Apparatus for detecting cell reversal in rechargeable batteries
AssigneeOvonic Battery Company, Inc.
InventorsPhilippe H. Gow, Robert A. Rogers, Andrea L. Lijoi
Life of this patent
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Abstract
An apparatus for monitoring a battery pack having a plurality of serially connected rechargeable batteries. The apparatus comprises a means of detecting cell reversal and a means of protecting the batteries of the battery pack upon detection of cell reversal.
Claims17
An apparatus for monitoring a battery pack having two or more serially connected rechargeable batteries, said battery pack divided into N serially connected battery segments (S.sub.1 . . . S.sub.N) where N is an integer greater than or equal to one, each of said battery segments (S.sub.1 . . . S.sub.N) having two or more of said serially connected rechargeable batteries, said apparatus comprising:
- a detection means for detecting cell reversal in said battery pack, said detection means comprising:
- N divider networks (D.sub.1 . . . D.sub.N), each including a first divider resistor serially connected to a second divider resistor at a resistor junction, each of said divider networks (D.sub.1 . . . D.sub.N) connected across the respective of said battery segments (S.sub.1 . . . S.sub.N);
- N test points (P.sub.1 . . . P.sub.N) each located at a junction between two of said rechargeable batteries within the respective of said battery segments (S.sub.1 . . . S.sub.N);
- a voltage comparison means for comparing voltage at each of said test points (P.sub.1 . . . P.sub.N) to voltage at said resistor junction of the respective of said divider networks (D.sub.1 . . . D.sub.N);
- and
- N voltage drop devices (VD.sub.1 . . . VD.sub.N), each serially connected between said first divider resistor and said second divider resistor of the respective of said divider networks (D.sub.1 . . . D.sub.N), wherein said voltage comparison means compares voltage at each of said test points (P.sub.1 . . . P.sub.N) to a voltage window defined by voltage at opposite terminals of the respective of said voltage drop devices (VD.sub.1 . . . VD.sub.N), said voltage comparison means providing a detection signal when voltage at any one of said test points (P.sub.1 . . . P.sub.N) is outside said voltage window of the respective of said voltage drop devices (VD.sub.1 . . . VD.sub.N).
An apparatus for monitoring a battery pack having a plurality of serially connected rechargeable batteries, a positive battery pack terminal, and a negative battery pack terminal, said apparatus comprising:
- a detection means for detecting cell reversal in said battery pack, said detection means comprising:
- N test points (P.sub.1 . . . P.sub.N) each located at a unique junction between two of said batteries of said battery pack, N being an integer greater than or equal to one, said test points (P.sub.1 . . . P.sub.N) sequentially ordered from high to low voltage;
- a divider network including N+1 serially connected divider resistors (DR.sub.1 . . . DR.sub.N+1), said divider resistors (DR.sub.1 . . . DR.sub.N+1) forming N resistor junctions (J.sub.1 . . . J.sub.N) where each of said resistor junctions (J.sub.1 . . . J.sub.N) is between the respective of said divider resistors (DR.sub.1 . . . DR.sub.N+1) and the next of said divider resistors (DR.sub.1 . . . DR.sub.N+1), said divider network connected across said battery pack wherein first of said divider resistors (DR.sub.1 . . . DR.sub.N+1) is connected to said positive battery pack terminal, and last of said divider resistors (DR.sub.1 . . . DR.sub.N+1) is connected to said negative battery pack terminal;
- a voltage comparison means for comparing voltage at each of said test points (P.sub.1 . . . P.sub.N) to voltage at the respective of said resistor junctions (J.sub.1 . . . J.sub.N);
- and
- N voltage drop devices (VD.sub.1 . . . VD.sub.N) each serially connected between the respective of said divider resistors (DR.sub.1 . . . DR.sub.N+1) and the next of said divider resistors (DR.sub.1 . . . DR.sub.N+1), said voltage comparison means compares voltage at each of said test points (P.sub.1 . . . P.sub.N) to a voltage window defined by voltage at opposite terminals of the respective of said voltage drop devices (VD.sub.1 . . . VD.sub.N).
A method of detecting cell reversal in a battery pack having two or more serially connected rechargeable batteries, said method comprising the steps of:
- dividing said battery pack into N serially connected battery segments (S.sub.1 . . . S.sub.N) wherein N is an integer greater than or equal to one, each of said battery segments including two or more of said serially connected rechargeable batteries;
- connecting each of N divider networks (D.sub.1 . . . D.sub.N) across the respective of said battery segments (S.sub.1 . . . S.sub.N), each of said divider networks (D.sub.1 . . . D.sub.N) including a first divider resistor serially connected to a second divider resistor through a voltage drop device;
- locating each of N test points (P.sub.1 . . . P.sub.N) at a junction between two of said rechargeable batteries within the respective of said battery segments (S.sub.1 . . . S.sub.N);
- comparing voltage at each of said test points (P.sub.1 . . . P.sub.N) to a voltage window defined by voltage at opposite terminals of said voltage drop device of the respective of said divider networks (D.sub.1 . . . D.sub.N);
- and
- providing a detection signal when voltage at any one of said test points (P.sub.1 . . . P.sub.N) is outside said voltage window across said voltage drop device of the respective of said divider networks (D.sub.1 . . . D.sub.N).
Dependencies are inferred from the claim text.