DETECTING INTERNAL SHORT CIRCUITS IN BATTERIES
First Claim
1. A system, comprising:
- a plurality of cells coupled in series to power a load;
a battery management system configured to;
identify a flagged cell of the plurality of cells that has an electrical parameter different from another cell of the plurality of cells;
simulate a cell model representing one of the plurality of cells; and
change a value of a simulated surrogate resistor until a voltage across the cell model equals a voltage across the flagged cell, wherein the value of the simulated surrogate resistor is assigned as a value of an internal resistance of the flagged cell.
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Abstract
A battery management system (BMS) described herein determines the internal resistance for a cell that may have an internal short circuit. In one aspect, the BMS monitors the voltage across each of a plurality cells that are coupled in series. If the voltage across one of the cells differs from the voltages across the other cells, the BMS can flag the cell as potentially having an internal short circuit. Once flagged, the BMS can use a simulator that stores a model cell that has similar characteristics as the cells monitored by the BMS to determine the internal resistance of the flagged cell. In one aspect, the simulator changes the value of a surrogate resistor that is parallel with the model cell until the voltage across the model cell matches the voltage of the flagged cell. The value of the surrogate resistor indicates the internal resistance of the flagged cell.
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Citations
21 Claims
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1. A system, comprising:
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a plurality of cells coupled in series to power a load; a battery management system configured to; identify a flagged cell of the plurality of cells that has an electrical parameter different from another cell of the plurality of cells; simulate a cell model representing one of the plurality of cells; and change a value of a simulated surrogate resistor until a voltage across the cell model equals a voltage across the flagged cell, wherein the value of the simulated surrogate resistor is assigned as a value of an internal resistance of the flagged cell. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computing system, comprising:
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at least one computer processor; and a memory storing a program, wherein, when executed by the computer processor, the program is configured to perform an operation comprising; identifying a flagged cell of a plurality of cells that has an electrical parameter different from another cell of the plurality of cells, wherein the plurality of cells are coupled in series to power a load; simulating a cell model representing one of the plurality of cells; and changing a value of a simulated surrogate resistor until a voltage across the cell model equals a voltage across the flagged cell, wherein the value of the simulated surrogate resistor is assigned as a value of an internal resistance of the flagged cell. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for monitoring a plurality of cells of a battery coupled in series to power a load, the method comprising:
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identifying a flagged cell of the plurality of cells that has an electrical parameter different from another cell of the plurality of cells; simulating, using one or more processors, a cell model representing one of the plurality of cells; and changing a value of a simulated surrogate resistor until a voltage across the cell model equals a voltage across the flagged cell, wherein the value of the simulated surrogate resistor is assigned as a value of an internal resistance of the flagged cell. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A system, comprising:
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a plurality of cells coupled in series to power a load; a spare cell selectively coupled to the plurality of cells; a battery management system configured to; identify a flagged cell of the plurality of cells that has a charge imbalance relative to another cell of the plurality of cells; enable the spare cell to compensate for the charge imbalance on the flagged cell during at least one of a charge cycle or discharge cycle; determine total energy stored in, or drained from, the spare cell during the at least one charge cycle of discharge cycle; and determine an internal resistance of the flagged cell using the total energy.
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Specification