Equalizer system and method for series connected energy storing devices

Patent · 01 January 1999

OSTI ID:872518

Rouillard, Jean ^[1]; Comte, Christophe ^[2]; Hagen, Ronald A ^[3]; Knudson, Orlin B ^[4]; Morin, Andre ^[5]; Ross, Guy ^[6]

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1. Saint-Luc, CA
2. Montreal, CA
3. Stillwater, MN
4. Vadnais Heights, MN
5. Longueuil, CA
6. Beloeil, CA

An apparatus and method for regulating the charge voltage of a number of electrochemical cells connected in series is disclosed. Equalization circuitry is provided to control the amount of charge current supplied to individual electrochemical cells included within the series string of electrochemical cells without interrupting the flow of charge current through the series string. The equalization circuitry balances the potential of each of the electrochemical cells to within a pre-determined voltage setpoint tolerance during charging, and, if necessary, prior to initiating charging. Equalization of cell potentials may be effected toward the end of a charge cycle or throughout the charge cycle. Overcharge protection is also provided for each of the electrochemical cells coupled to the series connection. During a discharge mode of operation in accordance with one embodiment, the equalization circuitry is substantially non-conductive with respect to the flow of discharge current from the series string of electrochemical cells. In accordance with another embodiment, equalization of the series string of cells is effected during a discharge cycle.

• Research Organization: United States Advanced Battery Consortium, Dearborn, MI (US)
• DOE Contract Number: FC02-91CE50336
• Assignee: Minnesota Mining & Manufacturing Co. (St. Paul, MN); Hydro-Quebec Corporation (Montreal, CA)
• Patent Number(s): US 5952815
• OSTI ID: 872518
• Country of Publication: United States
• Language: English

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