Systems and methods of battery cell anomaly detection

1. A system comprising:

a plurality of voltage to current (V-to-I) converters each being couplable to one of a respective plurality of cells;

a cell detector circuit coupled to each of the plurality of V-to-I converters to receive a current generated by its respective V-to-I converter, wherein the cell detector circuit compares each of the respective plurality of cells with other cells in the plurality of cells by determining a maximum current input to the converters and which cell provides that maximum current to determine if any of the plurality of V-to-I converters provides an anomalous input current and determines which of the plurality of V-to-I converters provides the anomalous input current whereby relative performance between the cells is determined, wherein the cell detector circuit further comprises a plurality of multi-input current detectors, wherein each of the plurality of multi-input current detectors is coupled to each of the plurality of V-to-I converters, and wherein each multi-input current detector compares at least one of the V-to-I converter outputs to a threshold value to determine an anomalous current; and wherein each multi-input detector outputs a logic signal for each of the inputs, each output of the multi-input current detector is coupled to the input of an OR gate.

2. The system of claim 1 , wherein at least one of the V-to-I converters comprises a plurality of field effect transistors, bipolar transistors, CMOS transistors, or current mirror devices.

3. The system of claim 1 , wherein for each multi-input current detector, one input of each V-to-I converter is amplified.

4. The system of claim 1 , wherein for each multi-input current detector, one input of each V-to-I converter is not amplified.

5. The system of claim 1 , wherein the cell detector circuit is ground referenced.

6. A battery pack comprising:

a plurality of cells;

a plurality of high-value resistor dividers, each high-value resistor divider coupled across one cell of the plurality of cells;

a plurality of multi-input current detectors, each multi-input current detector coupled to at least one of a plurality of dividers for one cell of the plurality of cells, the multi-input current detector determining the maximum current input to the detectors and which cell provides maximum current and including a current comparator which compares each of the plurality of cells with other cells in the plurality of cells,

wherein each of the plurality of multi-input current detectors is coupled to each of the plurality of V-to-I converters, and wherein each multi-input current detector compares at least one of the V-to-I converter outputs to a threshold value to determine an anomalous current; and wherein each multi-input detector outputs a logic signal for each of the inputs, each logic signal being coupled to the input of an OR gate for

determining which cell of the plurality of cells is in a fault condition.

7. The battery pack of claim 6 , wherein the battery pack further comprises a plurality of voltage to current (V-to-I) converters, wherein each of the plurality of V-to-I converters converts the voltage to a representative current.

8. The battery pack of claim 7 , wherein at least one of the V-to-I converters comprises a plurality of field effect transistors, bipolar transistors, CMOS transistors, or current mirror devices.

9. The battery pack of claim 6 , wherein for each multi-input current detector one input of each V-to-I converter is amplified.

10. The battery pack of claim 6 , wherein for each multi-input current detector, one input of each V-to-I converter is not amplified.

11. The battery pack of claim 6 , wherein the fault condition indicates an input resistance greater than a predetermined input resistance.

12. The battery pack of claim 6 , wherein at least one of the plurality of multi-input current detectors is ground referenced.

13. A method comprising:

receiving voltages across the cells of a plurality of cells of a battery pack;

converting the received voltages to currents;

data processing the currents to compare each of the plurality of cells with other cells in the plurality of cells by

amplifying one of the currents;

comparing each of the currents to a predetermined reference current;

producing a logic level signal for each current based on the comparing; and

inverting the logic level signal for the current that was amplified;

determining a maximum current input to the converters and which cell provides that maximum current to determine whether at least one of the currents is anomalous; and

reporting the at least one anomalous current as indicative meeting a failure criterion.

14. The method of claim 13 , wherein the method further comprises the step of determining if any of the inverted logic level signals indicate an anomalous cell voltage.

15. The method of claim 13 , wherein the step of data processing the currents is performed using a ground referenced circuit.

16. A method comprising:

receiving voltages across the cells of a plurality of cells of a battery pack;

converting the received voltages to currents;

data processing the currents to compare each of the plurality of cells with other cells in the plurality of cells;

determining a maximum current input to the converters and which cell provides that maximum current to determine whether at least one of the currents is anomalous; and

reporting the at least one anomalous current as indicative meeting a failure criterion, wherein the step of data processing the currents further comprises:

amplifying all but one of the currents;

comparing each of the currents to a predetermined reference current;

producing a logic level signal for each current based on the comparing; and

inverting the logic level signal for the current that was not amplified.

17. The method of claim 16 , wherein the method further comprises the step of determining if any of the inverted logic level signals indicate an anomalous cell voltage.