Battery management system

Abstract

A battery management system (5) for managing a battery pack (10) comprises: a plurality of monitoring circuits (100) for monitoring the battery pack (10); and a management circuit (200) that is connected to each of the plurality of monitoring circuits (100) by wireless communication and manages the battery pack (10). At least one of the plurality of monitoring circuits (100) and / or the management circuit (200) has a measurement circuit (215) for measuring time of flight (TOF) between the monitoring circuit (100) and the management circuit (200) by impulse response ultra wide band (IR-UWB) communication.

Description

Battery Management System

[0001] The present disclosure relates to a battery management system for managing a battery pack.

[0002] Patent document 1 discloses a technology in which, when a functional unit within a battery management system fails to communicate wirelessly with a battery management unit, the functional unit changes the frequency of communication with the battery management unit and re-establishes a wireless communication connection with the battery management unit.

[0003] US Patent Application Publication No. 2020 / 0083722

[0004] However, there is room for improvement in the technology of Patent Document 1.

[0005] Therefore, the present disclosure provides a battery management system that can be further improved.

[0006] A battery management system according to the present disclosure is a battery management system for managing an assembled battery, and includes a plurality of monitoring circuits that monitor the assembled battery, and a management circuit that is connected to each of the plurality of monitoring circuits via wireless communication and manages the assembled battery, and at least one of the plurality of monitoring circuits and the management circuit has a measurement circuit that measures TOF (Time of Flight) between the monitoring circuit and the management circuit via IR-UWB (Impulse Response Ultra Wide Band) communication.

[0007] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to one aspect of the present disclosure, a battery management system that can be further improved can be realized.

[0009] FIG. 1 is a schematic diagram showing a vehicle equipped with a battery management system according to a first embodiment. FIG. 2 is an external view showing an example of a battery management system according to the first embodiment. FIG. 3 is a configuration diagram showing an example of a battery management system according to the first embodiment. FIG. 4 is a diagram showing an example of a waveform of a status signal according to the first embodiment. FIG. 5 is a diagram showing frequency spectra of BLE and UWB according to the first embodiment. FIG. 6 is a schematic diagram showing transmission characteristics of radio waves of BLE and IR-UWB according to the first embodiment. FIG. 7 is a flowchart showing the operation of a battery management system according to a second embodiment. FIG. 8 is a first diagram for explaining a TOF ranging method in a battery management system according to the second embodiment. FIG. 9 is a second diagram for explaining a TOF ranging method in a battery management system according to the second embodiment. FIG. 10A is an example of a table showing distance information between a slave and a master according to the second embodiment. FIG. 10B is a diagram showing an example of a table in which serial positions according to the second embodiment are associated with identification information of monitoring circuits. FIG. 11 is a diagram showing an example of an arrangement of monitoring circuits according to the second embodiment. FIG. 12 is a configuration diagram showing an example of a battery management system according to a modified example of embodiment 2. FIG. 13 is a diagram showing an example of an arrangement of a monitoring circuit according to a modified example of embodiment 2. FIG. 14A is an example of a table showing distance and angle information between a slave and a master according to a modified example of embodiment 2. FIG. 14B is a diagram showing an example of a table in which serial positions according to a modified example of embodiment 2 are associated with identification information of monitoring circuits. FIG. 15 is a schematic diagram showing a vehicle and a terminal device equipped with a battery management system according to embodiment 3. FIG. 16 is a flowchart showing the operation of the battery management system according to embodiment 3.

[0010] Hereinafter, embodiments and the like will be specifically described with reference to the drawings.

[0011] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, component placement positions, 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 described in independent claims are described as optional components.

[0012] 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%).

[0013] Furthermore, the term "on XX (e.g., on a battery pack)" applies not only to cases where two components are arranged at a distance from each other with another component between them, but also to cases where two components are arranged in contact with each other.

[0014] 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.

[0015] First Embodiment A battery management system according to the present embodiment will be described below with reference to FIGS. 1 to 6. FIG.

[0016] The technology disclosed in Patent Document 1 simply changes the frequency of communication with the battery management unit, so if the robustness of the communication is low, there is a risk that the wireless communication connection cannot be re-established.

[0017] However, in some cases, it may be desirable to more reliably transmit desired information between units in a battery management system, such as heartbeats, using wireless communication.

[0018] Therefore, in this embodiment, a battery management system will be described in which units can more reliably communicate wirelessly with each other within the battery management system.

[0019] [1-1. Configuration of Battery Management System] First, the configuration of the battery management system will be described with reference to Figures 1 to 4. Figure 1 is a schematic diagram showing a vehicle 1 equipped with a battery management system 5 (hereinafter also referred to as BMS (Battery Management System) 5) according to the present embodiment.

[0020] As shown in FIG. 1 , the BMS 5 is disposed below the seat 2 of the vehicle 1. Specifically, the BMS 5 is disposed in the space (closed space) between the seat 2 and the chassis 3. This space is a small space. In other words, the BMS 5 is disposed and used in the small space.

[0021] Arranged within this narrow space are an assembled battery including multiple battery cells 11a, a management circuit 200 that manages the assembled battery, and multiple monitoring circuits 100 that monitor the assembled battery. The management circuit 200 and each of the multiple monitoring circuits 100 communicate wirelessly, and a transmission path L is formed within the narrow space. The management circuit 200 is also connected to the assembled battery via a connection box 4.

[0022] The vehicle 1 is, for example, an electric vehicle. The vehicle 1 is, for example, an electric vehicle (EV), but is not limited thereto and may be an electric train or the like.

[0023] FIG. 2 is an external view showing an example of the BMS 5 according to this embodiment.

[0024] The BMS 5 is a system for managing the battery pack. For example, the BMS 5 manages the SOC (State of Charge), SOH (State of Health), and SOP (State of Power) of the battery pack. The BMS 5 also monitors abnormalities in the battery pack. The BMS 5 includes a management circuit 200 that manages the battery pack and multiple monitoring circuits 100 that monitor the battery pack. The BMS 5 may also include a battery pack. For example, the battery pack is configured by connecting multiple battery packs 11 in series or parallel. The battery pack 11 is configured by one or more battery cells 11a. When the battery pack 11 is configured by multiple battery cells 11a, the multiple battery cells 11a are connected in series. For example, the battery cells 11a may be, but are not limited to, lithium-ion batteries. For example, the monitoring circuit 100 is disposed on each of the multiple battery packs 11.

[0025] 2 illustrates an example in which the management circuit 200 is disposed above the junction box 4, but the location of the management circuit 200 is not limited to this. The management circuit 200 may be disposed inside the junction box 4 or on a side surface of the junction box 4, for example. Similarly, while FIG. 2 illustrates an example in which the monitoring circuit 100 is disposed above the battery pack 11, the location of the monitoring circuit 100 is not limited to this. The monitoring circuit 100 may be disposed inside the battery pack 11 or on a side surface of the battery pack 11, for example. In this way, the locations of the management circuit 200 and the monitoring circuit 100 are not limited to the example illustrated in FIG. 2, and any location is possible as long as they can communicate with each other.

[0026] 3 is a configuration diagram showing an example of a BMS 5 according to this embodiment. Although three monitoring circuits 100 are illustrated in FIG. 3, for convenience, the reference numerals of the components included in the monitoring circuits 100 are only illustrated for the monitoring circuit 100 located at the bottom of the page. For example, the three monitoring circuits 100 have the same configuration. Furthermore, the number of monitoring circuits 100 included in the BMS 5 is not particularly limited, and may be one or more.

[0027] As shown in Fig. 3, each of the multiple monitoring circuits 100 includes a battery monitoring unit 110, a wireless communication unit 120, communication antennas 130 and 140, a shunt resistor 7, a relay 8, and a motor 9. Also, in Fig. 3, a connection box 4 is indicated by a dashed line. For example, the battery monitoring unit 110 and the wireless communication unit 120 are implemented by different integrated circuits (ICs), but may also be implemented by a single IC. Also, a specific example of the monitoring circuit 100 is a cell management unit (CMU).

[0028] The battery monitoring unit 110 has a function of monitoring the battery pack 10 , and includes a voltage detection circuit 111 , a temperature measurement circuit 112 , an abnormality diagnosis circuit 113 , a voltage measurement circuit 114 , and a communication interface 115 .

[0029] The voltage detection circuit 111 detects voltage abnormalities in the battery cell 11a (see, for example, FIG. 1). If the battery cell 11a is a lithium-ion battery, the usable voltage range is fixed. The voltage detection circuit 111 is configured to detect an overvoltage, i.e., an exceedance of the upper limit of the usable voltage range of the battery cell 11a, and an undervoltage, i.e., a fall below the lower limit of the usable voltage range of the battery cell 11a. Note that the voltage detection circuit 111 is only required to be configured to be able to detect at least one of an overvoltage and an undervoltage.

[0030] The voltage detection circuit 111 may be configured to have, for example, a comparator provided one-to-one with each of the multiple battery cells 11a, and to detect voltage abnormalities by comparing the voltage of the battery cell 11a with a predetermined voltage in the comparator.

[0031] The temperature measurement circuit 112 and the abnormality diagnosis circuit 113 are circuits for detecting an abnormality in the monitoring circuit 100 (for example, an abnormality in the battery monitoring unit 110).

[0032] The temperature measurement circuit 112 is a circuit for measuring the temperature of the battery monitoring unit 110. The temperature measurement circuit 112 includes a temperature sensor such as a thermistor or a thermocouple.

[0033] The abnormality diagnosis circuit 113 is a circuit that diagnoses an abnormal state in the battery monitoring unit 110 (integrated circuit). The abnormality diagnosis circuit 113 may, for example, compare a predetermined voltage in the battery monitoring unit 110 with a threshold value to diagnose an abnormality in the battery monitoring unit 110, or may diagnose an abnormality in the battery monitoring unit 110 using another method.

[0034] In addition, the voltage detection circuit 111, the temperature measurement circuit 112, and the abnormality diagnosis circuit 113 are configured to output an abnormality signal indicating that an abnormality has been detected to the wireless communication unit 120 (specifically, the control circuit 122) when an abnormality is detected.

[0035] The voltage measurement circuit 114 is a measurement circuit for measuring the voltage of each of one or more battery cells 11a included in the battery pack 11. The voltage measurement results by the voltage measurement circuit 114 are output to the wireless communication unit 120 via the communication interface 115.

[0036] The communication interface 115 is an interface for communication between the wireless communication unit 120 and the battery monitoring unit 110. Note that if the wireless communication unit 120 and the battery monitoring unit 110 are realized by a single IC, the communication interface 115 does not need to be provided.

[0037] The monitoring circuit 100 may include a current monitoring circuit (CMU (Current Monitoring Unit)) that measures the current flowing through the battery pack 10 .

[0038] The wireless communication unit 120 and the communication antennas 130 and 140 are components that allow the monitoring circuit 100 to communicate with the management circuit 200 .

[0039] The wireless communication unit 120 is a wireless communication unit (wireless communication IC) on the slave side in the BMS 5, and includes a communication interface 121, a control circuit 122, a BLE communication circuit 123, a measurement circuit 124, and an IR-UWB (Impulse Response Ultra Wide Band) communication circuit 125.

[0040] The communication interface 121 is an interface for communication between the wireless communication unit 120 and the battery monitoring unit 110. Note that if the wireless communication unit 120 and the battery monitoring unit 110 are realized by a single IC, the communication interface 121 does not need to be provided.

[0041] The control circuit 122 controls each component of the wireless communication unit 120. The control circuit 122 may, for example, transmit data acquired via the communication interface 121 to the management circuit 200 via the BLE communication circuit 123 and the communication antenna 130. Furthermore, when the control circuit 122 acquires an abnormality signal from any of the voltage detection circuit 111, the temperature measurement circuit 112, and the abnormality diagnosis circuit 113, for example, the control circuit 122 may transmit a status signal indicating an abnormality to the management circuit 200 via the IR-UWB communication circuit 125 and the communication antenna 140. Furthermore, when the control circuit 122 does not acquire an abnormality signal from any of the voltage detection circuit 111, the temperature measurement circuit 112, and the abnormality diagnosis circuit 113, for example, the control circuit 122 may transmit a status signal indicating normality to the management circuit 200 via the IR-UWB communication circuit 125 and the communication antenna 140.

[0042] In this way, the control circuit 122 transmits a signal related to the heartbeat to the management circuit 200 via the IR-UWB communication circuit 125, and transmits other signals (for example, data signals) to the management circuit 200 via the BLE communication circuit 123. It can also be said that the control circuit 122 transmits the heartbeat using IR-UWB, and transmits other information using a wireless communication standard other than IR-UWB.

[0043] The BLE communication circuit 123 is connected to the communication antenna 130 (an example of a second communication antenna) and is a communication circuit for transmitting a data signal including a measurement result (e.g., a voltage value) measured by the voltage measurement circuit 114 or the like to the management circuit 200. The BLE communication circuit 123 transmits the data signal to the management circuit 200 via the communication antenna 130.

[0044] The BLE communication circuit 123 performs communication using a wireless communication modulation method different from that of the IR-UWB communication circuit 125. In this embodiment, the BLE communication circuit 123 is configured to perform wireless communication according to the BLE method. The BLE communication circuit 123 performs BLE communication using BLE with the management circuit 200 (specifically, the BLE communication circuit 211). The BLE communication circuit 123 is an example of a second wireless communication circuit. In addition, the BLE communication circuit 123 is an example of another wireless communication unit included in the monitoring circuit 100.

[0045] The modulation method is not limited to the BLE method, and may be, for example, a spread spectrum method, an OFDM (Orthogonal Frequency Division Multiplexing) method, etc. Furthermore, the modulation method used in the BLE communication circuit 123 does not necessarily include the UWB (Ultra Wide Band) method (for example, the IR-UWB method).

[0046] The UWB system is a communication system that transmits power over an extremely wide bandwidth, with a peak transmission power of -41.3 dBm / MHz or less, far lower than the noise level generated by general electronic devices. This enables communication with low interference to other communications and low power consumption. Furthermore, in the case of an IR-UWB system that transmits a pulse signal containing UWB components (e.g., the 3.4 GHz to 4.8 GHz components shown in FIG. 5, which will be described later), the pulse signal is also referred to as an IR-UWB signal. The IR-UWB signal is, for example, a pulse signal containing the frequency components of the UWB signal shown in FIG. 5, which will be described later.

[0047] In the following, an example of communication using the IR-UWB system, which is an example of the UWB system, will be mainly described.

[0048] The measurement circuit 124 is a circuit for measuring the TOF (Time of Flight) between the monitoring circuit 100 and the management circuit 200 by IR-UWB communication, which is communication using the IR-UWB method. Details of the measurement circuit 124 will be described in embodiment 2, etc. In this embodiment, the monitoring circuit 100 does not necessarily have to include the measurement circuit 124.

[0049] The IR-UWB communication circuit 125 is connected to the communication antenna 140 (an example of a first communication antenna) and is a communication circuit for transmitting a status signal indicating the operating status of the battery pack 10 or the monitoring circuit 100 to the management circuit 200. The IR-UWB communication circuit 125 transmits the status signal to the management circuit 200 via the communication antenna 140. Note that the IR-UWB communication circuit 125 does not transmit a data signal to the management circuit 200 via the communication antenna 140.

[0050] The IR-UWB communication circuit 125 is configured to perform wireless communication according to the UWB system. It can also be said that the IR-UWB communication circuit 125 uses a UWB signal (UWB signal) as a status signal that transmits the operating status of the battery pack 10 or the monitoring circuit 100 to the management circuit 200. In this embodiment, the IR-UWB communication circuit 125 is configured to perform wireless communication according to the IR-UWB system. Furthermore, the IR-UWB communication circuit 125 may, for example, broadcast a UWB signal. The IR-UWB communication circuit 125 is an example of a UWB communication unit included in the monitoring circuit 100.

[0051] The IR-UWB communication circuit 125 and the BLE communication circuit 123 are examples of multiple wireless communication units that the monitoring circuit 100 includes and that use different wireless communication modulation methods.

[0052] FIG. 4 is a diagram showing an example of the waveform of an IR-UWB signal according to this embodiment.

[0053] The IR-UWB communication circuit 125 periodically transmits an IR-UWB signal as shown in FIG. 4 to the management circuit 200 as a status signal.

[0054] The IR-UWB communication circuit 125 transmits the operating status of the battery pack 10 or the monitoring circuit 100 to the management circuit 200 by, for example, changing the form of the signal shown in Fig. 4. The IR-UWB communication circuit 125 transmits the operating status by, for example, the presence or absence of repeatedly transmitted impulse signals, a change in the transmission time interval of the impulse signals, or a change in the repetition period of the impulse signals, but the form of the status signal is not limited to these.

[0055] The operating state includes whether the battery pack 10 or the monitoring circuit 100 is in a normal state or an abnormal state. Furthermore, an abnormal state in the battery pack 10 includes at least one of an overvoltage and an undervoltage of the battery pack 10. For example, the IR-UWB communication circuit 125 may transmit a state signal in a different manner in the normal state and the abnormal state. In this way, the IR-UWB communication circuit 125 is configured to transmit a heartbeat to the management circuit 200 as a pulse signal. The IR-UWB communication circuit 125 is an example of a first wireless communication circuit.

[0056] 3 again, the management circuit 200 includes a wireless communication unit 210, an MCU (Micro Controller Unit) 220, communication antennas 230 and 240, a current measurement circuit 260, and a communication circuit 270. For example, the wireless communication unit 210 and the MCU 220 are realized by different ICs, but may also be realized by a single IC. Furthermore, a specific example of the management circuit 200 is a BMU (Battery Management Unit).

[0057] The wireless communication unit 210 and the communication antennas 230 and 240 are components that allow the management circuit 200 to communicate with the monitoring circuit 100 .

[0058] The wireless communication unit 210 is a master-side wireless communication unit (wireless communication IC) in the BMS 5, and includes a BLE communication circuit 211, a control circuit 212, a communication interface 213, an IR-UWB communication circuit 214, and a measurement circuit 215.

[0059] The BLE communication circuit 211 is a communication circuit that is connected to a communication antenna 230 (an example of a fourth communication antenna) and receives a data signal from the monitoring circuit 100. The BLE communication circuit 211 receives a data signal from each of the multiple monitoring circuits 100 via the communication antenna 230.

[0060] The BLE communication circuit 211 performs communication using a wireless communication modulation method different from that of the IR-UWB communication circuit 214. In this embodiment, the BLE communication circuit 211 is configured to perform wireless communication according to the BLE method. The BLE communication circuit 211 performs BLE communication using BLE with the monitoring circuit 100 (specifically, the BLE communication circuit 123). The BLE communication circuit 211 is an example of another wireless communication unit included in the management circuit 200.

[0061] The modulation method is not limited to the BLE method, and may be, for example, a spread spectrum method, an OFDM method, etc. Furthermore, the modulation method used in the BLE communication circuit 211 does not have to include the UWB method (for example, the IR-UWB method). The BLE communication circuit 211 is an example of a fourth wireless communication circuit.

[0062] The control circuit 212 controls the components of the wireless communication unit 210. The control circuit 212 executes various processes based on, for example, signals acquired by the BLE communication circuit 211 and the IR-UWB communication circuit 214. The control circuit 212 outputs a data signal acquired via the BLE communication circuit 211 to the control circuit 222 via the communication interfaces 213 and 221. The control circuit 212 also outputs a status signal acquired via the IR-UWB communication circuit 214 to the control circuit 222.

[0063] In this way, the control circuit 212 receives signals related to heartbeats from each monitoring circuit 100 via the IR-UWB communication circuit 214, and receives other signals (for example, data signals) from each monitoring circuit 100 via the BLE communication circuit 211. It can also be said that the control circuit 212 receives heartbeats using IR-UWB, and receives other information using wireless communication standards other than IR-UWB.

[0064] The communication interface 213 is an interface for communication between the wireless communication unit 210 and the MCU 220. If the wireless communication unit 210 and the MCU 220 are realized by a single IC, the communication interface 213 does not need to be provided.

[0065] The IR-UWB communication circuit 214 is connected to a communication antenna 240 (an example of a third communication antenna) and is a communication circuit for receiving status signals from each monitoring circuit 100 .

[0066] The IR-UWB communication circuit 214 is configured to perform wireless communication according to the UWB system. It can also be said that the IR-UWB communication circuit 214 receives a status signal from the monitoring circuit 100 using the UWB system. In this embodiment, the IR-UWB communication circuit 214 is configured to perform wireless communication according to the IR-UWB system. The IR-UWB communication circuit 214 performs IR-UWB communication with the monitoring circuit 100 (specifically, the IR-UWB communication circuit 125). The IR-UWB communication circuit 214 receives, for example, an IR-UWB signal as shown in FIG. 4 from the IR-UWB communication circuit 125 as a status signal. The IR-UWB communication circuit 214 is an example of a third wireless communication circuit. The IR-UWB communication circuit 214 is also an example of a UWB communication unit included in the management circuit 200.

[0067] The IR-UWB communication circuit 214 and the BLE communication circuit 211 are examples of a plurality of wireless communication units included in the management circuit 200 that use different wireless communication modulation methods.

[0068] The measurement circuit 215 is a circuit for measuring the TOF between each of the multiple monitoring circuits 100 and the management circuit 200 through IR-UWB communication. Details of the measurement circuit 215 will be described in embodiment 2 etc. In this embodiment, the management circuit 200 does not necessarily have to include the measurement circuit 215.

[0069] The MCU 220 is a component for managing the battery pack 10 , and includes a communication interface 221 , a control circuit 222 , a CAN (Controller Area Network) interface 223 , and a storage circuit 224 .

[0070] The communication interface 221 is an interface for communication between the wireless communication unit 210 and the MCU 220. If the wireless communication unit 210 and the MCU 220 are realized by a single IC, the communication interface 221 does not need to be provided.

[0071] The control circuit 222 controls each component of the MCU 220. The control circuit 222 uses a first management table stored in the memory circuit 224 to identify the voltage value of the battery cell 11a included in the data signal transmitted from the monitoring circuit 100 and the position of the battery cell 11a in the battery pack 11. The first management table is, for example, a table that indicates the correspondence between the position of the battery pack 11 and the identification information of the wireless communication unit 120 included in the monitoring circuit 100 (e.g., identification information used for BLE communication).

[0072] Furthermore, the control circuit 222 uses a second management table stored in the memory circuit 224 to identify in which monitoring circuit 100 the abnormality indicated in the status signal transmitted from the monitoring circuit 100 has occurred.

[0073] The CAN interface 223 is an interface for communication between the MCU 220 and the CAN. The MCU 220 is connected to the CAN via the CAN interface 223.

[0074] The memory circuit 224 is a general-purpose or dedicated electrical circuit that stores information used by the control circuit 222 to perform information processing. The memory circuit 224 may be a volatile memory or a non-volatile memory. For example, the memory circuit 224 stores a first management table and a second management table.

[0075] The current measurement circuit 260 detects the current flowing through the battery pack 10. The current measurement circuit 260 is a resistance detection type current sensor that uses a shunt resistor 7, but may also be a magnetic field detection type current sensor. The current measurement circuit 260 may be configured to include an IC for current measurement.

[0076] The communication circuit 270 is a circuit that connects the current measuring circuit 260 and the control circuit 222 so that they can communicate with each other.

[0077] In the above, an example has been described in which two types of modulation methods are used for wireless communication between the monitoring circuit 100 and the management circuit 200, but this is not limiting and three or more types may be used. Furthermore, at least one of the two or more types of modulation methods used for wireless communication between the monitoring circuit 100 and the management circuit 200 includes the UWB method, and at least one includes a modulation method other than UWB.

[0078] In such a BMS 5, wireless communication is performed within the BMS 5 using the UWB system, which is less susceptible to interference, etc., thereby improving the robustness of communication within the BMS 5. Therefore, within the BMS 5, units can more reliably transmit information via wireless communication. For example, the monitoring circuit 100 can more reliably transmit information to the management circuit 200 using wireless communication.

[0079] The shunt resistor 7 is a current detection resistor for detecting the current flowing in the series circuit of the battery pack 10 and the motor 9. The shunt resistor 7 is connected in series with the battery pack 10. In the example of Fig. 3, the shunt resistor 7 is connected between the positive electrode of the battery pack 10 and the motor 9. The resistance value of the shunt resistor 7 is not particularly limited.

[0080] The relay 8 is a switch for interrupting the current flowing through the power line connecting the battery pack 10 and the motor 9. For example, when the current monitored by the current measurement circuit 260 is determined to be abnormal, the relay 8 is turned off to interrupt the current flowing through the power line.

[0081] The motor 9 is an example of a load to which power is supplied from the battery pack 10. The motor 9 is, for example, a drive motor for an electric vehicle. The battery pack 10 and the motor 9 are connected via a power line. Note that the load is not limited to the motor 9.

[0082] [1-2. Characteristics of Various Signals] Next, various signals according to this embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing frequency spectra of BLE and UWB according to this embodiment. The vertical axis of Fig. 5 represents transmission power, and the horizontal axis represents frequency.

[0083] As shown in Fig. 5, the BLE signal is a signal having a peak at 2.4 GHz, whereas the UWB signal is a broad signal having components in a wide band from 3.4 GHz to 4.8 GHz (microwave low band). The UWB signal, for example, does not include the peak frequency of the BLE signal, but includes frequency components higher than the peak frequency of the BLE signal. Furthermore, the transmission power of the peak frequency of the UWB signal is lower than the transmission power of the peak frequency of the BLE signal. Furthermore, when the IR-UWB signal is subjected to FFT (Fast Fourier Transform), for example, a wideband waveform from 3.4 GHz to 4.8 GHz as shown in Fig. 5 is obtained.

[0084] The frequency band of the UWB signal is not limited to the example shown in Fig. 5 and may be, for example, 7.25 to 10.25 GHz (high microwave band).Furthermore, a frequency band other than the above may be used as the frequency band of the UWB signal depending on the country, region, etc.

[0085] 6 is a schematic diagram showing the transmission characteristics of BLE and IR-UWB radio waves according to this embodiment. The vertical axis of FIG. 6 represents VSWR (Voltage Standing Wave Ratio), and the horizontal axis represents the distance from the signal source.

[0086] As shown in Figure 6, a BLE signal on a specific channel in a narrow space has the characteristic of having antinodes and nodes in the voltage standing wave ratio depending on the distance. This characteristic is thought to be due to the fact that reflection of the BLE signal in a narrow space causes standing waves and multipath interference. BLE signals are also susceptible to interference, and communication quality is likely to deteriorate when there is interference around 2.4 GHz. This can cause communication interruptions or communication errors with BLE signals.

[0087] On the other hand, since an IR-UWB signal is a signal having wideband components as shown in Figure 5, it has a characteristic of gradually declining to the right compared to a BLE signal (a characteristic that antinodes and nodes are less likely to occur in the voltage standing wave ratio). IR-UWB signals are also less susceptible to interference, and communication quality is less likely to deteriorate even if there is an interfering wave of a specific frequency, for example. In other words, IR-UWB signals can reduce the occurrence of standing waves and multipath.

[0088] Therefore, even if the BLE communication is interrupted, the IR-UWB communication is not interrupted and communication can continue. For example, in the BMS 5, even if the BLE communication is interrupted, it is possible to transmit the heartbeat to the management circuit 200 by IR-UWB communication. This makes it possible to transmit the heartbeat to the management circuit 200 more reliably.

[0089] In this way, in the BMS 5, signals having different transmission characteristics are used for the communication between the BLE communication circuits 123 and 211 and the communication between the IR-UWB communication circuits 125 and 214. In the present embodiment, a signal having transmission characteristics different from that of an IR-UWB signal is used for the communication between the BLE communication circuits 123 and 211.

[0090] Although the above describes an example in which a signal indicating a heartbeat is transmitted to the management circuit 200 using IR-UWB communication, a signal indicating other information may also be transmitted to the management circuit 200 using IR-UWB communication. The other information may include, for example, binary information (e.g., normal / abnormal, ON / OFF, etc.) related to the battery pack 10 or the monitoring circuit 100.

[0091] (Embodiment 2) A battery management system (BMS) according to this embodiment will be described below with reference to Figures 7 to 11. Note that the following description will focus on differences from embodiment 1, and descriptions of content that is the same as or similar to embodiment 1 will be omitted or simplified. Each component of the BMS according to this embodiment may be the same as the BMS 5 according to embodiment 1, and the following description will use the reference numerals of embodiment 1 to designate each component.

[0092] As shown in the first embodiment, the battery pack 10 includes a plurality of battery packs 11, and a monitoring circuit 100 is provided for each of the plurality of battery packs 11. The management circuit 200 acquires data such as the voltage value of each battery cell 11a from each monitoring circuit 100, but in order to manage this data, information is required as to which battery pack 11 (or battery cell 11a) the data belongs to. In other words, information indicating the correspondence between the battery pack 11 (or battery cell 11a) and the monitoring circuit 100 is required.

[0093] Although it is possible for an operator or the like to create a table showing the correspondence between the battery packs 11 and the monitoring circuits 100 and store the table in the management circuit 200, this is time-consuming. Therefore, in this embodiment, a BMS that can automatically create the table will be described.

[0094] [2-1. Operation of Battery Management System] First, the operation of the BMS according to this embodiment will be described with reference to Figs. 7 to 10B. Fig. 7 is a flowchart showing the operation (control method) of the BMS according to this embodiment. The operation shown in Fig. 7 is executed, for example, after the monitoring circuit 100 is installed on each battery pack 11.

[0095] 7 , first, the BMS performs pairing by BLE communication (S10). In step S10, the control circuit 222 performs pairing by BLE communication between the BLE communication circuit 123 of each of the multiple monitoring circuits 100 and the BLE communication circuit 211 of the management circuit 200. Through this pairing, the control circuit 222 can acquire the slave ID (identification information) of each monitoring circuit 100.

[0096] The identification information may be information used by the BLE communication circuit 123 in the monitoring circuit 100. The identification information may be, for example, information used in BLE communication between the BLE communication circuits 123 and 211 in the monitoring circuit 100. For example, the identification information may be the MAC address or IP address of each monitoring circuit 100, or other information unique to each monitoring circuit 100. The control circuit 222 stores the identification information (pairing information) of each monitoring circuit 100 obtained by pairing in the memory circuit 224.

[0097] At this point, it is not yet possible to identify the placement positions of the monitoring circuits 100. In addition, the control circuit 222 may calculate the distance between the monitoring circuits 100 by BLE communication in step S10.

[0098] Next, the BMS measures the distance between each slave (each monitoring circuit 100) via IR-UWB communication (S20). In step S20, the control circuit 222 measures the distance between each monitoring circuit 100 and the management circuit 200. The control circuit 222 calculates the distance between each monitoring circuit 100 and the management circuit 200 by measuring the TOF between each monitoring circuit 100 and the management circuit 200 via IR-UWB communication.

[0099] 8 and 9 are diagrams for explaining the TOF ranging method in the BMS according to this embodiment. Either of the TOF ranging methods shown in Fig. 8 and Fig. 9 may be used, but from the viewpoint of measurement accuracy, it is preferable to use the method shown in Fig. 9.

[0100] 8 and 9 illustrate simplified configurations of the monitoring circuit 100 and the management circuit 200. For convenience, in FIGS. 8 and 9, the BLE communication circuits 123 and 211 are referred to as "BLE," the IR-UWB communication circuits 125 and 214 are referred to as "IR-UWB," the wireless communication units 120 and 210 are referred to as "wireless communication ICs," the battery monitoring unit 110 is referred to as "battery monitoring IC," and the MCU 220 is referred to as "battery control MCU." Each ranging pulse signal and received pulse signal is an IR-UWB signal. In FIGS. 8 and 9, the downward direction from the top of the page indicates the flow of time.

[0101] The SS-TWR (Single-Sided Two-Way Ranging) method shown in FIG. 8 is a method in which TOF measurement is performed on the management circuit 200 side (BMC side).

[0102] In this case, the IR-UWB communication circuit 214 of the management circuit 200 transmits a ranging pulse signal via the communication antenna 240. The IR-UWB communication circuit 125 of the monitoring circuit 100 receives the ranging pulse signal transmitted from the management circuit 200 and transmits a received pulse signal indicating the reception to the management circuit 200 via the communication antenna 140. The IR-UWB communication circuit 214 of the management circuit 200 receives the received pulse signal transmitted from the monitoring circuit 100. The measurement circuit 215 measures the time from transmitting the ranging pulse signal to receiving the received pulse signal as the TOF. In other words, the measurement circuit 215 measures the TOF between the monitoring circuit 100 and the management circuit 200 through IR-UWB communication (see the bold arrow in FIG. 8 ).

[0103] In the case of the system shown in FIG. 8, the monitoring circuit 100 does not need to include the measuring circuit 124.

[0104] The DS-TWR (Double-Sided Two-Way Ranging) method shown in FIG. 9 is a method in which TOF measurements are performed on both the monitoring circuit 100 side (CMU side) and the management circuit 200 side (BMU side).

[0105] In this case, the IR-UWB communication circuit 214 of the management circuit 200 transmits a ranging pulse signal (first ranging pulse signal) via the communication antenna 240. The IR-UWB communication circuit 125 of the monitoring circuit 100 receives the first ranging pulse signal transmitted from the management circuit 200 and, in response to the reception, transmits a ranging pulse signal (second ranging pulse signal) to the management circuit 200 via the communication antenna 140. The IR-UWB communication circuit 214 of the management circuit 200 receives the second ranging pulse signal transmitted from the monitoring circuit 100. The measurement circuit 215 measures the time from transmitting the first ranging pulse signal to receiving the second ranging pulse signal as TOF (see the bold arrow on the management circuit 200 side in FIG. 9 ).

[0106] Furthermore, in response to receiving the second ranging pulse signal transmitted from the monitoring circuit 100, the IR-UWB communication circuit 214 of the management circuit 200 transmits a ranging pulse signal (third ranging pulse signal) to the monitoring circuit 100 via the communication antenna 240. The IR-UWB communication circuit 125 of the monitoring circuit 100 receives the third ranging pulse signal transmitted from the management circuit 200. The measurement circuit 124 measures the time from transmitting the second ranging pulse signal to receiving the third ranging pulse signal as TOF (see the thick arrow on the monitoring circuit 100 side in FIG. 9 ).

[0107] The TOF measured by the measurement circuit 124 may be transmitted to the management circuit 200 by, for example, BLE communication.

[0108] 8 and 9, the TOF measurement is sequentially performed by each monitoring circuit 100. For example, the management circuit 200 transmits identification information of the target monitoring circuit 100 for which the TOF measurement is to be performed to each monitoring circuit 100 using BLE communication. This allows only the target monitoring circuit 100 to return a signal in response to the ranging pulse from the management circuit 200.

[0109] The control circuit 222 calculates the distance between each monitoring circuit 100 and the management circuit 200 based on the TOF measured by the method shown in Fig. 8 or 9. Then, the control circuit 222 may store at least one of the acquired TOF and the distance calculated based on the TOF in the memory circuit 224 in association with the identification information of the monitoring circuit 100.

[0110] 7 again, next, the control circuit 222 sorts the slave IDs in order of distance (S30). The control circuit 222 sorts the identification information of each monitoring circuit 100 acquired in step S10 in order of distance measured in step S20. As a result, the identification information of each monitoring circuit 100 is arranged in a row, for example, in order of proximity to the management circuit 200.

[0111] 10A is a diagram showing an example of a table (first table) showing distance information between the slave and the master according to this embodiment. The table shown in Fig. 10A is acquired before step S10 is executed, for example, before the monitoring circuit 100 is placed in the battery pack 10, and is stored in the memory circuit 224. The table shown in Fig. 10A is an example of a position information database.

[0112] As shown in FIG. 10A, the table includes items such as CMU, serial position, and distance.

[0113] CMU is a virtual address of the location of the monitoring circuit 100 assigned in the management circuit 200 .

[0114] The serial position is information indicating the relative positional relationship of the distance from the management circuit 200, and is configured by arranging eight of them in a row, from "1 (Lower)" which is closest to the management circuit 200 to "8 (Upper)" which is farthest from the management circuit 200. The serial position is an example of position information indicating the relative relationship of the positions where multiple monitoring circuits 100 are arranged.

[0115] Note that information indicating the battery pack 11 (or battery cell 11a) corresponding to each serial position is acquired in advance and stored in the memory circuit 224. In other words, if the control circuit 222 knows in which serial position the monitoring circuit 100 is placed, it can identify which battery pack 11 the data signal from the monitoring circuit 100 is measuring.

[0116] The distance indicates a distance determined based on a position where the monitoring circuit 100 can be physically placed in the BMS and the position of the management circuit 200. The distance can be obtained, for example, during the design stage of the BMS. In other words, the distance is obtained before the monitoring circuit 100 is placed in the battery pack 10.

[0117] In this embodiment, the monitoring circuits 100 are designed to be arranged at intervals of 200 mm from the management circuit 200. An example of the arrangement of the monitoring circuits 100 will be described later with reference to FIG.

[0118] In this way, the table shown in Figure 10A is a table that links the positions at which each of the multiple monitoring circuits 100 is placed and the distance between the management circuits 200, with positional information that indicates the relative relationship between the positions at which the multiple monitoring circuits 100 are placed.

[0119] 10A illustrates an example in which the monitoring circuits 100 in the BMS are arranged so that they are at different distances from the management circuit 200. Note that the monitoring circuits 100 are not limited to being arranged so that they are at different distances from the management circuit 200, and at least two monitoring circuits 100 may be arranged so that they are at equal distances from the management circuit 200. Here, "equal" includes not only cases in which the distances are completely the same, but also cases in which there is a distance error (for example, about several percent or about 10%) depending on the measurement accuracy of the measurement by the measurement circuit 215 or the like.

[0120] The control circuit 222 may determine whether the distance measured in step S20 is within a predetermined range, for example, using the table shown in FIG. 10A . The control circuit 222, for example, arranges the identification information of each monitoring circuit 100 in a row in order of proximity from the management circuit 200, determines whether the distance to the closest monitoring circuit 100 is within a predetermined range including 200 mm, and determines whether the distance to the next closest monitoring circuit 100 is within a predetermined range including 400 mm. The control circuit 222 performs this determination for each monitoring circuit 100. If there is a monitoring circuit 100 that is outside the predetermined range, it is possible that the distance measurement has failed, and the control circuit 222 may measure the distance for that monitoring circuit 100 again.

[0121] Next, the control circuit 222 creates a table (second table) of each slave ID and the serial position of the battery (S40). The control circuit 222 creates the second table based on the table showing the slave-master distance information (table shown in FIG. 10A) and the identification information of each monitoring circuit 100 sorted in step S30.

[0122] 10B is a diagram illustrating an example of a table (second table) according to the present embodiment in which the serial positions are associated with the identification information of the monitoring circuit 100. In the example of FIG. 10B, the identification information of the monitoring circuit 100 includes a MAC address.

[0123] As shown in FIG. 10B, in this embodiment, the control circuit 222 creates a table in which the serial position is associated with the MAC address of the monitoring circuit 100.

[0124] 10B by associating the serial positions shown in FIG. 10A with the identification information of each monitoring circuit 100 sorted in order of distance. When the identification information of the monitoring circuits 100 is sorted in order of distance, the control circuit 222 associates the serial position "1 (Lower)" with the identification information at the top (the identification information of the monitoring circuit 100 with the shortest distance). Next, the control circuit 222 associates the serial position "2" with the identification information second from the top (the identification information of the monitoring circuit 100 with the second shortest distance).

[0125] In this way, the control circuit 222 creates the table shown in FIG. 10B by sequentially associating the serial positions with the identification information of the monitoring circuits 100.

[0126] Note that creating the table shown in FIG. 10B corresponds to linking the identification information of each monitoring circuit 100 with the position of the battery pack 11 (or battery cell 11a).

[0127] The order of the MAC addresses (an example of identification information) shown in FIG. 10B matches the order of the MAC addresses of the monitoring circuits 100 rearranged in step S30.

[0128] The control circuit 222 stores the table (second table) created in step S40 in the memory circuit 224.

[0129] An example of the layout of the monitoring circuit 100 in the BMS 5a according to this embodiment will now be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of the layout of the monitoring circuit 100 according to this embodiment. Fig. 11 shows an example of the layout of eight monitoring circuits, 101 to 108 (CMU1 to CMU8), as viewed from above the vehicle 1.

[0130] 11 , in the BMS 5a according to this embodiment, the monitoring circuits 100 are arranged so that their distances to the management circuit 200 are different from one another. For example, the monitoring circuits 100 are arranged in a zigzag pattern when viewed from above. As a result, since there are no monitoring circuits 100 at equal distances, the arrangement positions of the monitoring circuits 100 can be identified by measuring only the distances.

[0131] 11 , the serial position “1 (Lower)” is associated with the identification information of the monitoring circuit 101, the serial position “2” is associated with the identification information of the monitoring circuit 102, the serial position “3” is associated with the identification information of the monitoring circuit 103, and the serial position “4” is associated with the identification information of the monitoring circuit 104. Furthermore, the serial position “5” is associated with the identification information of the monitoring circuit 105, the serial position “6” is associated with the identification information of the monitoring circuit 106, the serial position “7” is associated with the identification information of the monitoring circuit 107, and the serial position “8 (Upper)” is associated with the identification information of the monitoring circuit 108.

[0132] Although Figure 11 shows an example in which the monitoring circuits 100 are arranged in two rows in the vertical direction of the paper, they may also be arranged in only one row, or in three or more rows.

[0133] (Modification of Second Embodiment) A battery management system (BMS) according to this modification will be described below with reference to Figures 12 to 14B. Note that the following description will focus on differences from the second embodiment, and descriptions of content that is the same as or similar to the second embodiment will be omitted or simplified.

[0134] Fig. 12 is a configuration diagram showing an example of a BMS 5b according to this modification. The BMS 5b according to this modification differs from the BMS 5a according to the second embodiment in that it includes communication antennas 150 and 250. Note that Fig. 12 shows a schematic configuration of a battery monitoring unit 110, wireless communication units 120 and 210, and an MCU 220.

[0135] 12, the monitoring circuit 100b includes a communication antenna 150 in addition to the communication antenna 140 as a communication antenna connected to the IR-UWB communication circuit 125. The management circuit 200b also includes a communication antenna 250 in addition to the communication antenna 240 as a communication antenna connected to the IR-UWB communication circuit 214.

[0136] The communication antennas 240 and 250 are used to measure the distance between each monitoring circuit 100b and the management circuit 200b using IR-UWB communication. In this way, the management circuit 200b is provided with a plurality of communication antennas for IR-UWB communication.

[0137] The communication antennas 140 and 150 are used to measure the distance between the monitoring circuit 100b and the management circuit 200b using IR-UWB communication. Specifically, the communication antenna 140 is used when the management circuit 200b measures the distance using the communication antenna 240 through IR-UWB communication, and the communication antenna 150 is used when the management circuit 200b measures the distance using the communication antenna 250 through IR-UWB communication. In this way, the monitoring circuit 100b is equipped with multiple communication antennas for IR-UWB communication. Note that, in cases where the communication antennas 240 and 250 transmit IR-UWB signals in a time-division manner, the monitoring circuit 100b only needs to be equipped with one of the communication antennas 140 and 150.

[0138] 13 is a diagram showing an example of the arrangement of a monitoring circuit 100b according to this modification. The monitoring circuits 101b and 102b shown in FIG. 13 are the same distance from the management circuit 200b. Similarly, the monitoring circuits 103b and 104b, the monitoring circuits 105b and 106b, and the monitoring circuits 107b and 108b are also the same distance from the management circuit 200b.

[0139] In this manner, in this modification, at least two of the monitoring circuits 100b are arranged at equal distances from the management circuit 200b.

[0140] As shown in FIG. 13 , the communication antennas 240 and 250 are positioned at different distances from the respective monitoring circuits 101b to 108b. The communication antennas 240 and 250 are, for example, positioned at a predetermined interval. The communication antennas 240 and 250 are, for example, positioned side by side parallel to the direction in which the monitoring circuits 101b and 102b, which are positioned at equal distances from the management circuit 200b, are aligned. The communication antennas 240 and 250 are positioned so that the line connecting the communication antenna 240 and one of the monitoring circuits 100b is not parallel to the dashed line connecting the communication antenna 250 and that one of the monitoring circuits 100b. This makes it possible to calculate the angle (relative angle) between the management circuit 200b and the monitoring circuit 100b using trigonometry. This angle is, for example, the angle between the direction in which CMUs 1, 3, 5, and 7 are aligned (the vertical direction on the paper) and the line connecting the monitoring circuit 100b and the management circuit 200b. The angle is, for example, 90° or less.

[0141] Fig. 14A is an example of a table showing distance and angle information between the slave and the master according to this modification. The table shown in Fig. 14A is acquired before step S10 shown in Fig. 7 is executed, for example, before the monitoring circuit 100b is placed in the battery pack 10, and is stored in the memory circuit 224. The table shown in Fig. 14A is an example of a position information database.

[0142] As shown in FIG. 14A, the table includes the following entries: CMU, serial position, distance, and angle.

[0143] The angle is the angle formed by the vertical direction of the paper and the line segment connecting the monitoring circuit 100b and the management circuit 200b in the case of Fig. 13. Furthermore, the angles between the monitoring circuits 100b and the management circuits 200b arranged in CMUs 2, 4, 6, and 8 are calculated as positive angles, for example, and the angles between the monitoring circuits 100b and the management circuits 200b arranged in CMUs 1, 3, 5, and 7 are calculated as negative angles, for example.

[0144] In this modified example, as shown in FIG. 13, two monitoring circuits 100b are arranged 400 mm apart from a position 200 mm from the management circuit 200b. However, by using the angle, it is possible to distinguish in which position (for example, on the left or right) two monitoring circuits 100b that are the same distance from the management circuit 200b are arranged.

[0145] The control circuit 222 measures the distance and angle of each slave (each monitoring circuit 100b) through IR-UWB communication, for example, in step S20 shown in FIG.

[0146] 7, the control circuit 222 sorts the slave IDs in order of distance and angle. For example, the control circuit 222 sorts the identification information of the monitoring circuits 100b in order of distance and angle (negative, then positive). When there are two pieces of identification information of the monitoring circuits 100b that are the same distance apart, the control circuit 222 sorts the identification information of the monitoring circuits 100b in order of distance and angle (negative, then positive). When there are two pieces of identification information of the monitoring circuits 100b that are the same distance apart, the control circuit 222 sorts the identification information of the monitoring circuits 100b in order of distance and angle (negative, then positive).

[0147] 7, the control circuit 222 creates a table (second table) of each slave ID and the serial position of the battery pack 11. The control circuit 222 creates the second table based on the table (table shown in FIG. 14A) indicating the distance and angle information between the slave and the master, and the identification information of each monitoring circuit 100b rearranged in step S30 in this modification.

[0148] 14B is a diagram showing an example of a table (second table) in which serial positions according to this modification are associated with identification information of the monitoring circuit 100b. In the example of FIG. 14B, the identification information of the monitoring circuit 100b includes a MAC address.

[0149] 14B, in this modification, the control circuit 222 creates a table in which the serial position is associated with the MAC address of the monitoring circuit 100b. The serial position is an example of information based on the TOF measurement value obtained by IR-UWB communication, and the MAC address of the monitoring circuit 100b is an example of identification information used for communication in other wireless communication units.

[0150] In step S40, the control circuit 222 calculates the angle of each of the multiple monitoring circuits 100b and the management circuit 200b based on the distance between each of the multiple monitoring circuits 100b and the management circuit 200b in each of the multiple communication antennas, and creates a second table based on the calculated angle. Specifically, in step S40, the control circuit 222 creates the table shown in FIG. 14B by associating the serial positions shown in FIG. 14A with the identification information of each monitoring circuit 100b sorted in order of distance and angle. When the identification information of the monitoring circuits 100b is sorted in order of shortest distance and smallest angle (e.g., negative angle, then positive angle), the control circuit 222 associates the serial position "1 (Lower)" with the uppermost identification information (in the example of FIG. 14B, this is 00-AA-BB-CC-DD-06, e.g., the identification information of the monitoring circuit 100b with the shortest distance and negative angle). Next, the control circuit 222 associates the serial position "2" with the second-highest identification information (00-AA-BB-CC-DD-02 in the example of FIG. 14B, for example, the identification information of the monitoring circuit 100b with the shortest distance and positive angle). Next, the control circuit 222 associates the serial position "3" with the third-highest identification information (00-AA-BB-CC-DD-00 in the example of FIG. 14B, for example, the identification information of the monitoring circuit 100b with the second-lowest distance and negative angle).

[0151] In this way, the control circuit 222 creates the table shown in Fig. 14B by sequentially associating the serial positions with the identification information of the monitoring circuits 100b. It can also be said that the control circuit 222 creates a second table that links the identification information of each monitoring circuit 100b with its serial position (position information) based on the distance and angle between each monitoring circuit 100b and the management circuit 200b acquired by measurement using IR-UWB communication and the table shown in Fig. 14A.

[0152] The table shown in FIG. 14B may be the same as the table shown in FIG. 10B.

[0153] The control circuit 222 stores the table created in step S40 according to this modification in the storage circuit 224.

[0154] (Embodiment 3) A battery management system (BMS) according to this embodiment will be described below with reference to Figures 15 and 16. Note that the following description will focus on differences from embodiment 1, and descriptions of content that is the same as or similar to embodiment 1 will be omitted or simplified. Each component of the BMS according to this embodiment may be the same as the BMS 5 according to embodiment 1, and the following description will use the reference numerals of embodiment 1 to designate each component.

[0155] As described in the first embodiment, the battery pack 10 includes a plurality of battery packs 11, and a monitoring circuit 100 is provided for each of the plurality of battery packs 11. The management circuit 200 acquires data such as the voltage value of each battery cell 11a from each monitoring circuit 100 and controls the battery pack 10. However, there is a risk that this data may be transmitted from an unauthorized device. This could make it possible to control the battery pack 10 from outside the vehicle 1, for example. Therefore, in this embodiment, a BMS that can distinguish between data transmitted from an unauthorized device and data transmitted from the monitoring circuit 100 will be described.

[0156] The unauthorized device may be a terminal device owned by a malicious user, or may be a terminal device that is remotely controlled by hacking, etc. The terminal device may be a mobile terminal such as a smartphone, or may be a fixed in-vehicle device that has a communication function, such as a navigation system.

[0157] [3-1. Configuration of Battery Management System] First, the configuration of the battery management system will be described with reference to Fig. 15. Fig. 15 is a schematic diagram showing a vehicle 1 equipped with a battery management system 5c (hereinafter also referred to as BMS 5c) according to the present embodiment, and a terminal device 6.

[0158] As shown in Fig. 15, a BMS 5c is mounted on a vehicle 1. A terminal device 6 is also present in the vehicle 1 in a state capable of wireless communication with the BMS 5c (specifically, the management circuit 200). The terminal device 6 is assumed to have been hacked and to be transmitting data for unauthorized control of the BMS 5c, for example, via BLE communication. The terminal device 6 may also be present outside the vehicle 1 as long as it is capable of wireless communication with the management circuit 200.

[0159] The terminal device 6 is configured to be able to perform, for example, BLE communication and IR-UWB communication.

[0160] At least one of the measurement circuits 124 and 215 measures the distance between the management circuit 200 and the terminal device 6 by IR-UWB communication.

[0161] The control circuit 222 determines whether the terminal device 6 is an unauthorized device based on the distance measured by the measurement circuit 215 and a table created in advance (for example, the table shown in FIG. 10A or FIG. 14A).

[0162] The storage circuit 224 stores a table containing the distances between the monitoring circuit 100 and the management circuit 200 .

[0163] [3-2. Operation of Battery Management System] Next, the operation of the BMS 5c configured as described above will be described with reference to FIG. 16. FIG. 16 is a flowchart showing the operation (control method) of the BMS 5c according to this embodiment. FIG. 16 shows the operation of the management circuit 200 to determine the authenticity of data received. It is assumed that the table shown in FIG. 10A or FIG. 14A is pre-stored in the memory circuit 224 of the management circuit 200. The control circuit 222 executes the process shown in FIG. 16 when data is received from the monitoring circuit 100 and when data is received from the terminal device 6.

[0164] 16, the control circuit 222 measures the distance of the slave through IR-UWB communication (S110). The control circuit 222 measures the distance between the device that received the data (for example, terminal device 6 in the example of FIG. 15) and the management circuit 200 through IR-UWB communication. The devices include the monitoring circuit 100 and the terminal device 6.

[0165] Next, the control circuit 222 compares the distance measured in step S110 with the slave's position information database (S120) and determines whether the measured distance matches the position information database (S130). The control circuit 222 determines that the distance (or distance and angle) measured in step S110 matches the distance included in the table shown in Fig. 10A (or the distance and angle included in the table shown in Fig. 14A) or the difference is within a predetermined range.

[0166] Next, if the control circuit 222 determines that the data matches the location information database (Yes in S130), it determines that the communication is from the correct destination (S140), and if it determines that the data does not match the location information database (No in S130), it determines that the communication is from a spoofed destination (S150). Based on the comparison result, the control circuit 222 determines whether the destination of the received data is the correct destination or a spoofed destination.

[0167] Next, the control circuit 222 outputs the determination result (S160). The control circuit 222 may output the determination result to a higher-level system via the CAN interface 223, for example. If the control circuit 222 determines Yes in step S140, it may store data from the device in the memory circuit 224 and control the battery pack 10 based on the data. If the control circuit 222 determines No in step S140, it may stop or ignore (e.g., discard) the data from the device and not control the battery pack 10 based on the data (e.g., prohibit control of the battery pack 10 based on the data). If the control circuit 222 determines that the terminal device 6 is an unauthorized device, it disables communication with the terminal device 6.

[0168] Such a BMS 5c can improve the security performance of the vehicle 1. For example, it is possible to protect the vehicle 1 from cyber attacks.

[0169] The location information database used for the determination may be a database including distances measured by the BMS according to the second embodiment or the modification of the second embodiment. For example, the process shown in Fig. 16 may be executed after the operation shown in Fig. 7. For example, the control circuit 222 controls each component to measure the TOF by IR-UWB communication after pairing by the other wireless communication units of the monitoring circuit 100 and the management circuit 200.

[0170] (Other Embodiments) While the battery management system 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 embodiments constructed by combining components of different embodiments may also be included in the present disclosure.

[0171] In the above-described embodiment, an example has been described in which the identification information of the monitoring circuit 100 is transmitted to the management circuit 200 by BLE communication, but for example, the identification information may be transmitted to the management circuit 200 by IR-UWB communication. In other words, data may also be transmitted from the monitoring circuit 100 to the management circuit 200 by IR-UWB communication.

[0172] In the modification of the second embodiment, each of the plurality of monitoring circuits and the management circuit may include three or more communication antennas for IR-UWB communication.

[0173] In the second embodiment and the modified example of the second embodiment, at least one of the plurality of monitoring circuits and the management circuit may include a measurement circuit for measuring TOF.

[0174] In 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.

[0175] 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.

[0176] 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.

[0177] Furthermore, each of the monitoring circuit and management circuit according to the above embodiments and the like may be realized as a single device or may be realized by multiple devices. When at least one of the monitoring circuit and management circuit is realized by multiple devices, the components of the at least one circuit may be distributed in any manner among the multiple devices. When at least one of the circuits 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.

[0178] Furthermore, each component described in 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. Here, the term "LSI" is used, but depending on the level of integration, it may also be referred to as an IC, system LSI, super LSI, or ultra LSI. Furthermore, the integrated circuit implementation method is not limited to LSI, and may be implemented using a dedicated circuit (a general-purpose circuit that executes a dedicated program) or a general-purpose processor. After LSI fabrication, a field programmable gate array (FPGA) that can be programmed or a reconfigurable processor that can reconfigure the connections or settings of circuit cells within the LSI may also be used. Furthermore, if an integrated circuit technology that replaces LSI emerges due to advances in semiconductor technology or a derivative technology, that technology may naturally be used to integrate the components.

[0179] A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple processing units on a single chip. Specifically, it is a computer system that includes a microprocessor, ROM (Read Only Memory), RAM (Random Access Memory), etc. Computer programs are stored in the ROM. The system LSI achieves its functions when the microprocessor operates in accordance with the computer program.

[0180] 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 control method shown in FIG. 7 or FIG. 16 .

[0181] 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.

[0182] (Additional Note) The above description of the embodiments and the like discloses the following techniques.

[0183] (Technology 1) A battery management system for managing an assembled battery includes a plurality of monitoring circuits that monitor the assembled battery, and a management circuit that is connected to each of the plurality of monitoring circuits via wireless communication and manages the assembled battery, wherein each of the plurality of monitoring circuits and at least one of the management circuits has a measurement circuit that measures TOF (Time of Flight) between the monitoring circuit and the management circuit via IR-UWB (Impulse Response Ultra Wide Band) communication.

[0184] This allows the distances between the multiple monitoring circuits and the management circuit to be calculated by measuring the TOFs between the multiple monitoring circuits and the management circuit. For example, the locations of the multiple management circuits can be automatically identified based on the calculated distances. Therefore, the battery management system can further improve the ease of obtaining the locations of the multiple management circuits.

[0185] (Technology 2) The battery management system according to Technology 1 further includes a memory circuit that stores a first table linking the positions at which the plurality of monitoring circuits are disposed and the distances between the management circuits with position information indicating the relative relationships between the positions at which the plurality of monitoring circuits are disposed, and a control circuit that creates a second table linking identification information of the plurality of monitoring circuits with the position information based on the distances between the plurality of monitoring circuits and the management circuits acquired by the TOF measurement using the IR-UWB communication and the first table.

[0186] This makes it possible to easily create the second table using the distance based on TOF and the first table.

[0187] (Technology 3) The battery management system according to Technology 2, wherein the management circuit includes a plurality of communication antennas for the IR-UWB communication.

[0188] This makes it possible to calculate the relative angle between the management circuit and the monitoring circuit using trigonometry. In other words, even if there are two or more monitoring circuits at the same distance from the management circuit, it is possible to identify the respective locations of the two or more monitoring circuits.

[0189] (Technology 4) In the battery management system described in Technology 3, the control circuit creates the second table based on the distance between each of the plurality of monitoring circuits and the management circuit, and the relative angle between each of the plurality of monitoring circuits and the management circuit, which are obtained using each of the plurality of communication antennas.

[0190] As a result, even if there are two or more monitoring circuits at the same distance from the management circuit, it is possible to identify the respective locations of the two or more monitoring circuits.

[0191] (Technology 5) A battery management system according to any one of Technologies 2 to 4, wherein each of the plurality of monitoring circuits and the management circuit has a UWB communication unit that performs the IR-UWB communication and another wireless communication unit that performs communication different from the IR-UWB communication, and the identification information of each of the plurality of monitoring circuits is identification information used in communication by the other wireless communication unit in the monitoring circuit.

[0192] This allows the use of identification information used for communication in other wireless communication units, i.e., communication other than IR-UWB communication, so there is no need to set dedicated identification information, and the amount of processing in the battery management system can be reduced.

[0193] (Technology 6) The battery management system according to Technology 5, wherein the identification information is a MAC address.

[0194] This allows the MAC address to be used as identification information. Because a MAC address is uniquely assigned to each monitoring circuit, it is easy to identify multiple monitoring circuits.

[0195] (Technology 7) The battery management system according to any one of Technologies 1 to 6, wherein the plurality of monitoring circuits are arranged so that the distances to the management circuit are different from each other.

[0196] This makes it possible to identify the location of the monitoring circuit simply by calculating the distance between the monitoring circuit and the management circuit.

[0197] (Technology 8) A battery management system for managing an assembled battery, comprising: a monitoring circuit that monitors the assembled battery; a management circuit that is connected to the monitoring circuit via IR-UWB communication and manages the assembled battery; a memory circuit that stores a table including a distance between the monitoring circuit and the management circuit; a measurement circuit that measures TOF (Time of Flight) between the management circuit and a terminal device that is a communication source via the IR-UWB communication; and a control circuit that detects whether the terminal device is an unauthorized device based on information based on the TOF measured by the measurement circuit and the table.

[0198] This makes it possible to determine whether a terminal device is an unauthorized device by using the distance between the management circuit and the terminal device acquired through IR-UWB communication. For example, it is possible to detect if an unauthorized terminal device is communicating with the management circuit by masquerading as a monitoring circuit. Therefore, the battery management system can achieve further improvements in terms of improving security performance.

[0199] (Technology 9) In the battery management system according to Technology 8, the control circuit disables communication with the terminal device when determining that the terminal device is an unauthorized device.

[0200] This makes it possible to prevent the management circuit from controlling the battery pack based on information from an unauthorized terminal device.

[0201] (Technology 10) A battery management system according to Technology 8 or 9, wherein each of the monitoring circuit and the management circuit has a UWB communication unit that performs the IR-UWB communication and another wireless communication unit that performs communication different from the IR-UWB communication, and the table includes information linking information based on the TOF with identification information used for communication in the other wireless communication unit.

[0202] This makes it possible to improve the security performance of the BMS by using a table that uses identification information used in communication by other wireless communication units, that is, in communication other than IR-UWB communication.

[0203] (Technology 11) The battery management system according to Technology 10, wherein the control circuit controls the monitoring circuit and the management circuit to measure the TOF by the IR-UWB communication after pairing by the other wireless communication unit.

[0204] This allows the management circuit to acquire the identification information of the monitoring circuit before TOF measurement. For example, when creating a table that associates the relative position of the monitoring circuit with the identification information, the table can be easily created.

[0205] (Technology 12) The battery management system according to any one of Technologies 1 to 11, further comprising the assembled battery.

[0206] This allows further improvements to be made in battery management systems equipped with assembled batteries.

[0207] The present disclosure is useful for battery management systems mounted on vehicles.

[0208] REFERENCE SIGNS LIST 1 vehicle 2 seat 3 chassis 4 junction box 5, 5a, 5b, 5c battery management system (BMS) 6 terminal device 7 shunt resistor 8 relay 9 motor 10 assembled battery 11 battery pack 11a battery cell 100, 100b, 101, 101b, 102, 102b, 103, 103b, 104, 104b, 105, 105b, 106, 106b, 107, 107b, 108, 108b monitoring circuit 110 battery monitoring unit 111 voltage detection circuit 112 temperature measurement circuit 113 abnormality diagnosis circuit 114 voltage measurement circuit 115, 121, 213, 221 communication interface 120, 210 wireless communication unit 122, 212, 222 control circuit 123 BLE communication circuit (second wireless communication circuit) 124, 215 Measurement circuit 125 IR-UWB communication circuit (first wireless communication circuit) 130 Communication antenna (second communication antenna) 140 Communication antenna (first communication antenna) 150, 250 Communication antenna 200, 200b Management circuit 211 BLE communication circuit (fourth wireless communication circuit) 214 IR-UWB communication circuit (third wireless communication circuit) 220 MCU 223 CAN interface 224 Memory circuit 230 Communication antenna (fourth communication antenna) 240 Communication antenna (third communication antenna) 260 Current measurement circuit 270 Communication circuit

Claims

1. A battery management system for managing an assembled battery, comprising: a plurality of monitoring circuits for monitoring the assembled battery; and a management circuit connected to each of the plurality of monitoring circuits via wireless communication and for managing the assembled battery, wherein each of the plurality of monitoring circuits and at least one of the management circuits has a measurement circuit for measuring TOF (Time of Flight) between the monitoring circuit and the management circuit via IR-UWB (Impulse Response Ultra Wide Band) communication.

2. The battery management system of claim 1, further comprising: a memory circuit that stores a first table linking the positions at which the multiple monitoring circuits are arranged and the distance between the management circuits with position information indicating the relative relationship of the positions at which the multiple monitoring circuits are arranged; and a control circuit that creates a second table linking identification information of each of the multiple monitoring circuits with the position information based on the first table and the distance between each of the multiple monitoring circuits and the management circuit obtained by TOF measurement using the IR-UWB communication.

3. The battery management system according to claim 2, wherein the management circuit is provided with a plurality of communication antennas for the IR-UWB communication.

4. The battery management system of claim 3, wherein the control circuit creates the second table based on the distance between each of the plurality of monitoring circuits and the management circuit, and the relative angle between each of the plurality of monitoring circuits and the management circuit, obtained using each of the plurality of communication antennas.

5. A battery management system as described in any one of claims 2 to 4, wherein each of the plurality of monitoring circuits and the management circuit has a UWB communication unit that performs the IR-UWB communication and another wireless communication unit that performs communication different from the IR-UWB communication, and identification information of each of the plurality of monitoring circuits is identification information used for communication in the other wireless communication unit in the monitoring circuit.

6. The battery management system according to claim 5, wherein the identification information is a MAC address.

7. The battery management system according to any one of claims 1 to 4, wherein the plurality of monitoring circuits are arranged so that their distances to the management circuit are different from each other.

8. A battery management system for managing a battery pack, comprising: a monitoring circuit for monitoring the battery pack; a management circuit connected to the monitoring circuit via IR-UWB communication and managing the battery pack; a memory circuit for storing a table including a distance between the monitoring circuit and the management circuit; a measurement circuit for measuring a TOF (Time of Flight) between the management circuit and a terminal device that is a communication source via the IR-UWB communication; and a control circuit for detecting whether the terminal device is an unauthorized device based on information based on the TOF measured by the measurement circuit and the table.

9. The battery management system according to claim 8, wherein the control circuit disables communication with the terminal device when the control circuit determines that the terminal device is an unauthorized device.

10. A battery management system as described in claim 8 or 9, wherein each of the monitoring circuit and the management circuit has a UWB communication unit that performs the IR-UWB communication and another wireless communication unit that performs communication different from the IR-UWB communication, and the table includes information linking information based on the TOF with identification information used for communication in the other wireless communication unit.

11. The battery management system according to claim 10, wherein the control circuit controls to measure the TOF by the IR-UWB communication after pairing between the monitoring circuit and the management circuit by the other wireless communication unit.

12. The battery management system according to any one of claims 1 to 4, 8 and 9, further comprising the assembled battery.

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