Methods and apparatus for reporting a relative state of charge of a battery
Various embodiments of the present technology may comprise methods and apparatus to determine an RSOC value of a battery. The methods and apparatus may comprise utilizing various parameters, such as voltage, current, and/or temperature to calculate the RSOC of the battery. In various embodiments, the methods and apparatus may display one of an actual RSOC and a reported RSOC. In various embodiments, the methods and apparatus may further detect changes in the relevant parameter(s), adjust the reported RSOC of the battery accordingly, and report the adjusted RSOC.
1. An apparatus for determining an RSOC of a battery, comprising:
a current sensor responsive to a current through the battery;
a temperature sensor responsive a temperature of the battery; and
a logic unit responsive to the current sensor and the temperature sensor, wherein the logic unit:
determines a direction of change of the temperature of the battery according to the temperature sensor;
determines a charging mode of the battery according to the current sensor; and
selects one of an actual RSOC value or a previously-reported RSOC value according to the direction of change of the temperature of the battery and the charging mode of the battery.
2. The apparatus of claim 1 , wherein the logic unit selects the previously-reported RSOC if the charging mode of the battery is charging and the temperature of the battery is increasing.
3. The apparatus of claim 1 , wherein the logic unit selects the actual RSOC if the charging mode of the battery is charging and the temperature of the battery is decreasing.
4. The apparatus of claim 1 , wherein the logic unit selects the previously-reported RSOC if the charging mode of the battery is discharging and the temperature of the battery is decreasing.
5. The apparatus of claim 1 , wherein the logic unit selects the actual RSOC if the charging mode of the battery is discharging and the temperature of the battery increasing.
6. A method for determining an RSOC value of a battery, comprising:
determining a mode of operation of the battery, wherein the mode of operation of battery is at least one of a charging mode and a discharging mode;
measuring a first temperature;
measuring a second temperature;
computing an RSOC;
comparing the first to the second temperature to determine a temperature change; and
selecting one of an actual RSOC value or a reported RSOC value based on the temperature change.
7. The method of claim 6 , wherein determining the mode of operation of the battery comprises detecting a direction of current flow.
8. The method of claim 6 , wherein measuring the first and second temperature comprises utilizing a thermistor and converting a thermistor voltage to a temperature value.
9. The method of claim 6 , wherein the reported RSOC is selected if the mode of operation of the battery is the charging mode and the second temperature is greater than the first temperature.
10. The method of claim 6 , wherein the actual RSOC is selected if the mode of operation of the battery is the charging mode and the second temperature is less than or equal to the first temperature.
11. The method of claim 6 , wherein the reported RSOC is selected if the mode of operation of the battery is the discharging mode and the second temperature is less than the first temperature.
12. The method of claim 6 , wherein the actual RSOC is selected if the mode of operation of the battery is the discharging mode and the second temperature is greater than or equal to the first temperature.
13. The method of claim 6 , further comprising detecting a change in the mode of operation of the battery, wherein the change in the mode of operation, comprises one of the charging mode to the discharging mode or the discharging mode to the charging mode.
14. The method of claim 13 , wherein if the battery mode of operation changes from the charging mode to the discharging mode, and the actual RSOC value is less than the reported RSOC value, then the reported RSOC is adjusted to equal the actual RSOC.
15. The method of claim 13 , wherein if the battery mode of operation changes from the discharging mode to the charging mode, and the actual RSOC value is greater than the reported RSOC value, then the reported RSOC is adjusted to equal the actual RSOC.
16. A system for determining an RSOC of a battery, comprising:
a battery pack comprising the battery and a temperature measurement device to measure a first voltage representing a first temperature, and second voltage representing a second temperature of the battery;
a fuel gauge system coupled to the battery pack, comprising:
a logic unit;
a memory device coupled to the logic unit, comprising a look-up table with predetermined data associating a voltage with a temperature;
a current sensor, coupled to the logic unit, to determine a state of the battery, wherein the state of battery is at least one of charging and discharging;
wherein the logic unit:
compares the first and second temperatures;
determines a mode change of the state of the battery; and
selects one of an actual RSOC value or a reported RSOC value; and
a display unit coupled to the fuel gauge system to display the selected RSOC.
17. The system according to claim 16 , wherein the logic unit selects the reported RSOC if the state of the battery is charging and the second temperature is greater than the first temperature.
18. The system of claim 16 , wherein the logic unit selects the actual RSOC if the state of the battery is charging and the second temperature is less than or equal to the first temperature.
19. The system of claim 16 , wherein the logic unit selects the reported RSOC if the state of the battery is discharging and the second temperature is less than the first temperature.
20. The system of claim 16 , wherein the logic unit selects the actual RSOC if the state of the battery is discharging and the second temperature is greater than or equal to the first temperature.