Battery sensing circuit path resistance compensation systems and methods
View Patent ↗System and methods for measuring parameters of a battery system using a battery sensing circuit are presented. In certain embodiments, the systems and methods allow a vehicle battery sensing circuit and/or other associated system to measure a compensation parameter. The compensation parameter may be utilized by the battery sensing circuit and/or other associated system in measuring other parameters relating to the battery system including cell voltages.
1. A method for measuring an actual voltage of a first cell included in a battery stack, the method comprising:
measuring a first voltage of the first cell with a first balancing switch associated with the first cell turned off and a second balancing switch associated with a second cell included in the battery stack turned off;
measuring a second voltage of the first cell with the first and second balancing switches turned on;
determining a compensation parameter based on the measured first and second voltages; and
determining the actual voltage of the first cell based on the compensation parameter and at least one of the first and second voltages.
2. The method of claim 1 , wherein the first cell and the second cell comprise adjacent cells in the battery stack.
3. The method of claim 1 , wherein the compensation parameter is further determined based on a predetermined current associated with a current through the first balancing switch when the first and second balancing switches are turned on.
4. The method of claim 1 , wherein the actual voltage of the first cell is further determined based on measurement current of a battery sensing system through a sensing path associated with the first cell.
5. The method of claim 1 , wherein the compensation parameter comprises a resistance of a sensing path associated with the first cell.
6. The method of claim 5 , wherein the compensation parameter is determined according to:
R
=
V
OFF
-
V
ON
I
BAL
where R comprises the compensation parameter, V OFF comprises the first voltage, V ON comprises the second voltage, and I BAL comprises a predetermined current associated with a current through the first balancing switch with the first and second balancing switches are turned on.
7. The method of claim 6 , the actual voltage is determined according to:
V ACTUAL =I TOT *R−V OFF
where V ACTUAL comprises the actual voltage, I TOT comprises a predetermined current through a sensing path associated with the first cell, R comprises the compensation parameter, and V OFF comprises the first voltage.
8. A system comprising:
a battery stack comprising a first cell;
a first balancing switch coupled to the first cell; and
a battery sensing circuit coupled to the first cell by a first sense path;
wherein the battery sensing circuit is configured to:
measure a first voltage of the first cell with the first balancing switch and a second balancing switch associated with a second cell included in the battery stack turned off;
measure a second voltage of the first cell with the first and second balancing switches turned on;
determine a compensation parameter based on the measured first and second voltages; and
determine the actual voltage of the first cell based on the compensation parameter and at least one of the first and second voltages.
9. The system of claim 8 , wherein the first cell and the second cell comprise adjacent cells in the battery stack.
10. The system of claim 8 , wherein the battery sensing circuit is further configured to determine the compensation parameter based on a predetermined current associated with a current through the first balancing switch when the first and second balancing switches are turned on.
11. The system of claim 8 , wherein battery sensing circuit is further configured to determine the actual voltage of the first cell based on measurement current of a battery sensing system through a sensing path associated with the first cell.
12. The system of claim 8 , wherein the compensation parameter comprises a resistance of the first sense path.
13. The system of claim 12 , wherein the compensation parameter is determined according to:
R
=
V
OFF
-
V
ON
I
BAL
where R comprises the compensation parameter, V OFF comprises the first voltage, V ON comprises the second voltage, and I BAL comprises a predetermined current associated with a current through the first balancing switch with the first and second balancing switches are turned on.
14. The system of claim 13 , the actual voltage is determined according to:
V ACTUAL =I TOT *R−V OFF
where V ACTUAL comprises the actual voltage, I TOT comprises a predetermined current through a sensing path associated with the first cell, R comprises the compensation parameter, and V OFF comprises the first voltage.
15. A non-transitory computer readable storage medium storing instructions that, when executed by a processor, cause the processor to perform a method comprising:
receiving a first voltage measurement of a first cell included in a battery stack with a first balancing switch associated with the first cell turned off and a second balancing switch associated with a second cell included in the battery stack turned off;
receiving a second voltage measurement of the first cell with the first and second balancing switches turned on;
determining a compensation parameter based on the first and second voltage measurements; and
determining the actual voltage of the first cell based on the compensation parameter and at least one of the first and second voltage measurements.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the first cell and the second cell comprise adjacent cells in the battery stack.
17. The non-transitory computer-readable storage medium of claim 15 , wherein the compensation parameter is further determined based on a predetermined current associated with a current through the first balancing switch when the first and second balancing switches are turned on.
18. The non-transitory computer-readable storage medium of claim 15 , wherein the actual voltage of the first cell is further determined based on measurement current of a battery sensing system through a sensing path associated with the first cell.
19. The non-transitory computer-readable storage medium of claim 15 , wherein the compensation parameter comprises a resistance of a sensing path associated with the first cell.