TWI403750B - Battery capacity calculating method and device thereof - Google Patents

Abstract

The invention relates to a cell capacity caculating method, which reads a present reference capacity of a cell, and converses the reference capacity to a corresponding voltage, obtains the present voltage of the cell, accumulates the times that the voltage is continuously smaller or larger than the reference voltage, when the time that the voltage continuously smaller than the reference voltage reaches a predetermined value, the reference capacity is adjusted to a lower value according to a ratio, and when the time that the voltage continuously larger than the reference voltage reaches a predetermined value, the reference capacity is adjusted to a larger value according to a ratio. Thereby, the capacity is not changed with the change of the voltage, and the capacity value is stable and correct.

Description

Battery capacity calculation method and battery capacity calculation device

The invention relates to a method for calculating electric quantity, in particular to a method for calculating battery capacity and a device thereof.

At present, the battery capacity performance method usually uses a voltage-capacity comparison table to convert the voltage into a corresponding percentage of the capacitance, but this practice often has a problem of insufficient capacitance accuracy. The reason is that the battery voltage (vertical axis) and the capacitance (horizontal axis) are as shown in the comparison diagram of Fig. 1. When the load of the system is different, the discharge current of the battery will be different, so that the voltage-capacitance discharge in Fig. 1 corresponds to The curves are different, and when the battery is charged at different currents, the voltage-capacity charging corresponding curve is different, so that the same battery voltage is under different system load or charging current, and the corresponding battery capacity There are obvious differences, especially the battery's capacitance and voltage are nonlinear. A small voltage change will cause a large error in the capacitance. Therefore, if the voltage-capacity comparison table is used, the capacitance will follow. The voltage fluctuates up and down, causing the system to fail to display accurate battery capacity.

Accordingly, it is an object of the present invention to provide a battery capacity calculation method and apparatus thereof that can accurately present battery capacity.

To achieve the above objective, the battery capacity calculation method of the present invention comprises: reading a current reference capacity of the battery, the reference capacitance corresponding to a reference voltage; obtaining a current voltage value of the battery; determining whether the voltage value crosses the reference a voltage; when determining that the voltage value crosses the reference voltage, accumulating the number of times the voltage value crosses the reference voltage; and when determining that the cumulative value of the voltage value across the reference voltage reaches a preset value, adjusting the ratio according to a certain ratio Reference capacitance.

Preferably, the step of determining whether the voltage value crosses the reference voltage comprises: determining whether the voltage value is less than the reference voltage; and when determining that the voltage value crosses the reference voltage, accumulating the number of times the voltage value crosses the reference voltage The step includes: when it is determined that the voltage value is less than the reference voltage, accumulating the number of times the voltage value is less than the reference voltage.

Preferably, the step of determining whether the voltage value crosses the reference voltage comprises: determining whether the voltage value is greater than the reference voltage; and when determining that the voltage value crosses the reference voltage, accumulating the number of times the voltage value crosses the reference voltage The step of: including when the voltage value is greater than the reference voltage, accumulating the number of times the voltage value is greater than the reference voltage.

Preferably, when it is determined that the voltage value is greater than the reference voltage, the cumulative value of the voltage value less than the reference voltage is reset to zero. When the voltage value is determined to be less than the reference voltage, the voltage value is greater than the cumulative value of the reference voltage. The number of times is zero.

Preferably, when the reference capacitance is adjusted downward according to a certain ratio, the cumulative value of the voltage value less than the reference voltage is reset to zero; and when the reference capacitance is adjusted upward according to a certain ratio, the voltage value is greater than the The cumulative number of reference voltages is zeroed.

A battery capacity calculation device for implementing the above method, for calculating a battery capacity, the device comprising: a battery capacity reading unit, reading a current reference capacity of the battery, and converting the reference capacitance into Corresponding a reference voltage; a battery voltage determining unit reads a current voltage value of the battery, and determines whether the voltage value crosses the reference voltage, and when determining that the voltage value crosses the reference voltage, accumulating the voltage value across the The number of times of the reference voltage; and a battery capacity adjustment unit, when it is determined that the cumulative number of times the voltage value crosses the reference voltage reaches a predetermined value, the reference capacitance is adjusted according to a certain ratio.

Preferably, the battery voltage determining unit determines whether the voltage value is less than the reference voltage, and when determining that the voltage value is less than the reference voltage, accumulating the number of times the voltage value is less than the reference voltage.

Preferably, the battery voltage determining unit determines whether the voltage value is greater than the reference voltage, and when determining that the voltage value is greater than the reference voltage, accumulating the number of times the voltage value is greater than the reference voltage.

Preferably, the battery voltage determination unit determines that the voltage value is greater than the reference voltage, and then zeros the accumulated value of the voltage value less than the reference voltage; and the battery voltage determination unit determines that the voltage value is less than the reference voltage, The cumulative value of the voltage value greater than the reference voltage is zeroed.

Preferably, after the battery capacity adjustment unit adjusts the reference capacitance downward according to a certain ratio, the cumulative value of the voltage value less than the reference voltage is reset to zero; and the battery capacity adjustment unit adjusts the reference capacitance upward according to a certain ratio. Thereafter, the cumulative value of the voltage value greater than the reference voltage is reset to zero.

The utility model has the advantages that the battery voltage judging unit compares the obtained battery voltage with the reference voltage converted by the current reference capacity for multiple times, and determines that the battery voltage is in a downward or rising trend, and is determined by the battery capacity adjusting unit. Adjusting the capacitance downward or upward can control the battery capacity to be fluctuated without fluctuation of the voltage value, so that the capacitance can stably and accurately reflect the voltage value of the battery.

The foregoing and other objects, features, and advantages of the invention are set forth in the <RTIgt;

Referring to FIG. 2, it is a first embodiment of the battery capacity calculation device of the present invention, which is used to implement the battery capacity calculation method of the present invention as shown in FIG. 3, and the present embodiment is applied in the process of discharging a battery.

The battery capacity calculation device 2 can be disposed in any portable electronic device, such as a notebook computer, a mobile phone, a personal digital assistant, a mobile navigation device, an iPAD, or the like, or can be applied to a separate power supply system, a battery charger. Or in an electrical energy storage device that uses a battery as a power storage medium to calculate the capacitance of the battery therein.

The battery capacity calculation device 2 includes a battery capacity reading unit 21, a battery voltage determination unit 22, and a battery capacity adjustment unit 23, and the three units 21, 22, and 23 can be implemented in a soft body, a hardware, or a firmware. .

As shown in step 31 of FIG. 3, the battery capacity reading unit 21 is configured to read a current reference capacity of the battery and convert the reference capacitance into a corresponding reference voltage. As shown in step 32 of FIG. 3, the battery voltage determining unit 22 obtains a current voltage value of the battery, and performs step 33 to determine whether the voltage value is less than the reference voltage. If yes, step 34 is performed, and the accumulated voltage value is less than the reference voltage. Then, step 35 is performed to determine whether the cumulative value of the voltage value is less than a predetermined value of the reference voltage, and if so, the battery capacity adjusting unit 23 performs step 36 to adjust the reference capacitance downward according to a certain ratio, and The cumulative number of times is zero.

Then, repeat steps 31-36 above. Thereby, even if the voltage of the battery changes up and down during the discharge process, the battery voltage is continuously determined through steps 32-35, and it is determined that the battery voltage is less than the reference voltage in successive multiple determinations, and it is determined that the battery voltage does decrease. Only adjust the reference capacity of the battery downwards so that the battery capacity does not change with voltage up and down, and presents stable and accurate capacitance information.

Similarly, in the second embodiment of the present invention, the battery capacity calculating device 2 described above can also calculate the capacitance of the battery during charging of the battery. When the battery is charged, as shown in step 41 of FIG. 4, the battery capacity reading unit 21 reads a current reference capacity of the battery and converts the reference capacitance into a corresponding reference voltage. As shown in step 42 of FIG. 4, the battery voltage determining unit 22 obtains a current voltage value of the battery, and performs step 43 to determine whether the voltage value is greater than the reference voltage. If yes, step 44 is performed, and the cumulative voltage value is greater than the reference voltage. Then, step 45 is performed to determine whether the cumulative number of times the voltage value is greater than the reference voltage reaches a predetermined value, and if so, the battery capacity adjusting unit 23 performs step 46 to adjust the reference capacitance downward according to a certain ratio, and The cumulative number of times is zero. Then, repeat steps 31-36 above.

Therefore, even if the voltage of the battery changes up and down during the charging process, the battery voltage is continuously determined through steps 32-35, and the accumulated battery voltage is greater than the reference voltage in successive multiple determinations, and the voltage is continuously increased. Adjusting the reference capacity of the battery upwards so that the battery capacity does not fluctuate with voltage, and presents stable and correct capacitance information.

Referring to FIG. 5, it is a third embodiment of the battery capacity calculation device of the present invention. This embodiment is applied to a notebook computer 4 as an example, and a secondary battery used in a notebook computer, that is, a lithium battery. The maximum power is about 4.2V, and the minimum power is about 3.5V. In order to display the capacitance, the power management module 41 displays the remaining voltage of the battery as a percentage of the capacitance on its display 42, for example. When the battery voltage is at the maximum power of 4.2V, the capacitance is 100%. When the battery voltage is half of 3.85V, the capacitance is 50%, and the battery voltage is 0% when the minimum voltage is 3.5V, that is, A percentage of the capacitance corresponds to a voltage of 0.007V.

Therefore, in this embodiment, when the battery is powered to the notebook computer 4, as shown in step 31 of FIG. 3, the battery capacity reading unit 21 can read the current capacity of the battery from the power management module 41 of the notebook computer 4. For example, 65% shown in FIG. 6 is used as a starting reference capacity, and the reference capacitance is converted into a corresponding reference voltage, that is, 3.952V. Then, the battery voltage determining unit 22 performs step 32, and obtains the current voltage value of the battery from the power management module 41, and proceeds to step 33 to compare whether the voltage value is less than the reference voltage 3.952V. If yes, step 34 is performed to accumulate the voltage. The value is less than the number of times of the reference voltage, and step 35 is performed to determine whether the cumulative number of times the voltage value is less than the reference voltage reaches a predetermined value (for example, 2 times), and if not, repeat steps 32 and 33.

It can be seen from FIG. 6 that the battery voltage values obtained by the battery voltage judging unit 22 are twice less than 3.952 V (indicated by -1), so the battery capacity adjusting unit 23 performs step 36 to adjust the reference capacity downward according to a certain ratio. One percentage point, that is, 64%, and the cumulative number of times the voltage value is less than the reference voltage is zeroed, and the adjusted reference capacitance 64% is transmitted back to the power management module 41 of the notebook computer 4, so that the power management module 41 The battery capacity can be displayed on the display 42 in time, and then returning to step 31, the battery capacity reading unit 21 reads the current capacity of the battery again, that is, 64% as the reference capacitance, and converts it into a corresponding reference voltage value. When it is 3.945V, then the battery voltage judging unit 22 repeats steps 32-35 to the third time, and finds that only the first voltage is greater than the reference voltage value (indicated by +1), and the second and third voltages are all smaller than the reference voltage value ( Then, the battery capacity adjusting unit 23 resets the cumulative number of times the voltage value is greater than the reference voltage to zero, and proceeds to step 36, and then adjusts the reference capacitance downward by one percentage point, that is, 63%, and the voltage value is Less than The cumulative number of the reference voltage to zero, and the adjusted reference capacitance 63% back to the power management module 41.

Going back to step 31 and repeating steps 32-34 to the third time, it is found that the first acquisition voltage is less than the reference voltage value (indicated by -1), and the second acquisition voltage is greater than the reference voltage value (indicated by +1). The third and fourth voltages are all smaller than the reference voltage value (indicated by +1), and the battery capacity adjusting unit 23 resets the cumulative number of times the voltage value is greater than the reference voltage, and proceeds to step 36, and then adjusts the reference capacitance downward. The percentage point, that is, 62%, and so on, can obtain a voltage value curve 61 as shown in FIG. 6 and a capacitance change line 60 of a fixed slope, and it can be seen from FIG. 6 that even if the battery voltage is discharging In the process, the battery voltage judging unit 22 compares the obtained voltage with the reference voltage, determines whether or not to adjust the capacitance, and controls the battery capacity to be fluctuated without being affected by the voltage value, so that the capacitance can be stabilized. And accurately reflect the voltage value of the battery.

Similarly, the battery capacity calculation device 2 of the present embodiment can also calculate the capacitance of the battery when the notebook computer 4 charges the battery according to the flow of FIG. 4, except that in step 43 of FIG. 4, it is determined whether the battery voltage value is greater than The reference voltage is the number of times the integrated voltage value is greater than the reference voltage in step 44. In step 46, the reference capacitance is adjusted upward according to a certain ratio, for example, the above adjustment is upward by one percentage point, and the remaining processes are the same as when the battery is discharged. Therefore, it will not be repeated here.

Referring to FIG. 7 again, it is a flowchart of a fourth embodiment of the battery capacity calculation method of the present invention, which is different from the above first and second embodiments in that the embodiment can be used in an electronic device such as a notebook computer. Calculate the battery capacity using any stage of the battery, whether charging or discharging. The circuit architecture of the battery capacity calculation device 2 of the present embodiment is as shown in FIG.

Referring to FIG. 5 and FIG. 7, when the notebook computer is powered on, as in steps 31-36 of FIG. 3 above, the battery capacity calculating device 2 performs the steps of FIG. 7 when the battery is powered by the notebook computer. 71-76 to calculate the battery capacity, similarly, the battery capacity reading unit 21 reads a current reference capacity of the battery, and converts the reference capacitance into a corresponding reference voltage, and the battery voltage determination unit 22 reads the battery. a current voltage value, and determining that the voltage value is less than the reference voltage, accumulating the voltage value is less than the reference voltage, and when the cumulative voltage value is less than the reference voltage, the number of times reaches a first preset value, for example, 2 times The battery capacity adjustment unit 23 adjusts the reference capacitance downward by a certain percentage, for example, one percentage point, as described above.

In step 73, when the battery voltage determining unit 22 determines that the voltage value is less than the reference voltage, step 77 is performed to determine whether the voltage value is greater than the reference voltage. If so, and as in 43-45 of FIG. 4, the battery voltage determining unit 22 is heavy. Steps 77-79, the cumulative voltage value is greater than the reference voltage, until the cumulative voltage value is greater than the reference voltage reaches a second preset value, for example, 2 times, indicating that the battery is being charged, then proceed to step 80, battery capacity The adjustment unit 23 adjusts the reference capacitance upward by a certain ratio, for example, one percentage point as described above, and returns the cumulative number of times to zero, and then returns to step 71 to repeat the above steps to continuously calculate the capacitance of the battery.

Therefore, when the battery is in a state of pure charging, the embodiment will perform steps 71-76 to calculate the capacitance of the battery, and when the battery is in a state of pure discharge, the embodiment will perform steps 71-73 and 77-80. To calculate the capacitance of the battery, and when the battery is in the state of simultaneous charging and discharging, the present embodiment alternately performs steps 71-76 and 73-80 to accurately calculate the capacitance of the battery.

The battery capacity calculation device 2 of the present embodiment integrates the battery capacity calculation flow during battery discharge and charging, so that the battery capacity can be accurately calculated in this embodiment regardless of whether the battery is in a state of discharging, charging, or simultaneous discharging and charging. .

It is worth mentioning that the battery capacity calculation device 2 of the third and fourth embodiments described above can also be directly integrated into the power management module 41 of the notebook computer 4.

In summary, the present invention uses the battery voltage determination unit 22 to compare the obtained battery voltage with the reference voltage converted by the current reference capacitance for a plurality of times to determine whether the battery voltage is decreasing or rising, and then determining the downward or By adjusting the capacitance upward, the battery capacity can be controlled not to fluctuate up and down with the voltage value, so that the capacitance can stably and accurately reflect the voltage value of the battery, and the efficacy and purpose of the present invention are indeed achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2. . . Battery capacity calculation device

4. . . Notebook computer

twenty one. . . Battery capacity reading unit

twenty two. . . Battery voltage judgment unit

twenty three. . . Battery capacity adjustment unit

41. . . Power management module

42. . . monitor

31-36. . . step

41-46. . . step

60. . . Voltage value curve

61. . . Capacitance change line

71-80. . . step

1 is a voltage-capacitance correspondence curve of a conventional battery under different charging currents and discharging currents.

Figure 2 is a block diagram showing a detail of a first embodiment of the battery capacity calculating device of the present invention;

3 is a flow chart of a first embodiment of a battery capacity calculation method of the present invention for calculating a capacitance when a battery is discharged;

4 is a flow chart of a second embodiment of a battery capacity calculation method of the present invention for calculating a capacitance when a battery is discharged;

5 is a flow chart of a third embodiment of a method for calculating a battery capacity of the present invention, which is applied to a notebook computer for calculating a capacity of a battery of a notebook computer when discharged;

Figure 6 shows the battery voltage variation and capacitance trend of the third embodiment; and

7 is a flow chart of a fourth embodiment of a battery capacity calculation method of the present invention, which is applied to a notebook computer for calculating the capacitance of a notebook computer when it is used.

31-36. . . step

Claims (10)

A battery capacity calculation method includes: reading a current reference capacity of a battery, the reference capacitance corresponding to a reference voltage; obtaining a current voltage value of the battery; determining whether the voltage value crosses the reference voltage; and determining the voltage When the value crosses the reference voltage, the number of times the voltage value crosses the reference voltage is accumulated; when it is determined that the cumulative value of the voltage value across the reference voltage reaches a preset value, the reference capacitance is adjusted according to a certain ratio. According to the battery capacity calculation method of claim 1, wherein the step of determining whether the voltage value crosses the reference voltage comprises: determining whether the voltage value is less than the reference voltage; and when determining that the voltage value crosses the reference voltage And the step of accumulating the number of times the voltage value crosses the reference voltage comprises: when it is determined that the voltage value is less than the reference voltage, accumulating the number of times the voltage value is less than the reference voltage. According to the battery capacity calculation method of claim 1, wherein the step of determining whether the voltage value crosses the reference voltage comprises: determining whether the voltage value is greater than the reference voltage; and when determining that the voltage value crosses the reference voltage And the step of accumulating the number of times the voltage value crosses the reference voltage comprises: when determining that the voltage value is greater than the reference voltage, accumulating the number of times the voltage value is greater than the reference voltage. According to the battery capacity calculation method of claim 2, wherein when the voltage value is greater than the reference voltage, the cumulative value of the voltage value less than the reference voltage is reset to zero, and when the voltage value is determined to be smaller than The reference voltage is zeroed by the cumulative number of times the voltage value is greater than the reference voltage. According to the battery capacity calculation method of claim 2 or 3, wherein, when the reference capacitance is downwardly adjusted according to a certain ratio, the cumulative value of the voltage value less than the reference voltage is reset to zero; After the ratio adjusts the reference capacitance upward, the cumulative value of the voltage value greater than the reference voltage is reset to zero. A battery capacity calculation device for calculating a battery capacity, the device comprising: a battery capacity reading unit, reading a current reference capacity of the battery, and converting the reference capacitance into a corresponding reference voltage; a battery voltage determining unit reads a current voltage value of the battery, and determines whether the voltage value crosses the reference voltage, and when determining that the voltage value crosses the reference voltage, accumulating the number of times the voltage value crosses the reference voltage; and A battery capacity adjustment unit adjusts the reference capacitance according to a certain ratio when it is determined that the cumulative number of times the voltage value crosses the reference voltage reaches a preset value. The battery capacity calculation device according to claim 6, wherein the battery voltage determination unit determines whether the voltage value is less than the reference voltage, and when determining that the voltage value is less than the reference voltage, accumulating the voltage value is less than the reference The number of voltages. The battery capacity calculation device according to claim 6, wherein the battery voltage determination unit determines whether the voltage value is greater than the reference voltage, and when determining that the voltage value is greater than the reference voltage, accumulating the voltage value is greater than the reference The number of voltages. The battery capacity calculation device according to claim 7 or 8, wherein the battery voltage determination unit determines that the voltage value is greater than the reference voltage, and zeros the cumulative value of the voltage value less than the reference voltage; and the battery When the voltage determination unit determines that the voltage value is less than the reference voltage, the voltage value is greater than the cumulative number of times the reference voltage is zeroed. The battery capacity calculation device according to claim 7 or 8, wherein the battery capacity adjustment unit adjusts the reference capacitance downwardly according to a certain ratio, and resets the cumulative value of the voltage value less than the reference voltage to zero; And after the battery capacity adjusting unit adjusts the reference capacitance upward according to a certain ratio, the accumulated value of the voltage value greater than the reference voltage is reset to zero.