Battery Management System

Abstract

To provide a battery management system capable of highly reliable wireless communication. [Solution] A battery management system for a vehicle includes one or more monitoring devices arranged in a housing that houses a battery, and a control device arranged in the housing that acquires battery information from the monitoring devices and executes predetermined processing. The control device pre-stores, as learning data, data correlating with the electric field strength within the housing for frequency channels that can be used for transmitting and receiving data to and from each of the monitoring devices that wirelessly communicate with the battery management system. The control device determines the frequency channels to be used for frequency channel hopping based on the learning data.

Description

Technical Field

[0001] The disclosure in this specification relates to a battery management system.

Background Art

[0002] Patent Document 1 discloses a battery management system. The description of the prior art document is incorporated herein by reference as an explanation of the technical elements in this specification.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The battery management system described in Patent Document 1 evaluates the communication quality based on the data transmission and reception results between the master device and the slave device, and determines that the communication quality of the currently used frequency channel has deteriorated when the number of reception failures exceeds a threshold value. Then, the frequency hopping pattern is changed to a frequency channel with good communication quality. In this way, since the frequency channel is changed only based on the actual communication quality, a large number of unreliable wireless communications will occur. From the above viewpoints, or from other viewpoints not mentioned, further improvement of the battery management system is required.

[0005] One object to be disclosed is to provide a battery management system capable of reliable wireless communication.

Means for Solving the Problems

[0006] The battery management system disclosed herein is One or more monitoring devices (30) are arranged in a housing (50) that houses the batteries (20, 21, 22) of the vehicle (10) and monitors battery information indicating the state of the batteries. A control device (40) is arranged in the housing, acquires battery information from the monitoring device, and executes predetermined processing. The control device and the monitoring device perform wireless communication using frequency channel hopping, with one being the master device and the other being the slave device. The master device Frequency channels available for data transmission and reception with a slave device performing wireless communication each of them and the relationship at the positions of the control device and the monitoring device with respect to the housing Electric field strength indicating the relationship with Learning data in the non-volatile memory Is stored in advance. Based on the learning data, determine the frequency channels to be used for frequency channel hopping. Execute frequency channel hopping and determine a predetermined frequency channel to be used. Based on the data transmission and reception results with the slave device in the predetermined frequency channel, evaluate the communication quality and accumulate it as communication performance.

[0007] According to the disclosed battery management system, the master device has pre-stored learning data. The learning data is data correlated with the electric field strength in the housing regarding the frequency channels available for data transmission and reception with the slave device. The master device determines the frequency channels to be used for frequency channel hopping based on the pre-stored electric field strength in the housing. As a result, a battery management system capable of highly reliable wireless communication can be provided.

[0008] The disclosed aspects in this specification adopt different technical means to achieve their respective purposes. The reference numerals in parentheses described in the claims and this section exemplify the correspondence with the parts of the embodiments described later and are not intended to limit the technical scope. The purposes, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the attached drawings.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each embodiment, the same reference numerals may be assigned to corresponding components, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other previously described embodiments can be applied to other parts of the configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly shown.

[0011] (First Embodiment) First, based on FIG. 1, the vehicle in which the battery management system according to this embodiment is mounted, particularly, the configuration around the battery pack including the battery management system will be described. FIG. 1 is a diagram showing a schematic configuration of the vehicle. The vehicle is an electric vehicle such as an electric vehicle or a hybrid vehicle.

[0012] <Vehicle> As shown in FIG. 1, the 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. ECU is an abbreviation for Electronic Control Unit.

[0013] The battery pack 11 includes a battery module 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. The battery pack 11 supplies power to the MG13 through the PCU 12. The battery pack 11 is charged through the PCU 12. The battery pack 11 may be referred to as the main battery.

[0014] As shown in FIG. 1, for example, the battery pack 11 is disposed in the front compartment of the vehicle 10. The battery pack 11 may be disposed in the rear compartment, under the seat, or under the floor. For example, in the case of a hybrid vehicle, the compartment where the engine is disposed may be referred to as the engine compartment or the engine room.

[0015] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the MG13 according to the control signal from the ECU 14. The PCU 12 may be referred to as a power converter. The PCU 12 includes, for example, an inverter. The inverter converts a DC voltage into an AC voltage, for example, a three-phase AC voltage, and outputs it to the MG13. The inverter converts the generated power of the MG13 into a DC voltage and outputs it to the converter. The PCU 12 may include a converter. The converter is disposed in the energization path between the battery pack 11 and the inverter. The converter has a function of boosting and bucking the DC voltage.

[0016] The MG13 is an AC rotating electric machine, for example, a three-phase AC synchronous motor in which permanent magnets are embedded in the rotor. The MG13 functions as a driving source for the vehicle 10, that is, an electric motor. The MG13 is driven by the PCU 12 to generate a rotational driving force. The driving force generated by the MG13 is transmitted to the driving wheels. The MG13 functions as a generator during braking of the vehicle 10 and performs regenerative power generation. The generated power of the MG13 is supplied to the battery pack 11 through the PCU 12 and stored in the battery module 20 in the battery pack 11.

[0017] ECU14 is configured to include a computer having a processor, a memory, an input / output interface, a bus for connecting these components, etc. The processor is hardware for 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-transitory physical storage medium that non-temporarily stores or stores programs and data that can be read by a computer. The memory stores various programs executed by the processor.

[0018] ECU14, for example, acquires information about the assembled battery 20 from the battery pack 11, and controls the driving of MG13 and the charging and discharging of the battery pack 11 by controlling the PCU12. ECU14 may acquire information such as the voltage, temperature, current, SOC, and SOH of the assembled battery 20 from the battery pack 11. ECU14 may acquire battery information such as the voltage, temperature, and current of the assembled battery 20 and calculate the SOC and SOH. SOC is an abbreviation for State Of Charge. SOH is an abbreviation for State Of Health.

[0019] The processor of ECU14 executes, for example, a plurality of instructions included in the PCU control program stored in the memory. Thereby, ECU14 constructs a plurality of functional units for controlling the PCU12. In ECU14, a program stored in the memory causes the processor to execute a plurality of instructions, thereby constructing a plurality of functional units. ECU14 may be referred to as an EVECU.

[0020] <Battery Pack> Next, based on FIGS. 2 and 3, an example of the configuration of the battery pack 11 will be described. FIG. 2 is a perspective view schematically showing the inside of the battery pack 11. In FIG. 2, the housing is shown by a two-dot chain line. FIG. 3 is a plan view showing the upper surface of each battery stack.

[0021] As shown in FIG. 2, the battery pack 11 includes a battery module 20, a plurality of monitoring devices 30, a control device 40, and a housing 50. The housing 50 houses other elements constituting the battery pack 11, that is, the battery module 20, the monitoring devices 30, and the control device 40. The housing 50 is made of, for example, metal. The housing 50 may be made of resin or may include a metal part and a resin part.

[0022] Hereinafter, as shown in FIG. 2, among the respective surfaces of the housing 50 which is substantially a rectangular parallelepiped, in the mounting surface on the vehicle 10, the longitudinal direction is indicated as the X direction, and the short side direction is indicated as the Y direction. In FIG. 2, the lower surface is the mounting surface. And the vertical direction perpendicular to the mounting surface is indicated as the Z direction. The X direction, the Y direction, and the Z direction are in a positional relationship of being orthogonal to each other. In the present 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 vertical direction corresponds to the Z direction. The arrangements in FIGS. 2 and 3 are merely examples, and the battery pack 11 may be arranged in any manner with respect to the vehicle 10.

[0023] The battery module 20 has a plurality of battery stacks 21 arranged side by side in the X direction. The battery stacks 21 may be referred to as battery blocks or battery modules. The battery module 20 is configured by connecting a plurality of battery stacks 21 in series. Each battery stack 21 has a plurality of battery cells 22. The battery stack 21 has a plurality of battery cells 22 connected in series. The battery stack 21 of the present embodiment is configured by connecting a plurality of battery cells 22 arranged side by side in the Y direction in series. The battery module 20 provides the above - described DC voltage source. The battery module 20, the battery stack 21, and the battery cell 22 correspond to the battery.

[0024] The battery cell 22 is a secondary battery that generates an electromotive force by a chemical reaction. As the secondary battery, for example, a lithium - ion secondary battery or a nickel - metal hydride secondary battery can be adopted. The lithium - ion secondary battery is a secondary battery using lithium as a charge carrier. In addition to a general lithium - ion secondary battery having a liquid electrolyte, it may also include a so - called all - solid - state battery using a solid electrolyte.

[0025] On the upper surface of each battery stack 21, linear bus bar units 23 are arranged at both ends in the X direction. That is, a pair of bus bar units 23 are arranged in each battery stack 21. The bus bar unit 23 electrically connects a plurality of battery cells 22. As shown in FIG. 3, each battery cell 22 is formed in a flat shape and is stacked such that the sides overlap each other in the Y direction. The battery cell 22 has a positive electrode terminal 25 and a negative electrode terminal 26 that protrude in the Z direction, more specifically, in the Z+ direction indicating upward, at both ends in the X direction. The battery cells 22 are stacked such that the positive electrode terminals 25 and the negative electrode terminals 26 are alternately arranged in the Y direction.

[0026] Each bus bar unit 23 has a plurality of bus bars 24 that electrically connect the positive electrode terminal 25 and the negative electrode terminal 26, and a bus bar cover 27 that covers the plurality of bus bars 24. The bus bar 24 is a plate material made of a metal with good conductivity such as copper. The bus bar 24 electrically connects the positive electrode terminal 25 and the negative electrode terminal 26 of adjacent battery cells 22 in the Y direction. Thereby, in each battery stack 21, a plurality of battery cells 22 are electrically connected in series. In each battery stack 21, the positive electrode terminal 25 of the battery cell 22 arranged on one end side in the Y direction is connected to a predetermined positive electrode wiring, and the negative electrode terminal 26 of the battery cell 22 arranged on the other end side is connected to a predetermined negative electrode wiring.

[0027] The bus bar cover 27 is formed using an electrical insulating material such as resin. The bus bar cover 27 is provided linearly from one end to the other end of the battery stack 21 along the Y direction so as to cover the plurality of bus bars 24.

[0028] The monitoring device 30 is provided individually for a plurality of battery stacks 21. As shown in FIG. 2, the monitoring device 30 is disposed between a pair of bus bar units 23 in each battery stack 21. The monitoring device 30 is fixed to the bus bar unit 23 with screws or the like. The monitoring device 30 is configured to be capable of wireless communication with a control device 40 as will be described later. An antenna 37 (to be described later) provided in the monitoring device 30 is disposed so as not to overlap with the bus bar unit 23 in the Z direction, that is, so as to protrude from the bus bar unit 23 in the Z direction.

[0029] The control device 40 is attached to the outer side surface of the battery stack 21 disposed at one end in the X direction. The control device 40 is configured to be capable of wireless communication with each monitoring device 30. An antenna 42 (to be described later) provided in the control device 40 is disposed at approximately the same height as the antenna 37 of the monitoring device 30 in the Z direction. That is, the antenna 42 of the control device 40 is provided so as to protrude from the bus bar unit 23 in the Z direction.

[0030] In the battery pack 11, the monitoring device 30 and the control device 40 provide a battery management system 60 as will be described later. That is, the battery pack 11 includes the battery management system 60.

[0031] <Battery Management System> Next, based on FIG. 4, the schematic configuration of the battery management system will be described. FIG. 4 is a block diagram showing the configuration of the battery management system.

[0032] As shown in FIG. 4, the battery management system 60 includes a plurality of management devices (SBM) 30 and a control device (ECU) 40. The control device 40 may be referred to as a battery ECU or BMU. BMU is an abbreviation for Battery Management Unit. The battery management system 60 is a system that manages the battery using wireless communication. In the battery management system 60 of the present embodiment, wireless communication is executed between one control device 40 and a plurality of monitoring devices 30. In this wireless communication, a frequency band used for short-range communication, for example, the 2.4 GHz band or the 5 GHz band, is used.

[0033] <Monitoring device> First, the monitoring device 30 will be described. The configurations of the respective monitoring devices 30 are common to each other. 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). Communication between the respective elements within the monitoring device 30 is performed by wire.

[0034] The power supply circuit 31 generates the operating power for the other circuit elements included in the monitoring device 30 using the voltage supplied from the battery stack 21. In the present 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.

[0035] The multiplexer 32 is a selection circuit that inputs the detection signals of a plurality of sensors 70 provided in the battery pack 11 and outputs them as one signal. The multiplexer 32 selects (switches) the input according to the selection signal from the monitoring IC 33 and outputs it as one signal. The sensors 70 include sensors that detect the physical quantities of the respective battery cells 22, and sensors for discriminating which battery cell 22 it is. The physical quantity detection sensors include, for example, voltage sensors, temperature sensors, current sensors, and the like.

[0036] The monitoring IC 33 senses (acquires) battery information such as cell voltage, cell temperature, and cell discrimination through the multiplexer 32 and transmits it to the microcomputer 34. The monitoring IC 33 may be referred to as a cell monitoring circuit (CSC). CSC is an abbreviation for Cell Supervising Circuit. The monitoring IC 33 may have a function of performing a failure diagnosis of the circuit part of the monitoring device 30 including itself and transmitting the diagnosis result together with the battery information as monitoring data. When the monitoring IC 33 receives data requesting the acquisition of battery information transmitted from the microcomputer 34, it senses the battery information through the multiplexer 32 and transmits the monitoring data including at least the battery information to the microcomputer 34. The monitoring IC 33 corresponds to the monitoring unit.

[0037] The microcomputer 34 is a microcomputer including a CPU which is a processor, a ROM and a RAM which are memories, an input / output interface, and a bus connecting these. The CPU constructs a plurality of functional units by executing various programs stored in the ROM while using the temporary storage function of the RAM. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory.

[0038] The microcontroller 34 controls the sensing and self-diagnosis schedules by the monitoring IC 33. The microcontroller 34 receives the monitoring data transmitted from the monitoring IC 33 and transmits it to the wireless IC 35. The microcontroller 34 transmits data requesting the acquisition of battery information to the monitoring IC 33. As an example, when the microcontroller 34 of the present embodiment receives data requesting the acquisition of battery information transmitted from the wireless IC 35, it transmits data requesting the acquisition of battery information to the monitoring IC 33.

[0039] The wireless IC 35 includes an RF circuit (not shown) and a microcontroller for wirelessly transmitting and receiving data. The wireless IC 35 has a transmission function of modulating transmission data and oscillating at the frequency of the RF signal. The wireless IC 35 has a reception function of demodulating reception data. RF is an abbreviation for radio frequency.

[0040] The wireless IC 35 modulates the data including the battery information transmitted from the microcontroller 34 and transmits it to 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 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 the communication between the SBM 30 and the control device 40.

[0041] The wireless IC 35 receives the data transmitted from the control device 40 via the antenna 37 and the front-end circuit 36 and demodulates it. When the wireless IC 35 receives data including, for example, a request for acquisition and transmission of battery information, as a response to the request, it acquires monitoring data including battery information through the monitoring IC 33 and transmits it to the control device 40.

[0042] The front-end circuit 36 has a matching circuit for impedance matching between the wireless IC 35 and the antenna 37, and a filter circuit for removing unnecessary frequency components.

[0043] Antenna 37 converts an RF signal, which is an electrical signal, into a radio wave and radiates it into space. Antenna 37 receives a radio wave propagating in space and converts it into an electrical signal.

[0044] <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 by wire.

[0045] The power supply circuit 41 generates an operating power supply for other circuit elements included in the control device 40 using the voltage supplied from the battery (BAT) 15. The battery 15 is a DC voltage source separate from the battery pack 11 mounted on the vehicle 10. The battery 15 may be referred to as an auxiliary battery because it supplies power to the accessories of the vehicle 10. In the present 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. For simplicity of the drawing, 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.

[0046] Antenna 42 converts an RF signal, which is an electrical signal, into a radio wave and radiates it into space. Antenna 42 receives a radio wave propagating in space and converts it into an electrical signal.

[0047] The front-end circuit 43 has a matching circuit for impedance matching between the wireless IC 44 and the antenna 42, and a filter circuit for removing unnecessary frequency components.

[0048] The wireless IC 44 has an RF circuit (RF) 440 and a microcomputer (MC) 441 to wirelessly transmit and receive data. Similar to the wireless IC 35, the wireless IC 44 has a transmitter function and a receiver function. The wireless IC 44 receives the data transmitted from the monitoring device 30 via the antenna 42 and the front-end circuit 43 and demodulates it. Then, it transmits the monitoring data including the battery information to the main microcomputer 45. The wireless IC 44 receives the data transmitted from the main microcomputer 45, modulates it, and transmits it 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 transmission data and then 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, etc. of the communication between the monitoring device 30 and the control device 40.

[0049] The wireless IC 44 has a learning data storage unit (DS) 442. The learning data storage unit 442 is constructed, for example, in the non-volatile memory of the microcomputer 441. The learning data storage unit 442 may be constructed in a non-volatile storage medium provided in the control device 40 separately from the memory included in the microcomputer 441. The learning data storage unit 442 stores learning data. The learning data is data correlated with the electric field strength in the housing 50 regarding the frequency channels that can be used for data transmission and reception with the monitoring device 30. The learning data storage unit 442 stores learning data for each of the monitoring devices 30 that wirelessly communicates with the ECU 40. The wireless IC 44 determines the frequency channels to be used for frequency channel hopping based on the learning data. The learning data and the determination of the frequency channels using the learning data will be described later.

[0050] The main microcomputer 45 is a microcomputer including a CPU, a ROM, a RAM, an input / output interface, a bus connecting these components, and the like. The ROM stores various programs executed by the CPU. The main microcomputer 45 generates a command for requesting the processing of monitoring data including battery information from the monitoring device 30, and transmits transmission data including the command to the wireless IC 44. The main microcomputer 45 of the present embodiment generates a command for requesting the acquisition and transmission of monitoring data including battery information. The requests described in this specification may be referred to as instructions.

[0051] The main microcomputer 45 receives monitoring data including battery information transmitted from the wireless IC 44, and executes predetermined processing based on the monitoring data. For example, the main microcomputer 45 executes a process of transmitting the acquired battery information to the ECU 14. The main microcomputer 45 may calculate the SOC and / or SOH based on the battery information, and transmit the battery information including the calculated SOC and SOH to the ECU 14. The main microcomputer 45 may execute an equalization process of equalizing the voltages of the respective battery cells 22 based on the battery information. The main microcomputer 45 may acquire the IG signal of the vehicle 10 and execute the above-described processing according to the driving state of the vehicle 10. The main microcomputer 45 may execute a process of detecting an abnormality of the battery cell 22 based on the battery information, or may transmit abnormality detection information to the ECU 14.

[0052] The sub-microcomputer 46 is a microcomputer including a CPU, a ROM, a RAM, an input / output interface, a bus connecting these components, and the like. The ROM stores various programs executed by the CPU. The sub-microcomputer 46 executes 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 state of the main microcomputer 45. The sub-microcomputer 46 may monitor the state of the wireless IC 44.

[0053] <Wireless communication> Next, based on FIG. 5, the wireless communication between the monitoring device 30 and the control device 40 will be described. FIG. 5 is a diagram showing an example of a communication sequence between the monitoring device 30 and the control device 40. In FIG. 5, the wireless communication between one monitoring device 30 and the control device 40 will be described. In FIG. 5, the monitoring IC 33 is shown as MIC 33, the wireless IC 35 is shown as WIC 35, and the control device 40 is shown as ECU 40.

[0054] As shown in FIG. 5, first, the wireless IC 35 of the monitoring device 30 and the control device 40 execute startup processing such as connection establishment (step S10). Startup refers to, for example, when the operating power is supplied. In a configuration where power is constantly supplied from the battery stack 21 or the battery 15, startup occurs during the vehicle 10 manufacturing process or after component replacement at a repair factory. At startup, it may also be when a startup signal such as an IG signal is supplied. For example, when the IG signal is switched from off to on by the user's operation, startup occurs.

[0055] At startup, the startup processing is executed respectively between the control device 40 and all the monitoring devices 30 that are the connection targets of the wireless communication with the control device 40. The startup processing includes, for example, a connection establishment process for establishing a wireless communication connection and a pairing process for exchanging unique information for encrypted communication. The startup processing includes a process of sharing initial information regarding frequency channel hopping. The initial information includes, for example, a hopping pattern or a function for hopping.

[0056] When the processing of step S10 is completed, the monitoring device 30 and the control device 40 execute data communication periodically. As shown in FIG. 5, the control device 40 transmits transmission data including a request for acquiring monitoring data including battery information and a transmission request, that is, request data, to the monitoring device 30 (step S20).

[0057] When the wireless IC 35 of the monitoring device 30 receives the request data, it transmits a request for acquiring monitoring data including battery information to the monitoring IC 33 (step S21). In the present embodiment, the wireless IC 35 transmits the acquisition request to the monitoring IC 33 via the microcomputer 34.

[0058] When the monitoring IC 33 receives an acquisition request, it performs sensing (step S22). The monitoring IC 33 performs sensing and acquires battery information of each battery cell 22 through the multiplexer 32. Further, the monitoring IC 33 performs failure diagnosis of the circuit.

[0059] Next, the monitoring IC 33 transmits monitoring data including battery information to the wireless IC 35 (step S23). In the present embodiment, monitoring data including the failure diagnosis result is transmitted together with the battery information. The monitoring IC 33 transmits it to the wireless IC 35 via the microcomputer 34.

[0060] When the wireless IC 35 receives the monitoring data acquired by the monitoring IC 33, it transmits transmission data including the monitoring data, that is, response data, to the control device 40 (step S24).

[0061] When the control device 40 receives the response data, it executes a predetermined process (step S25) based on the monitoring data. In the present embodiment, the control device 40 that executes the request process corresponds to the master device, and the monitoring device 30 that executes the response process corresponds to the slave device.

[0062] The processes of steps S20 to S25 described above are executed between the control device 40 and each monitoring device 30. The battery management system 60 periodically executes the processes of steps S20 to S25.

[0063] The control device 40 determines the frequency channel to be used by performing frequency channel hopping for each data transmission / reception cycle, and transmits request data and receives response data on the determined frequency channel (frequency). The control device 40 performs frequency channel hopping according to the initial information until the unusable channel described later is determined. When the unusable channel is determined, the control device 40 performs frequency channel hopping in consideration of the unusable channel.

[0064] Similarly, the monitoring device 30 also determines the frequency channel to be used by performing frequency channel hopping for each transmission / reception cycle, and receives the requested data and transmits the response data on the determined frequency channel (frequency). The monitoring device 30 performs frequency channel hopping according to the information shared with the control device 40. Therefore, the monitoring device 30 and the control device 40 can transmit and receive data using the same frequency channel. The control device 40 and the monitoring device 30 switch the frequency channel to be used for each transmission / reception cycle by frequency channel hopping.

[0065] <Learning data> Next, the learning data will be described with reference to FIG. 6. FIG. 6 is a diagram showing the electric field strength distribution inside the housing 50 of the battery pack 11. FIG. 6 shows the electromagnetic field simulation results at a predetermined timing at a predetermined frequency. In FIG. 6, as an example, the control device 40 (wave source) is provided at approximately the center of the metal housing 50.

[0066] When the control device 40 radiates radio waves of a predetermined frequency, due to the interference between the transmitted wave and the reflected wave, as shown in FIG. 6, high and low electric field strength portions are generated inside the housing 50. This is more prominent when the housing 50 is made of metal, but the same is true even when it is made of resin. The reflected wave is generated by the reflection of the transmitted wave by the metal elements constituting the battery pack 11, for example, the reflection by the housing 50, the reflection by the harness (not shown), etc. Also, in the case of resin, it is generated by the reflection of the transmitted wave by the metal bodies existing around the battery pack 11 in the vehicle 10, for example, the reflection by the metal vehicle frame.

[0067] Also, in a closed space such as the housing 50, even if the phase changes, there are generally high electric field strength portions and low electric field strength portions. Particularly, when the housing 50 is made of metal, it becomes clear due to the shielding function of the housing 50. The positions of each monitoring device 30 and the control device 40 are determined inside the housing 50, and thus in the vehicle 10. That is, they are fixed positions. In the same type of vehicle 10, the positions of the monitoring device 30 and the control device 40 are common (identical) to each other.

[0068] In this embodiment, the control device 40 has data correlated with the electric field strength in the housing 50 acquired in advance as learning data. The learning data is written into the learning data storage unit 442 of the wireless IC 44, for example, before the vehicle 10 is shipped, specifically, during the manufacture of the battery pack 11. The learning data may be obtained, for example, by measurement in the vehicle 10 at the prototype stage or by electromagnetic field simulation. As described above, since the electric field strength changes depending on the phase, it is preferable to use data correlated with the average value of the electric field strength at a predetermined time or data correlated with the maximum value of the electric field strength at a predetermined time.

[0069] The learning data includes at least data correlated with the electric field strength at the position of the control device 40 and data correlated with the electric field strength at the position of each monitoring device 30. The positions of the monitoring device 30 and the control device 40 are preferably the positions of the antennas 37 and 42, but may be positions slightly deviated from the antennas 37 and 42. The learning data may be data obtained by finely meshing the housing 50 and correlating the electric field strength at each coordinate. In this case, the positions of the monitoring device 30 and the control device 40 may be associated with the coordinates. The data correlated with the electric field strength may be the electric field strength itself, that is, the above-described average value of the electric field strength or the maximum value of the electric field strength. Also, a correlation value that is not the electric field strength itself may be used. For example, data obtained by classifying the electric field strength into levels may be used.

[0070] The learning data includes, for example, data correlated with the electric field strength for each frequency channel used for data communication between the control device 40 and the monitoring device 30. The learning data may include data for a part of the available frequency channels. The learning data includes data correlated with the electric field strength for all the monitoring devices 30 that perform wireless communication with the control device 40. The learning data shows the relationship between the frequency channel (frequency) and the electric field strength in the control device 40 and the monitoring device 30. Hereinafter, the high and low of the electric field strength in the control device 40 and the monitoring device 30 may be simply referred to as the high and low of the electric field strength.

[0071] <Determination Process of Target Channel for Use> Next, based on FIGS. 7 to 11, the determination process of the target channel for use using learning data will be described. This process is executed by the wireless IC 44 of the control device 40 which is the master device. The control device 40 determines the frequency channel to be used for frequency channel hopping. Hereinafter, the frequency channel may be indicated as ch.

[0072] FIG. 7 shows an example of available frequency channels. The available channels are the frequency channels allocated for data communication among a plurality of frequency channels. As shown in FIG. 7, between one monitoring device 30 and the control device 40, the frequency channels available for data transmission and reception (data communication) are predetermined.

[0073] As an example, in this embodiment, a total of 10 channels from ch1 to ch10 are available. The frequency channels have a predetermined frequency width and different frequencies from each other. As shown in FIG. 7, the frequency of ch1 is the lowest and the frequency of ch10 is the highest. The number of available frequency channels for data transmission and reception may be more or less than 10 channels. The monitoring device 30 and the control device 40 may share the information of available frequency channels as initial information, for example, or may have the information of available frequency channels common to each other in advance.

[0074] FIG. 8 shows an example of the target channel determination process executed by the wireless IC 44 of the control device 40. First, in order to execute data communication with one monitoring device 30, the wireless IC 44 of the control device 40 executes frequency channel hopping and determines the frequency channel to be used in the current transmission and reception cycle (step S100). As described above, the control device 40 performs frequency channel hopping for each data transmission and reception cycle.

[0075] The method of frequency channel hopping is not particularly limited. As an example, the control device 40 of the present embodiment determines the frequency channel to be used according to a frequency channel hopping pattern. Hereinafter, the frequency channel hopping pattern may be referred to as a hopping pattern. Alternatively, a predetermined function may be used to determine the frequency channel to be used. The hopping pattern and the function are included in the initial information described above, for example.

[0076] FIG. 9 shows an example of a hopping pattern. The hopping pattern shown in FIG. 9 is a pattern shared as initial information. That is, it is a hopping pattern before considering unavailable channels. In the present embodiment, the frequency channels to be used are switched in the order of ch1 → ch4 → ch7 → ch10 → ch3 → ch6 → ch9 → ch2 → ch5 → ch8 → ch1. In this way, the process of shifting the frequency channels by a predetermined number can also be performed by a function. For example, at the time of the first data communication after the execution of the startup process, ch1 is used. Here, as an example, it is assumed that ch4 is determined as the frequency channel to be used.

[0077] After the execution of step S100, the control device 40 executes transmission and reception processing using the determined frequency channel (step S110). The frequency channel hopping and the transmission and reception processing correspond to the transmission of the requested data and the reception of the response data shown in FIG. 5. The monitoring device 30 also determines the frequency channel to be used according to the same hopping pattern as the control device 40 before the execution of the transmission and reception processing. For example, in the transmission and reception cycle in which the control device 40 determines ch4, the monitoring device also determines ch4.

[0078] After the execution of step S110, the control device 40 evaluates the communication quality (step S120) and accumulates it as communication performance (step S130). The control device 40 evaluates the quality of the communication performed this time based on the transmission and reception result of step S110. The control device 40 evaluates whether the communication quality is normal or deteriorated. The control device 40 individually accumulates the communication evaluation results as communication performance for each frequency channel.

[0079] The control device 40 evaluates the communication quality based on information regarding the reception state of, for example, response data (response signal). The control device 40 may evaluate that the communication quality has deteriorated when, for example, it is unable to receive the response data. The control device 40 may evaluate that the communication quality has deteriorated when it has received the data but has detected a communication error through an inspection performed during reception, for example, an inspection using an error detection code. The control device 40 may evaluate that the communication quality has deteriorated when, for example, retransmission processing is necessary. That is, when communication fails, it may be evaluated that the communication quality has deteriorated. The control device 40 may evaluate that the communication quality has deteriorated when, for example, the received signal strength (RSSI) is lower than a predetermined value. RSSI is an abbreviation for Received Signal Strength Indicator. The control device 40 evaluates that the communication quality is normal when the evaluation criteria are met.

[0080] The control device 40 may obtain information regarding the reception state of the request data (request signal) from the monitoring device 30 as part of the communication data and evaluate the communication quality. The control device 40, which is the master device, evaluates the communication quality based on the information regarding the reception state of the request data and / or the information regarding the reception state of the response data, and accumulates it as communication performance.

[0081] Figure 10 shows the communication performance of each frequency channel. In Figure 10, for clarity, the performance of communication quality deterioration among the communication performance is hatched. In this way, for each process of step S130, the control device 40 accumulates, as communication performance, the evaluation performance of normal communication quality or the evaluation performance of deteriorated communication quality. As a result, the communication performance increases by one for the used frequency channel.

[0082] After the execution of step S130, the control device 40 determines whether the communication performance of the frequency channel used this time exceeds the reference number of times ST (step S140). As described above, the phase of the signal changes. Therefore, it is preferable to perform the unusable determination in step S160 in a state where the communication performance for 360° of the phase is accumulated, preferably accumulated a plurality of times. Considering this point, in the present embodiment, the reference number of times ST is set within a range of 1000 to several tens of thousands of times. The reference number of times ST in the present embodiment is a predetermined value (fixed value). The reference number of times ST is stored in advance in the memory of the microcomputer 441, for example.

[0083] If it is determined in step S140 that the communication performance is equal to or less than the reference number of times ST, the control device 40 ends a series of processes. The control device 40 maintains the frequency channel currently set as the use target of frequency channel hopping.

[0084] If it is determined in step S140 that the communication performance exceeds the reference number of times ST, the control device 40 sets a threshold value TH based on the learning data (step S150). The control device 40 sets the threshold value TH for the frequency channel used in the transmission / reception process of step S110. As shown by the broken line in FIG. 10, the threshold value TH is set individually for each frequency channel based on the learning data. In the present embodiment, the electric field strength in the control device 40 and one monitoring device 30 when using ch4 is lower than that when using the other ch1 to 3, 5 to 10. For this reason, the control device 40 sets the threshold value TH of ch4 to a value lower than the threshold values TH of the other ch1 to 3, 5 to 10. That is, the threshold value of ch4 is set so that ch4 is easily determined to be unusable.

[0085] After the execution of step S150, the control device 40 executes an unusable determination for the frequency channel used this time (step S160). The control device 40 determines whether it will be unusable from the next time onward by comparing a value correlated with communication quality degradation in the communication performance of the used frequency channel with the threshold value TH. The value correlated with communication quality in the communication performance is, for example, the ratio of the communication quality degradation performance during the communication performance. Instead of the ratio, the number of times of the communication quality degradation performance may be used.

[0086] In step S160, when the correlation value of communication quality degradation is equal to or less than the threshold TH, the control device 40 determines that there is no problem with the use of the frequency channel used this time in subsequent uses, and ends a series of processes. That is, the control device 40 currently maintains the frequency channel set as the use target of frequency channel hopping.

[0087] In step S160, when the correlation value of communication quality degradation exceeds the threshold TH, the control device 40 determines that the use of the frequency channel used this time is not possible in subsequent uses, and sets a non-usable channel. For example, in FIG. 10, the ratio of communication quality degradation of ch4 exceeds the threshold TH. In this case, the control device 40 determines that ch4 is unusable and sets it as a non-usable channel.

[0088] When it is determined that the channel is not usable, the control device 40 determines the frequency channel to be used (step S170) and ends a series of processes. The control device 40 determines the frequency channel to be used by excluding the non-usable channel from the use targets of frequency channel hopping.

[0089] FIG. 11 shows an example of a hopping pattern considering non-usable channels. The control device 40 excludes, for example, ch4, which is a non-usable channel, from the hopping pattern. When frequency channel hopping is performed in the next cycle after the transmission / reception cycle using ch1, the frequency channel to be used is switched to ch7. Instead of excluding it from the hopping pattern, frequency channel hopping may be performed again when a non-usable channel is selected so as not to use the non-usable channel.

[0090] After the above-described startup processing is completed, the control device 40 repeatedly executes the processes of steps S100 to S170. The control device 40 executes the above-described determination process for the use target channel in the transmission and reception of data with each monitoring device 30.

[0091] <Shared Process> Next, based on FIGS. 12 and 13, information sharing with the monitoring device 30, which is a slave device, will be described. FIG. 12 is a flowchart showing an example of the sharing process executed by the control device 40. FIG. 13 is a timing chart showing an example of data communication including channel information.

[0092] The control device 40 executes the process shown in FIG. 12 using the process of step S170 described above as a trigger. As shown in FIG. 12, the wireless IC 44 of the control device 40 transmits data including channel information to the monitoring device 30 (step S200). The channel information is, for example, information on frequency channels determined to be unavailable channels. The channel information may be, for example, information on frequency channels to be used after excluding unavailable channels.

[0093] After executing step S200, the control device 40 determines whether or not a response signal to the transmission signal of step S200 has been received within a predetermined time after executing the transmission process of step S200 (step S210). If a response signal is received, the series of processes ends. If a response signal is not received, the process of step S200 is executed again.

[0094] FIG. 13 shows an example in which the control device 40 performs data transmission and reception with three monitoring devices 30, specifically SBM1, SBM2, and SBM3. FIG. 13 shows an example in which one of the frequency channels is determined to be unavailable between the control device 40 and SBM2. Tx indicates data transmission, and Rx indicates data reception. SBM1(D), SBM2(D), and SBM3(D) indicate the transmission and reception of monitoring data requests and responses. SBM2(CI) indicates the transmission and reception of data including channel information (CI).

[0095] After executing data transmission and reception with SBM2, the control device 40 continues to perform data transmission and reception including channel information with SBM2. Before executing communication with SBM3, the control device 40 shares channel information with SBM2. The transmission and reception of channel information may be executed until the frequency channel determined to be unusable is reused in SBM2. For example, in the hopping pattern shown in FIG. 9, the transmission of the information of ch4 which is unusable may be performed after data transmission and reception using ch9. In this case, channel information can be shared between SBM2 using ch9. The channel information is information regarding frequency channel hopping that is shared subsequently and is different from the initial information.

[0096] <Summary of the First Embodiment> As described above, the positions of the monitoring device 30 and the control device 40 are determined within the housing 50 and thus in the vehicle 10. When an electric wave of a predetermined frequency (predetermined channel) is radiated from the control device 40 which is the master device, high and low electric field intensity portions are generated in the housing 50 due to the interference between the transmitted wave and the reflected wave. In a closed space such as the housing 50, there are generally a portion with a high electric field intensity and a portion with a low electric field intensity even if the phase changes. When the electric field intensity in the monitoring device 30 and the control device 40 is low, deterioration of communication quality such as communication failure or a decrease in the received signal is more likely to occur than when the electric field intensity is high. That is, in the positional relationship between the monitoring device 30 and the control device 40, there are a frequency channel (frequency) where communication quality is likely to deteriorate and a frequency channel where communication quality is less likely to deteriorate.

[0097] The control device 40 of this embodiment has, in advance, data correlated with the electric field strength inside the housing 50 as learning data. The learning data is data correlated with the electric field strength inside the housing 50 for frequency channels that can be used for data transmission and reception with the monitoring device 30, which is a slave device. Based on the data correlated with the electric field strength, the control device 40 excludes frequency channels where communication quality is likely to deteriorate from the targets for frequency channel hopping. That is, it determines frequency channels where communication quality is less likely to deteriorate as the targets for frequency channel hopping. As a result, a battery management system 60 capable of highly reliable wireless communication can be provided. Thereby, it is possible to suppress the occurrence of communication failures. That is, it is possible to suppress the omission of monitoring data such as battery information.

[0098] In the case of wireless communication, the communication speed is often slower and the communication frequency is often lower compared to wired communication. Therefore, when an abnormality occurs in at least one of physical quantities such as voltage, or when an abnormality is detected based on fault diagnosis information, if there is an omission of monitoring data, the value may change rapidly. When the value changes rapidly, the control will change rapidly. Although there is no problem with safety, there is a possibility of affecting the operability. On the other hand, according to this embodiment, it is possible to suppress the omission of monitoring data indicating an abnormality. Thereby, it is possible to suppress the influence on the operability.

[0099] Also, by suppressing the omission of monitoring data, it becomes possible to accurately estimate elements estimated by the accumulation of monitoring data, such as the accumulation of battery damage. Also, in some cases, the detection of an abnormality is performed based on the number of times a threshold value is exceeded. Also in this case, by suppressing the omission of monitoring data, it becomes possible to advance the detection timing of the abnormality.

[0100] The electric field strength is also affected by factors other than the initially determined factors (initial factors) such as the above-described arrangement and frequency channel (frequency). The electric field strength within the housing 50 can change due to variable factors such as the temperature, humidity, foreign matter, and vibration of the usage environment. For example, when the temperature rises, the electric field strength decreases compared to when the temperature is low. When the humidity increases, the electric field strength decreases due to the influence of moisture in the air. The electric field strength also decreases due to foreign matter such as dust. Further, when the position of a metal body such as a harness is displaced due to vibration, the electric field strength changes. When the propagation path of radio waves is displaced due to vibration, the electric field strength changes.

[0101] The control device 40 of the present embodiment evaluates the communication quality based on the transmission and reception results of data in a predetermined frequency channel and accumulates it as communication performance. Then, when a value correlated with communication quality degradation in the communication performance exceeds a threshold TH, it is determined that the predetermined frequency channel is unusable and excluded from the usage targets. In this way, using a value based on the actual transmission and reception results, specifically, a value correlated with communication quality degradation in the communication performance, it is determined whether it is unusable. Thereby, the influence of variable factors such as temperature and vibration can be considered (reflected).

[0102] Further, the control device 40 sets the threshold TH for each frequency channel based on the learning data. That is, based on the electric field strength, the threshold TH is set individually for each frequency channel. For example, the threshold TH for a frequency channel with a low electric field strength is made stricter than the threshold TH for a frequency channel with a high electric field strength. In the present embodiment, in order to consider the influence of the initial factors and the influence of the variable factors, the reliability of wireless communication can be further enhanced.

[0103] When the thresholds TH are common to each other in the usable frequency channels, a large number of communication failures and the like occur wastefully until the uniform threshold TH is reached. According to the present embodiment, since the threshold TH is set for each frequency channel in consideration of the influence of the initial factors, the threshold TH is reached earlier for the frequency channels with a low electric field strength. Thereby, communication failures can be reduced, and as a result, the omission of battery information can be suppressed.

[0104] <Modification Example> Although an example in which the reference number of times ST used in the process of step S140 is a fixed value has been shown, the present invention is not limited thereto. The reference number of times ST may also be set for each frequency channel based on the learning data. That is, the reference number of times ST of the frequency channel with low field strength in the monitoring device 30 and the control device 40 may be made smaller than the reference number of times ST of the frequency channel with high field strength.

[0105] Although not specifically mentioned, the transmission and reception results of the sharing process shown in FIG. 12 may also be evaluated for communication quality and accumulated as communication performance.

[0106] An example in which the frequency channel determined to be unusable is excluded and the next frequency channel in the hopping pattern is used has been shown, but the present invention is not limited thereto. After excluding the frequency channel determined to be unusable and using a predetermined frequency channel that does not follow the rules, the process may return to the hopping pattern. The frequency channel after the determination of unusability may be determined by adding a predetermined number to the unusable channel. For example, when ch4 is determined to be unusable, ch10 obtained by adding 6, which is a predetermined number, may be used, and after ch10, the process may return to the hopping pattern and ch7 may be used. If the predetermined number is made larger than the normal hopping interval, the next frequency channel to be used can be separated from the unusable channel. The same applies when using a function.

[0107] Also, the frequency channel to be used after the determination of unusability may be determined in advance. For example, after the determination of unusability, ch2 may always be used, and then the frequency channel to be used may be determined according to the hopping pattern or function.

[0108] The timing at which the control device 40 sets the threshold value TH is not limited to step S150. The control device 40 may set the threshold value TH before executing the unusable determination process (step S160). For example, the control device 40 may individually set the threshold value TH for all frequency channels after executing the startup process and before executing data communication. According to this, every time the communication record exceeds the reference number ST, it is not necessary to set the threshold value TH.

[0109] Although an example has been shown in which the control device 40 transmits channel information (CI) to SBM2 when determining that one of the frequency channels is unusable in the usage target channel determination process with one monitoring device 30 (SBM2), the present invention is not limited to this. Channel information may be transmitted not only to SBM2 but also to other monitoring devices (SBM1, SBM3). For example, channel information may be transmitted to SBM1 following SBM1 (D) shown in FIG. 13, and channel information may be transmitted to SBM3 following SBM3 (D). That is, the unusable channel may be shared among all the monitoring devices 30 that wirelessly communicate with the control device 40.

[0110] Frequency channel information may be used as learning data. The frequency channel information is, for example, information on a frequency channel in which the field strength is higher than a predetermined threshold value, and / or information on a frequency channel in which the field strength is lower than a predetermined threshold value. As learning data, data for each (all) of the available frequency channels may be included, or data for some of the frequency channels may be included. For example, when the learning data includes frequency channel information in which the field strength is lower than a predetermined threshold value and frequency channel information in which the field strength is higher than the threshold value, the threshold value TH of the frequency channel with a low field strength may be set to a value lower than the threshold value TH of the frequency channel with a high field strength. For example, when the learning data includes only frequency channel information in which the field strength is lower than a predetermined threshold value, for example, the threshold value TH of the frequency channel included in the learning data may be set to a value lower than the threshold value TH of the frequency channel not included in the learning data.

[0111] (Second Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be incorporated. In the preceding embodiment, the communication performance was accumulated for each frequency channel to determine unavailability. Instead, the communication performance may be accumulated for each group consisting of a plurality of consecutive frequency channels as a single unit to determine unavailability.

[0112] FIG. 14 shows an example of the target channel determination process executed by the control device 40 in the battery management system 60 according to this embodiment. FIG. 15 shows an example of the communication performance of each group and the threshold TH set based on the learning data. In FIG. 15, similar to FIG. 10, the threshold TH is shown by a dashed line. Also, for clarity, the performance of communication quality degradation among the communication performances is hatched.

[0113] The processes of steps S100 to S120 shown in FIG. 14 are the same as those of steps S100 to S120 shown in FIG. 8 of the preceding embodiment. The control device 40 (wireless IC 44) determines the frequency channel to be used by frequency channel hopping and performs data transmission and reception processing with one monitoring device 30. Then, based on the transmission and reception results, the communication quality is evaluated.

[0114] After the execution of step S120, the control device 40 accumulates the result of the communication quality evaluation performed in step S120 as the communication performance of the group (step S130A). The control device 40 of this embodiment does not accumulate the communication performance individually for each frequency channel. The control device 40 sets a group consisting of a plurality of consecutive frequency channels as a single unit and accumulates the communication performance in group units.

[0115] As shown in FIG. 15 for example, the control device 40 divides the available 10 channels into 5 groups of 2 channels each. In FIG. 15, the first group (1G) includes ch1 and ch2. The second group (2G) includes ch3 and ch4. The third group (3G) includes ch5 and ch6. The fourth group (4G) includes ch7 and ch8. The fifth group (5G) includes ch9 and ch10. For example, the control device 40 accumulates the communication quality evaluation result of 1 channel and the communication quality evaluation result of 2 channels as the communication record of the first group (1G).

[0116] After the execution of step S130A, the control device 40 determines whether the communication record of the group including the frequency channel used this time exceeds the reference number ST (step S140A). If it is determined in step S140A that the communication record of the group is equal to or less than the reference number ST, the control device 40 ends the series of processes. The control device 40 determines to maintain the frequency channel currently set as the target of frequency channel hopping.

[0117] If it is determined in step S140A that the communication record of the group exceeds the reference number ST, the control device 40 sets the threshold TH of the group based on the learning data (step S150A). The control device 40 sets the threshold TH for the group including the frequency channel used in the transmission / reception process of step S110. As shown by the dashed line in FIG. 15, the threshold TH is set individually for each group based on the learning data. In this embodiment, since the electric field strengths of ch7 and / or ch8 are low, the threshold TH of the fourth group (4G) including ch7 and ch8 is set to a value lower than the threshold TH of the other groups (1G to 3G, 5G).

[0118] After the execution of step S150A, the control device 40 executes the unusable determination of the group including the frequency channel used this time (step S160A). The control device 40 determines whether it will be unusable from the next time onwards by comparing the value correlated with the communication quality degradation in the communication record of the corresponding group with the threshold TH.

[0119] In step S160A, when the value correlated with communication quality degradation is equal to or less than the threshold TH, the control device 40 determines that there is no problem with the corresponding group for subsequent use, and ends the series of processes. That is, the control device 40 currently determines to maintain the frequency channel set as the target of frequency channel hopping.

[0120] In step S160A, when the value correlated with communication quality degradation exceeds the threshold TH, the control device 40 determines that the corresponding group cannot be used in subsequent times. The control device 40 determines that all frequency channels in the group cannot be used. For example, in FIG. 15, the ratio of communication quality degradation of the fourth group (4G) exceeds the threshold TH, and the control device 40 determines that the fourth group, that is, ch7 and ch8 cannot be used.

[0121] When it is determined that it cannot be used, the control device 40 executes the process of step S170 as in FIG. 8 and ends the series of processes. The control device 40 determines the frequency channels to be used by excluding the frequency channels included in the unusable group from the targets of frequency channel hopping. For example, when using the hopping pattern shown in FIG. 9 and determining that the fourth group cannot be used, a new hopping pattern may be determined by excluding ch7 and ch8. Instead of excluding from the hopping pattern, when an unusable channel (ch7 or ch8) is selected, frequency channel hopping may be performed again so as not to use the unusable channel.

[0122] <Summary of the Second Embodiment> According to this embodiment, the same effects as those of the configuration described in the previous embodiment can be achieved. Specifically, the control device 40 evaluates the communication quality based on the transmission and reception results of data in a predetermined frequency channel, and accumulates the communication performance in units of groups. Then, when a value correlated with communication quality degradation in the communication performance of a group exceeds the threshold TH, it is determined that all frequency channels within the group are unusable and excluded from the usage targets. In this way, using a value based on the actual data transmission and reception results, specifically, a value correlated with communication quality degradation in the communication performance, it is determined whether it is unusable. Thereby, the influence of variable factors such as temperature and vibration can be considered (reflected).

[0123] Also, the control device 40 sets the threshold TH for each group based on the learning data. That is, based on the electric field strength, the threshold TH is set individually for each group. For frequencies that are consecutive to each other, the positional relationship of the strength and weakness of the electric field strength is closer than that of frequencies that are far apart from each other. Therefore, even if the threshold TH is grouped together, the reliability of wireless communication can be improved considering the influence of initial elements.

[0124] In this embodiment, the communication performance and the threshold TH are managed in units of groups, and it is determined whether it is unusable in units of groups. Thereby, the processing load on the control device 40 (master device) can be reduced.

[0125] The configuration described in this embodiment can be combined with the configurations described in the previous embodiment and the modification example, except that the frequency channel unit is replaced with a group unit.

[0126] (Third Embodiment) This embodiment is a modification example based on the preceding embodiment, and the description of the preceding embodiment can be incorporated. For the frequency channel determined to be unusable, it may be excluded from the usage targets of frequency channel hopping after the determination. Alternatively, it may be set to return when a predetermined condition is satisfied.

[0127] FIG. 16 shows an example of the return process executed by the control device 40 in the battery management system 60 according to the present embodiment. When the control device 40 sets an unusable channel, it executes the return process shown below.

[0128] As shown in FIG. 16, first, the control device 40 sets return conditions based on the learning data (step S300). When setting the threshold TH individually for each frequency channel, the control device 40 sets the return conditions individually for each frequency channel. When setting the threshold TH individually for each group, the control device 40 sets the return conditions individually for each group.

[0129] The return conditions may be the number of transmissions and receptions after the unusable determination, for example, the number of receptions of monitoring data. Also, it may be the number of times the activation signal such as the IG signal is turned on and off, or the travel distance. For example, in the case of the number of times the activation signal is turned on and off, the control device 40 sets the number of times required for the return of the frequency channel with low field strength to be more than the number of times required for the return of the frequency channel with high field strength based on the learning data.

[0130] After executing step S300, the control device 40 determines whether or not the return conditions are satisfied (step S310). If it is determined that the return conditions are not satisfied, the process of step S310 is executed again.

[0131] If it is determined in step S310 that the return conditions are satisfied, the control device 40 resets the communication record (step S320) and ends the series of processes. When setting the return conditions individually for each frequency channel, at least the communication record of the frequency channel that has satisfied the return conditions is reset, and the frequency channel that was set as unusable is returned to the usable target. When setting the return conditions individually for each group, at least the communication record of the group that has satisfied the return conditions is reset, and all the frequency channels included in the group are returned to the usable target.

[0132] When one frequency channel or one group satisfies the return condition, the control device 40 may reset only the communication performance of the frequency channel or group that satisfies the return condition. The control device 40 may reset the communication performance for all the frequency channels available for data transmission and reception (for example, for 10 channels). That is, all the communication performances may be reset collectively.

[0133] <Summary of the Third Embodiment> According to this embodiment, learning data is used for the return condition for returning an unusable channel. By using learning data, a difference occurs in the return time. A frequency channel with a low electric field strength, that is, a frequency channel where the communication quality is likely to deteriorate, becomes difficult to return. On the other hand, a frequency channel with a high electric field strength, that is, a frequency channel where the communication quality is unlikely to deteriorate, becomes easy to return. Thereby, compared with a configuration with a uniform return condition, the number of occurrences of communication quality deterioration can be reduced. Therefore, the reliability can be further enhanced.

[0134] The configuration described in this embodiment can be combined with either the configuration described in the first embodiment or the configuration described in the second embodiment.

[0135] (Fourth Embodiment) This embodiment is a modification example based on the preceding embodiments, and the descriptions of the preceding embodiments can be incorporated. In the preceding embodiments, the relationship between the execution timing of the use target channel determination process and the running state of the vehicle 10 was not particularly mentioned. Instead, the use target channel determination process may be carried out in association with the running state of the vehicle 10.

[0136] FIG. 17 shows the processing timing of step S110, that is, the timing of the data transmission and reception process, in the battery management system 60 according to this embodiment. As shown in FIG. 17(a), the control device 40 may execute the use target channel determination process including the data transmission and reception process only during running. That is, during non-running, the use target channel determination process may not be carried out.

[0137] As shown in FIG. 17(b), the control device 40 may execute a use target channel determination process including data transmission and reception processing during traveling and non-traveling. That is, the use target channel determination process may be performed during non-traveling. Non-traveling refers to a period when an activation signal such as an IG signal is off, or a period when the vehicle 10 is in a parked state while the activation signal is on. Even when the activation signal is off, in the case of a configuration in which power is constantly supplied from the battery stack 21 or the battery 15, the control device 40 can execute the use target channel determination process during non-traveling.

[0138] Note that the sharing process shown in FIG. 12 and the return process shown in FIG. 16 can be performed in combination with the use target channel determination process. That is, the use target channel determination process, the sharing process, and the return process may be executed during non-traveling.

[0139] <Summary of the Fourth Embodiment> According to the present embodiment, the use target channel determination process can be executed in association with the traveling state of the vehicle. During non-traveling, the temperature is lower than during traveling. The load on the battery pack 20 is low. There is no vibration due to traveling. Thus, the influence of variable factors is small. Therefore, the level of the electric field strength in the initial elements, that is, the control device 40 and the monitoring device 30, greatly affects the communication quality. By using the learning data of the electric field strength, the determination accuracy of unusable channels can be improved.

[0140] In the present embodiment, an example is shown in which the use target channel determination process is executed only during traveling or during traveling and non-traveling. For example, during traveling, only the processes of step S100 and step S110 may be executed, and during non-traveling, the processes of steps S100 to S170 may be executed. During traveling, only the processes of steps S100 to S130 may be executed, and during non-traveling, the processes of steps S100 to S170 may be executed. Thereby, the processing load and communication load of the control device 40 during traveling can be reduced.

[0141] The configuration described in this embodiment can be combined with any of the configurations described in the first embodiment, the configuration described in the second embodiment, and the configuration described in the third embodiment.

[0142] (Fifth Embodiment) This embodiment is a modification example based on the preceding embodiments, and the descriptions of the preceding embodiments can be incorporated by reference. In the preceding embodiments, a threshold value for determining unusable channels was set based on learning data. Instead of this, the frequency channels to be used for frequency channel hopping may be directly determined based on the learning data.

[0143] FIG. 18 shows an example of a communication sequence between the monitoring device 30 and the control device 40 in the battery management system 60 according to this embodiment. FIG. 18 shows the timing of executing the usable channel determination process. In FIG. 18, similar to FIG. 5, the monitoring IC 33 is shown as MIC 33, the wireless IC 35 is shown as WIC 35, and the control device 40 is shown as ECU 40. FIG. 18 shows the timing of executing the usable channel determination process.

[0144] As shown in FIG. 18, after the control device 40 executes the process of step S10, that is, the startup process, and before executing the data communication process after step S20, the control device 40 executes the usable channel determination process (step S15).

[0145] The control device 40 determines the frequency channels to be used for frequency channel hopping based on the initial information and the above-described learning data. Among the plurality of available frequency channels, the control device 40 does not use the frequency channels with low field strength in the control device 40 and the monitoring device 30, and determines the frequency channels with high field strength as the ones to be used. For example, the frequency channels with field strength higher than a predetermined threshold value are used, and the frequency channels with field strength lower than the threshold value are set as unusable.

[0146] The control device 40 shares the information of the frequency channel determined in step S15 with the monitoring device 30 by transmitting the information of the target channel to be used to the wireless IC 35 of the monitoring device 30. In the startup process, the control device 40 and the monitoring device 30 share the initial information regarding frequency channel hopping. The control device 40 performs frequency channel hopping according to the initial information and transmits the information of the target channel to be used on a predetermined frequency channel. In order to perform frequency channel hopping according to the initial information, the control device 40 and the monitoring device 30 can use a common frequency channel with each other and share the information of the target channel to be used.

[0147] The process of step S15 described above is executed between the control device 40 and each monitoring device 30. After the execution of step S15, the control device 40 executes the transmission process of the request data (step S20). The control device 40 performs frequency channel hopping using the frequency channel determined in step S15 as the target and determines the frequency channel to be used. The control device 40 transmits the request data on the determined frequency channel (frequency). After the execution of step S15, the battery management system 60 periodically executes the processes of steps S20 to S25.

[0148] <Summary of the Fifth Embodiment> According to this embodiment, the control device 40, which is the master device, executes the target channel determination process after the execution of the startup process. The control device 40 determines the frequency channel to be used for frequency channel hopping based on the pre-stored learning data before transmitting and receiving data. The control device 40 does not have to execute the channel determination process during the regular communication of data with the monitoring device 30. Thereby, the communication load can be reduced.

[0149] The control device 40 may evaluate the communication quality along with the transmission and reception of data and accumulate the evaluation results as communication performance. That is, the processes of steps S100 to S130 (S130A) may be periodically executed. By accumulating the communication performance, it becomes possible to utilize it for the update of the learning data described later.

[0150] Although an example in which the use target channel determination process is performed after the execution of the startup process has been shown, the present invention is not limited to this. The control device 40 may execute the use target channel determination process between when it starts up and when data transmission / reception with the monitoring device 30 is performed. For example, the use target channel determination process may be included in the startup process.

[0151] When the learning data is a fixed value, that is, when the update of the learning data described later is not executed, the control device 40 and the monitoring device 30 may each execute the use target channel determination process based on the learning data. The monitoring device 30 is also pre-stored with the same learning data as that of the control device 40. The processing content of the use target channel determination process is common between the control device 40 and the monitoring device 30. Thereby, the frequency channels used for frequency channel hopping can be shared without performing data communication.

[0152] As described in the previous embodiment, as learning data, for example, information on frequency channels where the electric field strength is higher than a predetermined threshold value may be used, or information on frequency channels where the electric field strength is lower than a predetermined threshold value may be used. The learning data may include information on frequency channels to be used as use targets and / or information on frequency channels that cannot be used.

[0153] (Sixth Embodiment) This embodiment is a modification example based on the preceding embodiment, and the description of the preceding embodiment can be incorporated by reference. In the preceding embodiment, the learning data was a fixed value. Instead, the learning data may be a variable value.

[0154] FIG. 19 shows the update process executed by the control device 40 in the battery management system 60 according to this embodiment. The control device 40 executes the update process at a predetermined cycle.

[0155] As shown in FIG. 19, the control device 40 determines whether or not a predetermined event has occurred (step S400). The predetermined event may occur, for example, at the switching timing of an activation signal such as an IG signal. The predetermined event may occur, for example, when the activation signal switches from on to off, or may occur when the activation signal switches from off to on. The predetermined event may occur, for example, every predetermined travel distance. The predetermined event may occur, for example, every time the number of received monitoring data reaches a predetermined number.

[0156] When it is determined in step S400 that a predetermined event has occurred, the control device 40 updates the learning data based on the accumulated communication performance (step S410). The control device 40 may update the learning data by fusing the initial learning data and the communication performance according to a preset rule. For example, the control device 40 determines a frequency channel in which the communication quality is likely to deteriorate and a frequency channel in which the communication quality is unlikely to deteriorate from the ratio of communication quality deterioration in the communication performance, and uses them as new learning data. Then, the control device 40 may update the learning data by replacing the initial learning data with the new learning data.

[0157] <Summary of the Sixth Embodiment> According to the present embodiment, the control device 40, which is the master device, updates the learning data using the accumulated communication performance for each predetermined event. According to this, it is possible to determine unusable channels according to the actual usage environment, and thus to determine the frequency channels to be used. For example, in a case where the influence of variable factors such as temperature and vibration is large, highly reliable wireless communication can be performed.

[0158] The configuration described in the present embodiment can be combined with any of the first to fifth embodiments.

[0159] (Other Embodiments) The disclosure in this specification, drawings, etc. is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of components and / or elements shown in the embodiments. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which the components and / or elements of the embodiments are omitted. The disclosure includes the replacement or combination of components and / or elements between one embodiment and another. The technical scope disclosed is not limited to the description of the embodiments. Some of the technical scopes disclosed are indicated by the description of the claims, and should be construed to include all changes within the meaning and scope equivalent to the description of the claims.

[0160] The disclosure in the specification, drawings, etc. is not limited by the description of the claims. The disclosure in the specification, drawings, etc. includes the technical idea described in the claims, and furthermore extends to more diverse and extensive technical ideas than the technical idea described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being restricted by the description of the claims.

[0161] When an element or layer is referred to as being "on", "connected to", "attached to", or "coupled to" another element or layer, it may be directly on, connected to, attached to, or coupled to the other element or layer, and there may be intervening elements or intervening layers. In contrast, when an element is referred to as being "directly on", "directly connected to", "directly attached to", or "directly coupled to" another element or layer, there are no intervening elements or intervening layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between", "adjacent" versus "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.

[0162] Spatially relative terms such as "inside", "outside", "beneath", "below", "lower", "above", "upper", etc. are used herein to facilitate description of the relationship of one element or feature to another element or feature as illustrated. Spatially relative terms can be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the drawings. For example, if the device in the figures is turned over, an element described as "beneath" or "directly beneath" another element or feature would then be oriented "above" the other element or feature. Thus, the term "beneath" can encompass both an orientation of above and below. The device may be oriented in other directions (rotated 90 degrees or other orientations), and the spatially relative descriptors used in this specification are to be interpreted accordingly.

[0163] Examples where a microcomputer or an IC provides means and / or functions have been shown, but the present invention is not limited thereto. Each means and / or function may be realized by a dedicated computer including a processor that executes a computer program. Alternatively, it may be realized using a dedicated hardware logic circuit. Further, it may be realized by one or more dedicated computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. The computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. The means and / or functions can be provided by software recorded in a physical memory device and a computer that executes the software, software only, hardware only, or a combination thereof. For example, some or all of the functions provided by a processor may be realized as hardware. Examples of realizing a certain function as hardware include realizing it using one or more ICs or the like. The processor may be realized using an MPU, a GPU, or a DFP instead of a CPU. The processor may be realized by combining multiple types of arithmetic processing units such as a CPU, an MPU, and a GPU. The processor may be realized as a system on chip (SoC). Further, various processing units may be realized using an FPGA or an ASIC. The various programs only need to be stored in a non-transitory physical recording medium. As the storage medium for the programs, various storage media such as an HDD, an SSD, a flash memory, and an SD card can be adopted. DFP is an abbreviation for Data Flow Processor. SoC is an abbreviation for System on Chip. FPGA is an abbreviation for Field Programmable Gate Array. ASIC is an abbreviation for Application Specific Integrated Circuit. HDD is an abbreviation for Hard disk Drive. SSD is an abbreviation for Solid State Drive. SD is an abbreviation for Secure Digital.

[0164] For example, although an example in which the monitoring device 30 includes the microcomputer 34 has been shown, the present invention is not limited thereto. As shown in FIG. 20, a battery management system 60 having a configuration in which the monitoring device 30 does not include the microcomputer 34 may be employed. FIG. 20 corresponds to FIG. 4. In this configuration, the wireless IC 35 transmits and receives data to and from the monitoring IC 33. Regarding the scheduling control of sensing and self-diagnosis by the monitoring IC 33, the wireless IC 35 may execute it, or the main microcomputer 45 of the control device 40 may execute it.

[0165] The arrangement and number of the battery stack 21 and the battery cells 22 that constitute the battery pack 20 are not limited to the above-described examples. In the battery pack 11, the arrangement of the monitoring device 30 and / or the control device 40 is not limited to the above-described examples.

[0166] Although an example in which the battery pack 11 includes one control device 40 has been shown, the present invention is not limited thereto. A plurality of control devices 40 may be provided. The battery pack 11 may include one or more monitoring devices 30 and one or more control devices 40. The battery management system 60 may include a plurality of wireless communication systems constructed between the control device 40 and one or more monitoring devices 30.

[0167] Although an example in which the monitoring device 30 includes one monitoring IC 33 has been shown, the present invention is not limited thereto. A plurality of monitoring ICs 33 may be provided. In this case, a wireless IC 35 may be provided for each monitoring IC 33, or one wireless IC 35 may be provided for a plurality of monitoring ICs 33.

[0168] Although an example in which the monitoring device 30 is arranged for each battery stack 21 has been shown, the present invention is not limited thereto. For example, one monitoring device 30 may be arranged for a plurality of battery stacks 21. A plurality of monitoring devices 30 may be arranged for one battery stack 21.

[0169] Although an example in which the wireless IC 44 includes the microcomputer 441 has been shown, the present invention is not limited thereto. A configuration without the microcomputer 441 may also be used. The main microcomputer 45 may provide a part of the functions of the above-described wireless IC 44. For example, the wireless IC 35 may have a configuration without a microcomputer. The microcomputer 34 may provide a part of the functions of the above-described wireless IC 35.

[0170] Although an example in which the wireless IC 44 of the control device 40 executes the above-described use target channel determination process and the like has been shown, the present invention is not limited thereto. Any element of the control device 40 may execute the process. For example, the main microcomputer 45 may execute some processes.

[0171] Although an example in which the control device 40 is the master device and the monitoring device 30 is the slave device has been shown, the present invention is not limited thereto. Each of the above-described embodiments can be applied to a configuration in which one of the control device 40 and the monitoring device 30 is the master device and the other is the slave device, and wireless communication is performed using frequency channel hopping. For example, the monitoring device 30 may be the master device and the control device 40 may be the slave device. In this case, the monitoring device 30 stores the learning data in advance. The master device stores, in advance, as learning data, data correlated with the electric field strength in the housing for each frequency channel that can be used for data transmission and reception between the master device and each of the slave devices that perform wireless communication. The master device determines the frequency channels to be used for frequency channel hopping based on the learning data.

Description of Reference Numerals

[0172] 10…Vehicle, 11…Battery pack, 12…PCU, 13…MG, 14…ECU, 15…Battery, 20…Module battery, 21…Battery stack, 22…Battery cell, 23…Bus bar unit, 24…Bus bar, 25…Positive terminal, 26…Negative terminal, 27…Bus bar cover, 30…Monitoring device, 31, 311, 312, 313…Power supply circuit, 32…Multiplexer, 33…Monitoring IC, 34…Microcomputer, 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, 440…RF circuit, 441…Microcomputer, 442…Learning data storage unit, 45…Main microcomputer, 46…Sub microcomputer, 50…Housing, 60…Battery management system, 70…Sensor

Claims

1. One or more monitoring devices (30) arranged in a housing (50) that houses the batteries (20, 21, 22) of the vehicle (10) and monitors battery information indicating the state of the batteries; A control device (40) that acquires the battery information from the monitoring device and executes predetermined processing. The control device and the monitoring device perform wireless communication using frequency channel hopping, with one as the master device and the other as the slave device. The master device: Pre-stores in a non-volatile memory learning data indicating the relationship between each of the frequency channels available for data transmission and reception with the slave device performing the wireless communication and the electric field strength at the positions of the control device and the monitoring device with respect to the housing. Based on the learning data, determines the frequency channels to be used for the frequency channel hopping. Executes the frequency channel hopping to determine a predetermined frequency channel to be used. A battery management system that evaluates communication quality based on the data transmission and reception results with the slave device in the predetermined frequency channel and accumulates it as communication performance.

2. The master device: When a value correlated with communication quality degradation exceeds a threshold in the communication performance of the predetermined frequency channel, determines the predetermined frequency channel as an unusable channel and excludes it from the usage targets, thereby determining the frequency channels to be used. The battery management system according to claim 1, wherein the threshold is individually set for each of the frequency channels available for data transmission and reception with the slave device based on the learning data.

3. The battery management system according to claim 2, wherein the master device sets the threshold according to the electric field strength of each of the frequency channels available for data transmission and reception with the slave device.

4. The master device: When the unusable channel satisfies the recovery condition, resets the communication performance at least for the unusable channel and returns it to the usage targets. The battery management system according to claim 2 or claim 3, wherein the recovery condition is individually set for each of the available frequency channels based on the learning data.

5. The battery management system according to claim 1, wherein the master device determines a frequency channel to be used based on the learning data after startup and before starting data transmission and reception with the slave device.

6. The master device determines a predetermined frequency channel to be used by executing the frequency channel hopping, evaluates the communication quality based on the data transmission and reception results with the slave device in the predetermined frequency channel and accumulates it as the communication performance, and updates the learning data using the accumulated communication performance for each predetermined event. The battery management system according to claim 1.

7. The battery management system according to any one of claims 1 to 6, wherein the antenna of the control device is disposed within the housing.

8. The master device determines the frequency channel to be used by determining the predetermined frequency channel as an unusable channel and excluding it from the usage target when the communication performance exceeds a predetermined reference number of times and a value correlated with communication quality degradation in the communication performance of the predetermined frequency channel exceeds a threshold value, and sets the threshold value individually for the frequency channels that can be used for data transmission and reception with the slave device based on the learning data. The battery management system according to claim 1.

9. In the arrangement direction of the control device and the monitoring device, a plurality of metal members are disposed between the control device and the monitoring device. The battery management system according to claim 1 or claim 7.

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