Circuit for protecting storage cells

Meinhold

[45] Dec. 1, 1981

[54] CIRCUIT FOR PROTECTING STORAGE CELLS

[75] Inventor: Henner Meinhold, Sandhausen, Fed. Rep. of Germany

[73] Assignee: Brown, Boveri & Cie
Aktiengesellschaft,

Mannheim-Kafertal, Fed. Rep. of
Germany

[21] Appl. No.: 35,270

[22] Filed: May 1, 1979

[30] Foreign Application Priority Data

May 5, 1978 [DE] Fed. Rep. of Germany 2819584

Sep. 7, 1978 [DE] Fed. Rep. of Germany 2838996

[51] Int. CI.' H02J7/04

[52] U.S. CI 320/6; 320/18;

320/36

[58] Field of Search 320/6, 15-18,

320/35, 36, 43

[56] References Cited

U.S. PATENT DOCUMENTS

3,102,222 8/1963 Harmer 320/15 X

3,221,239 11/1965 Langer et al 320/17

3,343,058 12/1967 Deschamp et al 320/17

3,348,117 10/1967 Howden 320/18

3,393,355 7/1968 Whoriskey et al 320/18

3,496,442 2/1970 Carlisle 320/18

4,061,955 12/1977 Thomas et al 320/15 X

FOREIGN PATENT DOCUMENTS

698137 11/1964 Canada 320/17

Primary Examiner—Robert J. Hickey
Attorney, Agent, or Firm—Herbert L. Lerner

[57] ABSTRACT

Battery formed of electrochemical storage cells of the alkali metal and chalcogen type in series or groups of several parallel-connected storage cells connected in series. To assure uniform charging and discharging of the storage cells, each series-connected cell or each group of parallel-connected cells, has parallel-connected to the cell or group of cells, a protective circuit. Upon reaching a given maximum charge or discharge, a cell or group of cells, the circuit acts to bridge i.e. short the cell or group of cells which has reached a maximum charge or discharge, and prevent further charge or discharge of such cell or group of cells. The circuit is functionally Connected to a switch which is conductively conitectible directly to the negative and positive electrodes of the cells and to the electric terminals. The protective circuit is directly connected to both terminals and the storage cell to at least one of the two terminals via the switch.

19 Claims, 8 Drawing Figures