Battery monitoring device and battery monitoring method

Abstract

A battery monitoring device (201) comprises a signal generating unit that generates a control signal for controlling a first measuring circuit (1z) to which a first battery assembly (1) obtained by dividing a plurality of batteries connected in series is connected, and a second measuring circuit (2z) to which a second battery assembly (2) obtained by dividing the plurality of batteries is connected, and an impedance calculating unit (15) that calculates the AC impedance of each of the plurality of batteries on the basis of a measured current value flowing through the first measuring circuit (1z) and the voltage value of each battery included in the first battery assembly (1), and a measured current value flowing through the second measuring circuit (2z) and the voltage value of each battery included in the second battery assembly (2), wherein: the first measuring circuit (1z) includes a first switch; the second measuring circuit (2z) includes a second switch; and the signal generating unit generates a control signal for exclusively turning on the first switch and the second switch.

Description

Battery monitoring device and battery monitoring method

[0001] The present disclosure relates to a battery monitoring device and a battery monitoring method.

[0002] In recent years, applications using secondary batteries, such as electric vehicles and other environmentally friendly vehicles, and storage batteries for a stable supply of renewable energy, have been rapidly increasing. Due to their high energy density, lithium-ion batteries (LiBs) are often adopted as secondary batteries. Lithium-ion batteries are known to deteriorate rapidly due to overcharging, overdischarging, temperature, and other factors, and in the worst case scenario, can cause smoke, fire, or even explosion. Therefore, lithium-ion batteries are typically incorporated into a battery management system (BMS) and placed under appropriate control.

[0003] Recently, studies have been conducted to improve the accuracy of battery control by detecting battery deterioration or internal temperature by measuring the AC impedance of the battery. For example, Patent Document 1 discloses the use of an AC impedance method in which the voltage and current are measured while sweeping an AC signal to each battery in a battery pack.

[0004] International Publication No. 2020 / 003841

[0005] However, the method of Patent Document 1 has a problem in that the circuit that measures the AC impedance of the battery generates heat.

[0006] Therefore, the present disclosure provides a battery monitoring device and a battery monitoring method that can suppress heat generation in a circuit that measures the AC impedance of a battery.

[0007] A battery monitoring device according to one aspect of the present disclosure includes a signal generation unit that generates control signals to control a first measurement circuit to which a first assembled battery is connected, and a second measurement circuit to which the second assembled battery is connected, out of a first assembled battery and a second assembled battery that are formed by dividing a plurality of batteries connected in series, and an impedance calculation unit that calculates an AC impedance of each of the plurality of batteries based on a first current value flowing through the first measurement circuit and a voltage value of each battery included in the first assembled battery, and a second current value flowing through the second measurement circuit and a voltage value of each battery included in the second assembled battery, which are measured at different times, wherein the first measurement circuit has a first switch connected in series with the first assembled battery, and the second measurement circuit has a second switch connected in series with the second assembled battery, and the signal generation unit generates the control signal to exclusively turn on the first switch and the second switch.

[0008] A battery monitoring method according to one aspect of the present disclosure generates a control signal to control a first measurement circuit to which a first assembled battery is connected, and a second measurement circuit to which the second assembled battery is connected, of a first assembled battery and a second assembled battery formed by dividing a plurality of batteries connected in series, and calculates an AC impedance of each of the plurality of batteries based on a first current value flowing through the first measurement circuit and a voltage value of each battery included in the first assembled battery, and a second current value flowing through the second measurement circuit and a voltage value of each battery included in the second assembled battery, which are measured at different times, the first measurement circuit having a first switch connected in series with the first assembled battery, and the second measurement circuit having a second switch connected in series with the second assembled battery, and the control signal is generated to exclusively turn on the first switch and the second switch.

[0009] According to one aspect of the present disclosure, it is possible to realize a battery monitoring device or the like that can suppress heat generation in a circuit that measures the AC impedance of a battery.

[0010] FIG. 1 is a diagram showing the configuration of a battery monitoring system according to a first embodiment. FIG. 2 is a diagram showing the voltage waveform of a control signal pulse applied to a transistor according to the first embodiment. FIG. 3 is a diagram showing the configuration of a battery monitoring system according to a second embodiment. FIG. 4 is a diagram showing the configuration of a battery monitoring system according to a third embodiment. FIG. 5 is a flowchart showing operations related to fault diagnosis and calibration in the battery monitoring systems according to the respective embodiments. FIG. 6 is a diagram showing the configuration of a battery monitoring system in a conventional example. FIG. 7 is a diagram showing the configuration of a battery monitoring system in a comparative example.

[0011] (Background to the Invention of the Present Disclosure) Prior to describing the present disclosure, the background to the invention of the present disclosure will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a diagram showing the configuration of a battery monitoring system in a conventional example. Fig. 7 is a diagram showing the configuration of a battery monitoring system in a comparative example.

[0012] 6 and 7 show battery monitoring systems for a battery pack in which 18 batteries, consisting of batteries 1a-1i and batteries 2a-2i, are connected in series. The battery monitoring system shown in FIG. 6 includes a first load resistor 3, a first transistor 5, and a first shunt resistor 7 as a circuit for measuring the AC impedance of the batteries, and an impedance measurement integrated circuit 901 including multiple voltage measurement units and an impedance calculation unit as an integrated circuit for measuring the impedance. In other words, the battery monitoring system of FIG. 6 has one integrated circuit. The battery monitoring system shown in FIG. 7 includes an impedance measurement integrated circuit 902 including a first load resistor 3, a first transistor 5, and a first shunt resistor 7 as a circuit for measuring the AC impedance of the first battery pack 1, and multiple voltage measurement units and an impedance calculation unit as an integrated circuit for measuring the impedance. Also, the battery monitoring system of FIG. 7 includes an impedance measurement integrated circuit 903 including a second load resistor 4, a second transistor 6, and a second shunt resistor 8 as a circuit for measuring the complex impedance of the second battery pack 2, and multiple voltage measurement units and an impedance calculation unit as an integrated circuit for measuring the impedance. In other words, the battery monitoring system of FIG. 7 has two integrated circuits.

[0013] As described in the "Background Art" above, lithium-ion batteries are widely used as secondary batteries. However, it is known that lithium-ion batteries deteriorate rapidly due to overcharging, over-discharging, temperature, etc., and they are usually incorporated into a BMS and placed under appropriate control before use.

[0014] In order to improve the accuracy of battery control by detecting battery deterioration, internal temperature, etc., Patent Document 1, for example, proposes using an AC impedance method to measure the voltage and current of the battery.

[0015] However, when the impedance measurement circuit proposed in Patent Document 1 measures the impedance of multiple batteries connected in series (see, for example, FIG. 6 ), heat is generated in the first load resistor 3 from the total voltage of the multiple batteries and the impedance measurement current. This makes it necessary to dissipate the heat generated during the measurement, which requires, for example, adding a heat dissipation function such as a fan or mounting the first load resistor 3 in parallel to dissipate the heat generated in the load resistor, resulting in an increase in circuit size.

[0016] 7, it is possible to reduce heat generation in the first load resistor 3 and the second load resistor 4, but an impedance measurement circuit harness is required for each required integrated circuit. Therefore, the circuit size increases scalably as the number of series-connected batteries increases. In other words, it is difficult to simultaneously suppress heat generation and reduce the circuit size in the comparative example shown in FIG.

[0017] Therefore, the inventors of the present application have conducted extensive research into a battery monitoring device and a battery monitoring method that can suppress heat generation in the circuit that measures the AC impedance of a battery, and have devised the battery monitoring device and battery monitoring method described below.The inventors have also devised a battery monitoring device and battery monitoring method that can reduce the size of the AC impedance measurement circuit for a battery pack in which many batteries are connected in series.

[0018] A battery monitoring device according to a first aspect of the present disclosure includes a signal generation unit that generates control signals to control a first measurement circuit to which a first assembled battery is connected, and a second measurement circuit to which the second assembled battery is connected, out of a first assembled battery and a second assembled battery that are formed by dividing a plurality of batteries connected in series, and an impedance calculation unit that calculates the AC impedance of each of the plurality of batteries based on a first current value flowing through the first measurement circuit and a voltage value of each battery included in the first assembled battery, and a second current value flowing through the second measurement circuit and a voltage value of each battery included in the second assembled battery, which are measured at different times, wherein the first measurement circuit has a first switch connected in series with the first assembled battery, and the second measurement circuit has a second switch connected in series with the second assembled battery, and the signal generation unit generates the control signal to exclusively turn on the first switch and the second switch.

[0019] This allows the timing of impedance measurements for the first assembled battery and the second assembled battery to be independent (different), which results in the heat generation time being dispersed and suppresses heat generation in the load resistor. Therefore, the battery monitoring device can suppress heat generation in the circuit that measures the AC impedance of the battery.

[0020] Furthermore, for example, a battery monitoring device according to a second aspect may be the battery monitoring device according to the first aspect, wherein the first measurement circuit has a first transistor connected to the first assembled battery as the first switch, the second measurement circuit has a second transistor connected to the second assembled battery as the second switch, and the control signal is a signal for operating the first transistor and the second transistor in a time-division manner within independent periods.

[0021] In this way, since the first transistor and the second transistor are used, the timing of the impedance measurement can be easily made independent.

[0022] Furthermore, for example, a battery monitoring device according to a third aspect may be a battery monitoring device according to the first or second aspect, wherein the first control signal output to the first transistor and the second control signal output to the second transistor are rectangular wave signals that can be controlled to any period, and the signal generating unit sets a duty ratio of the first control signal according to the period of the first control signal, and sets a duty ratio of the second control signal according to the period of the second control signal.

[0023] This makes it possible to suppress the heat generation in the load resistor from varying with frequency when the frequency of the control signal is changed (for example, swept).Furthermore, for example, by setting the duty ratio so that the amount of heat generated is small, it is possible to reduce the amount of heat generated itself.

[0024] Furthermore, for example, a battery monitoring device according to a fourth aspect is a battery monitoring device according to any one of the first to third aspects, and the first measurement circuit and the second measurement circuit may share some harnesses.

[0025] This reduces the number of harnesses required to configure the first measurement circuit and the second measurement circuit, thereby achieving both heat suppression and a reduction in circuit size.

[0026] Furthermore, for example, a battery monitoring device according to a fifth aspect may be the battery monitoring device according to the fourth aspect, wherein the first measurement circuit has a first load resistor for measuring the AC impedance and a first shunt resistor for measuring current, which are connected to the first assembled battery, the second measurement circuit has a second load resistor for measuring the AC impedance and a second shunt resistor for measuring current, which are connected to the second assembled battery, and the common part of the harness may be arranged to connect the negative terminal of the first assembled battery and the positive terminal of the second assembled battery to the first load resistor and the second load resistor.

[0027] This makes it possible to reduce the number of harnesses for connecting the negative terminal of the first assembled battery and the positive terminal of the second assembled battery to the first load resistor and the second load resistor.

[0028] Furthermore, for example, a battery monitoring device according to a sixth aspect is the battery monitoring device according to the fourth aspect, wherein the first measurement circuit includes the first assembled battery, a first load resistor connected to the first assembled battery for measuring the AC impedance, and a first shunt resistor for measuring current; the second measurement circuit includes the second assembled battery, and a second load resistor connected to the second assembled battery for measuring the AC impedance, and a second shunt resistor for measuring current; and the first load resistor and the second load resistor may be provided in a common portion of the harness.

[0029] This allows the first measurement circuit and the second measurement circuit to share a load resistor, further reducing the circuit size.

[0030] Furthermore, for example, a battery monitoring device according to a seventh aspect may be the battery monitoring device according to the fifth or sixth aspect, further comprising an integrated circuit, wherein the integrated circuit comprises a first current measurement unit that measures the current flowing through the first shunt resistor, a first voltage measurement unit that measures the voltage of each battery of the first assembled battery, a first impedance measurement calculation unit that calculates the AC impedance of each battery of the first assembled battery based on the current value measured by the first current measurement unit and the voltage value of each battery of the first assembled battery measured by the first voltage measurement unit, a second current measurement unit that measures the current flowing through the second shunt resistor, a second voltage measurement unit that measures the voltage of each battery of the second assembled battery, and a second impedance measurement calculation unit that calculates the AC impedance of each battery of the second assembled battery based on the current value measured by the second current measurement unit and the voltage value of each battery of the second assembled battery measured by the second voltage measurement unit.

[0031] This allows the battery monitoring device to be realized by a single integrated circuit having each function, thereby reducing the circuit scale compared to when multiple integrated circuits are used.

[0032] Furthermore, for example, a battery monitoring device according to an eighth aspect may be a battery monitoring device according to any one of the fifth to seventh aspects, in which the lowest battery of the first assembled battery and the highest battery of the second assembled battery are connected, the positive terminal of the highest battery of the first assembled battery is connected to the first shunt resistor, the first shunt resistor is connected to a first transistor which is the first switch, the negative terminal of the lowest battery of the second assembled battery is connected to the second shunt resistor, and the second shunt resistor is connected to a second transistor which is the second switch.

[0033] As a result, a transistor is disposed in each of the first measurement circuit and the second measurement circuit, and therefore it is possible to easily share some of the harnesses of the first measurement circuit and the second measurement circuit.

[0034] Furthermore, for example, a battery monitoring device according to a ninth aspect may be a battery monitoring device according to any one of the first to eighth aspects, and the plurality of batteries may include one or more batteries included in both the first assembled battery and the second assembled battery.

[0035] This makes it easier to detect faults in the measuring circuit by having one or more batteries provided in common.

[0036] Furthermore, for example, a battery monitoring device according to a tenth aspect may be the battery monitoring device according to any one of the first to ninth aspects, in which the lowest battery of the first assembled battery and the highest battery of the second assembled battery are connected, and the battery monitoring device may include a calculation unit that performs at least one of determining a failure of the first measurement circuit and the second measurement circuit based on the AC impedance of the lowest battery of the first assembled battery and the AC impedance of the highest battery of the second assembled battery, and calibrating the measured AC impedance of each of the plurality of batteries.

[0037] This allows for the detection of a fault in the measurement circuit using AC impedance as a parameter, thereby improving the safety of the battery monitoring device.

[0038] Furthermore, for example, a battery monitoring device according to an eleventh aspect may be the battery monitoring device according to any one of the first to tenth aspects, and may include a first calculation unit that estimates a first SOH of a first battery based on the AC impedance of an arbitrary first battery included in the first assembled battery, and that estimates a second SOH of a second battery based on the AC impedance of an arbitrary second battery included in the second assembled battery, and a second calculation unit that performs at least one of determining a failure of the first measurement circuit and the second measurement circuit based on a third SOH of the first battery and a fourth SOH of the second battery estimated from a parameter other than the AC impedance, and the first SOH and the second SOH, and calibrating the measured AC impedance of each of the plurality of batteries.

[0039] This makes it possible to detect a failure in the measurement circuit using SOH (State of Health: capacity maintenance rate) as a parameter, thereby improving the safety of the battery monitoring device.

[0040] Furthermore, for example, a battery monitoring device according to a twelfth aspect may be the battery monitoring device according to any one of the first to eleventh aspects, in which the lowest battery of the first assembled battery and the highest battery of the second assembled battery are connected, and may include a temperature measurement unit that measures the temperatures of the lowest battery and the highest battery based on the outputs of a first temperature sensor for measuring the temperature of the lowest battery of the first assembled battery and a second temperature sensor for measuring the temperature of the highest battery of the second assembled battery, and a battery state calculation unit that performs at least one of determining a failure of the first measurement circuit and the second measurement circuit based on the internal temperature of the lowest battery estimated from the AC impedance of the lowest battery of the first assembled battery and the temperatures of the highest battery and the lowest battery measured by the temperature measurement unit, and calibrating the measured AC impedance of each of the plurality of batteries.

[0041] This allows for the detection of a failure in the measurement circuit using the temperature as a parameter, thereby improving the safety of the battery monitoring device.

[0042] Furthermore, a battery monitoring method according to a thirteenth aspect generates a control signal to control a first measurement circuit to which the first assembled battery is connected, and a second measurement circuit to which the second assembled battery is connected, of a first assembled battery and a second assembled battery obtained by dividing a plurality of batteries connected in series, and calculates the AC impedance of each of the plurality of batteries based on a first current value flowing through the first measurement circuit and a voltage value of each battery included in the first assembled battery, and a second current value flowing through the second measurement circuit and a voltage value of each battery included in the second assembled battery, which are measured at different times, the first measurement circuit having a first switch connected in series with the first assembled battery, and the second measurement circuit having a second switch connected in series with the second assembled battery, and the control signal is generated to exclusively turn on the first switch and the second switch.

[0043] This provides the same effects as the battery monitoring device described above.

[0044] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0045] 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 each of the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in each of the following embodiments, components not recited in an independent claim are described as optional components.

[0046] In addition, the drawings are not necessarily strict illustrations, and the same reference numerals are used to designate substantially the same components in the drawings, and redundant explanations are omitted or simplified.

[0047] Furthermore, "connection" means an electrical connection, and includes not only a case where two circuit elements are directly connected, but also a case where two circuit elements are indirectly connected with another circuit element inserted between them.

[0048] Furthermore, in this specification, terms indicating relationships between elements such as "same," as well as numerical values ​​and numerical ranges, are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about several percent (or about 10%).

[0049] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0050] (First Embodiment) A battery monitoring device according to this embodiment will be described below with reference to Figures 1 and 2. Figure 1 is a diagram showing the configuration of a battery monitoring system 301 according to this embodiment.

[0051] 1 , the battery monitoring system 301 is a system for monitoring (or controlling) an assembled battery in which secondary batteries such as lithium ion batteries are connected in series. In this embodiment, the battery monitoring system 301 is a system for monitoring a first assembled battery 1 and a second assembled battery 2.

[0052] The battery monitoring system 301 includes a battery monitoring device 201 having a first load resistor 3, a first transistor 5, and a first shunt resistor 7 connected in series with the first assembled battery 1, a second load resistor 4, a second transistor 6, and a second shunt resistor 8 connected in series with the second assembled battery 2, a first thermistor 19, a second thermistor 20, and an integrated circuit 101. The battery monitoring system 301 may further include assembled batteries (the first assembled battery 1 and the second assembled battery 2) to be monitored.

[0053] In this embodiment, the battery pack is configured by connecting 18 batteries, batteries 1a to 1i and batteries 2a to 2i, in series. The first battery pack 1 includes one or more batteries, and in the example of FIG. 1, it includes nine batteries 1a to 1i connected in series, and the second battery pack 2 includes one or more batteries, and in the example of FIG. 1, it includes nine batteries 2a to 2i connected in series. The first battery pack 1 and the second battery pack 2 are connected in series to form one battery pack. Each of the batteries 1a to 1i and batteries 2a to 2i is a rechargeable secondary battery, such as a lithium-ion battery.

[0054] There is no particular limitation on the number of batteries included in each of the first assembled battery 1 and the second assembled battery 2, and for example, they may be different numbers. There is also no particular limitation on the number of batteries included in the battery monitoring system 301, as long as it is two or more. Hereinafter, batteries 1a to 1i and batteries 2a to 2i may also be referred to as cells.

[0055] As will be described in detail later, the battery monitoring system 301 is configured to measure the voltage and current of the first assembled battery 1 and the second assembled battery 2 in a time-sharing manner.

[0056] The first measuring circuit 1z is a circuit for measuring the AC impedance of each battery in the first assembled battery 1, and has a first load resistor 3, a first transistor 5, and a first shunt resistor 7 connected in series with the first assembled battery 1. When the first transistor 5 is turned ON, a loop circuit is formed by the first load resistor 3, the first transistor 5, the first shunt resistor 7, and the first assembled battery 1.

[0057] The first load resistor 3 is connected to the negative terminal of the first assembled battery 1 (the negative voltage terminal of the battery 1 i ) and is a resistor for passing a current for measuring the impedance of each battery of the first assembled battery 1 .

[0058] The first shunt resistor 7 is connected to the positive terminal of the first assembled battery 1 (the positive voltage terminal of battery 1a), and is a current measurement resistor for measuring the current flowing through the first measurement circuit 1z including the first assembled battery 1, with both ends connected to the first current measurement unit 9. Specifically, the first shunt resistor 7 is a resistor for measuring the current (pulse current) discharged from the first assembled battery 1 when the first transistor 5 is turned on.

[0059] The first transistor 5 is connected between the first load resistor 3 and the first shunt resistor 7, and is switched ON and OFF by a control signal generated by the first current drive waveform generator 11. The first transistor 5 is controlled by the control signal so as to switch at a frequency at which the impedance is measured. The first transistor 5 is a p-type transistor, but is not limited to this. The first transistor 5 is an example of a switch (first switch).

[0060] In the first measurement circuit 1z configured in this manner, heat is generated in the first load resistor 3 by the total voltage of only the batteries 1a to 1i out of the batteries 1a to 1i and 2a to 2i. Because the voltage applied to the first load resistor 3 can be made lower than in the case of Figure 6, the heat generated in the first load resistor 3 can be reduced.

[0061] The arrangement order of the first load resistor 3, the first transistor 5, and the first shunt resistor 7 is not limited to the order shown in FIG. 1 , and they may be connected in series between the positive terminal of the first assembled battery 1 and the negative terminal of the first assembled battery 1.

[0062] The second measurement circuit 2z is a circuit for measuring the AC impedance of each battery in the second assembled battery 2, and has a second load resistor 4, a second transistor 6, and a second shunt resistor 8 connected in series with the second assembled battery 2. When the second transistor 6 is turned ON, a loop circuit is formed by the second load resistor 4, the second transistor 6, the second shunt resistor 8, and the second assembled battery 2.

[0063] The second load resistor 4 is connected to the positive terminal of the second assembled battery 2 (positive voltage terminal of the battery 2 a ) and is a resistor for passing a current for measuring the impedance of each battery of the second assembled battery 2 .

[0064] The second shunt resistor 8 is connected to the negative terminal of the second assembled battery 2 (the negative voltage terminal of battery 2i), and is a current measurement resistor for measuring the current flowing through the second measurement circuit 2z including the second assembled battery 2, with both ends connected to the second current measurement unit 10. Specifically, the second shunt resistor 8 is a resistor for measuring the current (pulse current) discharged from the second assembled battery 2 when the second transistor 6 is turned on.

[0065] The second transistor 6 is connected between the second load resistor 4 and the second shunt resistor 8, and is switched ON and OFF by a control signal generated by the second current drive waveform generator 12. The second transistor 6 is controlled by the control signal so as to switch at a frequency at which the impedance is measured. The second transistor 6 is an n-type transistor, but is not limited to this. The second transistor 6 is an example of a switch (second switch).

[0066] In the second measurement circuit 2z configured in this manner, heat is generated in the second load resistor 4 by the total voltage of only batteries 2a to 2i out of batteries 1a to 1i and 2a to 2i. Because the voltage applied to the second load resistor 4 can be lowered compared to the case of Figure 6, the heat generated in the second load resistor 4 can be reduced.

[0067] The arrangement order of the second load resistor 4, the second transistor 6, and the second shunt resistor 8 is not limited to the order shown in FIG. 1 , and they may be connected in series between the positive terminal of the second assembled battery 2 and the negative terminal of the second assembled battery 2.

[0068] The first switch and the second switch are not limited to being semiconductor switches, and may be switches other than semiconductor switches.

[0069] Here, the first measurement circuit 1z and the second measurement circuit 2z share a portion of the wiring (e.g., a portion of the harness). The battery monitoring system 301 includes a common harness 30 shared by the first measurement circuit 1z and the second measurement circuit 2z. The common harness 30 is arranged to connect the negative terminal of the first assembled battery 1 and the positive terminal of the second assembled battery 2 to the first load resistor 3 and the second load resistor 4. This makes it possible to reduce the size of the measurement circuit for a battery pack including multiple batteries using a single integrated circuit 101. Note that the provision of the common harness 30 is not essential, and the first measurement circuit 1z and the second measurement circuit 2z may be formed using different wiring.

[0070] The first thermistor 19 is disposed adjacent to the first assembled battery 1 and is a temperature sensor for measuring the temperature of the first assembled battery 1 (the ambient temperature of the first assembled battery 1) during the period when the impedance of the first assembled battery 1 is being measured. In this embodiment, the first thermistor 19 is disposed adjacent to the battery 1i (lowest cell) in the first assembled battery 1 that is closest to the second assembled battery 2, and measures the ambient temperature of that battery 1i. The first thermistor 19 may also be disposed at the voltage terminal of the lowest cell of the first assembled battery 1.

[0071] The second thermistor 20 is disposed adjacent to the second assembled battery 2 and is a temperature sensor for measuring the temperature of the second assembled battery 2 (the ambient temperature of the second assembled battery 2) during the period when the impedance of the second assembled battery 2 is being measured. In this embodiment, the second thermistor 20 is disposed adjacent to the battery 2a (top cell) in the second assembled battery 2 that is closest to the first assembled battery 1, and measures the ambient temperature of that battery 2a. The second thermistor 20 may also be disposed at the voltage terminal of the top cell of the second assembled battery 2.

[0072] Since batteries 1i and 2a are adjacent batteries, first thermistor 19 and second thermistor 20 are located close to each other. Therefore, if batteries 1i and 2a or the elements of first measuring circuit 1z and second measuring circuit 2z are normal, the temperature measured by first thermistor 19 and the temperature measured by second thermistor 20 are likely to be close to each other.

[0073] The temperature sensor provided in the battery monitoring system 301 is not limited to a thermistor, and may be a temperature sensor using other elements such as a thermocouple.

[0074] The integrated circuit 101 includes a first current measurement unit 9, a second current measurement unit 10, a first current drive waveform generation unit 11, a second current drive waveform generation unit 12, a voltage measurement unit 13, an SOC (State of Charge) calculation unit 14, an impedance calculation unit 15, a battery state calculation unit 16, a temperature measurement unit 17, and a storage unit 18. The integrated circuit 101 includes a processor, a memory, etc. The memory is a read-only memory (ROM) and a random access memory (RAM), etc., and can store programs executed by the processor. The first current measurement unit 9, the second current measurement unit 10, the first current drive waveform generation unit 11, the second current drive waveform generation unit 12, the voltage measurement unit 13, the SOC calculation unit 14, the impedance calculation unit 15, the battery state calculation unit 16, and the temperature measurement unit 17 are realized by a processor or the like that executes a program stored in a memory. Also, for example, each of the above functions is realized by one integrated circuit 101.

[0075] The first current measurement unit 9 measures the current flowing in a first measurement circuit 1z including the first assembled battery 1. The first current measurement unit 9 may include an ADC (Analog-Digital Converter) unit that converts an analog signal value corresponding to the current of the first assembled battery 1 into a digital signal value, and a calculation unit that calculates a current value by arithmetic processing of the digital signal value that is the output of the ADC unit. Note that the first current measurement unit 9 is a resistance detection type current sensor that uses the first shunt resistor 7, but it may also be a magnetic field detection type current sensor.

[0076] The second current measurement unit 10 measures the current flowing in a second measurement circuit 2z including the second assembled battery 2. The second current measurement unit 10 may include an ADC unit that converts an analog signal value corresponding to the current of the second assembled battery 2 into a digital signal value, and a calculation unit that calculates the current value by arithmetic processing of the digital signal value that is the output of the ADC unit. Note that the second current measurement unit 10 is a resistance detection type current sensor that uses the second shunt resistor 8, but may also be a magnetic field detection type current sensor.

[0077] The first current drive waveform generating unit 11 generates a control signal for controlling ON / OFF of the first transistor 5 and outputs it to the first transistor 5. The control signal is, for example, a rectangular wave signal that can be controlled to have an arbitrary period, and is input to the gate electrode of the first transistor 5. Furthermore, the control signal is a control signal having a plurality of frequency components.

[0078] The second current drive waveform generating unit 12 generates a control signal for controlling ON / OFF of the second transistor 6 and outputs it to the second transistor 6. The control signal is, for example, a rectangular wave signal that can be controlled to an arbitrary period, and is input to the gate electrode of the second transistor 6. The control signal is also a control signal having multiple frequency components. The multiple frequency components here may be, for example, the same frequency components as the multiple frequency components of the control signal generated by the first current drive waveform generating unit 11.

[0079] The first current drive waveform generating unit 11 and the second current drive waveform generating unit 12 generate control signals so that only one of the first transistor 5 and the second transistor 6 is turned ON. The control signals are signals for operating the first transistor 5 and the second transistor 6 in a time-division manner within independent periods. It can also be said that the first current drive waveform generating unit 11 and the second current drive waveform generating unit 12 generate control signals for exclusively turning on the first transistor 5 and the second transistor 6. In this way, the control signals control the period in which the first transistor 5 is turned ON and the period in which the second transistor 6 is turned ON so that they do not overlap in time.

[0080] This allows the current and voltage of the first assembled battery 1 and the current and voltage of the second assembled battery 2 to be measured in different time periods in a time-division manner. Therefore, by controlling the ON and OFF of the first transistor 5 and the second transistor 6 in a time-division manner, the timing of impedance measurements of the first assembled battery 1 and the second assembled battery 2 can be made independent (different), and as a result, the heat generation time is dispersed, making it possible to suppress heat generation in the load resistor. Note that the first current drive waveform generator 11 and the second current drive waveform generator 12 are examples of signal generators.

[0081] The period in which the first transistor 5 is ON and the period in which the second transistor 6 is ON are not limited to being completely non-overlapping in time, and the ON periods may only partially overlap.

[0082] 2 is a diagram showing the voltage waveforms of the control signal pulses applied to the transistor according to this embodiment, illustrating the voltage waveforms of four control signals (control signals w1 to w4) generated by the first current drive waveform generator 11 and the second current drive waveform generator 12.

[0083] The control signal w1 has a frequency of 2f and a voltage waveform with a duty ratio of 50%.

[0084] The control signal w2 has a frequency f and shows a voltage waveform when the duty ratio is 50%.

[0085] When the first transistor 5 is turned on by the control signal w1, a pulse current with a frequency of 2f is discharged from the first assembled battery 1 during the on period, generating heat in the first load resistor 3. When the control signal is switched from the control signal w1 to the control signal w2, that is, when the frequency of the control signal is changed from 2f to f and the duty ratio is maintained at 50%, the amount of heat generated by the first load resistor 3 doubles.

[0086] To prevent differences in heat generation due to differences in the frequency of the control signal, it is preferable to adjust the duty ratio according to the frequency. This allows the heat generation amount to approach a constant value while maintaining a constant ON period, even when the frequency of the control signal is changed. For example, when changing the frequency of the control signal from 2f to f, it is preferable to use the control signal w3, which has a duty ratio changed from 50% to 25%. Furthermore, to further reduce the heat generation amount, it is also possible to use the control signal w4, which has a duty ratio of 50% within the pulse of the ON period.

[0087] The first current drive waveform generating unit 11 sets the duty ratio of the first control signal according to the period of the first control signal, and the second current drive waveform generating unit 12 sets the duty ratio of the second control signal according to the period of the second control signal. The first current drive waveform generating unit 11 and the second current drive waveform generating unit 12 set the duty ratio of the control signal having a frequency of from f to 2f so that the difference between the amount of heat generated at a reference frequency set in a predetermined frequency band (e.g., from f to 2f) and the amount of heat generated at other frequencies from f to 2f is equal to or less than a predetermined value. The first current drive waveform generating unit 11 and the second current drive waveform generating unit 12 may, for example, set the duty ratio to be smaller as the frequency decreases and larger as the frequency increases. For example, a table correlating frequencies with duty ratios may be stored in the storage unit 18, and the first current drive waveform generating unit 11 and the second current drive waveform generating unit 12 may switch the duty ratio for each frequency using the table.

[0088] The reference frequency may be a frequency that is higher than a predetermined frequency (e.g., the highest) within the frequency band. If the frequency band is equal to or higher than frequency f and equal to or lower than frequency 2f, the reference frequency may be frequency 2f. For example, the reference frequency may be a frequency at which the amount of heat generated is equal to or lower than a predetermined value (e.g., the smallest) when the duty ratio is the same within the frequency band.

[0089] For example, during the period in which a control signal is applied to the first transistor 5, a control signal (a control signal of a constant voltage) that turns the second transistor 6 OFF may be applied.

[0090] 1 , a voltage measurement unit 13 is provided for each battery, and measures the voltage of the connected battery. The voltage measurement unit 13 may include an ADC unit that converts an analog signal value corresponding to the battery voltage into a digital signal value, and a calculation unit that processes the digital signal value output from the ADC unit to calculate a voltage value.

[0091] The SOC calculation unit 14 measures the SOC of the battery pack. For example, the SOC calculation unit 14 may acquire the current and voltage of the battery pack or of each of the batteries 1a to 2i that make up the battery pack, and calculate the SOC by a coulomb counting method or estimation from an SOC-OCV (Open Circuit Voltage) curve.

[0092] The impedance calculation unit 15 calculates the AC impedance of each of the plurality of batteries 1a-1i and 2a-2i from the AC voltage and AC current obtained by measuring the first assembled battery 1 and the second assembled battery 2. The impedance calculation unit 15 measures the current I1 flowing through the first shunt resistor 7 and the voltage Vn1 of each battery of the first assembled battery 1, which are obtained by applying a control signal having multiple frequency components to the control terminal of the first transistor 5. The impedance calculation unit 15 also measures the current I2 flowing through the second shunt resistor 8 and the voltage Vn2 of each battery of the second assembled battery 2, which are obtained by applying a control signal having multiple frequency components to the control terminal of the second transistor 6.

[0093] The impedance calculation unit 15 then converts the measured currents I1 and I2 into complex currents and the measured voltages Vn1 and Vn2 into complex voltages. The impedance calculation unit 15 then averages the complex currents and the complex voltages. The impedance calculation unit 15 calculates the AC impedance of each battery by dividing the averaged complex voltage by the averaged complex current. Each AC impedance is a complex number (complex impedance) and has a real component Re and an imaginary component Im. Hereinafter, AC impedance may also be simply referred to as impedance.

[0094] The battery state calculation unit 16 estimates at least one of the SOH (State of Health: capacity maintenance rate) and the internal temperature, which indicate the deterioration state of the battery, from the calculation result of the impedance calculation unit 15 .

[0095] When a first correspondence relationship between AC impedance and full charge capacity of the battery is acquired in advance, the battery state calculation unit 16 may estimate the current full charge capacity of the battery from the first correspondence relationship and the current AC impedance, and calculate the SOH (%) by dividing the estimated current full charge capacity by the initial full charge capacity and multiplying the result by 100. The initial full charge capacity and the first correspondence relationship may be stored in the storage unit 18. Furthermore, the first correspondence relationship may be, for example, a table in which AC impedance and full charge capacity of the battery are associated with each other.

[0096] When a second correspondence relationship between AC impedance and internal temperature of the battery is acquired in advance, the battery state calculation unit 16 may estimate the current internal temperature of the battery from the second correspondence relationship and the current AC impedance. The second correspondence relationship may be stored in the storage unit 18. Furthermore, the second correspondence relationship may be, for example, a table in which AC impedance and internal temperature of the battery are associated with each other.

[0097] The method for estimating the SOH and the internal temperature is not limited to the above, and any known method may be used.

[0098] The temperature measurement unit 17 measures the temperature of the battery pack. The temperature measurement unit 17 is connected to a first thermistor 19 located close to the first battery pack 1 and a second thermistor 20 located close to the second battery pack 2, and measures the temperatures around the first thermistor 19 and the second thermistor 20. In this embodiment, the temperature measurement unit 17 measures the temperatures near the battery 1i and the battery 2a.

[0099] The storage unit 18 is a storage device that stores various information and various programs for estimating the battery state, and is realized by, for example, a hard disk drive (HDD) or a semiconductor memory.

[0100] The integrated circuit 101 may include a diagnostic calibration unit (for example, a diagnostic calibration unit 21 shown in FIG. 3, which will be described later) that performs fault diagnosis and impedance calibration.

[0101] (Embodiment 2) The configuration of a battery monitoring device according to this embodiment will be described with reference to FIG. 3. FIG. 3 is a diagram showing the configuration of a battery monitoring system 301 according to this embodiment. The battery monitoring system 301 according to this embodiment differs from the battery monitoring system 301 according to Embodiment 1 mainly in that the load resistor (third load resistor 22) is a resistor common to the first measurement circuit 1z and the second measurement circuit 2z. Note that the following description will focus on the differences from Embodiment 1, and descriptions of content that is the same as or similar to Embodiment 1 will be omitted or simplified. For convenience, components that are the same as or similar to those in Embodiment 1 will be described using the reference numerals of Embodiment 1.

[0102] As shown in FIG. 3, a battery monitoring system 301 includes a third load resistor 22 in place of the first load resistor 3 and the second load resistor 4 shown in FIG.

[0103] The third load resistor 22 is provided in the common harness 30. One end of the third load resistor 22 is connected to the negative terminal of the first assembled battery 1 and the positive terminal of the second assembled battery 2, and the other end is connected to the first transistor 5 and the second transistor 6. This allows the number of load resistors to be reduced, and therefore the size of the measurement circuit to be reduced.

[0104] The diagnostic calibration unit 21 diagnoses (determines) whether or not the measurement circuit (e.g., an element of the measurement circuit) is faulty based on the AC impedance, and also calibrates the impedance. The diagnostic calibration unit 21 will be described later with reference to FIG. 5.

[0105] The number of batteries included in the first assembled battery 1 and the number of batteries included in the second assembled battery 2 are the same, but may be different as long as the measurement accuracy is within a range that satisfies the desired accuracy.

[0106] (Embodiment 3) The configuration of a battery monitoring device according to this embodiment will be described with reference to FIG. 4. FIG. 4 is a diagram showing the configuration of a battery monitoring system 301 according to this embodiment. The battery monitoring system 301 according to this embodiment differs from the battery monitoring system 301 according to Embodiment 1 in that a battery 12a is included in each of the first assembled battery 1 and the second assembled battery 2. Note that the following description will focus on the differences from Embodiment 1, and descriptions of content that is the same as or similar to Embodiment 1 will be omitted or simplified. For convenience, components that are the same as or similar to those in Embodiment 1 will be described using the reference numerals of Embodiment 1.

[0107] 4 , in the battery monitoring system 301 according to this embodiment, a first load resistor 3 is connected to the negative terminal of the lowest cell of the first assembled battery 1 and a second load resistor 4 is connected to the positive terminal of the highest cell of the second assembled battery 2, so that the lowest cell of the first assembled battery 1 and the highest cell of the second assembled battery 2 are the same cell. The first assembled battery 1 includes nine batteries, including battery 12a, which is common to batteries 1a to 1h, and the second assembled battery 2 includes ten batteries, including battery 12a, which is common to batteries 2a to 2i. Note that the number of batteries is not limited to this; for example, the first assembled battery 1 and the second assembled battery 2 may have the same number of batteries.

[0108] The voltage of battery 12a is measured when measurement is performed for first assembled battery 1 and when measurement is performed for second assembled battery 2. The voltage measurement result (voltage value) of battery 12a when measurement is performed for first assembled battery 1 and the voltage measurement result (voltage value) of battery 12a when measurement is performed for second assembled battery 2 should be the same voltage value, and if the two voltage values ​​are different, it can be determined whether any element of the measurement circuit (e.g., at least one of first load resistor 3, second load resistor 4, first transistor 5, second transistor 6, first shunt resistor 7, and second shunt resistor 8) has failed. In other words, the battery monitoring system 301 according to this embodiment can perform failure diagnosis of the measurement circuit.

[0109] This determination may be made using, for example, the current and past voltage values ​​of the batteries 12a in the first assembled battery 1 or the second assembled battery 2. In other words, it may be possible to determine whether the batteries 12a have deteriorated over time.

[0110] The first thermistor 19 is disposed near the battery 12a which is included in common.

[0111] The number of batteries included in common in the first assembled battery 1 and the second assembled battery 2 is not limited to one, but may be multiple.

[0112] (Operation Example) Next, the operation related to the fault diagnosis and calibration performed by the battery monitoring system 301 described in each of the above embodiments will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the operation related to the fault diagnosis and calibration (battery monitoring method) in the battery monitoring system 301 according to each of the embodiments.

[0113] As shown in FIG. 5 , first, the battery monitoring device 201 controls the lower-level EIS (Electro-chemical Impedance Spectroscopy) measurement circuit (second measurement circuit 2z) to measure the AC voltage and AC current of the lower-level assembled battery group (second assembled battery 2) and also measure the second thermistor temperature (S1). The second thermistor temperature is a temperature measured using the second thermistor 20. The battery monitoring device 201 measures the AC voltage and AC current of the second assembled battery 2 by turning off the first transistor 5 and turning on the second transistor 6. Turning on the second transistor 6 means switching the second transistor 6 at a frequency at which the impedance is measured using a control signal such as that shown in FIG. 2 .

[0114] Next, after step S1, the battery monitoring device 201 controls the upper EIS measurement circuit (first measurement circuit 1z) to measure the AC voltage and AC current of the upper assembled battery group (first assembled battery 1), and also measures the first thermistor temperature (S2). The first thermistor temperature is a temperature measured using the first thermistor 19. The battery monitoring device 201 measures the AC voltage and AC current of the first assembled battery 1 by turning on the first transistor 5 and turning off the second transistor 6.

[0115] In this way, the measurements of the first measurement circuit 1z and the second measurement circuit 2z are performed at different timings in a time-division manner.

[0116] Next, the impedance calculation unit 15 calculates the measured AC voltage and AC current into impedance (AC impedance) (S3).

[0117] Next, the battery state calculation unit 16 estimates the first SOH and the internal temperature from the impedance calculated by the impedance calculation unit 15 (S4).

[0118] Next, battery state calculation unit 16 stores the measurement results and estimation results in storage unit 18 (S5). As a result, storage unit 18 stores the measured values ​​measured in steps S1 and S2 and the estimated values ​​estimated in step S4.

[0119] Next, the battery state calculation unit 16 estimates the second SOH using the time-sampled current data and voltage data (S6). The battery state calculation unit 16 estimates the second SOH based on the time responses of the current and voltage when the battery is discharged under a constant frequency condition.

[0120] In the time sampling, the voltage of each battery of the first assembled battery 1 and the second assembled battery 2 is sampled by the voltage measuring unit 13, the current is sampled by the first current measuring unit 9, and the current is sampled by the second current measuring unit 10. Furthermore, the measurements (time sampling) of the first measuring circuit 1z and the second measuring circuit 2z may be performed at different timings in a time-division manner.

[0121] Next, the battery state calculation unit 16 determines whether the difference between values ​​(e.g., estimated values) related to adjacent or shared cells is equal to or less than a threshold (S7). The value related to adjacent or shared cells may be the measured impedance itself, or may be a value indicating the battery state such as SOH or internal temperature. An example in which the value indicates the battery state will be described below.

[0122] 1 or 3, the battery state calculation unit 16 determines whether the difference in SOH or internal temperature between adjacent batteries (e.g., batteries 1i and 2a) is equal to or less than a threshold. When the SOH is used, the battery state calculation unit 16 performs at least one of the following: comparing the first SOH of battery 1i estimated in step S4 with the first SOH of battery 2a; and comparing the second SOH of battery 1i estimated in step S6 with the second SOH of battery 2a, and determines whether the difference in SOH is equal to or less than a threshold.

[0123] 4, the battery state calculation unit 16 determines whether the difference in SOH or internal temperature of a common cell (e.g., battery 12a) is equal to or less than a threshold value. When the SOH is used, the battery state calculation unit 16 performs at least one of the following: comparing a first SOH of battery 12a at the time of measurement by first measurement circuit 1z with the first SOH of battery 12a at the time of measurement by second measurement circuit 2z; or comparing a second SOH of battery 12a at the time of measurement by first measurement circuit 1z with the second SOH of battery 12a at the time of measurement by second measurement circuit 2z; and determining whether the difference in SOH is equal to or less than a threshold value.

[0124] If any of the elements included in the first measurement circuit 1z and the second measurement circuit 2z is faulty, the difference in step S7 will be greater than the threshold value. At this point, it is possible to determine whether or not there is a fault, but if there is a fault, it is not possible to identify which of the measurement circuits has an element that is faulty. The threshold value is set in advance and stored in the memory unit 18.

[0125] The determination in step S7 may be made based on, for example, whether the difference between the first SOH of the battery (for example, battery 1i in the first measurement circuit 1z) estimated in step S4 and the second SOH of the battery estimated in step S6 is equal to or less than a threshold value. In this case, the determination is made in each of the first measurement circuit 1z and the second measurement circuit 2z.

[0126] Next, if the difference between the values ​​is not equal to or less than the threshold, that is, if the difference between the two estimated values ​​is greater than the threshold (No in S7), there is a possibility that one of the elements in the measurement circuit is faulty, so the diagnostic calibration unit 21 reads the reference value of the value from the storage unit 18 and compares it to identify the faulty circuit (S8). To identify which of the elements in the first measurement circuit 1z and the second measurement circuit 2z is faulty, the diagnostic calibration unit 21 reads the reference value of SOH, which is an example of a value, from the storage unit 18, and based on the reference value and the SOH of the adjacent battery, identifies, for example, the measurement circuit including the battery with the larger difference from the reference value as the faulty circuit.

[0127] Next, the diagnostic and calibration unit 21 issues a fault notification (S9).The diagnostic and calibration unit 21 transmits information indicating the identified faulty circuit to a terminal device of a user (for example, a manager of the battery pack).

[0128] Furthermore, if the difference between the values ​​is equal to or less than the threshold, i.e., if the difference between the two estimated values ​​is close (Yes in S7), the diagnostic calibration unit 21 further determines whether or not the two measurement circuits have a common cell configuration (S10). A common cell configuration means a configuration in which the two measurement circuits have a common cell (battery 12a), as shown in FIG. 4. Information indicating whether or not the two measurement circuits have a common cell configuration may be stored in, for example, the storage unit 18. Note that if the difference between the values ​​is equal to or less than the threshold, it means that the measurement circuit is not faulty.

[0129] Next, if the diagnostic calibration unit 21 determines that the common cell configuration is present (Yes in S10), it further reads a reference value from the storage unit 18 and compares it to determine whether it is equal to or less than a threshold value (S11). The diagnostic calibration unit 21 compares the SOH or internal temperature of the common cell (battery 12a in the example of FIG. 4) with the reference value and determines whether the difference is equal to or less than a threshold value. The threshold value here may be the same as the threshold value in step S7, or may be different from the threshold value in step S7.

[0130] If the diagnostic calibration unit 21 determines that the difference is equal to or smaller than the threshold value in a common cell configuration (Yes in S11), or if it determines that the common cell configuration is not present (No in S10), the process ends.

[0131] Furthermore, if the diagnostic calibration unit 21 determines that the difference is not equal to or less than the threshold value in the common cell configuration, that is, if the difference between the estimated value and the reference value is greater than the threshold value (No in S11), the diagnostic calibration unit 21 calibrates the impedance calculation based on the reference value (S12). The diagnostic calibration unit 21 determines that the impedance measurement accuracy has decreased due to an external factor (e.g., the influence of a magnetic field from an external circuit), and calibrates the impedance calculated in step S3. Calibration here means bringing the impedance calculated in step S3 closer to the true value based on the reference value.

[0132] The diagnostic calibration unit 21 calibrates the impedance stored in the storage unit 18 based on the reference value, and stores the calibrated impedance in the storage unit 18. The diagnostic calibration unit 21 may replace the impedance calculated in step S3 with the reference value, or may replace it with a statistical value of impedances acquired in multiple past measurements, or may multiply the impedance calculated in step S3 by a coefficient based on the reference value. The statistical value is an average value, but may also be, for example, a median.

[0133] While the battery monitoring device according to one or more aspects has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as it does not deviate from the spirit of the present disclosure, various modifications conceivable by a person skilled in the art to the present embodiments and configurations constructed by combining components of different embodiments may also be included in the present disclosure.

[0134] For example, the battery monitoring device 201 and battery monitoring system 301 according to the present disclosure can be used as a battery monitoring device and BMS that monitor batteries such as assembled batteries in which cells such as lithium-ion batteries are connected in series. In particular, the battery monitoring device 201 and battery monitoring system 301 can be used as a small battery monitoring device that can measure the impedance of a battery, for example, a battery monitoring device that monitors environmentally friendly vehicles such as electric vehicles, storage batteries for a stable supply of renewable energy, and the like.

[0135] In addition, in each of the above embodiments, an example in which a plurality of batteries are divided into two assembled batteries has been described, but the number of divisions is not limited to two and may be three or more. In this case, the impedance measurements are performed on each of the three or more assembled batteries at different times.

[0136] In each of the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may 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.

[0137] The order in which the steps in the flowchart are executed is merely an example for specifically explaining the present disclosure, and other orders may be used. Some of the steps may be executed simultaneously (in parallel) with other steps, or some of the steps may not be executed.

[0138] The division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as a single functional block, one functional block may be divided into multiple blocks, or some functions may be moved to another functional block.Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0139] Furthermore, the battery monitoring device 201 according to each of the above embodiments may be realized as a single device or may be realized by multiple devices. When the battery monitoring device 201 is realized by multiple devices, the components of the battery monitoring device 201 may be distributed in any manner among the multiple devices. When the battery monitoring device 201 is realized by multiple devices, the communication method between the multiple devices is not particularly limited, and may be wireless communication or wired communication. Furthermore, wireless communication and wired communication may be combined between the devices.

[0140] Furthermore, each component described in each of the above embodiments may be implemented as software or, typically, as an LSI, which is an integrated circuit. These components may be individually integrated into a single chip, or some or all of them may be integrated into a single chip. While the term "LSI" is used here, it may also be referred to as an IC, system LSI, super LSI, or ultra LSI depending on the level of integration. Furthermore, the integrated circuit implementation is not limited to LSIs; it may also be implemented using dedicated circuits (general-purpose circuits that execute dedicated programs) or general-purpose processors. It is also possible to use FPGAs (Field Programmable Gate Arrays), which can be programmed after LSI fabrication, or reconfigurable processors, which allow the connection or settings of circuit cells within an LSI to be reconfigured. Furthermore, if an integrated circuit technology that replaces LSIs emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology may be used to integrate the components.

[0141] A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple processing units on a single chip, and is specifically a computer system comprising a microprocessor, ROM, RAM, etc. The ROM stores computer programs. The system LSI achieves its functions when the microprocessor operates in accordance with the computer programs.

[0142] Furthermore, one aspect of the present disclosure may be a computer program that causes a computer to execute each of the characteristic steps included in the battery monitoring method shown in FIG. 5 .

[0143] Furthermore, for example, the program may be a program to be executed by a computer. Another aspect of the present disclosure may be a computer-readable non-transitory recording medium on which such a program is recorded. For example, such a program may be recorded on a recording medium and distributed or circulated. For example, the distributed program may be installed in a device having another processor, and the program may be executed by the processor, thereby causing the device to perform each of the above processes.

[0144] The present disclosure is useful for a battery monitoring device that monitors batteries such as a battery pack.

[0145] 1 First assembled battery 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 12a Battery 1z First measurement circuit 2 Second assembled battery 2z Second measurement circuit 3 First load resistor 4 Second load resistor 5 First transistor 6 Second transistor 7 First shunt resistor 8 Second shunt resistor 9 First current measurement unit 10 Second current measurement unit 11 First current drive waveform generation unit 12 Second current drive waveform generation unit 13 Voltage measurement unit 14 SOC calculation unit 15 Impedance calculation unit 16 Battery state calculation unit 17 Temperature measurement unit 18 Memory unit 19 First thermistor (first temperature sensor) 20 Second thermistor (second temperature sensor) 21 Diagnostic calibration unit 22 Third load resistor 30 Common harness 101 Integrated circuit 201 Battery monitoring device 301 Battery monitoring system 901, 902, 903 Impedance measurement integrated circuits w1, w2, w3, w4 Control signal

Claims

1. A signal generation unit that generates control signals to control a first measurement circuit to which a first set of batteries is connected, and a second measurement circuit to which a second set of batteries is connected, which are obtained by dividing a plurality of batteries connected in series into a first set and a second set of batteries, The system includes an impedance calculation unit that calculates the AC impedance of each of the plurality of batteries based on the measured first current value flowing through the first measurement circuit and the voltage value of each battery included in the first battery set, and the second current value flowing through the second measurement circuit and the voltage value of each battery included in the second battery set. The first measuring circuit has a first switch connected in series with the first battery set, The second measuring circuit has a second switch connected in series with the second battery pack, The signal generation unit generates the control signals for turning on the first switch and the second switch. Battery monitoring device.

2. The first measuring circuit has a first transistor connected to the first battery pack as the first switch, The second measuring circuit has a second transistor connected to the second battery pack as the second switch, The control signal is a signal for operating the first transistor and the second transistor in a time-division manner within independent periods. The battery monitoring device according to claim 1.

3. The first control signal output to the first transistor and the second control signal output to the second transistor are rectangular wave signals that can be controlled to any period. The signal generation unit sets the duty cycle of the first control signal according to the period of the first control signal, and sets the duty cycle of the second control signal according to the period of the second control signal. The battery monitoring device according to claim 2.

4. The first measurement circuit and the second measurement circuit share some common wiring harnesses. The battery monitoring device according to claim 1.

5. The first measurement circuit has a first load resistor for measuring the AC impedance and a first shunt resistor for measuring the current, connected to the first battery set. The second measurement circuit has a second load resistor for measuring the AC impedance and a second shunt resistor for measuring the current, connected to the second battery set. The aforementioned common harness is arranged to connect the negative terminal of the first battery set and the positive terminal of the second battery set with the first load resistor and the second load resistor. The battery monitoring device according to claim 4.

6. The first measurement circuit comprises the first battery set, and a first load resistor connected to the first battery set for measuring the AC impedance and a first shunt resistor for measuring current. The second measurement circuit comprises the second battery set, and a second load resistor connected to the second battery set for measuring the AC impedance and a second shunt resistor for measuring current. The first load resistor and the second load resistor are provided in the common part of the harness. The battery monitoring device according to claim 4.

7. Furthermore, equipped with integrated circuits, The aforementioned integrated circuit is A first current measuring unit for measuring the current flowing through the first shunt resistor, A first voltage measuring unit for measuring the voltage of each cell in the first battery set, A first impedance measurement calculation unit calculates the AC impedance of each battery in the first battery set based on the current value measured by the first current measurement unit and the voltage value of each battery in the first battery set measured by the first voltage measurement unit. A second current measuring unit for measuring the current flowing through the second shunt resistor, A second voltage measuring unit for measuring the voltage of each battery in the second battery set, The system includes a second impedance measurement calculation unit that calculates the AC impedance of each battery in the second battery set based on the current value measured by the second current measurement unit and the voltage value of each battery in the second battery set measured by the second voltage measurement unit. The battery monitoring device according to claim 5 or 6.

8. The lowest cell in the first battery set and the highest cell in the second battery set are connected. The positive terminal of the uppermost battery in the first battery set is connected to the first shunt resistor. The first shunt resistor and the first transistor, which is the first switch, are connected. The negative terminal of the lowest cell in the second battery set is connected to the second shunt resistor. The second shunt resistor and the second transistor, which is the second switch, are connected. The battery monitoring device according to claim 5 or 6.

9. The plurality of batteries include one or more batteries that are included in both the first battery set and the second battery set. The battery monitoring device according to claim 1.

10. The lowest cell in the first battery set and the highest cell in the second battery set are connected. The system includes a calculation unit that determines a fault in the first measurement circuit and the second measurement circuit based on the AC impedance of the lowest cell in the first battery set and the AC impedance of the highest cell in the second battery set, and that performs at least one of the following: calibrating the AC impedance of each of the measured cells. A battery monitoring device according to any one of claims 1 to 6 or 9.

11. A first calculation unit estimates the first state of operating (SOH) of the first battery based on the AC impedance of any first battery included in the first battery set, and estimates the second state of operating (SOH) of the second battery based on the AC impedance of any second battery included in the second battery set. The system includes a second calculation unit that determines a fault in the first and second measurement circuits based on the third SOH of the first battery and the fourth SOH of the second battery estimated from parameters other than AC impedance, and the first and second SOH, and that performs at least one of the following: calibrating the measured AC impedance of each of the plurality of batteries. A battery monitoring device according to any one of claims 1 to 6 or 9.

12. The lowest cell in the first battery set and the highest cell in the second battery set are connected. A temperature measuring unit that measures the temperatures of the lowest and highest batteries based on the outputs of a first temperature sensor for measuring the temperature of the lowest battery in the first battery set and a second temperature sensor for measuring the temperature of the highest battery in the second battery set, The battery state calculation unit performs at least one of the following: determining a failure in the first measurement circuit and the second measurement circuit based on the internal temperature of the lowest battery of the first battery set estimated from the AC impedance of the lowest battery, and the temperatures of the highest and lowest batteries measured by the temperature measurement unit; and calibrating the measured AC impedance of each of the plurality of batteries. A battery monitoring device according to any one of claims 1 to 6 or 9.

13. Control signals are generated to control a first measurement circuit to which the first set of batteries is connected, and a second measurement circuit to which the second set of batteries is connected, which are obtained by dividing a set of batteries connected in series into a first set and a second set of batteries. Based on the measured first current value flowing through the first measurement circuit and the voltage value of each battery included in the first battery set, and the second current value flowing through the second measurement circuit and the voltage value of each battery included in the second battery set, the AC impedance of each of the plurality of batteries is calculated. The first measuring circuit has a first switch connected in series with the first battery set, The second measuring circuit has a second switch connected in series with the second battery pack, In generating the control signals, the control signals for turning on the first switch and the second switch are generated. Battery monitoring method.