JP6132718B2 - Impedance measuring apparatus and impedance measuring method - Google Patents

Description

  The present invention relates to an impedance measuring device and an impedance measuring method suitable for measuring the internal impedance of a battery.

  As an apparatus related to a measuring apparatus for measuring the internal impedance of this type of battery, the applicant discloses an AC measuring instrument in Japanese Patent Application Laid-Open No. 11-178197. This AC measuring instrument has an AC measurement signal supply source connected to a measurement signal application terminal via a first capacitor for blocking DC, and a first connected between the measurement signal application terminal and the first capacitor. An open / close switch, a measurement circuit connected to a pair of input terminals via a pair of second capacitors for blocking direct current, and a second open / close switch connected between the pair of input terminals and the second capacitor; It has. In this AC measuring instrument, for example, an uninterruptible power supply apparatus is used to measure the voltage across both ends of the measurement target in a state where an AC signal is supplied to the measurement target having a DC electromotive force therein. At this time, since the second capacitor is connected between the measurement object and the measurement circuit, the passage of the direct current component is blocked, so that only the alternating current component included in the voltage across the measurement object is generated. Is input to the measurement circuit, and the internal impedance of the object to be measured is measured based on the measured both-ends voltage. In addition, since the first capacitor is connected between the AC measurement signal supply source and the measurement target, the DC component of the measurement target is prevented from flowing into the AC measurement signal supply source.

  Further, in this AC measuring instrument, for example, when performing impedance measurement of a measurement target having a very large electromotive force such as an in-vehicle battery, an excessive DC voltage higher than a predetermined reference voltage is applied to the input terminal. In some cases, the internal circuits and the like in the measuring device are effectively protected by controlling the first and second open / close switches to the off state and disconnecting the measurement circuit and the AC measurement signal supply source from the measurement target.

Japanese Patent Laid-Open No. 11-178197 (page 2-5, FIG. 1)

  However, the AC measuring instrument disclosed by the applicant has the following problems to be improved. In other words, in the AC measuring instrument disclosed by the applicant, when the DC electromotive force of the measurement target is very large, the measurement circuit and the AC measurement signal supply source are separated from the measurement target, thereby measuring the excessive DC current in the measuring instrument. Although it is possible to effectively protect the internal circuit by preventing the flow into the circuit, there is a problem to be improved that the internal impedance of the measurement target cannot be measured.

  There is also a demand to measure the internal impedance of a battery using an AC measurement signal of an extremely low frequency such as 1 mHz, and in such a case, the capacitance of the first capacitor or the second capacitor for blocking DC is a large impedance. As a result, it causes a measurement error, and there is a problem to be improved that it is difficult to accurately measure the internal impedance of the battery. In this case, it is conceivable to use a capacitor having a large capacity as the first capacitor or the second capacitor. In this case, however, it takes a long time to charge the capacitor, leading to a long measurement time. As a result, new issues to be improved arise.

  This invention is made | formed in view of this subject, and it aims at providing the impedance measuring apparatus and impedance measuring method which can measure the internal impedance of the battery which has a big direct current electromotive force correctly and in a short time.

  In order to achieve the above object, the impedance measuring apparatus according to claim 1, wherein M (M is an even number smaller than N) of N (N is a natural number of 3 or more) of the same type of batteries is forward polarity and reverse. An alternating current supply unit for supplying an alternating current to both ends of a set of batteries connected in series in the same number of polarities; a voltage measuring unit for measuring a voltage at both ends of the set of batteries in a state in which the alternating current is supplied; A processing unit that calculates a total value of internal impedances of the M batteries based at least on a current value flowing through the battery set in a state where an alternating current is supplied and a voltage value of the measured both-ends voltage; The processing unit calculates the total value for each of the N sets in which the combination of the M batteries is different from each other, and each internal impedance of the M batteries in the battery set corresponding to the calculated total value. Calculating said each internal impedance of the N batteries based dance with the relationship to N relational expression respectively.

  The impedance measuring device according to claim 2 is the impedance measuring device according to claim 1, wherein the M of the N batteries are connected in series according to the input control instruction, and the forward polarity and The control instruction is given N times to the scanner unit so that the combination of the M batteries having the same reverse polarity and the M batteries are different from each other, and the AC current supply unit, The voltage measuring unit and the processing unit are controlled to calculate the total value for each of the battery sets connected in series according to the N control instructions, and to control the processing unit to control the N pieces. And a control unit that executes calculation of the internal impedances of the N batteries based on the relational expression.

  Further, according to the impedance measuring method of claim 3, M (M is an even number smaller than N) of N (N is a natural number of 3 or more) of the same type of batteries has the same number of forward and reverse polarities. An alternating current is supplied to both ends of the battery set connected in series in a state, a voltage across the battery set in the state where the alternating current is supplied is measured, and the battery set flows while the alternating current is supplied. An impedance measurement method for calculating a total value of internal impedances of the M batteries based on at least a current value and a voltage value of the measured both-end voltages, wherein N sets of combinations of the M batteries are different from each other. The total value for each is calculated and N relational expressions respectively indicating the relationship between the calculated total value and the internal impedances of the M batteries in the corresponding battery set. Zui by calculating the respective internal impedance of the N batteries.

  In the impedance measuring device according to claim 1 and the impedance measuring method according to claim 3, the battery is very large by connecting M of the N batteries in series with the same number of forward and reverse polarities. Even if it has a DC electromotive force, the voltage across the set of M batteries is extremely small. Therefore, the voltage applied to the measurement circuit (for example, the AC current supply unit, the voltage measurement unit, and the current measurement unit) becomes a small DC voltage. Thus, the internal impedance of the battery can be reliably measured. In addition, since the voltage applied to the measurement circuit is a small DC voltage, it is not necessary to use a DC blocking capacitor that causes measurement errors and lengthens the measurement time. In addition, the internal impedance of the battery can be accurately measured when the internal impedance of the battery is measured using an AC measurement signal having an extremely low frequency.

  According to the impedance measuring apparatus of claim 2, the scanner unit automatically performs N connections such that combinations of M batteries out of N are different from each other in accordance with a control instruction from the processing unit. As a result, a complicated connecting operation for the measurer becomes unnecessary, and as a result, the measurer can measure the internal impedance of the battery extremely reliably and easily.

1 is a configuration diagram showing a configuration of an impedance measuring device 1. It is an equivalent circuit diagram which shows an equivalent circuit when batteries Ba and Bb are connected. It is an equivalent circuit diagram which shows an equivalent circuit when connecting batteries Bb and Bc. It is an equivalent circuit diagram which shows an equivalent circuit when batteries Bc and Ba are connected.

  Hereinafter, embodiments of an impedance measuring apparatus and an impedance measuring method will be described with reference to the accompanying drawings.

  First, the configuration of the impedance measuring apparatus 1 will be described as an example of the impedance measuring apparatus. The impedance measuring apparatus 1 shown in FIG. 1 includes a storage unit 2, a scanner unit 3, an alternating current supply unit 4, a voltage measurement unit 5, a current measurement unit 6, and a processing unit 7. This impedance measuring apparatus 1 is an example in which a plurality of batteries Ba, Bb, Bc (hereinafter also referred to as “battery B” when not distinguished) having the same type of DC electromotive force are measured. As follows, each internal resistance Ra, Rb, Rc (hereinafter also referred to as “internal resistance R” when not distinguished) of each battery B can be measured.

  The storage unit 2 is a container for storing the battery B, and is configured to be capable of storing a plurality (three as an example) of the batteries B. Specifically, the storage unit 2 is also referred to as a “connection terminal 21” when the connection terminals 21a to 21c and 22a to 22c (hereinafter referred to as the connection terminals 21a to 21c) to which wiring can be connected from the outside of the storage unit 2 are not distinguished. When not distinguishing the connection terminals 22a to 22c, they are also referred to as "connection terminals 22") and contacts 23a to 23c connected to the positive electrode of each battery B (hereinafter referred to as "contacts 23" when not distinguished). ), Contacts 24 a to 24 c connected to the negative electrode of each battery B (hereinafter also referred to as “contact 24” when not distinguished), and internal wirings 25 a to 25 c that connect the connection terminal 21 and the contact 23. (Hereinafter, also referred to as “internal wiring 25”) and internal wirings 26a to 26c for connecting the connection terminal 22 and the contact 24 (hereinafter, when not distinguished). It is configured with also referred) and the "internal wiring 26". In the storage unit 2, when the battery B is stored, the contact 23 contacts the positive electrode of each battery B and the contact 24 contacts the negative electrode of each battery B. As a result, the positive of each battery B The electrode is connected to the connection terminal 21 via the internal wiring 25 and the minus electrode is connected to the connection terminal 22 via the internal wiring 26.

  The scanner unit 3 includes a plurality of changeover switches (not shown), and connection terminals 31a to 31c connected to the connection terminals 21a to 21c of the storage unit 2 via external wiring (hereinafter, when not distinguished). , Also referred to as “connection terminal 31”), connection terminals 32a to 32c connected to the connection terminals 22a to 22c of the storage unit 2 via external wiring (hereinafter, also referred to as “connection terminal 32” when not distinguished), In addition, connection terminals 33 a to 33 d connected to the AC current supply unit 4, the current measurement unit 6, and the voltage measurement unit 5 through external wiring are provided. In the scanner unit 3, a plurality of changeover switches are controlled to be turned on / off according to a control signal Sc output from the processing unit 7, and two of the three batteries B have the same number of forward and reverse polarities (in this example, Are connected in series in a state of one by one), and at one end (for example, the positive electrode of the battery Ba in FIG. 2) of both ends of the set of two batteries B connected in series, the connection terminals 21a, 31a, 33a And an inverting input terminal in a differential amplifier circuit 51 (to be described later) of the voltage measuring unit 5 is connected through the connection terminals 21a, 31a, and 33c. A current detection circuit 61 (to be described later) of the current measuring unit 6 is connected to and connected to the other end of the pair (for example, the positive electrode of the battery Bb in the figure) via connection terminals 21b, 31b, and 33b. Terminals 21b, 31b, the non-inverting input terminal is connected in the differential amplifier circuit 51 via 33d. Therefore, in the state where the two batteries B are connected in series as described above, the voltage across the pair of the two batteries B is equal to the DC electromotive force of each battery B when the voltages of the DC electromotive forces of both the batteries B are equal. Since the voltage of the electric power is canceled (cancelled), it becomes almost 0V, and when the voltage of the DC electromotive force of both the batteries B is different, it becomes a differential voltage of both voltages.

  The AC current supply unit 4 is composed of an AC constant current source or an AC current source (an AC current source as an example in this example), and one end of two batteries B connected in series by the scanner unit 3. (A positive electrode of the battery Ba in the example shown in FIG. 2) is connected between the reference potential and an alternating current I as an inspection alternating signal is supplied to a series of batteries B connected in series.

  The voltage measurement unit 5 includes a differential amplifier circuit 51 and an A / D converter 52, and measures both-end voltages at both ends of a pair of batteries B connected in series, which is a voltage measurement target. In this case, in the differential amplifier circuit 51, both input terminals are connected to the scanner unit 3 as described above, and the voltages Va and Vb at both ends of the set of two batteries B are inputted and the inputted voltages are inputted. The voltage difference between Va and Vb is amplified with a predetermined amplification factor, and the voltage across the set of two batteries B is output as the detection voltage Vd. The A / D converter 51 samples the detection voltage Vd output from the differential amplifier circuit 51 at a predetermined sampling rate and converts it into digital data (waveform data) Dv indicating the voltage waveform of the detection voltage Vd. And output to the processing unit 7.

  The current measuring unit 6 includes, for example, a current detection circuit 61 using a shunt resistor and an A / D converter 62. The current detection circuit 61 detects a voltage generated at both ends of the shunt resistor when the alternating current I flows through a set of two batteries B connected in series, and outputs the detection voltage Vi to the A / D converter 62. To do. In addition, the A / D converter 62 samples the detection voltage Vi output from the current detection circuit 61 at the same rate as the sampling rate of the A / D converter 52, thereby alternating current flowing through the set of two batteries B. It is converted into digital data (waveform data) Di indicating a current waveform of current I (the current value is referred to as “current value I”) and output.

  The processing unit 7 is an example of a “processing unit” and a “control unit”, and is configured by a digital circuit including a CPU. The processing unit 7 includes M (in this example, three) batteries B (three in this example). In the example, the control signal Sc is output to the scanner unit 3 so that the combinations for selecting two) are different from each other, and the AC current supply unit 4, the voltage measurement unit 5 and the current measurement unit 6 are controlled, The total value Rt of each internal resistance R for each of the two sets of the batteries B connected in series is the digital data Dv, Di (that is, output from the A / D converter 52 and the A / D converter 62). , Based on the voltage value of the detection voltage Vd and the current value of the alternating current I).

Further, the processing unit 7 outputs the control signal Sc N times (in this example, 3 times) to calculate the total value Rt of each internal resistance R three times, and calculates the calculated total value Rt (Rt1 to Rt1 to be described later) Based on Rt3), N (three in this example) relational expressions necessary for calculating each internal resistance R of the battery B are calculated, and the batteries Ba and Bb are calculated based on the three relational expressions. , Bc internal resistances Ra, Rb, Rc are calculated. Specifically, the total value Rt of the measured internal resistance R of the batteries Ba and Bb is Rt1, the total value Rt of the internal resistance R of the batteries Bb and Bc is Rt2, and the total value of the internal resistance R of the batteries Bc and Ba. Assuming that Rt is Rt3, the following simultaneous equations (relational expressions) of the expression (3) are obtained from the following expressions (1).
Rt1 = Ra + Rb (1) formula Rt2 = Rb + Rc (2) formula Rt3 = Rc + Ra (3) formula Therefore, the processing unit 7 is based on the above three formulas, the batteries Ba, Bb, The internal resistances Ra, Rb, Rc of Bc are calculated based on the following equations (4) to (6). That is, the processing unit 7 calculates the respective internal resistances Ra, Rb, and Rc by substituting the calculated total values Rt1 to Rt3 into the expressions (4) to (6).
Ra = (Rt1-Rt2 + Rt3) / 2 (4) Formula Rb = (Rt1 + Rt2-Rt3) / 2 (5) Formula Rc = (-Rt1 + Rt2 + Rt3) / 2 (6)

  Next, an impedance measurement method for measuring each internal resistance R of the battery B and the operation of the impedance measurement apparatus 1 at that time will be described with reference to the drawings. It is assumed that the connection terminals 31 and 32 of the scanner unit 3 and the connection terminals 21 and 22 of the storage unit 2 are respectively connected in advance via wiring.

  First, the battery B is stored in the storage unit 2. At this time, the contact 23 automatically contacts the plus electrode of each battery B and the contact 24 contacts the minus electrode of each battery B. As a result, the plus electrode of each battery B is connected to the internal wiring 25. The negative electrode is connected to the connection terminal 21 via the internal wiring 26 and is connected to the connection terminal 22 via the internal wiring 26.

  Next, the processing unit 7 outputs the first control signal Sc to the scanner unit 3 to turn on / off the changeover switch in the scanner unit 3 so that two of the batteries B are forward-polarized. In addition, the AC current supply unit 4 is connected to one end of both ends of the set of two batteries B, the current measurement unit 6 is connected to the other end, and both ends are connected to each other. The voltage measuring unit 6 is connected.

  Specifically, an example in which the battery Ba and the battery Bb are connected from the batteries Ba, Bb, and Bc and the total value Rt1 of the internal resistance R is measured will be described with reference to FIG. Hereinafter, the combination of the battery Ba and the battery Bb is also referred to as “battery Ba-Bb”, the combination of the battery Bb and the battery Bc is also referred to as “battery Bb-Bc”, and the combination of the battery Bc and the battery Ba is also referred to as “battery Bc-Ba”.

  First, the processing unit 7 outputs the control signal Sc to the scanner unit 3, and as described above, the battery Ba and the battery Bb are in series, and the forward and reverse polarities are the same number (in this example, one). Connect as follows. That is, the processing unit 7 controls on / off of the changeover switch in the scanner unit 3 to connect the connection terminal 32a and the connection terminal 32b, the connection terminal 31a and the connection terminal 33a, and the connection terminal 31b and the connection terminal. 33b, the connection terminal 31a and the connection terminal 33c, and the connection terminal 31b and the connection terminal 33d, respectively. As a result, the total value Rt1 of the internal resistance R of the batteries Ba-Bb can be measured.

  Next, the processing unit 7 performs control on the AC current supply unit 4, the voltage measurement unit 5, and the current measurement unit 6 to calculate the total value Rt1 of the internal resistance R of the batteries Ba-Bb. Specifically, first, the alternating current supply unit 4 supplies the alternating current I to the batteries Ba-Bb. At this time, the voltage measuring unit 5 detects the voltages generated at both ends of the batteries Ba-Bb as detection voltages Va and Vb, respectively, and outputs them to the differential amplifier circuit 51. Next, the differential amplifier circuit 51 amplifies the difference voltage between the detection voltages Va and Vb with a predetermined amplification factor, and outputs it as a difference voltage Vd between the voltages at both ends of the batteries Ba-Bb. Subsequently, the A / D converter 52 converts the differential voltage Vd output from the differential amplifier circuit 51 into digital data Dv and outputs it. In the current measuring unit 6, the current detection circuit 61 detects a voltage generated at both ends of the shunt resistor when the alternating current I flows through the battery Ba-Bb, and outputs the detection voltage Vi to the A / D converter 62. . The A / D converter 62 converts the detection voltage Vi output from the current detection circuit 61 into digital data Di indicating the current waveform of the alternating current I flowing in the batteries Ba-Bb and outputs the digital data Di.

  Next, the processing unit 7 calculates the total value Rt1 of the internal resistance R of the batteries Ba-Bb based on Di and Dv output from the A / D converters 51 and 62, respectively.

  Next, the processing unit 7 controls the scanner unit 3 so as to obtain a combination (battery Bb-Bc and battery Bc-Ba) that is different from the combination (battery Ba-Bb) selected from the batteries B. The signal Sc is output. At this time, when the battery Bb-Bc is connected and the total value Rt2 of the internal resistance R is measured, the processing unit 7 outputs the control signal Sc, and the battery Bb and the battery Bc are connected as shown in FIG. They are connected in series so that the number of forward and reverse polarities is the same (in this example, one). In other words, the processing unit 7 controls on / off of the changeover switch in the scanner unit 3 to connect the connection terminal 32b and the connection terminal 32c, the connection terminal 31b and the connection terminal 33a, and the connection terminal 31c and the connection terminal. 33b, the connection terminal 31b and the connection terminal 33c, and the connection terminal 31c and the connection terminal 33d, respectively. As a result, the total value Rt2 of the internal resistance R of the batteries Bb-Bc can be measured. Next, the processing unit 7 executes the above-described measurement process to calculate the total value Rt2 of the internal resistance R.

  When the battery Bc-Ba is connected and the total value Rt3 of the internal resistance R is measured, the processing unit 7 outputs the control signal Sc, and the battery Bc and the battery Ba are connected in series as shown in FIG. The forward polarity and the reverse polarity are the same number (1 in this example). That is, the processing unit 7 controls on / off of the changeover switch in the scanner unit 3 to connect the connection terminal 32c and the connection terminal 32a, the connection terminal 31c and the connection terminal 33a, and the connection terminal 31a and the connection terminal. 33b, the connection terminal 31c and the connection terminal 33c, and the connection terminal 31a and the connection terminal 33d, respectively. As a result, the total value Rt3 of the internal resistance R of the battery Bc-Ba can be measured. Next, the processing unit 7 performs the above-described measurement process to calculate the total value Rt3 of the internal resistance R.

  Next, the processing unit 7 calculates each internal resistance Ra, Rb, Rc of each battery B by substituting the calculated total values Rt1 to Rt3 of the internal resistance R into the expressions (4) to (6). .

  Next, an example of measuring the internal impedances Za, Zb, Zc (hereinafter, also referred to as “internal impedance Z” when not distinguished) of the batteries Ba, Bb, Bc will be described.

  In this case, the processing unit 7 calculates the total value Zt of each internal impedance Z for each of the sets of two batteries B connected in series as the digital data Dv, Di (the voltage value of the detection voltage Vd and the AC current I). Current value) at least. Specifically, the processing unit 7 detects the voltage value of the detection voltage Vi indicated by the digital data Dv, the current value of the alternating current I indicated by the digital data Di, the voltage waveform of the detection voltage Vi, and the current of the alternating current I. Based on the phase difference between the waveforms, a total value Zt of each internal impedance Z is calculated.

Further, the processing unit 7 outputs the control signal Sc N times (in this example, 3 times) to calculate the total value Zt of each internal impedance Z three times, and calculates the calculated total value Zt (Zt1 to Zt1 to be described later) Nt (three in this example) relational expressions necessary for calculating each internal impedance Z of the battery B are calculated based on Zt3), and the batteries Ba, Bb are calculated based on the three relational expressions. , Bc internal impedances Za, Zb, Zc are calculated. Specifically, the total value Zt of the measured internal impedances Z of the batteries Ba and Bb is Zt1, the total value Zt of the internal impedances Z of the batteries Bb and Bc is Zt2, and the total value of the internal impedances Z of the batteries Bc and Ba. Zt is Zt3, the total value Rt of the measured internal resistance R of the batteries Ba and Bb is Rt1, the total value Rt of the internal resistance R of the batteries Bb and Bc is Rt2, and the total value of the internal resistance R of the batteries Bc and Ba Rt is Rt3, the total value Xt of the measured internal reactances X of the batteries Ba and Bb is Xt1, the total value Xt of the internal reactances X of the batteries Bb and Bc is Xt2, and the total value of the internal reactances X of the batteries Bc and Ba Assuming that Xt is Xt3, simultaneous equations (relational expressions) of Expression (9) are obtained from Expression (7) below.
Zt1 = Rt1 + jXt1 (7) equation Zt2 = Rt2 + jXt2 (8) equation Zt3 = Rt3 + jXt3 (9) equation

In addition, the following simultaneous equations (relational expressions) are obtained for each real part and each imaginary part of the above expressions (7), (8), and (9).
Rt1 = Ra + Rb (10) Rt2 = Rb + Rc (11) Rt3 = Rc + Ra (12) Xt1 = Xa + Xb (13) Xt2 = Xb + Xc (14) Xt3 = Xc + Xa (15) Formula

The processing unit 7 uses the following formulas (16) for the real parts Ra, Rb, Rc in each internal impedance Z of the batteries Ba, Bb, Bc based on the formulas (10) to (15). To the imaginary part Xa, Xb, Xc in each internal impedance Z is calculated based on the following equations (19) to (21). That is, the processing unit 7 calculates the real number parts Ra, Rb, Rc by substituting the real number parts Rt1, Rt2, Rt3 in the calculated total values Zt1 to Zt3 into the expression (18) from the expression (16). By substituting the imaginary part Xt1, Xt2, Xt3 in the values Zt1 to Zt3 into the expression (21) from the expression (19), the imaginary part Xa, Xb, Xc is calculated.
Ra = (Rt1-Rt2 + Rt3) / 2 (16) Formula Rb = (Rt1 + Rt2-Rt3) / 2 (17) Formula Rc = (-Rt1 + Rt2 + Rt3) / 2 (18) Formula Xa = (Xt1 -Xt2 + Xt3) / 2 (19) Formula Xb = (Xt1 + Xt2-Xt3) / 2 (20) Formula Xc = (-Xt1 + Xt2 + Xt3) / 2 (21)

Finally, the processing unit 7 calculates the internal impedances Za, Zb, Zc of the batteries Ba, Bb, Bc from the real part Ra, Rb, Rc and the imaginary part Xa, Xb, Xc calculated as described above. To do. Since the internal impedance Z is expressed by its absolute value | Z | and the phase difference θ, the processing unit 7 calculates the absolute value | Za | based on the following equations (22) to (27). The phase difference θa, the absolute value | Zb |, the phase difference θb, the absolute value | Zc |, and the phase difference θc are calculated.
| Za | = √ (Ra ² + Xa ² ) (22) Equation θa = arctan (Xa / Ra) (23)
| Zb | = √ (Rb ² + Xb ² ) (24) Equation θb = arctan (Xb / Rb) (25)
| Zc | = √ (Rc ² + Xc ² ) (26) Equation θc = arctan (Xc / Rc) (27)

  As described above, in the impedance measuring apparatus 1 and the impedance measuring method, M (2 in this example) out of N (3 in this example) batteries B have the same number of forward and reverse polarities. When measuring the internal resistance R of each battery B in a state of being connected in series, the total value Rt of the internal resistances R of the M batteries B is calculated, and the calculated total value Rt and the corresponding battery B set Based on N (three in this example) simultaneous equations (relations) indicating the relationship with each internal resistance R of M (two in this example) battery B, N (three in this example). ) To calculate each internal resistance R of the battery B. Further, when measuring the internal impedance Z of each battery B, the total value Zt of each internal impedance Z of the M batteries B is calculated, and M (in this example) in the set of the battery B corresponding to the calculated total value Zt. In this example, N (three in this example) batteries B are based on N (three in this example) simultaneous equations (relationships) indicating the relationship with each internal impedance Z of the battery B. Each internal impedance Z is calculated.

  Therefore, according to the impedance measuring apparatus 1 and the impedance measuring method, even if each battery B has a very large DC electromotive force, the voltage between both ends of a set of M (two in this example) battery B is set. As a result, the voltage applied to the measurement circuit (in this example, the alternating current supply unit 4, the voltage measurement unit 5 and the current measurement unit 6) becomes a sufficiently small voltage. 6, the internal resistance R and the internal impedance Z of each battery B can be reliably measured in the same manner as the measurement using the battery B having a small DC electromotive force voltage as a measurement target.

  In addition, since the voltage applied to the measurement circuit is a small DC voltage, it is not necessary to use a DC blocking capacitor which causes generation of measurement errors and long measurement time. The internal impedance Z can be measured in a short time, and also when the internal resistance R and the internal impedance Z of the battery B are measured using an ultra-low frequency test AC signal (AC current I), the battery B The internal resistance R and the internal impedance Z can be accurately measured.

  Further, according to the impedance measuring apparatus 1, the processing unit 7 outputs the control signal Sc to the scanner unit 3, and M (three in this example) batteries B having the same forward polarity and reverse polarity. By controlling so that the combination of the M batteries B is different from each other, M (two in this example) batteries B are automatically combined. As a result, the measurer can measure the internal resistance R and the internal impedance Z of the battery B extremely reliably and easily.

  In addition, regarding the number of batteries B to be measured, an example in which N = 3 and M = 2 has been described, but not limited to this example, N is an arbitrary natural number of 4 or more, and M is an arbitrary smaller than N Can be defined as an even number. For example, when N = 5, M = 2 or M = 4 can be set. In this case, when measuring the internal resistance R of the battery B, five pieces of the internal resistance R of each battery B can be calculated. The internal resistance R of each battery B can be reliably calculated by appropriately selecting the simultaneous equations (relational expressions), that is, the five combinations that can calculate the internal resistance R of each battery B. In this case, it is preferable to define M as an arbitrary even number and N as (M + 1). By defining in this way, N relational expressions can be easily obtained by simply combining all the batteries B. Further, when the internal impedance Z of the battery B is measured, the internal impedance Z of each battery B can be reliably calculated in the same manner.

  In the impedance measuring apparatus 1 described above, an example in which the alternating current supply unit 4 supplies the alternating current I to the battery B and the current measuring unit 6 measures the current value I of the alternating current I has been described. It is also possible to adopt a configuration in which the unit 4 supplies an alternating constant current having a predetermined current value. According to this configuration, the arrangement of the current measuring unit 6 can be omitted. The battery B includes various batteries such as a primary battery and a secondary battery. Furthermore, although the example which connects minus electrodes in the example which connects two batteries B in series was demonstrated, plus electrodes can also be connected.

DESCRIPTION OF SYMBOLS 1 Impedance measurement apparatus 2 Storage part 3 Scanner part 4 AC current supply part 5 Voltage measurement part 6 Current measurement part 7 Processing part 51 Differential amplifier circuit 52 A / D converter 61 Current detection circuit 62 A / D converter B Battery I Current

Claims (3)

N (N is a natural number of 3 or more) of the same type of batteries, M (M is an even number smaller than N) batteries are connected to both ends of a battery set in series with the same number of forward and reverse polarities. An alternating current supply unit that supplies current; a voltage measurement unit that measures a voltage across the battery set in a state in which the alternating current is supplied; and a current value that flows through the battery set in a state in which the alternating current is supplied. A processing unit that calculates a total value of internal impedances of the M batteries based at least on the measured voltage value of the both-end voltages;
The processing unit calculates the total value for each of the N sets having different combinations of the M batteries, and the internal impedance of the M batteries in the set of batteries corresponding to the calculated total value, An impedance measuring device that calculates the internal impedances of the N batteries based on N relational expressions respectively indicating the relations of   A scanner unit that serially connects the M of the N batteries according to the input control instruction, and the M batteries having the same number of forward and reverse polarities. The control instruction is performed N times for the scanner unit so that the combinations are different from each other, and the AC current supply unit, the voltage measurement unit, and the processing unit are controlled to be connected in series according to the N control instructions. A control unit that calculates the total value for each of the battery sets and controls the processing unit to calculate the internal impedances of the N batteries based on the N relational expressions; The impedance measuring apparatus according to claim 1, further comprising: N (N is a natural number of 3 or more) of the same type of batteries, M (M is an even number smaller than N) batteries are connected to both ends of a battery set in series with the same number of forward and reverse polarities. Supplying current, measuring both-end voltage of the battery set in a state where the alternating current is supplied, a current value flowing through the battery set in the state where the alternating current is supplied, and a voltage value of the measured both-end voltage An impedance measurement method for calculating a total value of internal impedances of the M batteries based on at least
The total value is calculated for each of N sets with different combinations of the M batteries, and the relationship between the calculated total value and the internal impedances of the M batteries in the corresponding battery set is shown. An impedance measuring method for calculating the internal impedances of the N batteries based on N relational expressions.

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