JP2012149973A - Internal resistance measurement value calibration circuit of charge element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement value calibration circuit capable of reducing calibration errors caused by potential application to an AC coupling element much more than that in calibration of an internal resistance measurement device by using only a reference resistor.SOLUTION: During the calibration of an internal resistance measurement device 3 using a reference resistor 5, a potential v1 equal to that of a charge element is applied to a capacitor 6 connected between the reference resistor 5 and an AC voltmeter 2 by a DC voltage source 7. Thus, in the state where the potential v1 equal to that applied to the capacitor 6 during the internal resistance measurement of the charge element using the internal resistance measurement device 3 is applied to the capacitor 6 in a measurement value calibration circuit, calibration of the internal resistance measurement device 3 using the reference resistor 5 is executed. During the calibration of the internal resistance measurement device 3 using the reference resistor 5, a capacitance change caused by the potential application to the capacitor 6 satisfies a measurement condition for real internal resistance measurement of the charge element using the internal resistance device 3.

Description

  The present invention relates to a measurement value calibration circuit that calibrates an internal resistance measurement value of a storage element having a potential, which is measured by an internal resistance measurement device.

  Conventionally, in a storage element having a potential such as a battery or an electric double layer capacitor, an internal resistance is measured by an internal resistance measuring instrument, and a determination of a remaining capacity, a deterioration state, and the like is widely performed.

  For the measurement of the internal resistance by the internal resistance measuring instrument, the AC four-terminal meter method is often used because the internal resistance of the storage element itself is small and the storage element has a DC potential. Internal resistance measurement using this AC four-terminal meter method is performed using the internal resistance measuring instrument 3 shown in FIG. When measuring the internal resistance r of the storage element 4, as shown in the figure, the storage element 4 is connected in parallel to the alternating current generator 1 and the alternating current voltmeter 2, and the alternating current generator 1 connects the storage element 4 to the alternating current. The current i is energized. By this energization, an electromotive force v is generated in the storage element 4, and the electromotive force v is measured by the AC voltmeter 2. The internal resistance r of the storage element 4 is obtained by substituting each value of the alternating current i energized by the alternating current generator 1 and the voltage v measured by the alternating current voltmeter 2 into an arithmetic expression r = v ÷ i. Desired.

  As described above, the internal resistance measuring instrument 3 includes the AC current generator 1 that supplies the accumulator element 4 with the AC current i, and the AC voltmeter that measures the voltage fluctuation generated in the accumulator element 4 due to this energization as the electromotive force v. 2 is often included. As a technique for measuring the internal resistance of the storage element in this way, for example, there is a method for measuring the internal impedance of a lead storage battery disclosed in Patent Document 1. In an internal resistance measuring instrument using this internal impedance measuring method, a lead storage battery is used as a storage element, and a measurement current including an alternating current component is passed between an anode and a cathode of the lead storage battery. Then, the anode and cathode of the lead storage battery are used as measurement electrodes, the AC voltage component between both electrodes is detected, and the internal impedance of the lead storage battery is measured.

  2. Description of the Related Art Conventionally, a circuit shown in FIG. 2 is generally widely used as a measurement value calibration circuit for checking whether or not this type of internal resistance measuring instrument correctly measures. In the figure, the same or corresponding parts as in FIG. This measurement value calibration circuit is configured by connecting a reference resistor 5 for calibration to an alternating current generator 1 and an alternating current voltmeter 2 in parallel. The reference resistor 5 is a simulated electric storage element that has a small resistance value, and is calculated based on the value displayed on the voltmeter 2 when a constant alternating current is passed by the alternating current generator 1. The accuracy of the measuring instrument 3 can be confirmed by the equation r = v ÷ i. For example, when the resistance of the reference resistor 5 is 1Ω and a constant current of 1 A is passed by the AC current generator 1, the voltmeter 2 indicates 1V. When a value other than 1V is shown, the measuring instrument 3 is calibrated by saying that the measuring instrument 3 has a deviation.

Japanese Patent No. 2876235

  However, the circuit for measuring the AC voltage v in the actual measuring instrument 3 has a capacitor 6 between the power storage element 4 and the AC voltmeter 2 as shown in FIG. Are often connected as. In the figure, the same or corresponding parts as in FIG.

  Such a measuring instrument 3 in which the AC voltmeter 2 is AC-coupled to the storage element 4 by the capacitor 6 may be connected to the capacitor 6 by the voltage applied from the storage element 4 to the capacitor 6 depending on the type of the capacitor 6 used for AC coupling. The capacitance value changes, and the measured value may deviate from the value of the storage element 4 itself.

  For example, as shown in the graph of FIG. 4, when an aluminum electrolytic capacitor or a tantalum electrolytic capacitor is used as the capacitor 6, the capacitance value does not change even when the applied voltage changes, but a multilayer ceramic capacitor is used. In this case, the capacitance value greatly changes depending on the applied voltage. In the graph, the horizontal axis represents the voltage applied to the capacitor [V], and the vertical axis represents the capacitance change rate [%] of the capacitor expressed as a percentage. In addition, the characteristic line indicated by the solid line in which the measurement points are plotted with black circles is the characteristic of the aluminum electrolytic capacitor, the characteristic line indicated by the dotted line plotted with the x is the characteristic of the tantalum electrolytic capacitor, and is plotted with the black triangles The characteristic line indicated by the alternate long and short dash line indicates the characteristic of the multilayer ceramic capacitor (B characteristic), and the characteristic line indicated by the two-dot chain line plotted with black square marks indicates the characteristic of the multilayer ceramic capacitor (F characteristic).

  For this reason, in the internal resistance measuring circuit shown in FIG. 3, an aluminum electrolytic capacitor or a tantalum electrolytic capacitor may be used as the capacitor 6. However, these capacitors have problems such as large change over time and short life. is there. On the other hand, a multilayer ceramic capacitor is preferable because it has no such problems, has little secular change, and has excellent characteristics such as frequency characteristics, low heat generation, and withstand voltage. However, when a multilayer ceramic (B characteristic), a multilayer ceramic (F characteristic), or the like is used, the impedance of the circuit changes due to a change in the capacitance value of the capacitor 6, and the electric storage element 4 measured by the internal resistance measuring device 3. The internal impedance will change. Therefore, when the internal resistance measuring instrument 3 that measures the internal impedance of the storage element 4 with such a circuit is calibrated by the measurement value calibration circuit shown in FIG. 2 using the reference resistor 5, the internal resistance measuring instrument 3 The internal resistance value of the electricity storage element 4 measured in step (1) is different from the actual internal resistance value, causing a problem that an error occurs.

The present invention has been made to solve such problems,
An alternating current generator for passing an alternating current to a storage element having a potential;
Calibrating the internal resistance measurement value of the storage element measured by the internal resistance measuring instrument configured to include an AC voltmeter that measures an AC voltage generated in the storage element by the alternating current supplied by the alternating current generator; In the measurement value calibration circuit configured by connecting a reference resistor for calibration in parallel to the AC current generator and AC voltmeter,
When measuring the internal resistance of the storage element with the internal resistance meter, an AC coupling element connected between the storage element and the AC voltmeter is connected between the reference resistor and the AC voltmeter, and is equivalent to the potential of the storage element. A potential applying means for applying a potential to the AC coupling element is provided.

  According to this configuration, when the internal resistance measuring instrument using the reference resistor is calibrated, the AC coupling element connected between the reference resistor and the AC voltmeter has a potential equivalent to the potential of the storage element. Given by. Therefore, the reference resistor is used in a state where a potential equivalent to the potential applied to the AC coupling element during measurement of the internal resistance of the storage element using the internal resistance measuring instrument is applied to the AC coupling element in the measurement value calibration circuit. Calibration of the internal resistance measuring instrument was performed. Therefore, when the internal resistance measuring instrument using the reference resistor is calibrated, the change in the characteristic value of the AC coupling element due to the potential applied to the AC coupling element is the same as when measuring the actual internal resistance of the storage element using the internal resistance measuring instrument. The measurement conditions are the same. As a result, compared with the conventional case where the internal resistance measuring instrument is calibrated using only the reference resistor, the calibration error due to the potential application to the AC coupling element can be extremely reduced.

  In addition, the present invention is further characterized by further comprising a potential applying means for applying a potential equivalent to the potential of the power storage element to the alternating current generator.

  According to this configuration, when the internal resistance measuring instrument using the reference resistor is calibrated, a potential equivalent to the potential of the storage element is also given to the alternating current generator by the potential applying means. This is closer to the measurement conditions for measuring the actual internal resistance of the electricity storage device using the resistance measuring instrument. For this reason, the calibration error can be further reduced as compared with the case where a potential equivalent to the potential of the storage element is applied only to the AC coupling element.

  Further, the present invention is characterized in that the potential applying means is constituted by a DC constant voltage circuit that generates a DC constant voltage according to the voltage setting signal.

  According to this configuration, a potential equivalent to the potential of the storage element is generated as a DC constant voltage by the DC constant voltage circuit according to the voltage setting signal. Therefore, by setting the voltage setting signal according to the type of the storage element, a potential equivalent to the potential of the storage element is generated by the DC constant voltage circuit according to the unique potential of each storage element. For this reason, the internal resistance measuring instrument using the reference resistor can be calibrated with the same measured value calibration circuit using the same DC constant voltage circuit for a plurality of types of power storage elements, and the working efficiency of the calibration work is improved.

  According to the present invention, as described above, the calibration error caused by the potential application to the AC coupling element is extremely reduced as compared with the conventional case where the internal resistance measuring instrument is calibrated using only the reference resistor. I can do it.

It is a figure which shows the internal resistance measurement circuit of the electrical storage element using alternating current four terminal meter method. It is a figure which shows the conventional measured value calibration circuit which calibrates the measured value of internal resistance measuring device itself of an electrical storage element. It is a figure which shows the internal resistance measurement circuit of the electrical storage element using the alternating current four-terminal meter method when the electrical storage element and the alternating current voltmeter are AC-coupled. It is a graph which shows the electrostatic capacitance change by the applied voltage of a capacitor | condenser. It is a figure which shows the measured value calibration circuit which calibrates the measured value of the internal resistance measuring device itself of an electrical storage element by the 1st Embodiment of this invention. It is a figure which shows the measured value calibration circuit which calibrates the measured value of internal resistance measuring device itself of the electrical storage element by the 2nd Embodiment of this invention.

    Next, the measured value calibration circuit according to the first embodiment of the present invention for calibrating the measured value of the internal resistance measuring instrument itself of the storage element will be described.

  FIG. 5 is a diagram showing a measured value calibration circuit according to the first embodiment.

  The internal resistance measuring device 3 includes an alternating current generator 1 and an alternating current voltmeter 2, and the storage element is connected in parallel to the alternating current generator 1 and the alternating current voltmeter 2 when measuring the internal resistance r of the unillustrated storage element. Is done. The storage element is an element having a potential such as a battery. An alternating current i is energized to the storage element by the alternating current generator 1, and an electromotive force v generated in the storage element by this energization is measured by the alternating current voltmeter 2. . Then, the internal resistance r of the storage element is obtained by the arithmetic expression r = v ÷ i from each value of the alternating current i supplied to the storage element by the alternating current generator 1 and the voltage v measured by the alternating current voltmeter 2. Is.

  The measured value calibration circuit is configured by connecting a reference resistor 5 in parallel to an alternating current generator 1 and an alternating current voltmeter 2 that constitute the internal resistance measuring device 3 as shown in FIG. A pair of capacitors 6 is connected between the reference resistor 5 and the AC voltmeter 2. This capacitor 6 is connected between the storage element and the AC voltmeter 2 when the internal resistance r of the storage element is measured by the internal resistance measuring instrument 3 as described above, and the AC voltmeter 2 is used as the storage element. It is used as an AC coupling element for AC coupling.

  A DC voltage source 7 is connected in series between the reference resistor 5 and one capacitor 6. This DC voltage source 7 is constituted by a battery or the like, and constitutes a potential applying means that generates a DC potential v1 equivalent to the potential of the electric storage element whose internal resistance r is measured by the internal resistance measuring instrument 3 and applies it to the capacitor 6. is doing.

  A DC voltage source 8 is also connected in series between the reference resistor 5 and the AC current generator 1. This DC voltage source 8 is also constituted by a battery or the like, generates a DC potential v1 equivalent to the potential of the electric storage element whose internal resistance r is measured by the internal resistance measuring device 3, and applies a potential to the AC current generator 1. Means.

  When the storage element whose internal resistance r is measured by the internal resistance measuring instrument 3 is, for example, one cell of a lead storage battery, the DC voltage sources 7 and 8 have a DC potential equivalent to the potential of the storage element. As v1, a 1-cell lead storage battery generating 2.0 [V] was used. The reference resistor 5 is set to a resistance value of 1 [mΩ], for example.

  According to such a measured value calibration circuit according to the present embodiment, when the internal resistance measuring instrument 3 using the reference resistor 5 is calibrated, the capacitor 6 connected between the reference resistor 5 and the AC voltmeter 2 is charged. A potential v1 equivalent to the potential of the element is applied by the DC voltage source 7. Therefore, in the state where the potential v1 equivalent to the potential applied to the capacitor 6 at the time of measuring the internal resistance of the storage element using the internal resistance measuring device 3 is applied to the capacitor 6 in the measured value calibration circuit, the reference resistor 5 is used. The used internal resistance measuring instrument 3 is calibrated. For this reason, when the internal resistance measuring instrument 3 using the reference resistor 5 is calibrated, a change in the characteristic value of the capacitor 6 due to the potential applied to the capacitor 6, that is, a change in the capacitance value is determined using the internal resistance measuring instrument 3. The measurement conditions are the same as when measuring the actual internal resistance of the storage element. As a result, the calibration error due to the potential application to the capacitor 6 can be extremely reduced as compared with the conventional case where the internal resistance measuring device 3 is calibrated using only the reference resistor 5.

  Further, according to the measured value calibration circuit according to the present embodiment, when the internal resistance measuring instrument 3 using the reference resistor 5 is calibrated, the alternating current generator 1 also has a potential v1 equivalent to the potential of the storage element. By being given by the source 8, the measurement condition becomes closer to the measurement condition at the time of measuring the actual internal resistance of the power storage element using the internal resistance measuring device 3. Therefore, the calibration error can be further reduced as compared with the case where the potential v1 equivalent to the potential of the power storage element is applied only to the capacitor 6.

  Next, a measured value calibration circuit according to the second embodiment of the present invention that calibrates the measured value of the internal resistance measuring instrument itself of the storage element will be described.

  FIG. 6 is a diagram showing a measured value calibration circuit according to the second embodiment. In the figure, parts that are the same as or correspond to those in FIG.

  In the measured value calibration circuit according to the present embodiment, only the potential v1 equivalent to the potential of the power storage element whose internal resistance r is measured by the internal resistance measuring device 3 is generated by the DC constant voltage circuits 7a and 8a. This is different from the measurement value calibration circuit according to the first embodiment described above. The configuration other than this is the same as the measurement value calibration circuit according to the first embodiment described above.

  DC constant voltage circuits 7a and 8a generate DC constant voltage v1 according to the voltage setting signal. This DC constant voltage v1 is varied in synchronization with a voltage setting signal input to DC constant voltage circuits 7a and 8a. For example, the storage element is not 2.0 [V] of one lead storage battery, but a lead storage battery having a different potential, such as 6.0 [V] in three cells in series or 12.0 [V] in six cells in series. In this case, the DC constant voltage output from the DC constant voltage circuits 7a and 8a is varied to each value of the potential v1 equivalent to the potential of these storage elements in synchronization with the input voltage setting signal.

  According to such a measured value calibration circuit according to the present embodiment, the potential v1 equivalent to the potential of the storage element is generated as a DC constant voltage by the DC constant voltage circuits 7a and 8a according to the voltage setting signal. Therefore, by setting the voltage setting signal according to the type of the storage element, the potential v1 equivalent to the potential of the storage element is generated by the DC constant voltage circuits 7a and 8a according to the inherent potential of each storage element. Generated. For this reason, the internal resistance measuring instrument 3 using the reference resistor 5 can be calibrated by the same measured value calibration circuit using the same DC constant voltage circuits 7a and 8a for a plurality of types of power storage elements having different intrinsic potentials. Work efficiency is improved.

  In the present embodiment, DC voltage sources 7 and 8 and DC constant voltage circuits 7a and 8a are connected in series between the reference resistor 5 and one capacitor 6 and between the reference resistor 5 and the AC current generator 1, respectively. Although an example of connection is shown, one DC voltage source or a DC constant voltage circuit is connected in series to the reference resistor 5, and the AC current generator 1 and the AC voltmeter 2 are connected to both ends thereof. good.

  In each of the above-described embodiments, the measurement value calibration circuit that calibrates the internal resistance measuring instrument that measures the internal resistance of a battery such as a lead storage battery has been described. However, the measured value calibration circuit according to the present invention may be applied not only to the battery but also to an internal resistance measuring instrument that measures the internal resistance of another electric storage element having a potential, such as an electric double layer capacitor. Even when the measured value calibration circuit according to the present invention is applied to such an internal resistance measuring instrument for measuring the internal resistance of the electric storage element, the same effects as those of the above embodiments can be obtained.

DESCRIPTION OF SYMBOLS 1 ... AC current generator 2 ... AC voltmeter 3 ... Internal resistance measuring device 4 ... Power storage element 5 ... Reference resistor 6 ... Capacitor (AC coupling element)
7, 8 ... DC voltage source 7a, 8a ... DC constant voltage circuit

Claims (3)

An alternating current generator for passing an alternating current to a storage element having a potential;
An internal resistance measurement value of the storage element measured by an internal resistance measuring instrument configured to include an AC voltmeter that measures an AC voltage generated in the storage element by an AC current energized by the AC current generator. In the measured value calibration circuit configured to calibrate, the reference resistor for calibration is connected in parallel to the AC current generator and the AC voltmeter,
An ac coupling element connected between the accumulator element and the ac voltmeter when measuring the internal resistance of the accumulator element by the internal resistance meter is connected between the reference resistor and the ac voltmeter, and the accumulator A measurement value calibration circuit comprising a potential applying means for applying a potential equivalent to a potential of the element to the AC coupling element.   The measured value calibration circuit according to claim 1, further comprising a potential applying unit that applies a potential equivalent to a potential of the power storage element to the alternating current generator.   3. The measured value calibration circuit according to claim 1, wherein the potential applying means is constituted by a DC constant voltage circuit that generates a DC constant voltage according to a voltage setting signal.

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