Method and apparatus for measuring the state of charge of a battery by monitoring reductions in voltage
US4193026A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1978 |
| Grant date | Mar 11, 1980 |
| Priority date | — |
| Expiry date | Aug 25, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/3648
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus are disclosed for measuring the state of charge of a battery. The apparatus comprises threshold means for sensing reductions below a threshold level in the output terminal voltage of the battery and for producing a signal in response thereto and means for integrating said signal over a plurality of such reductions. The output of the integrating means is indicative of the state of charge of the battery. In a preferred embodiment the signal comprises a series of pulses whose number is proportional to the time that the terminal voltage is below the threshold value and the integrating means counts such pulses. Alternatively, a single pulse may be produced and counted for each time the output terminal voltage is reduced below the threshold level. In another embodiment, the signal from the threshold means is integrated directly to develop a representation of the state of charge of the battery. Circuits are also disclosed using a plurality of threshold means connected in series or in parallel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.