Apparatus and methods for estimating the state-of-charge of a power source
US7405537B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2004 |
| Grant date | Jul 29, 2008 |
| Priority date | — |
| Expiry date | Feb 2, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/3648
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus are provided for estimating the remaining state-of-charge of a non-rechargeable power source, such as a back-up battery for an electronic module normally connected to a primary power source. A processor within the electronic module implements a prediction algorithm, in order to monitor the temperature of the back-up attery, and to calculate various current draws of the back-up battery. The processor adjusts the nominal self-discharge rate of the back-up battery in accordance with the measured temperatures, and calculates an adjusted self-discharge quantity. The processor also accumulates current draw data and reduces the initial state-of-charge value of the back-up battery by the temperature-adjusted self-discharge quantity and the cumulative current draw quantities to determine a remaining state-of-charge of the back-up battery. At a predetermined state-of-charge threshold level, an indicator can be activated to advise a user to replace the back-up battery.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.