surveillance system

Abstract

To provide a monitoring system capable of reducing power consumption, in a non-operating state of a monitored apparatus, of a control device that periodically communicates with a monitoring device, in an operating state of the monitored apparatus.SOLUTION: In a non-operating state of a battery pack 20 as a monitored apparatus, a communication connection in which at least one of a plurality of monitoring devices 30 serves as a communication master unit and the other monitoring devices 30 serve as communication slave units for the communication master unit is formed among the plurality of monitoring devices 30. On the other hand, the control device 40 is configured so as not to serve as a communication master unit for the plurality of monitoring devices 30, in a non-operating state of the monitored apparatus. Consequently, in the non-operating state of the battery pack 20, power consumption of the control device 40 can be reduced.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a monitoring system for monitoring a monitored device such as a battery pack. [Background technology]

[0002] For example, Patent Document 1 describes a battery control system that includes a plurality of battery cell management devices that are provided corresponding to each of a plurality of battery cell groups and that each acquire measurement results related to the state of charge of the battery cells in the corresponding battery cell group, and an assembled battery management device that performs wireless communication between the plurality of battery cell management devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6093448 Summary of the Invention [Problem to be solved by the invention]

[0004] In a monitoring system that uses multiple monitoring devices to monitor monitored equipment, such as the battery control system described above, when the monitored equipment is in a non-operating state, if communication is carried out between the control device and the multiple monitoring devices in the same way as when the monitored equipment is in an operating state, the large amount of power consumption in the control device can become a problem.

[0005] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a monitoring system that can reduce the power consumption of a control device when a monitored device is in an inactive state. [Means for solving the problem]

[0006] In order to achieve the above object, the monitoring system according to the present disclosure comprises: a plurality of monitoring devices (30) provided in the monitored devices and monitoring the monitored devices; a control device (40) that communicates wirelessly with a plurality of monitoring devices and acquires monitoring information of monitored devices from the plurality of monitoring devices; The monitored device is switched between an active and inactive state, When the monitored device is in an inoperative state, a communication connection is formed between the plurality of monitoring devices, in which at least one of the plurality of monitoring devices serves as a communication master and the other monitoring devices serve as communication slaves for the communication master; the plurality of monitoring devices periodically communicate with each other via the established communication connection; The control device is configured not to function as a communication master for the plurality of monitoring devices when the monitored device is in an inoperative state.

[0007] As described above, when the monitored equipment is in a non-operating state, a communication connection is formed between multiple monitoring devices, with at least one of the multiple monitoring devices acting as a communication master and the other monitoring devices acting as communication slaves to that communication master. When the monitored device is in an inactive state, the multiple monitoring devices periodically communicate with each other via the established communication connection. On the other hand, the control device is configured not to function as a communication master for multiple monitoring devices when the monitored devices are not in operation, thereby reducing the power consumption of the control device when the monitored devices are not in operation.

[0008] The reference numbers in parentheses above merely indicate an example of the correspondence with specific configurations in the embodiments described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0009] Furthermore, the technical features described in each claim in addition to the features described above will become clear from the description of the embodiments below and the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a vehicle equipped with a battery pack. [Figure 2] FIG. 2 is a perspective view showing a schematic configuration of a battery pack. [Figure 3] FIG. 2 is a plan view showing the battery pack. [Figure 4] FIG. 2 is a block diagram showing the configuration of a battery management system. [Figure 5] FIG. 2 is a diagram showing a communication sequence between a monitoring device and a control device. [Figure 6] FIG. 10 is a diagram illustrating a connection process. [Figure 7] FIG. 10 is a diagram illustrating a periodic communication process. [Figure 8] (a) is a diagram showing the communication form between the control device and multiple monitoring devices when the battery pack is in an operating state, and (b) is a diagram showing the communication form between the control device and multiple monitoring devices when the battery pack is in a non-operating state, in accordance with the first embodiment. [Figure 9] 4 is a flowchart showing the processing in the control device and each monitoring device according to the first embodiment. [Figure 10] FIG. 10 is a diagram showing a communication configuration between a control device and a plurality of monitoring devices when the battery pack is in a non-operating state according to a second embodiment. [Figure 11] 10 is a flowchart showing the processing in the control device and each monitoring device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0012] (First embodiment) First, the configuration of a vehicle equipped with a battery management system as a monitoring system according to this embodiment, particularly a vehicle related to a battery pack equipped with the battery management system, will be described with reference to Fig. 1. Fig. 1 is a diagram showing a schematic configuration of a vehicle. The vehicle is an electric vehicle such as an electric vehicle (BEV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). The battery management system can also be applied to moving objects other than vehicles, such as aircraft such as drones, ships, construction machinery, and agricultural machinery. The battery management system can also be applied to stationary batteries (storage batteries) for home or commercial use.

[0013] <Vehicle> As shown in Fig. 1, a vehicle 10 includes a battery pack (BAT) 11, a PCU 12, an MG 13, and an ECU 14. PCU is an abbreviation for Power Control Unit, MG is an abbreviation for Motor Generator, and ECU is an abbreviation for Electronic Control Unit.

[0014] The battery pack 11 includes a battery pack 20, which will be described later, and provides a chargeable and dischargeable DC voltage source. The battery pack 11 supplies power to the electrical loads of the vehicle 10. For example, the battery pack 11 supplies power to the MG 13 through the PCU 12. The battery pack 11 is charged through the PCU 12. The battery pack 11 is sometimes referred to as a main battery.

[0015] 1, the battery pack 11 is disposed in the front compartment of the vehicle 10. The battery pack 11 may also be disposed in the rear compartment, under the seat, under the floor, etc. For example, in the case of a hybrid vehicle, the compartment in which the engine is disposed may be referred to as the engine compartment, engine room, etc.

[0016] The temperature of the battery pack 11 is regulated by the wind generated when the vehicle 10 is running or by cooling air supplied from a fan mounted on the vehicle 10. The temperature of the battery pack 11 may also be regulated by a cooling liquid circulating inside the vehicle 10. The temperature regulation described above suppresses excessive temperature changes in the battery pack 11. Note that the battery pack 11 may simply be connected to a member with a large heat capacity, such as the body of the vehicle 10, in a manner that allows thermal conduction.

[0017] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the MG 13 in accordance with a control signal from the ECU 14. The PCU 12 is sometimes referred to as a power converter. The PCU 12 may include an inverter and a converter. The converter is disposed in a current path between the battery pack 11 and the inverter. The converter has a function of stepping up and down a DC voltage. The inverter converts the DC voltage stepped up by the converter into an AC voltage, for example, a three-phase AC voltage, and outputs it to the MG 13. The inverter converts the power generated by the MG 13 into a DC voltage and outputs it to the converter. The converter charges the battery pack 20 of the battery pack 11 with the DC voltage obtained by stepping down the DC voltage output from the inverter.

[0018] The MG 13 is an AC rotating electric machine, for example, a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The MG 13 functions as a drive source for the vehicle 10, i.e., as an electric motor. The MG 13 is driven by the PCU 12 to generate rotational driving force. The driving force generated by the MG 13 is transmitted to the drive wheels. The MG 13 functions as a generator when the vehicle 10 is braked, and performs regenerative power generation. The power generated by the MG 13 is supplied to the battery pack 11 via the PCU 12 and stored in the battery pack 20 in the battery pack 11.

[0019] The ECU 14 includes a computer equipped with a processor, memory, an input / output interface, and a bus connecting these components. The processor is hardware for performing arithmetic processing. The processor includes, for example, a CPU as a core. CPU is an abbreviation for Central Processing Unit. The memory is a non-transient, tangible storage medium that non-temporarily stores computer-readable programs, data, and the like. The memory stores various programs executed by the processor.

[0020] The ECU 14 acquires information about the battery pack 20 from the battery pack 11, for example, and controls the PCU 12 to control the driving of the MG 13 and the charging and discharging of the battery pack 11. The ECU 14 may acquire information about the voltage, temperature, current, SOC, SOH, etc. of the battery pack 20 from the battery pack 11. The ECU 14 may acquire battery information such as the voltage, temperature, and current of the battery pack 20 to calculate the SOC and SOH. SOC is an abbreviation for State Of Charge. SOH is an abbreviation for State Of Health.

[0021] The processor of the ECU 14 executes a plurality of instructions contained in a PCU control program stored in a memory, for example. In this way, the ECU 14 configures a plurality of functional units for controlling the PCU 12. In this way, the program stored in the memory causes the processor to execute a plurality of instructions, thereby configuring a plurality of functional units. The ECU 14 is sometimes referred to as an EVECU.

[0022] <Battery pack> Next, an example of the configuration of the battery pack 11 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a perspective view schematically showing the inside of the battery pack 11. In Fig. 2, the housing is indicated by a two-dot chain line. Fig. 3 is a plan view showing the top surface of each battery stack.

[0023] As shown in FIG. 2, the battery pack 11 includes a battery pack 20, a plurality of monitoring devices 30, a control device 40, and a housing 50. Hereinafter, of the surfaces of the housing 50, which is a substantially rectangular parallelepiped, the longitudinal direction of the surface on which the battery pack 11 is mounted on the vehicle 10 is referred to as the X direction, and the lateral direction of the surface is referred to as the Y direction. In FIG. 2, the bottom surface is the mounting surface. The up-down direction perpendicular to the mounting surface is referred to as the Z direction. The X direction, Y direction, and Z direction are orthogonal to one another. In this embodiment, the left-right direction of the vehicle 10 corresponds to the X direction, the front-rear direction corresponds to the Y direction, and the up-down direction corresponds to the Z direction. The arrangements shown in FIGS. 2 and 3 are merely examples, and the battery pack 11 may be arranged in any manner relative to the vehicle 10.

[0024] The battery pack 20 has a plurality of battery stacks 21 arranged side by side in the X direction. The battery stacks 21 may also be referred to as battery blocks, battery modules, etc. The battery pack 20 is configured by connecting a plurality of battery stacks 21 in series and / or parallel. In this embodiment, the plurality of battery stacks 21 are connected in series.

[0025] Each battery stack 21 has a plurality of battery cells 22. The plurality of battery cells 22 are housed in a case (not shown). This fixes the relative positions of the plurality of battery cells 22. The case is made of metal or resin. If the case is made of metal, an electrically insulating member may be interposed partially or entirely between the wall of the case and the battery cells 22.

[0026] The form of the fixing member is not particularly limited as long as it can fix the relative positions of the multiple battery cells 22. For example, a configuration in which the multiple battery cells 22 are restrained by a strip-shaped band may be employed. In this case, separators may be interposed between the multiple battery cells 22 to maintain a distance between them.

[0027] The battery stack 21 has a plurality of battery cells 22 connected in series. The battery stack 21 of this embodiment is configured by connecting a plurality of battery cells 22 arranged side by side in the Y direction in series. The assembled battery 20 provides the DC voltage source. The assembled battery 20, the battery stack 21, and the battery cells 22 correspond to a battery.

[0028] The battery cell 22 is a secondary battery that generates an electromotive force through a chemical reaction. The secondary battery may be a lithium-ion secondary battery, a nickel-metal hydride secondary battery, an organic radical battery, or the like. A lithium-ion secondary battery is a secondary battery that uses lithium as a charge carrier. Secondary batteries that can be used for the battery cell 22 include not only secondary batteries with liquid electrolytes, but also so-called all-solid-state batteries that use solid electrolytes.

[0029] Each battery cell 22 has a power generating element and a battery case that houses the power generating element. As shown in Fig. 3, the battery case of each battery cell 22 is formed in a flat shape. The battery case has a total of four side faces: two end faces aligned in the Z direction, two aligned in the X direction, and two aligned in the Y direction. The battery case of this embodiment is made of metal.

[0030] The battery cells 22 are stacked so that the side surfaces of the battery cases are in contact with each other in the Y direction. Each battery cell 22 has a positive terminal 25 and a negative terminal 26 at both ends in the X direction that protrude in the Z direction, more specifically in the Z+ direction indicating upward. The Z-direction positions of the protruding end faces of these positive terminals 25 and negative terminals 26 are the same for each battery cell 22. The battery cells 22 are stacked so that the positive terminals 25 and negative terminals 26 are alternately arranged in the Y direction.

[0031] Linear busbar units 23 are arranged on both ends in the X direction on the top surface of each battery stack 21. The busbar units 23 are arranged on both ends in the X direction of the protruding end faces of the positive electrode terminals 25 and negative electrode terminals 26 of the multiple battery cases. In other words, a pair of busbar units 23 are arranged in each battery stack 21.

[0032] Each busbar unit 23 has a plurality of busbars 24 that electrically connect positive terminals 25 and negative terminals 26 that are alternately arranged in the Y direction, and a busbar cover 27 that covers the plurality of busbars 24. The busbars 24 are plates made of a metal with good conductivity, such as copper or aluminum. The busbars 24 electrically connect the positive terminals 25 and negative terminals 26 of battery cells 22 that are adjacent to each other in the Y direction. As a result, in each battery stack 21, the plurality of battery cells 22 are connected in series.

[0033] With this connection structure, one of the two battery cells 22 located at the ends of the multiple battery cells 22 aligned in the Y direction in each battery stack 21 has the highest potential, and the other has the lowest potential. A predetermined wire is connected to at least one of the positive electrode terminal 25 of the battery cell 22 with the highest potential and the negative electrode terminal 26 of the battery cell 22 with the lowest potential.

[0034] 2, the multiple battery stacks 21 are aligned in the X direction. In one of two battery stacks 21 adjacent to each other in the X direction, the positive electrode terminal 25 of the battery cell 22 with the highest potential is connected to the negative electrode terminal 26 of the battery cell 22 with the lowest potential in the other battery stack 21 via a predetermined wiring. In this way, the multiple battery stacks 21 are connected in series.

[0035] With this connection structure, one of the two battery stacks 21 located at the ends of the multiple battery stacks 21 lined up in the X direction becomes the highest potential side, and the other becomes the lowest potential side. In the battery stack 21 on the highest potential side, an output terminal is connected to the positive electrode terminal 25 of the battery cell 22 with the highest potential among the multiple battery cells 22. In the battery stack 21 on the lowest potential side, an output terminal is connected to the negative electrode terminal 26 of the battery cell 22 with the lowest potential among the multiple battery cells 22. These two output terminals are connected to electrical equipment installed in the vehicle 10, such as the PCU 12.

[0036] Two battery stacks 21 adjacent to each other in the X direction do not necessarily have to be electrically connected via a predetermined wiring. Any two of the battery stacks 21 arranged in the X direction may be electrically connected via a predetermined wiring. Furthermore, the positions in the Y direction of the positive electrode terminal 25 and the negative electrode terminal 26 electrically connected via a predetermined wiring may be equal or different. That is, the positive electrode terminal 25 and the negative electrode terminal 26 may at least partially face each other in the X direction, or may not face each other at all. At least a portion of one of the positive electrode terminal 25 and the negative electrode terminal 26 may be located in the projection area of ​​the other in the X direction, or may not be located at all.

[0037] The bus bar cover 27 is made of an electrically insulating material such as resin. The bus bar cover 27 is provided linearly from one end of the battery stack 21 to the other end along the Y direction so as to cover the multiple bus bars 24. The bus bar cover 27 may have a partition wall. The partition wall improves the insulation between two bus bars 24 adjacent to each other in the Y direction.

[0038] The monitoring device 30 is provided individually for each of the plurality of battery stacks 21. As shown in FIG. 2 , the monitoring device 30 is disposed between a pair of busbar units 23 in each battery stack 21. The monitoring device 30 faces the protruding end faces of the positive electrode terminal 25 and the negative electrode terminal 26 of the battery case in the Z direction. The monitoring device 30 and these end faces may be spaced apart in the Z direction, or may face each other and be in contact with each other in the Z direction. An intervening object such as an insulating sheet may be provided between the monitoring device 30 and these end faces.

[0039] The monitoring device 30 is fixed to the busbar unit 23 with screws or the like. As will be described later, the monitoring device 30 is configured to be able to communicate wirelessly with the control device 40. An antenna 37 (described later) provided in the monitoring device 30 is arranged so as not to overlap with the busbar unit 23 in the Z direction, that is, so as to protrude further than the busbar unit 23 in the Z direction.

[0040] To avoid interference with wireless communication, a non-magnetic material may be used as the material for connecting members such as screws that connect the monitoring device 30 and the busbar unit 23. In addition to the screws, non-magnetic materials may also be used as the constituent materials for components that do not necessarily need to be magnetic, among the components provided in the battery stack 21.

[0041] In this embodiment, the multiple monitoring devices 30 are lined up in the X direction. The positions of the multiple monitoring devices 30 in the Y direction are the same. Due to the configuration described above, the distance between the multiple monitoring devices 30 is prevented from increasing.

[0042] The control device 40 is attached to the outer surface of the battery stack 21 located at one end in the X direction. The control device 40 is configured to be able to wirelessly communicate with each monitoring device 30. An antenna 42 (described later) provided in the control device 40 is disposed at approximately the same height in the Z direction as the antenna 37 of the monitoring device 30. In other words, the antenna 42 of the control device 40 is disposed so as to protrude further than the busbar unit 23 in the Z direction.

[0043] In the battery pack 11, the monitoring device 30 and the control device 40 provide a battery management system 60, which will be described later.

[0044] To prevent the battery pack 11 from becoming a source of electromagnetic noise, it is necessary to prevent radio waves from leaking outside the space in which wireless communication is performed between the monitoring device 30 and the control device 40. Conversely, to prevent this wireless communication from being obstructed, it is necessary to prevent electromagnetic noise from entering the communication space.

[0045] For this reason, the housing 50 has the ability to reflect electromagnetic waves, for example. The housing 50 is provided with the following materials, examples of which are shown below, in order to reflect electromagnetic waves. For example, the housing 50 is provided with a magnetic material such as metal. The housing 50 is provided with a resin material and a magnetic material covering the surface. The housing 50 is provided with a resin material and a magnetic material embedded inside the resin material. The housing 50 is provided with carbon fiber. The housing 50 may have the ability to absorb electromagnetic waves instead of the ability to reflect electromagnetic waves.

[0046] The housing 50 may have a hole that communicates with the storage space inside and the space outside (external space). The hole is defined by a connecting surface between the inner and outer surfaces of the housing 50. This hole is used for ventilation, for extracting power lines, for extracting signal lines, etc. In the case of a configuration with a hole, a cover may be provided for the hole. The cover prevents communication between the storage space and the external space. The cover may cover the entire hole, or may cover only a portion of the hole.

[0047] The cover portion is provided, for example, on any one of the inner surface, outer surface, and connecting surface of the housing 50. The cover portion may be disposed opposite the hole in a manner that covers the hole without being provided on any of the inner surface, outer surface, and connecting surface. When the cover portion and the hole are spaced apart, the distance between them is shorter than the length of the hole. The length of the hole is either the distance between the inner surface and the outer surface or the distance in a direction perpendicular to this distance.

[0048] The covering portion is, for example, a connector, an electromagnetic shielding member, a sealing material, etc. The covering portion comprises the following materials, as examples: The covering portion comprises a magnetic material, such as metal; The covering portion comprises a resin material and a magnetic material covering the surface of the resin material; The covering portion comprises a resin material and a magnetic material embedded inside the resin material; The covering portion comprises carbon fiber; The covering portion includes a resin material.

[0049] The hole in the housing 50 may be covered by at least one of the elements housed in the housing space of the housing 50. The distance between this housed object and the hole is shorter than the length of the hole. Furthermore, power lines and signal lines may be arranged across the housing space and the external space while being held by an electrically insulating member that forms part of the wall of the housing 50.

[0050] <Battery management system> Next, a schematic configuration of the battery management system will be described with reference to Fig. 4. Fig. 4 is a block diagram showing the configuration of the battery management system.

[0051] As shown in Fig. 4, the battery management system 60 includes multiple monitoring devices (SBMs) 30 and a control device (ECU) 40. Hereinafter, the monitoring devices may be referred to as SBMs. The control devices 40 may be referred to as battery ECUs, BMUs, etc. BMU is an abbreviation for Battery Management Unit. The battery management system 60 is a system that manages batteries using wireless communication. This wireless communication uses a frequency band used for short-range communication, such as the 2.4 GHz band or the 5 GHz band.

[0052] The battery management system 60 employs one-to-one communication or network communication depending on the number of nodes for wireless communication by the monitoring device 30 and / or the control device 40. The number of nodes may change depending on the hibernation state of the monitoring device 30 and / or the control device 40. When the number of nodes is two, the battery management system 60 employs one-to-one communication. When the number of nodes is three or more, the battery management system 60 employs network communication. One form of network communication is star communication, in which one node is designated as a master and the remaining nodes are designated as slaves, and wireless communication is performed between the master and all of the slaves. Another form of network communication is chain communication, in which multiple nodes are connected in series and wireless communication is performed.

[0053] The battery management system 60 further includes a sensor 70. The sensor 70 includes a physical quantity detection sensor that detects the physical quantity of each battery cell 22, a discrimination sensor, etc. The physical quantity detection sensor includes, for example, a voltage sensor, a temperature sensor, a current sensor, etc.

[0054] The voltage sensor includes detection wiring connected to the bus bar 24. The voltage sensor detects the voltage (cell voltage) of each of the plurality of battery cells 22. The discrimination sensor determines whether or not the correct battery is installed.

[0055] The temperature sensors are selectively provided in some of the plurality of battery cells 22 included in the battery stack 21. The temperature sensors detect the temperatures (cell temperatures) of the selected battery cells 22 as the temperature of the battery stack 21. Of the plurality of battery cells 22 included in one battery stack 21, the temperature sensors are provided in the battery cell 22 expected to have the highest temperature, the battery cell 22 expected to have the lowest temperature, the battery cell 22 expected to have an intermediate temperature, and the like. The number of temperature sensors for one battery stack 21 is not particularly limited.

[0056] A current sensor is provided in each of the plurality of battery stacks 21. The current sensor detects a current (cell current) that flows commonly through each of the plurality of series-connected battery cells 22 and the plurality of series-connected battery stacks 21. In this embodiment, all of the battery stacks 21 are connected in series, so one current sensor is provided, but the number of current sensors is not limited to this example.

[0057] <Monitoring device> First, the monitoring device 30 will be described. The configuration of each monitoring device 30 is the same. The monitoring device 30 includes a power supply circuit (PSC) 31, a multiplexer (MUX) 32, a monitoring IC (MIC) 33, a microcomputer (MC) 34, a wireless IC (WIC) 35, a front-end circuit (FE) 36, and an antenna (ANT) 37. Communication between the elements within the monitoring device 30 is performed via wires.

[0058] The power supply circuit 31 generates operating power for other circuit elements included in the monitoring device 30, using the voltage supplied from the battery stack 21. In this embodiment, the power supply circuit 31 includes power supply circuits 311, 312, and 313. The power supply circuit 311 generates a predetermined voltage using the voltage supplied from the battery stack 21 and supplies it to the monitoring IC 33. The power supply circuit 312 generates a predetermined voltage using the voltage generated by the power supply circuit 311 and supplies it to the microcomputer 34. The power supply circuit 313 generates a predetermined voltage using the voltage generated by the power supply circuit 311 and supplies it to the wireless IC 35.

[0059] The multiplexer 32 is a selection circuit that selects one of at least some of the detection signals of the multiple sensors 70 provided in the battery pack 11 and outputs the selected signal. The multiplexer 32 selects (switches) the input in accordance with a selection signal from the monitoring IC 33 and outputs it as one signal.

[0060] The monitoring IC 33 senses (acquires) battery information such as cell voltage and cell temperature and transmits it to the microcomputer 34. For example, the monitoring IC 33 acquires cell voltage directly from a voltage sensor and acquires information such as cell temperature through a multiplexer. The monitoring IC 33 acquires cell voltage by correlating it with which battery cell 22 the value belongs to. In other words, it acquires cell voltage while distinguishing between cells. The cell current detected by the current sensor may be input to the monitoring IC 33 or may be input to the control device 40 via a wired connection.

[0061] The monitoring IC 33 is sometimes referred to as a cell monitoring circuit (CSC). CSC is an abbreviation for Cell Supervising Circuit. The monitoring IC 33 performs fault diagnosis on the circuitry of the monitoring device 30, including itself. That is, the monitoring IC 33 transmits battery monitoring information, including battery information and fault diagnosis information, to the microcontroller 34. The monitoring device 30 may store (preserve) the acquired battery monitoring information in a memory such as the microcontroller 34. When the monitoring IC 33 receives data requesting acquisition of battery monitoring information from the microcontroller 34, it senses the battery information and transmits the battery monitoring information, including the battery information, to the microcontroller 34. In addition to the examples described above, the battery monitoring information may also include information such as exhaust gas temperature, impedance, cell voltage equalization status, stack voltage, synchronization status with the control device 40, and the presence or absence of abnormalities in the detection wiring.

[0062] The microcomputer 34 is a microcomputer equipped with a processor (CPU), memory (ROM and RAM), an input / output interface, and a bus connecting these. The CPU executes various programs stored in the ROM while utilizing the temporary storage function of the RAM, thereby constructing multiple functional units. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory.

[0063] The microcomputer 34 controls the schedule of sensing and self-diagnosis by the monitoring IC 33. The microcomputer 34 receives battery monitoring information transmitted from the monitoring IC 33 and transmits it to the wireless IC 35. The microcomputer 34 transmits data requesting acquisition of battery monitoring information to the monitoring IC 33. For example, upon receiving data requesting acquisition of battery monitoring information transmitted from the wireless IC 35, the microcomputer 34 may transmit data requesting acquisition of battery monitoring information to the monitoring IC 33. The microcomputer 34 may autonomously request acquisition of battery monitoring information from the monitoring IC 33. For example, the microcomputer 34 may periodically request acquisition of battery monitoring information from the monitoring IC 33. Furthermore, in order to collect battery monitoring information of other monitoring devices 30, the microcomputer 34 may request other monitoring devices 30 to acquire and transmit battery monitoring information via the wireless IC 35 or the like. The collected battery monitoring information of other monitoring devices 30 is stored in the memory of the microcomputer 34.

[0064] The wireless IC 35 includes an RF circuit and a microcomputer (not shown) to transmit and receive data wirelessly. The microcomputer includes a memory. The wireless IC 35 has a transmission function that modulates transmission data and oscillates at the frequency of an RF signal. The wireless IC 35 has a reception function that demodulates received data. RF is an abbreviation for radio frequency.

[0065] The wireless IC 35 modulates the data including the battery monitoring information transmitted from the microcomputer 34 and transmits it to other nodes such as the control device 40 via the front-end circuit 36 ​​and the antenna 37. The wireless IC 35 adds data necessary for wireless communication, such as communication control information, to the transmission data including the battery monitoring information and transmits it. The data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code. The wireless IC 35 controls the data size, communication format, schedule, error detection, etc. of wireless communication with other nodes.

[0066] The wireless IC 35 receives data transmitted from other nodes via the antenna 37 and the front-end circuit 36 ​​and demodulates the data. For example, when the wireless IC 35 receives data including a request to transmit battery monitoring information, it transmits the data including the battery monitoring information to other nodes in response to the request. In addition to the battery monitoring information described above, the monitoring device 30 may also transmit battery traceability information and / or manufacturing history information to other nodes. The battery traceability information may include, for example, the number of charge / discharge cycles, the number of failures, and the total charge / discharge time. The manufacturing history information may include, for example, the manufacturing date, location, manufacturer, serial number, and manufacturing number. The manufacturing history information is stored in a memory provided in the monitoring device 30. The monitoring device 30 may also transmit the battery traceability information and / or manufacturing history information to other nodes instead of the battery monitoring information described above.

[0067] The front-end circuit 36 ​​has a matching circuit for matching the impedance between the wireless IC 35 and the antenna 37, and a filter circuit for removing unnecessary frequency components.

[0068] The antenna 37 converts the electric signal into a radio wave and radiates it into space. The antenna 37 receives the radio wave propagating through space and converts it into an electric signal.

[0069] <Control device> Next, the control device 40 will be described with reference to Fig. 4. The control device 40 includes a power supply circuit (PSC) 41, an antenna (ANT) 42, a front-end circuit (FE) 43, a wireless IC (WIC) 44, a main microcomputer (MMC) 45, and a sub-microcomputer (SMC) 46. Communication between the elements within the control device 40 is performed via wires.

[0070] The power supply circuit 41 generates operating power for other circuit elements included in the control device 40, using voltage supplied from the battery (BAT) 15. The battery 15 is a DC voltage source separate from the battery pack 11 and mounted on the vehicle 10. The battery 15 is sometimes referred to as an auxiliary battery because it supplies power to auxiliary devices of the vehicle 10. In this embodiment, the power supply circuit 41 includes power supply circuits 411 and 412. The power supply circuit 411 generates a predetermined voltage using the voltage supplied from the battery 15 and supplies it to the main microcomputer 45 and the sub-microcomputer 46. To simplify the diagram, the electrical connection between the power supply circuit 411 and the sub-microcomputer 46 is omitted. The power supply circuit 412 generates a predetermined voltage using the voltage generated by the power supply circuit 411 and supplies it to the wireless IC 44.

[0071] The antenna 42 converts the electrical signal into a radio wave and radiates it into space. The antenna 42 receives the radio wave propagating through space and converts it into an electrical signal.

[0072] The front-end circuit 43 has a matching circuit for matching the impedance between the wireless IC 44 and the antenna 42, and a filter circuit for removing unnecessary frequency components.

[0073] The wireless IC 44 includes an RF circuit and a microcomputer (not shown) for wirelessly transmitting and receiving data. Like the wireless IC 35, the wireless IC 44 has transmitting and receiving functions. The wireless IC 44 receives and demodulates data transmitted from the monitoring device 30 via the antenna 42 and the front-end circuit 43. It then transmits the data, including battery monitoring information, to the main microcomputer 45. The wireless IC 44 receives and modulates the data transmitted from the main microcomputer 45, and transmits the data to the monitoring device 30 via the front-end circuit 43 and the antenna 42. The wireless IC 44 adds data necessary for wireless communication, such as communication control information, to the transmitted data and transmits it. The data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code. The wireless IC 44 controls the data size, communication format, schedule, error detection, and other aspects of wireless communication between other nodes.

[0074] The main microcomputer 45 is a microcomputer equipped with a CPU, ROM, RAM, an input / output interface, and buses connecting these. The ROM stores various programs executed by the CPU. The main microcomputer 45 generates commands requesting predetermined processing from the monitoring device 30 and transmits transmission data including the commands to the wireless IC 44. The main microcomputer 45 generates, for example, a command requesting the transmission of battery monitoring information. The main microcomputer 45 may generate commands requesting the acquisition of battery monitoring information as well as the transmission of battery monitoring information. Requests described in this specification are sometimes referred to as instructions.

[0075] The main microcomputer 45 receives data including the battery monitoring information transmitted from the wireless IC 44 and executes predetermined processing based on the battery monitoring information. In this embodiment, the main microcomputer 45 acquires cell currents from current sensors and executes predetermined processing based on the battery monitoring information and the acquired cell currents. For example, the main microcomputer 45 executes processing to transmit the acquired battery monitoring information to the ECU 14. The main microcomputer 45 may calculate at least one of the internal resistance, open circuit voltage (OCV), SOC, and SOH of the battery cells 22 based on the battery monitoring information and transmit information including the calculated data to the ECU 14. OCV stands for open circuit voltage.

[0076] The main microcomputer 45 performs a process of estimating the internal resistance and open-circuit voltage of the battery cell 22, for example, based on the cell voltage and cell current. The open-circuit voltage is the cell voltage according to the SOC of the battery cell 22. The open-circuit voltage is the cell voltage when no current is flowing. There is a difference between the open-circuit voltage and the cell voltage acquired by the monitoring device 30 due to a voltage drop according to the internal resistance and the cell current. The internal resistance changes according to the cell temperature. The lower the cell temperature, the larger the value of the internal resistance. The main microcomputer 45 performs a process of estimating the internal resistance and open-circuit voltage of the battery cell 22, for example, taking the cell temperature into account.

[0077] Based on the battery monitoring information, the main microcomputer 45 may instruct the execution of an equalization process to equalize the voltages of the battery cells 22. The main microcomputer 45 may acquire an IG signal from the vehicle 10 and execute the above-described process according to the driving state of the vehicle 10. Based on the battery monitoring information, the main microcomputer 45 may execute a process to detect abnormalities in the battery cells 22 or circuits, and may send abnormality detection information to the ECU 14.

[0078] The sub-microcomputer 46 is a microcomputer equipped with a CPU, ROM, RAM, an input / output interface, and a bus connecting these. The ROM stores various programs executed by the CPU. The sub-microcomputer 46 performs monitoring processing within the control device 40. For example, the sub-microcomputer 46 may monitor data between the wireless IC 44 and the main microcomputer 45. The sub-microcomputer 46 may monitor the status of the main microcomputer 45. The sub-microcomputer 46 may monitor the status of the wireless IC 44.

[0079] <Communication during operation> The battery management system 60 of this embodiment performs star-type network communication when the battery pack 20 is in an operating state, supplying power from the battery pack 20 to on-board systems such as the MG 13 via a system main relay (SMR) (not shown). That is, the control device 40 performs wireless communication with each of the multiple monitoring devices 30 via a communication connection established individually with the multiple monitoring devices 30. For convenience, the following describes wireless communication between one monitoring device 30 and the control device 40, but the control device 40 performs similar processing with all of the monitoring devices 30. Note that the communication format between the control device 40 and the multiple monitoring devices 30 when the battery pack 20 is in an operating state is not limited to star-type network communication, and may be chain-type network communication.

[0080] First, a connection process for establishing an individual communication connection between the monitoring device 30 and the control device 40 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing a communication sequence between the monitoring device 30 and the control device 40. The communication sequence is sometimes referred to as a communication flow. Fig. 6 shows an example of the connection process. In Fig. 5 and Fig. 6, the control device 40 is represented as ECU 40.

[0081] As shown in FIG. 5, a connection process (S10) is performed between the control device 40 and each monitoring device 30 to individually establish a communication connection with each of the multiple monitoring devices 30, with the control device 40 acting as a communication master and each monitoring device 30 acting as a communication slave. When the control device 40 and each monitoring device 30 communicate according to the BLE communication protocol, this connection process (S10) includes a connection establishment process (S11) and a pairing process (S12), as shown in FIG. 6. BLE is an abbreviation for Bluetooth Low Energy. Bluetooth is a registered trademark. However, communication between the control device 40 and each monitoring device 30 may be performed according to a communication protocol other than the BLE communication protocol.

[0082] In the connection establishment process (S11), the control device 40 executes a scanning operation (S111), and the monitoring device 30 executes an advertising operation (S112). The scanning operation may start earlier than the advertising operation, at approximately the same timing, or later than the advertising operation.

[0083] The wireless IC 35 of the monitoring device 30 performs an advertising operation to notify the control device 40 of its own existence, and transmits an advertisement packet (ADV_PKT) to the wireless IC 44 of the control device 40. The advertisement packet includes ID information of the monitoring device 30 itself and the control device 40.

[0084] When the control device 40 detects an advertisement packet, that is, a monitoring device 30, by the scanning operation, it transmits a connection request (CONNECT_REQ) to the detected monitoring device 30 (S113).

[0085] When the monitoring device 30 receives a connection request, a connection is established between one monitoring device 30 and the control device 40. Once the connection is established, the monitoring device 30 stops transmitting advertisement packets. The monitoring device 30 periodically transmits advertisement packets until the connection is established.

[0086] After the connection establishment process is completed, a pairing process (S12) is then executed. The pairing process is a process for performing encrypted data communication. The pairing process includes a process for exchanging unique information (S121). In this exchange process, unique information held by each device (for example, an encryption key or information for generating an encryption key) is exchanged and stored in each device's memory. After the process of step S121 is executed, encryption using the exchanged unique information becomes possible.

[0087] Although the example in which the control device 40 performs the scanning operation and the monitoring device 30 performs the advertising operation has been described, the present invention is not limited to this. A configuration in which the monitoring device 30 performs the scanning operation and the control device 40 performs the advertising operation may also be used.

[0088] Next, the periodic communication process performed between the monitoring device 30 and the control device 40 when the battery pack 20 is in operation will be described with reference to Figures 5 and 7. Figure 7 shows an example of the periodic communication process. In Figure 7, the monitoring IC 33 is represented as MIC33, the wireless IC 35 as WIC35, and the control device 40 as ECU40.

[0089] When the above-described connection process is completed, the monitoring device 30 and the control device 40 execute a periodic communication process (S20). In this periodic communication process, the control device 40 and the monitoring device 30 perform data communication periodically (periodically). In the data communication, as shown in FIG. 7, for example, the control device 40 transmits request data to the monitoring device 30 for which the connection process has been completed (S21). As an example, the control device 40 transmits request data including a request to acquire and a request to transmit battery monitoring information.

[0090] When the wireless IC 35 of the monitoring device 30 receives the request data, it transmits an acquisition request for the battery monitoring information, i.e., an acquisition instruction, to the monitoring IC 33 (S22). The wireless IC 35 of this embodiment transmits the acquisition request to the monitoring IC 33 via the microcomputer 34.

[0091] When the monitoring IC 33 receives the acquisition request, it performs sensing (S23). The monitoring IC 33 performs sensing and acquires battery information of each battery cell 22 through the multiplexer 32. The monitoring IC 33 also performs circuit fault diagnosis.

[0092] Next, the monitoring IC 33 transmits the acquired battery monitoring information to the wireless IC 35 (S24). In this embodiment, the battery monitoring information transmitted includes the failure diagnosis result along with the battery information. The monitoring IC 33 transmits the battery monitoring information to the wireless IC 35 via the microcomputer 34.

[0093] When the wireless IC 35 receives the battery monitoring information from the monitoring IC 33, it transmits transmission data including the battery monitoring information, i.e., response data, to the control device 40 (S25). The control device 40 receives the response data (S26). The control device 40 periodically performs the above-mentioned data communication with the monitoring device 30 with which a connection has been established.

[0094] Based on the received response data, i.e., the battery monitoring information, the control device 40 performs predetermined processing, i.e., as described above, processing to send the acquired battery monitoring information to the ECU 14, processing to instruct the execution of an equalization processing to equalize the voltage of each battery cell 22, processing to detect abnormalities in the battery cells 22 or circuit, etc. (S30).

[0095] Although the example has been described in which the monitoring device 30 acquires the battery monitoring information based on an acquisition request from the control device 40, the present invention is not limited to this. The monitoring device 30 may autonomously acquire the battery monitoring information and transmit the battery monitoring information it holds to the control device 40 based on a transmission request from the control device 40. This eliminates the need for the processing of steps S22 to S24 in response to the acquisition request.

[0096] <Communication during non-operational state> FIG. 8(a) shows an example of a communication configuration (i.e., a star network) when the battery pack 20 is in an operating state, in which the control device 40 acts as a communication master and individually communicates with multiple monitoring devices 30, which are communication slaves. For example, if the SMR is turned off when the ignition switch is turned off and the battery pack 20 is in an inoperable state and does not supply power to onboard systems such as the MG 13 connected via the SMR, maintaining the communication configuration shown in FIG. 8(a) would increase power consumption in the control device 40 and potentially accelerate battery depletion. This is mainly because the control device 40 must communicate with multiple monitoring devices 30, and the communication master function, which manages communication schedules, generally imposes a higher load than the communication slave function. Note that the battery pack 20 continues to supply power to devices such as the monitoring devices 30 directly connected to the battery pack 20 without going through the SMR, even when the battery pack 20 is in an inoperable state.

[0097] Therefore, when the battery pack 20 is in a non-operating state, the battery management system 60 according to this embodiment switches to a communication format different from that used when the battery pack 20 is in an operating state, thereby reducing power consumption of the control device 40. The communication format when the battery pack 20 is in a non-operating state will be described in detail below.

[0098] Fig. 8(b) is a diagram showing an example of a communication network when the battery pack 20 is in a non-operating state. As shown in Fig. 8(b), when the battery pack 20 is in a non-operating state, the control device 40 cuts off communication with the multiple monitoring devices 30_1, 30_2, and 30_3. Furthermore, a communication connection is formed between the multiple monitoring devices 30_1, 30_2, and 30_3, in which one of the multiple monitoring devices 30_1, 30_2, and 30_3 (in the example of Fig. 8(b), the monitoring device 30_1) serves as a communication master, and the other monitoring devices (in the example of Fig. 8(b), the monitoring devices 30_2 and 30_3) serve as communication slaves.

[0099] Note that the multiple monitoring devices 30_1, 30_2, and 30_3 may communicate with each other via communication connections established therebetween at the same time, as shown in FIG. 8(b). Alternatively, the multiple monitoring devices 30_1, 30_2, and 30_3 may communicate with each other via communication connections established therebetween at different times. For example, communication between the monitoring devices 30_1 and 30_2 may be performed first, and then, after a predetermined period of time, communication between the monitoring devices 30_1 and 30_3 may be performed. In other words, communication among the multiple monitoring devices 30_1, 30_2, and 30_3 may be performed at different timings in a time-division manner.

[0100] The multiple monitoring devices 30_1, 30_2, and 30_3 periodically communicate with each other via the established communication connections, and at least one of the multiple monitoring devices 30_1, 30_2, and 30_3, for example, the monitoring device 30_1 serving as a communication master, collects battery monitoring information from at least one of the other monitoring devices 30_2 and 30_3. When the battery pack 20 is switched from a non-operating state to an operating state, the at least one monitoring device 30_1 that has collected the battery monitoring information from at least one of the other monitoring devices 30_2 and 30_3 provides the battery monitoring information collected from the other monitoring devices 30_2 and 30_3 and its own battery monitoring information together to the control device 40. Thus, the control device 40 can acquire battery monitoring information regarding the multiple battery stacks 21 simply by communicating with the monitoring device 30_1 that holds the battery monitoring information collected from the other monitoring devices 30_2 and 30_3. Based on the battery monitoring information, the control device 40 can quickly determine whether or not to switch the battery pack 20 to an operating state. As a result, the battery management system 60 according to this embodiment can shorten the time required to transition the battery pack 20 from a non-operating state to an operating state.

[0101] 8(a) and 8(b), the number of monitoring devices 30 is three, but the number is not limited to this and may be two or four or more. Also, the number of control devices 40 is one, but two or more control devices 40 may be provided. When the number of monitoring devices 30 is relatively large, the monitoring devices may be divided into multiple groups, and a communication network as shown in FIG. 8(b) may be formed in each group.

[0102] Next, with reference to the flowchart in FIG. 9, the processing in the control device 40 and the monitoring devices 30_1, 30_2, 30_3 when the battery pack 20 switches from an operating state to a non-operating state and when the battery pack 20 switches from a non-operating state to an operating state will be described.

[0103] In step S40, the control device 40 detects that the ignition switch has been turned off as a trigger indicating that the battery pack 20 is switched from an operating state to a non-operating state. However, the switching of the battery pack 20 from an operating state to a non-operating state may also be detected as a trigger that the vehicle has stopped, that the driver has gotten out of the vehicle, that the doors of the vehicle have been locked, or the like. When the control device 40 detects that the ignition switch has been turned off, it notifies each of the monitoring devices 30_1, 30_2, and 30_3 that the ignition switch has been turned off. This allows each of the monitoring devices 30_1, 30_2, and 30_3 to recognize that the mode of the communication network needs to be changed to a network for the non-operating state of the battery pack 20.

[0104] After notifying each of the monitoring devices 30_1, 30_2, and 30_3 that the ignition switch has been turned off, the control device 40 disconnects communication with the plurality of monitoring devices 30_1, 30_2, and 30_3 in step S41. The processing of step S41 is executed at the latest by the time a communication connection is established between each of the monitoring devices 30_1, 30_2, and 30_3 and periodic communication is started. Therefore, thereafter, the control device 40 does not need to communicate with the plurality of monitoring devices 30_1, 30_2, and 30_3, and power consumption by the control device 40 can be reduced. After disconnecting communication, the control device 40 may transition to a sleep state. This can further reduce power consumption by the control device 40. The control device 40 that has transitioned to the sleep state is triggered and woken up by turning on the ignition switch, which will be described later.

[0105] The plurality of monitoring devices 30_1, 30_2, 30_3 execute a connection accepting operation (scanning operation) and a connection requesting operation (advertising operation) in order to form a communication connection between the plurality of monitoring devices 30_1, 30_2, 30_3, in which one monitoring device 30_1, 30_2, 30_3 serves as a communication parent device (in the example of FIG. 9, the monitoring device 30_1 serves as the communication parent device) and the other monitoring devices 30_1, 30_2, 30_3 serve as communication child devices (in the example of FIG. 9, the monitoring devices 30_2, 30_3 serve as communication child devices). For example, in the example shown in the flowchart of FIG. 9, the monitoring device 30_1 performs the connection accepting operation in step S42, the monitoring device 30_2 performs the connection requesting operation in step S43, and the monitoring device 30_3 performs the connection requesting operation in step S44. Although the monitoring devices 30_1, 30_2, and 30_3 that will be the communication masters may be set in advance, it is preferable to select the monitoring devices 30_1, 30_2, and 30_3 that are expected to take the longest time for the equalization process described later as the communication masters. The equalization process will be described in detail later.

[0106] Then, in step S45, a connection establishment operation between the monitoring device 30_1 and the monitoring devices 30_2 and 30_3 is executed. That is, as the connection establishment operation, the monitoring device 30_1 which is the communication master detects advertisement packets from the monitoring devices 30_2 and 30_3 which are communication slaves, and transmits a connection request (CONNECT_REQ) to the monitoring devices 30_2 and 30_3 which are communication slaves. Furthermore, the monitoring device 30_1 which is the communication master and the monitoring devices 30_2 and 30_3 which are communication slaves exchange unique information.

[0107] 8(b), one monitoring device 30_1 among the plurality of monitoring devices 30_1, 30_2, 30_3 serves as a communication master device, and the other monitoring devices 30_2, 30_3 serve as communication slave devices for the communication master device, i.e., a star-shaped network is formed among the plurality of monitoring devices 30_1, 30_2, 30_3. In this way, when the battery pack 20 is in a non-operating state, the control device 40 does not communicate with the plurality of monitoring devices 30_1, 30_2, 30_3 and does not serve as a communication master device for the plurality of monitoring devices 30_1, 30_2, 30_3, and therefore the power consumption of the control device 40 can be effectively reduced.

[0108] In step S46 of the flowchart in FIG. 9, periodic communication is performed in the star network formed by the plurality of monitoring devices 30_1, 30_2, and 30_3.

[0109] As described above, each of the multiple monitoring devices 30_1, 30_2, 30_3 can acquire battery monitoring information including voltage values ​​of the multiple battery cells 22 included in the battery stack 21. When there is variation in the voltage values ​​of the multiple battery cells 22 that constitute the battery pack 20, the chargeable amount of the battery pack 20 is limited by the battery cell 22 with the maximum voltage value. As a result, the chargeable amount and dischargeable amount of the battery pack 20 are also limited. Therefore, the battery management system 60 according to this embodiment performs an equalization process to equalize the voltage values ​​of the multiple battery cells 22 when the battery pack is in an operating state or a non-operating state.

[0110] The equalization process may be a passive equalization process in which the battery cells 22 having a relatively high voltage value are discharged first so that the voltage values ​​of the plurality of battery cells 22 are equalized to the lowest voltage value, or an active equalization process in which the battery cells 22 having a relatively low voltage value are charged with charges discharged from the battery cells 22 having a relatively high voltage value. Furthermore, the equalization process may be a combination of a passive equalization process and an active equalization process. The function of performing such a passive equalization process and / or an active equalization process may be performed by, for example, the monitoring IC 33 of the monitoring device 30.

[0111] Whether or not an equalization process needs to be performed when the battery pack 20 is in a non-operating state may be determined, for example, by the control device 40 upon detecting that the ignition switch has been turned off, based on battery monitoring information received from each of the monitoring devices 30_1, 30_2, and 30_3. If an equalization process needs to be performed, the control device 40 may instruct each of the monitoring devices 30_1, 30_2, and 30_3 to perform the equalization process. The instruction to perform the equalization process may include, for example, a target voltage value, the content of the equalization process (e.g., whether the equalization process is passive or active), and the like. Alternatively, the monitoring device 30_1, which serves as a communication master through periodic communication in the star-shaped network formed by the above-mentioned plurality of monitoring devices 30_1, 30_2, and 30_3, may determine whether or not an equalization process needs to be performed based on the battery monitoring information acquired by each of the monitoring devices 30_1, 30_2, and 30_3, and instruct each of the monitoring devices 30_1, 30_2, and 30_3 to perform the equalization process. Alternatively, before communication is disconnected, the control device 40 may instruct the execution of equalization processing, and after communication is disconnected, the monitoring device 30_1, which has become the communication parent device, may manage whether or not the equalization processing instructed by the control device 40 has been successfully completed in each of the monitoring devices 30_1, 30_2, and 30_3.

[0112] Furthermore, when the control device 40 determines, based on the battery monitoring information received from each of the monitoring devices 30_1, 30_2, and 30_3, that it is necessary to perform the equalization process while the battery pack 20 is in a non-operating state, it may select the monitoring device 30_1, 30_2, and 30_3 that is expected to take the longest time to complete the equalization process, and instruct the selected monitoring device 30_1, 30_2, and 30_3 to become a communication master device while the battery pack 20 is in a non-operating state. As a result, even if, for example, each of the monitoring devices 30_1, 30_2, and 30_3 is configured to terminate communication after completing the equalization process, the monitoring device 30_1, 30_2, and 30_3 that serves as the communication master device continues communication for the longest time, and therefore can collect information on the completion of the equalization process and battery monitoring information after the equalization process from each of the monitoring devices 30_1, 30_2, and 30_3.

[0113] The monitoring devices 30_1, 30_2, and 30_3 that are expected to take the longest time to complete the equalization process may be, for example, a monitoring device that monitors the battery cell 22 that exhibits the highest voltage value among the multiple battery cells 22, or a monitoring device that monitors the battery stack 21 that includes the highest average voltage values ​​of the multiple battery cells 22 among the multiple battery stacks 21. Alternatively, the monitoring devices 30_1, 30_2, and 30_3 that are expected to take the longest time to complete the equalization process may be monitoring devices that monitor the battery stack 21 that includes the largest voltage difference between the minimum and maximum voltage values ​​of the multiple battery cells 22 among the multiple battery stacks 21.

[0114] When the equalization process is performed, the monitoring devices 30_1, 30_2, and 30_3, which are communication master devices, collect and store the battery monitoring information acquired by each of the monitoring devices 30_1, 30_2, and 30_3 after the equalization process is completed. Also, when the equalization process is not performed, it is preferable that the monitoring devices 30_1, 30_2, and 30_3, which are communication master devices, collect and store the battery monitoring information acquired by each of the monitoring devices 30_1, 30_2, and 30_3 through the periodic communication described above.

[0115] The control device 40 knows which of the monitoring devices 30_1, 30_2, and 30_3 is the communication master device. Therefore, when the control device 40 detects that the ignition switch is turned on, the control device 40 preferentially starts communication with the monitoring devices 30_1, 30_2, and 30_3 that store the battery monitoring information of the other monitoring devices 30_1, 30_2, and 30_3, thereby collectively acquiring the battery monitoring information about the plurality of battery stacks 21. Therefore, based on the battery monitoring information, it can quickly determine whether or not to switch the battery pack 20 to an operating state.

[0116] As described above, periodic communication between the multiple monitoring devices 30_1, 30_2, and 30_3 is performed to instruct execution of the equalization process and to transmit battery monitoring information. Therefore, for example, after the equalization process is completed and / or the transmission of the battery monitoring information is completed, the need for periodic communication decreases. Therefore, the monitoring devices 30_1, 30_2, and 30_3 that have completed the equalization process and / or the transmission of the battery monitoring information may reduce the frequency of periodic communication compared to the previous periodic communication. For example, to reduce the frequency of periodic communication, the cycle of periodic communication may be lengthened, or the transmission of battery monitoring information may be stopped to reduce the amount of communication data per communication and shorten the communication time per communication. In this case, periodic communication may be performed to the extent that communication connection between the monitoring devices 30_1, 30_2, and 30_3 can be maintained.

[0117] Alternatively, the monitoring devices 30_1, 30_2, 30_3 that have completed the equalization process and / or finished transmitting the battery monitoring information may terminate communication with the other monitoring devices 30_1, 30_2, 30_3. However, in this case, when the control device 40 starts a scanning operation in response to the ignition switch being turned on, each of the monitoring devices 30_1, 30_2, 30_3 needs to periodically perform a connection request operation to the control device 40 so that the control device 40 can receive advertisement packets from each of the monitoring devices 30_1, 30_2, 30_3.

[0118] 9, the control device 40 wakes up when the ignition switch is turned on, and detects that the ignition switch has been turned on as a trigger indicating that the battery pack 20 is switched from a non-operating state to an operating state. Alternatively, the trigger that wakes up the control device 40 and indicates that the battery pack 20 is switched from a non-operating state to an operating state may be detected when a user holding a smart key approaches the vehicle, when the vehicle doors are unlocked, when the driver sits in the driver's seat, or the like.

[0119] When the control device 40 detects that the ignition switch has been turned on, it starts a connection accepting operation (scanning operation) in step S48. As shown in step S49 of the flowchart in FIG. 9, the monitoring device 30_1 periodically performs a connection request operation as a communication slave to the control device 40 while performing periodic communication with the other monitoring devices 30_2 and 30_3 as a communication master. The control device 40 performs a connection establishment operation with the monitoring device 30_1 in step S50. That is, the control device 40 receives an advertisement packet from the monitoring device 30_1, transmits a connection request to the monitoring device 30_1, and exchanges unique information with the monitoring device 30_1. Then, the control device 40 notifies the monitoring device 30_1 that the ignition switch has been turned on via the established communication connection. Note that at least one of the monitoring devices 30_2 and 30_1 as communication slaves other than the monitoring device 30_1 as the communication master may periodically perform a connection request operation to the control device 40.

[0120] The monitoring device 30_1, which is notified by the control device 40 that the ignition switch has been turned on, notifies the other monitoring devices 30_2 and 30_3 that the ignition switch has been turned on via the star network shown in Fig. 8(b). This allows each of the monitoring devices 30_2 and 30_3 to understand that the form of the communication network needs to be changed to the star network for the operating state of the battery pack 20 shown in Fig. 8(a).

[0121] The control device 40 and each of the monitoring devices 30_2, 30_3 execute a connection accepting operation (scanning operation) and a connection requesting operation (advertising operation) because the control device 40 serves as a communication parent device for each of the monitoring devices 30_2, 30_3 and each of the monitoring devices 30_2, 30_3 serves as a communication child device for the control device 40. More specifically, the control device 40 continues the connection accepting operation of step S48, and the monitoring devices 30_2, 30_3 execute connection requesting operations in steps S51 and S52. Then, in step S53, a connection establishing operation is executed between the control device 40 and each of the monitoring devices 30_2, 30_3.

[0122] When the battery pack 20 is in a non-operating state, the communication connections between the monitoring devices 30_1, 30_2, and 30_3 forming the star-shaped network shown in Figure 8(b) are disconnected at the latest by the time regular communication between the control device 40 and each of the monitoring devices 30_1, 30_2, and 30_3 begins after the ignition switch is detected as being turned on and notified to each of the monitoring devices 30_1, 30_2, and 30_3.

[0123] (Second embodiment) Next, a battery management system 60 according to a second embodiment will be described with reference to the drawings. The battery management system 60 according to this embodiment has the same configuration as the battery management system 60 according to the first embodiment. Therefore, a description of the configuration of the battery management system 60 according to this embodiment will be omitted.

[0124] The battery management system 60 according to this embodiment, like the first embodiment, switches to a communication mode different from that used when the battery pack 20 is in an inactive state, thereby reducing power consumption by the control device 40. However, unlike the first embodiment, the battery management system 60 according to this embodiment differs from the first embodiment in that the control device 40 does not cut off all communication connections with the multiple monitoring devices 30_1, 30_2, and 30_3, but maintains communication connections with at least one of the multiple monitoring devices 30_1, 30_2, and 30_3. However, communication between the control device 40 and at least one of the multiple monitoring devices 30_1, 30_2, and 30_3 is performed less frequently than communication between the multiple monitoring devices 30_1, 30_2, and 30_3. For example, the communication frequency can be reduced by lengthening the communication cycle or by reducing the amount of communication data by not transmitting battery monitoring information between the control device 40 and one of the multiple monitoring devices 30_1, 30_2, and 30_3. This allows the control device 40 to reduce power consumption while maintaining communication connection with at least one of the plurality of monitoring devices 30_1, 30_2, 30_3.

[0125] FIG. 10 shows the configuration of the communication network in the non-operating state of the battery pack 20 in this embodiment. That is, as shown in FIG. 10, a plurality of monitoring devices 30_1, 30_2, and 30_3 form a star-shaped network with the monitoring device 30_1 as a communication master, and the control device 40 maintains a communication connection with the monitoring device 30_1. Note that the at least one monitoring device with which the control device 40 maintains communication is not limited to the monitoring device 30_1, but may be either one of the other monitoring devices 30_2 or 30_3. Furthermore, when the monitoring devices 30 are divided into a plurality of groups and a communication network as shown in FIG. 8(b) is formed in each group, the control device 40 maintains a communication connection with at least one monitoring device 30 belonging to each group.

[0126] Next, with reference to the flowchart of FIG. 11, the processing of the control device 40 and each of the monitoring devices 30_1, 30_2, 30_3 in this embodiment will be described.

[0127] The processing of step S60 in the flowchart of Fig. 11 is the same as the processing of step S40 in the flowchart of Fig. 9. Then, in step S61, the control device 40 cuts off the communication connections with the monitoring devices 30_2 and 30_3 but maintains the communication connection with the monitoring device 30_1. As described above, the communication between the control device 40 and the monitoring device 30_1 is performed less frequently than the communication between the plurality of monitoring devices 30_1, 30_2 and 30_3. Note that instead of simply maintaining the communication between the control device 40 and the monitoring device 30_1, the roles of the communication master and the communication slave may be reversed, so that the monitoring device 30_1 becomes the communication master and the control device 40 becomes the communication slave.

[0128] The processing of steps S62 to S66 in the flowchart of Fig. 11 is the same as the processing of steps S42 to S46 in the flowchart of Fig. 9. Then, in step S67, when the control device 40 detects that the ignition switch has been turned on, it notifies the monitoring device 30_1 that the ignition switch has been turned on via the maintained communication connection. In response to this notification, the monitoring device 30_1 notifies the other monitoring devices 30_2 and 30_3 that the ignition switch has been turned on via the star network between the monitoring devices 30_1, 30_2, and 30_3 shown in Fig. 10. This allows each of the monitoring devices 30_2 and 30_3 to recognize that it is necessary to change the configuration of the communication network to the star network for the operating state of the battery pack 20 shown in Fig. 8(a).

[0129] Then, the control device 40 becomes a communication parent device of the monitoring devices 30_2 and 30_3, and therefore executes a connection accepting operation in step S68, and each of the monitoring devices 30_2 and 30_3 becomes a communication child device of the control device 40, and therefore executes a connection request operation in steps S69 and S70. Then, in step S71, a connection establishment operation is executed between the control device 40 and each of the monitoring devices 30_1, 30_2 and 30_3.

[0130] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0131] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0132] When an element or layer is referred to as being "on," "coupled," "connected," or "coupled," it may be directly on, coupled, connected, or coupled to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, there are no intervening elements or layers present. Other language used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0133] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms are intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0134] The devices, systems, and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the devices and methods described herein may be implemented by special-purpose hardware logic circuitry. Alternatively, the devices and methods described herein may be implemented by one or more special-purpose computers comprising a processor executing a computer program in combination with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0135] For example, although an example has been shown in which the monitoring device 30 includes the microcomputer 34, the present invention is not limited to this. The monitoring device 30 may employ a battery management system 60 configured without the microcomputer 34. In this configuration, the wireless IC 35 transmits and receives data to and from the monitoring IC 33. The scheduling control of sensing and self-diagnosis by the monitoring IC 33 may be performed by the wireless IC 35 or by the main microcomputer 45 of the control device 40.

[0136] Although an example in which a monitoring device 30 is provided for each battery stack 21 has been shown, this is not limiting. For example, one monitoring device 30 may be provided for multiple battery stacks 21. Multiple monitoring devices 30 may be provided for one battery stack 21.

[0137] Although the example in which the battery pack 11 includes one control device 40 has been described, this is not limiting. The battery pack 11 may include multiple control devices 40. Although the example in which the monitoring device 30 includes one monitoring IC 33 has been described, this is not limiting. The battery pack 11 may include multiple monitoring ICs 33. In this case, a wireless IC 35 may be provided for each monitoring IC 33, or one wireless IC 35 may be provided for the multiple monitoring ICs 33.

[0138] The arrangement and number of the battery stacks 21 and battery cells 22 that make up the battery pack 20 are not limited to the above example. In the battery pack 11, the arrangement of the monitoring device 30 and / or the control device 40 is not limited to the above example.

[0139] In each of the above-described embodiments, the monitoring system of the present disclosure is embodied as a battery management system 60 configured to monitor each battery stack 21 of the battery pack 20. However, the monitoring system of the present disclosure can also be applied to monitor monitored objects other than each battery stack 21 of the battery pack 20. For example, the monitoring system of the present disclosure may be embodied as a system that wirelessly communicates with air pressure sensor units built into each wheel of a vehicle and monitors each air pressure sensor unit. In this case, each monitoring device is provided on each wheel, and at least one control device is provided inside the vehicle. [Explanation of symbols]

[0140] 10...vehicle, 11...battery pack, 12...PCU, 13...MG, 14...ECU, 15...battery, 20...battery pack, 21...battery stack, 22...battery cell, 23...busbar unit, 24...busbar, 25...positive terminal, 26...negative terminal, 27...busbar cover, 30...monitoring device, 31, 311, 312, 313...power supply circuit, 32...multiplexer, 33...monitoring IC, 34...microcontroller, 35...wireless IC, 36...front-end circuit, 37...antenna, 40...control device, 41, 411, 412...power supply circuit, 42...antenna, 43...front-end circuit, 44...wireless IC, 45...main microcontroller, 46...sub-microcontroller, 50...casing, 60...battery management system, 70...sensor

Claims

1. A plurality of monitoring devices (30) provided in the monitored devices and monitoring the monitored devices; a control device (40) that wirelessly communicates with the plurality of monitoring devices and acquires monitoring information of the monitored devices from the plurality of monitoring devices; the monitored device is switched between an active state and an inactive state; When the monitored device is in an inoperable state, a communication connection is formed between the plurality of monitoring devices, in which at least one of the plurality of monitoring devices serves as a communication master and the other monitoring devices serve as communication slaves to the communication master, and the plurality of monitoring devices periodically communicate with each other via the formed communication connection; A monitoring system in which the control device does not serve as a communication master for the plurality of monitoring devices when the monitored devices are in an inoperative state.

2. The monitoring system of claim 1, wherein when the monitored device is in an inoperative state, the control device disconnects communication with the plurality of monitoring devices or communicates with at least one of the plurality of monitoring devices less frequently than communication between the plurality of monitoring devices.

3. 3. The monitoring system according to claim 1, wherein the control device operates by receiving power from a power source separate from a power source that supplies power to the plurality of monitoring devices.

4. When the monitored devices are in an operating state, the control device, as a communication master, performs wireless communication with each of the plurality of monitoring devices, which are communication slaves, via communication connections established individually; The monitoring system according to claim 1 , wherein the plurality of monitoring devices that are communication slaves when the monitored device is in operation include a monitoring device that was a communication master when the monitored device was in a non-operational state.

5. A monitoring system as described in any one of claims 1 to 4, wherein at least one of the multiple monitoring devices, which is a communication parent device when the monitored device is in a non-operating state, collects monitoring information of at least one other monitoring device via communication when the monitored device is in a non-operating state, and provides the collected monitoring information of the other monitoring device together with its own monitoring information to the control device when the monitored device is switched from a non-operating state to an operating state.

6. the monitored device is a battery pack consisting of a plurality of battery stacks, the battery stack includes a plurality of battery cells; each of the plurality of monitoring devices monitors the battery stack as a monitoring target and monitors at least voltage values ​​of the plurality of battery cells included in the battery stack; 6. The monitoring system according to claim 1, wherein, when each of the plurality of monitoring devices performs an equalization process to equalize the voltage values ​​of the plurality of battery cells in an out-of-operation state in which the assembled battery does not need to provide power because the voltage values ​​of the plurality of battery cells are uneven, each of the plurality of monitoring devices terminates communication with the other monitoring devices when the battery cell equalization process is completed, or communicates with the other monitoring devices at a frequency lower than that of communication before the battery cell equalization process is completed.

7. 7. The monitoring system according to claim 6, wherein the monitoring device that is expected to take the longest time to perform the equalization process on the battery cells is selected as the monitoring device that will be the communication master when the battery pack is in an inoperative state.

8. 8. The monitoring system according to claim 7, wherein a monitoring device that monitors a battery cell that exhibits the highest voltage value among the plurality of battery cells, or a monitoring device that monitors a battery stack among the plurality of battery stacks that includes the highest average voltage values ​​of the plurality of battery cells, is regarded as the monitoring device that is expected to require the longest time for the equalization processing of the battery cells.

9. A monitoring system as described in any one of claims 1 to 8, wherein when the control device disconnects the communication connection with the multiple monitoring devices while the monitored device is in a non-operating state, at least one of the multiple monitoring devices periodically sends a connection request signal to the control device, and when the control device detects an instruction to switch the monitored device from a non-operating state to an operating state, it responds to the connection request signal, thereby starting communication with at least one of the multiple monitoring devices and notifying them of the switch instruction.

10. The monitoring system described in claim 9, wherein when the monitored equipment is in a non-operating state, a monitoring device that receives notification of the switching instruction from the control device notifies other monitoring devices of the switching instruction via a communication connection between the multiple monitoring devices.

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