Drive measurement circuit, impedance measurement device, impedance measurement system, and drive measurement method

Abstract

A drive measurement circuit (2) comprises: a current measurement unit (21) that measures the current of a first battery (B1) and the current of a second battery (B2); a voltage measurement unit (20) that measures the voltage of the first battery (B1) and the voltage of the second battery (B2); an AC detection unit (22) that receives a measurement instruction signal including information on a measurement frequency from a host system (200) that has a function of calculating the AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency and outputs the AC voltage and the AC current to the host system (200) on the basis of the measurement result of the voltage measurement unit (20) and the measurement result of the current measurement unit (21); and a drive control unit (23) that drives a plurality of switching elements so as to periodically change the movement state of electrical energy via an inductor (14) in accordance with the measurement frequency.

Description

Drive measurement circuit, impedance measurement device, impedance measurement system, and drive measurement method

[0001] The present disclosure relates to a driving measurement circuit and the like for controlling an impedance measurement device that measures the AC impedance of a plurality of batteries connected in series.

[0002] AC impedance is a parameter used to determine the battery condition. The impedance measurement method disclosed in Patent Document 1 superimposes an AC current of a first reference frequency on the battery, measures the battery voltage and current at a sampling frequency significantly higher than the first reference frequency, converts them into digital values, and multiplies each digital value by the first reference frequency signal and a second reference frequency signal (e.g., the first reference frequency signal is a sine wave, and the second reference frequency signal is a cosine wave) that are orthogonal to the first reference frequency signal, thereby converting each digital value into real and imaginary components of a complex voltage and current. The data for each component is further integrated (averaged) to reduce measurement error and retained, and then transmitted to a host system. The host system has a CPU that divides the complex current component from the complex voltage component to calculate the AC impedance, and then sweeps the first reference frequency (a low frequency range from 0.01 Hz to several tens of kHz) to determine the battery condition from the frequency characteristics of the AC impedance.

[0003] One known method for superimposing an AC current having a first reference frequency on a battery is to pass high-frequency pulses of current through the battery at a frequency significantly higher than the first reference frequency, thereby achieving highly efficient superimposition of the AC current. In the impedance measurement device disclosed in Patent Document 2, a switching circuit forming a loop circuit together with the battery generates a high-frequency intermittent current. The switching circuit includes a first switch and a second switch serially inserted in the loop circuit, an inductor and a power storage device serially connected in parallel with the second switch, and a drive controller that controls and drives the first and second switches. The drive controller alternately turns the first and second switches on and off at a predetermined on-duty, thereby allowing a pulse current to flow from the battery to charge the power storage device. By repeating periods of switching operation and periods of no switching operation, the flowing current and the battery voltage are measured, and an AC impedance corresponding to this repetition frequency, i.e., the first reference frequency, is calculated. Furthermore, by passing a pulse current regenerated from the power storage device to the battery, the voltage of the power storage device can be controlled within a predetermined range and changes in battery capacity can be suppressed.

[0004] International Publication No. 2020 / 261799 International Publication No. 2023 / 127478

[0005] However, the method disclosed in Patent Document 2 requires components such as an inductor and a power storage device (capacitor), which poses a problem of increasing the size of the impedance measuring device.

[0006] Therefore, the present disclosure provides a drive measurement circuit and the like that enables the miniaturization of an impedance measurement device.

[0007] A driving and measuring circuit according to one aspect of the present disclosure is a driving and measuring circuit for controlling an impedance measuring device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measuring device comprising: a storage element that stores or releases electric energy; a switching circuit that includes a plurality of switching elements and that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, and the driving and measuring circuit controls the impedance measuring device to measure the AC impedance of a first battery and a second battery connected in series, based on the detection result of the current detection means. The power supply comprises a current measuring unit that measures the current of a first battery and the current of the second battery, a voltage measuring unit that measures the voltage of the first battery and the voltage of the second battery, an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from a higher-level system having a function of calculating AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement results of the voltage measuring unit and the measurement results of the current measuring unit, and outputs the measured values ​​to the higher-level system, and a drive control unit that drives the plurality of switching elements so as to periodically change the state of movement of electrical energy through the storage elements according to the measurement frequency.

[0008] An impedance measuring device according to one aspect of the present disclosure is an impedance measuring device that measures the AC impedance of a first battery and a second battery connected in series, and includes: a storage element that stores or releases electrical energy; a switching circuit consisting of a plurality of switching elements that intermittently transfers electrical energy between the first battery and the second battery via the storage element; current detection means that detects the current of the first battery and the current of the second battery; and a drive measurement circuit, wherein the drive measurement circuit includes: a current measurement unit that measures the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement unit that measures the voltage of the first battery and the voltage of the second battery; an AC detection unit that receives a measurement instruction signal including information about a measurement frequency from a higher-level system having a function of calculating AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit and outputs the results to the higher-level system; and a drive control unit that drives the plurality of switching elements to periodically change the state of transfer of electrical energy via the storage element in accordance with the measurement frequency.

[0009] An impedance measurement system according to one aspect of the present disclosure includes an impedance measurement device that measures the AC impedance of a first battery and a second battery connected in series, a drive measurement circuit for controlling the impedance measurement device, and a host system having a function of calculating the AC impedance, wherein the impedance measurement device includes a storage element that stores or releases electrical energy, a switching circuit that includes a plurality of switching elements and intermittently transfers electrical energy between the first battery and the second battery via the storage elements, current detection means that detects the current of the first battery and the current of the second battery, and the drive measurement circuit comprises: a current measurement unit that measures the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement unit that measures the voltage of the first battery and the voltage of the second battery; an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from the higher-level system, and measures an AC voltage and an AC current according to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit, and outputs the measured values ​​to the higher-level system; and a drive control unit that drives the plurality of switching elements so as to periodically change the state of movement of electrical energy via the storage elements according to the measurement frequency.

[0010] A driving and measuring method according to one aspect of the present disclosure is a driving and measuring method for controlling an impedance measuring device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measuring device comprising: a storage element that stores or releases electric energy; a switching circuit that includes a plurality of switching elements and that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detecting means that detects the current of the first battery and the current of the second battery, and the driving and measuring method includes receiving a measurement frequency from a host system having a function of calculating the AC impedance. a driving step of driving the plurality of switching elements so as to periodically change the state of movement of electrical energy through the storage elements in accordance with the measurement frequency; a current measuring step of measuring the current of the first battery and the current of the second battery based on the detection result of the current detecting means; a voltage measuring step of measuring the voltage of the first battery and the voltage of the second battery; and an AC detecting step of measuring an AC voltage and an AC current corresponding to the measurement frequency based on the measurement result in the voltage measuring step and the measurement result in the current measuring step, and outputting the measured values ​​to the upper system.

[0011] According to a driving and measuring circuit according to an aspect of the present disclosure, it is possible to reduce the size of an impedance measuring device.

[0012] FIG. 1 is a schematic diagram showing an example of an impedance measurement system according to a first embodiment. FIG. 2 is a circuit diagram showing an example of a voltage measurement unit, a current measurement unit, and an AC detection unit of an impedance measurement device according to the first embodiment. FIG. 3 is a circuit diagram showing an example of a drive control unit of an impedance measurement device according to the first embodiment. FIG. 4 is a timing chart showing an example of the operation of an impedance measurement device according to the first embodiment. FIG. 5 is a schematic diagram showing an example of an impedance measurement device according to a second embodiment. FIG. 6 is a diagram showing an example of a current measurement unit of an impedance measurement device according to the second embodiment. FIG. 7 is a schematic diagram showing an example of an impedance measurement device according to a third embodiment. FIG. 8 is a circuit diagram showing an example of a drive control unit of an impedance measurement device according to the third embodiment. FIG. 9 is a timing chart showing an example of the operation of an impedance measurement device according to the third embodiment. FIG. 10 is a circuit diagram showing an example of a drive control unit of an impedance measurement device according to a fourth embodiment. FIG. 11 is a timing chart showing an example of the operation of an impedance measurement device according to the fourth embodiment. FIG. 12 is a flowchart showing an example of a drive measurement method according to another embodiment.

[0013] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0014] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0015] (Embodiment 1) Fig. 1 is a schematic diagram showing an example of an impedance measurement system 100 according to embodiment 1. In Fig. 1, batteries B1 and B2 are also shown in addition to the impedance measurement system 100.

[0016] The impedance measurement system 100 includes an impedance measurement device 1 and a host system 200. The impedance measurement device 1 is a device that measures the AC impedance of batteries B1 and B2 connected in series. Battery B1 is an example of a first battery, and battery B2 is an example of a second battery. For example, batteries B1 and B2 are rechargeable secondary batteries such as lithium-ion batteries, and battery B1 is arranged on a higher potential side than battery B2. The host system 200 is a system that has the function of calculating the AC impedance.

[0017] The impedance measuring device 1 includes a storage element that stores or releases electrical energy, a switching circuit consisting of a plurality of switching elements that intermittently transfers electrical energy between batteries B1 and B2 via the storage elements, current detection means that detects the current of battery B1 and the current of battery B2, and a driving and measuring circuit 2. Note that the impedance measuring device 1 does not necessarily have to include the driving and measuring circuit 2, and the impedance measuring device 1 and the driving and measuring circuit 2 may be provided separately. Similarly, in the second to fourth embodiments described below, the impedance measuring device and the driving and measuring circuit may be provided separately.

[0018] In the first embodiment, the energy storage element is an inductor 14. In the first embodiment, the switching circuit includes a first switching element 11 that forms a first loop together with battery B1 and inductor 14, and a second switching element 12 that forms a second loop together with battery B2 and inductor 14. For example, the switching circuit includes current interruption means 13 connected in series with inductor 14. For example, the current detection means includes a detection resistor 15 connected between battery B1 and the first switching element 11, and a detection resistor 16 connected between battery B2 and the second switching element 12. The detection resistor 15 is an example of a first detection resistor, and the detection resistor 16 is an example of a second detection resistor. The current of battery B1 can be detected by detecting the current flowing through detection resistor 15, and the current of battery B2 can be detected by detecting the current flowing through detection resistor 16.

[0019] The first switching element 11 and the second switching element 12 are, for example, N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The drain of the first switching element 11 is connected to the positive electrode of battery B1, the source of the first switching element 11 is connected to the drain of the second switching element 12, and the source of the second switching element 12 is connected to the negative electrode of battery B2. A series circuit of current interruption means 13 and inductor 14 is connected between the junction of batteries B1 and B2 and the junction of the first switching element 11 and second switching element 12. For example, a detection resistor 15 is connected between the positive electrode of battery B1 and the drain of the first switching element 11 to detect the charging / discharging current I1 of battery B1. For example, the detection resistor 16 is connected between the negative electrode of the battery B2 and the source of the second switching element 12 to detect the charge / discharge current I2 of the battery B2.

[0020] The first switching element 11 and the second switching element 12 are switching elements that are turned on by applying a voltage to their control terminals (gates) and that conduct current in the opposite direction (the direction opposite to the arrows of currents I1 and I2 shown in Figure 1) by means of, for example, body diodes, and are represented as field-effect transistors as an example. Furthermore, the current interruption means 13 conducts and interrupts current in both directions, so is usually configured with two field-effect transistors connected face to face, but to avoid complicating the diagram, it is represented by the circuit symbol for a switch.

[0021] The drive measurement circuit 2 is a circuit for controlling the impedance measurement device 1 (specifically, the switching circuit provided in the impedance measurement device 1), and includes a voltage measurement unit 20, a current measurement unit 21, an AC detection unit 22, and a drive control unit 23.

[0022] The voltage measurement unit 20 measures the voltage of battery B1 and the voltage of battery B2. The current measurement unit 21 measures the current of battery B1 and the current of battery B2 based on the detection result of the current detection means. Specifically, the current measurement unit 21 measures the current I1 flowing from the detected voltage Vc1 of the detection resistor 15 to battery B1, and measures the current I2 flowing from the detected voltage Vc2 of the detection resistor 16 to battery B2.

[0023] The AC detection unit 22 receives a measurement instruction signal including information on the measurement frequency from the host system 200, and transmits an enable signal EN and a control signal Vs to the drive control unit 23 in accordance with the measurement instruction signal, and also transmits information necessary for calculating the AC impedance (voltage information from the voltage measurement unit 20 and current information from the current measurement unit 21) to the host system 200. Details of the AC detection unit 22 will be described later.

[0024] The drive control unit 23 drives the first switching element 11 and the second switching element 12 based on the enable signal EN and the control signal Vs from the AC detection unit 22. The drive control unit 23 will be described in detail later.

[0025] The upper system 200 may be any system having a calculation function such as a CPU, such as an MCU (Micro Control Unit) or an ECU (Electronic Control Unit).

[0026] Next, the configuration of the AC detection unit 22 will be described in detail.

[0027] FIG. 2 is a circuit diagram showing an example of the voltage measurement unit 20, current measurement unit 21, and AC detection unit 22 of the impedance measurement device 1 according to the first embodiment. FIG. 2 mainly shows the internal configurations of the voltage measurement unit 20, current measurement unit 21, and AC detection unit 22. In FIG. 2, battery B1 and battery B2 each consist of a plurality of battery cells connected in series, and the voltage measurement unit 20 is configured to measure the voltage of each battery cell. Both the voltage measurement unit 20 and the current measurement unit 21 have analog-to-digital converters (hereinafter abbreviated as ADCs) that convert the detected voltages into digital signals, and the voltage information from the voltage measurement unit 20 and the current information from the current measurement unit 21 are transmitted to the AC detection unit 22 as digital values. Each ADC measures the voltage and current of batteries B1 and B2 at the sampling frequency of a clock signal CK, which will be described later.

[0028] As shown in FIG. 2, for example, the AC detection unit 22 includes a signal generation unit 220 , a conversion unit 221 , an integration unit 222 , a holding unit 223 , and a communication unit 224 .

[0029] The signal generating unit 220 outputs a first reference frequency signal of frequency f in accordance with a measurement command from the upper system 200, a second reference frequency signal having a phase orthogonal to that of the first reference frequency signal, and a clock signal CK to each ADC of the voltage measuring unit 20 and the current measuring unit 21. The first reference frequency signal is a sine wave (sin), and the second reference frequency signal is a cosine wave (cos). The clock signal CK is a signal with a higher frequency than the first reference frequency signal and is synchronized with the first reference frequency signal.

[0030] The conversion unit 221 has a multiplier pair corresponding to each ADC, and converts each digital value from each ADC into a real part component and an imaginary part component of a complex voltage and a complex current by multiplying each digital value from each ADC by a first reference frequency signal sin and a second reference frequency signal cos using each multiplier pair. The multiplication result by the first reference frequency signal sin indicates the real part component when the sampled voltage is expressed as a complex voltage. The multiplication result by the second reference frequency signal cos indicates the imaginary part component when the sampled voltage is expressed as a complex voltage.

[0031] The integrator 222 includes averaging circuit pairs corresponding to the multiplier pairs of the converter 221, and averages the real and imaginary components of the complex voltage and complex current repeatedly measured and converted by the converter 221. This averaging reduces measurement errors in the complex voltage and complex current, and oversampling improves resolution (measurement accuracy). This makes it possible to obtain AC impedance measurement results with 20- to 24-bit accuracy even with an ADC with a small number of bits (for example, about 16 bits).

[0032] The holding unit 223 holds the real and imaginary components of the complex voltage and complex current after averaging. Each register pair for holding the complex voltage consists of a register Re that holds the real component of the complex voltage and complex current of the corresponding battery cell, and a register Im that holds the imaginary component.

[0033] The communication unit 224 is a communication circuit for communicating with the host system 200, and is used to transmit data stored in the holding unit 223 to the host system 200, and to receive measurement instruction signals (operation instructions to the drive control unit 23 and information on the frequency f of the first reference frequency signal) from the host system 200. The communication performed by the communication unit 224 may be wireless communication or wired communication, and there are no particular limitations on the communication standard.

[0034] Next, the configuration of the drive control unit 23 will be described in detail.

[0035] 3 is a circuit diagram showing an example of the drive control unit 23 of the impedance measuring device 1 according to embodiment 1. FIG. 3 shows the internal configuration of the drive control unit 23.

[0036] 3, oscillator 230 outputs a reference clock CK0 that sets the switching period, and a clock CK1 that is delayed from reference clock CK0 by the maximum on-period of first switching element 11 and second switching element 12. In the first embodiment, an example is shown in which these clock signals are generated by oscillator 230 of drive control unit 23, but these clock signals may be received from higher-level system 200 or the like, or clock signal CK of AC detection unit 22 may be used, or these clock signals may be signals synchronized with clock signal CK.

[0037] The reference voltage source 231 generates a threshold voltage Vr1, the reference voltage source 232 generates a threshold voltage Vr2, the comparator 233 compares the detection voltage Vc1 with the threshold voltage Vr1, and the comparator 234 compares the detection voltage Vc2 with the reference voltage Vr2. In the present disclosure, an example is shown in which these threshold voltages are generated inside the drive control unit 23, but these threshold voltages may be supplied from the higher-level system 200 or the like, or may be made variable in response to an instruction from the higher-level system 200, as will be described later.

[0038] The clock CK1 and the output of the comparator 233 and the output of the comparator 234 are input to the OR circuit 235. The reference clock CK0 sets the SR latch 236, and the output of the OR circuit 235 resets the SR latch 236. The outputs Q and NQ of the SR latch 236 are input to the switch circuits 237 and 238. The control signal Vs from the AC detection unit 22 is a signal that switches between high and low depending on the phase of the first reference frequency signal. Since the first reference frequency signal is a signal of the measurement frequency (frequency f) in accordance with the measurement command from the upper system 200, the control signal Vs is a signal of frequency f. When the control signal Vs is at an H level, the switch circuit 237 selects and outputs the output Q of the SR latch 236, and the switch circuit 238 selects and outputs the output NQ. When the control signal Vs is at an L level, the switch circuit 237 selects and outputs the output NQ of the SR latch 236, and the switch circuit 238 selects and outputs the output Q. The output of the switch circuit 237 becomes a signal that drives the first switching element 11 , and the output of the switch circuit 238 becomes a signal that drives the second switching element 12 .

[0039] The abnormality detection circuit 239 is not essential to the present application and will not be described or illustrated in detail. However, the abnormality detection circuit 239 outputs an H-level abnormality signal Fail when the current or voltage value of each battery detected by the AC detection unit 22 or the temperature of each battery detected by a temperature sensor (not shown) indicates an abnormal value. The abnormality signal Fail is logically inverted by an inverter 240 and input to an AND circuit 241 together with an enable signal EN. The output of the AND circuit 241 is a drive signal V13 for the current interruption means 13. When the drive signal V13 is H-level, the current interruption means 13 is conductive, and when it is L-level, it is interrupted. The output of the switch circuit 237 and the drive signal V13 are input to an AND circuit 242, which outputs a drive signal Vg1. The output of the switch circuit 238 and the drive signal V13 are input to an AND circuit 243, which outputs a drive signal Vg2. In other words, if there is no abnormality and a measurement instruction is received from the upper system 200, the drive signal V13 causes the current interruption means 13 to conduct, electrically connecting the inductor 14 to the first switching element 11 and the second switching element 12, and the first switching element 11 and the second switching element 12 are alternately driven on and off.

[0040] A dead time is provided during which the normal drive signal Vg1 and the drive signal Vg2 are simultaneously turned off so that the first switching element 11 and the second switching element 12 are not simultaneously turned on. Although not shown, it is assumed here that a delay time equivalent to the dead time is provided at the rising edge of each drive signal.

[0041] Next, the operation of the drive control unit 23 will be described in detail.

[0042] FIG. 4 is a timing chart showing an example of the operation of the impedance measuring device 1 according to the first embodiment. FIG. 4 is a timing chart showing the operation of the main components of the drive control unit 23, and illustrates the reference clock CK0, clock CK1, control signal Vs, drive signal Vg1, detection voltage Vc1, drive signal Vg2, and detection voltage Vc2. Although not shown, the enable signal EN is at an H level, and the abnormality signal Fail is at an L level. The detection voltage Vc1 corresponds to the current I1 flowing through the battery B1 and the first switching element 11, and the detection voltage Vc2 corresponds to the current I2 flowing through the battery B2 and the second switching element 12. For example, the threshold voltages Vr1 and Vr2 may be the same voltage; in FIG. 4, the threshold voltages Vr1 and Vr2 are indicated as threshold voltage Vr. Hereinafter, using FIG. 4, we will explain how the drive control unit 23 of the impedance measuring device 1 according to the first embodiment efficiently passes high-frequency current pulses through the batteries B1 and B2.

[0043] First, we will explain the operation of drive control unit 23 from time t0 to t2 when control signal Vs is at H level, as shown on the left side of Fig. 4. Since control signal Vs is at H level from time t0 to t2, output Q of SR latch 236 is output as drive signal Vg1 for first switching element 11, and output NQ of SR latch 236 is output as drive signal Vg2 for second switching element 12.

[0044] At time t0, when the reference clock CK0 rises, the SR latch 236 is set, output Q, i.e., drive signal Vg1, rises, and output NQ, i.e., drive signal Vg2, falls. Drive signal Vg1 turns on the first switching element 11, causing current I1 to flow through the first loop from the positive electrode of battery B1 to the negative electrode of battery B1 via the first switching element 11, inductor 14, and current interruption means 13. Meanwhile, drive signal Vg2 goes low, turning off the second switching element 12, preventing current I2 from flowing and reducing the detection voltage Vc2 to zero. Current I1 increases at a rate determined by the voltage of battery B1 and the inductance of inductor 14, and detection voltage Vc1 also increases in proportion to current I1.

[0045] At time t1, when the detection voltage Vc1 reaches the threshold voltage Vr1, the output of the comparator 233 inverts to a high level, resetting the SR latch 236 via the OR circuit 235. The reset of the SR latch 236 causes the output Q, i.e., the drive signal Vg1, to fall, and the output NQ, i.e., the drive signal Vg2, to rise. The first switching element 11 turns off, and the voltage of the inductor 14 inverts. The body diode of the second switching element 12 conducts, and after a dead time, the second switching element 12 turns on. Note that the dead time is very short and is not shown in the figure; instead, the conduction of the body diode of the second switching element 12 and the turn-on of the second switching element 12 are depicted as occurring simultaneously at time t1. The current in the inductor 14 is maintained, and current I2 flows through a second loop from the negative terminal of battery B2 to the positive terminal of battery B2 via the second switching element 12, inductor 14, and current interruption means 13. This is a negative current in the opposite direction to the current I2 in the figure, and increases in the positive direction at a gradient determined by the voltage of battery B2 and the inductance of inductor 14, with the current value whose absolute value corresponds to the threshold voltage Vr1 as the initial value.

[0046] At time t2, the reference clock CK0 rises, and the operation from time t0 is repeated. This repetition causes a pulse current I1 to flow in a direction discharging battery B1, with a peak current value corresponding to threshold voltage Vr1, and a pulse current I2 to flow in a direction charging battery B2, with a peak current value corresponding to threshold voltage Vr1.

[0047] Next, at time t3, when the control signal Vs goes low, the switch circuit 237 switches to select and output the output NQ of the SR latch 236, and the switch circuit 238 switches to select and output the output Q of the SR latch 236. Therefore, the timing at which the drive signals Vg1 and Vg2 rise also changes. Specifically, the drive signal Vg2 goes high at the rising edge of the reference clock CK0, and goes low when the detection voltage Vc2 reaches the threshold voltage Vr2 or when the clock CK1 rises. From time t3, the current I2 continues to flow, and the current I2 increases.

[0048] At time t4, when the on state of the second switching element 12 reaches the maximum on period, clock CK1 rises, the SR latch 236 is reset via the OR circuit 235, the drive signal Vg2 falls, and the second switching element 12 is turned off. If the increasing current I2 has now reached a positive direction, the voltage of the inductor 14 reverses. The body diode of the first switching element 11 becomes conductive, and after a dead time, the first switching element 11 turns on.

[0049] At time t5, the reference clock CK0 rises, the SR latch 236 is set, output Q (i.e., drive signal Vg2) rises, and output NQ (i.e., drive signal Vg1) falls. Drive signal Vg2 turns on the second switching element 12, causing current I2 to flow through the second loop from the positive electrode of battery B2 to the negative electrode of battery B2 via the current interruption means 13, inductor 14, and second switching element 12. Meanwhile, drive signal Vg1 goes low, turning off the first switching element 11. Current I1 does not flow, and detection voltage Vc1 also drops to zero. Current I2 increases at a rate determined by the voltage of battery B2 and the inductance of inductor 14, and detection voltage Vc2 also increases in proportion to current I2. Thereafter, the operation from time t3, when the second switching element 12 performs switching operation for the maximum on-period, is repeated. This repetition causes the peak value of current I2 to increase.

[0050] At time t6, when the detected voltage Vc2 of current I2 reaches the threshold voltage Vr2, the output of comparator 234 inverts to the H level and resets SR latch 236 via OR circuit 235. Resetting SR latch 236 causes output Q, i.e., drive signal Vg2, to fall, and output NQ, i.e., drive signal Vg1, to rise. Second switching element 12 turns off, and the voltage of inductor 14 inverts. The body diode of first switching element 11 conducts, and after a dead time, first switching element 11 turns on. Current in inductor 14 is maintained, and current I1 flows through the first loop from the negative electrode of battery B1 through current interruption means 13, inductor 14, and first switching element 11 to the positive electrode of battery B1. This is a negative current in the opposite direction to the current I1 in the figure, and increases in the positive direction at a gradient determined by the voltage of battery B1 and the inductance of inductor 14, with the current value whose absolute value corresponds to the threshold voltage Vr2 as the initial value.

[0051] At time t7, the reference clock CK0 rises, and the operation from time t5 is repeated. This repetition causes a pulse current I2 to flow in a direction discharging battery B2, with a peak current value corresponding to threshold voltage Vr2, and a pulse current I1 to flow in a direction charging battery B1, with a peak current value corresponding to threshold voltage Vr2.

[0052] Next, at time t8, when the control signal Vs goes high, the switch circuit 237 switches to select and output the output Q of the SR latch 236, and the switch circuit 238 switches to select and output the output NQ of the SR latch 236. Therefore, the timing at which the drive signals Vg1 and Vg2 rise also changes. Specifically, the drive signal Vg1 goes high at the rising edge of the reference clock CK0, and goes low when the detection voltage Vc2 reaches the threshold voltage Vr2 or when the clock CK1 rises. From time t8, the current I1 continues to flow, and the current I1 increases.

[0053] After this, due to the switching operation of the first switching element 11 during the maximum on period, the current I1 increases and the current I2 decreases, and eventually the peak value of the current I1 becomes a current value corresponding to the threshold voltage Vr1, and the operation from time t0 onwards is carried out again.

[0054] As described above, in accordance with the control signal Vs, battery B1 and battery B2 are repeatedly charged and discharged with a pulse current of a predetermined peak value with low loss. Current I1, which is the charging / discharging current, is converted to detection voltage Vc1 by detection resistor 15, and current I2 is converted to detection voltage Vc2 by detection resistor 16, and these are input to current measurement unit 21. During measurement of AC impedance, impedance measurement device 1 regenerates energy drawn from battery B1 to battery B2 during the H level period of control signal Vs, and regenerates energy drawn from battery B2 to battery B1 during the L level period of control signal Vs. Therefore, if the H level period and the L level period of control signal Vs are equal and threshold voltage Vr1 and threshold voltage Vr2 are equal, the charging and discharging charges of battery B1 and battery B2 will also be equal, thereby suppressing fluctuations in battery voltage and changes in charge capacity SOC (state of charge).

[0055] Conversely, energy can be transferred from battery B1 to battery B2, or from battery B2 to battery B1, by making threshold voltage Vr1 and threshold voltage Vr2 different from each other or by changing the ratio of the high and low periods of the control signal Vs. For example, when transferring energy from battery B1 to battery B2, it is advisable to set threshold voltage Vr1 higher than threshold voltage Vr2, or to make the H level period of the control signal Vs longer than the L level period. Although it is different from the gist of the present disclosure, this energy transfer can also be applied to maintaining battery voltage balance because the voltage of each battery is also monitored.

[0056] As described above, AC detection unit 22 receives a measurement instruction signal including information about the measurement frequency from host system 200, which has a function of calculating AC impedance, and measures AC voltage and AC current according to the measurement frequency based on the measurement results of voltage measurement unit 20 and current measurement unit 21, and outputs the measured values ​​to host system 200. Furthermore, drive control unit 23 drives a plurality of switching elements (here, first switching element 11 and second switching element 12) so as to periodically change the state of transfer of electrical energy via inductor 14 according to the measurement frequency.

[0057] This periodically changes the state of electrical energy transfer between batteries B1 and B2 in accordance with the measurement frequency, allowing the AC voltage and AC current to be measured in accordance with the measurement frequency, thereby enabling the AC impedance of batteries B1 and B2 to be measured. The state of electrical energy transfer can be changed via a single inductor 14 provided in the impedance measuring device 1, eliminating the need for both an inductor and a power storage device (capacitor) as in the method disclosed in Patent Document 2. This allows the impedance measuring device 1 to be miniaturized. In other words, the AC impedance of batteries B1 and B2 connected in series can be appropriately obtained with a small number of components.

[0058] In the method disclosed in Patent Document 2, the power storage device may be a battery, but is restricted to a lower potential than the battery of the object being measured. On the other hand, the driving measurement circuit 2 can measure AC impedance without being affected by the magnitude relationship between the voltages of batteries B1 and B2, so usage restrictions can be relaxed.

[0059] Furthermore, the method disclosed in Patent Document 2 has the problem that, in order to prevent a decrease in the battery's SOC (State of Charge), time is required for the energy charged in the power storage device during measurement to be regenerated back into the battery after the measurement. On the other hand, the driving and measuring circuit 2 generates an intermittent current at all times without any pauses during measurement, thereby shortening the measurement time.

[0060] 2, batteries B1 and B2 may each be composed of two or more battery cells, and voltage measurement unit 20 may simultaneously measure the voltages of the two or more battery cells, thereby enabling the voltages of battery B1 and battery B2 to be measured in a short time.

[0061] 4, the drive control unit 23 may alternately turn on the first switching element 11 and the second switching element 12 at a frequency higher than the measurement frequency. This shortens the time during which a current flows through the inductor 14 at one time. In other words, since a large current is less likely to flow through the inductor 14, the inductor 14 can be made smaller, which in turn enables the impedance measuring device 1 to be made smaller.

[0062] In addition, the drive control unit 23 may control the on-time of the first switching element 11 and the on-time of the second switching element 12 so as to repeat, at a period corresponding to the measurement frequency, a first energy transfer state (from time t0 to time t4 in Figure 4) in which a discharge current is caused to flow from battery B1 when the first switching element 11 is on and a charge current is caused to flow to battery B2 when the second switching element 12 is on, and a second energy transfer state (from time t4 to time t8 in Figure 4) in which a discharge current is caused to flow from battery B2 when the second switching element 12 is on and a charge current is caused to flow to battery B1 when the first switching element 11 is on.

[0063] As a result, by lengthening the on-time of the second switching element 12, a discharge current can be started to flow from battery B2, as shown from time t3 to time t4 in Fig. 4, and as a result, the state can be switched from the first energy transfer state to the second energy transfer state. Also, by lengthening the on-time of the first switching element 11, a discharge current can be started to flow from battery B1, as shown from time t8 onwards in Fig. 4, and as a result, the state can be switched from the second energy transfer state to the first energy transfer state.

[0064] Furthermore, the drive control unit 23 may limit the peak value of the discharge current from battery B1 to a predetermined value (a value corresponding to threshold voltage Vr1) in the first energy transfer state, and may limit the peak value of the discharge current from battery B2 to a predetermined value (a value corresponding to threshold voltage Vr2) in the second energy transfer state. This makes it possible to limit the discharge current from battery B1 and the discharge current from battery B2, thereby suppressing switching loss that occurs during switching.

[0065] The switching circuit may also have current interruption means 13 connected in series with inductor 14, and drive control unit 23 may interrupt the current flowing through current interruption means 13 when the detection results of detection resistors 15 and 16 exceed a predetermined amount. This makes it possible to interrupt the current when an overcurrent flows.

[0066] (Embodiment 2) Next, a description will be given of embodiment 2. In embodiment 2, the current detection means has one of detection resistors 15 connected between battery B1 and first switching element 11 and detection resistor 16 connected between battery B2 and second switching element 12, and detection resistor 17 connected in series with inductor 14. An example in which the current detection means has detection resistors 16 and 17 will be described below.

[0067] FIG. 5 is a schematic diagram showing an example of an impedance measuring device 1A according to a second embodiment. In addition to the impedance measuring device 1A, FIG. 5 also shows batteries B1 and B2. In FIG. 5, components similar to those shown in FIG. 1 are given the same reference numerals, and their description will be omitted or simplified. The difference from the impedance measuring device 1 shown in FIG. 1 is the configuration for detecting the current of battery B1. Instead of the detection resistor 15 in FIG. 1, a detection resistor 17 is inserted in series with the current interruption means 13 and the inductor 14, and a current I3 flowing through the detection resistor 17 is detected. The voltage across the detection resistor 17 is defined as a detection voltage Vc3, which is input to a current measuring unit 21A for processing.

[0068] FIG. 6 is a configuration diagram showing an example of a current measurement unit 21A of an impedance measurement device 1A according to embodiment 2. In addition to the current measurement unit 21A, FIG. 6 also shows peripheral circuits of the current measurement unit 21A. Compared to the current measurement unit 21 of FIG. 2, the current measurement unit 21A includes an adder 210, which outputs the sum of the outputs of an ADC that digitally converts the detection voltage Vc2 and an ADC that digitally converts the detection voltage Vc3 as detection data for the current I1. Since the current I3 flowing through the detection resistor 17 is the difference between the currents I1 and I2 (i.e., I3 = I1 - I2), to detect the current I1 in the same manner as in embodiment 1 of FIG. 1, it is sufficient to calculate the sum of the currents I2 and I3 (i.e., I1 = I2 + I3).

[0069] As described above, in the second embodiment, the position of the detection resistor is changed from that of the first embodiment, and the signal processing is also changed accordingly. Compared to the first embodiment, in which the detection resistor 15 is connected to a high potential such as the positive electrode of battery B1, the detection resistor 15 is connected to the midpoint of the battery, which simplifies the configuration of the level shift circuit and improves detection accuracy. Although not shown, the detection resistor 15 may be provided instead of the detection resistor 16. In other words, the detection resistor 15 may be connected to a high potential such as the positive electrode of battery B1.

[0070] It should be noted that part or all of the drive and measurement circuit 2 of the first embodiment, or part or all of the drive and measurement circuit 2A of the second embodiment, may be integrated into an integrated circuit, thereby enabling further miniaturization and versatility of the device.

[0071] Third Embodiment In the first and second embodiments, an example in which the storage element that stores or releases electrical energy is the inductor 14 is described. In a third embodiment, an example in which the storage element is a capacitor will be described.

[0072] Fig. 7 is a schematic diagram showing an example of an impedance measuring device 3 according to embodiment 3. Fig. 7 also shows batteries B1 and B2 in addition to the impedance measuring device 3. The impedance measuring device 3 measures the AC impedance of batteries B1 and B2 connected in series.

[0073] The impedance measuring device 3 comprises a storage element that stores or releases electrical energy, a switching circuit consisting of a plurality of switching elements that intermittently transfers electrical energy between battery B1 and battery B2 via the storage element, current detection means that detects the current of battery B1 and the current of battery B2, and drive measurement circuits 4 and 5.

[0074] In the third embodiment, the energy storage element is a capacitor 30. In the third embodiment, the switching circuit has a third switching element 31 connected between the positive electrode of battery B1 and the positive electrode of capacitor 30, and a fourth switching element 32 connected between the negative electrode of battery B1 and the positive electrode of capacitor 30. The switching circuit also has a fifth switching element 34 connected between the negative electrode of battery B2 and the negative electrode of capacitor 30, and a sixth switching element 35 connected between the positive electrode of battery B2 and the negative electrode of capacitor 30.

[0075] For example, the current detection means includes a detection resistor 33 connected between battery B1 and the third switching element 31, and a detection resistor 36 connected between battery B2 and the fifth switching element 34. The detection resistor 33 is an example of a first detection resistor, and the detection resistor 36 is an example of a second detection resistor. The current of battery B1 can be detected by detecting the current flowing through the detection resistor 33, and the current of battery B2 can be detected by detecting the current flowing through the detection resistor 36. The current I1 flowing through battery B1 is converted to a detection voltage Vc1 by the detection resistor 33, and the current I2 flowing through battery B2 is converted to a detection voltage Vc2 by the detection resistor 36.

[0076] The third switching element 31, the fourth switching element 32, the fifth switching element 34, and the sixth switching element 35 are, for example, N-channel MOSFETs. The drain of the third switching element 31 is connected to the positive electrode of battery B1, and the source of the third switching element 31 is connected to the positive electrode of capacitor 30. The drain of the fourth switching element 32 is connected to the positive electrode of capacitor 30, and the source of the fourth switching element 32 is connected to the negative electrode of battery B1. The drain of the fifth switching element 34 is connected to the negative electrode of capacitor 30, and the source of the fifth switching element 34 is connected to the negative electrode of battery B2. The drain of the sixth switching element 35 is connected to the positive electrode of battery B2, and the source of the sixth switching element 35 is connected to the negative electrode of capacitor 30.

[0077] In response to a measurement instruction signal from the host system 200, the drive measurement circuit 4 outputs a drive signal Vg3 for the third switching element 31 and a drive signal Vg4 for the fourth switching element 32, receives the voltage and current detection signal Vc1 of battery B1, and transmits the measurement results to the host system 200. Similarly, in response to a measurement instruction signal from the host system 200, the drive measurement circuit 5 outputs a drive signal Vg5 for the fifth switching element 34 and a drive signal Vg6 for the sixth switching element 35, receives the voltage and current detection signal Vc2 of battery B2, and transmits the measurement results to the host system 200.

[0078] The third switching element 31, the fourth switching element 32, the fifth switching element 34, and the sixth switching element 35 are switching elements that are turned on by application of a voltage to their control terminals (gates) and that conduct current in the reverse direction (the direction opposite to the arrows of currents I1 and I2 shown in FIG. 7) by means of, for example, a body diode, and are represented as field-effect transistors as an example.

[0079] The drive measurement circuit 4 includes a voltage measurement section 40, a current measurement section 41, an AC detection section 42, and a drive control section 43. The drive measurement circuit 5 includes a voltage measurement section 50, a current measurement section 51, an AC detection section 52, and a drive control section 53.

[0080] The voltage measurement unit 40 measures the voltage of the battery B1. The current measurement unit 41 measures the current of the battery B1 based on the detection result of the current detection means. Specifically, the current measurement unit 41 measures the current I1 flowing from the detected voltage Vc1 of the detection resistor 33 to the battery B1.

[0081] The AC detection unit 42 receives a measurement instruction signal including information on the measurement frequency from the upper system 200, and transmits an enable signal EN and a control signal Vs to the drive control unit 43 in accordance with the measurement instruction signal, and also transmits information necessary for calculating the AC impedance of battery B1 (voltage information from the voltage measurement unit 40 and current information from the current measurement unit 41) to the upper system 200.

[0082] The drive control unit 43 drives the third switching element 31 and the fourth switching element 32 based on the enable signal EN and the control signal Vs from the AC detection unit 42. The drive control unit 43 will be described in detail later.

[0083] The voltage measurement unit 50 measures the voltage of battery B2. The current measurement unit 51 measures the current of battery B2 based on the detection result of the current detection means. Specifically, the current measurement unit 51 measures the current I2 flowing from the detected voltage Vc2 of the detection resistor 36 to battery B2.

[0084] The AC detection unit 52 receives a measurement instruction signal including information on the measurement frequency from the upper system 200, and in accordance with the measurement instruction signal, transmits an enable signal EN and a control signal Vs to the drive control unit 53, and also transmits information necessary for calculating the AC impedance of battery B2 (voltage information from the voltage measurement unit 50 and current information from the current measurement unit 51) to the upper system 200.

[0085] The drive control unit 53 drives the fifth switching element 34 and the sixth switching element 35 based on the enable signal EN and the control signal Vs from the AC detection unit 52. The drive control unit 53 will be described in detail later.

[0086] The drive measurement circuit 4 and the drive measurement circuit 5 also share and transmit clock signals and abnormality signals, which will be described later, via a communication unit 6 .

[0087] The voltage measurement unit 40 of the drive measurement circuit 4 and the voltage measurement unit 50 of the drive measurement circuit 5 have the same configuration as the voltage measurement unit 20 shown in Figure 2, the current measurement unit 41 of the drive measurement circuit 4 and the current measurement unit 51 of the drive measurement circuit 5 have the same configuration as the current measurement unit 21 shown in Figure 2, and the AC detection unit 42 of the drive measurement circuit 4 and the AC detection unit 52 of the drive measurement circuit 5 have the same configuration as the AC detection unit 22 shown in Figure 2, so illustrations and detailed explanations will be omitted.

[0088] Fig. 8 is a circuit diagram showing an example of the drive control units 43 and 53 of the impedance measuring device 3 according to embodiment 3. Part of the communication unit 6 is also shown in Fig. 8. Fig. 8 shows the internal configuration of the drive control unit 43 of the drive measurement circuit 4, the drive control unit 53 of the drive measurement circuit 5, and part of the communication unit 6.

[0089] 8, the oscillator 430 outputs a reference clock CK0 with a duty ratio of 50% that sets the switching period. In the third embodiment, an example is shown in which the reference clock CK0 is generated by the oscillator 430 of the drive control unit 43, but the reference clock CK0 may be received from the higher-level system 200 or the drive measurement circuit 5, or the clock signal CK of the AC detection unit 42 or the AC detection unit 52 may be used, or the reference clock CK0 may be a signal synchronized with the clock signal CK.

[0090] The frequency divider circuit 431, which is configured with a D latch, divides the frequency of the control signal Vs from the host system 200 by two and outputs a frequency-divided signal Vs1. In Fig. 8, the frequency divider circuit 431 is shown as being provided in the drive control unit 43 (drive measurement circuit 4), but it may also be provided in the host system 200 or the drive measurement circuit 5.

[0091] The reference clock CK0, the control signal Vs, and the frequency-divided signal Vs1 are input to an AND circuit 432. An inverted signal of the frequency-divided signal Vs1 obtained via an inverter 433 and the output of the AND circuit 432 are input to an OR circuit 434. The output of the OR circuit 434 becomes a signal that drives the third switching element 31, and an inverted signal obtained from the output of the OR circuit 434 via an inverter 435 becomes a signal that drives the fourth switching element 32.

[0092] The abnormality detection circuit 436 is not essential to the present application and will not be described or illustrated in detail, but the abnormality detection circuit 436 outputs an H-level abnormality signal Fail1 when the current value or voltage value of battery B1 detected by AC detection unit 42, or the temperature of battery B1 detected by a temperature sensor (not shown), indicates an abnormal value. The abnormality signal Fail1 is input to an AND circuit 438 via a NOR circuit 437 together with an enable signal EN. In addition, an abnormality signal Fail2 from the drive measurement circuit 5 (described later) is input to the NOR circuit 437 via a level shift circuit in the communication unit 6.

[0093] The output of the AND circuit 438 and the output of the OR circuit 434 are input to an AND circuit 439, which outputs a drive signal Vg3. The output of the AND circuit 438 and the output of the inverter 435 are input to an AND circuit 440, which outputs a drive signal Vg4. That is, if there is no abnormality (specifically, the abnormality signals Fail1 and Fail2 are both at L level) and a measurement instruction is received from the higher-level system 200, when the control signal Vs is at H level and the frequency-divided signal Vs1 is at H level, the third switching element 31 and the fourth switching element 32 are alternately driven on and off in accordance with the reference clock CK0, when the control signal Vs is at L level and the frequency-divided signal Vs1 is at H level, the third switching element 31 is turned off and the fourth switching element 32 is turned on, and when the frequency-divided signal Vs1 is at L level, the third switching element 31 is turned on and the fourth switching element 32 is turned off.

[0094] A dead time is provided during which the normal drive signal Vg3 and the drive signal Vg4 are simultaneously turned off so that the third switching element 31 and the fourth switching element 32 are not simultaneously turned on. Although not shown, it is assumed here that a delay time equivalent to the dead time is provided at the rising edge of each drive signal.

[0095] 8, the reference clock CK0, the control signal Vs, and an inverted signal of the frequency-divided signal Vs1 obtained via an inverter 531 are input to an AND circuit 532. Here, the reference clock CK0 and the frequency-divided signal Vs1 are obtained from the drive measurement circuit 4 via a level shift circuit in the communication unit 6, and the control signal Vs is input from the higher-level system 200. The control signal Vs input to the drive measurement circuit 4 and the control signal Vs input to the drive measurement circuit 5 are signals of the same logic, but one of them is level-shifted.

[0096] The output of the AND circuit 532 and the frequency-divided signal Vs1 are input to an OR circuit 534. The output of the OR circuit 534 becomes a signal that drives the fifth switching element 34, and an inverted signal obtained from the output of the OR circuit 534 via an inverter 535 becomes a signal that drives the sixth switching element 35.

[0097] Although the abnormality detection circuit 536 is not essential to the present application and will not be described or illustrated in detail, the abnormality detection circuit 536 outputs an H-level abnormality signal Fail2 when the current value or voltage value detected by the AC detection unit 52, or the temperature of battery B2 detected by a temperature sensor (not shown), indicates an abnormal value. The abnormality signal Fail2 is input to an AND circuit 538 via a NOR circuit 537 together with an enable signal EN. The NOR circuit 537 also receives the abnormality signal Fail1 from the drive measurement circuit 4 via the level shift circuit of the communication unit 6.

[0098] The output of the AND circuit 538 and the output of the OR circuit 534 are input to an AND circuit 539, which outputs a drive signal Vg5. The output of the AND circuit 538 and the output of the inverter 535 are input to an AND circuit 540, which outputs a drive signal Vg6. That is, if there is no abnormality (specifically, the abnormality signals Fail1 and Fail2 are both at L level) and a measurement instruction is received from the higher-level system 200, the fifth switching element 34 and the sixth switching element 35 are alternately driven on and off in accordance with the reference clock CK0 when the control signal Vs is at H level and the frequency-divided signal Vs1 is at L level, the fifth switching element 34 is turned off and the sixth switching element 35 is turned on when the control signal Vs is at L level and the frequency-divided signal Vs1 is at L level, and the fifth switching element 34 is turned on and the sixth switching element 35 is turned off when the frequency-divided signal Vs1 is at H level.

[0099] A dead time is provided during which the normal drive signal Vg5 and the drive signal Vg6 are simultaneously turned off so that the fifth switching element 34 and the sixth switching element 35 are not simultaneously turned on. Although not shown, it is assumed here that a delay time equivalent to the dead time is provided at the rising edge of each drive signal.

[0100] FIG. 9 is a timing chart showing an example of the operation of the impedance measuring device 3 according to the third embodiment. FIG. 9 is a timing chart showing the operation of the main components of the drive control unit 43 and the drive control unit 53, and illustrates the reference clock CK0, the control signal Vs, the frequency-divided signal Vs1, the drive signals Vg3, Vg4, Vg5, and Vg6, the detection voltages Vc1 and Vc2, and the positive and negative potentials VP and VN of the capacitor 30. Although not shown, the enable signal EN is at an H level, and the abnormality signals Fail1 and Fail2 are both at an L level. The detection voltage Vc1 corresponds to the current I1 flowing through the battery B1 and the third switching element 31, and the detection voltage Vc2 corresponds to the current I2 flowing through the battery B2 and the fifth switching element 34. The operation of the impedance measuring device 3 according to the third embodiment to pass high-frequency current pulses through the batteries B1 and B2 will be described below with reference to FIG. 9 .

[0101] 9, during period T0, control signal Vs and frequency-divided signal Vs1 are both at L level, so that each drive signal Vg3 is at H level, Vg4 is at L level, Vg5 is at L level, and Vg6 is at H level. Because the third switching element 31 is on and the fourth switching element 32 is off, the positive electrode potential VP of capacitor 30 is fixed to the positive electrode potential of battery B1. Because the sixth switching element 35 is on and the fifth switching element 34 is off, the negative electrode potential VN of capacitor 30 is fixed to the negative electrode potential of battery B1 (positive electrode of battery B2). The voltage of capacitor 30 becomes the voltage of battery B1, so no battery current flows, and both detection voltages Vc1 and Vc2 are zero.

[0102] At time t0, when period T1 begins during which control signal Vs is at H level, the drive signals Vg3 and Vg4 are reference clock CK0, an inverted version of reference clock CK0, H level, and L level, respectively. Because the fifth switching element 34 is on and the sixth switching element 35 is off, the negative electrode potential VN of capacitor 30 is fixed to the negative electrode potential of battery B2, and the third switching element 31 and the fourth switching element 32 alternately switch on and off. Between times t0 and t1, drive signal Vg3 is at H level and drive signal Vg4 is at L level, so the third switching element 31 is on and the fourth switching element 32 is off, allowing currents I1 and I2 to flow and charging capacitor 30 to the sum of the voltages of batteries B1 and B2.

[0103] Next, from time t1 to t2, drive signal Vg3 is at L level and drive signal Vg4 is at H level, so third switching element 31 is in the OFF state and fourth switching element 32 is in the ON state, current I2 flows, and capacitor 30 is discharged to the voltage of battery B2. Thus, during period T1, battery B1 repeatedly discharges at the frequency of reference clock CK0, and battery B2 repeatedly charges and discharges at the frequency of reference clock CK0.

[0104] At time t3, when period T2 begins during which control signal Vs is at L level, the drive signals Vg3, Vg4, Vg5, and Vg6 are all at L level. Because the fifth switching element 34 is on and the sixth switching element 35 is off, the negative electrode potential VN of capacitor 30 remains fixed to the negative electrode potential of battery B2. Because the third switching element 31 is off and the fourth switching element 32 is on, the positive electrode potential VP of capacitor 30 is fixed to the negative electrode potential of battery B1 (positive electrode of battery B2), and capacitor 30 becomes the voltage of battery B2. No battery current flows, and both detection voltages Vc1 and Vc2 are zero.

[0105] At time t4, when the control signal Vs goes high and the frequency-divided signal Vs1 goes low, a period T3 begins, in which the drive signals Vg3 goes high, Vg4 goes low, Vg5 goes to the reference clock CK0, and Vg6 goes to the inverted version of the reference clock CK0. Since the third switching element 31 is on and the fourth switching element 32 is off, the positive electrode potential VP of the capacitor 30 is fixed to the positive electrode potential of the battery B1, and the fifth switching element 34 and the sixth switching element 35 perform a switching operation in which they are alternately turned on and off.

[0106] Between times t4 and t5, the drive signal Vg5 is at H level and the drive signal Vg6 is at L level, so the fifth switching element 34 is in the ON state and the sixth switching element 35 is in the OFF state, currents I1 and I2 flow, and capacitor 30 is charged to the sum of the voltages of batteries B1 and B2.

[0107] Next, from time t5 to t6, drive signal Vg5 is at L level and drive signal Vg6 is at H level, so fifth switching element 34 is in the OFF state and sixth switching element 35 is in the ON state, current I2 flows, and capacitor 30 is discharged to the voltage of battery B1. Thus, during period T3, battery B1 repeats charging and discharging at the frequency of reference clock CK0, and battery B2 repeats discharging at the frequency of reference clock CK0.

[0108] At time t7, when the control signal Vs goes low, the drive signals Vg3, Vg4, Vg5, Vg6 go high, Vg6, Vg3, Vg4, Vg5, Vg6, and Vg6 go high, and the period returns to T0.

[0109] As described above, batteries B1 and B2 are repeatedly charged and discharged by pulse current to capacitor 30 in accordance with control signal Vs. Current I1 from battery B1 is converted to detection voltage Vc1 by detection resistor 33 and input to current measurement unit 41 of drive measurement circuit 4, while current I2 from battery B2 is converted to detection voltage Vc2 by detection resistor 36 and input to current measurement unit 51 of drive measurement circuit 5. During measurement of AC impedance, impedance measurement device 3 repeatedly charges capacitor 30 from batteries B1 and B2 and discharges capacitor 30 to either battery B1 or B2 while control signal Vs is at a high level, and stops charging and discharging by switching operation while control signal Vs is at a low level. While this embodiment does not achieve the same high efficiency as embodiment 1, which uses inductor 14 as a storage element, it can suppress losses compared to the conventional method using a resistive element to pass a superimposed current through the battery, and achieves stable switching operation of the voltage of capacitor 30.

[0110] As described above, AC detection unit 42 receives a measurement instruction signal including information about the measurement frequency from host system 200, which has a function of calculating AC impedance, and measures the AC voltage and AC current corresponding to the measurement frequency based on the measurement results of voltage measurement units 40 and 50 and the measurement results of current measurement units 41 and 51, and outputs the results to host system 200. Furthermore, drive control unit 23 drives a plurality of switching elements (here, third switching element 31, fourth switching element 32, fifth switching element 34, and sixth switching element 35) so as to periodically change the state of transfer of electrical energy via capacitor 30 in accordance with the measurement frequency.

[0111] This periodically changes the state of electrical energy transfer between batteries B1 and B2 in accordance with the measurement frequency, allowing the AC voltage and AC current to be measured in accordance with the measurement frequency, thereby enabling the AC impedance of batteries B1 and B2 to be measured. The state of electrical energy transfer can be changed via a single capacitor 30 provided in the impedance measuring device 3, eliminating the need for both an inductor and a power storage device (capacitor) as in the method disclosed in Patent Document 2. This allows the impedance measuring device 3 to be miniaturized. In other words, the AC impedance of batteries B1 and B2 connected in series can be appropriately obtained with a small number of components.

[0112] In addition, the drive control units 43 and 53 may alternately turn on the third switching element 31 and the fourth switching element 32 at a frequency higher than the measurement frequency, and alternately turn on the fifth switching element 34 and the sixth switching element 35 at a frequency higher than the measurement frequency, so that the fourth switching element 32 and the sixth switching element 35 are not simultaneously turned on.

[0113] This shortens the time it takes to store charge at one time in the capacitor 30. In other words, a capacitor with a large capacity is no longer necessary, so the capacitor 30 can be made smaller, and ultimately the impedance measuring device 3 can be made smaller.

[0114] Furthermore, the drive control units 43 and 53 may control the third switching element 31, the fourth switching element 32, the fifth switching element 34, and the sixth switching element 35 to repeat a first energy transfer state, a second energy transfer state, and a stop state at a period corresponding to the measurement frequency. Here, the first energy transfer state is a state in which, as shown in period T3 in Fig. 9 , the third switching element 31 is fixed to the ON state, the fourth switching element 32 is fixed to the OFF state, and the fifth switching element 34 and the sixth switching element 35 are alternately turned ON at a frequency higher than the measurement frequency, thereby repeatedly charging the battery B1 when the sixth switching element 35 is ON and discharging the batteries B1 and B2 when the fifth switching element 34 is ON. 9, the second energy transfer state is a state in which the fifth switching element 34 is fixed in the on state, the sixth switching element 35 is fixed in the off state, the third switching element 31 and the fourth switching element 32 are alternately turned on at a frequency higher than the measurement frequency, and batteries B1 and B2 are repeatedly discharged when the third switching element 31 is on and battery B2 is charged when the fourth switching element 32 is on. The stopped state is a state in which batteries B1 and B2 are not charged or discharged, as shown in periods T0 and T2 in FIG.

[0115] In the first energy transfer state, battery B1 repeatedly charges and discharges, so the average current of battery B1 in the first energy transfer state is nearly zero, and the current of battery B1 cannot be measured. On the other hand, in the second energy state, battery B1 repeatedly discharges, so the current of battery B1 can be measured. Also, in the second energy transfer state, battery B2 repeatedly charges and discharges, so the average current of battery B2 in the second energy transfer state is nearly zero, and the current of battery B2 cannot be measured. On the other hand, in the first energy state, battery B2 repeatedly discharges, so the current of battery B2 can be measured. Therefore, by repeating the first energy transfer state, the stop state, and the second energy transfer state, the AC current of battery B1 and the AC current of battery B2 can each be measured. Note that this control method is useful when the voltage of battery B1 and the voltage of battery B2 are nearly the same.

[0116] In addition, by forming part or all of the drive measurement circuit 4 and part or all of the drive measurement circuit 5 in the third embodiment into integrated circuits, the device can be further miniaturized and made more versatile.

[0117] (Embodiment 4) In embodiment 3, the series-connected batteries B1 and B2 have approximately the same voltage. Therefore, in order to charge and discharge capacitor 30, which is a storage element, during the H period of control signal Vs, a switching operation is repeated in which capacitor 30 is charged from the two series-connected batteries using frequency-divided signal Vs1 and then discharged to one of the batteries. On the other hand, if batteries B1 and B2 have different voltages, for example, if the voltage of battery B1 is higher than the voltage of battery B2, a switching operation in which capacitor 30 is charged from battery B1 and then discharged to battery B2 can be repeated using the basic configuration of impedance measurement device 3 similar to that shown in FIG. 7.

[0118] The impedance measuring device according to the fourth embodiment described below has the same basic configuration as that shown in FIG. 7, but to distinguish it from the impedance measuring device 3 according to the third embodiment, the driving and measuring circuit 4, the driving and measuring circuit 5, and the communication unit 6 shown in FIG. 7 will be referred to as the driving and measuring circuit 4A, the driving and measuring circuit 5A, and the communication unit 6A, respectively.

[0119] FIG. 10 is a circuit diagram showing an example of the drive control units 43A and 53A of the impedance measuring device according to the fourth embodiment. FIG. 10 shows the internal configuration of the drive control unit 43A of the drive measurement circuit 4A, the drive control unit 53A of the drive measurement circuit 5A, and a portion of the communication unit 6A. In FIG. 10, the drive control unit 43A differs from the drive control unit 43 of FIG. 8 in that it does not include the frequency divider circuit 431, the frequency-divided signal Vs1, the inverter 433, and the OR circuit 434, and the AND circuit 432 has been reconfigured to an AND circuit 432A. Furthermore, the communication unit 6A, which shares signals with the drive control unit 53A, does not include the frequency-divided signal Vs1, and therefore has one less level shift circuit than the communication unit 6 of FIG. 8. Furthermore, the drive control unit 53A differs from the drive control unit 53 of FIG. 8 in that it does not include the inverter 531 and the OR circuit 534, and the AND circuit 532 has been reconfigured to an AND circuit 532A.

[0120] The oscillator 430 is the same as in Fig. 8 and outputs a reference clock CK0 with a duty ratio of 50% that sets the switching period. The reference clock CK0 and a control signal Vs from the upper system 200 are input to an AND circuit 432A. The output of the AND circuit 432A is input to an AND circuit 439, and the output of the AND circuit 439 becomes a drive signal Vg3 that drives the third switching element 31. An inverted signal obtained from the output of the AND circuit 432A via an inverter 435 becomes a drive signal Vg4 that drives the fourth switching element 32 via an AND circuit 440.

[0121] 8, an abnormality signal Fail1 from the abnormality detection circuit 436 is input to an AND circuit 438 together with an enable signal EN via a NOR circuit 437, and the output of the AND circuit 438 is input to AND circuits 439 and 440. That is, if there is no abnormality and a measurement instruction is received from the upper system 200, the third switching element 31 and the fourth switching element 32 are alternately driven on and off in accordance with the reference clock CK0 when the control signal Vs is at H level, and the third switching element 31 is turned off and the fourth switching element 32 is turned on when the control signal Vs is at L level.

[0122] Although not shown, a dead time is provided during which the normal drive signal Vg3 and the drive signal Vg4 are both turned off at the same time so that the third switching element 31 and the fourth switching element 32 are not both turned on at the same time, as in FIG. 8 .

[0123] As shown in the drive control unit 53A in FIG. 10, a reference clock CK0 and a control signal Vs are input to an AND circuit 532A. Here, the reference clock CK0 is obtained from the drive control unit 43A via a level shift circuit in the communication unit 6A, and the control signal Vs is input from the host system 200. The control signal Vs input to the drive measurement circuit 4 and the control signal Vs input to the drive measurement circuit 5 are signals of the same logic, but one of them is level-shifted. The output of the AND circuit 532A is input to an AND circuit 539, and the output of the AND circuit 539 becomes a drive signal Vg6 that drives the sixth switching element 35. An inverted signal obtained from the output of the AND circuit 532A via an inverter 535 becomes a drive signal Vg5 that drives the fifth switching element 34 via an AND circuit 540. The drive signals Vg5 and Vg6 are swapped compared to FIG. 8.

[0124] 8, an abnormality signal Fail2 from an abnormality detection circuit 536 is input to an AND circuit 538 together with an enable signal EN via a NOR circuit 537, and the output of the AND circuit 538 is input to AND circuits 539 and 540. That is, if there is no abnormality and a measurement instruction is received from the upper system 200, when the control signal Vs is at H level, the fifth switching element 34 and the sixth switching element 35 are alternately driven on and off in accordance with the reference clock CK0, and when the control signal Vs is at L level, the sixth switching element 35 is turned off and the fifth switching element 34 is turned on.

[0125] Although not shown, a dead time is provided in which the normal drive signal Vg5 and the drive signal Vg6 are simultaneously turned off so that the fifth switching element 34 and the sixth switching element 35 are not simultaneously turned on. Here, a delay time equivalent to the dead time is provided at the rising edge of each drive signal, as in Fig. 8 .

[0126] FIG. 11 is a timing chart showing an example of the operation of the impedance measuring device according to the fourth embodiment. FIG. 11 is a timing chart showing the operation of the main components of the drive control units 43A and 53A, including the reference clock CK0, the control signal Vs, the drive signals Vg3, Vg4, Vg5, and Vg6, the detection voltages Vc1 and Vc2, and the positive and negative potentials VP and VN of the capacitor 30. Although not shown, the enable signal EN is at an H level, and the abnormality signals Fail1 and Fail2 are both at an L level. The detection voltage Vc1 corresponds to the current I1 flowing through the battery B1 and the third switching element 31, and the detection voltage Vc2 corresponds to the current I2 flowing through the battery B2 and the fifth switching element 34. The operation of the impedance measuring device according to the fourth embodiment to pass high-frequency current pulses through the batteries B1 and B2 will be described below with reference to FIG. 11 .

[0127] 11, during period T0, control signal Vs is at L level, so that each drive signal Vg3 is at L level, Vg4 is at H level, Vg5 is at H level, and Vg6 is at L level. Because the third switching element 31 is in the OFF state and the fourth switching element 32 is in the ON state, the positive electrode potential VP of capacitor 30 is fixed to the negative electrode potential VB of battery B1. Because the sixth switching element 35 is in the OFF state and the fifth switching element 34 is in the ON state, the negative electrode potential VN of capacitor 30 is fixed to the negative electrode potential of battery B2. The voltage of capacitor 30 becomes the voltage of battery B2, so no battery current flows, and both detection voltages Vc1 and Vc2 are zero.

[0128] At time t0, when the control signal Vs enters a period T1 in which it is at H level, the drive signals Vg3 and Vg6 become the reference clock CK0, and Vg4 and Vg5 become the inverse of the reference clock CK0, resulting in a switching operation in which the third switching element 31 and the fourth switching element 32 are alternately turned on and off, and the fifth switching element 34 and the sixth switching element 35 are alternately turned on and off. Between times t0 and t1, the drive signals Vg3 and Vg6 are at H level, so the third switching element 31 and the sixth switching element 35 are in the ON state, and current I1 flows to charge the capacitor 30 to the voltage of battery B1.

[0129] Next, from time t1 to t2, drive signals Vg4 and Vg5 are at the H level, so the fourth switching element 32 and the fifth switching element 34 are turned on, current I2 flows, and capacitor 30 is discharged to the voltage of battery B2. Thus, during period T1, battery B1 repeatedly discharges at the frequency of reference clock CK0, and battery B2 repeatedly charges at the frequency of reference clock CK0.

[0130] At time t3, when the control signal Vs goes to the L level and period T2 begins, the drive signals Vg3 goes to the L level, Vg4 goes to the H level, Vg5 goes to the H level, and Vg6 goes to the L level, similar to period T0.

[0131] As described above, battery B1 is repeatedly discharged and battery B2 is repeatedly charged by the pulse current to capacitor 30 in accordance with control signal Vs. Current I1 of battery B1 is converted to detection voltage Vc1 by detection resistor 33 and input to current measurement unit 41 of drive measurement circuit 4A, and current I2 of battery B2 is converted to detection voltage Vc2 by detection resistor 36 and input to current measurement unit 51 of drive measurement circuit 5A. During AC impedance measurement, the impedance measurement device of embodiment 4 repeatedly performs a switching operation to discharge battery B1 and charge battery B2 via capacitor 30 while control signal Vs is at a high level, and stops charging and discharging through the switching operation while control signal Vs is at a low level. Compared to conventional methods that use resistive elements to pass superimposed currents through the batteries, this method reduces losses and achieves switching operation with a stable voltage across capacitor 30.

[0132] As described above, the drive control units 43A and 53A may control the third switching element 31, the fourth switching element 32, the fifth switching element 34, and the sixth switching element 35 to alternate between a first energy transfer state and a stopped state at a cycle corresponding to the measurement frequency. Here, the first energy transfer state is a state in which, as shown in period T1 in Fig. 11 , the third switching element 31 and the fourth switching element 32 are alternately turned on at a frequency higher than the measurement frequency, the fifth switching element 34 and the sixth switching element 35 are alternately turned on at a frequency higher than the measurement frequency, the switching phase of the third switching element 31 and the switching phase of the sixth switching element 35 are in phase, the switching phase of the fourth switching element 32 and the switching phase of the fifth switching element 34 are in phase, and the discharging of battery B1 and charging battery B2 via capacitor 30 are repeated, or the charging of battery B1 and discharging battery B2 are repeated. The stopped state is a state in which the batteries B1 and B2 are not charged or discharged, as shown in periods T0 and T2 in FIG.

[0133] Because battery B1 is repeatedly discharged, the current of battery B1 can be measured, and because battery B2 is repeatedly charged, the current of battery B2 can be measured. Therefore, by repeating the first energy transfer state and the stopped state, the AC current of battery B1 and the AC current of battery B2 can be measured, respectively. Note that this control method is useful when the voltage of battery B1 is higher than the voltage of battery B2. When the voltage of battery B1 is lower than the voltage of battery B2, the above-mentioned charge / discharge relationship is reversed.

[0134] In addition, by forming part or all of the drive measurement circuit 4A and part or all of the drive measurement circuit 5A of the fourth embodiment into integrated circuits, the device can be further miniaturized and made more versatile.

[0135] (Other Embodiments) As described above, the embodiments have been described as examples of the technology according to the present disclosure. However, the technology according to the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. For example, the following modifications are also included in one embodiment of the present disclosure.

[0136] For example, the present disclosure can be realized not only as a drive and measurement circuit, but also as a drive and measurement method including steps (processing) performed by components that make up the drive and measurement circuit.

[0137] FIG. 12 is a flowchart showing an example of a driving and measuring method according to another embodiment.

[0138] The driving measurement method is a driving measurement method for controlling an impedance measurement device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measurement device comprising: a storage element that stores or releases electric energy; a switching circuit that includes a plurality of switching elements and that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, and the driving measurement method includes receiving a measurement instruction signal including information on a measurement frequency from a host system having a function of calculating the AC impedance, as shown in FIG. a driving step (step S12) of driving a plurality of switching elements so as to periodically change the state of movement of electrical energy through the storage elements in accordance with the measurement frequency; a current measurement step (step S13) of measuring the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement step (step S14) of measuring the voltage of the first battery and the voltage of the second battery; and an AC detection step (step S15) of measuring AC voltage and AC current according to the measurement frequency based on the measurement result in the voltage measurement step and the measurement result in the current measurement step, and outputting the results to a higher-level system.

[0139] For example, the present disclosure can be realized as a program for causing a computer (processor) to execute steps included in the driving measurement method. Furthermore, the present disclosure can be realized as a non-transitory computer-readable recording medium, such as a CD-ROM, on which the program is recorded.

[0140] For example, when the present disclosure is realized as a program (software), each step is performed by running the program using hardware resources such as a computer's CPU, memory, input / output circuits, etc. In other words, each step is performed by the CPU acquiring data from memory or input / output circuits, etc., performing calculations, and outputting the calculation results to memory or input / output circuits, etc.

[0141] In the above-described embodiments, each component included in the drive measurement circuit may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may also be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0142] Some or all of the functions of the drive and measurement circuits according to the above embodiments are typically implemented as an LSI, which is an integrated circuit. These may be implemented individually on a single chip, or some or all of them may be integrated on a single chip. Furthermore, the integrated circuit is not limited to an LSI, and may be implemented using a dedicated circuit or a general-purpose processor. It is also possible to use an FPGA (Field Programmable Gate Array), which can be programmed after LSI manufacturing, or a reconfigurable processor, which can reconfigure the connections and settings of circuit cells within an LSI.

[0143] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that each component included in the drive and measurement circuit may be integrated using that technology.

[0144] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0145] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0146] (Technology 1) A driving measurement circuit for controlling an impedance measurement device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measurement device comprising: a storage element that stores or releases electric energy; a switching circuit that includes a plurality of switching elements and that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, and the driving measurement circuit controls the current of the first battery based on the detection result of the current detection means. a current measuring unit that measures the current of the first battery and the current of the second battery; a voltage measuring unit that measures the voltage of the first battery and the voltage of the second battery; an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from a host system having a function of calculating AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement results of the voltage measuring unit and the current measuring unit, and outputs the measured values ​​to the host system; and a drive control unit that drives the plurality of switching elements so as to periodically change the state of movement of electrical energy through the storage elements in accordance with the measurement frequency.

[0147] According to this method, the state of electrical energy transfer between the first battery and the second battery is periodically changed in accordance with the measurement frequency, so that the AC voltage and AC current corresponding to the measurement frequency can be measured, and the AC impedance of the first battery and the second battery can be measured. In this case, the state of electrical energy transfer can be changed via a single storage element such as an inductor or capacitor provided in the impedance measuring device, eliminating the need for both an inductor and a storage device (capacitor) as in the method disclosed in Patent Document 2. This allows for the miniaturization of the impedance measuring device.

[0148] In addition, since the AC impedance can be measured regardless of the magnitude of the voltage of the first battery and the voltage of the second battery, restrictions on use are relaxed. Furthermore, since current flows constantly between the first battery and the second battery so as to charge and discharge without a break, measurement time is shortened and continuous measurement is possible.

[0149] (Technology 2) A driving and measuring circuit according to Technology 1, wherein the first battery and the second battery are each composed of two or more battery cells, and the voltage measuring unit simultaneously measures the voltages of the two or more battery cells.

[0150] This allows the voltage of the first battery and the voltage of the second battery to be measured in a short time.

[0151] (Technology 3) A drive and measurement circuit according to Technology 1 or 2, in which the storage element is an inductor, the switching circuit has a first switching element that forms a first loop together with the first battery and the inductor, and a second switching element that forms a second loop together with the second battery and the inductor, and the drive control unit alternately turns on the first switching element and the second switching element at a frequency higher than the measurement frequency.

[0152] According to this, by alternately turning on the first switching element and the second switching element at a frequency higher than the measurement frequency, the time during which current flows through the inductor at one time can be shortened. In other words, since a large current is less likely to flow through the inductor, the inductor can be made smaller, which in turn makes it possible to make the impedance measuring device more compact.

[0153] (Technology 4) A drive and measurement circuit according to Technology 3, wherein the current detection means has a first detection resistor connected between the first battery and the first switching element, and a second detection resistor connected between the second battery and the second switching element.

[0154] According to this, the current of the first battery can be detected by detecting the current flowing through the first detection resistor, and the current of the second battery can be detected by detecting the current flowing through the second detection resistor.

[0155] (Technology 5) A drive and measurement circuit according to Technology 3, wherein the current detection means includes one of a first detection resistor connected between the first battery and the first switching element and a second detection resistor connected between the second battery and the second switching element, and a third detection resistor connected in series with the inductor.

[0156] According to this, the current of one of the first and second batteries can be detected by detecting the current flowing through one of the first and second detection resistors. Also, since the current flowing through the third detection resistor is the difference between the current flowing through the second battery and the current flowing through the first battery, the current of the other of the first and second batteries can be detected by calculating the sum of the current flowing through the one detection resistor and the current flowing through the third detection resistor.

[0157] (Technology 6) A drive measurement circuit described in any one of Technologies 3 to 5, wherein the drive control unit controls the on-time of the first switching element and the on-time of the second switching element so as to repeat, at a period corresponding to the measurement frequency, a first energy transfer state in which a discharge current is flowed from the first battery when the first switching element is on and a charge current is flowed to the second battery when the second switching element is on, and a second energy transfer state in which a discharge current is flowed from the second battery when the second switching element is on and a charge current is flowed to the first battery when the first switching element is on.

[0158] According to this, by lengthening the ON time of the second switching element, it is possible to start a discharge current flow from the second battery, thereby switching from the first energy transfer state to the second energy transfer state, and by lengthening the ON time of the first switching element, it is possible to start a discharge current flow from the first battery, thereby switching from the second energy transfer state to the first energy transfer state.

[0159] (Technology 7) A drive measurement circuit according to Technology 6, wherein the drive control unit limits the peak value of the discharge current from the first battery to a predetermined value in the first energy transfer state, and limits the peak value of the discharge current from the second battery to a predetermined value in the second energy transfer state.

[0160] This makes it possible to limit the discharge current from the first battery and the discharge current from the second battery, thereby suppressing switching loss that occurs during switching.

[0161] (Technology 8) A drive and measurement circuit according to any one of technologies 3 to 7, wherein the switching circuit has a current interruption means connected in series with the inductor, and the drive control unit interrupts the current flowing to the current interruption means when the detection result of the current detection means exceeds a predetermined amount.

[0162] This allows current to be cut off when an overcurrent flows.

[0163] (Technology 9) A drive and measurement circuit according to Technology 1 or 2, wherein the storage element is a capacitor, and the switching circuit has a third switching element connected between a positive electrode of the first battery and a positive electrode of the capacitor, a fourth switching element connected between a negative electrode of the first battery and a positive electrode of the capacitor, a fifth switching element connected between a negative electrode of the second battery and a negative electrode of the capacitor, and a sixth switching element connected between a positive electrode of the second battery and a negative electrode of the capacitor, and the drive control unit alternately turns on the third switching element and the fourth switching element at a frequency higher than the measurement frequency and alternately turns on the fifth switching element and the sixth switching element at a frequency higher than the measurement frequency, so that the fourth switching element and the sixth switching element are not simultaneously turned on.

[0164] According to this, by alternately turning on the third switching element and the fourth switching element at a frequency higher than the measurement frequency and by alternately turning on the fifth switching element and the sixth switching element at a frequency higher than the measurement frequency, it is possible to shorten the time it takes to store charge in the capacitor at one time. In other words, since a capacitor with a large capacity is not required, the capacitor can be made smaller, and therefore the impedance measuring device can be made smaller.

[0165] (Technology 10) A drive and measurement circuit according to Technology 9, wherein the current detection means has a first detection resistor connected between the first battery and the third switching element, and a second detection resistor connected between the second battery and the fifth switching element.

[0166] According to this, the current of the first battery can be detected by detecting the current flowing through the first detection resistor, and the current of the second battery can be detected by detecting the current flowing through the second detection resistor.

[0167] (Technology 11) The drive control unit includes: a first energy transfer state in which the third switching element is fixed to an on state, the fourth switching element is fixed to an off state, and the fifth switching element and the sixth switching element are alternately turned on at a frequency higher than the measurement frequency, and the first battery is charged when the sixth switching element is on, and the first battery and the second battery are discharged when the fifth switching element is on; and a second energy transfer state in which the fifth switching element is fixed to an on state, the sixth switching element is fixed to an off state, and the third switching element and the sixth switching element are alternately turned on at a frequency higher than the measurement frequency, and the first energy transfer state is repeated. 11. The driving and measuring circuit according to technique 9 or 10, wherein the third switching element, the fourth switching element, the fifth switching element, and the sixth switching element are controlled so as to alternately turn on the third switching element and a fourth switching element at a frequency higher than the measurement frequency, and to repeat, in a cycle corresponding to the measurement frequency, a second energy transfer state in which the first battery and the second battery are discharged when the third switching element is on and the second battery is charged when the fourth switching element is on, and a stop state in which the first battery and the second battery are not charged or discharged.

[0168] According to this, in the first energy transfer state, the first battery repeatedly charges and discharges, so the average current of the first battery in the first energy transfer state is approximately zero, and the current of the first battery cannot be measured. On the other hand, in the second energy state, the first battery repeatedly discharges, so the current of the first battery can be measured. Also, in the second energy transfer state, the second battery repeatedly charges and discharges, so the average current of the second battery in the second energy transfer state is approximately zero, and the current of the second battery cannot be measured. On the other hand, in the first energy state, the second battery repeatedly discharges, so the current of the second battery can be measured. Therefore, by repeating the first energy transfer state, the stop state, and the second energy transfer state, the AC current of the first battery and the AC current of the second battery can each be measured. Note that this control method is useful when the voltage of the first battery and the voltage of the second battery are approximately the same.

[0169] (Technology 12) The drive measurement circuit according to claim 9 or 10, wherein the drive control unit alternately turns on the third switching element and the fourth switching element at a frequency higher than the measurement frequency, alternately turns on the fifth switching element and the sixth switching element at a frequency higher than the measurement frequency, makes the switching phase of the third switching element and the switching phase of the sixth switching element the same, makes the switching phase of the fourth switching element and the switching phase of the fifth switching element the same, and controls the third switching element, the fourth switching element, the fifth switching element, and the sixth switching element so as to repeat, at a period corresponding to the measurement frequency, a first energy transfer state in which the first battery is repeatedly discharged and the second battery is repeatedly charged, or the first battery is repeatedly charged and the second battery is repeatedly discharged, and a stopped state in which the first battery and the second battery are not charged or discharged, via the capacitor.

[0170] According to this, the current of the first battery can be measured because the first battery is repeatedly discharged, and the current of the second battery can be measured because the second battery is repeatedly charged. Therefore, by repeating the first energy transfer state and the stopped state, the AC current of the first battery and the AC current of the second battery can be measured, respectively. Note that this control method is useful when the voltage of the first battery is higher than the voltage of the second battery.

[0171] (Technology 13) The drive and measurement circuit according to any one of technologies 1 to 12, wherein at least the current measurement unit, the voltage measurement unit, the AC detection unit, and the drive control unit are integrated into an integrated circuit.

[0172] In this way, the current measuring section, voltage measuring section, AC detecting section, and drive control section may be integrated into an integrated circuit.

[0173] (Technology 14) An impedance measuring device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measuring device comprising: a storage element that stores or releases electric energy; a switching circuit consisting of a plurality of switching elements that intermittently transfers electric energy between the first battery and the second battery via the storage element; current detection means that detects the current of the first battery and the current of the second battery; and a drive measurement circuit, wherein the drive measurement circuit comprises: a current measurement unit that measures the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement unit that measures the voltage of the first battery and the voltage of the second battery; an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from a higher-level system having a function of calculating AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit and outputs the results to the higher-level system; and a drive control unit that drives the plurality of switching elements to periodically change the state of transfer of electric energy via the storage element in accordance with the measurement frequency.

[0174] This makes it possible to provide a small-sized impedance measuring device.

[0175] (Technology 15) An impedance measuring device is provided which measures the AC impedance of a first battery and a second battery connected in series, a driving and measuring circuit for controlling the impedance measuring device, and a host system having a function of calculating the AC impedance, wherein the impedance measuring device is provided with a storage element which stores or releases electric energy, a switching circuit which is made up of a plurality of switching elements and which intermittently transfers electric energy between the first battery and the second battery via the storage element, and a current detecting means which detects the current of the first battery and the current of the second battery, and the driving and measuring circuit is provided with an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from the upper system, measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement results of the voltage measurement unit and the current measurement unit, and outputs the measured values ​​to the upper system; and a drive control unit that drives the plurality of switching elements so as to periodically change the state of transfer of electrical energy through the storage elements according to the measurement frequency.

[0176] This makes it possible to provide a small-sized impedance measurement system.

[0177] (Technology 16) A driving measurement method for controlling an impedance measurement device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measurement device comprising: a storage element that stores or releases electric energy; a switching circuit that includes a plurality of switching elements and that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, and the driving measurement method includes receiving measurement information including information on a measurement frequency from a host system having a function of calculating the AC impedance. a current measurement step of measuring a current of the first battery and a current of the second battery based on a detection result of the current detection means; a voltage measurement step of measuring a voltage of the first battery and a voltage of the second battery; and an AC detection step of measuring an AC voltage and an AC current according to the measurement frequency based on the measurement result of the voltage measurement step and the measurement result of the current measurement step, and outputting the measured AC voltage and AC current to the higher-level system.

[0178] This provides a driving measurement method that allows the impedance measuring device to be miniaturized.

[0179] The present disclosure is useful as an impedance measuring device for diagnosing battery deterioration.

[0180] REFERENCE SIGNS LIST 1, 1A, 3 Impedance measuring device 2, 2A, 4, 4A, 5, 5A Drive and measurement circuit 6, 6A, 224 Communication unit 11 First switching element 12 Second switching element 13 Current interruption means 14 Inductor 15, 16, 17, 33, 36 Detection resistor 20, 40, 50 Voltage measurement unit 21, 21A, 41, 51 Current measurement unit 22, 42, 52 AC detection unit 23, 43, 43A, 53, 53A Drive control unit 30 Capacitor 31 Third switching element 32 Fourth switching element 34 Fifth switching element 35 Sixth switching element 100 Impedance measurement system 200 Upper system 210 Adder 220 Signal generation unit 221 Conversion unit 222 Integration unit 223 Holding unit 230, 430 Oscillator 231, 232 Reference voltage source 233, 234 Comparator 235, 434, 534 OR circuit 236 SR latch 237, 238 Switch circuit 239, 436, 536 Abnormality detection circuit 240, 433, 435, 531, 535 Inverter 241, 242, 243, 432, 432A, 438, 439, 440, 532, 532A, 538, 539, 540 AND circuit 431 Frequency divider circuit 437, 537 NOR circuit B1, B2 Battery

Claims

1. A drive measurement circuit for controlling an impedance measurement device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measurement device comprising: a storage element that stores or releases electric energy; a switching circuit consisting of a plurality of switching elements that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, the drive measurement circuit comprising: a current measurement unit that measures the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement unit that measures the voltage of the first battery and the voltage of the second battery; an AC detection unit that receives a measurement instruction signal including information on a measurement frequency from a host system that has a function of calculating AC impedance, and measures an AC voltage and an AC current corresponding to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit and outputs them to the host system; and a drive control unit that drives the plurality of switching elements so as to periodically change the state of transfer of electric energy via the storage element in accordance with the measurement frequency. A drive and measurement circuit comprising:

2. The drive measurement circuit according to claim 1, wherein the first battery and the second battery are each composed of two or more battery cells, and the voltage measurement unit simultaneously measures the voltages of the two or more battery cells.

3. A drive and measurement circuit as claimed in claim 1 or 2, wherein the storage element is an inductor, the switching circuit has a first switching element that forms a first loop together with the first battery and the inductor, and a second switching element that forms a second loop together with the second battery and the inductor, and the drive control unit alternately turns on the first switching element and the second switching element at a frequency higher than the measurement frequency.

4. A drive and measurement circuit as claimed in claim 3, wherein said current detection means comprises a first detection resistor connected between said first battery and said first switching element, and a second detection resistor connected between said second battery and said second switching element.

5. A drive and measurement circuit as claimed in claim 3, wherein said current detection means comprises one of a first detection resistor connected between said first battery and said first switching element and a second detection resistor connected between said second battery and said second switching element, and a third detection resistor connected in series with said inductor.

6. A drive measurement circuit as described in any one of claims 3 to 5, wherein the drive control unit controls the on-time of the first switching element and the on-time of the second switching element so as to repeat, at a period corresponding to the measurement frequency, a first energy transfer state in which a discharge current is repeatedly flowing from the first battery when the first switching element is on and a charge current is repeatedly flowing to the second battery when the second switching element is on, and a second energy transfer state in which a discharge current is repeatedly flowing from the second battery when the second switching element is on and a charge current is repeatedly flowing to the first battery when the first switching element is on.

7. A drive measurement circuit as described in claim 6, wherein the drive control unit limits the peak value of the discharge current from the first battery to a predetermined value in the first energy transfer state, and limits the peak value of the discharge current from the second battery to a predetermined value in the second energy transfer state.

8. A drive and measurement circuit as claimed in any one of claims 3 to 7, wherein the switching circuit has a current interruption means connected in series with the inductor, and the drive control unit interrupts the current flowing to the current interruption means when the detection result of the current detection means exceeds a predetermined amount.

9. The drive and measurement circuit according to claim 1 or 2, wherein the storage element is a capacitor, the switching circuit has a third switching element connected between the positive electrode of the first battery and the positive electrode of the capacitor, a fourth switching element connected between the negative electrode of the first battery and the positive electrode of the capacitor, a fifth switching element connected between the negative electrode of the second battery and the negative electrode of the capacitor, and a sixth switching element connected between the positive electrode of the second battery and the negative electrode of the capacitor, and the drive control unit alternately turns on the third switching element and the fourth switching element at a frequency higher than the measurement frequency and alternately turns on the fifth switching element and the sixth switching element at a frequency higher than the measurement frequency, so that the fourth switching element and the sixth switching element are not simultaneously turned on.

10. A drive and measurement circuit as claimed in claim 9, wherein said current detection means comprises a first detection resistor connected between said first battery and said third switching element, and a second detection resistor connected between said second battery and said fifth switching element.

11. The drive control unit has: a first energy transfer state in which the third switching element is fixed to the on state, the fourth switching element is fixed to the off state, and the fifth switching element and the sixth switching element are alternately turned on at a frequency higher than the measurement frequency, repeating charging the first battery when the sixth switching element is on and discharging the first battery and the second battery when the fifth switching element is on; a second energy transfer state in which the fifth switching element is fixed to the on state, the sixth switching element is fixed to the off state, and the third switching element and the fourth switching element are alternately turned on at a frequency higher than the measurement frequency, repeating discharging the first battery and the second battery when the third switching element is on and charging the second battery when the fourth switching element is on; and a stop state in which the first battery and the second battery are not charged or discharged.

11. The drive measurement circuit according to claim 9, wherein the third switching element, the fourth switching element, the fifth switching element, and the sixth switching element are controlled so that the above-mentioned operation is repeated at a period corresponding to the measurement frequency.

12. The drive measurement circuit according to claim 9 or 10, wherein the drive control unit controls the third switching element, the fourth switching element, the fifth switching element, and the sixth switching element to alternately turn on at a frequency higher than the measurement frequency, alternately turn on at a frequency higher than the measurement frequency, make the switching phase of the third switching element and the switching phase of the sixth switching element the same, make the switching phase of the fourth switching element and the switching phase of the fifth switching element the same, and repeat a first energy transfer state in which the first battery is repeatedly discharged and the second battery is repeatedly charged via the capacitor, or the first battery is repeatedly charged and the second battery is repeatedly discharged, and a stop state in which the first battery and the second battery are not charged or discharged, at a period corresponding to the measurement frequency.

13. A drive and measurement circuit according to any one of claims 1 to 12, wherein at least the current measurement section, the voltage measurement section, the AC detection section, and the drive control section are integrated into an integrated circuit.

14. An impedance measuring device for measuring the AC impedance of a first battery and a second battery connected in series, comprising: a storage element for storing or discharging electric energy; a switching circuit consisting of a plurality of switching elements for intermittently transferring electric energy between the first battery and the second battery via the storage element; current detection means for detecting the current of the first battery and the current of the second battery; and a drive measurement circuit, wherein the drive measurement circuit comprises: a current measurement unit for measuring the current of the first battery and the current of the second battery based on the detection result of the current detection means; a voltage measurement unit for measuring the voltage of the first battery and the voltage of the second battery; an AC detection unit for receiving a measurement instruction signal including information on a measurement frequency from a host system having a function of calculating AC impedance, and measuring an AC voltage and an AC current corresponding to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit, and outputting the measured values to the host system; and a drive control unit for driving the plurality of switching elements so as to periodically change the state of transfer of electric energy via the storage element in accordance with the measurement frequency. An impedance measuring device comprising:

15. An impedance measuring device comprising: an impedance measuring device for measuring the AC impedance of a first battery and a second battery connected in series; a driving measurement circuit for controlling the impedance measuring device; and a host system having a function for calculating the AC impedance, wherein the impedance measuring device comprises: a storage element for storing or discharging electric energy; a switching circuit consisting of a plurality of switching elements for intermittently transferring electric energy between the first battery and the second battery via the storage element; and current detection means for detecting the current of the first battery and the current of the second battery, wherein the driving measurement circuit comprises: a current measurement unit for measuring the current of the first battery and the current of the second battery based on the detection result of the current detection unit; a voltage measurement unit for measuring the voltage of the first battery and the voltage of the second battery; and an AC detection unit for receiving a measurement instruction signal including information on a measurement frequency from the host system, and measuring the AC voltage and AC current corresponding to the measurement frequency based on the measurement result of the voltage measurement unit and the measurement result of the current measurement unit, and outputting the results to the host system. a drive control unit that drives the plurality of switching elements so as to periodically change a state of transfer of electrical energy via the storage element in accordance with the measurement frequency.

16. A driving and measuring method for controlling an impedance measuring device that measures the AC impedance of a first battery and a second battery connected in series, the impedance measuring device comprising: a storage element that stores or releases electric energy; a switching circuit consisting of a plurality of switching elements that intermittently transfers electric energy between the first battery and the second battery via the storage element; and current detection means that detects the current of the first battery and the current of the second battery, the driving and measuring method comprising: a power receiving step of receiving a measurement instruction signal including information on a measurement frequency from a host system having a function of calculating AC impedance; a driving step of driving the plurality of switching elements so as to periodically change the transfer state of electric energy via the storage element in accordance with the measurement frequency; a current measuring step of measuring the current of the first battery and the current of the second battery based on the detection result of the current detection means; and a voltage measuring step of measuring the voltage of the first battery and the voltage of the second battery. an AC detection step of measuring an AC voltage and an AC current according to the measurement frequency based on the measurement results in the voltage measurement step and the current measurement step, and outputting the AC voltage and the AC current to the host system.

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