JP2006071306A - Battery characteristics measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery characteristics measuring apparatus capable of speedily starting measurement on electrical parameters of low-voltage batteries and measuring in a short time. <P>SOLUTION: The battery characteristics measuring apparatus is provided with an AC constant current source 2 constituted in such a way as to establish DC connection to a probe 3 for current supply for supplying an AC constant current for a battery 41 via the probe 3 for current supply; buffers 10 and 11 constituted in such a way as to establish DC connection to probes 5 and 6 for voltage detection for inputting a voltage of the battery 51 via the probes 5 and 6 for voltage detection; filters 12 and 13 for removing a DC component form signals outputted from the buffers 10 and 11; and a control unit 19 (measuring part) for measuring electrical parameters of the battery 41 on the basis of an AC voltage of signals passed though the filters 12 and 13 and an AC current (It) passing through the battery 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery characteristic measuring apparatus for measuring electric parameters of a battery.

  As this type of battery characteristic measuring apparatus, an impedance measuring apparatus disclosed in Utility Model Registration No. 3003659 is known. This impedance measuring apparatus is configured to measure the measurement object based on an AC voltage generator constituting an AC power source together with a transformer, an AC current flowing through the measurement object such as a battery having an internal electromotive force, and an AC voltage generated in the measurement object. An impedance measurement circuit that measures impedance, and a voltage correction circuit that detects an internal electromotive force (DC voltage) of the measurement object and adds a corrected DC voltage of the opposite polarity to the detected DC voltage to the AC voltage, Impedance can be measured without causing a DC discharge current to flow out of the measurement object. In this impedance measuring apparatus, when the AC voltage generator outputs an AC voltage to the measurement object via the transformer, the voltage correction circuit adds the corrected DC voltage to the AC voltage. Therefore, according to this impedance measuring apparatus, it is possible to measure the impedance of the measurement object while outputting to the measurement object an AC voltage on which a DC voltage equal to the internal electromotive force of the measurement object is superimposed. As a result of avoiding the problem that the measured impedance becomes unstable due to the discharge current flowing from the object to the transformer (AC power supply), the impedance can be accurately measured. Yes.

  However, the above impedance measuring apparatus has a problem that the impedance measuring circuit and the voltage correcting circuit may be destroyed when a high voltage battery is connected. Further, in this impedance measuring device, since the impedance measuring circuit detects a voltage in which an AC voltage is superimposed on a DC voltage and measures the impedance based on an AC component corresponding to the AC voltage of the detected voltage, When the AC component is a minute voltage, the AC component contained in the detected voltage becomes relatively small and the AC component detection accuracy deteriorates, so that it is difficult to accurately measure the impedance. There is a point. Therefore, as a battery characteristic measuring device capable of measuring battery characteristics with high accuracy without causing damage to the device even if a high voltage battery is connected without causing a discharge current to flow from the battery (battery) to the AC power source, The applicant has developed a battery characteristic measuring apparatus 101 shown in FIG. This battery characteristic measuring apparatus 101 includes current supply probes 3 and 4, voltage detection probes 5 and 6, an I / V converter 7, filters 8 and 9, a differential amplifier 14, and an A / D converter 15. 16, AC constant voltage source 102, control unit 103, and capacitor C1.

  In this battery characteristic measuring apparatus 101, the AC constant voltage source 102 outputs an AC voltage for testing (AC signal) having a frequency of, for example, 1 kHz to the measurement target battery 41 via the capacitor C <b> 1 and the probe 3. It is supplied to the battery 41. The I / V converter 7 includes an operational amplifier 21 and a resistor R3. The I / V converter 7 performs current / voltage conversion on the input alternating current It and outputs an alternating voltage Vi. Capacitor C <b> 1 is connected between probe 3 and AC constant voltage source 102 to prevent the DC voltage of battery 41 from being output to AC constant voltage source 102.

  The filter 8 is configured as a CR-type filter using the capacitor C101 and the resistor R101, and inputs the voltage generated at one electrode of the battery 41 via the probe 5 and removes a direct current component to generate an alternating current. The component (frequency component of AC voltage for inspection) is output. Similarly, the filter 9 is configured as a CR-type filter using the capacitor C102 and the resistor R102, and the voltage generated at the other electrode of the battery 41 is input via the probe 6 and a direct current component is input. Remove AC component (frequency component of AC voltage for inspection). Each of the resistors R101 and R102 is sufficiently larger than the contact resistance, for example, 100 kΩ or more (for example, 100 kΩ) so that the influence of the contact resistance between the battery 41 and the probes 5 and 6 on the measured value can be ignored. High resistance value is specified. On the other hand, the capacitors C101 and C102 are defined to have a capacitance value of 2.2 nF, for example, that allows the filters 8 and 9 to pass an AC component.

  The differential amplifier 14 receives the AC components output from the filters 8 and 9 and differentially amplifies them. Thereby, the differential amplifier 14 generates an AC voltage (AC component of the inter-terminal voltage Vb) generated between the electrodes of the battery 41 due to the AC current It flowing to the battery 41 due to the output of the test AC voltage. AC voltage Va proportional to is output. The A / D converter 15 samples the AC voltage Va output from the differential amplifier 14 at a predetermined sampling period and performs analog / digital conversion (A / D conversion) to output voltage data Dv. The A / D converter 16 A / D converts the AC voltage Vi output from the I / V converter 7 at a predetermined sampling period, and outputs current data Di. The control unit 103 calculates the effective resistance of the battery 41 based on the voltage data Dv and the current data Di.

In the battery characteristic measuring apparatus 101, the capacitor C1 connected between the probe 3 and the AC constant voltage source 102 prevents the voltage of the battery 41 from being output to the AC constant voltage source 102. Capacitors C <b> 101 and C <b> 102 respectively connected between the differential amplifier unit 14 prevent the voltage of the battery 41 from being output to the differential amplifier unit 14. Therefore, even when the voltage (DC voltage) of the battery 41 is high, it is possible to prevent voltage breakdown of the AC constant voltage source 102 and the differential amplifier unit 14. Further, the capacitors C101 and C102 (filters 8 and 9) allow only the AC voltage generated in the battery 41 to pass through the differential amplifier section 14. Therefore, the effective resistance of the battery 41 is calculated with high accuracy.
Utility Model Registration No. 3003659 (page 4-6, Fig. 1)

  However, the battery characteristic measuring apparatus 101 has the following problems to be solved. That is, in this battery characteristic measuring apparatus 101, capacitors C1, C101, and C102 are provided in order to prevent the destruction of the AC constant voltage source 102 and the destruction of the differential amplifying unit 14 when the high voltage battery 41 is a measurement target. It is arranged. Therefore, in the battery characteristic measuring apparatus 101, when the battery 41 is set, the capacitors C1, C101, C102 are charged to the DC potential of the battery 41. Therefore, since it is difficult to accurately calculate the effective resistance of the battery 41 until the potential of each terminal of the capacitors C1, C101, and C102 is stabilized, the measurement must be waited until the capacitors C1, C101, and C102 are charged. There is a problem that must be done.

  In order to solve this problem, it is conceivable to reduce the capacity of each capacitor C1, C101, C102 to shorten the time from the setting of the battery 41 to the start of measurement. However, in the battery characteristic measuring apparatus 101, the resistance values of the resistors R101 and R102 are increased so that the influence of the contact resistance between the battery 41 and the probes 5 and 6 on the measured value can be ignored. When the capacitances of the capacitors C101 and C102 are reduced, the impedances of the capacitors C101 and C102 are increased, so that the level superimposed on the signal of the thermal noise generated in the resistors R101 and R102 is further increased. Therefore, in order to stably and accurately calculate the effective resistance of the battery 41, in the averaging process performed by the control unit 103 based on the voltage data Dv and the current data Di, more voltage data Dv and current data Di. Therefore, this configuration takes a long time to calculate the effective resistance of the battery 41. In other words, it takes a long time to calculate the effective resistance of the battery 41. Problems to be solved arise.

  The present invention has been made in view of such a problem, and provides a battery characteristic measuring apparatus that can quickly start measurement of electrical parameters of a low-voltage battery and that can measure in a short time. Main purpose.

  In order to achieve the above object, the battery characteristic measuring device according to claim 1 is configured to be connectable to a current supply unit in a DC manner and supplies an AC constant current to the battery to be measured through the current supply unit. An AC constant current source that is configured to be connected to the voltage detection unit in a DC manner, and a buffer that inputs the voltage of the battery via the voltage detection unit, and a DC component of a signal output from the buffer And a measurement unit that measures an electrical parameter of the battery based on the AC voltage of the signal that has passed through the filter and the AC constant current flowing through the battery. In this case, the “current supply unit” in the present invention includes not only a probe for supplying current but also various supply means such as a wire that can supply current. In addition, the “voltage detection unit” includes not only a voltage detection probe but also various detection means such as a wire that can detect a voltage.

  The battery characteristic measuring device according to claim 2 is the battery characteristic measuring device according to claim 1, wherein the first capacitor connected between the current supply unit and the AC constant current source, and the voltage detection unit. And a second capacitor connected between the buffers, a first switch for short-circuiting the first capacitor, and a second switch for short-circuiting the second capacitor.

  According to a third aspect of the present invention, there is provided the battery characteristic measuring apparatus according to the second aspect, in which the first voltage detecting unit that detects the voltage via the current supply unit and the voltage detecting unit are used. A second voltage detector for detecting a voltage; and controlling the first switch based on the voltage detected by the first voltage detector to short-circuit the first capacitor and the second And a controller that controls the second switch based on the voltage detected by the voltage detector to short-circuit the second capacitor.

  The battery characteristic measuring device according to claim 4 is the battery characteristic measuring device according to claim 3, wherein the measuring unit is based on the AC voltage of the signal that has passed through the filter and the AC constant current flowing through the battery. The effective resistance of the battery is measured as the electrical parameter, and the voltage detected by one of the first and second voltage detectors is measured as the battery voltage of the battery.

  According to the battery characteristic measuring apparatus of claim 1, the AC constant current source configured to be connectable to the current supply unit in a DC manner and the buffer configured to be connected to the voltage detection unit in a DC manner. Therefore, when measuring a battery having a reference voltage or lower, an AC constant current immediately flows stably and stably to the battery as compared with the conventional battery characteristic measuring apparatus 101 that requires a capacitor charging time. Since the voltage between the terminals is immediately and stably output to the buffer, the measurement of the electric parameter of the battery can be started quickly. Further, by providing a filter that removes the DC component of the signal output from the buffer, a high level of thermal noise is generated in the signal that is formed by the resistors R101 and R102 having high resistance values and the capacitors C101 and C102 having high impedance. Compared with the filters 8 and 9 of the conventional battery characteristic measuring apparatus 101 that superimposes the above, the impedance of the resistor and the capacitor constituting the filter can be defined to be low. For this reason, the level of the thermal noise superimposed on the signal that has passed through the filter can be sufficiently reduced. Therefore, even if the integration time is shortened, the measured value can be measured stably and accurately, so that the electrical parameters of the battery can be measured in a sufficiently short time.

  According to the battery characteristic measuring apparatus of claim 2, the current supply unit is connected to the AC constant current source via the first capacitor, the voltage detection unit is buffer-connected via the second capacitor, When a battery having a voltage at which the AC constant current source and the buffer are not likely to be destroyed is measured by one switch short-circuiting the first capacitor and the second switch short-circuiting the second capacitor, The first and second capacitors can be short-circuited by the first and second switches, and the electric parameters of the battery can be measured in a sufficiently short time. In addition, when measuring a battery having a voltage that may cause the AC constant current source and the buffer to be destroyed, the first and second capacitors are not short-circuited in the same manner as the conventional battery characteristic measuring apparatus 101. Although it takes a little time for measurement, the electric parameters of the battery can be measured without destroying the AC constant current source and the buffer.

  According to the battery characteristic measuring apparatus of claim 3, the control unit controls the first switch based on the voltage detected by the first voltage detection unit to short-circuit the first capacitor and the second. By automatically controlling the second switch based on the voltage detected by the voltage detector, the second capacitor is short-circuited to automatically prevent the output of a voltage that may destroy the AC constant current source and the buffer. Therefore, it is possible to reduce labor and time for the operator to switch the first and second switches according to the battery voltage by operating the device, and to reliably prevent destruction of the AC constant current source and the buffer. it can.

  According to the battery characteristic measuring apparatus of claim 4, the measuring unit measures the effective resistance of the battery as an electrical parameter based on the AC voltage of the signal that has passed through the filter and the AC constant current flowing through the battery, and By measuring the voltage detected by one of the first and second voltage detectors as the battery voltage of the battery, it is possible to use either the first or second voltage detector as a battery voltage measuring instrument. The battery voltage can be measured with a simple configuration.

  Hereinafter, the best mode of a battery characteristic measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  Initially, the structure of the battery characteristic measuring apparatus 1 is demonstrated with reference to drawings. In addition, about what has the same function as the component of the battery characteristic measuring apparatus 101, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  As shown in FIG. 1, the battery characteristic measuring apparatus 1 includes an AC constant current source 2, a current supply probe (corresponding to a current supply unit in the present invention, hereinafter also referred to as a probe) 3, 4 and a voltage detection probe ( Corresponding to a voltage detection unit in the present invention, hereinafter also referred to as a probe, 5, 6, I / V converter 7, buffers 10, 11, filters (specifically, high-pass filters) 12, 13, differential amplification unit 14 , A / D converters 15 and 16, voltage detection units 17 and 18, control unit 19, display unit 20, capacitors C1 to C3, resistors R1 and R2, and switches SW1 to SW3. The voltage between terminals in the ion battery is input in a balanced circuit configuration, and the effective resistance of the battery 41 (an example of an electrical parameter in the present invention) can be measured. The capacitor C1 corresponds to the first capacitor in the present invention, and is connected between the probe 3 and the AC constant current source 2. The AC constant current source 2 outputs a test AC current It having a frequency of, for example, 1 kHz to the battery 41 via the probes 3 and 4. Further, since the AC constant current source 2 has a high output impedance, even if the battery 41 is directly connected in a direct current, the AC constant current source 2 outputs the AC current It without causing the discharge current to flow out of the battery 41. The switch SW1 corresponds to the first switch in the present invention, is connected in parallel to the capacitor C1, and is controlled to open and close according to the switching signal Ss1 output from the control unit 19. Specifically, when the switch signal Ss1 is output from the control unit 19, the switch SW1 shifts to a closed state and short-circuits both ends of the capacitor C1, so that the probe 3 and the alternating current can be connected without interposing the capacitor C1. The constant current source 2 is connected in a DC manner. That is, the AC constant current source 2 is configured to be connected to the probe 3 in a DC manner. On the other hand, when the switch signal Ss1 is not output from the control unit 19, the switch SW1 shifts to the open state, thereby connecting the probe 3 and the AC constant current source 2 in a DC manner with the capacitor C1 interposed. Connect in an alternating manner. The I / V converter 7 includes an operational amplifier 21 and a resistor R3 that connects the output terminal and the inverting input terminal of the operational amplifier 21, and receives an alternating current It flowing through the battery 41 via the probe 4. Then, an AC voltage Vi is generated and output by current / voltage conversion. In this case, the I / V converter 7 generates an alternating voltage Vi that has a voltage value of It × R3, where It is the current value of the alternating current It and R3 is the resistance value of the resistor R3.

  Probes 5 and 6, capacitors C 2 and C 3, resistors R 1 and R 2, switches SW 2 and SW 3, buffers 10 and 11 and filters 12 and 13 are paired to form a balanced circuit as shown in FIG. . The capacitor C2 corresponds to the second capacitor in the present invention, and is connected between the probe 5 and the buffer 10 and is one of the voltages generated at one electrode of the battery 41 input via the probe 5. The DC component is blocked and the AC component for inspection is passed through the buffer 10. Similarly, the capacitor C3 corresponds to the second capacitor in the present invention, is connected between the probe 6 and the buffer 11, and is generated at the other electrode of the battery 41 input via the probe 6. The DC component of the voltage is blocked and the AC component for inspection is passed through the buffer 11. The resistors R1 and R2 are bias resistors for defining the DC potential of each input terminal of the buffers 10 and 11, and the influence of the contact resistance between the battery 41 and the probes 5 and 6 on the measured value can be ignored. Thus, it is specified to a high resistance value, for example, 100 kΩ, which is sufficiently larger than the contact resistance. The capacitor C2 and the resistor R1 constitute a CR type high pass filter. In this case, the capacitor C2 is defined to have a small capacitance value of 2.2 nF, for example, so that the high-pass filter passes the AC component for inspection and the charging time by the battery 41 is shortened. Similarly, the capacitor C3 is also defined to have a small capacitance value of 2.2 nF, for example.

  The switch SW2 corresponds to the second switch in the present invention, is connected in parallel to the capacitor C2, and is controlled to open and close according to the switching signal Ss2 output from the control unit 19. Specifically, when the switch signal Ss2 is output from the control unit 19, the switch SW2 shifts to the closed state and short-circuits both ends of the capacitor C2, so that the probe 5 and the buffer 5 are not interposed without the capacitor C2. 10 is connected in a direct current manner. That is, the buffer 10 is configured to be connectable to the probe 5 in a direct current manner. On the other hand, when the switch signal Ss2 is not output from the control unit 19, the switch SW2 shifts to an open state, thereby interposing the capacitor C2 and connecting the probe 5 and the buffer 10 in a DC manner. Connect to. Similarly, the switch SW3 corresponds to the second switch in the present invention, is connected in parallel to the capacitor C3, and is controlled to open and close according to the switching signal Ss3 output from the control unit 19. Specifically, when the switch signal Ss3 is output from the control unit 19, the switch SW3 shifts to the closed state and shorts both ends of the capacitor C3, thereby preventing the probe 6 and the buffer 6 from interposing the capacitor C3. 11 is connected in a direct current manner. That is, the buffer 11 is configured to be connectable to the probe 6 in a direct current manner. On the other hand, when the switching signal Ss3 is not output from the control unit 19, the switch SW3 shifts to an open state, thereby interposing the capacitor C3 and connecting the probe 6 and the buffer 11 in a DC manner. Connect to.

  The buffer 10 is composed of, for example, an operational amplifier connected as a voltage follower, and a non-inverting input terminal is connected to the capacitor C2 and the resistor R1. Similarly, the buffer 11 is composed of an operational amplifier connected in voltage follower, and a non-inverting input terminal is connected to the capacitor C3 and the resistor R2.

  As an example, the filter 12 is configured as a CR-type high-pass filter using a capacitor C4 and a resistor R4, and blocks a DC component of a signal output from the buffer 10 and outputs an AC component for inspection to the differential amplifying unit 14. To do. Similarly, the filter 13 is configured as a CR-type high-pass filter using the capacitor C5 and the resistor R5 as an example, and blocks the DC component of the signal output from the buffer 11 and differentially amplifies the AC component for inspection. To the unit 14. In this case, the resistors R4 and R5 are defined to have a small resistance value (for example, a resistance value of 1 kΩ) in order to reduce the level of generated thermal noise. The resistors R4 and R5 are also used as bias resistors for defining the DC potential of each input terminal of the differential amplifier section 14. The capacitors C4 and C5 are defined to have a large capacitance value so as to avoid the thermal noise generated by the resistors R4 and R5 from being superimposed at a high level on the signals output from the buffers 10 and 11, and the resistors R4 and R5. The capacitance values are defined so that the AC component for inspection can pass through the filters 12 and 13 together. In this case, the capacitors C4 and C5 are defined to have a capacitance value of 0.22 μF, for example.

On the other hand, the thermal noise (thermal noise voltage density) superimposed on the signal by the filters 8 and 9 and the filters 12 and 13 of the conventional battery characteristic measuring apparatus 101 is the thermal noise superimposed by the filters 8, 9, 12 and 13. The voltage density is Vnp, the resistance values of the resistors R101, R102, R4, and R5 that constitute the filters 8, 9, 12, and 13 are R, and the capacitors C101, C102, and the capacitors that constitute the filters 8, 9, 12, and 13, respectively. When the impedance of C5 and C6 is Zc, it is expressed by the following equation.
Vnp = 0.13 · √ (R) · | Zc / (R + Zc) |
In the battery characteristic measuring apparatus 1, as described above, the resistance values of the resistors R 4 and R 5 in the filters 12 and 13 are compared with the resistance values of the resistors R 101 and R 102 in the conventional filters 8 and 9 (resistance value 100 kΩ). Therefore, it is specified to a sufficiently small value of 1 kΩ. Further, the capacitors C4 and C5 in the filters 12 and 13 have a capacitance value of 0.22 μF which is sufficiently larger than the capacitance values (capacitance value 2.2 nF) of the capacitors C101 and C102 in the conventional filters 8 and 9. It is prescribed. Therefore, the level of thermal noise superimposed by the filters 12 and 13 is such that the resistance values of the resistors R1 and R2 and the impedance values of the capacitors C2 and C3 are respectively 1/100 of the conventional resistance value and impedance value. Compared to a conventional filter, the level is reduced to 1/10.

  The differential amplifying unit 14 differentially amplifies the AC voltage that passes through the filters 12 and 13 and is output between the output terminals of the filters 12 and 13 and outputs the AC voltage Va. The A / D converter 15 samples the AC voltage Va at a sampling period in which the AC component for inspection can be sampled and A / D converts it to output voltage data Dv. For example, the A / D converter 16 samples the AC voltage Vi at the same sampling period as that of the A / D converter 15 and performs A / D conversion to output current data Di.

  The voltage detection unit 17 corresponds to the first voltage detection unit in the present invention, detects the voltage between the probes 3 and 4, and outputs voltage data Dk 1 indicating the detected voltage to the control unit 19. The voltage detector 18 corresponds to the second voltage detector in the present invention, detects the voltage between the probes 5 and 6, and outputs voltage data Dk 2 indicating the detected voltage to the controller 19.

The control unit 19 corresponds to the measurement unit and the control unit in the present invention, and the voltage data Dk1 detected by the voltage detection unit 17 is a preset reference voltage (for example, the allowable values of the AC constant current source 2 and the buffers 10 and 11). It is determined whether or not the voltage exceeds 70% of the input voltage. When it is determined that the voltage does not exceed, the switching signal Ss1 is output and the switch SW1 is shifted to the closed state. Further, the control unit 19 determines whether or not the voltage data Dk2 detected by the voltage detection unit 18 exceeds the preset reference voltage. When it is determined that the voltage data Dk2 does not exceed, the switching signals Ss2 and Ss3 are displayed. Outputs the switches SW2 and SW3 to the closed state. The control unit 19 also determines the effective resistance of the battery 41 (electrical parameters in the present invention) based on the voltage data Dv output from the A / D converter 15 and the current data Di output from the A / D converter 16. Is calculated. When calculating the effective resistance, the control unit 19 obtains voltage data for calculating effective resistance by adding and averaging a predetermined number of voltage data Dv with respect to the voltage data Dv, and the obtained voltage data, for example, for one cycle. The effective resistance is calculated based on the current data Di obtained by averaging the above. In this case, the thermal noise voltage included in the voltage data obtained by averaging is Vn, the thermal noise voltage density included in the voltage data Dv before the averaging is Vnp, and the integration time, that is, a plurality of averages that are added and averaged. When the total time during which voltage data Dv is sampled is Ta, the thermal noise voltage is approximated by the following equation.
Vn≈Vnp · √ (1 / Ta)
For example, the thermal noise voltage density (Vnp) included in the voltage data for calculating effective resistance of the conventional battery characteristic measuring apparatus 101 is set to 1, and the integration time (Ta) of the conventional battery characteristic measuring apparatus 101 is set to 1. Sometimes the thermal noise voltage (Vn) is 1 according to the above equation. In this case, as an example, as described above, the noise voltage density (Vnp) superimposed by the filters 12 and 13 is 1/10 of the noise voltage density superimposed by the filters 8 and 9. Therefore, in order to obtain voltage data for calculating effective resistance with the same thermal noise voltage as the battery characteristic measuring apparatus 101 (in this case, 1), the integration time is about 1/100 of the integration time of the battery characteristic measuring apparatus 101. Can be measured at high speed. That is, the voltage data for calculating the effective resistance can be obtained from the voltage data Dv of about 1/100. For this reason, it can measure in a sufficiently short time.

  When the control unit 19 determines that the voltage data Dk1 and the voltage data Dk2 exceed the preset reference voltage, the control unit 19 stops the output of the switching signals Ss1 to Ss3 and opens the switches SW1 to SW3. By shifting, the capacitor C 1 is connected in series between the probe 3 and the AC constant current source 2, and the capacitors C 2 and C 3 are connected in series between the probes 5, 6 and the buffers 10, 11. Display an overvoltage alarm. In this case, the capacitances of the capacitors C2 and C3 are defined to be small (impedance is large), and the resistance values of the resistors R1 and R2 are defined to be large values. Therefore, since the level of the thermal noise superimposed on the AC voltage Va increases, the control unit 19 increases the number of data of the voltage data Dv to be added and averaged when obtaining voltage data for calculating effective resistance. That is, in order to measure a lot of voltage data Dv, the measurement time becomes long. In addition, the control unit 19 causes the display unit 20 to display the calculated effective resistance.

  Next, the overall operation of the battery characteristic measuring apparatus 1 will be described with reference to the drawings.

  First, the control unit 19 connects the probes 3 to 6 to the battery 41, and the battery voltage of the battery 41 is set in advance based on the voltage data Dk1 and Dk2 output from the voltage detection units 17 and 18. It is determined whether or not it is lower than the voltage. When determining that the voltage is equal to or lower than the reference voltage, the control unit 19 outputs the switching signals Ss1 to Ss3 to close the switches SW1 to SW3. Next, the AC constant current source 2 outputs an AC current It to the battery 41 via the switch SW1 and the probes 3 and 4. At this time, since the capacitor C1 is short-circuited by the switch SW1, the AC current It is immediately stably supplied to the battery 41 without charging the capacitor C1. Accordingly, a voltage (terminal voltage Vb) obtained by adding the DC voltage of the battery 41 and the AC voltage caused by the AC current It is generated between both ends of the battery 41. Subsequently, the I / V converter 7 converts the alternating current It into current / voltage and outputs the alternating voltage Vi. In response to this, the A / D converter 16 A / D converts the AC voltage Vi and outputs current data Di to the control unit 19.

  On the other hand, the buffer 10 inputs the voltage of one electrode of the battery 41 via the probe 5 and the switch SW2, and outputs the input voltage to the filter 12 with low impedance. Similarly, the buffer 11 inputs the voltage of the other electrode of the battery 41 via the probe 6 and the switch SW3, and outputs the input voltage to the filter 13 with low impedance. In this case, since both ends of the capacitors C2 and C3 are short-circuited by the switches SW2 and SW3, the inter-terminal voltage Vb of the battery 41 is immediately input to the buffers 10 and 11 without charging the capacitors C2 and C3. . Further, since the resistance values of the resistors R1 and R2 are sufficiently small, the thermal noise voltage of the resistors R1 and R2 superimposed on the inter-terminal voltage Vb can be suppressed sufficiently small.

  Next, the filter 12 passes only the test AC component to the differential amplifier 14 while removing the DC component of the voltage output from the buffer 10. Similarly, the filter 13 passes only the test AC component to the differential amplifier 14 while removing the DC component of the voltage output from the buffer 11. Subsequently, the differential amplifier 14 differentially amplifies the AC voltages output from the filters 12 and 13, and outputs the AC voltage Va to the A / D converter 15. Next, the A / D converter 15 outputs voltage data Dv obtained by A / D converting the AC voltage Va to the control unit 19. Subsequently, the control unit 19 calculates an effective resistance based on the voltage data Dv and the current data Di. In this case, since the switches SW2 and SW3 are closed, the control unit 19 adds and averages the voltage data Dv having a small number of data to calculate voltage data for calculating effective resistance. Next, the control unit 19 displays the calculated effective resistance of the battery 41 on the display unit 20. Further, the control unit 19 detects the battery voltage of the battery 41 indicated by the voltage data Dk1 output from the voltage detection unit 18 and causes the display unit 20 to display the detected battery voltage. Thus, the measurement of the effective resistance for the battery 41 is completed.

  On the other hand, when the probes 3 to 6 are connected to the high-voltage battery 42, the control unit 19 sets the battery voltage of the battery 41 in advance based on the voltage data Dk1 and Dk2 output from the voltage detection units 17 and 18. It is determined that the specified reference voltage has been exceeded. At this time, the control unit 19 stops the output of the switching signals Ss1 to Ss3 and shifts the switches SW1 to SW3 to the open state, thereby connecting the capacitor C1 in series between the probe 3 and the AC constant current source 2. The capacitors C2 and C3 are connected in series between the probes 5 and 6 and the buffers 10 and 11, respectively, and an overvoltage alarm is displayed on the display unit 20. In this state, the capacitor C <b> 1 prevents direct output of the DC voltage of the battery 42 to the AC constant voltage source 102. Capacitor C <b> 2 prevents direct output of DC voltage to buffer 10 at one electrode of battery 42. Similarly, capacitor C3 prevents direct output of DC voltage to buffer 11 at the other electrode of battery 42. Subsequently, after the charging time for charging the capacitors C1 to C3 to the DC potential of the battery 42 has elapsed, the control unit 19 starts measuring the voltage data Dv and the current data Di. In this case, the capacitors C2 and C3 and the resistors R1 and R2 superimpose high-level thermal noise on the AC voltage to be passed in the same manner as the high-pass filters 8 and 9 of the conventional battery characteristic measuring apparatus 101. For this reason, the control unit 19 increases the number of data of the voltage data Dv to be added and averaged when obtaining the voltage data for calculating the effective resistance.

  As described above, according to the battery characteristic measuring apparatus 1, the AC constant current source 2 connected to the probe 3 in a DC manner and the buffers 10 and 11 connected to the probes 5 and 6 in a DC manner were provided. Therefore, when measuring the battery 41 having a voltage lower than the reference voltage, the alternating current It for inspection flows immediately and stably to the battery 41 as compared with the conventional battery characteristic measuring apparatus 101 that requires charging time of the capacitors C1 to C3. At the same time, the voltage Vb between the terminals of the battery 41 is immediately and stably output to the buffers 10 and 11, so that the effective resistance of the battery 41 can be quickly measured. Furthermore, according to the battery characteristic measuring apparatus 1, by providing the filters 12 and 13 for removing the DC components of the signals output from the buffers 10 and 11, high resistance resistors R101 and R102 and high impedance capacitors are provided. The impedances of the resistors R4 and R5 and the capacitors C4 and C5 that constitute the filters 12 and 13 are lower than those of the conventional filters 8 and 9 that are configured by C101 and C102 and superimpose a high level of thermal noise on the passing signal. Can be prescribed. For this reason, the level of the thermal noise superimposed on the signal that has passed through the filters 12 and 13 can be sufficiently reduced. Therefore, even if the integration time is shortened, the measured value can be measured stably and accurately, so that the effective resistance of the battery 41 can be measured in a sufficiently short time.

  In this battery characteristic measuring apparatus 1, the probe 3 is connected to the AC constant current source 2 via the capacitor C1, and the probes 5 and 6 are connected to the buffers 10 and 11 via the capacitors C2 and C3. Switches SW1 to SW3 that respectively short-circuit both ends of the capacitors C1 to C3 are connected in parallel to the capacitors C1 to C3. Therefore, according to this battery characteristic measuring apparatus 1, when the battery 41 having a reference voltage or less that does not possibly destroy the AC constant current source 2 and the buffers 10 and 11 is to be measured, the switches SW1 to SW3 are closed. Thus, the effective resistance of the battery 41 can be measured in a sufficiently short time. Further, when the battery 42 that exceeds the reference voltage that may destroy the AC constant current source 2 and the buffers 10 and 11 is to be measured, the switches SW1 to SW3 are opened, and the conventional battery characteristic measuring device 101 and Similarly, the effective resistance can be measured without destroying the AC constant current source 2 and the buffers 10 and 11 although the measurement takes a little time.

  Further, in the battery characteristic measuring apparatus 1, the switches SW1 to SW3 are controlled to be closed based on the voltages detected by the voltage detectors 17 and 18, and both ends of the capacitors C1 to C3 are short-circuited. Therefore, according to this battery characteristic measuring apparatus 1, in order to automatically prevent the output of a voltage exceeding the reference voltage that may destroy the AC constant current source 2 and the buffers 10 and 11, an operator operates the apparatus. The labor and time for switching the switches SW1 to SW3 according to the battery voltage can be reduced, and destruction of the AC constant current source 2 and the buffers 10 and 11 can be reliably prevented.

  Further, according to the battery characteristic measuring apparatus 1, either the voltage data Dk 1 detected by the voltage detection unit 17 or the voltage data Dk 2 detected by the voltage detection unit 18 is used as a measured value of the battery voltage of the battery 41. Thus, since the voltage detector 17 or the voltage detector 18 can be used as a battery voltage measuring device, the battery voltage can be measured with a simple configuration.

  Next, the battery characteristic measuring apparatus 1A will be described with reference to FIG. In addition, about what has the same function as the component of the battery characteristic measuring apparatus 101 and the battery characteristic measuring apparatus 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  First, the configuration of the battery characteristic measuring apparatus 1A will be described with reference to the drawings.

  As shown in FIG. 2, the battery characteristic measuring apparatus 1A includes an AC constant current source 2, probes 3 to 6, voltage detection units 17 and 18, display unit 20, filter 25, amplifier circuit 26, lock-in amplifier 27, A / A D converter 28, a control unit 29, capacitors C1 and C2, a resistor R1, and switches SW1 and SW2, and a voltage between terminals of the battery 41 to be measured is input in an unbalanced circuit configuration. The resistance can be measured.

  The filter (specifically, the high-pass filter) 25 constitutes a buffer and a filter according to the present invention, and also functions as a buffer, a high-pass filter, and an amplifier, and a DC component is obtained from a voltage input via the switch SW2 or the capacitor C2. While being removed, the AC component for inspection is amplified and output to the amplifier circuit 26. In addition, the filter 25 includes, as an example, a non-inverting amplifier circuit that includes an operational amplifier 31, a capacitor C6, and resistors R6 and R7. The operational amplifier 31 has a switch SW2, a capacitor C2, and a resistor R1 connected to its high impedance non-inverting input terminal. A resistor R6 is connected between the output terminal and the inverting input terminal of the operational amplifier 31, and a resistor R7 and a capacitor C6 connected in series are connected between the inverting input terminal and the ground GND. The resistor R6 is defined to have a higher resistance value (for example, a resistance value of 100 kΩ) than the resistor R7, and defines the gain of the filter 25 together with the resistor R7. The resistor R7 is defined to have a small resistance value (for example, a resistance value of 1 kΩ) in order to reduce the level of thermal noise superimposed on the signal output from the differential amplifier 31. In this case, the level of thermal noise generated by the resistors R6 and R7 is equal to the level of thermal noise generated by the equivalent resistance when the resistors R6 and R7 are connected in parallel. Therefore, since the resistance R7 has a small resistance value, the equivalent resistance also has a small resistance value (in this case, about 1 kΩ), and the level of the thermal noise superimposed on the output signal is sufficiently low.

  The amplifier circuit 26 is an amplifier having a function of a high-pass filter. The amplifier circuit 26 amplifies the AC component for inspection from the signal output from the filter 25 and outputs it to the lock-in amplifier 27. Specifically, as an example, the amplifier circuit 26 includes an inverting amplifier circuit including an operational amplifier 32, a capacitor C7, and resistors R8 and R9. A resistor R9 is connected between the output terminal and the inverting input terminal of the operational amplifier 32, and a resistor R8 and a capacitor C7 connected in series are connected to the non-inverting input terminal. The resistor R9 is defined to have a higher resistance value (for example, a resistance value of 100 kΩ) than the resistor R8, and defines the gain of the amplifier circuit 26 together with the resistor R8. The resistor R8 is defined to have a small resistance value (for example, a resistance value of 1 kΩ) in order to reduce the level of thermal noise superimposed on the signal output from the operational amplifier 32. In this case, the level of thermal noise generated by the resistors R8 and R9 is equal to the level of thermal noise generated by the equivalent resistance when the resistors R8 and R9 are connected in parallel. Therefore, since the resistance value of the resistor R8 is small, the equivalent resistance also becomes a small resistance value (in this case, about 1 kΩ), and the level of thermal noise superimposed on the output signal is sufficiently low.

  The lock-in amplifier 27 generates a voltage Vr indicating an effective resistance based on the signal output from the amplifier circuit 26 and the current value of the reference signal Is having a constant current equal to the AC current It output from the AC constant current source 2. Output to the A / D converter 28. The A / D converter 28 samples the voltage Vr at a predetermined sampling period and performs A / D conversion to output effective resistance data Dr indicating the voltage Vr to the control unit 29.

  The control unit 29 calculates the effective resistance based on the effective resistance data Dr output from the A / D converter 28 and causes the display unit 20 to display the measured effective resistance. In calculating the effective resistance, the control unit 29 calculates the effective resistance by adding and averaging a predetermined number of effective resistance data Dr when the switches SW1 and SW2 are in the closed state. Further, when the switches SW1 and SW2 are in the open state, the level of the thermal noise included in the voltage Vr is high, so that the control unit 29 increases the number of effective resistance data Dr to be averaged when obtaining the effective resistance. (Make integration time longer)

  Next, the overall operation of the battery characteristic measuring apparatus 1A will be described with reference to the drawings. In addition, description is abbreviate | omitted about the operation | movement similar to the operation | movement of the battery characteristic measuring apparatus 1. FIG.

  When it is determined that the battery voltage of the battery 41 is equal to or lower than the reference voltage, the control unit 29 outputs the switching signals Ss1 and Ss2 and shifts the switches SW1 and SW2 to the closed state. Next, the AC constant current source 2 outputs an AC current It to the battery 41 via the switch SW1 and the probes 3 and 4. At the same time, the AC constant current source 2 outputs the reference signal Is to the lock-in amplifier 27.

  The inter-terminal voltage Vb generated between the electrodes of the battery 41 is input to the filter 25 via the probe 5 and the switch SW2. In this case, since the capacitor C2 is short-circuited by the closed switch SW2, the inter-terminal voltage Vb is immediately input to the filter 25. In this case, the level of thermal noise superimposed on the inter-terminal voltage Vb input to the filter 25 is extremely suppressed. Subsequently, the filter 25 amplifies the test AC component while removing the DC component of the input inter-terminal voltage Vb, and outputs the amplified AC component to the amplifier circuit 26. Also in this case, the level of the thermal noise superimposed on the signal output from the filter 25 is extremely suppressed. Next, the amplifier circuit 26 amplifies the alternating current component for inspection from the signal input from the filter 25 and outputs it to the lock-in amplifier 27. In this case, the thermal noise superimposed on the signal output from the amplifier circuit 26 is suppressed to a low level. Next, the lock-in amplifier 27 outputs the voltage Vr indicating the effective resistance to the A / D converter 28. Subsequently, the A / D converter 28 A / D converts the voltage Vr and outputs effective resistance data Dr to the control unit 29. Next, the control unit 29 calculates the effective resistance by averaging the effective resistance data Dr of a predetermined number of data. Thus, the measurement of the battery 41 is completed.

  On the other hand, when the control unit 29 determines that the battery voltage of the battery 41 exceeds the reference voltage or lower, the control unit 29 stops the output of the switching signals Ss1 and Ss2 in the same manner as the operation of the battery characteristic measuring device 1, and the switch SW1. , SW2 is shifted to the open state, so that the capacitor C1 is connected in series between the probe 3 and the AC constant current source 2, and the capacitor C2 is connected in series between the probe 5 and the filter 25, and the display unit 20 is overvoltaged. The alarm is displayed. Therefore, as in the case of the conventional battery characteristic measuring apparatus 101, the effective resistance of the battery 42 is controlled by the control unit 29 without destroying the AC constant current source 2 and the filter 25, although the time until the measurement starts and the measurement time become longer. And the battery voltage is measured.

  According to the battery characteristic measuring apparatus 1A, the AC constant current source 2 connected to the probe 3 in a DC manner and the filter 25 connected to the probe 5 in a DC manner provide a voltage below a predetermined reference voltage. When measuring the battery 41, compared to the conventional battery characteristic measuring apparatus 101 that requires a capacitor charging time, the alternating current It for testing can be immediately and stably output to the battery 41, and between the terminals of the battery. Since the voltage Vb can be immediately and stably input to the filter 25, the effective resistance of the battery 41 can be quickly measured. In addition, according to the battery characteristic measuring apparatus 1A, since the filter 25 is provided, the conventional filter 8 is configured to include a high-impedance resistor R101 and a capacitor C101 and superimpose a high level of thermal noise on the passing signal. In comparison, the impedances of the resistors R6 and R7 and the capacitor C6 constituting the filter 25 and the resistors R8 and R9 and the capacitor C7 constituting the amplifier circuit 26 can be specified to be low, so that the signal passing through the filter 25 and the amplifier circuit 26 is reduced. The level of thermal noise superimposed on can be suppressed sufficiently low. Therefore, even if the integration time is shortened, the measured value can be measured stably and accurately, so that the effective resistance of the battery 42 can be measured in a sufficiently short time.

  In the battery characteristic measuring apparatus 1A, the probe 3 is connected to the AC constant current source 2 through the capacitor C1, the probe 5 is connected to the filter 25 through the capacitor C2, and both ends of the capacitors C1 and C2 in the closed state. Are respectively connected in parallel to the capacitors C1 and C2. Therefore, according to the battery characteristic measuring apparatus 1A, when the battery 41 having a reference voltage or less that does not possibly destroy the AC constant current source 2 and the filter 25 is connected, the switches SW1 and SW2 are moved to the closed state. The effective resistance of the battery 41 can be measured in a sufficiently short time. Further, when a battery 42 that exceeds a reference voltage that may destroy the AC constant current source 2 and the filter 25 is connected, the switches SW1 and SW2 are opened and the same as in the conventional battery characteristic measuring apparatus 101. Although the measurement requires time, the effective resistance can be measured without destroying the AC constant current source 2 and the filter 25.

  In addition, this invention is not limited to the structure of above-described battery characteristic measuring apparatus 1 and 1A. For example, a configuration is adopted in which the integration time is changed by changing the number of data used when the control units 19 and 29 calculate the effective resistance. Instead of this configuration, the integration time at the time of sampling is converted into an A / D converter. It is possible to adopt a configuration in which the container itself is changed. Moreover, although the structure which displays a warning on the display part 20 was employ | adopted, the structure which outputs a warning sound with this structure or it replaces with this structure is employable. Moreover, although the high-pass filter is employed as the filter in the present invention, a band-pass filter can also be employed. Moreover, although the structure which measures an effective resistance was demonstrated, the structure which measures an impedance (another example of the electrical parameter in this invention) is also employable. In addition, the reference voltage serving as a reference for switching the switch SW1 and the reference voltage serving as a reference for switching the switch SW2 (and SW3) can be set to different voltages.

1 is a configuration diagram showing a configuration of a battery characteristic measuring device 1. FIG. It is a block diagram which shows the structure of 1 A of battery characteristic measuring apparatuses. 1 is a configuration diagram showing a configuration of a battery characteristic measuring apparatus 101. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A Battery characteristic measuring apparatus 2 AC constant current source 3,4 Current supply probe 5,6 Voltage detection probe 10,11 Buffer 12,13,25 Filter 17,18 Voltage detection unit 19,29 Control unit C1-C3 Capacitor SW1 to SW3 switch

Claims (4)

An AC constant current source configured to be connectable to a current supply unit in a DC manner and supplying an AC constant current to the battery to be measured through the current supply unit;
A buffer configured to be connectable to a voltage detection unit in a direct current manner and to input the voltage of the battery via the voltage detection unit;
A filter that removes a DC component of the signal output from the buffer;
A battery characteristic measuring device comprising: a measuring unit that measures an electrical parameter of the battery based on an AC voltage of the signal that has passed through the filter and the AC constant current flowing through the battery. A first capacitor connected between the current supply unit and the AC constant current source;
A second capacitor connected between the voltage detector and the buffer;
A first switch for short-circuiting the first capacitor;
The battery characteristic measuring device according to claim 1, further comprising a second switch that short-circuits the second capacitor. A first voltage detection unit for detecting a voltage via the current supply unit;
A second voltage detector that detects a voltage via the voltage detector;
Based on the voltage detected by the first voltage detector, the first switch is controlled to short-circuit the first capacitor and based on the voltage detected by the second voltage detector. The battery characteristic measuring device according to claim 2, further comprising a control unit that controls the second switch to short-circuit the second capacitor.   The measurement unit measures the effective resistance of the battery as the electrical parameter based on the AC voltage of the signal that has passed through the filter and the AC constant current flowing through the battery, and the first and second voltages. The battery characteristic measuring device according to claim 3, wherein a voltage detected by any one of the detection units is measured as a battery voltage of the battery.

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