JP2016080363A - Measuring apparatus, measuring method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure internal impedance of a battery to be measured with high accuracy.SOLUTION: A measuring apparatus 1 includes a battery voltage cancel circuit 40 and an impedance measurement part 30. The battery voltage cancel circuit 40 includes a DC power supply battery 41, and an A/D converter 45 for detecting voltage of the DC power supply battery 41. The impedance measurement part 30 controls DC voltage, for subtracting a DC component of a battery B to be measured, so as to be constant on the basis of detection result of the A/D converter 45, even when voltage of the DC power supply battery 41 varies.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measuring apparatus, a measuring method, and a program.

  When measuring the internal impedance of a battery, an AC signal for measurement having a predetermined frequency is supplied to the measured battery, and the voltage value or current value between the terminals of the measured battery in that state is measured.

  In many cases, the impedance measurement is performed in a state where the battery to be measured has an electromotive force (battery voltage). Therefore, there is a technique for preventing the direct current component of the battery to be measured from affecting the measurement (see, for example, Patent Document 1).

JP 2014-10028 A

  In the measuring apparatus of Patent Document 1 described above, a direct-current voltage generator is provided so that the direct current component of the measured battery is canceled by the reverse polarity direct-current component generated from the direct-current voltage generator so as not to affect the measurement. Yes. The DC voltage generator is provided with a DC power supply. Generally, an electronic device that generates a fixed voltage called a voltage reference IC (Integrated Circuit) is used as the DC power supply.

  Such a voltage reference IC generally generates 1 / f noise. Conventionally, the influence of such 1 / f noise on the measurement has been negligible. However, when measuring the internal impedance of a lithium ion battery or the like that has become popular in recent years, the influence on the measurement of 1 / f noise generated by the voltage reference IC cannot be ignored.

  The present invention has been made under such a background, and is capable of measuring the internal impedance of a battery under measurement with high accuracy without being affected by 1 / f noise. As well as providing a program.

  The present invention relates to an AC signal generating means for generating an AC signal for measurement, a voltage detecting means for detecting the voltage of the battery under measurement to which the AC signal for measurement generated by the AC signal generating means is applied, and an AC signal for measurement. Prior to the voltage detecting means detecting the voltage of the measured battery to which the voltage is applied, the battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery, and the measured voltage detected by the voltage detecting means. An impedance measuring means for measuring the impedance of the battery to be measured based on the voltage of the measurement battery, the battery voltage canceling means is a DC power supply battery, a means for detecting the voltage of the DC power supply battery, The impedance measuring means has a direct connection to the measured battery even if the voltage of the DC power supply battery changes based on the detection result of the means for detecting the voltage of the DC power supply battery. And it has a means for controlling a constant DC voltage for subtracting the components.

  Other aspects of the present invention are: AC signal generating means for generating a measuring AC signal; voltage detecting means for detecting the voltage of a battery to be measured to which the measuring AC signal generated by the AC signal generating means is applied; Prior to the voltage detection means detecting the voltage of the measured battery to which the AC signal for measurement is applied, the battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery, and the voltage detection means An impedance measuring method for measuring the impedance of the measured battery based on the detected voltage of the measured battery, and detecting the voltage of the DC power supply battery included in the battery voltage canceling means. And the step of detecting the voltage of the DC power supply battery, even if the voltage of the DC power supply battery changes based on the detection result of the DC power supply battery voltage, And controlling the DC voltage for subtracting the flow components constant, and has a.

  Still another aspect of the present invention is that an information processing device detects an AC signal generating means for generating an AC signal for measurement and a voltage of a battery to be measured to which the AC signal for measurement generated by the AC signal generating means is applied. And a battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery before the voltage detecting means detects the voltage of the measured battery to which the AC signal for measurement is applied. And a DC voltage included in the battery voltage canceling means in a program for realizing a control function of the measuring device having an impedance measuring means for measuring the impedance of the measured battery based on the voltage of the measured battery detected by the voltage detecting means. Even if the voltage of the DC power supply battery changes based on the detection result of the function of detecting the voltage of the power supply battery and the function of detecting the voltage of the DC power supply battery , A function of controlling a constant DC voltage for subtracting the DC component of the measured cell is used for realizing the.

  According to the present invention, the internal impedance of a battery to be measured can be measured with high accuracy without being affected by 1 / f noise.

It is a block block diagram of the measuring apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the measurement control part of FIG. It is a flowchart which shows operation | movement of step S4 in the flowchart of FIG. It is a figure which shows the dispersion | variation in the measurement at the time of using voltage reference IC for a measuring apparatus as a comparative example. It is a figure which shows the dispersion | variation in the measurement in the measuring apparatus which concerns on embodiment of this invention.

  A configuration of the measuring apparatus 1 according to the embodiment of the present invention will be described with reference to FIG. The measuring apparatus 1 includes an AC signal generation circuit 10 that generates a measurement AC signal, a voltage detection circuit 20 that detects the voltage of the battery B to be measured to which the measurement AC signal generated by the AC signal generation circuit 10 is applied, and A battery voltage cancel circuit 40 for generating a DC voltage for subtracting the DC component of the battery B to be measured before the voltage detection circuit 20 detects the voltage of the battery B to be measured to which the AC signal for measurement is applied; And an impedance measuring unit 30 that measures the impedance of the measured battery B based on the voltage of the measured battery B detected by the voltage detection circuit 20 and the current flowing through the measured battery B.

  The AC signal generation circuit 10 supplies the AC signal for measurement to the signal generator 11 that generates the AC signal for measurement, the amplifier 12 that amplifies the AC signal for measurement generated from the signal source 11, and the battery B to be measured. It has terminals Hc and Lc. One end of the terminal Hc is connected to the positive electrode of the battery B to be measured, and the other end of the terminal Hc is connected to the output of the amplifier 12. One end of the terminal Lc is connected to the negative electrode of the battery B to be measured, and the other end of the terminal Lc is grounded. The AC signal for measurement generated from the signal source 11 is controlled so that an AC constant current flows through the battery B to be measured.

  The voltage detection circuit 20 includes a terminal Hp connected to the positive electrode of the measured battery B, a terminal Lp connected to the negative electrode of the measured battery B, operational amplifiers 21 and 22, an amplifier 23, and an A / D converter 24. And resistors R1 and R2.

  For the impedance measuring unit 30, a central processing unit (CPU), a microcomputer, or the like is used. The impedance measuring unit 30 receives the output voltage of the amplifier 23 digitally converted by the A / D converter 24 and calculates the impedance of the battery B to be measured based on the current flowing through the battery B to be measured. Since the current flowing through the battery B to be measured is a constant current, the impedance measurement unit 30 may store the current value in advance, or may be measured by a current detection circuit (not shown). The impedance of the measured battery B calculated by the impedance measuring unit 30 is displayed on a display unit (not shown).

  The battery voltage cancel circuit 40 includes a DC power supply battery 41, a relay 42, operational amplifiers 43 and 44, an A / D converter 45, a D / A converter 46, resistors R3, R4 and R5, and a capacitor. 47. The capacitor 47 removes the noise component output from the operational amplifier 44 by flowing it to the ground.

  The voltage of the DC power supply battery 41 is input to the A / D converter 45 via the relay 42 and the operational amplifier 43, converted into a digital signal, and output to the impedance measuring unit 30. On the other hand, the voltage of the DC power supply battery 41 is input to the D / A converter 46 via the relay 42 and the operational amplifier 43. At this time, the voltage of the DC power supply battery 41 becomes the reference voltage (Vref) for the D / A converter 46. The voltage of the DC power supply battery 41 is input to the negative input terminal of the operational amplifier 44 via the relay 42, the operational amplifier 43, and the resistor R3. The relay 42 is opened when a power switch (not shown) of the measuring apparatus 1 is in an OFF state, thereby preventing the DC power supply battery 41 from being consumed.

  The D / A converter 46 inputs a voltage (hereinafter referred to as a control voltage) for controlling the output voltage of the operational amplifier 44 based on an instruction from the impedance measuring unit 30 to the + input terminal of the operational amplifier 44. That is, the D / A converter 46 sets the voltage of the DC power supply battery 41 as the reference voltage (Vref), and outputs a voltage equal to or lower than the reference voltage (Vref) according to the instruction of the impedance measuring unit 30. The operational amplifier 44 generates an output voltage generated based on a voltage generated by the DC power supply battery 41 applied to the − input terminal and a control voltage output from the D / A converter 46 applied to the + input terminal. The voltage is output to the + input terminal of the operational amplifier 22 of the voltage detection circuit 20 through the resistor R5.

  Here, in the measuring apparatus 1, when the signal source 11 is not generating a signal, adjustment is performed so that the voltage at the point A on the input side of the amplifier 23 is zero volts. That is, when the signal generation source 11 is not generating a signal, the output voltage of the operational amplifier 22 is adjusted to zero volts by adjusting the output voltage of the battery voltage cancellation circuit 40 applied to the positive input terminal of the operational amplifier 22. Adjustments are made. Thereby, the influence which the direct current voltage which the to-be-measured battery B has has on an impedance measurement is removable.

  Specifically, the impedance measuring unit 30 detects the output voltage of the operational amplifier 22 as the voltage at the point A via the amplifier 23 and the A / D converter 24, and cancels the battery voltage so that the detection result becomes zero volts. The output voltage of the circuit 40 is adjusted. At this time, the output voltage of the battery voltage cancel circuit 40 is the output voltage of the operational amplifier 44, and the impedance measuring unit 30 adjusts the output voltage of the operational amplifier 44 by controlling the output voltage of the D / A converter 46. To do.

  For example, when the DC power supply battery 41 is new and the voltage of the DC power supply battery 41 is the highest value, the impedance measurement unit 30 applies a reference voltage (Vref) of (1 / ref) to the D / A converter 46. L), the control voltage output from the D / A converter 46 to the positive input terminal of the operational amplifier 44 is M volts, and at this time, the output of the operational amplifier 44 has a voltage of N volts. Suppose that it occurred. This voltage of N volts is the output voltage of the battery voltage cancel circuit 40, and at this time, the voltage at point A is zero volts. On the other hand, when the DC power supply battery 41 becomes old and the voltage of the DC power supply battery 41 is less than the maximum value, the impedance measurement unit 30 applies the reference voltage (1 / L) to the D / A converter 46 as usual. Since the reference voltage (Vref) is lowered, the control voltage output from the D / A converter 46 to the positive input terminal of the operational amplifier 44 is lower than M volts. Only voltage is output. At such a voltage lower than M volts, the output voltage of the operational amplifier 44 is also lower than N volts, and the voltage at point A may not be adjusted to zero volts.

  Therefore, the impedance measuring unit 30 acquires voltage information of the DC power supply battery 41 from the A / D converter 45, and the D / A converter 46 outputs the voltage information to the + input terminal of the operational amplifier 44 based on the voltage information. In order to increase or decrease the control voltage, the instruction to the D / A converter 46 is changed. That is, when the DC power supply battery 41 is new, if the instruction from the impedance measurement unit 30 to the D / A converter 46 is an instruction to output a voltage (1 / L) of the reference voltage (Vref). When the DC power supply battery 41 becomes old, the instruction from the impedance measurement unit 30 to the D / A converter 46 is to output a voltage of (1 / (L1 (<L)) of the reference voltage (Vref). Thereby, since the control voltage of the D / A converter 46 can maintain M volts, the output voltage of the operational amplifier 44 can also maintain N volts.

  In this way, the impedance measuring unit 30 keeps the output voltage of the operational amplifier 44 constant by changing the instruction to the D / A converter 46 regardless of changes in the voltage of the DC power supply battery 41 over time. The output voltage of the operational amplifier 22 (that is, the voltage at point A) can be adjusted to zero volts.

  Next, a method for measuring the impedance of the battery B to be measured using the measuring apparatus 1 according to the present embodiment will be described with reference to the flowchart of FIG. The START condition in the flowchart of FIG. 2 is a condition that the measuring apparatus 1 is in the ON state and the battery B to be measured is connected to the terminals Hc, Lc, Hp, and Lp. If the START condition is satisfied, the process proceeds to step S1.

  In step S1, the impedance measuring unit 30 determines whether or not the point A shown in FIG. 2 (that is, the output voltage of the operational amplifier 22) is zero volts. If it is determined in step S1 that point A is zero volts, the process proceeds to step S2. On the other hand, if it is determined that the point A is not zero volts, the process proceeds to step S4.

  In step S <b> 2, the impedance measurement unit 30 causes the signal generation source 11 to generate a measurement AC signal. When the measurement AC signal is generated in step S2, the process proceeds to step S3.

  In step S3, the impedance measuring unit 30 measures the impedance of the battery B to be measured, outputs the measurement result to an output unit (not shown), and ends the process (END).

  In step S4, the impedance measuring unit 30 adjusts the output voltage of the battery voltage cancel circuit 40. In step S4, when the output voltage of the battery voltage cancel circuit 40 is adjusted, the process returns to step S1.

  Next, a method for adjusting the output voltage of the battery voltage cancel circuit 40, which is the process of step S4 in the flowchart of FIG. 2, will be described with reference to the flowchart of FIG. The START condition of the flowchart of FIG. 3 is a condition that the process of step S1 of the flowchart of FIG. 2 is No. If No in the process of the flowchart of FIG. 2, the process proceeds to step S <b> 41.

  In step S <b> 41, the impedance measurement unit 30 acquires voltage information of the DC power supply battery 41 from the A / D converter 45. When the voltage information of the DC power supply battery 41 is acquired in step S41, the process proceeds to step S42.

  In step S42, the impedance measuring unit 30 determines whether the voltage of the DC power supply battery 41 is a voltage that can be used for measurement based on the voltage information of the DC power supply battery 41 acquired from the A / D converter 45. Determine whether. If it is determined in step S42 that the voltage of the DC power supply battery 41 is usable for measurement, the process proceeds to step S43. On the other hand, if it is determined that the voltage of the DC power supply battery 41 cannot be used for measurement, the process proceeds to step S44.

  In step S43, the impedance measuring unit 30 changes the instruction value to the D / A converter 46 in accordance with the voltage of the DC power supply battery 41. That is, the impedance measuring unit 30 instructs the D / A converter 46 to output a voltage within a range equal to or lower than the reference voltage (Vref) of the DC power supply battery 41 according to the voltage of the DC power supply battery 41. In step S43, when the instruction value to the D / A converter 46 is changed according to the voltage of the DC power supply battery 41, the process returns to step S1.

  In step S44, the impedance measurement unit 30 displays on the display unit (not shown) that the DC power supply battery 41 is unusable and ends the processing (END). At this time, the process of the flowchart of FIG. 2 is also interrupted in step S4.

  As a result, the output voltage of the operational amplifier 44 can be kept constant even when the voltage of the DC power supply battery 41 changes with time. According to this, even if the voltage of the DC power supply battery 41 changes with time, the voltage applied to the + input terminal of the operational amplifier 22 can be kept constant, so that the voltage of the DC power supply battery 41 changes with time. When the signal source 11 does not generate a measurement AC signal, the output voltage of the operational amplifier 22 (that is, the voltage at point A) can be kept at zero volts.

  Here, as a comparative example, the accuracy when the impedance of the battery B to be measured is measured is compared between when the DC power supply battery 41 is used and when the voltage reference IC is used instead of the DC power supply battery 41. FIG. 4 is a diagram showing the degree of variation in the impedance measurement of the battery B to be measured when the voltage reference IC is used. FIG. 5 is a diagram showing the degree of variation in the impedance measurement of the battery B to be measured when the DC power supply battery 41 is used. 4 and 5 both take the number of measurements on the horizontal axis and the impedance on the vertical axis.

  In FIG. 4, it can be seen that the variation for each number of measurements is about 100 μΩ on average. On the other hand, in FIG. 5, it can be seen that the variation for each number of measurements falls within an average of about 30 μΩ. The variation shown in FIG. 4 is caused by the voltage reference IC having 1 / f noise. In contrast, according to the DC power supply battery 41 having no 1 / f noise, as shown in FIG.

  As described above, by using the DC power supply battery 41 in place of the voltage reference IC, it is possible to realize the impedance measurement of the battery B to be measured with high accuracy with reduced variation. At this time, the output voltage of the battery voltage cancel circuit 40 can be kept constant even if the voltage of the DC power supply battery 41 changes with time.

(Other embodiments)
The impedance measuring unit 30 can be realized by executing a predetermined program in which the information processing apparatus is installed in advance. Such an information processing apparatus has, for example, a memory (not shown), a CPU (Central Processing Unit), an input / output port, and the like. The CPU of the information processing apparatus reads and executes a control program as a predetermined program from a memory or the like. Thereby, the function of the impedance measuring unit 30 is realized in the information processing apparatus. An ASIC (Application Specific Integrated Circuit), a microprocessor (microcomputer), a DSP (Digital Signal Processor), or the like may be used instead of the CPU.

  Further, even if the predetermined program described above is stored in the memory of the information processing apparatus before shipment of the impedance measurement unit 30, it is stored in the memory of the information processing apparatus after shipment of the impedance measurement unit 30. It may be what was done. A part of the program may be stored in a memory of the information processing apparatus after the impedance measurement unit 30 is shipped. The program stored in the memory or the like of the information processing apparatus after the impedance measurement unit 30 is shipped may be, for example, an installed program stored in a computer-readable recording medium such as a CD-ROM. What was downloaded via transmission media, such as, may be installed.

  The predetermined program described above includes not only a program that can be directly executed by the information processing apparatus but also a program that can be executed by being installed on a hard disk or the like. Also included are those that are compressed or encrypted.

  As described above, by realizing the impedance measuring unit 30 with the information processing apparatus and the program, it is possible to flexibly cope with mass production and specification change (or design change).

  Note that the program executed by the information processing apparatus may be a program that is processed in time series in the order described in this specification, or may be necessary in parallel or when a call is made. It may be a program that performs processing at timing.

DESCRIPTION OF SYMBOLS 1 ... Measuring apparatus, 10 ... AC signal generation circuit (AC signal generation means), 20 ... Voltage detection circuit (voltage detection means), 30 ... Impedance measurement part (impedance measurement means, means for controlling DC voltage constant), 40 ... battery voltage cancel circuit (battery voltage canceling means), 41 ... DC power supply battery, 45 ... A / D converter (means for detecting voltage of DC power supply battery), 46 ... D / A converter (DC voltage) Part of the means for constant control), B ... Battery to be measured

Claims (3)

AC signal generating means for generating an AC signal for measurement;
Voltage detecting means for detecting the voltage of the battery under measurement to which the AC signal for measurement generated by the AC signal generating means is applied;
Battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery before the voltage detecting means detects the voltage of the measured battery to which the AC signal for measurement is applied;
Impedance measuring means for measuring the impedance of the measured battery based on the voltage of the measured battery detected by the voltage detecting means;
In a measuring device having
The battery voltage canceling means is
A battery for DC power supply;
Means for detecting the voltage of the battery for DC power supply;
Have
The impedance measuring means includes
Means for controlling the DC voltage for subtracting the DC component of the measured battery to be constant even if the voltage of the DC power supply battery changes based on the detection result of the means for detecting the voltage of the DC power supply battery;
A measuring device. AC signal generating means for generating an AC signal for measurement;
Voltage detecting means for detecting the voltage of the battery under measurement to which the AC signal for measurement generated by the AC signal generating means is applied;
Battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery before the voltage detecting means detects the voltage of the measured battery to which the AC signal for measurement is applied;
Impedance measuring means for measuring the impedance of the measured battery based on the voltage of the measured battery detected by the voltage detecting means;
In an impedance measurement method executed by a measurement device having:
Detecting the voltage of the battery for direct current power supply that the battery voltage canceling means has,
Detecting a DC voltage for subtracting the DC component of the measured battery even if the voltage of the DC power supply battery changes based on the detection result of the step of detecting the voltage of the DC power supply battery; and
Having
A measuring method characterized by the above. In the information processing device,
AC signal generating means for generating an AC signal for measurement;
Voltage detecting means for detecting the voltage of the battery under measurement to which the AC signal for measurement generated by the AC signal generating means is applied;
Battery voltage canceling means for generating a DC voltage for subtracting the DC component of the measured battery before the voltage detecting means detects the voltage of the measured battery to which the AC signal for measurement is applied;
Impedance measuring means for measuring the impedance of the measured battery based on the voltage of the measured battery detected by the voltage detecting means;
In a program for realizing a control function of a measuring apparatus having
A function of detecting the voltage of the battery for direct current power supply possessed by the battery voltage canceling means;
A function of controlling the DC voltage for subtracting the DC component of the measured battery to be constant even if the voltage of the DC power supply battery changes based on the detection result of the function of detecting the voltage of the DC power supply battery;
To realize,
A program characterized by that.

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