Monitoring system and method
View Patent ↗A method and system for monitoring a voltage of a battery cell or a battery stack. A first monitoring unit has a first plurality of battery monitoring nodes, first and second data ports, a first supply port switchably coupled to the first plurality of battery monitoring nodes, a second supply port switchably coupled to the first plurality of battery monitoring nodes, and a third supply port. A controller is connected to the first monitoring unit. Alternatively, a reference voltage may be connected to the controller or it may be connected to the first monitoring unit.
1. A method for monitoring one or more batteries, comprising:
measuring a voltage of a first cell of a first battery using a first monitoring unit to generate a first measurement result, wherein measuring the voltage of the first cell of the first battery includes using a first reference voltage and simultaneously inputting the first reference voltage and a voltage generated in response to the voltage of the first cell into a first analog-to-digital (A/D) converter;
measuring the first reference voltage using a controller to generate a second measurement result, wherein measuring the first reference voltage includes using a precise external reference voltage and simultaneously inputting the external reference voltage and a voltage generated in response to the first reference voltage into a second A/D converter, the second A/D converter in the controller; and
using the first measurement result and the second measurement result to calculate a first correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
2. The method of claim 1 , further including:
measuring a voltage of a second cell of the first battery using the first monitoring unit, wherein measuring the voltage of the second cell includes using the first reference voltage; and
using the first correction factor to correct the measurement of the voltage of the second cell.
3. The method of claim 1 , further including:
measuring voltages of a plurality of additional cells of the first battery using the first monitoring unit, wherein measuring the voltages of the plurality of additional cells includes using the first reference voltage; and
using the first correction factor to correct the measurements of the voltages of the plurality of cells.
4. The method of claim 1 , further including:
measuring a voltage of a first cell of a second battery using a second monitoring unit to generate a third measurement result, wherein measuring the voltage of the first cell of the second battery includes using a second reference voltage;
measuring the second reference voltage using the first monitoring unit to generate a fourth measurement result; and
using the third measurement result and the fourth measurement result to calculate a second correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
5. The method of claim 4 , further including using the first and second correction factors to correct the set of measurements from at least one of the first and second monitoring units.
6. The method of claim 4 , further including configuring at least one of the first and second monitoring units to measure a voltage across the first cell or a group of cells.
7. The method of claim 6 , further including providing a first selectable input port for coupling to an adjacent monitoring unit and that is capable of measuring a voltage that is a function of the reference voltage of the adjacent monitoring unit and providing a second selectable input port for measuring a voltage of an external reference voltage.
8. The method of claim 4 , further including using the controller to calculate the first and second correction factors.
9. The method of claim 4 , further including: coupling the controller to at least one of the first and second monitoring units.
10. The method of claim 4 , further including:
coupling the controller to at least one of the first and second monitoring units;
coupling the first reference voltage to the first monitoring unit; and
coupling the second reference voltage to the second monitoring unit.
11. The method of claim 1 , further including:
measuring a first voltage at a first node in the first monitoring unit;
measuring a second voltage at a second node in a second monitoring unit;
using the first voltage at the first node and the second voltage at the second node to calculate a second correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
12. A method for monitoring one or more batteries, comprising:
configuring at least one of a first monitoring unit and a second monitoring unit to measure a voltage across a first cell or a group of cells;
providing a selectable input port to at least one of the first and second monitoring units, the selectable input port for coupling to a controller, the controller adjacent to at least one of the first and second monitoring units;
measuring a voltage of the first cell of a first battery using the first monitoring unit to generate a first measurement result, wherein measuring the voltage of the first cell of the first battery includes using a first reference voltage and simultaneously inputting the first reference voltage and a voltage generated in response to the measured voltage of the first cell into a first analog-to-digital (A/D) converter;
measuring the first reference voltage using the controller to generate a second measurement result, wherein measuring the first reference voltage includes using a precise external reference voltage and simultaneously inputting the external reference voltage and a voltage generated in response to the first reference voltage into a second A/D converter, the second A/D converter in the controller; and
using the first measurement result and the second measurement result to calculate a first correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
13. The method of claim 12 , further including:
measuring a voltage of a second cell of the first battery using the first monitoring unit, wherein measuring the voltage of the second cell includes using the first reference voltage; and
using the first correction factor to correct the measurement of the voltage of the second cell.
14. The method of claim 12 , further including:
measuring voltages of a plurality of additional cells of the first battery using the first monitoring unit, wherein measuring the voltages of the plurality of additional cells includes using the first reference voltage; and
using the first correction factor to correct the measurements of the voltages of the plurality of cells.
15. The method of claim 12 , further including:
measuring a voltage of a first cell of a second battery using the second monitoring unit to generate a third measurement result, wherein measuring the voltage of the first cell of the second battery includes using a second reference voltage;
measuring the second reference voltage using the first monitoring unit to generate a fourth measurement result; and
using the third measurement result and the fourth measurement result to calculate a second correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
16. A method for monitoring one or more batteries, comprising:
coupling a controller to at least one of a first monitoring unit and a second monitoring unit;
coupling a first reference voltage of the first monitoring unit to a selectable port to measure a voltage of the first reference voltage;
measuring a voltage of a first cell of a first battery using the first monitoring unit to generate a first measurement result, wherein measuring the voltage of the first cell of the first battery includes using the first reference voltage and simultaneously inputting the first reference voltage and a voltage generated in response to the measured voltage of the first cell into a first analog-to-digital (A/D) converter;
measuring the first reference voltage using the second monitoring unit to generate a second measurement result, wherein measuring the first reference voltage includes using a precise external reference voltage, and simultaneously inputting the external reference voltage and a voltage generated in response to the measured first reference voltage into a second A/D converter in the second monitoring unit; and
using the first measurement result and the second measurement result to calculate a first correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.
17. The method of claim 16 , further including using the controller to calculate the first correction factor.
18. The method of claim 16 , further including:
measuring a voltage of a second cell of the first battery using the first monitoring unit, wherein measuring the voltage of the second cell includes using the first reference voltage; and
using the first correction factor to correct the measurement of the voltage of the second cell.
19. The method of claim 16 , further including:
measuring voltages of a plurality of additional cells of the first battery using the first monitoring unit, wherein measuring the voltages of the plurality of additional cells includes using the first reference voltage; and
using the first correction factor to correct the measurements of the voltages of the plurality of cells.
20. The method of claim 16 , further including:
measuring a voltage of a first cell of a second battery using the second monitoring unit to generate a third measurement result, wherein measuring the voltage of the first cell of the second battery includes using a second reference voltage;
measuring the second reference voltage using the first monitoring unit to generate a fourth measurement result; and
using the third measurement result and the fourth measurement result to calculate a second correction factor suitable for use in correcting a set of measurements from at least one of the first and second monitoring units.