Charge equalization of series connected cells or batteries
US5594320A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1994 |
| Grant date | Jan 14, 1997 |
| Priority date | — |
| Expiry date | Sep 9, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02J7/0018
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An equalizer for equalizing the charge on several series-connected cells includes a transformer having plural windings on a core corresponding to the number of cells. The windings are tightly coupled to one another. A switching device such as a MOSFET is connected to each of the windings, and a winding and a switching device are connected across each of the cells. The switching devices are simultaneously switched at a relatively high frequency, e.g., 20 Hz, and the voltage across the highest charged cell appears across each of the windings when the switching devices are on. Current flows from the most highly charged cell to a cell or to cells of lower charge, with the charging current being proportional to the difference in voltage between the highest charged cell and each of the lesser charged cells. Equalization is carried out with very little power consumption by the equalizer, allowing charging to take place in a rapid manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.