Real time active multi-cell balancing

1. A computer-implemented system for balancing battery cells of a multi-cell battery having a plurality of battery cells, the computer-implemented system comprising:

a processor configured to:

determine a state of charge for each battery cell;

generate a probability table for the plurality of battery cells, the probability table having probabilities based on a deviation from a mean state of charge for each battery cell;

select one of the battery cells via probabilistic selection according to the probabilities;

generate an instruction for adjusting a charge of the selected battery cell; and

transmit the instruction such that the charge of the selected battery cell is adjusted.

2. The computer-implemented system of claim 1 , wherein the probability table is a normalized cumulative probability table.

3. The computer-implemented system of claim 1 , wherein determining a state of charge for each battery cell is performed over approximately one percent of a total battery discharge time.

4. The computer-implemented system of claim 1 , wherein the probability table includes a selectable dummy battery cell having a fixed deviation from the mean state of charge such that a probability of selecting the dummy battery cell is higher if the battery cells are more balanced than if the battery cells are less balanced, the processor being configured to not generate a battery cell adjustment instruction if the dummy battery cell is selected so as to prevent unnecessary small deviation balancing.

5. The computer-implemented system of claim 1 , wherein the processor is configured to simultaneously a) select the battery cell and generate the battery cell adjustment instruction and b) determine the state of charge for each battery cell and generate the probability table for all of the battery cells.

6. The computer-implemented system of claim 5 , wherein the processor is configured to update probabilities in the probability table and select battery cells at a one-to-one rate.

7. The computer-implemented system of claim 1 , wherein adjusting the charge of the selected battery cell includes moving charge from another battery cell to the selected battery cell.

8. The computer-implemented system of claim 1 , wherein the processor is configured to select the battery cell and generate the battery cell adjustment instruction in approximately 10 microseconds.

9. A method of balancing battery cells of a multi-cell battery, the method comprising the steps of:

determining a state of charge for each battery cell;

generating a probability table for the battery cells, the probability table having probabilities based on a deviation from a mean state of charge for each battery cell;

selecting one of the battery cells via probabilistic selection according to the probabilities;

generating an instruction for adjusting a charge of the selected battery cell; and

transmitting the instruction such that the charge of the selected battery cell is adjusted.

10. The computer-implemented method of claim 9 , wherein the probability table is a normalized cumulative probability table.

11. The computer-implemented method of claim 9 , wherein the step of determining a state of charge for each battery cell is performed over approximately one percent of a total battery discharge time.

12. The computer-implemented method of claim 9 , wherein the probability table includes data representative of a selectable dummy battery cell having a fixed deviation from the mean state of charge such that a probability of selecting the dummy battery cell increases as the battery cells become more balanced so as to prevent unnecessary small deviation balancing, the charge adjusting instruction not being generated if the dummy battery cell is selected.

13. The computer-implemented method of claim 9 , wherein the processor is configured to simultaneously a) select the battery cell and generate the battery cell adjustment instruction and b) determine the state of charge for each battery cell and generate the probability table for all of the battery cells.

14. The computer-implemented method of claim 13 , wherein the processor is configured to update probabilities in the probability table and select battery cells at a one-to-one rate.

15. The computer-implemented method of claim 9 , wherein adjusting the charge of the selected battery cell includes moving charge from another battery cell to the selected battery cell.

16. A method of balancing battery cells of a lithium or lithium-ion multi-cell battery during charging or discharging of the multi-cell battery, the method comprising the steps of:

determining a state of charge for each battery cell;

generating a normalized cumulative probability table for all of the battery cells plus a selectable dummy battery cell having a fixed deviation from a mean state of charge, the steps of determining the states of charge and generating the normalized cumulative probability table being performed over approximately one percent of a total battery charge or discharge time;

selecting one of the battery cells or the dummy battery cell via probabilistic selection according to the probability table, the probability of selecting the dummy battery cell being higher if the battery cells are more balanced than if the battery cells are less balanced so as to prevent unnecessary small deviation balancing;

generating an instruction for adjusting a charge of the selected battery cell if the dummy battery cell is not selected, the steps of selecting the battery cell and generating the charge adjustment instruction being performed over approximately 10 milliseconds; and

transmitting the instruction such that the charge of the selected battery cell is adjusted if the dummy battery cell is not selected.