface having a light output shining on the surface;
- b. photodetector means having a light sensitive input and a signal output, located above the surface such that the light from the illuminating means is reflected from the surface onto the light sensitive input of the photodetector;
- c. discriminator means having an input connected to the signal output of the photodetector and an output responsive to the detection of a pattern of pulses in the output of the photodetector which is characteristic of bubbling.
The detector of claim 6 in which the discriminator means comprises:
- a. high-pass filter means connected to the signal input for attenuating pulses of duration longer than 1 millisecond, having an output for those pulses of 1 millisecond or shorter duration;
- b. current amplifier means having an input connected to the output of the high-pass filter, and an output current proportional to the input;
- c. a capacitor charged by the output of the current amplifier;
- d. a voltage reference for determining the state of capacitor charge which represents gassing;
- e. voltage comparator means with inputs connected to the capacitor and the reference, and an output responsive to the difference between the reference and the capacitor voltages, which reference is the output of the discriminator circuit.
The method of detecting bubbling on the surface of a liquid comprising the steps of:
- a. shining a light on the surface of the liquid from a position above said surface;
- b. measuring the reflected light from a position above the surface of the liquid;
- c. distinguishing the reflected light characteristic of bubbling from that of a still surface by the steps of filtering out all slow changes in measured light, accumulating the faster changes, and comparing the accumulated charge with a preset level indicative of bubbling.
Dependencies are inferred from the claim text.