Contact resistance measuring device and impedance measuring device

Abstract

The main purpose of the present invention is to provide a contact resistance measurement device capable of performing accurate contact inspection. The present invention is provided with: an alternating current source (SS1) that supplies a plurality of determination currents (Ij), which are prescribed at different frequencies (f1-f3), to a current path that includes a contact site to be determined; and a synchronous detection unit (SDU1) that synchronously detects the detection voltage (Vd1) by means of synchronous signals (Sf1-Sf3) having the same frequency (f1-f3) as the frequency of the detection voltage (Vd1), thereby outputting voltages (V1-V3), the voltage values of which vary in accordance with the voltage values of the detection voltages (Vd1) corresponding to the different frequencies (f1-f3). The detection voltage (Vd1) corresponds to the frequency of the judgment current (Ij) when the judgment current (Ij) is supplied from the alternating current source (SS1) and is generated at the judgment object contact part; and a processing unit (CONT) that executes a process for determining whether or not the contact site to be determined is good for each of the different frequencies (f1-f3).

Description

Technical Field

[0001] The present invention relates to a contact resistance measuring device and an impedance measuring device, wherein the contact resistance measuring device supplies an AC current for contact determination to a current path including a contact portion of a determination object, performs processing for determining whether the contact portion of the determination object is good or not based on a DC voltage obtained by synchronously detecting the AC voltage using a synchronous signal having the same frequency as that of the AC voltage generated at the contact portion of the determination object, and the impedance measuring device is equipped with the contact resistance measuring device to measure the impedance of the determination object. Background Art

[0002] For example, as an impedance measuring device having such a contact resistance measuring device, there is known an impedance measuring device disclosed in the following patent document 1. The impedance measuring device comprises: a measurement signal source, which supplies an AC measurement signal to a measurement object (measured sample) via source terminals for supplying signals on the Hi side and the Lo side; and a measuring unit, which measures the voltage generated in the measurement object due to the supply of the measurement signal via sensing terminals for detecting signals on the Hi side and the Lo side. In addition, in the impedance measuring device, the measuring unit comprises: an AC constant current source for disconnection detection, which supplies an AC constant current between the sensing terminal on the Hi side and the sensing terminal on the Lo side in order to detect the contact resistance of each sensing terminal; and two first and second lock-in amplifiers.

[0003] In this impedance measuring device, the frequency f11 of the AC constant current supplied from the measurement signal source and the frequency f12 of the AC constant current supplied from the disconnection detection AC constant current source are set to different frequencies, and the first lock-in amplifier performs synchronous detection at the frequency f11, and the second lock-in amplifier performs synchronous detection at the frequency f12. As a result, the voltage Va generated in the measurement object due to the flow of the measurement AC constant current is output from the first lock-in amplifier, and the voltage Vb generated by the resistance between the Hi side and the Lo side sensing terminals due to the flow of the disconnection detection AC constant current is output from the second lock-in amplifier.

[0004] In this case, if the contact resistance of the source terminal on the Hi side is set to RC1, the contact resistance of the source terminal on the Lo side is set to RC2, the contact resistance of the sense terminal on the Hi side is set to RC3, the contact resistance of the source terminal on the Lo side is set to RC4, and the impedance of the measured object is set to Rx, then the resistance between the sense terminals on the Hi side and the Lo side becomes the combined resistance of the resistance (RC3+Rx+RC4) and the output resistance R01 of the AC constant current source. Therefore, when the output resistance R01>>resistance (RC3+Rx+RC4) and the contact resistance (RC3+RC4)>>impedance Rx, the contact resistance (RC3+RC4) between the sense terminals on the Hi side and the Lo side can be detected based on the above-mentioned voltage Vb, thereby enabling the contact inspection of the sense terminals on the Hi side and the Lo side.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 4695920 (page 7, FIG. 4) Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the impedance measuring device has the following problems that should be improved. Specifically, in the impedance measuring device, a second lock-in amplifier is used to detect the contact resistance between the sensing terminals on the Hi side and the Lo side. At this time, the second lock-in amplifier performs synchronous detection with the frequency f12 of the AC constant current of the AC constant current source for disconnection detection. Therefore, when noise with a frequency that is the same as or close to the frequency f12 of the AC constant current of the AC constant current source for disconnection detection is generated in the surrounding environment, an error will be included in the detection of the resistance (RC3+Rx+RC4), thereby erroneously detecting the contact resistance between the sensing terminals on the Hi side and the Lo side. As a result, in the impedance measuring device, a contact check error occurs, and the state cannot be measured. On the other hand, the state that can be measured can be forced by releasing the setting of the contact check. However, in such a case, the reliability of the impedance measurement performed by the impedance measuring device is reduced. Therefore, in the impedance measuring device, there is a problem that the accuracy of the contact check should be improved, which should be improved.

[0010] The present invention has been made in view of the above problems, and a main object of the present invention is to provide a contact resistance measuring device capable of performing accurate contact inspection and an impedance measuring device capable of improving the reliability of impedance measurement.

[0011] Solutions for solving problems

[0012] In order to achieve the above-mentioned purpose, the contact resistance measuring device of the present invention is a contact resistance measuring device, comprising: a first AC current source, supplying an AC current for contact determination to a current path including a contact portion of a determination object; a synchronous detection unit, performing synchronous detection on the AC voltage using a synchronous signal of a frequency equal to that of the AC voltage, thereby outputting a DC voltage whose voltage value varies according to the voltage value of the AC voltage, wherein the AC voltage corresponds to the frequency of the AC current for contact determination when the AC current for contact determination is supplied from the first AC current source and is generated at the contact portion of the determination object; and a processing unit, performing processing on the contact portion of the determination object based on the DC voltage output from the synchronous detection unit. Processing for determining whether a contact is good or not, in the contact resistance measuring device, the first AC current source is configured to supply a plurality of the contact determination AC currents specified as different frequencies to the current path, and the synchronous detection unit performs synchronous detection on each AC voltage using the synchronization signal having the same frequency as the different frequencies of each AC voltage, thereby outputting the DC voltage whose voltage value varies respectively according to the voltage value of each AC voltage corresponding to the different frequencies, wherein each AC voltage is the AC voltage generated at the contact portion of the determination object when the plurality of contact determination AC currents are supplied to the current path, and the processing unit performs the processing for determining whether a contact is good or not according to each of the different frequencies.

[0013] Therefore, according to the contact resistance measuring device of the present invention, even if noise with a frequency that is the same as or close to one of the different frequencies is generated in the environment surrounding the contact resistance measuring device, it will not affect the contact inspection based on the other frequencies, so the contact resistance measuring device can accurately perform the contact inspection.

[0014] In addition, in the contact resistance measuring device of the present invention, the first AC current source is configured to synthesize a plurality of contact determination AC currents of different frequencies and supply them to the current path, the synchronous detection unit is configured to have a plurality of synchronous detection circuits corresponding to the different frequencies one-to-one, the plurality of synchronous detection circuits respectively use the synchronization signal of the same frequency as the frequency of the AC voltage to synchronously detect the AC voltage, thereby respectively outputting the DC voltage whose voltage value changes according to the voltage value of the AC voltage corresponding to the frequency, wherein the AC voltage is an AC voltage of a frequency corresponding to the different frequencies one-to-one, and the processing unit performs the good or bad determination processing at each of the different frequencies. Therefore, according to the contact resistance measuring device, as a result of outputting the DC voltage simultaneously from each synchronous detection circuit, the good or bad determination processing can be performed simultaneously at each different frequency, so that the contact inspection for the contact part of the determination object can be performed instantly (in a short time).

[0015] In addition, in the contact resistance measuring device of the present invention, the synchronous detection unit sequentially performs synchronous detection on each AC voltage using a synchronous signal having the same frequency as the different frequencies of each AC voltage, thereby sequentially outputting DC voltages whose voltage values ​​change respectively according to the voltage values ​​of each AC voltage corresponding to the different frequencies, and the processing unit performs the goodness determination processing according to each of the different frequencies. Therefore, according to the contact resistance measuring device, compared with the case where the synchronous detection unit is constituted by a plurality of synchronous detection circuits arranged one-to-one corresponding to different frequencies, the synchronous detection unit can be simply constituted and the synchronous detection unit can be constituted inexpensively.

[0016] In addition, in the contact resistance measuring device of the present invention, as the good or bad judgment processing, the processing unit performs the following judgment processing for each of the different frequencies: when the contact resistance of the contact part of the judgment object is less than a predetermined resistance value, the contact resistance of the contact part of the judgment object is set to be good, and when the contact resistance of the contact part of the judgment object is judged to be good more than half of the times of the judgment processing performed, the processing unit finally judges the contact resistance of the contact part of the judgment object to be good. Therefore, according to the contact resistance measuring device, even if noise with a frequency that is the same as or close to one of the different frequencies is generated in the environment around the contact resistance measuring device, it will not affect the contact inspection based on other frequencies, so the contact resistance measuring device can accurately perform contact inspection.

[0017] In addition, in the contact resistance measuring device of the present invention, as the good or bad judgment processing, the processing unit performs the following judgment processing for each of the different frequencies: when the contact resistance of the contact part of the judgment object is less than a predetermined resistance value, the contact resistance of the contact part of the judgment object is set to be good, and when the contact resistance of the contact part of the judgment object is judged to be bad in all the judgment processings performed, the contact resistance of the contact part of the judgment object is finally judged to be bad. Therefore, according to the contact resistance measuring device, as long as noise with the same or close frequency as all the different frequencies is not generated in the environment around the contact resistance measuring device, the contact resistance is finally judged to be good, so the contact resistance measuring device can reduce the occurrence of contact inspection errors in which the contact resistance of the contact part of the judgment object is judged to be bad.

[0018] In addition, the impedance measuring device of the present invention is an impedance measuring device, comprising: a second AC current source, supplying an AC current for measurement to a measurement object, one end and the other end of the measurement object being connected to source terminals on the Hi side and the Lo side, respectively; and a measuring unit, measuring an AC voltage generated between the one end and the other end of the measurement object when the measurement AC current is supplied, via sensing terminals on the Hi side and the Lo side, and measuring the impedance of the measurement object based on the voltage value of the measured AC voltage and the current value of the measurement AC current, wherein the sensing terminals on the Hi side and the Lo side for signal detection are connected to the source terminals on the Hi side and the Lo side, respectively; The terminals are connected to the one end and the other end, respectively, in the impedance measuring device, any of the above-mentioned contact resistance measuring devices is provided, the first alternating current source supplies the contact determination alternating current to at least one of the current paths including the contact parts of the source terminals and the one end and the other end of the measured object and the current paths including the sensing terminals and the one end and the other end of the measured object, and the processing unit performs the goodness determination processing of the contact parts in the at least one current path as the contact parts of the determination object at each of the different frequencies. Therefore, according to the impedance measuring device, even if noise of a frequency that is the same as or close to one of the different frequencies is generated in the environment surrounding the impedance measuring device, it will not affect the contact check based on the other frequencies, so the contact check can be accurately performed, and as a result, the reliability of the impedance measurement can be fully improved.

[0019] Furthermore, in the impedance measuring device of the present invention, the second alternating current source also functions as the first alternating current source, and supplies the measuring alternating current as one of the plurality of contact determination alternating currents of different frequencies to the current path including each source terminal and each contact portion between the one end and the other end of the measuring object. Therefore, according to the impedance measuring device, the second alternating current source also functions as the first alternating current source for supplying the contact determination alternating current, so there is no need to provide two first alternating current sources, and as a result, the impedance measuring device can be simply configured and the impedance measuring device can be configured inexpensively.

[0020] Furthermore, in the impedance measuring device of the present invention, the processing unit outputs the impedance of the measuring object measured by the measuring unit when the contact resistance of the contact portion of the measuring object is finally determined to be good. Therefore, according to the impedance measuring device, the reliability of impedance measurement can be sufficiently improved.

[0021] Effects of the Invention

[0022] According to the contact resistance measuring device of the present invention, even if noise having a frequency identical to or close to one of the different frequencies is generated in the environment surrounding the contact resistance measuring device, it will not affect contact inspection based on other frequencies, so the contact resistance measuring device can accurately perform contact inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a structural diagram showing the structure of the contact resistance measuring device 1 .

[0024] Figure 2 2 is a diagram showing the configuration of the impedance measuring device 100 .

[0025] Figure 3 It is a structural diagram showing the structure of the impedance measurement device 100A. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of a contact resistance measuring device and an impedance measuring device will be described with reference to the drawings.

[0027] First, refer to Figure 1 The contact resistance measuring device 1 will be described.

[0028] The contact resistance measuring device 1 is configured to determine whether the contact resistance at the contact portion of the determination target is good or not, and includes: a pair of terminals (a sensing terminal Hp on the Hi (high) side (also referred to as a sensing terminal for signal detection) and a sensing terminal Lp on the Lo (low) side (a sensing terminal for signal detection)), an AC current source SS1, capacitors C1 and C2, an operational amplifier circuit A1, a filter FIL1, a synchronous detection unit SDU1, comparators COM1 to COM3, a processing unit CONT, and an output unit OUT. In this case, in this example, for example, the contact portion between the sensing terminal Hp and the positive terminal T1 and the contact portion between the sensing terminal Lp and the negative terminal T2 when the sensing terminal Hp and the sensing terminal Lp are connected to one end, i.e., the positive terminal T1, and the other end, i.e., the negative terminal T2 of a battery BAT as a secondary battery, respectively, are used as the determination target contact portion, and it is determined whether the contact resistances RHP and RLP at each of the determination target contact portions are good or not (whether they are smaller than a predetermined resistance value).

[0029] The AC current source SS1 functions as a first AC current source. When a start signal is output from the processing unit CONT, the AC voltage Vj for contact determination is output, and the determination current Ij, which is an AC constant current for contact determination, is started to be supplied to the current path including the contact part of the determination object. When a stop signal is output from the processing unit CONT, the output of the AC voltage Vj for contact determination is stopped, and the supply of the determination current Ij is stopped. In this case, the AC current source SS1 is configured to be able to synthesize a plurality of AC currents (contact determination AC current: as an example, an AC current with a fixed amplitude (known), and three frequencies f1, f2, and f3 that are different from each other) that are specified to have different frequencies as the determination current Ij. However, the determination current Ij may be two AC currents with different frequencies, or may be four or more AC currents with different frequencies. In this example, the determination current Ij supplied from the AC current source SS1 is supplied to a current path that returns to the AC current source SS1 via the coupling capacitor C1, the sensing terminal Hp, the contact portion between the sensing terminal Hp and the positive terminal T1 (the determination target contact portion: the contact resistance RHP), the battery BAT, the contact portion between the negative terminal T2 and the sensing terminal Lp (the determination target contact portion: the contact resistance RLP), and the sensing terminal Lp. In addition, the AC current source SS1 outputs synchronization signals Sf1 to Sf3 of the same frequencies f1, f2, and f3 as the frequencies of the determination current Ij as synchronization signals for synchronization detection to the synchronization detection circuits SD1 to SD3 described later.

[0030] The first amplifier A1 functions as an AC voltage detection unit and is configured to include an operational amplifier OP1, wherein a non-inverting input terminal of the operational amplifier OP1 is connected to the ground G1 via an input resistor R1, and is connected to the sensing terminal Hp via a coupling capacitor C2, and an inverting input terminal is connected to the ground G1 via an input resistor R2, and a feedback resistor R3 is connected between the output terminal and the inverting input terminal, and the operational amplifier OP1 functions as a non-inverting amplifier. According to this configuration, when the determination current Ij is supplied from the AC current source SS1, an AC voltage corresponding to the frequencies f1, f2, and f3 of the determination current Ij and generated at the determination target contact portion (between the sensing terminal Hp and the sensing terminal Lp) is input to the first amplifier A1 via the capacitor C2, and is detected as a detection voltage Vd1 (AC voltage), and the detection voltage Vd1 is amplified at a predetermined amplification factor and output.

[0031] The filter FIL1 is configured as a narrow-band pass filter that mainly passes the AC voltage of the frequency component of the frequency f1, the AC voltage of the frequency component of the frequency f2, and the AC voltage of the frequency component of the frequency f3 contained in the detection voltage Vd1 output from the first amplifier A1. According to this configuration, the detection voltage Vd1 output from the first amplifier A1 is input to the filter FIL1, and the frequency components (noise components) outside the passband contained in the detection voltage Vd1 are removed, and the detection voltage Vd1 is output.

[0032] The synchronous detection unit SDU1 is configured to include: a plurality of (three in this example) synchronous detection circuits SD1 to SD3 provided in one-to-one correspondence with different frequencies f1, f2, and f3; and low-pass filters LPF1 to LPF3 respectively arranged at the subsequent stage of each synchronous detection circuit SD1 to SD3. Here, the synchronous detection circuit SD1 and the low-pass filter LPF1 function as a synchronous detection circuit provided in one-to-one correspondence with the frequency f1, and synchronously detect the detection voltage Vd1 detected by the first amplifier A1 using the synchronous signal Sf1 having the same frequency as the frequency of the detection voltage Vd1, thereby outputting a DC voltage V1 whose voltage value varies according to the voltage value of the detection voltage Vd1. Specifically, as an example, the synchronous detection circuit SD1 is configured to use a multiplier to multiply the detection voltage Vd1 output from the filter FIL1 by the synchronization signal Sf1 output from the AC current source SS1 (in other words, by synchronously detecting the detection voltage Vd1 output from the filter FIL1 using the synchronization signal Sf1), thereby outputting a voltage V1 including a DC voltage whose voltage value changes according to the voltage value (for example, amplitude) of the AC voltage of the determination current Ij based on the frequency f1 among the AC voltages constituting the detection voltage Vd1. In addition, the low-pass filter LPF1 is configured as a low-pass filter, which receives the voltage V1 output from the synchronous detection circuit SD1, removes the AC component and smoothes it, thereby outputting a voltage V1 as a DC voltage whose voltage value changes according to the voltage value of the detection voltage Vd1 of the frequency f1. That is, the synchronous detection circuit (synchronous detection circuit SD1 and low-pass filter LPF1) detects the magnitude of the detection voltage Vd1 corresponding to the frequency f1 of the determination current Ij.

[0033] The synchronous detection circuit SD2 and the low-pass filter LPF2 function as a synchronous detection circuit provided in one-to-one correspondence with the frequency f2, and synchronously detect the detection voltage Vd1 detected by the first amplifier A1 using the synchronous signal Sf2 having the same frequency as the frequency of the detection voltage Vd1, thereby outputting a voltage V2 of a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd1. Specifically, as an example, the synchronous detection circuit SD2 is configured to use a multiplier to multiply the detection voltage Vd1 output from the filter FIL1 by the synchronous signal Sf2 output from the AC current source SS1 (in other words, synchronously detect the detection voltage Vd1 output from the filter FIL1 using the synchronous signal Sf2), thereby outputting a voltage V2 including a DC voltage whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the determination current Ij based on the frequency f2 in the AC voltage constituting the detection voltage Vd1. Furthermore, the low-pass filter LPF2 is configured as a low-pass filter, and receives the voltage V2 output from the synchronous detection circuit SD2 as input, removes the AC component and smoothes it, thereby outputting the voltage V2 as a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd1 of the frequency f2. That is, the synchronous detection circuit (synchronous detection circuit SD2 and low-pass filter LPF2) detects the magnitude of the detection voltage Vd1 corresponding to the frequency f2 of the determination current Ij.

[0034] The synchronous detection circuit SD3 and the low-pass filter LPF3 function as a synchronous detection circuit provided in one-to-one correspondence with the frequency f3, and synchronously detect the detection voltage Vd1 detected by the first amplifier A1 using the synchronous signal Sf3 of the same frequency as the frequency of the detection voltage Vd1, thereby outputting a voltage V3 of a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd1. Specifically, as an example, the synchronous detection circuit SD3 is configured to use a multiplier to multiply the detection voltage Vd1 output from the filter FIL1 by the synchronous signal Sf3 output from the AC current source SS1 (in other words, synchronously detect the detection voltage Vd1 output from the filter FIL1 using the synchronous signal Sf3), thereby outputting a voltage V3 including a DC voltage whose voltage value varies according to the voltage value (for example, amplitude) of the AC voltage of the determination current Ij based on the frequency f3 in the AC voltage constituting the detection voltage Vd1. Furthermore, the low-pass filter LPF3 is configured as a low-pass filter, and receives the voltage V3 output from the synchronous detection circuit SD3 as input, removes the AC component and smoothes it, thereby outputting the voltage V3 as a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd1 of the frequency f3. That is, the synchronous detection circuit (synchronous detection circuit SD3 and low-pass filter LPF3) detects the magnitude of the detection voltage Vd1 corresponding to the frequency f3 of the determination current Ij.

[0035] The comparator COM1, together with other comparators COM2, comparator COM3 and the processing unit CONT, constitutes a "processing unit". In this case, as an example, the comparator COM1 is constituted by an operational amplifier, and a threshold voltage Vth1 of a predetermined voltage is set to the inverting input terminal through the processing unit CONT, and when the voltage V1 output from the low-pass filter LPF1 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth1, a high (high voltage) determination signal S1 is output. In this case, the voltage V1 is a voltage obtained by detecting the voltage generated between the sensing terminal Hp and the sensing terminal Lp based on the determination current Ij of the frequency f1 (that is, the magnitude of the AC voltage corresponding to the frequency f1 of the determination current Ij) in the voltage included in the detection voltage Vd1, and therefore, the voltage value becomes a value proportional to the series composite resistance (RHP+Rx+RLP) of the internal resistance Rx (the resistance value is set to Rx) of the battery BAT, the contact resistance RHP (the resistance value is set to RHP), and the contact resistance RLP (the resistance value is set to RLP) (∝RHP+Rx+RLP). In addition, when the contact resistance (RHP+RLP)>>the internal resistance (Rx), the voltage V1 becomes a voltage whose voltage value represents the magnitude of the contact resistance (RHP+RLP). Therefore, by prescribing the threshold voltage Vth1 as a voltage value corresponding to the maximum resistance value allowed by the contact resistance (RHP+RLP), the comparator COM1 outputs a high determination signal S1 when the contact resistance (RHP+RLP) between the sensing terminal Hp and the sensing terminal Lp is a large resistance value exceeding the maximum resistance value allowed (that is, when the contact is poor). On the contrary, the comparator COM1 outputs a low (low voltage) determination signal S1 when the contact resistance (RHP+RLP) is a small resistance value below the maximum resistance value allowed (that is, when the contact is good).

[0036] As an example, the comparator COM2 is composed of an operational amplifier, and a threshold voltage Vth2 of a predetermined voltage is set to the inverting input terminal through the processing unit CONT. When the voltage V2 output from the low-pass filter LPF2 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth2, a high (high voltage) judgment signal S2 is output. In this case, the voltage V2 is a voltage obtained by detecting the voltage generated between the sensing terminal Hp and the sensing terminal Lp based on the judgment current Ij of the frequency f2 (that is, the magnitude of the AC voltage corresponding to the frequency f2 of the judgment current Ij) in the voltage included in the detection voltage Vd1, so the voltage value becomes a value proportional to the series composite resistance (RHP+Rx+RLP) of the internal resistance Rx of the battery BAT and the contact resistance RHP and the contact resistance RLP (∝RHP+Rx+RLP). In addition, when the contact resistance (RHP+RLP)>>the internal resistance (Rx), the voltage V2 becomes a voltage whose voltage value represents the magnitude of the contact resistance (RHP+RLP). Therefore, by prescribing the threshold voltage Vth2 as a voltage value corresponding to the maximum resistance value allowed by the contact resistance (RHP+RLP), the comparator COM2 outputs a high determination signal S2 when the contact resistance (RHP+RLP) between the sensing terminal Hp and the sensing terminal Lp is a large resistance value exceeding the maximum resistance value allowed (that is, when the contact is poor). On the contrary, the comparator COM2 outputs a low (low voltage) determination signal S2 when the contact resistance (RHP+RLP) is a small resistance value below the maximum resistance value allowed (that is, when the contact is good).

[0037] As an example, the comparator COM3 is composed of an operational amplifier, and a threshold voltage Vth3 of a predetermined voltage is set to the inverting input terminal by the processing unit CONT. When the voltage V3 output from the low-pass filter LPF3 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth3, a high (high voltage) judgment signal S3 is output. In this case, the voltage V3 is a voltage obtained by detecting the voltage generated between the sensing terminal Hp and the sensing terminal Lp based on the judgment current Ij of the frequency f3 (that is, the magnitude of the AC voltage corresponding to the frequency f3 of the judgment current Ij) in the voltage included in the detection voltage Vd1, and therefore, the voltage value becomes a value proportional to the series composite resistance (RHP+Rx+RLP) of the internal resistance Rx of the battery BAT and the contact resistance RHP and the contact resistance RLP (∝RHP+Rx+RLP). In addition, when the contact resistance (RHP+RLP)>>the internal resistance (Rx), the voltage V3 becomes a voltage whose voltage value represents the magnitude of the contact resistance (RHP+RLP). Therefore, by prescribing the threshold voltage Vth3 as a voltage value corresponding to the maximum resistance value allowed by the contact resistance (RHP+RLP), the comparator COM3 outputs a high determination signal S3 when the contact resistance (RHP+RLP) between the sensing terminal Hp and the sensing terminal Lp is a large resistance value exceeding the maximum resistance value allowed (that is, when the contact is poor). On the contrary, the comparator COM3 outputs a low (low voltage) determination signal S3 when the contact resistance (RHP+RLP) is a small resistance value below the maximum resistance value allowed (that is, when the contact is good). It should be noted that the above-mentioned comparison processing of the voltages V1 to V3 and the threshold voltages Vth1 to Vth3 performed by the comparators COM1 to COM3 is equivalent to "a part of the goodness determination processing performed on the determination target contact part at each different frequency based on the DC voltage (in this example, the voltages V1 to V3) output from the synchronous detection unit".

[0038] The processing unit CONT is composed of, for example, a CPU, and functions as a "processing unit" together with the comparators COM1 to COM3. Based on the voltages V1 to V3 of the DC voltages whose voltage values ​​vary according to the voltage values ​​of the detection voltages Vd1 of the AC voltage detected by the first amplifier A1 (in this example, the detection voltages Vd1 of the frequencies f1, f2, and f3), the processing for determining whether the contact portion to be determined (in this example, the contact resistance (RHP+RLP) between the sensing terminal Hp and the sensing terminal Lp) is good or not is performed at each different frequency f1, f2, and f3. Specifically, the processing unit CONT determines whether the contact resistance (RHP+RLP) of the contact portion to be determined is a small resistance value below the maximum resistance value allowed (that is, whether the contact of the contact portion to be determined is good or not) based on the determination signals S1 to S3 outputted from the comparators COM1 to COM3. In addition, the processing unit CONT outputs the display data Sd indicating the processing result of the processing for determining whether the contact portion to be determined is good or not to the output unit OUT. In addition, the processing unit CONT outputs the threshold voltages Vth1 - Vth3 to the corresponding comparators COM1 - COM3 .

[0039] It should be noted that the comparators COM1 to COM3 may be configured as an internal circuit of the processing unit CONT. In the case of adopting this configuration, the arrangement of the comparators COM1 to COM3 after the low-pass filters LPF1 to LPF3 is omitted, and the voltages V1 to V3 output from the low-pass filters LPF1 to LPF3 are directly input to the processing unit CONT. In addition, in this example, the comparators COM1 to COM3 are used to generate the determination signals S1 to S3, but the following configuration may be adopted: the voltages V1 to V3 output from the low-pass filters LPF1 to LPF3 are directly input to the processing unit CONT, and the calculation circuit including the A / D converter inside the processing unit CONT calculates the voltage values ​​of the voltages V1 to V3 to determine whether the contact resistance (RHP+RLP) of the contact portion of the determination object is a small resistance value below the maximum resistance value allowed (that is, whether the contact of the contact portion of the determination object is good). In this case, the processing unit CONT calculates the contact resistance (RHP+RLP) by dividing the voltage values ​​of the voltages V1 to V3 by the known current value of the determination current Ij when the contact resistance (RHP+RLP)>>internal resistance (Rx). In addition, the processing unit CONT can also display the contact resistance (RHP+RLP) by including data for displaying the contact resistance (RHP+RLP) in the display data Sd and outputting it to the output unit OUT when calculating (measuring) the contact resistance (RHP+RLP). It should be noted that the processing unit CONT can also adopt the following configuration: only the calculation of the contact resistance (RHP+RLP) and the output of the display data Sd to the output unit OUT are performed, without determining whether the contact of the determination object contact part is good or not, that is, based on the contact resistance (RHP+RLP) displayed on the output unit OUT, the person who requests the measurement to determine whether the contact of the determination object contact part is good or not. In this case, the calculation of the contact resistance (RHP+RLP) and the output of the display data Sd to the output unit OUT are equivalent to the goodness determination process.

[0040] As an example, the output unit OUT is composed of a display device, and the display data Sd output from the processing unit CONT is input to display whether the contact of the contact part of the determination object is good. In addition, when the display data Sd including data for displaying the contact resistance (RHP+RLP) is input, the output unit OUT displays the resistance value of the contact resistance (RHP+RLP). It should be noted that the output unit OUT can also be composed of various interface circuits instead of the display device. When it is composed of an external interface circuit, it outputs the resistance value of the contact resistance (RHP+RLP) to the external device connected by the transmission path via the external interface circuit, and when it is composed of a medium interface circuit, it stores the resistance value of the contact part of the determination object and the contact resistance (RHP+RLP) in the storage medium connected to the medium interface circuit.

[0041] Next, refer to Figure 1 The operation of the contact resistance measuring device 1 is described. It should be noted that it is assumed that the sensing terminal Hp and the sensing terminal Lp are connected to the positive terminal T1 and the negative terminal T2 of the battery BAT, respectively, via two measurement cables not shown. In addition, the contact resistance between the sensing terminal Hp and the positive terminal T1 of the B battery BAT and the wiring resistance of the measurement cable are referred to as the contact resistance RHP, and the contact resistance between the sensing terminal Lp and the negative terminal T2 of the battery BAT and the wiring resistance of the measurement cable are referred to as the contact resistance RLP. In addition, since the wiring resistance of the measurement cable is a small resistance, it is set to be ignored in the description of this example.

[0042] When the process for determining whether the contact portion of the determination object is good or not is executed, the processing unit CONT outputs a start signal to the AC current source SS1 and outputs threshold voltages Vth1 to Vth3 corresponding to the comparators COM1 to COM3. At this time, the AC current source SS1 outputs the contact determination AC voltage Vj, thereby starting to supply the determination current Ij synthesized by the AC currents of frequencies f1, f2, and f3 to the above-mentioned current path including the determination object contact portion via the capacitor C1, and outputs synchronization signals Sf1 to Sf3 to the synchronous detection circuits SD1 to SD3. As a result, the determination current Ij is supplied between the sensing terminal Hp and the sensing terminal Lp, thereby generating an AC voltage generated by the determination current Ij of frequencies f1, f2, and f3 flowing in the determination object contact portion between the sensing terminal Hp and the positive terminal T1 of the battery BAT and between the negative terminal T2 of the battery BAT and the sensing terminal Lp. In this case, the generated AC voltage is input as the detection voltage Vd1 to the non-inverting input terminal of the operational amplifier OP1 via the capacitor C2. Next, the first amplifier A1 amplifies the input detection voltage Vd1 at a predetermined amplification factor and outputs the amplified voltage to the filter FIL1 .

[0043] Next, the detection voltage Vd1 output from the first amplifier A1 is input to the filter FIL1, and the frequency components (noise components) outside the passband included in the detection voltage Vd1 are removed, and the AC voltage as the frequency components of the frequencies f1, f2, and f3 included in the detection voltage Vd1 is passed as the detection voltage Vd1. Then, the detection voltage Vd1 as the frequency components of the frequencies f1, f2, and f3 that have passed through the filter FIL1 is input to the synchronous detection circuits SD1 to SD3.

[0044] Next, the synchronous detection circuit SD1 performs synchronous detection on the input detection voltage Vd1 using the synchronous signal Sf1 output from the AC current source SS1, and outputs a voltage V1 whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the determination current Ij based on the frequency f1 in the AC voltage constituting the detection voltage Vd1. Then, the voltage V1 output from the synchronous detection circuit SD1 is input to the low-pass filter LPF1, and the AC component is removed and smoothed, thereby outputting the DC voltage V1 to the non-inverting terminal of the comparator COM1. In addition, the synchronous detection circuit SD2 performs synchronous detection on the input detection voltage Vd1 using the synchronous signal Sf2 output from the AC current source SS1, and outputs a voltage V2 whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the determination current Ij based on the frequency f2 in the AC voltage constituting the detection voltage Vd1. Then, the voltage V2 output from the synchronous detection circuit SD2 is input to the low-pass filter LPF2, and the AC component is removed and smoothed, thereby outputting the voltage V2 of the DC voltage to the non-inverting terminal of the comparator COM2. In addition, the synchronous detection circuit SD3 performs synchronous detection on the input detection voltage Vd1 using the synchronization signal Sf3 output from the AC current source SS1, and outputs a voltage V3 whose voltage value changes according to the voltage value (for example, amplitude) of the AC voltage of the determination current Ij based on the frequency f3 in the AC voltage constituting the detection voltage Vd1. Then, the voltage V3 output from the synchronous detection circuit SD3 is input to the low-pass filter LPF3, and the AC component is removed and smoothed, thereby outputting the voltage V3 of the DC voltage to the non-inverting terminal of the comparator COM3.

[0045] Next, as a part of the goodness determination process, the comparator COM1 compares the voltage V1 input to the in-phase terminal with the threshold voltage Vth1 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S1 when the voltage V1 exceeds the voltage value of the threshold voltage Vth1, and outputting a low (low voltage) determination signal S1 to the processing unit CONT when the voltage V1 is less than the voltage value of the threshold voltage Vth1. In this case, when noise with a frequency equal to or close to the frequency f1 is generated in the environment surrounding the contact resistance measuring device 1, the voltage value of the voltage V1 rises, so that the voltage V1 exceeds the voltage value of the threshold voltage Vth1, and as a result, the comparator COM1 outputs a high (high voltage) determination signal S1 indicating that the contact resistance is bad. Similarly, as a part of the goodness determination process, the comparator COM2 compares the voltage V2 input to the in-phase terminal with the threshold voltage Vth2 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S2 when the voltage V2 exceeds the voltage value of the threshold voltage Vth2, and outputting a low (low voltage) determination signal S2 to the processing unit CONT when the voltage V2 is below the voltage value of the threshold voltage Vth2. In this case, when noise with a frequency equal to or close to the frequency f2 is generated in the environment surrounding the contact resistance measuring device 1, the voltage value of the voltage V2 rises, so that the voltage V2 exceeds the voltage value of the threshold voltage Vth2, and as a result, the comparator COM2 outputs a high (high voltage) determination signal S2 indicating that the contact resistance is bad. Similarly, as a part of the good or bad judgment process, the comparator COM3 compares the voltage V3 input to the in-phase terminal with the threshold voltage Vth3 input to the inverting terminal, thereby outputting a high (high voltage) judgment signal S3 when the voltage V3 exceeds the voltage value of the threshold voltage Vth3, and outputting a low (low voltage) judgment signal S3 to the processing unit CONT when the voltage V1 is less than the voltage value of the threshold voltage Vth1. In this case, when noise with a frequency equal to or close to the frequency f3 is generated in the environment around the contact resistance measuring device 1, the voltage value of the voltage V3 rises, so that the voltage V3 exceeds the voltage value of the threshold voltage Vth3, and as a result, the comparator COM3 outputs a high (high voltage) judgment signal S3 indicating that the contact resistance is bad.

[0046] Next, the processing unit CONT performs a goodness determination process at each of the different frequencies f1, f2, and f3 based on the input determination signals S1 to S3. Specifically, the processing unit CONT performs a final determination on whether the contact resistance of the determination target contact portion is good or not as a goodness determination process based on the result of the comparison of the voltages V1, V2, and V3 with the threshold voltages Vth1, Vth2, and Vth3 by the comparators COM1 to COM3 (determination process as a part of the goodness determination process). More specifically, as a good / bad determination process, when the contact resistance of the determination target contact portion is a small resistance value less than a predetermined resistance value (resistance value corresponding to the threshold voltages Vth1 to Vth3) more than half of the multiple (three times in this example) determination processes performed by the comparators COM1 to COM3 at different frequencies f1, f2, and f3, that is, when two or more of the determination signals S1 to S3 are determined to be good and low are output, the processing unit CONT finally determines that the contact resistance of the determination target contact portion is good. On the other hand, when the contact resistance of the determination target contact portion is a small resistance value less than a predetermined resistance value (resistance value corresponding to the threshold voltages Vth1 to Vth3) less than half of the multiple (three times in this example) determination processes performed by the comparators COM1 to COM3, that is, when less than two of the determination signals S1 to S3 are determined to be good and low are output, the processing unit CONT finally determines that the contact resistance of the determination target contact portion is bad. By performing the goodness determination processing in this way, even when noise with a frequency that is the same as or close to a frequency (for example, frequency f1) is generated in the environment surrounding the contact resistance measuring device 1, it will not affect the contact check based on other frequencies (in this example, frequencies f2 and f3), so the contact resistance measuring device 1 (processing unit CONT) can accurately perform the contact check.

[0047] It should be noted that the following processing can also be performed as a goodness determination processing of the processing unit CONT. Specifically, as a goodness determination processing, the processing unit CONT finally determines the contact resistance of the contact part to be determined as bad when the contact resistance of the contact part to be determined is a large resistance value exceeding a predetermined resistance value (threshold voltage Vth1 to Vth3) (that is, when it is determined to be bad) in all (three times in this example) determination processings performed by the comparators COM1 to COM3 at different frequencies f1, f2, and f3, and finally determines the contact resistance of the contact part to be determined as good when the contact resistance of the contact part to be determined is a small resistance value below a predetermined resistance value (threshold voltage Vth1 to Vth3) in at least one of the multiple (three times in this example) determination processings performed by the comparators COM1 to COM3. By executing the goodness determination processing in this way, as long as noise with a frequency that is the same as or close to all of the three frequencies f1, f2, and f3 is not generated in the environment surrounding the contact resistance measuring device 1, the contact resistance will be finally determined to be good. Therefore, the contact resistance measuring device 1 (processing unit CONT) can reduce the occurrence of contact inspection errors in which the contact resistance of the contact portion of the determination object is determined to be poor.

[0048] Then, the processing unit CONT outputs the final determination result of the goodness determination processing to the output unit OUT as display data Sd. Next, the output unit OUT displays whether the contact resistance (RHP+RLP) of the contact part of the determination object is a resistance value smaller than the maximum allowable resistance value based on the display data Sd, that is, displays whether the contact resistance of the contact part of the determination object is good. In this case, when the contact resistance of the contact part of the determination object is displayed as bad, a warning display can also be displayed. In addition, a configuration in which a voice output unit is provided in the output unit OUT to output a warning sound can also be adopted.

[0049] It should be noted that the processing unit CONT may also adopt a configuration in which only the determination results of the determination processing performed multiple times (three times in this example) by the comparators COM1 to COM3 are included in the display data Sd and output to the output unit OUT. When this configuration is adopted, the measurer makes a determination based on the determination results of the determination processing.

[0050] In this way, according to the contact resistance measuring device 1, the AC current source SS1 supplies a plurality of determination currents Ij of different frequencies to the current path, and the synchronous detection circuits SD1~SD3 and the low-pass filters LPF1~LPF3 respectively perform synchronous detection on each detection voltage Vd1 (AC voltages corresponding to the frequencies f1, f2, 3 in the detection voltage Vd1, respectively) using synchronization signals Sf1~Sf3 of the same frequencies as the frequencies f1, f2, 3, respectively, thereby outputting voltages V1~V3 whose voltage values ​​respectively change according to the voltage values ​​of the detection voltage Vd1 corresponding to the frequencies f1, f2, 3, wherein each detection voltage Vd1 corresponds to the different frequencies f1, f2, 3 generated at the contact part of the determination object when the plurality of determination currents Ij are supplied to the above-mentioned current path, and the processing unit CONT performs goodness determination processing according to each frequency f1, f2, 3. Therefore, even if noise with a frequency that is the same as or close to one of the different frequencies (for example, frequency f1) is generated in the environment surrounding the contact resistance measuring device 1, it will not affect the contact check based on other frequencies (in this case, frequencies f2 and f3), so the contact resistance measuring device 1 (processing unit CONT) can accurately perform contact inspection.

[0051] Furthermore, according to the contact resistance measuring device 1, the AC current source SS1 synthesizes a plurality of contact determination AC currents (determination currents Ij of frequencies f1, f2, and f3) of different frequencies and supplies them to the current path, and a plurality of synchronous detection circuits (synchronous detection circuits SD1 to SD3 and low-pass filters LPF1 to LPF3) provided one-to-one in correspondence with the different frequencies f1, f2, and f3 are respectively provided with a synchronous signal (synchronous detection circuit SD1 to SD3 and low-pass filters LPF1 to LPF3) of the same frequency as the frequency of the detection voltage Vd1 (any one of the frequencies f1, f2, and f3). The detection voltage Vd1 of the frequency (any one of the frequencies f1, f2, f3) corresponding to the different frequencies f1, f2, f3 is synchronously detected by the synchronous detection circuit (corresponding to any one of the signals Sf1 to Sf3), thereby outputting a DC voltage (any one of the voltages V1 to V3) whose voltage value changes according to the voltage value of the detection voltage Vd1 corresponding to the frequency (any one of the frequencies f1, f2, f3), and the processing unit CONT performs a good or bad judgment process for each different frequency f1, f2, f3. Therefore, according to the contact resistance measuring device 1, as a result of outputting the voltages V1 to V3 as DC voltages simultaneously from each synchronous detection circuit (SD1 to SD3 and low-pass filters LPF1 to LPF3), the good or bad judgment process can be simultaneously performed for each different frequency f1, f2, f3, so that the contact inspection for the contact part of the judgment object can be performed instantly (in a short time).

[0052] Furthermore, according to the contact resistance measuring device 1, as a process for determining whether the contact resistance (RHP+RLP) of the contact portion to be determined (between the sensing terminal Hp and the sensing terminal Lp) is less than a predetermined resistance value, the processing unit (comparators COM1 to COM3 and processing unit CONT) performs a determination process to set the contact resistance of the contact portion to be determined as good at each of the different frequencies f1, f2, and f3, and when the contact resistance (RHP+RLP) of the contact portion to be determined is determined as good more than half of the times of the determination process performed, the contact resistance (RHP+RLP) of the contact portion to be determined is finally determined as good. Therefore, according to the contact resistance measuring device 1, even if noise of a frequency equal to or close to a frequency (for example, frequency f1) is generated in the environment surrounding the contact resistance measuring device 1, it does not affect the contact inspection based on other frequencies (in this example, frequencies f2 and f3), so the contact resistance measuring device 1 (processing unit CONT) can accurately perform the contact inspection.

[0053] Furthermore, according to the contact resistance measuring device 1, as a process for determining whether the contact resistance (RHP+RLP) of the contact portion to be determined (between the sensing terminal Hp and the sensing terminal Lp) is less than a predetermined resistance value, the processing unit (comparators COM1 to COM3 and processing unit CONT) performs a determination process to set the contact resistance of the contact portion to be determined as good for each of the different frequencies f1, f2, and f3, and finally determines the contact resistance (RHP+RLP) of the contact portion to be determined as bad when the contact resistance is determined as bad in all of the determination processes performed. Therefore, according to the contact resistance measuring device 1, as long as noise having a frequency that is the same as or close to all of the different frequencies f1, f2, and f3 is not generated in the environment surrounding the contact resistance measuring device, the contact resistance is finally determined to be good, and thus the contact resistance measuring device can reduce the occurrence of contact inspection errors in which the contact resistance of the contact portion to be determined is determined to be bad.

[0054] Next, refer to Figure 2 An impedance measuring device that measures the impedance of a measurement object by including the contact resistance measuring device 1 will be described. Components having the same functions as those of the contact resistance measuring device 1 are denoted by the same reference numerals and repeated descriptions are omitted.

[0055] The impedance measuring device 100 includes a source terminal Hc on the Hi side (a source terminal for supplying a measuring AC signal), a source terminal Lc on the Lo side (a source terminal for supplying a measuring AC signal), a measuring AC current source PM, a capacitor C3, a synchronous detection unit SDU2, comparators COM4 and COM5, and a measuring unit MU. The impedance measuring device 100 is configured to measure the internal resistance Rx of the battery BAT as an example of impedance in a state where the source terminal Hc on the Hi side and the sense terminal Hp on the Hi side are connected to the positive terminal T1 (one electrode) of the battery BAT as an example of a measurement object (for example, via a measurement cable not shown), and the source terminal Lc on the Lo side and the sense terminal Lp on the Lo side are connected to the negative terminal T2 (the other electrode) of the battery BAT (for example, via a measurement cable not shown).

[0056] The measuring AC current source PM functions as a first AC current source and a second AC current source, and supplies an output AC current Io to a battery BAT connected between source terminals Hc and Lc on the Hi side and the Lo side. As an example, the measuring AC current source PM includes an AC current source SS2, an operational amplifier OP2, a feedback resistor 4, a grounding resistor 5, and a coupling capacitor C4. In addition, the measuring AC current source PM operates based on a DC voltage (a DC voltage (a DC positive voltage and a DC negative voltage) based on a potential of a ground G2 different from the ground G1) supplied from a power supply system (not shown) for the measuring AC current source PM.

[0057] When the processing unit CONT outputs a measurement start signal, the AC current source SS2 outputs an AC voltage Vo and starts supplying an output AC current Io as an AC constant current for measurement and contact determination to the current path including the battery BAT. When the processing unit CONT outputs a measurement stop signal, the output of the AC voltage Vo is stopped and the supply of the output AC current Io is stopped. In this case, the AC current source SS1 is configured to synthesize a plurality of AC currents with different frequencies (as an example, AC currents with fixed amplitudes (known) and fixed frequencies and two different frequencies f4 and f5) and supply them as output AC current Io. It should be noted that the AC current with a frequency of f4 is used as an AC current for measurement and an AC current for contact determination, and the AC current with a frequency of f5 is used as an AC current for contact determination. In addition, the frequencies f4 and f5 are specified to be different from the above-mentioned frequencies f1, f2, and f3. In addition, the AC current source SS2 outputs synchronization signals Sf4 and Sf5 of frequencies f4 and f5 that are the same as the frequency of the output AC current Io to the later-described synchronous detection circuits SD4 and SD5 as synchronization signals for synchronous detection, and outputs a synchronization signal Sf4 of frequency f4 to the later-described synchronous detection circuit SDR as a synchronization signal for synchronous detection. It should be noted that the AC current source SS2 is not limited to two output AC currents Io of frequencies f4 and f5, and can also be configured to synthesize three or more AC currents that are different from the frequencies f1, f2, and f3 and have different frequencies from each other and supply them as the output AC current Io.

[0058] The operational amplifier OP2 has a feedback resistor R4 connected between the output terminal and the inverting input terminal, and the inverting input terminal is connected to the ground G2 via the grounding resistor R5, and the AC voltage Vo input to the non-inverting input terminal is amplified and output. In addition, the output terminal of the operational amplifier OP2 is connected to the source terminal Hc via the capacitor C4, and the inverting input terminal is connected to the source terminal Lc. According to this structure, the operational amplifier OP2 can output an AC constant current of a known current value obtained by dividing the voltage value of the AC voltage Vo by the resistance value of the grounding resistor 5, and supply it to the battery BAT connected between the source terminals Hc and Lc. In addition, the ground G2, which serves as a reference for the above-mentioned DC voltage (the DC positive voltage and the DC negative voltage for operation) for the measuring AC current source PM, is electrically separated from the ground G1, which serves as a reference for the DC voltage (the DC positive voltage and the DC negative voltage for operation) for the measuring unit MU. Therefore, as shown in FIG. Figure 2As shown, the output AC current Io flows only in the path from the output terminal of the operational amplifier OP2 to the ground G2 via the capacitor C4, the source terminal Hc, the battery BAT, the source terminal Lc, and the grounding resistor 5. It should be noted that the battery BAT in this example is a battery that generates a DC electromotive force, and therefore, in order to prevent the DC electromotive force from being applied to the output terminal of the operational amplifier OP2, the capacitor C4 is provided. Therefore, when the measurement object does not generate a DC electromotive force, it is also possible to adopt a configuration in which the output terminal of the operational amplifier OP2 is directly connected to the source terminal Hc without providing the capacitor C4.

[0059] The synchronous detection unit SDU2 is configured to include: a plurality of (two in this example) synchronous detection circuits SD4 and SD5 provided in one-to-one correspondence with different frequencies f4 and f5; and low-pass filters LPF4 and LPF5 respectively arranged at the subsequent stage of each synchronous detection circuit SD4 and SD5. Here, the synchronous detection circuit SD4 and the low-pass filter LPF4 function as a synchronous detection circuit provided in one-to-one correspondence with the frequency f4, and synchronously detect the AC voltage Vd3 generated at the source terminal Hc when the output AC current Io is supplied from the measurement AC current source PM using the synchronous signal Sf4 having the same frequency as the frequency of the detection voltage Vd3, thereby outputting a DC voltage V4 whose voltage value changes according to the voltage value of the detection voltage Vd3. Specifically, as an example, the synchronous detection circuit SD4 is configured to use a multiplier to multiply the detection voltage Vd3 by the synchronization signal Sf4 output from the AC current source SS2 (in other words, by performing synchronous detection on the detection voltage Vd3 using the synchronization signal Sf4), thereby outputting a voltage V4, wherein the voltage V4 includes a DC voltage whose voltage value varies according to the voltage value (for example, amplitude) of the AC voltage of the output AC current Io based on the frequency f4 in the AC voltage constituting the detection voltage Vd3. In addition, the low-pass filter LPF4 is configured as a low-pass filter, which receives the voltage V4 output from the synchronous detection circuit SD4, removes the AC component and smoothes it, thereby outputting a voltage V4 as a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd3 of the frequency f4. That is, the synchronous detection circuit (synchronous detection circuit SD4 and low-pass filter LPF4) detects the magnitude of the detection voltage Vd3 corresponding to the frequency f4 of the output AC current Io.

[0060] The synchronous detection circuit SD5 and the low-pass filter LPF5 function as a synchronous detection circuit provided in one-to-one correspondence with the frequency f5, and synchronously detect the AC voltage Vd3 generated at the source terminal Hc when the output AC current Io is supplied from the AC current source PM for measurement by using the synchronous signal Sf5 having the same frequency as the frequency of the detection voltage Vd3, thereby outputting a voltage V5 of a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd3. Specifically, as an example, the synchronous detection circuit SD5 is configured to use a multiplier to multiply the detection voltage Vd3 by the synchronous signal Sf5 output from the AC current source SS2 (in other words, by synchronously detecting the detection voltage Vd3 using the synchronous signal Sf5), thereby outputting a voltage V5 including a DC voltage whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the output AC current Io based on the frequency f5 in the AC voltage constituting the detection voltage Vd3. Furthermore, the low-pass filter LPF5 is configured as a low-pass filter, and inputs the voltage V5 output from the synchronous detection circuit SD5, removes the AC component and smoothes it, thereby outputting the voltage V5 as a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd3 of the frequency f5. That is, the synchronous detection circuit (synchronous detection circuit SD5 and low-pass filter LPF5) detects the magnitude of the detection voltage Vd3 corresponding to the frequency f5 of the output AC current Io.

[0061] The comparator COM4, ​​the comparators COM1 to COM3, COM5 and the processing unit CONT together constitute a "processing unit". In this case, as an example, the comparator COM4 is composed of an operational amplifier, and a threshold voltage Vth4 of a predetermined voltage is set to the inverting input terminal through the processing unit CONT, and when the voltage V4 output from the low-pass filter LPF4 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth4, a high (high voltage) determination signal S4 is output. In this case, the voltage V4 is a voltage obtained by detecting the voltage generated between the source terminal Hc and the ground G2 based on the output AC current Io of the frequency f4 (that is, the magnitude of the AC voltage corresponding to the frequency f4 of the output AC current Io) in the voltage included in the detection voltage Vd3, and therefore, the voltage value becomes a value proportional to the series composite resistance (RHC+Rx+RLC) of the internal resistance Rx (the resistance value is set to Rx) of the battery BAT, the contact resistance RHC (the resistance value is set to RHC), and the contact resistance RLC (the resistance value is set to RLC) (∝RHC+Rx+RLC). In addition, when the contact resistance (RHC+RLC)>>internal resistance (Rx), the voltage V4 becomes a voltage whose voltage value represents the magnitude of the contact resistance (RHC+RLC). Therefore, by prescribing the threshold voltage Vth4 as a voltage value corresponding to the maximum resistance value allowed by the contact resistance (RHC+RLC), the comparator COM4 outputs a high determination signal S4 when the contact resistance (RHP+RLP) between the source terminal Hc and the ground G2 is a large resistance value exceeding the maximum resistance value allowed (that is, when the contact is poor). On the contrary, the comparator COM4 outputs a low (low voltage) determination signal S4 when the contact resistance (RHP+RLP) is a small resistance value below the maximum resistance value allowed (that is, when the contact is good).

[0062] As an example, the comparator COM5 is composed of an operational amplifier, and a threshold voltage Vth5 of a predetermined voltage is set to the inverting input terminal through the processing unit CONT. When the voltage V5 output from the low-pass filter LPF5 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth5, a high (high voltage) judgment signal S5 is output. In this case, the voltage V5 is a voltage obtained by detecting the voltage generated between the source terminal Hc and the ground G2 based on the output AC current Io of the frequency f5 (that is, the magnitude of the AC voltage corresponding to the frequency f5 of the output AC current Io) in the voltage included in the detection voltage Vd3, so the voltage value becomes a value proportional to the internal resistance Rx of the battery BAT and the series composite resistance (RHC+Rx+RLC) of the contact resistance RHC and the contact resistance RLC (∝RHC+Rx+RLC). In addition, when the contact resistance (RHC+RLC)>>the internal resistance (Rx), the voltage V5 becomes a voltage whose voltage value represents the magnitude of the contact resistance (RHC+RLC). Therefore, by predetermining the threshold voltage Vth5 as a voltage value corresponding to the maximum resistance value allowed by the contact resistance (RHC+RLC), the comparator COM5 outputs a high determination signal S5 when the contact resistance (RHP+RLP) between the source terminal Hc and the ground G2 is a large resistance value exceeding the maximum resistance value allowed (that is, when the contact is poor). On the contrary, the comparator COM5 outputs a low (low voltage) determination signal S5 when the contact resistance (RHP+RLP) is a small resistance value below the maximum resistance value allowed (that is, when the contact is good). It should be noted that, usually, the resistance value R4 of the feedback resistor R4>>contact resistance (RHP+RLP), so the existence of the resistance value R4 is ignored. In addition, when the contact resistance (RHP+RLP) is a large resistance value exceeding the maximum resistance value allowed, the contact resistance (RHC+RLC)>>the resistance value R5 of the grounding resistor R5, so the existence of the resistance value R5 is ignored.

[0063] In addition to the configuration of the contact resistance measuring device 1 described above, the measuring unit MU is further configured to include a synchronous detection circuit SDR, a low-pass filter LPFR, and an A / D converter AD1. In addition to the above functions in the contact resistance measuring device 1, the processing unit CONT outputs a threshold voltage Vth4 to the synchronous detection circuit SD4, outputs a threshold voltage Vth5 to the synchronous detection circuit SD5, inputs determination signals S4 and S5 from the comparators COM4 and COM5, and inputs a voltage signal SR described later from the A / D converter AD1. In addition, the processing unit CONT performs a goodness determination process for the determination target contact portion (in this example, between the source terminal Hc and the source terminal Lc and between the sense terminal Hp and the sense terminal Lp), based on the determination signals S1 to S5, and also functions as a measuring unit that measures (calculates) the internal resistance Rx of the battery BAT, and measures the internal resistance Rx (an example of impedance) of the battery BAT as the measurement target based on the voltage signal SR.

[0064] As an example, the synchronous detection circuit SDR is configured to use a multiplier to multiply the detection voltage Vd2 of the AC voltage outputted via the filter FIL1 detected by the first amplifier A1 by the synchronization signal Sf4 outputted from the AC current source SS2 (in other words, by synchronously detecting the detection voltage Vd2 outputted from the filter FIL1 using the synchronization signal Sf4), thereby outputting a voltage VR, wherein the voltage VR includes a DC voltage whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the output AC current Io based on the frequency f4 in the AC voltage constituting the detection voltage Vd2. In addition, the low-pass filter LPFR is configured as a low-pass filter, which receives the voltage VR outputted from the synchronous detection circuit SDR, removes the AC component and smoothes it, thereby outputting a voltage VR as a DC voltage whose voltage value varies according to the voltage value of the detection voltage Vd2 of the frequency f4. That is, the synchronous detection circuit (synchronous detection circuit SDR and low-pass filter LPFR) detects the magnitude of the detection voltage Vd2 corresponding to the frequency f4 of the output AC current Io.

[0065] The A / D converter AD1 performs A / D conversion on the voltage VR output from the low-pass filter LPFR, and outputs a voltage signal SR indicating a voltage value proportional to the magnitude of the internal resistance Rx of the battery BAT to the processing unit CONT.

[0066] In addition to the above functions, the output unit OUT also uses the source terminal Hc and the source terminal Lc as the contact part of the determination object to display whether the contact is good. In addition, when the display data Sd including data for displaying the contact resistance (RHC+RLC) and the internal resistance Rx of the battery BAT is input, the contact resistance (RHP+RLP) and the resistance value of the internal resistance Rx are displayed. In addition, when the output unit OUT is composed of an external interface circuit, it outputs the determination object contact part whether the contact is good, the contact resistance (RHC+RLC), (RHP+RLP) and the resistance value of the internal resistance Rx to the external device connected by the transmission path via the external interface circuit, and when it is composed of a medium interface circuit, the determination object contact part whether the contact is good, the contact resistance (RHC+RLC), (RHP+RLP) and the resistance value of the internal resistance Rx are stored in the storage medium connected to the medium interface circuit.

[0067] Next, the operation of the impedance measuring device 100 is described. It should be noted that for the same operation as the above-mentioned contact resistance measuring device 1, repeated descriptions are omitted. In addition, it is assumed that the source terminal Hc and the source terminal Lc are respectively connected to the positive terminal T1 and the negative terminal T2 of the battery BAT via two measurement cables not shown in the figure, and the sensing terminal Hp and the sensing terminal Lp are respectively connected to the positive terminal T1 and the negative terminal T2 of the battery BAT via two measurement cables not shown in the figure. In addition, the contact resistance between the source terminal Hc and the positive terminal T1 of the battery BAT and the wiring resistance of the measurement cable are set to contact resistance RHC, and the contact resistance between the source terminal Lc and the negative terminal T2 of the battery BAT and the wiring resistance of the measurement cable are set to contact resistance RLC. In addition, since the wiring resistance of the measurement cable is a small resistance, it is set to be ignored in the description of this example.

[0068] When measuring impedance, the processing unit CONT outputs a start signal to the measuring AC current source PM and the AC current source SS1, and the processing unit CONT outputs threshold voltages Vth1 to Vth5 corresponding to the comparators COM1 to COM5. At this time, the measuring AC current source PM outputs the output AC current Io, and starts to supply the output AC current Io synthesized by the AC currents of frequencies f4 and f5 to the current path including the contact part of the determination object between the source terminal Hc and the positive terminal T1 of the battery BAT and between the source terminal Lc and the negative terminal T2 of the battery BAT. At this time, the output AC current Io flows through the current path composed of the output terminal of the operational amplifier OP2, the capacitor C4, the source terminal Hc, the battery BAT, the source terminal Lc, the grounding resistor R5 and the ground G2. In addition, the AC current source SS2 outputs the synchronization signal Sf4 to the synchronous detection circuits SD4 and SDR, and outputs the synchronization signal Sf5 to the synchronous detection circuit SD5. As a result, the output AC current Io is supplied between the source terminal Hc and the source terminal Lc, and an AC voltage is generated at the contact portion of the determination target between the source terminal Hc and the positive terminal T1 of the battery BAT and between the negative terminal T2 of the battery BAT and the source terminal Lc due to the flow of the output AC current Io of the frequency f4 and f5. In this case, the generated AC voltage is input to the synchronous detection circuits SD4 and SD5 via the capacitor C3 as the detection voltage Vd3.

[0069] Next, the synchronous detection circuit SD4 performs synchronous detection on the input detection voltage Vd3 using the synchronous signal Sf4 output from the AC current source SS2, and outputs a voltage V4 whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the output AC current Io based on the frequency V4 in the AC voltage constituting the detection voltage Vd3. Then, the voltage V4 output from the synchronous detection circuit SD4 is input to the low-pass filter LPF4, and the AC component is removed and smoothed, thereby outputting the DC voltage V4 to the non-inverting terminal of the comparator COM4. In addition, the synchronous detection circuit SD5 performs synchronous detection on the input detection voltage Vd3 using the synchronous signal Sf5 output from the AC current source SS2, and outputs a voltage V5 whose voltage value varies according to the voltage value (e.g., amplitude) of the AC voltage of the output AC current Io based on the frequency f5 in the AC voltage constituting the detection voltage Vd3. Then, the voltage V5 output from the synchronous detection circuit SD4 is input to the low-pass filter LPF5, and the AC component is removed and smoothed, thereby outputting the voltage V2 of the DC voltage to the non-inverting terminal of the comparator COM5.

[0070] Next, as a part of the goodness determination process, the comparator COM4 compares the voltage V4 input to the in-phase terminal with the threshold voltage Vth4 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S4 when the voltage V4 exceeds the voltage value of the threshold voltage Vth4, and outputting a low (low voltage) determination signal S4 to the processing unit CONT when the voltage V4 is below the voltage value of the threshold voltage Vth4. Similarly, as a part of the goodness determination process, the comparator COM5 compares the voltage V5 input to the in-phase terminal with the threshold voltage Vth5 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S5 when the voltage V5 exceeds the voltage value of the threshold voltage Vth5, and outputting a low (low voltage) determination signal S5 to the processing unit CONT when the voltage V5 is below the voltage value of the threshold voltage Vth5.

[0071] Next, the processing unit CONT performs the above-mentioned good or bad determination processing based on the input determination signals S1 to S3. Specifically, the processing unit CONT performs a final determination as to whether the contact resistance of the determination target contact parts between the sense terminal Hp and the positive terminal T1 of the battery BAT and between the source terminal Hc and the negative terminal T2 of the battery BAT is good or bad based on the result of the comparison of the voltages V1 to V3 and the threshold voltages Vth1 to Vth3 by the comparators COM1 to COM3 (determination processing as a part of the good or bad determination processing).

[0072] Furthermore, the processing unit CONT performs a goodness determination process at each of the different frequencies f4 and f5 based on the input determination signals S4 and S5. Specifically, based on the result of the comparison between the voltages V4 and V5 and the threshold voltages Vth4 and Vth5 by the comparators COM4 and COM5 (determination process as a part of the goodness determination process), as the goodness determination process, a final determination is made as to whether the contact resistance of the determination target contact parts between the source terminal Hc and the positive terminal T1 of the battery BAT and between the source terminal Lc and the negative terminal T2 of the battery BAT is good. More specifically, as a process for determining whether the contact resistance is good or not, the processing unit CONT determines that the contact resistance of the contact portion of the object is a small resistance value below a predetermined resistance value (the resistance value corresponding to the threshold voltages Vth4 and Vth5) more than half the number of times (also twice the total number in this example) of the determination processes performed by the comparators COM4 and COM5 at each different frequency f4 and f5 (that is, when determined to be good), the contact resistance of the contact portion of the object is finally determined to be good; and determines that the contact resistance of the contact portion of the object is a small resistance value below a predetermined resistance value (the resistance value corresponding to the threshold voltages Vth4 and Vth5) less than half the number of times (also once in this example) of the determination processes performed by the comparators COM4 and COM5 at each different frequency f4 and f5. By performing the goodness determination processing in this way, even when noise with a frequency that is the same as or close to multiple frequencies (for example, frequency f5) is generated in the environment surrounding the contact resistance measuring device 1, it will not affect the contact check based on other frequencies (f4 in this example), so the impedance measuring device 100 (processing unit CONT) can accurately perform the contact check.

[0073] Then, the processing unit CONT outputs the final determination result of the goodness determination processing to the output unit OUT as display data Sd. Next, the output unit OUT displays whether the contact resistance (RHC+RLC, RHP+RLP) of the contact portion to be determined is a resistance value smaller than the maximum allowable resistance value based on the display data Sd, that is, displays whether the contact resistance of the contact portion to be determined is good.

[0074] It should be noted that the processing unit CONT can also adopt a configuration in which only the determination results of the determination processing performed multiple times (three times in this example) by the comparators COM1 to COM3 and multiple times (twice in this example) by the comparators COM4 and COM5 are included in the display data Sd and output to the output unit OUT. When this configuration is adopted, the measurer makes a determination based on the determination results of the determination processing.

[0075] Next, when the resistance value of the contact resistance of the contact part of the determination object is good, the processing unit CONT automatically performs the impedance measurement processing of the internal resistance Rx of the battery BAT. In this case, an AC voltage is generated due to the output AC current Io flowing through the inside of the battery BAT. At this time, the generated AC voltage is input to the non-inverting input terminal of the operational amplifier OP1 via the capacitor C2 as the detection voltage Vd2. Next, the first amplifier A1 amplifies the input detection voltage Vd2 at a predetermined amplification factor and outputs it to the filter FIL1. Next, in the filter FIL1, the detection voltage Vd2 output from the first amplifier A1 is input, and the frequency component (noise component) outside the passband included in the detection voltage Vd2 is removed, and the AC voltage as the frequency component of the frequency f1, f2, f3, and f4 included in the detection voltage Vd2 is passed as the detection voltage Vd2. Then, the detection voltage Vd2 as the frequency component of the frequency f1, f2, f3, and f4 that has passed through the filter FIL1 is input to the synchronous detection circuits SD1 to SD3 and SDR.

[0076] At this time, the synchronous detection circuit SDR performs synchronous detection on the input detection voltage Vd2 using the synchronous signal Sf4 output from the AC current source SS2, and outputs a voltage VR whose voltage value changes according to the voltage value (for example, amplitude) of the AC voltage of the output AC current Io based on the frequency f4 in the AC voltage constituting the detection voltage Vd2. Then, the voltage VR output from the synchronous detection circuit SDR is input to the low-pass filter LPFR, and the AC component is removed and smoothed, thereby outputting the DC voltage VR to the A / D converter AD1. Next, the A / D converter AD1 performs A / D conversion on the voltage VR output from the low-pass filter LPFR, and outputs the voltage signal SR to the processing unit CONT. In this case, the voltage VR is a voltage obtained by detecting the voltage generated between the sensing terminal Hp and the sensing terminal Lp based on the output AC current Io with a frequency f4 (that is, the magnitude of the AC voltage corresponding to the frequency f4 of the output AC current Io) in the voltage included in the detection voltage Vd2, so the voltage value becomes a value proportional to the internal resistance Rx of the battery BAT (∝Rx). Therefore, the voltage signal SR becomes a measured value indicating a value proportional to the internal resistance Rx of the battery BAT.

[0077] Next, the processing unit CONT divides the measured value indicated by the voltage signal SR by the known current value of the output AC current Io to calculate the internal resistance Rx of the battery BAT. Then, the processing unit CONT displays the internal resistance Rx of the battery BAT on the output unit OUT by outputting the display data Sd.

[0078] Thus, according to the impedance measuring device 100, the processing unit CONT performs goodness determination processing for each frequency f1, f2, and f3, and performs goodness determination processing for each frequency f4 and f5, similarly to the contact resistance measuring device 1. Thus, even when noise having a frequency that is the same as or close to one or more frequencies (for example, the frequencies f1 and f5) is generated in the environment surrounding the impedance measuring device 100, it does not affect the contact check based on other frequencies (in this example, the frequencies f2, f3, and f4), so that the impedance measuring device 100 (processing unit CONT) can accurately perform the contact check, and as a result, the reliability of the impedance measurement can be sufficiently improved.

[0079] In addition, according to the impedance measuring device 100, since different frequencies and the same number of synchronous detection circuits (synchronous detection circuits SD1 to SD3 and low-pass filters LPF1 to LPF3) are used, the processing for determining whether each different frequency is good or not performed by the processing unit CONT can be performed extremely quickly, as with the contact resistance measuring device 1. As a result, the impedance measurement time can be substantially shortened.

[0080] Furthermore, according to the impedance measuring device 100, the AC current source SS2 also functions as a first AC current source, and supplies the output AC current Io as the measuring AC current as one of a plurality of output AC currents Io as the contact determination AC current having different frequencies f4 and f5 to a current path including the source terminal Hc and each contact portion between the positive terminal T1 at one end of the battery BAT to be measured and the negative terminal T2 at the other end. Therefore, according to the impedance measuring device 100, the second AC current source also functions as the first AC current source for supplying the contact determination AC current, so there is no need to provide two first AC current sources, and as a result, the impedance measuring device 100 can be simply configured and the impedance measuring device 100 can be configured inexpensively.

[0081] Furthermore, according to the impedance measuring device 100, when the processing unit CONT finally determines that the contact resistance of the determination target contact portion is good, the internal resistance Rx of the battery BAT measured by the measuring unit (the measuring unit MU and the processing unit CONT) is output to the output unit OUT. Therefore, according to the impedance measuring device, the reliability of the impedance measurement can be sufficiently improved.

[0082] Next, refer to Figure 3 An impedance measuring device 100A as another impedance measuring device will be described. It should be noted that the same reference numerals are given to the same components as those of the impedance measuring device 100, and duplicate descriptions are omitted.

[0083] The impedance measuring device 100A is configured to include a synchronous detection unit SDU3 instead of the synchronous detection unit SDU2 in the impedance measuring device 100, and to omit the arrangement of the comparator COM5. In this case, the synchronous detection unit SDU3 is configured to include a switch SW1, a synchronous detection circuit SD4, and a low-pass filter LPF4. In addition, in the impedance measuring device 100A, the processing unit CONT sequentially performs switching control of the switch SW1 and output switching control of the threshold voltages Vth4 and Vth5 of the comparator COM4 in conjunction with the switching control of the switch SW1.

[0084] The switch SW1 is configured to include a COM (common) contact, an a contact, and a b contact, and switches between the connection between the COM contact and the a contact and the connection between the COM contact and the b contact according to the switching control of the processing unit CONT. In this case, the synchronization signal Sf4 from the AC current source SS2 is input to the a contact, and the synchronization signal Sf5 from the AC current source SS2 is input to the b contact. In addition, the COM contact of the switch SW1 is connected to the input part of the synchronization signal of the synchronous detection circuit SD4. Therefore, the switch SW1 outputs either the synchronization signal Sf4 or the synchronization signal Sf5 to the synchronous detection circuit SD4 according to the switching control of the processing unit CONT.

[0085] Furthermore, the comparator COM4 performs synchronous detection on the detection voltage Vd3 in sequence using synchronization signals Sf4 and Sf5 of frequencies f4 and f5 which are respectively the same as the frequencies f4 and f5 which are different from the detection voltage Vd3, thereby sequentially outputting voltages V4 and V5 of DC voltages whose voltage values ​​change respectively according to the voltage values ​​of the detection voltage Vd3 corresponding to the different frequencies f4 and f5. Specifically, when the threshold voltage Vth4 is output from the processing unit CONT to the inverting terminal, the comparator COM4 outputs a high (high voltage) determination signal S4 when the voltage V4 output from the low-pass filter LPF4 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth4. On the other hand, when the threshold voltage Vth5 is output from the processing unit CONT to the inverting terminal, the voltage V5 output from the low-pass filter LPF4 and input to the non-inverting input terminal exceeds the voltage value of the threshold voltage Vth5, the comparator COM4 outputs a high (high voltage) determination signal S4.

[0086] Next, the operation of the impedance measurement device 100A will be described. It should be noted that for the same operations as those of the contact resistance measurement device 1 and the impedance measurement device 100 described above, duplicate descriptions will be omitted.

[0087] In the impedance measuring device 100A, when performing the process for determining whether the contact part of the determination object is good or not, the processing unit CONT performs switching control on the switch SW1, and performs output switching control on the threshold voltages Vth4 and Vth5 of the comparator COM4 in conjunction with the switching control. Specifically, when the processing unit CONT performs connection control (hereinafter also referred to as "connection control A") for connecting the COM contact to the a contact on the switch SW1, the threshold voltage Vth4 is output to the comparator COM4. In this case, the synchronization signal Sf4 output from the AC current source SS2 is output to the synchronous detection circuit SD4 via the a contact and the COM contact of the switch SW1. At this time, the synchronous detection circuit SD4 performs synchronous detection on the input detection voltage Vd3 using the synchronization signal Sf4, and outputs a voltage V4 whose voltage value changes according to the voltage value (for example, amplitude) of the AC voltage of the output AC current Io based on the frequency f4 in the AC voltage constituting the detection voltage Vd3. Then, the voltage V4 output from the synchronous detection circuit SD4 is input to the low-pass filter LPF4, and the AC component is removed and smoothed, thereby outputting the DC voltage V4 to the non-inverting terminal of the comparator COM4. Next, as a part of the goodness determination process, the comparator COM4 compares the voltage V4 input to the non-inverting terminal with the threshold voltage Vth4 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S4 when the voltage V4 exceeds the voltage value of the threshold voltage Vth4, and outputting a low (low voltage) determination signal S4 to the processing unit CONT when the voltage V4 is less than the voltage value of the threshold voltage Vth4.

[0088] On the other hand, when the processing unit CONT sequentially performs connection control (hereinafter also referred to as "connection control B") for connecting the COM contact to the b contact on the switch SW1 after the execution of the connection control A, the threshold voltage Vth5 is output to the comparator COM4. In this case, the synchronization signal Sf5 output from the AC current source SS2 is output to the synchronous detection circuit SD4 via the b contact and the COM contact of the switch SW1. At this time, the synchronous detection circuit SD4 performs synchronous detection on the input detection voltage Vd3 using the synchronization signal Sf5, and outputs a voltage V5 whose voltage value varies according to the voltage value (for example, amplitude) of the AC voltage of the output AC current Io based on the frequency f5 in the AC voltage constituting the detection voltage Vd3. Then, the voltage V5 output from the synchronous detection circuit SD4 is input to the low-pass filter LPF4, and the AC component is removed and smoothed, thereby outputting the DC voltage V5 to the non-inverting terminal of the comparator COM4. Next, as part of the goodness determination process, the comparator COM4 compares the voltage V4 input to the in-phase terminal with the threshold voltage Vth5 input to the inverting terminal, thereby outputting a high (high voltage) determination signal S5 when the voltage V5 exceeds the voltage value of the threshold voltage Vth5, and outputting a low (low voltage) determination signal S4 to the processing unit CONT when the voltage V5 is below the voltage value of the threshold voltage Vth5.

[0089] Next, the processing unit CONT performs a goodness determination process at each of the different frequencies f4 and f5 based on the input determination signals S4 and S5. Specifically, the processing unit CONT performs a final determination on whether the contact resistance of the determination target contact portions between the source terminal Hc and the positive terminal T1 of the battery BAT and between the source terminal Lc and the negative terminal T2 of the battery BAT is good or not, similar to the goodness determination process performed by the impedance measuring device 100, based on the result of the comparison of the voltage V4 and the threshold voltage Vth4 by the comparator COM4 when the connection control A is performed (the determination process as a part of the goodness determination process) and the result of the comparison of the voltage V5 and the threshold voltage Vth5 by the comparator COM4 when the connection control B is performed (the determination process as a part of the goodness determination process).

[0090] Then, the processing unit CONT outputs the final determination result of the goodness determination processing to the output unit OUT as display data Sd. Next, the output unit OUT displays whether the contact resistance (RHC+RLC, RHP+RLP) of the contact portion to be determined is a resistance value smaller than the maximum allowable resistance value based on the display data Sd, that is, displays whether the contact resistance of the contact portion to be determined is good.

[0091] Next, when the resistance value of the contact resistance of the determination target contact portion is good, the processing unit CONT performs impedance measurement processing of the internal resistance Rx of the battery BAT and output control of outputting the display data Sd to the output unit OUT, similarly to the impedance measurement device 100 .

[0092] Thus, according to the impedance measuring device 100A, the processing unit CONT performs the goodness determination process for each frequency f1, f2, 3, and performs the goodness determination process for each frequency f4, f5, similarly to the impedance measuring device 100. Thus, even when noise having a frequency that is the same as or close to one or more frequencies (e.g., the frequencies f1 and f5) is generated in the environment surrounding the impedance measuring device 100A, it does not affect the contact check based on other frequencies (in this example, the frequencies f2, f3, and f4), so that the impedance measuring device 100A (processing unit CONT) can accurately perform the contact check, and as a result, the reliability of the impedance measurement can be sufficiently improved.

[0093] In addition, in the impedance measuring device 100A (contact resistance measuring device 1), the synchronous detection unit SD3 is constituted by using one switch SW1 and one synchronous detection circuit constituted by a synchronous detection circuit SD4 and an LPF, and the synchronous detection unit SD3 sequentially performs synchronous detection on the detection voltage Vd3 using synchronous signals Sf4 and Sf5 of the same frequency as the different frequencies f4 and f5 of the detection voltage Vd3, thereby sequentially outputting voltages V4 and V5 whose voltage values ​​change respectively according to the voltage values ​​of the detection voltage Vd3 corresponding to the different frequencies f4 and f5, and the processing unit CONT performs the goodness determination processing for each different frequency f4 and f5. Therefore, according to the impedance measuring device 100A, compared with the synchronous detection unit constituted by a plurality of synchronous detection circuits provided one-to-one corresponding to the different frequencies f4 and f5, the synchronous detection unit SDU3 can be simply constituted and the synchronous detection unit SDU3 can be constituted at a low cost.

[0094] It should be noted that in the impedance measuring device 100, 100A, the AC current source SS2 synthesizes and outputs the output AC currents Io of different frequencies f4 and f5, but is not limited to this configuration, and may also adopt a configuration in which the output AC current Io of the frequency f4 and the output AC current Io of the frequency f5 are not synthesized and sequentially outputted in synchronization with the switching control of the switch SW1 according to the switching control of the processing unit CONT. In addition, in the impedance measuring device 100, 100A, the AC current source SS2 that outputs the output AC current Io of the frequency f4 that is used as both the measurement AC current and the contact determination AC current is described as an example, but the frequency of the contact determination AC current and the frequency of the measurement AC current may be set to different frequencies. However, according to the configuration of the measurement AC current and the contact determination AC current, the AC current source SS2 (the first AC signal power source and the second AC signal power source) can be configured simply and inexpensively.

[0095] In the impedance measuring devices 100 and 100A, both the current path including the contact parts between the source terminals Hc and Lc and the positive terminal T1 and the negative terminal T2 of the battery BAT and the current path including the contact parts between the sense terminals Hp and Lp and the positive terminal T1 and the negative terminal T2 of the battery BAT are used as the determination target contact parts, but the present invention is not limited to this. As an impedance measuring device, although the accuracy of the contact check is reduced, it is also possible to adopt a configuration in which each contact part in one of the current paths is used as the determination target contact part to perform the goodness determination process.

[0096] In addition, as a process for determining whether it is good or not, an example is described in which the processing unit CONT finally determines the contact resistance of the contact part of the determination object as good when it is determined to be good in more than half of the three determination processes, and an example in which the contact resistance of the contact part of the determination object is finally determined to be bad when it is determined to be bad in all determination processes, but it is not limited to this. Although the accuracy of the contact check is reduced, for example, when performing an even number of good or not determination processes, the processing unit CONT can also finally determine the contact resistance of the contact part of the determination object as good when it is determined to be good in more than half of the even number of determination processes. In addition, when it is determined to be good in more than one predetermined number of determination processes, the processing unit CONT can also finally determine the contact resistance of the contact part of the determination object as good. By making such a determination, the contact check can be performed even when noise is generated in a wider frequency domain in the environment surrounding the contact resistance measuring device 1.

[0097] In addition, the contact resistance measuring device is not limited to being used in impedance measuring devices. For example, the contact resistance measuring device can be widely used in measuring devices such as ammeters, voltmeters, power meters, and resistance meters that need to determine whether the contact part of the contact object is good when the contact object is contacted with a terminal, a probe, etc., and power devices that supply current and apply voltage. In addition, for the impedance measuring device, the measurement object is not limited to the battery BAT, and all objects with internal resistance Rx can be used as the measurement object.

[0098] In addition, an example in which the filter FIL1, synchronous detection units SDU1, SUD2, SUD3, comparators COM1 to COM5, low-pass filter LPFR and A / D converter AD1 are separately configured from the processing unit CONT is described, but the processing unit CONT can also perform some or all of the functions of these components through digital processing.

[0099] Industrial Applicability

[0100] According to the invention of the present application, in a contact resistance measuring device having a processing unit that performs a process for determining whether the contact part of the determination object is good, multiple contact determination alternating currents with different frequencies are supplied to a current path including the contact part of the determination object, and the processing unit performs a process for determining whether the contact part is good at each different frequency, thereby accurately performing a contact check. In addition, an impedance measuring device having such a contact resistance measuring device can fully improve the reliability of impedance measurement. Therefore, the invention of the present application can be widely applied to such a contact resistance measuring device, an impedance measuring device that performs impedance measurement, and the like.

[0101] Description of Reference Numerals

[0102] 1: Contact resistance measuring device;

[0103] 100, 100A: Impedance measuring device;

[0104] A1: first amplifier;

[0105] A2: Second amplifier;

[0106] AD1: A / D conversion circuit;

[0107] BAT: battery;

[0108] COM1~COM5: comparator;

[0109] CONT: Processing Department;

[0110] FIL1: filter;

[0111] Hc, Lc: source terminals;

[0112] Hp, Lp: sensing terminals;

[0113] Ij: current used for determination;

[0114] Io: output AC current;

[0115] LPF1~LPF5, LPFR: low-pass filter;

[0116] OUT: output part;

[0117] RHC, RLC, RHP, RLP: contact resistance;

[0118] Rx: internal resistance;

[0119] S1~S5: judgment signal;

[0120] SD1~SD5: synchronous detection circuit;

[0121] Sf1~Sf5: synchronization signal;

[0122] SS1, SS2: AC current source;

[0123] V1~V5: voltage;

[0124] Vd1~Vd3: detection voltage;

[0125] Vth1~Vth5: threshold voltage;

[0126] T1: positive terminal;

[0127] T2: Negative terminal.

Claims

1. A contact resistance measuring device, comprising: A first alternating current source supplies an alternating current for contact determination to a current path including a contact portion of a determination object; A synchronous detection unit performs synchronous detection on the AC voltage using a synchronous signal having the same frequency as the AC voltage, thereby outputting a DC voltage whose voltage value varies according to the voltage value of the AC voltage, wherein: The AC voltage corresponds to the frequency of the contact determination AC current and is generated at the determination target contact portion when the contact determination AC current is supplied from the first AC current source; as well as a processing unit that performs a process for determining whether the contact portion of the determination target is good or not based on the DC voltage output from the synchronous detection unit, In the contact resistance measuring device, The first alternating current source is configured to supply a plurality of contact determination alternating currents having different frequencies to the current path. The synchronous detection unit synchronously detects each of the AC voltages using the synchronization signal having the same frequency as the different frequencies of each of the AC voltages, thereby outputting the DC voltage whose voltage value varies according to the voltage value of each of the AC voltages corresponding to the different frequencies, wherein each of the AC voltages is generated at the contact portion of the determination object when the multiple contact determination AC currents are supplied to the current path, The processing unit executes the quality determination process for each of the different frequencies.

2. The contact resistance measuring device according to claim 1, wherein: The first alternating current source is configured to synthesize the plurality of contact determination alternating currents having different frequencies and supply the synthesized alternating currents to the current path. The synchronous detection unit is configured to include a plurality of synchronous detection circuits provided in one-to-one correspondence with the different frequencies. The plurality of synchronous detection circuits respectively perform synchronous detection on the AC voltage using the synchronization signal having the same frequency as the frequency of the AC voltage, thereby respectively outputting the DC voltage whose voltage value varies according to the voltage value of the AC voltage corresponding to the frequency, wherein the AC voltage is an AC voltage having a frequency corresponding one-to-one to the different frequencies, The processing unit executes the quality determination process for each of the different frequencies.

3. The contact resistance measuring device according to claim 1, wherein: The synchronous detection unit synchronously detects the AC voltages in sequence using a synchronous signal having the same frequency as the different frequencies of the AC voltages, thereby sequentially outputting DC voltages whose voltage values ​​vary according to the voltage values ​​of the AC voltages corresponding to the different frequencies. The processing unit executes the quality determination process for each of the different frequencies.

4. The contact resistance measuring device according to claim 1, wherein: As the processing for determining whether the contact resistance is good, the processing unit performs the following determination processing at each of the different frequencies: when the contact resistance of the contact portion of the determination object is less than a predetermined resistance value, the contact resistance of the contact portion of the determination object is set to be good; when the processing unit determines that the contact resistance is good more than half of the times of the executed determination processing, the contact resistance of the contact portion of the determination object is finally determined to be good.

5. The contact resistance measuring device according to claim 1, wherein: As the processing for determining whether the contact resistance is good or not, the processing unit performs the following determination processing at each of the different frequencies: when the contact resistance of the contact portion of the determination object is less than a predetermined resistance value, the contact resistance of the contact portion of the determination object is set to be good; when the processing unit determines that the contact resistance is poor in all the determination processings performed, the contact resistance of the contact portion of the determination object is finally determined to be poor.

6. An impedance measuring device, comprising: a second AC current source, supplying an AC current for measurement to a measurement object, one end and the other end of the measurement object being connected to source terminals on the Hi side and the Lo side, respectively; and a measuring unit, measuring an AC voltage generated between the one end and the other end of the measurement object when the measurement AC current is supplied, through sensing terminals for signal detection on the Hi side and the Lo side, and measuring the impedance of the measurement object based on the voltage value of the measured AC voltage and the current value of the measurement AC current, wherein: The sensing terminals for signal detection on the Hi side and the Lo side are connected to the one end and the other end, respectively. In the impedance measuring device, A device for measuring contact resistance according to any one of claims 1 to 5, The first alternating current source supplies the contact determination alternating current to at least one of the current paths including the contact locations between the source terminals and the one end and the other end of the measurement object and the current paths including the contact locations between the sense terminals and the one end and the other end of the measurement object. The processing unit executes the goodness determination process using the contact portions in the at least one current path as the determination target contact portions for each of the different frequencies.

7. The impedance measuring device according to claim 6, wherein: The second AC current source also functions as the first AC current source, supplying the measuring AC current as one of the multiple contact determination AC currents with different frequencies to the current path including each source terminal and each contact portion between the one end and the other end of the measuring object.

8. The impedance measuring device according to claim 6, wherein: The impedance measuring device comprises the contact resistance measuring device according to claim 4 as the contact resistance measuring device, The processing unit outputs the impedance of the measurement target measured by the measuring unit when the contact resistance of the determination target contact portion is finally determined to be good.

9. The impedance measuring device according to claim 6, wherein: The impedance measuring device comprises the contact resistance measuring device according to claim 5 as the contact resistance measuring device, The processing unit outputs the impedance of the measurement target measured by the measuring unit when the contact resistance of the determination target contact portion is finally determined to be good.

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