Battery monitoring system, wireless communication program, and wireless communication method

Abstract

To provide a battery monitoring system, a wireless communication program, and a wireless communication method that release restrictions on the use of a communication channel based on communication quality.SOLUTION: A battery monitoring system 100 includes a battery control device 40, and a battery monitoring device 30 that acquires battery information of battery cells 22 and transmits the battery information to the battery control device 40 via wireless communication. The battery control device 40 is configured to determine and store communication quality for each communication channel for each battery monitoring device 30 as a communication partner. The battery control device 40 also calculates, at a predetermined timing, the number of battery monitoring devices 30 for which the communication quality is determined to be poor for each communication channel, evaluates each communication channel based on these numbers, and releases the usage restriction on any communication channel from among a plurality of usage-restricted communication channels in accordance with the evaluation, thereby allowing its use.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a battery monitoring system, a wireless communication program, and a wireless communication method. [Background technology]

[0002] In recent years, there have been battery monitoring systems that transmit or receive battery information by wireless communication. In some of these battery monitoring systems, the slave unit transmits information about the reception state together with the battery information to the master unit. The master unit then grasps the communication quality of each communication channel based on the received information about the reception state, and uses this information to select a communication channel for the next and subsequent transmissions. Such a battery monitoring system is described, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6514694 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a battery monitoring system, a communication channel (frequency channel) with poor communication quality is prohibited from use until a predetermined condition is met, specifically, until a certain period of time has elapsed. After the certain period of time has elapsed, information regarding the communication quality of the prohibited communication channel is erased, making the channel usable again.

[0005] However, in a battery monitoring system, the arrangement of the parent device and the child device is generally not changed within a limited space such as the inside of a battery pack. Therefore, unless the external environment changes, the communication quality of the communication channel does not change much over time. Therefore, if communication channels that have been prohibited from use over time were made available for use uniformly, this could lead to the use of communication channels with poor communication quality, which could have a negative impact on wireless communication.

[0006] The present invention has been made in consideration of the above circumstances, and its main object is to provide a battery monitoring system, a wireless communication program, and a wireless communication method that lift restrictions on the use of a communication channel based on communication quality. [Means for solving the problem]

[0007] The battery monitoring system for solving the above problem is a battery monitoring system that monitors a battery unit, and includes a battery control device that transmits control information via wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices that acquire battery information of the battery unit in accordance with the control information and return the battery information via wireless communication. The battery monitoring system also includes a communication quality determination unit that determines and stores the communication quality for each of the battery monitoring devices that have become the communication partner for each of the communication channels, and a restriction lifting unit that calculates, at a predetermined timing, the number of the battery monitoring devices that have been determined to have poor communication quality or the number of the battery monitoring devices that have not been determined to have poor communication quality for each of the communication channels, evaluates each of the communication channels based on these numbers, and lifts the usage restriction on one of the plurality of communication channels that has been restricted in use in accordance with the evaluation, thereby allowing its use.

[0008] The wireless communication program for solving the above problem is a battery monitoring system that monitors a battery unit, and is implemented by the battery monitoring system, which includes a battery control device that transmits control information via wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices that acquire battery information of the battery unit in accordance with the control information and return the battery information via wireless communication. The wireless communication program includes a communication quality determination process that determines and stores the communication quality for each of the battery monitoring devices that have become the communication partner for each of the communication channels, and a restriction release process that calculates, at a predetermined timing, the number of the battery monitoring devices that have been determined to have poor communication quality, or the number of the battery monitoring devices that have not been determined to have poor communication quality, evaluates each of the communication channels based on these numbers, and releases the usage restriction on one of the plurality of communication channels that has been restricted in use in accordance with the evaluation, thereby allowing its use.

[0009] A wireless communication method for solving the above problem is implemented by a battery monitoring system that monitors a battery unit, the battery monitoring system comprising: a battery control device that transmits control information via wireless communication using a communication channel selected from a plurality of available communication channels; and a plurality of battery monitoring devices that acquire battery information of the battery unit in accordance with the control information and return the battery information via wireless communication. The wireless communication method comprises a communication quality determination process that determines and stores the communication quality for each of the battery monitoring devices that have become the communication partner for each of the communication channels, and a restriction release process that calculates, at a predetermined timing, the number of the battery monitoring devices whose communication quality has been determined to be poor, or the number of the battery monitoring devices whose communication quality has not been determined to be poor, evaluates each of the communication channels based on these numbers, and lifts the usage restriction on one of the plurality of communication channels whose usage has been restricted in accordance with the evaluation, thereby allowing its use.

[0010] As a result, it is possible to preferentially release the use of a communication channel with a small number of battery monitoring devices whose communication quality has become poor, or a communication channel with a large number of battery monitoring devices whose communication quality has not been determined to be poor. Therefore, it is possible to prevent the release of the usage restriction on a communication channel whose communication quality is likely to become poor, compared to a case where the restriction is released uniformly based on time, etc. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a vehicle. [Diagram 2] FIG. 2 is a block diagram showing the configuration of a battery pack. [Diagram 3] FIG. 2 is a perspective view showing a schematic configuration of a battery pack. [Figure 4] 4 is a flowchart showing the flow of data communication. [Diagram 5] 4 is a flowchart showing the flow of data communication. [Figure 6] 11 is a flowchart showing the flow of a connection establishment process. [Figure 7] FIG. 2 is a diagram showing frequency bands of communication channels. [Figure 8] FIG. 4 is a diagram showing a data flow when a connection is established. [Figure 9] FIG. 4 is a diagram showing an example of a channel map. [Figure 10] FIG. 11 is a flowchart showing a release process. [Figure 11] FIG. 11 is a flowchart showing a release process according to the second embodiment. [Figure 12] 13 is a flowchart showing the flow of data communication according to the third embodiment. [Figure 13] FIG. 13 is a diagram showing an example of a channel map according to the third embodiment. [Figure 14] FIG. 13 is a flowchart showing a release process according to the third embodiment. [Figure 15] FIG. 13 is a diagram showing an example of a channel map according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the battery monitoring system, the wireless communication program, and the wireless communication method according to the present disclosure will be described in detail with reference to the drawings. Note that, between the embodiments and the modifications, the same or corresponding parts in the drawings are given the same reference numerals, and the description thereof will not be repeated in principle. Below, the case where the present invention is applied to a vehicle will be described, but the present invention can also be applied to applications other than vehicles, such as flying objects such as drones, ships, construction machinery, agricultural machinery, etc.

[0013] (First embodiment) <Vehicle> FIG. 1 is a diagram showing a schematic configuration of a vehicle 10. The vehicle 10 is an electrically powered vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV). The vehicle 10 includes a battery pack 11 (shown as "Battey" in FIG. 1), a power control unit (hereinafter referred to as "PCU") 12 as a power conversion device, a motor 13 (shown as "MG" in FIG. 1) as an electric load, and a vehicle ECU 14 (shown as "ECU" in FIG. 1). Note that PCU is an abbreviation for "Power Control Unit", MG is an abbreviation for "Motor Generator", and ECU is an abbreviation for "Electronic Control Unit".

[0014] The battery pack 11 is mounted on the vehicle 10 as a driving power source for the vehicle 10. In Fig. 1, the battery pack 11 is arranged, for example, in a front compartment. The battery pack 11 may also be arranged in the rear compartment, under a seat, under the floor, or the like.

[0015] The battery pack 11 includes a battery assembly 20, which will be described later, and is a chargeable and dischargeable DC voltage source. The battery pack 11 supplies power to an electrical load of the vehicle 10. The battery pack 11 also converts power via the PCU 12 and supplies the power to the motor 13. The battery pack 11 is also charged via the PCU 12.

[0016] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the motor 13 in accordance with a control signal from the vehicle ECU 14. The PCU 12 includes, for example, an inverter that converts a DC voltage from the battery pack 11 into an AC voltage to drive the motor 13, and a converter that boosts the DC voltage supplied to the inverter to an output voltage of the battery pack 11 or higher.

[0017] The motor 13 is an AC rotating electric machine, for example a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The motor 13 is driven by the PCU 12 to generate a rotational driving force, and the driving force generated by the motor 13 is transmitted to the driving wheels. On the other hand, when the vehicle 10 is braked, the motor 13 operates as a generator and performs regenerative power generation. The electric power generated by the motor 13 is supplied to the battery pack 11 via the PCU 12 and stored in the battery pack 20.

[0018] The vehicle ECU 14 includes a CPU, a ROM, a RAM, input / output ports for inputting and outputting various signals, etc. The CPU loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM describes the processing of the vehicle ECU 14. As an example of the main processing of the vehicle ECU 14, the vehicle ECU 14 receives information such as the voltage, current, SOC (State Of Charge), and SOH (State Of Health) of the battery pack 20 from the battery pack 11, and controls the PCU 12 to instruct the driving of the motor 13 and the charging and discharging of the battery pack 11.

[0019] <Battery pack> The battery pack 11 will be described in detail. Fig. 2 is a block diagram showing the configuration of the battery pack 11, and Fig. 3 is a perspective view showing a schematic configuration of the battery pack 11. The battery pack 11 includes a battery pack 20, a battery monitoring system 100, and a housing 50 (shown by a dashed line) that houses them. The battery monitoring system 100 is a system that monitors and manages the battery pack 20 using wireless communication. The battery monitoring system 100 includes a plurality of battery monitoring devices 30 and a battery control device 40, and wireless communication is performed between these. For this wireless communication, a frequency band used for short-range communication, such as the 2.4 GHz band or the 5 GHz band, is used.

[0020] <Battery pack> The assembled battery 20 includes a plurality of battery blocks 21 (sometimes referred to as battery stacks or battery modules). The assembled battery 20 is configured by connecting the plurality of battery blocks 21 in series and / or parallel. Each battery block 21 includes a plurality of battery cells 22. Each battery cell 22 is configured by a lithium ion secondary battery, a nickel-hydrogen secondary battery, or the like. The lithium ion secondary battery is a secondary battery that uses lithium as a charge carrier, and may include not only a general lithium ion secondary battery with a liquid electrolyte, but also a so-called all-solid-state battery that uses a solid electrolyte. The plurality of battery cells 22 are connected in series and / or parallel to configure the battery block 21. It is optional whether or not to provide the battery block 21, and the assembled battery 20 may be configured by connecting the plurality of battery cells 22 in series and / or parallel.

[0021] <Battery monitoring device> The battery monitoring device 30 will be described. Note that each battery monitoring device 30 has a common configuration. The battery monitoring device 30 is also called a satellite battery module (SBM), and is provided for each battery block 21, that is, for each of a plurality of battery cells 22. As shown in FIG. 2, each battery monitoring device 30 includes a monitoring IC 31, a child device side wireless IC 32, a child device side wireless antenna 33, and the like. The child device side wireless IC 32 is connected to the monitoring IC 31 by a wire. The child device side wireless IC 32 is connected to the child device side wireless antenna 33 by a wire.

[0022] The monitoring IC 31 is also called a cell supervising circuit (CSC), and acquires (senses) battery information of each battery cell 22 constituting the battery block 21 via a physical quantity detection sensor (not shown) or the like. The physical quantity detection sensor is, for example, a voltage sensor, a temperature sensor, a current sensor, or the like, and the battery information includes, for example, voltage information, temperature information, current information, and the like of each battery cell 22. Note that the object to be monitored by the battery monitoring device 30 may be the battery block 21 or the entire battery pack 20, and may be changed as desired.

[0023] When the monitoring IC 31 receives data (control data as control information) requesting acquisition and transmission of battery information, it acquires the battery information and transmits monitoring data (control result) including at least the battery information. The monitoring IC 31 may have a function of executing a fault diagnosis (self-diagnosis) of the circuit part of the battery monitoring device 30 including itself, and transmitting the monitoring data including the diagnosis result together with the acquired battery information.

[0024] The slave-side wireless IC 32 includes an RF circuit, a microcomputer, a front-end circuit, and the like (not shown) for wirelessly transmitting and receiving data. The slave-side wireless IC 32 has a transmission function of modulating data and oscillating at the frequency of an RF signal. In addition, the slave-side wireless IC 32 has a reception function of demodulating received data. RF is an abbreviation for "radio frequency."

[0025] The slave-side wireless IC 32 modulates the monitoring data including the battery information received from the monitoring IC 31 and transmits it to the battery control device 40 via the slave-side wireless antenna 33. At this time, the slave-side wireless IC 32 adds data necessary for wireless communication, such as communication control information, to the monitoring data including the battery information and transmits it. Data necessary for wireless communication is, for example, an identifier (ID) and an error detection code. The slave-side wireless IC 32 also has a function of determining the data size, communication format, and schedule of communication between the battery monitoring device 30 and the battery control device 40, a function of detecting errors, and the like.

[0026] Furthermore, the slave side wireless IC 32 receives and demodulates data wirelessly transmitted from the battery control device 40 via the slave side wireless antenna 33. When the slave side wireless IC 32 receives control data including a request to acquire and transmit battery information, for example, the slave side wireless IC 32 transmits (transfers) the control data via a wired connection to the monitoring IC 31. When the slave side wireless IC 32 receives monitoring data including battery information from the monitoring IC 31 in response to the request, the slave side wireless IC 32 modulates the monitoring data and wirelessly transmits it to the battery control device 40 via the slave side wireless antenna 33.

[0027] The slave side wireless antenna 33 converts the RF signal, which is an electrical signal, into radio waves and radiates it into space. The slave side wireless antenna 33 also receives the radio waves propagating through space and converts them into an electrical signal.

[0028] <Battery control device> The battery control device 40 is also called a battery ECU or a BMU (Battery Management Unit). The battery control device 40 is configured to be able to wirelessly communicate with each battery monitoring device 30.

[0029] 2, the battery control device 40 includes a battery control MCU 41, a parent device side wireless IC 42, and a parent device side wireless antenna 43. The parent device side wireless IC 42 is connected to the battery control MCU 41 by a wire. The parent device side wireless IC 42 is also connected to the parent device side wireless antenna 43 by a wire.

[0030] The battery control MCU 41 is composed of a microcontroller unit (microcontroller unit) including a CPU, ROM, RAM, an input / output interface, etc. The CPU of the battery control MCU 41 loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM describes processes related to battery control, etc.

[0031] As an example of the main processing, the battery control MCU 41 transmits control data to the battery monitoring device 30 to request acquisition and transmission of battery information. The battery control MCU 41 also performs various processing related to monitoring the assembled battery 20, the battery block 21, and the battery cells 22 based on the monitoring data including the battery information received from the battery monitoring device 30. For example, the battery control MCU 41 may transmit the monitoring result (monitoring data) to the vehicle ECU 14, which is a higher-level ECU. In this case, the battery control MCU 41 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 vehicle ECU 14. The battery control MCU 41 also controls a relay switch that switches between the energized and de-energized states of the assembled battery 20 and the PCU 12 or the motor 13 based on the monitoring result or the like. The battery control MCU 41 also may transmit an equalization signal that equalizes the voltage of each battery cell 22. In this embodiment, the vehicle ECU 14 issues instructions to the PCU 12 to control the charging and discharging of the battery pack 20, but the battery control MCU 41 may be configured to perform this function. As described above, the battery control MCU 41 monitors and manages the battery pack 20, the battery block 21, and the battery cells 22.

[0032] The master-side wireless IC 42 includes an RF circuit, a microcomputer, a front-end circuit, and the like (not shown) for wirelessly transmitting and receiving data, similar to the slave-side wireless IC 32. The master-side wireless IC 42 has a transmitting function and a receiving function, similar to the slave-side wireless IC 32.

[0033] The master unit side wireless IC 42 demodulates the received monitoring data including the battery information via the master unit side wireless antenna 43 and transmits the demodulated data to the battery control MCU 41. The master unit side wireless IC 42 also modulates the control data received from the battery control MCU 41 with data necessary for wireless communication such as communication control information, and transmits the modulated data to the battery monitoring device 30 via the master unit side wireless antenna 43. The data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code. The master unit side wireless IC 42 also has a function of determining the data size, communication format, schedule, and the like of the communication between the battery monitoring device 30 and the battery control device 40, a function of detecting errors, and the like.

[0034] The parent-side wireless antenna 43 has the same configuration and function as the child-side wireless antenna 33. That is, the parent-side wireless antenna 43 converts an RF signal, which is an electrical signal, into a radio wave and radiates it into space, and also receives the radio wave propagating through space and converts it into an electrical signal.

[0035] <Case> The housing 50 is made of a conductor such as metal. The housing 50 is formed in a metal box shape, and has a substantially rectangular parallelepiped shape. Note that a part or the whole may be made of a non-conductive material such as resin. The housing 50 houses the battery pack 20, the battery monitoring device 30, and the battery control device 40.

[0036] Here, the arrangement of the battery pack 20, the battery monitoring device 30, and the battery control device 40 will be briefly described with reference to Fig. 3. The bottom surface of the housing 50 serves as the mounting surface for the vehicle 10. As shown in Fig. 3, inside the substantially rectangular parallelepiped housing 50, a plurality of battery blocks 21 constituting the battery pack 20 are arranged side by side in the longitudinal direction (X direction in Fig. 3). In each battery block 21, the battery cells 22 constituting the battery block 21 are arranged so as to be stacked side by side in the lateral direction of the housing 50 (Y direction in Fig. 3).

[0037] The battery monitoring device 30 and bus bars 23 are arranged on the top surface of each battery block 21 (the surface on the Z+ direction side in FIG. 3) and fixed with screws or the like. The battery control device 40 is arranged at the very end in the longitudinal direction (X direction). In this case, it is attached to the side surface of one of the battery blocks 21 (the battery block 21 at the end in the X direction in this embodiment) so that the circuit board on which the battery control device 40 is arranged is vertical. Note that it is desirable to arrange the parent unit side wireless antenna 43 so that it protrudes from the top surface of the battery block 21.

[0038] The arrangement of the battery pack 20, the battery monitoring device 30, and the battery control device 40 shown in Fig. 3 is one example and may be changed as desired. In addition, in this embodiment, the battery pack 20 and the battery monitoring system 100 are housed inside the housing 50, but a part of them may be disposed outside the housing 50. Also, the housing 50 may not be provided, and the battery pack 20 and the like may be directly attached to a vehicle body frame or the like. That is, the vehicle body frame may replace the housing 50.

[0039] <Wireless communication> Next, wireless communication (wireless communication method) between the battery monitoring device 30 and the battery control device 40 will be described with reference to Figs. 4 to 6. Figs. 4 and 5 are diagrams showing an example of a communication sequence in data communication between the battery monitoring device 30 and the battery control device 40. This communication sequence is repeated at predetermined intervals or is performed according to a determined communication schedule. The battery monitoring device 30 and the battery control device 40 execute wireless communication programs stored in their respective storage devices (ROM, etc.), thereby carrying out each process.

[0040] 4 to 6, wireless communication between one battery monitoring device 30 and a battery control device 40 will be described. The battery monitoring device 30 to be communicated with is determined by a communication schedule or the like. In Figs. 4 to 6, the monitoring IC 31 is indicated as MIC31, the child device side wireless IC 32 is indicated as WIC32, the battery control MCU 41 is indicated as MCU41, and the parent device side wireless IC 42 is indicated as WIC42. Fig. 6 is a diagram showing an example of the connection establishment process (step S10) shown in Fig. 4.

[0041] As shown in FIG. 4, the slave side wireless IC 32 of the battery monitoring device 30 and the master side wireless IC 42 of the battery control device 40 execute a process for establishing a connection (step S10).

[0042] Here, the connection establishment process of step S10 will be described with reference to Fig. 6. As shown in Fig. 6, the master side wireless IC 42 of the battery control device 40 executes a scanning operation (slave detection operation) (step S11), and the slave side wireless IC 32 executes an advertising operation (connection information transmission operation) (step S12). The scanning operation may start earlier than the advertising operation, or at approximately the same timing. It may also start later than the advertising operation.

[0043] The advertising operation is an operation in which the slave wireless IC 32 transmits an advertisement packet (ADV_PKT) by broadcast communication in order to inform the master wireless IC 42 of the battery control device 40 of its existence. The advertisement packet includes ID information of the slave wireless IC 32 (the battery monitoring device 30) and the battery control device 40.

[0044] In this advertising operation, a communication channel for connection establishment is used among a plurality of communication channels. The communication channel is a frequency band used in short-distance communication, for example, a 2.4 GHz band, divided by a predetermined bandwidth (for example, 2 MHz), and in this embodiment, as shown in FIG. 7, it is divided into 40 channels, 0ch to 39ch. The communication channel for connection establishment is a predetermined communication channel (for example, 37ch to 39ch) among the 40 channels. Meanwhile, the channels other than the communication channel for connection establishment (for example, 0ch to 36ch) among the plurality of communication channels are communication channels for data transmission, which will be described later.

[0045] In the advertising operation, as shown in Fig. 8, advertisement packets are transmitted at predetermined intervals using multiple (three in this embodiment) communication channels for connection establishment. As a result, even if communication failure occurs in any of the communication channels for connection establishment, communication can be performed in the other communication channels for connection establishment. For this reason, the three communication channels for connection establishment are set with frequency bands as far apart as possible so as not to cause interference with each other (see Fig. 7). In addition, it is desirable to set the communication channels for connection establishment so as not to overlap with frequency bands used by other devices, etc.

[0046] Returning to the explanation of the connection establishment process, as shown in Fig. 6, when the master side wireless IC 42 of the battery control device 40 detects an advertisement packet, i.e., the slave side wireless IC 32, by a scan operation, it transmits a connection request (CONNECT_REQ) to the detected slave side wireless IC 32 (step S13).

[0047] Then, when the slave side wireless IC 32 receives the connection request, a wireless communication path connection is established between one of the battery monitoring devices 30 and the battery control device 40 (step S14). When the connection is established, the slave side wireless IC 32 of the battery monitoring device 30 stops transmitting advertisement packets. The slave side wireless IC 32 periodically transmits advertisement packets until the connection is established.

[0048] It should be noted that this connection establishment process is executed, for example, at startup. At startup refers to, for example, when operating power is supplied. In a configuration in which power is constantly supplied from the battery block 21, startup occurs during the manufacturing process of the vehicle 10 or after parts are replaced at a repair shop. Start-up may also occur when a startup signal such as an IG signal output when the ignition switch is turned on is input. For example, startup occurs when the ignition switch is switched from off to on by a user's operation. Also, when the ignition switch is turned off, the battery monitoring device 30 and the battery control device 40 are in a sleep state (standby mode), but are activated intermittently. The connection establishment process may also be executed during this intermittent startup.

[0049] Then, at the time of startup, a connection establishment process is executed between the battery control device 40 and all of the battery monitoring devices 30 that are targets for connection with the battery control device 40 in wireless communication.

[0050] Furthermore, when the battery monitoring device 30 and the battery control device 40 are disconnected, they again execute the connection establishment process (step S10). That is, they execute reconnection. The battery control device 40 executes reconnection (establishment of connection) with the disconnected battery monitoring device 30 while continuing data communication with the remaining battery monitoring devices 30 with which the connection has been established. For example, the disconnection occurs due to a deterioration in the communication environment.

[0051] Furthermore, once a wireless communication connection is established, the connection establishment process is skipped and the subsequent processes are performed unless the connection is disconnected. In other words, once a wireless communication connection is established in step S10, the battery control device 40 periodically performs data communication with the battery monitoring device 30 (the processes of steps S20 to S34).

[0052] More specifically, as shown in Fig. 4, the battery control MCU 41 of the battery control device 40 selects a battery monitoring device 30 to be a communication partner (step S20). The battery monitoring device 30 to be a communication partner is selected from among the battery monitoring devices 30 with which a connection has been established. In this embodiment, the communication partners are selected in a pre-scheduled order, but the selection method may be changed arbitrarily. Also, although the selection of the communication partner is performed by the battery control MCU 41, it may also be performed by the parent device side wireless IC 42.

[0053] Next, the battery control MCU 41 of the battery control device 40 transmits control data (control information) including an acquisition request and a transmission request for monitoring data including battery information to the battery monitoring device 30, which is to be the communication partner (step S21).

[0054] When the master wireless IC 42 receives the control data, it generates transmission data by adding data necessary for wireless communication, such as communication control information, to the control data (step S22). In this step S22, the master wireless IC 42 designates the battery monitoring device 30 to be the communication partner, and adds data necessary for wireless communication, such as communication control information, to the control data.

[0055] At the same time, the master wireless IC 42 selects one of the communication channels for data transmission (e.g., 0ch to 36ch) (step S23). At that time, as shown in Fig. 9, the master wireless IC 42 selects a communication channel from the usable communication channels for data transmission by referring to a channel map in which the status (state) of each communication channel is set to usable or unusable (unselectable, the same applies below). Note that a method for setting each communication channel to usable or unusable will be described later.

[0056] Then, the master side wireless IC 42 wirelessly transmits the transmission data to the slave side wireless IC 32 via the master side wireless antenna 43 (step S24). At that time, the master side wireless IC 42 wirelessly transmits the transmission data to the slave side wireless IC 32 using the selected communication channel for data transmission.

[0057] When the slave-side wireless IC 32 of the battery monitoring device 30 selected as the destination (communication partner) receives the transmission data via the slave-side wireless antenna 33, it determines whether the communication quality of the communication channel used to transmit the transmission data was good (step S25). In other words, the slave-side wireless IC 32 determines whether the transmission data was normally received.

[0058] In step S25, the slave side wireless IC 32 may determine that the communication quality is poor (cannot be normally received) if the received signal strength (RSSI: Received Signal Strength Indicator) is equal to or lower than a predetermined strength threshold. The slave side wireless IC 32 may determine the communication quality by, for example, CRC (Cyclic Redundancy Check). The slave side wireless IC 32 may determine the communication quality based on whether or not the packet error rate is equal to or lower than a predetermined error rate. The slave side wireless IC 32 may determine the communication quality based on the communication time from when the master side wireless IC 42 transmits data to when the slave side wireless IC 32 receives data. When the transmission data is divided into packets and transmitted, the slave side wireless IC 32 may determine the communication quality based on the variation in the interval from when one packet arrives to when the next packet arrives. The communication quality may be determined based on SNR (Signal to Noise Ratio). Also, other well-known methods may be adopted, or a combination of any of these methods may be used to determine the communication quality based on the results of these determinations.

[0059] If the communication quality is good, the determination result in step S25 is positive, and if the communication quality is poor, the determination result in step S25 is negative. If the determination result in step S25 is positive, that is, if the data is normally received, the slave side wireless IC 32 transmits the control data included in the received transmission data to the monitor IC 31 (step S26).

[0060] When the monitoring IC 31 receives the control data, it acquires (senses) battery information in accordance with the control data (step S27).The monitoring IC 31 may also perform fault diagnosis of the circuit.

[0061] Next, the monitoring IC 31 transmits monitoring data including the battery information to the slave side wireless IC 32 in accordance with the control data (step S28). At this time, the monitoring data including the diagnosis result may be transmitted together with the battery information.

[0062] When the slave side wireless IC 32 receives the monitoring data from the monitoring IC 31, it generates transmission data including the monitoring data, that is, response data, and wirelessly transmits (responses) the data to the master side wireless IC 42 via the slave side wireless antenna 33 (step S29). At this time, data necessary for wireless communication, such as communication control information, is added to the response data, as in the process of the master side wireless IC 42 in step S22. In addition, communication quality data (the determination result of step S25) is also added to the response data. In addition, the slave side wireless IC 32 selects the same communication channel as the communication channel used when receiving the transmission data transmitted by the master side wireless IC 42, and wirelessly transmits the data to the master side wireless IC 42. That is, the slave side wireless IC 32 transmits the data using the communication channel for data transmission selected in step S23. Therefore, the communication channel for data transmission corresponds to the communication channel for battery information transmission for transmitting and receiving battery information.

[0063] On the other hand, if the judgment result of step S25 is negative (if the communication quality is poor), the slave side wireless IC 32 proceeds to step S29 without having the monitoring IC 31 acquire the monitoring data (battery information), that is, without executing the processing of steps S26 to S28, and generates response data including communication quality data and the like excluding the monitoring data, and wirelessly transmits (responses) it to the master side wireless IC 42.

[0064] Even if the determination result in step S25 is negative (if the communication quality is poor), if the control data included in the transmission data can be read, the processes in steps S26 to S29 may be executed.

[0065] 5, after transmitting the transmission data in step S24, the master wireless IC 42 determines whether or not response data has been returned from the slave wireless IC 32, which is the communication partner (step S30). Specifically, after transmitting the transmission data in step S24, the master wireless IC 42 determines whether or not response data has been received before a predetermined time has elapsed.

[0066] If the result of this determination is negative, that is, if the response data cannot be received normally and it is determined that the communication quality is poor, the master side wireless IC 42 updates the channel map to reflect this fact (step S31).

[0067] Here, the update of the channel map in step S30 will be described. The channel map is stored in the master side wireless IC 42, and is configured to store the communication quality when each communication channel (ch0 to ch36) for data transmission is a communication partner for each battery monitoring device 30 (battery monitoring devices 30a to 30h in this embodiment) as shown in Fig. 9.

[0068] Then, in step S31, the master wireless IC 42 stores that the communication quality of the communication channel for data transmission selected in step S23 was poor when data was transmitted to the communication partner selected in step S20. For example, when the communication partner selected in step S20 is the battery monitoring device 30a and the communication channel for data transmission selected in step S23 is the communication channel ch1, the master wireless IC 42 stores "poor" in the column of the channel map corresponding to the communication channel ch1 and the battery monitoring device 30a in step S31. In this embodiment, when the communication quality data is poor, it is illustrated by "x" in FIG. On the other hand, when the communication quality data is not determined to be poor in FIG. 9, it is shown by a blank column.

[0069] In this embodiment, when the master wireless IC 42 stores that the communication quality is poor, it updates the channel map with the status of the communication channel as unavailable (restricted use) from the next time onwards. For example, when "poor" is stored in the field corresponding to the communication channel ch1 and the battery monitoring device 30a, the status of the communication channel ch1 is set to unavailable. As a result, the communication channel ch1 will not be selected in step S23 from the next time onwards. The master wireless IC 42 then ends the data communication for that period.

[0070] If the determination result in step S30 is positive, i.e., if response data has been returned, the master side wireless IC 42 determines whether the returned response data has been received normally (step S32). In step S32, the communication quality of the used communication channel is determined by performing the same process as in step S25. At the same time, the communication quality is determined based on the determination result of the communication quality included in the response data (the determination result in step S25). If the communication quality is determined to be poor by any of these, step S32 is determined to be negative, whereas if the communication quality is determined to be not poor by any of these, step S32 is determined to be positive.

[0071] If the determination result in step S32 is negative (if the communication quality is poor), the process proceeds to step S31. That is, if the communication quality is poor either when transmitting from the master side wireless IC 42 to the slave side wireless IC 32 or when replying from the slave side wireless IC 32 to the master side wireless IC 42, the process proceeds to step S31.

[0072] On the other hand, if the determination result in step S32 is positive, that is, if the data is normally received (if the communication quality is good), the master wireless IC 42 transmits the monitoring data included in the received response data to the battery control MCU 41 (step S33). The battery control MCU 41 executes a predetermined process based on the monitoring data (step S34). Then, the master wireless IC 42 ends the data communication in the period.

[0073] As described above, the battery control device 40 periodically performs the above-mentioned data communication with the battery monitoring device 30 with which a connection has been established. In this embodiment, the master side wireless IC 42 and the slave side wireless IC 32 function as a communication quality determination unit that determines and stores the communication quality for each of the communication channels for each of the battery monitoring devices with which the battery control device is communicating. The processes of steps S25, and S30 to S32 correspond to the communication quality determination process.

[0074] However, if the communication quality is judged to be poor, the communication channel used for communication is subsequently made unusable (restricted), but if this is repeated, the number of available communication channels will become too small. Therefore, if certain conditions are met, the restriction on use is lifted. The process of lifting the restriction on use will be described in detail below with reference to FIG. 10.

[0075] The usage restriction release process is periodically performed by the master-side wireless IC 42 upon startup of the battery monitoring system 100. For example, the process is performed when the ignition switch is turned on.

[0076] When the usage restriction release process is performed, first, the master wireless IC 42 refers to the channel map and determines whether the number of communication channels (usage restriction number) whose status is set to unavailable (usage restriction, the same applies below) is equal to or greater than a predetermined number (step S101). The predetermined number is an arbitrary number, but may be, for example, a value equal to or greater than half of the communication channels for data transmission (e.g., 20). The predetermined number may be all of the communication channels for data transmission (e.g., 37), or may be equal to or greater than two-thirds (e.g., 25 or more). If the determination result is negative, the process ends.

[0077] On the other hand, if the determination result in step S101 is positive, the master-side wireless IC 42 calculates the number of battery monitoring devices 30 whose communication quality has been determined to be "bad" for each of the communication channels that have been made unavailable (hereinafter, simply referred to as "total number of communication failures") (step S102). For example, in the channel map of FIG. 9, when communication channel ch1 is used, the number of battery monitoring devices 30 whose communication quality has been "bad" is 1, so "1" is calculated as the total number of communication failures. The same is true for communication channel ch12. Also, when communication channel ch23 is used, the number of battery monitoring devices 30 whose communication quality has been "bad" is 2, so "2" is calculated as the total number of communication failures. Also, when communication channel ch34 is used, the number of battery monitoring devices 30 whose communication quality has been "bad" is 3, so "3" is calculated as the total number of communication failures.

[0078] Next, the master wireless IC 42 evaluates each communication channel with a usage restriction based on the total number of communication failures, and releases the usage restriction of the communication channel according to the evaluation (step S103). In step S103, the master wireless IC 42 evaluates each communication channel with a usage restriction higher as the total number of communication failures decreases, and lowers the evaluation as the total number of communication failures increases, and releases the usage restriction by giving priority to the communication channel with a higher evaluation.

[0079] Specifically, the master-side wireless IC 42 changes the unavailability of a communication channel for which the total number of communication failures is less than a first threshold value to enable the use of the communication channel. In other words, the master-side wireless IC 42 releases the usage restriction on a communication channel for which the number of battery monitoring devices 30 determined to have poor communication quality is less than a first threshold value among a plurality of communication channels whose usage is restricted. In this embodiment, the first threshold value is set to "2". Therefore, the master-side wireless IC 42 enables the use of a communication channel for which the number of failures is less than "2".

[0080] For example, in the channel map of Fig. 9, the use restrictions of communication channels ch1 and ch12, whose total number of communication failures is "1", are lifted and made available for use. On the other hand, in the channel map of Fig. 9, the use restrictions of communication channels ch23 and ch34, whose total number of communication failures is "2" or "3", are not lifted and remain unavailable.

[0081] As described above, in this embodiment, the master wireless IC 42 functions as a restriction lifting unit that lifts the usage restriction of a communication channel and permits its use. The usage restriction lifting process corresponds to the restriction lifting process.

[0082] According to the above embodiment, the following effects can be obtained.

[0083] The master wireless IC 42 calculates the number of the battery monitoring devices whose communication quality is determined to be poor (total number of communication failures) for each communication channel whose use is restricted, performs an evaluation based on the total number of communication failures, and releases the usage restriction of the communication channel according to the evaluation. More specifically, the master wireless IC 42 evaluates each communication channel whose use is restricted higher as the total number of communication failures decreases, and evaluates the communication channel whose use is restricted lower as the total number of communication failures increases, and releases the usage restriction by giving priority to the communication channel with the higher evaluation.

[0084] Specifically, the master wireless IC 42 changes the unavailability of a communication channel for which the total number of communication failures is less than the first threshold value to an available communication channel, i.e., releases the usage restriction on a communication channel for which the number of battery monitoring devices 30 determined to have poor communication quality is less than the first threshold value among the multiple communication channels whose usage is restricted.

[0085] This allows preferentially releasing the restriction on communication channels with a small number of battery monitoring devices 30 with poor communication quality, and therefore makes it possible to prevent the restriction on use of communication channels with a high possibility of poor communication quality from being released in comparison with the case where the restriction is released uniformly depending on the passage of time or the like.

[0086] The timing (predetermined timing) at which the usage restriction is lifted is the timing when step S101 is answered in the affirmative, i.e., the timing when the usage of a predetermined number of communication channels among the multiple communication channels is restricted. This makes it possible to prevent the number of communication channels with communication restrictions from becoming too large, i.e., to prevent the number of selectable communication channels from becoming too small.

[0087] Furthermore, when the master wireless IC 42 determines that the communication quality is poor when communicating with any of the battery monitoring devices 30 as the communication partner of data communication, it restricts the use of the communication channel used at that time. In other words, the availability or unavailability of each communication channel is not set for each battery monitoring device 30. This simplifies management. In other words, there is no need to switch communication channels for each battery monitoring device 30, and the control burden can be reduced.

[0088] The master wireless IC 42 and the slave wireless IC 32 evaluate the communication quality in consideration of at least one of the radio wave intensity, the packet error rate, and the communication speed during communication, so that the communication quality can be appropriately evaluated.

[0089] Second embodiment A second embodiment in which a part of the configuration of the battery monitoring system 100 of the first embodiment is modified will be described.

[0090] In the use restriction release process of the second embodiment, if the use of a communication channel is restricted a specified number of times within a certain period of time, it is determined that a communication abnormality has occurred. Hereinafter, the use restriction release process of the second embodiment will be described with reference to FIG.

[0091] When the usage restriction removal process is performed, first, the master side wireless IC 42 performs the processes of steps S101 to S103, similarly to the first embodiment.

[0092] Next, the master wireless IC 42 adds 1 to the restriction release counter to update it (step S201). Then, the master wireless IC 42 determines whether the value of the restriction release counter is equal to or greater than the number of abnormality determinations (step S202). The number of abnormality determinations is an arbitrary number, but is, for example, "5."

[0093] If the result of this determination is positive, the master side wireless IC 42 determines that some abnormality has occurred in the wireless communication in the battery monitoring system 100, and notifies the ECU such as the vehicle ECU 14 of the occurrence of the abnormality (step S203). Then, the usage restriction release process is terminated.

[0094] On the other hand, if the determination result in step S101 is negative, or if the determination result in step S202 is negative, the master side wireless IC 42 determines whether the value of the timer, which starts after the value of the restriction release counter becomes 1 from 0 (initial value), is equal to or greater than a predetermined time (step S204). If the determination result is positive, the restriction release counter is initialized (step S205), whereas if negative, the value of the restriction release counter is maintained (step S206). Then, the usage restriction release process is terminated. That is, the restriction release counter is initially incremented by 1 and then initialized (set to an initial value of "0") after a predetermined time has elapsed. This predetermined time may be any period, for example, "30 minutes." Therefore, if step S103 (removal of usage restriction) of the usage restriction release process is performed a number of times equal to or greater than the abnormality determination number within the predetermined time (for example, within 30 minutes) after the usage restriction is first released, it is determined that there is an abnormality, and if the number of times step S103 is performed is less than the abnormality determination number, it is not determined that there is an abnormality. As described above, in the second embodiment, the master side wireless IC 42 functions as an abnormality determination unit.

[0095] According to the second embodiment, when the use restriction is frequently and repeatedly released within a certain period of time, that is, when the number of communication channels that are frequently restricted from use increases, it is determined that some abnormality has occurred in the communication and a notification can be sent. In other words, when the number of use restrictions frequently exceeds a predetermined number even after the use restriction is repeatedly released, it is determined that a communication abnormality has occurred and a notification can be sent.

[0096] Third embodiment A third embodiment in which the configuration of the battery monitoring system 100 of the first embodiment is partially modified will be described.

[0097] In wireless communication, the shorter the communication distance, the easier the communication and the better the communication quality. Conversely, the longer the communication distance, the more difficult the communication. Therefore, a communication channel with poor communication quality despite a short communication distance can be said to have a low rating. For this reason, it is desirable not to lift restrictions on the use of such communication channels.

[0098] Therefore, the master side wireless IC 42 of the third embodiment evaluates each communication channel taking into consideration the number of battery monitoring devices 30 whose communication quality has been determined to be poor and the positional relationship between the battery control device 40 and the battery monitoring device 30 with which it communicates. Hereinafter, a description will be given based on Figs. 12 and 13.

[0099] First, data communication in the third embodiment will be described. Fig. 12 shows an example of a communication sequence in the third embodiment. In Fig. 12, the processes of steps S10, and S20 to S30 are carried out in the same manner as in the first embodiment.

[0100] As shown in FIG. 12, if the determination result in step S30 is negative (if the response data has not been received normally) or if the determination result in step S32 is negative (if the communication quality is poor), the master side wireless IC 42 updates the channel map (step S301).

[0101] A channel map updating method (processing of step S301) in the third embodiment will be described in detail. The channel map in the third embodiment is stored in the master side wireless IC 42, and is configured to store a negative evaluation score (negative evaluation score) for each communication channel (ch0 to ch36) for data transmission based on the communication quality when each battery monitoring device 30 (battery monitoring devices 30a to 30h in this embodiment) becomes a communication partner, as shown in Fig. 13.

[0102] The negative score is determined based on whether the communication quality is poor and on the positional relationship between the battery control device 40 and the battery monitoring device 30 that is the communication partner. Specifically, when the communication quality is poor when the battery monitoring device 30a-30d that is relatively close to the battery control device 40 among all the battery monitoring devices 30a-30h becomes the communication partner among all the battery monitoring devices 30a-30h, the negative score is set to "2". On the other hand, when the communication quality is poor when the battery monitoring device 30e-30h that is relatively long from the battery control device 40 becomes the communication partner, the negative score is set to "1". In other words, even though the shorter the communication distance, the less likely the communication quality is to become poor, if the communication quality becomes poor, the evaluation is lowered (i.e., the negative score is larger).

[0103] For example, when the communication partner selected in step S20 is the battery monitoring device 30a, if the communication quality of the communication channel ch1 for data transmission selected in step S23 is poor, as shown in Figure 13, the parent unit side wireless IC 42 stores "2" as a negative score in the field corresponding to the communication channel ch1 and the battery monitoring device 30a.

[0104] In this embodiment, when the master wireless IC 42 stores that the communication quality is poor, that is, when the master wireless IC 42 stores a negative score of "1" or "2", the status of the communication channel is updated to "unusable" (restricted use) in the channel map from the next time onwards. That is, the communication channel ch1 will not be selected in the next and subsequent data communications.

[0105] On the other hand, when the communication partner selected in step S20 is the battery monitoring device 30g, if the communication quality of the communication channel ch12 for data transmission selected in step S23 is poor, the master-side wireless IC 42 stores "1" as the poor score in the field corresponding to the communication channel ch12 and the battery monitoring device 30g, as shown in Fig. 13. In this case as well, the communication channel ch12 will not be selected in the next and subsequent data communications.

[0106] When the channel map update is completed, the master wireless IC 42 ends data communication for that period.

[0107] If the determination result in step S32 is positive, that is, if the signal is received normally (if the communication quality is good), the master side wireless IC 42 performs the processes of steps S33 to S34 in the same manner as in the first embodiment, and ends the data communication in that period.

[0108] Next, the use restriction release process in the third embodiment will be described with reference to FIG.

[0109] 14, first, the master wireless IC 42 refers to the channel map and determines whether the number of communication channels whose status is disabled (usage limit number) is equal to or greater than a predetermined number (step S311), in the same manner as in step S101 in the first embodiment. If the determination result is negative, the process ends.

[0110] On the other hand, when the determination result of step S311 is positive, the master-side wireless IC 42 sums up the negative evaluation scores for each of the communication channels that are disabled, and calculates a total score (step S312). For example, in the channel map of FIG. 13, the total negative evaluation scores corresponding to the communication channel ch1 is "2", so the total score is calculated as "2". On the other hand, the total negative evaluation scores corresponding to the communication channel ch12 is "1", so the total score is calculated as "1". In addition, in the communication channel ch23, the negative evaluation score "2" is stored in the battery monitoring device 30b, and the negative evaluation score "1" is stored in the battery monitoring device 30g, so the total score is calculated as "3". In addition, in the communication channel ch34, the negative evaluation score "1" is stored in the battery monitoring device 30g, and the negative evaluation score "1" is stored in the battery monitoring device 30h, so the total score is calculated as "2".

[0111] Next, the master wireless IC 42 changes the unusable state of the communication channels whose total score is less than the third threshold value to the usable state (step S313). The use restriction is maintained for the communication channels whose total score is high, i.e., the total number of negative evaluation points is large, while the use restriction is lifted for the communication channels whose total score is low (the total number of negative evaluation points is small). In this embodiment, the third threshold value is set to "2". Therefore, the communication channels whose total score is less than "2" are made usable.

[0112] For example, in the channel map of Fig. 13, the usage restriction of communication channel ch12 with a total score of "1" is lifted and made available for use. On the other hand, in the channel map of Fig. 13, the usage restriction of communication channel ch1 with a total score of "2" is not lifted and remains unavailable. In other words, even if the number of child devices with poor communication quality (total number of poor communication) is the same (1 device), the usage restriction is not lifted for those with close communication distances, while the usage restriction is lifted for those with far communication distances.

[0113] In addition, in the channel map of Fig. 13, the usage restrictions are not lifted for communication channels ch23 and ch34, which have a total score of "2" or "3", and the channels remain unavailable. In other words, if there are multiple child devices with poor communication quality (total number of poor communication), the usage restrictions are not lifted.

[0114] According to the third embodiment, the following effects can be obtained.

[0115] The parent unit side wireless IC 42 evaluates each communication channel taking into consideration the number of battery monitoring devices 30 evaluated as having poor communication quality and the positional relationship between the battery control device 40 and the battery monitoring device 30 with which it communicates, and based on the evaluation, lifts the usage restriction on one of the multiple communication channels whose usage is restricted.

[0116] Specifically, when the communication quality is determined to be poor, the parent wireless IC 42 stores a negative score according to the communication distance. At that time, the parent wireless IC 42 stores the negative scores by distinguishing between the communication channel used and the battery monitoring device 30 that is the communication partner. Then, at a predetermined timing, the parent wireless IC 42 calculates the total negative score for each communication channel, and releases the usage restriction on the communication channels whose total score is less than a third threshold value.

[0117] This makes it possible to determine the communication channel for which the usage restriction is lifted, taking into consideration the positional relationship between the battery monitoring device 30 and the battery control device 40, specifically, the communication distance. More specifically, when the number of battery monitoring devices 30 determined to have poor communication quality is one, the master side wireless IC 42 can lift the usage restriction, taking into consideration that communication quality is likely to deteriorate if the communication distance is long, but can not lift the usage restriction if the communication distance is short.

[0118] (Modification) The configuration of the battery monitoring system 100 of the above embodiment may be partially modified. Modifications will be described below.

[0119] In the above embodiment, if the determination result in step S32 is positive, i.e., if the response data has been received normally, the master wireless IC 42 may update the channel map to reflect that fact. In more detail, the master wireless IC 42 stores (overwrites) the fact that the communication quality of the communication channel for data transmission selected in step S23 was not poor when data was transmitted to the communication partner selected in step S20.

[0120] For example, when the communication partner selected in step S20 is the battery monitoring device 30a and the communication channel selected in step S23 is communication channel ch1, the master side wireless IC 42 stores in the field of the channel map corresponding to communication channel ch1 and the battery monitoring device 30a that the channel was not defective. In other words, if an "x" or a negative score of "1" or "2" indicating a defect is stored in the field of the channel map corresponding to communication channel ch1 and the battery monitoring device 30a, the field is erased and overwritten to become blank (a value indicating a non-defective field).

[0121] In step S102 of the first embodiment, the master wireless IC 42 may count the number of battery monitoring devices 30 whose communication quality has not been determined to be "poor". Then, in step S103, the master wireless IC 42 may change the unusability of a communication channel for which the number of battery monitoring devices 30 whose communication quality has not been determined to be "poor" is equal to or greater than a second threshold, and make the communication channel usable. The second threshold is an arbitrary value, but may be a value obtained by subtracting 1 or 2 from the number of battery monitoring devices 30.

[0122] In the above embodiment, the first to third thresholds may be changed according to the communication speed or the vehicle state. For example, the master wireless IC 42 may increase the first or third threshold (or decrease the second threshold) when the vehicle speed as the vehicle state is equal to or higher than a predetermined speed. As a result, when the vehicle 10 moves at high speed, vibrations transmitted from the vehicle 10 to the battery pack 11 increase, and deterioration of the communication quality (communication environment) is predicted, the usage restriction can be lifted taking the situation into consideration. The vehicle speed may be obtained directly from the vehicle speed sensor or indirectly via the battery control MCU 41.

[0123] Furthermore, the master side wireless IC 42 may increase the first threshold or the third threshold (or decrease the second threshold) when the communication speed is set to a predetermined value or higher. In other words, since the possibility that the communication quality will be poor increases when the communication speed is increased, the usage restriction can be lifted taking that circumstance into consideration.

[0124] Furthermore, when the vehicle 10 is traveling in an environment with a lot of external noise, for example, when the vehicle 10 is traveling near a radio tower, the master wireless IC 42 may change the first threshold value or the third threshold value to increase (or decrease the second threshold value). In this way, when a deterioration in communication quality (communication environment) is predicted due to traveling in an environment with a lot of external noise, the master wireless IC 42 can release the usage restriction taking into consideration the situation. Note that whether or not the vehicle 10 is traveling in an environment with a lot of external noise may be obtained indirectly via the battery control MCU 41, or the external noise may be measured directly.

[0125] As described above, in consideration of the fact that communication quality may change depending on the communication speed or the vehicle state, the first to third thresholds may be changed depending on the communication speed or the vehicle state. This makes it possible to appropriately set the communication channel to be released from use.

[0126] In the above embodiment, if the communication quality is found to be poor multiple times in data communication with any of the battery monitoring devices 30, the use of that communication channel may be restricted. Furthermore, if the communication quality is poor in data communication with two or more different battery monitoring devices 30 in any of the communication channels, the use of that communication channel may be restricted.

[0127] In the above embodiment, it is possible to restrict the use of only the communication channel for data communication (for sending and receiving battery information), but the communication channel for establishing a connection (for non-battery information) may also be restricted or released in the same manner. The communication channel for establishing a connection may also be used as a communication channel for sending and receiving battery information.

[0128] In the above embodiment, even if the communication error rate increases during use (power supply) of the assembled battery 20, it is desirable to monitor the transition of the battery state by increasing the frequency of obtaining battery information. Therefore, the parent-side wireless IC 42 as a restriction release unit may release the usage restriction at a predetermined timing when electricity is flowing between the battery pack 11 (the assembled battery 20) and the electric load. The electric load is, for example, an electric load to which power is supplied from the battery pack 11, such as the motor 13 or an air conditioner. When electricity is flowing, for example, a relay switch (system main relay) that switches between power supply and power cut-off between the battery pack 11 and the electric load is turned on. At this time, the parent-side wireless IC 42 may execute the usage restriction release process at predetermined intervals. As a result, during use (power supply) of the assembled battery 20, the frequency of obtaining battery information may be increased, and the transition of the battery state may be appropriately monitored.

[0129] In the above embodiment, when the battery pack 20 is not being used, there is no need to increase the frequency of obtaining battery information to the extent that it increases the communication error rate. Therefore, the parent device wireless IC 42 as a restriction release unit does not need to perform usage restriction release processing while the battery pack 11 (the battery pack 20) ​​is being charged. Charging the battery pack 11 does not only include charging by regenerative power generation of the motor 13, but also charging from an external charging device.

[0130] Furthermore, the master wireless IC 42 may not need to perform the use restriction release process while the battery pack 11 is in standby mode. The battery pack 11 is in standby mode, for example, when the ignition switch is turned off and the power supply monitoring system is in a sleep state. The standby mode may be implemented when the vehicle is stopped (including when temporarily stopped). This can suppress the communication error rate and reduce power consumption.

[0131] In step S32 of the first embodiment, if the communication quality is "good", a value indicating that may be stored in the channel map. Then, in the usage restriction release process, if the number of battery monitoring devices 30 with "good" communication quality is equal to or greater than a predetermined threshold, the usage restriction may be released preferentially.

[0132] In step S32 of the third embodiment described above, if the communication quality is determined to be “good”, an evaluation score (positive evaluation score) that takes into account the positional relationship between the battery control device 40 and the battery monitoring device 30 with which it communicates may be stored in the channel map.

[0133] The evaluation score is determined based on whether the communication quality is good and on the positional relationship between the battery control device 40 and the battery monitoring device 30 that is the communication partner. Specifically, when the communication quality is good when the battery monitoring device 30a-30d that is relatively close to the battery control device 40 among all the battery monitoring devices 30a-30h becomes the communication partner, the evaluation score is set to "1". On the other hand, when the communication quality is good when the battery monitoring device 30e-30h that is relatively long from the battery control device 40 becomes the communication partner, the evaluation score is set to "2". In other words, when the communication quality becomes good, even though it is supposed that the communication quality is less likely to become good as the communication distance becomes longer, the evaluation is higher (i.e., the evaluation score becomes larger).

[0134] In the use restriction removal process, the use restriction may be preferentially removed when the total score of the evaluation points is equal to or greater than a predetermined threshold value. This allows the use restriction of a communication channel that has a good communication distance to be preferentially removed, even if the communication distance is long.

[0135] The method of determining the evaluation points may be changed arbitrarily, and the stages of the evaluation points may be set finely according to the communication distance. For example, the evaluation points may be set from "1" to "8" in order from the shortest communication distance. That is, when the battery monitoring device 30a becomes the communication partner and the communication quality is good, the evaluation point may be set to "1", when the battery monitoring device 30b becomes the communication partner and the communication quality is good, the evaluation point may be set to "2", and when the battery monitoring device 30h becomes the communication partner and the communication quality is good, the evaluation point may be set to "8".

[0136] In the third embodiment, when the communication quality is poor when the battery monitoring devices 30a to 30d become the communication partner, the negative score is set to "2", and when the communication quality is poor when the battery monitoring devices 30e to 30h become the communication partner, the negative score is set to "1". As another example, the stages of the negative score may be set finely according to the communication distance. For example, the negative scores may be set from "8" to "1" in order from the shortest communication distance. That is, when the communication quality is poor when the battery monitoring device 30a becomes the communication partner, the negative score may be set to "8", when the communication quality is poor when the battery monitoring device 30b becomes the communication partner, the negative score may be set to "7", and when the communication quality is poor when the battery monitoring device 30h becomes the communication partner, the negative score may be set to "1".

[0137] In the above embodiment, the negative score or the evaluation point is added, but it may be subtracted. For example, as shown in FIG. 15, an evaluation point (positive evaluation) is set in advance for each battery monitoring device 30 in each communication channel of the channel map. Specifically, the battery monitoring devices 30a and 30b with the shortest communication distance are set as an evaluation point of "1", the battery monitoring device 30g with the second longest communication distance is set as an evaluation point of "2", and the battery monitoring device 30h with the longest communication distance is set as an evaluation point of "3". For convenience of explanation, the battery monitoring devices 30c to 30f are omitted in FIG. 15.

[0138] If the master wireless IC 42 determines that the communication quality is poor, it erases the evaluation points it has and sets them to zero.

[0139] Specifically, when the communication partner is the battery monitoring device 30a and the selected communication channel for data transmission is communication channel ch1, if the communication quality is determined to be poor, the master-side wireless IC 42 erases the evaluation score "1" in the column corresponding to communication channel ch1 and battery monitoring device 30a in the channel map to set it to zero. Similarly, when the communication partner is the battery monitoring device 30g and the selected communication channel for data transmission is communication channel ch2, if the communication quality is determined to be poor, the master-side wireless IC 42 erases the evaluation score "2" in the column corresponding to communication channel ch1 and battery monitoring device 30a in the channel map to set it to zero. Note that when the evaluation score is set to zero (if the communication quality is determined to be poor), the communication channel is made unusable.

[0140] In the use restriction removal process, the evaluation points for each communication channel with use restriction are totaled, and if the total score is equal to or greater than a threshold, the use restriction may be removed. For example, if the total score is equal to or greater than a threshold "6," the use restriction may be removed. In the channel map of FIG. 13, the use restriction on communication channel ch1 is removed.

[0141] In the above embodiment, when an abnormality occurs in the vehicle 10, the conditions for releasing the usage restriction may be relaxed. The abnormality in the vehicle 10 refers to an abnormality such as an abnormality in the battery temperature that requires the vehicle 10 to stop on the roadside by taking an evacuation route. Relaxing the release conditions means, for example, increasing the first threshold value or the third threshold value (for example, to "3") or decreasing the second threshold value. Also, the predetermined number in step S101 may be decreased. This allows the number of communication channels for which the usage restriction is released to be increased. That is, when an abnormality occurs, it is desirable to monitor the transition of the battery state by increasing the frequency of obtaining battery information, even if the communication error rate increases and the power consumption increases. Therefore, the release conditions are relaxed to increase the number of communication channels that can be used. Note that communication channels with usage restrictions may be uniformly released.

[0142] In the above embodiment, the communication channel may be selected by the battery control MCU 41. In this case, a channel map is stored on the battery control MCU 41 side, and the battery control MCU 41 manages information related to usage restrictions, etc., instead of the parent device side wireless IC 42. In the third embodiment and its modified example, the negative score (or evaluation score) was set based on the communication distance. Here, the communication distance is not limited to the straight-line distance between the parent-side wireless antenna 43 of the battery control device 40 and the child-side wireless antenna 33 of the battery monitoring device 30 with which it communicates. If there is an obstacle between the parent-side wireless antenna 43 and the child-side wireless antenna 33, the communication distance is the shortest distance in the wireless communication path along which radio waves travel, taking into account reflected waves. In the above embodiment, the connection establishment process (step S10) may be executed when the battery pack 11 is receiving power from an external charging device outside the vehicle. In this case, the external charging device and the battery monitoring device 30 may execute the connection establishment process instead of the battery control device 40, and data communication may be performed between the external charging device and the battery monitoring device 30. In other words, the external charging device may obtain and monitor battery information of the battery cells 22 instead of the battery control device 40.

[0143] The control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0144] Characteristic configurations extracted from each of the above-described embodiments will be described below.

[0145] [Configuration 1] A battery monitoring system (100) for monitoring battery units (20, 21, 22), comprising: a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels; a plurality of battery monitoring devices (30) that acquire battery information of the battery unit in accordance with the control information and return the battery information by wireless communication, a communication quality determination unit (32, 42) that determines and stores the communication quality of each of the communication channels for each of the battery monitoring devices that is a communication partner; a restriction removal unit (42) that calculates, at a predetermined timing, the number of the battery monitoring devices whose communication quality has been determined to be poor, or the number of the battery monitoring devices whose communication quality has not been determined to be poor, for each communication channel, evaluates each of the communication channels based on the calculated numbers, and lifts the usage restriction on any of the multiple communication channels whose usage has been restricted in accordance with the evaluation, thereby allowing its use.

[0146] [Configuration 2] The battery monitoring system of configuration 1, wherein the restriction lifting unit, at the specified timing, lifts the usage restriction for a communication channel among the multiple communication channels whose use is restricted and for which the number of battery monitoring devices whose communication quality is determined to be poor is less than a first threshold, or for a communication channel for which the number of battery monitoring devices whose communication quality is not determined to be poor is equal to or greater than a second threshold, to permit its use.

[0147] [Configuration 3] 3. The battery monitoring system according to claim 2, wherein the first threshold or the second threshold is changed depending on a communication speed or a vehicle state.

[0148] [Configuration 4] 4. The battery monitoring system according to any one of configurations 1 to 3, wherein the predetermined timing is a timing at which use of a predetermined number of communication channels among a plurality of communication channels is restricted.

[0149] [Configuration 5] A battery monitoring system according to any one of configurations 1 to 4, comprising a communication abnormality determination unit (42) that determines that a communication abnormality has occurred if the usage restriction on the communication channel is lifted a specified number of times within a certain period of time.

[0150] [Configuration 6] A battery monitoring system as described in any one of configurations 1 to 5, further comprising a restriction setting unit (42) that restricts the use of a communication channel that has been determined by the communication quality determination unit to have poor communication quality a predetermined number of times when any one of the plurality of battery monitoring devices becomes a communication partner.

[0151] [Configuration 7] A battery monitoring system described in any one of configurations 1 to 6, wherein the restriction lifting unit is capable of lifting the usage restriction at the predetermined timing when electricity is flowing between the battery unit and the electrical load.

[0152] [Configuration 8] 8. The battery monitoring system according to any one of configurations 1 to 7, wherein the restriction lifting unit does not lift the usage restriction while the battery unit is being charged and while the battery unit is in a standby mode.

[0153] [Configuration 9] A battery monitoring system described in any of configurations 1 to 8, wherein the restriction lifting unit, when an abnormality occurs in a vehicle in which the battery monitoring system is installed, relaxes the lifting conditions for lifting the usage restrictions, and lifts the usage restrictions on the multiple communication channels whose usage is restricted.

[0154] [Configuration 10] The battery monitoring system of configuration 1, wherein the restriction lifting unit evaluates each of the communication channels taking into consideration the number of the battery monitoring devices whose communication quality has been determined to be poor, or the number of the battery monitoring devices whose communication quality has not been determined to be poor, and the positional relationship between the battery control device and the battery monitoring device with which it communicates.

[0155] [Configuration 11] 11. The battery monitoring system according to any one of configurations 1 to 10, wherein the communication quality determination unit evaluates communication quality in consideration of at least one of radio wave intensity, a packet error rate, and a communication speed during communication.

[0156] [Configuration 12] A wireless communication program implemented by a battery monitoring system (100) for monitoring a battery unit (20, 21, 22), the battery monitoring system including a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices (30) that acquire battery information of the battery unit in accordance with the control information and return the battery information by wireless communication, the program comprising: a communication quality determination process for determining and storing a communication quality for each of the communication channels with respect to each of the battery monitoring devices that is a communication partner; a restriction lifting process for calculating, at a predetermined timing, for each communication channel, the number of the battery monitoring devices whose communication quality has been determined to be poor or the number of the battery monitoring devices whose communication quality has not been determined to be poor, evaluating each of the communication channels based on the numbers, and lifting the usage restriction on one of the multiple communication channels whose usage has been restricted in accordance with the evaluation, thereby allowing its use.

[0157] [Configuration 13] A wireless communication method implemented by a battery monitoring system (100) that monitors a battery unit (20, 21, 22), the battery monitoring system including a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices (30) that acquire battery information of the battery unit according to the control information and return the battery information by wireless communication, the method comprising: a communication quality determination process for determining and storing a communication quality for each of the communication channels with respect to each of the battery monitoring devices that is a communication partner; a restriction lifting process for calculating, at a predetermined timing, for each communication channel, the number of the battery monitoring devices whose communication quality has been determined to be poor or the number of the battery monitoring devices whose communication quality has not been determined to be poor, evaluating each of the communication channels based on the numbers, and lifting the usage restriction on one of the multiple communication channels whose usage has been restricted in accordance with the evaluation, to permit its use. [Explanation of symbols]

[0158] 20... battery pack, 21... battery block, 22... battery cell, 30... battery monitoring device, 31... monitoring IC, 32... child device side wireless IC, 40... battery control device, 42... parent device side wireless IC, 100... battery monitoring system, 41... battery control MCU.

Claims

1. A battery monitoring system (100) for monitoring battery units (20, 21, 22), comprising: a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels; a plurality of battery monitoring devices (30) that acquire battery information of the battery unit according to the control information and return the battery information by wireless communication, a communication quality determination unit (32, 42) that determines and stores the communication quality of each of the communication channels for each of the battery monitoring devices that are communication partners; a restriction removal unit (42) that calculates, at a predetermined timing, the number of the battery monitoring devices whose communication quality has been determined to be poor, or the number of the battery monitoring devices whose communication quality has not been determined to be poor, for each communication channel, evaluates each of the communication channels based on the calculated numbers, and lifts the usage restriction on one of the multiple communication channels whose usage has been restricted in accordance with the evaluation, thereby allowing its use.

2. The battery monitoring system of claim 1, wherein the restriction lifting unit lifts the usage restriction and allows use of a communication channel among the multiple communication channels whose use is restricted at the specified timing, for which the number of battery monitoring devices whose communication quality has been determined to be poor is less than a first threshold, or for which the number of battery monitoring devices whose communication quality has not been determined to be poor is equal to or greater than a second threshold.

3. The battery monitoring system according to claim 2 , wherein the first threshold or the second threshold is changed depending on a communication speed or a vehicle state.

4. The battery monitoring system according to claim 1 , wherein the predetermined timing is a timing at which use of a predetermined number of communication channels among a plurality of communication channels is restricted.

5. 5. The battery monitoring system according to claim 4, further comprising a communication anomaly determination unit (42) that determines that a communication anomaly has occurred if the usage restriction on the communication channel is lifted a specified number of times within a certain period of time.

6. A battery monitoring system as described in any one of claims 1 to 5, further comprising a restriction setting unit (42) that restricts the use of a communication channel that has been determined by the communication quality determination unit to have poor communication quality a predetermined number of times when one of the plurality of battery monitoring devices becomes a communication partner.

7. A battery monitoring system as described in any one of claims 1 to 5, wherein the restriction release unit is capable of releasing the usage restriction at the specified timing when electricity is flowing between the battery unit and the electrical load.

8. 6. The battery monitoring system according to claim 1, wherein the restriction lifting section does not lift the usage restriction while the battery section is being charged and while the battery section is in a standby mode.

9. A battery monitoring system as described in any one of claims 1 to 5, wherein the restriction lifting unit, when an abnormality occurs in a vehicle in which the battery monitoring system is installed, relaxes the lifting conditions for lifting the usage restrictions, and lifts the usage restrictions on the multiple communication channels whose usage is restricted.

10. The battery monitoring system of claim 1, wherein the restriction lifting unit evaluates each of the communication channels taking into account the number of the battery monitoring devices whose communication quality has been determined to be poor, or the number of the battery monitoring devices whose communication quality has not been determined to be poor, and the positional relationship between the battery control device and the battery monitoring device with which it communicates.

11. The battery monitoring system according to any one of claims 1 to 5, wherein the communication quality determination unit evaluates the communication quality taking into consideration at least one of radio wave strength, packet error rate, and communication speed during communication.

12. A wireless communication program implemented by a battery monitoring system (100) that monitors a battery unit (20, 21, 22) includes a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices (30) that acquire battery information of the battery unit according to the control information and return the battery information by wireless communication, a communication quality determination process for determining and storing a communication quality for each of the communication channels with respect to each of the battery monitoring devices that is a communication partner; a restriction lifting process for calculating, at a predetermined timing, for each communication channel, the number of the battery monitoring devices whose communication quality has been determined to be poor or the number of the battery monitoring devices whose communication quality has not been determined to be poor, evaluating each of the communication channels based on the numbers, and lifting the usage restriction on one of the multiple communication channels whose usage has been restricted in accordance with the evaluation, thereby allowing its use.

13. A wireless communication method implemented by a battery monitoring system (100) that monitors a battery unit (20, 21, 22), the battery monitoring system including a battery control device (40) that transmits control information by wireless communication using a communication channel selected from a plurality of available communication channels, and a plurality of battery monitoring devices (30) that acquire battery information of the battery unit according to the control information and return the battery information by wireless communication, a communication quality determination process for determining and storing a communication quality for each of the communication channels with respect to each of the battery monitoring devices that is a communication partner; a restriction lifting process for calculating, at a predetermined timing, for each communication channel, the number of the battery monitoring devices whose communication quality has been determined to be poor or the number of the battery monitoring devices whose communication quality has not been determined to be poor, evaluating each of the communication channels based on the numbers, and lifting the usage restriction on one of the multiple communication channels whose usage has been restricted in accordance with the evaluation, to permit its use.

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