Battery Monitoring System

Abstract

To monitor the frequency of a second clock signal of a battery monitoring device.SOLUTION: A battery monitoring system 100 includes a battery monitoring ECU 10 and a plurality of battery monitoring devices 30. The battery monitoring ECU includes a first clock generation unit 12 and a transmitting / receiving unit 16 that outputs a superimposed signal in which battery monitoring information is superimposed on a first clock signal and receives a monitoring result of a battery state. Each of the battery monitoring devices includes: a receiving unit 42 that receives the superimposed signal; a second clock generation unit 50; a control unit 48 that generates a reference clock signal from the superimposed signal and restores the battery monitoring information; a battery monitoring unit 54 that monitors the battery state using a second clock signal and the battery monitoring information; a frequency monitoring unit 53 that monitors the difference between the frequency of the reference clock signal and the frequency of the second clock signal; and a transmitting unit 44 that outputs the battery monitoring information, monitoring results at each stage up to the current stage, and differential information indicating the difference at each stage up to the current stage to the subsequent stage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a battery monitoring system. [Background technology]

[0002] In recent years, the number of automobiles using secondary batteries has been increasing. There is an increasing demand for a battery monitoring system (Battery Management System: BMS) that acquires the internal state of a secondary battery, including the remaining capacity (State of Charge: SOC) of the secondary battery, by measuring the electrical characteristics of the secondary battery. Patent Document 1 discloses a battery monitoring system in which a plurality of batteries are monitored by a plurality of battery monitoring ICs and the plurality of battery monitoring ICs are daisy-chained. In such a battery monitoring system, a battery monitoring ECU that controls the entire system is provided, and when an instruction or the like is output from the battery monitoring ECU to a first-stage battery monitoring device, each of the plurality of battery monitoring devices connected in the daisy chain adds its own data or the like to the information received from the previous stage and sends it to the subsequent stage. The battery monitoring device in the final stage outputs all the information to the battery monitoring ECU. Each battery monitoring device is provided with an oscillator and measures and monitors the battery using its oscillation frequency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-53579 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this case, in order to measure the state of each battery with high accuracy, it is necessary to set the accuracy of the oscillator frequency of each battery monitoring device, which requires the use of a high-accuracy oscillator such as a quartz crystal oscillator as the oscillator of the battery monitoring device.

[0005] However, configuring each oscillator of a battery monitoring device with a high-precision oscillator such as a crystal oscillator increases costs, which is an issue. The battery monitoring device of the present disclosure addresses such an issue, and aims to provide a battery monitoring device in a battery monitoring system with signal communication via a daisy chain connection with sufficient measurement accuracy without using a high-precision oscillator. [Means for solving the problem]

[0006] The present disclosure has been made to solve at least a part of the above-mentioned problems, and can be realized in the following forms.

[0007] According to one embodiment of the present disclosure, there is provided a battery monitoring system (100) for monitoring the states of a plurality of batteries. The battery monitoring system includes a battery monitoring ECU (10) and a plurality of battery monitoring devices (30), the battery monitoring ECU and the plurality of battery monitoring devices are connected in any one of a ring connection, a daisy chain connection, and a multi-drop connection, Furthermore, each of the plurality of battery monitoring devices (30) is connected such that one battery monitoring device is in a front-stage / rear-stage relationship with another battery monitoring device, The battery monitoring ECU includes a first clock generating unit (12) that generates a first clock signal, and a first clock signal that: The battery monitoring device includes at least one of information for identifying a battery to be monitored by the battery monitoring device and a correction instruction for causing the battery monitoring device to correct the frequency of the second clock signal. outputting a superimposed signal having the battery monitoring information superimposed thereon to at least one of the battery monitoring devices; Including the remaining charge of the battery a transmitter / receiver (16) that receives the monitoring result of the state of the battery, and each of the battery monitoring devices includes a receiver (42) that receives the superimposed signal from the previous stage, a second clock generator (50) that generates a second clock signal that serves as a reference for the operation of the battery monitoring device, and a controller (48) that extracts the clock of the superimposed signal from the previous stage as a reference clock signal and restores the battery monitoring information, When the battery monitoring information identifies the battery monitoring in the battery monitoring device, the battery monitoring is performed by an AC impedance method. The second clock signal No. a battery monitoring unit (54) for monitoring a state of the battery using a frequency difference between the frequency of the reference clock signal and the frequency of the second clock signal; a frequency monitoring unit (53) for monitoring the difference between the frequency of the reference clock signal and the frequency of the second clock signal; the battery monitoring information, the monitoring results for each stage up to the current stage, and difference information indicating the difference between the respective stages up to the current stage; is superimposed on the second clock signal of the current stage.and a transmitting section (44) that outputs the signal to a subsequent stage.

[0008] According to this embodiment of the battery monitoring system, the control unit of the battery monitoring ECU can obtain the error in frequency of the second clock signal of the battery monitoring device at each stage relative to the first clock signal, and can monitor the oscillation frequency information of all oscillators. Then, the control unit can determine how much the frequency of the second clock signal of each battery monitoring device at each stage should be corrected.

[0009] The present disclosure may be realized in various forms, for example, as a battery monitoring system, a battery monitoring method, or the like. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a battery monitoring system according to a first embodiment. [Diagram 2] 4 is a flowchart of a process executed by a control unit of a battery monitoring ECU. [Diagram 3] 4 is a flowchart showing an operation executed by a control unit of the battery monitoring device. [Figure 4] 4 is an explanatory diagram showing a first superimposed signal transmitted by a battery monitoring ECU and a second superimposed signal transmitted and received by a battery monitoring device; [Diagram 5] FIG. 11 is a schematic configuration diagram of a battery monitoring system according to a second embodiment. [Figure 6] FIG. 11 is a schematic configuration diagram of a battery monitoring system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First embodiment: Battery monitoring system 100 includes: As shown in FIG. 1, the battery monitoring system 100 includes a battery monitoring ECU 10 and a plurality of (m in this embodiment, m is an integer of 2 or more) battery monitoring devices 30. The xth stage (x is an integer from 1 to m) battery monitoring device 30 monitors the battery states of n (n is an integer of 1 or more) secondary batteries (hereinafter referred to as "batteries") included in the xth stage battery set CSx. Therefore, the battery monitoring system 100 monitors the battery states of a plurality of (m×n in this embodiment) batteries C11 to Cmn. Note that in this embodiment, the number of batteries monitored by the battery monitoring devices 30 in each stage is the same as n, but the number of batteries monitored by the battery monitoring devices 30 in each stage may be different.

[0012] The battery monitoring ECU 10 has two connection parts 18, 20, and each battery monitoring device 30 has two connection parts 34, 36. The battery monitoring ECU 10 and the multiple battery monitoring devices 30 are connected in a ring configuration. That is, one connection part 18 of the battery monitoring ECU 10 is connected to one connection part 34 of the first-stage battery monitoring device 30 by a transmission line 22. The other connection part 36 of the first-stage battery monitoring device 30 is connected to one connection part 34 of the second-stage battery monitoring device 30 by a transmission line 24. The other connection part 36 of the second-stage battery monitoring device 30 is connected to one connection part 34 of the third-stage battery monitoring device 30 by a transmission line 25. From here on, up to the battery monitoring device 30 of the final stage, the other connection part 36 of the battery monitoring device 30 of the previous stage is connected to one connection part 34 of the battery monitoring device 30 of the current stage by a transmission line. The other connection part 36 of the battery monitoring device 30 in the m-th stage, which is the final stage, is connected to the other connection part 20 of the battery monitoring ECU 10 by a transmission line 26. In this manner, the battery monitoring ECU 10 and the multiple battery monitoring devices 30 are connected to form a ring.

[0013] Although details will be described later, the battery monitoring ECU 10 operates based on a first clock signal generated by its own first clock generating unit 12, and the battery monitoring device 30 operates based on a second clock signal generated by its own second clock generating unit 50. When a control unit 48 of the battery monitoring device 30 receives an instruction to correct the second clock signal from the battery monitoring ECU 10, it causes the second clock generating unit 50 to correct the frequency of the second clock signal so that the frequency of the second clock signal is synchronized with or approaches the frequency of the first clock signal.

[0014] The configurations of the battery monitoring ECU 10 and the battery monitoring device 30 will be described below. The battery monitoring ECU 10 includes a first clock generating unit 12, a higher-level control unit 14, a transmission / reception unit 16, and the above-mentioned connection units 18 and 20. The first clock generating unit 12 generates a first clock signal that is the basis for the operation of the battery monitoring ECU 10. The first clock generating unit 12 uses a crystal oscillator to generate the first clock signal, which is a highly accurate clock signal. The first clock generating unit 12 may use an oscillator other than a crystal oscillator, for example, a silicon MEMS oscillator. The first clock generating unit 12 may also receive a signal generated by a GNSS disciplined frequency generator from a GNSS satellite to generate the first clock signal.

[0015] The upper control unit 14 generates a first superimposed signal by superimposing the battery monitoring information on the first clock signal, and sends the first superimposed signal to the transmission / reception unit 16. The battery monitoring information includes information for identifying the battery to be monitored by the battery monitoring device 30 and a correction instruction indicating whether to cause the battery monitoring device 30 to correct the frequency of the second clock signal. The information for identifying the battery to be monitored in the battery monitoring information indicates which battery should be monitored. The battery to be monitored may be a specific battery of a specific set, a specific number of batteries of a specific set, all batteries of a specific set, or all batteries of all sets. The correction instruction includes information for identifying which battery monitoring device 30 is to have its second clock signal corrected and the battery monitoring device 30 to be corrected. In this embodiment, the correction instruction includes information indicating how much the frequency of the second clock signal is to be corrected, that is, the correction amount of the frequency of the second clock signal in the battery monitoring device 30 to be corrected.

[0016] The battery monitoring information is superimposed on the first clock signal by, for example, phase encoding using the Manchester code. The battery monitoring information may be superimposed by a method other than phase encoding using the Manchester code, for example, phase shift keying.

[0017] The transmitter / receiver 16 outputs an instruction related to battery monitoring to at least one of the battery monitoring devices 30, and receives the result of the instruction from at least one of the battery monitoring devices 30. The transmitter / receiver 16 generates a differential signal from the first superimposed signal and transmits it to the transmission path 22 via the connection unit 18. A differential signal is a signal in which one signal is divided into two signals of opposite phase to each other. The transmission paths 22, 26 connecting the battery monitoring ECU 10 and the battery monitoring device 30, and the transmission paths 24, 25, . . . connecting the battery monitoring device 30 and the battery monitoring device each have two signal lines. The transmitter / receiver 16 transmits an original signal to one of the two signal lines of the transmission path 22, and transmits a signal of opposite phase in which H and L are inverted to the signal of the one signal line to the other signal line. The connection unit 18 has a capacitor, and connects the transmitter / receiver 16 to the transmission path 22 via the capacitor. Therefore, the connection unit 18 does not transmit the DC component of the differential signal, but transmits only the AC component.

[0018] The transceiver 16 also receives a differential signal of a second superimposed signal obtained by superimposing battery monitoring information, battery monitoring results of the battery monitoring devices 30 up to the previous stage, and difference information of the second clock signal of the battery monitoring devices 30 up to the previous stage from the final stage battery monitoring device 30 via the transmission path 26 and the connection unit 20, and restores the second superimposed signal. The battery monitoring result is a result of the battery monitoring process performed by each battery monitoring device 30 based on the battery monitoring information received from the battery monitoring ECU 10, and includes information identifying the battery monitored up to the previous stage and measurement results of the state of the battery monitored by the battery monitoring devices 30 up to the previous stage. The difference information of the second clock signal of the battery monitoring device 30 is information indicating the difference in frequency between the second clock signal of the battery monitoring device 30 and the clock signal of the device up to the previous stage. The difference information of the second clock signal will be described later. The connection unit 20 has a capacitor, similar to the connection unit 18, and connects the transmission path 26 and the transceiver 16 via the capacitor. The connecting portion 20 does not transmit the DC component of the differential signal, but transmits only the AC component. The connecting portions 18 and 20 may be formed of a transformer instead of a capacitor.

[0019] The battery monitoring device 30 includes a battery monitoring IC 40, a filter 60, and the above-mentioned connections 34, 36. The battery monitoring IC 40 includes a receiver 42, a transmitter 44, a control unit 48, a second clock generator 50, a frequency monitor 53, and a battery monitor 54. The receiver 42 is connected to the connection unit 34, and the transmitter 44 is connected to the connection unit 36. The control unit 48 is connected to the receiver 42 and the transmitter 44. The control unit 48 is connected to the second clock generator 50, the frequency monitor 53, and the battery monitor 54. The battery monitor 54 is connected to the battery via the filter 60.

[0020] The receiving unit 42 of the first-stage battery monitoring device 30 is connected to the transmitting / receiving unit 16 of the battery monitoring ECU 10 via the connection unit 34, the transmission path 22, and the connection unit 18. The receiving units 42 of the second-stage to m-th-stage battery monitoring devices 30 are each connected to the transmitting unit 44 of the previous-stage battery monitoring device 30 via the connection unit 34, the transmission paths 24, 25, ..., and the connection unit 36. The transmitting unit 44 of the m-th-stage battery monitoring device 30 is connected to the transmitting / receiving unit 16 of the battery monitoring ECU 10 via the connection unit 36, the transmission path 26, and the connection unit 20.

[0021] The receiver 42 receives the differential signal from the device in the previous stage and restores the superimposed signal from the differential signal. Here, the device in the previous stage is the battery monitoring ECU 10 if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the first stage, and is the battery monitoring device 30 if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the second to mth stages. Here, the superimposed signal is a first superimposed signal if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the first stage, and is a second superimposed signal generated by the battery monitoring device 30 in the previous stage if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the second to mth stages.

[0022] The control unit 48 extracts the clock of the superimposed signal received by the receiving unit 42 as a reference clock signal, and restores and decodes from the superimposed signal the battery monitoring information, the battery monitoring results up to the previous stage, and the difference information between the second clock signals of the battery monitoring devices 30 up to the previous stage. If the control unit 48 is the control unit 48 of the first-stage battery monitoring device 30, the superimposed signal is the first superimposed signal generated by the upper control unit 14 of the battery monitoring ECU 10, and the battery monitoring results up to the previous stage and the difference information between the second clock signals of the battery monitoring devices 30 up to the previous stage are not included in the superimposed signal.

[0023] The reference clock signal is a clock signal restored from the received superimposed signal before superimposition. Therefore, in the first stage battery monitoring device 30, the frequency of the reference clock signal is the same as the frequency of the first clock signal, and in the second to mth stages battery monitoring devices 30, the frequency of the reference clock signal is the same as the frequency of the second clock signal of the battery monitoring device 30 of the previous stage.

[0024] The control unit 48 superimposes the battery monitoring information, the battery monitoring results up to the current stage, and difference information of the second clock signal of the battery monitoring device 30 up to the current stage on the second clock signal to generate a second superimposed signal.

[0025] The second clock generating unit 50 generates a second clock signal that is a reference for the operation of its own battery monitoring device 30. The second clock generating unit 50 is configured using an LC oscillator that is simpler than the crystal oscillator used in the first clock generating unit 12. Therefore, the second clock signal is a clock signal with lower accuracy compared to the first clock signal. Since the second clock generating unit 50 uses an LC oscillator, the oscillation frequency can be easily changed and corrected by changing the capacitance of the capacitor that constitutes the LC oscillator or the inductance that constitutes the inductor according to a correction instruction from the control unit 48.

[0026] The frequency monitor 53 monitors the second clock signal generated by the second clock generator 50 and the reference clock signal, and detects the difference between the frequency of the second clock signal and the frequency of the reference clock signal. The controller 48 obtains this difference as difference information of the second clock signal.

[0027] The battery monitoring unit 54 detects the battery state by an AC impedance method using the second clock signal. Note that the control unit 48 may cause the battery monitoring unit 54 to constantly monitor the battery state, and when the battery monitoring information indicates a battery being monitored, obtain the measurement result of the state of the battery detected by the battery monitoring unit 54.

[0028] The transmitter 44 generates a differential signal from the second superimposed signal and transmits it to a downstream device. Here, the downstream device is the battery monitoring device 30 if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the 1st to (m-1)th stages, and is the battery monitoring ECU 10 if the control unit 48 is the control unit 48 of the battery monitoring device 30 in the mth stage.

[0029] Operation of the battery monitoring system 100: 2 is a process flow chart executed by the upper control unit 14 of the battery monitoring ECU 10. In step S10, the upper control unit 14 of the battery monitoring ECU 10 transmits battery monitoring information to the first-stage battery monitoring device 30. Specifically, the upper control unit 14 of the battery monitoring ECU 10 generates a first superimposed signal by superimposing the battery monitoring information on a first clock signal. The upper control unit 14 causes the transmitting / receiving unit 16 to generate a differential signal from the first superimposed signal and transmit the differential signal to the first-stage battery monitoring device 30. This battery monitoring information includes correction instruction information indicating whether or not the frequency of the second clock signal of the battery monitoring device 30 should be corrected. Note that the instruction to acquire the initial battery state does not include a correction instruction to correct the frequency of the second clock signal of the battery monitoring device 30.

[0030] In step S20, the upper control unit 14 of the battery monitoring ECU 10 receives, from the m-th battery monitoring device 30 which is the final stage, the battery monitoring result in response to the instruction to monitor the battery state and difference information of the second clock signal of the battery monitoring device 30, and this result is superimposed on the second superimposed signal. If the determination result in step S20 is true (T) that the upper control unit 14 has received the second superimposed signal, the upper control unit 14 transitions the process to step S30. On the other hand, if the determination result in step S20 is false (F) that the second superimposed signal has not been received, the upper control unit 14 repeats step S20 until it becomes true (T) that the second superimposed signal has been received.

[0031] In step S30, the upper control unit 14 recovers from the second superimposed signal the monitoring results of the battery status in the battery monitoring device 30 of each stage and differential information which is the deviation of the frequency of the second clock signal in the battery monitoring device 30 of each stage from the frequency of the reference clock signal.

[0032] In step S40, the upper control unit 14 calculates and obtains the frequency of the second clock signal in the battery monitoring device 30 of each stage using the frequency of the first clock signal, the frequency of the reference clock signal and the difference information of the frequency of the second clock signal in the battery monitoring device 30 of each stage.

[0033] Steps S50 to S100 are a loop, and the upper control unit 14 performs processing for the battery monitoring device 30 of each stage. In step S60, the upper control unit 14 judges the relationship between the difference Δf between the frequency of the first clock signal and the frequency of the second clock signal and the magnitude of two thresholds, the first threshold TH1 and the second threshold TH2. The second threshold TH2 is greater than the first threshold TH1. If the absolute value |Δf| of the frequency difference Δf is equal to or less than the first threshold TH1, the upper control unit 14 shifts the processing to step S70. If the absolute value |Δf| of the frequency difference Δf is greater than the first threshold TH1 and equal to or less than the second threshold TH2, the upper control unit 14 shifts the processing to step S80. If the absolute value |Δf| of the frequency difference Δf is greater than the second threshold TH2, the upper control unit 14 shifts the processing to step S90.

[0034] In step S70, the upper control unit 14 acquires the monitoring result of the battery state by the battery monitoring device 30, which is superimposed on the second superimposed signal, as the monitoring result of the battery state as it is, and then proceeds to step S100.

[0035] In step S80, the upper control unit 14 corrects the monitoring result of the battery state by the battery monitoring device 30, which is superimposed on the second superimposed signal, using the difference between the frequency of the first clock signal and the frequency of the second clock signal, and acquires it as the monitoring result of the battery state. Then, the process proceeds to step S100.

[0036] In step S90, the upper level control unit 14 determines that the frequency of the second clock signal should be corrected, and then the process proceeds to step S100.

[0037] In step S110, the upper control unit 14 judges whether or not to monitor the battery in the next cycle. When the absolute value |Δf| of the frequency difference Δf is greater than the second threshold value TH2 for at least one of the battery monitoring devices 30, the upper control unit 14 may judge to monitor the battery in the next cycle. If the judgment in step S110 is true (T) that the next cycle is to be monitored, the upper control unit 14 shifts the process to step S10 and repeats the above-mentioned process. Note that in step S10 after the next cycle when the process returns from step S110 to step S10, the battery monitoring information includes a correction instruction to correct the frequency of the second clock signal of the battery monitoring device 30. Therefore, the battery monitoring device 30 that has received this correction instruction corrects the frequency of the second clock signal. If the judgment in step S110 is false (F) that the next cycle is not to be monitored, the upper control unit 14 ends the process.

[0038] 3 is an operational flowchart executed by the control unit 48 of the battery monitoring device 30. In step S200, the control unit 48 receives a superimposed signal from the device in the preceding stage through the receiving unit 42. Here, the device in the preceding stage is the battery monitoring ECU 10 when the battery monitoring device 30 is the first stage battery monitoring device, and is the battery monitoring device 30 when the battery monitoring device 30 is the second to mth stage battery monitoring device. In addition, the superimposed signal is a first superimposed signal when the battery monitoring device 30 is the first stage battery monitoring device, and is a second superimposed signal when the battery monitoring device 30 is the second to mth stage battery monitoring device.

[0039] In step S210, the control unit 48 restores and decodes the superimposed signal to generate a reference clock signal. In the first-stage battery monitoring device 30, the superimposed signal is a first superimposed signal. Therefore, the control unit 48 generates a reference clock signal with the same frequency as the frequency of the first clock signal, and acquires battery monitoring information. In the second-stage to m-th-stage battery monitoring devices 30, the superimposed signal is a second superimposed signal. Therefore, the control unit 48 generates a reference clock signal with the same frequency as the frequency of the second clock signal of the previous stage, and acquires battery monitoring information, monitoring results of the battery status in each stage up to the previous stage (also referred to as "battery monitoring results"), and difference information indicating the deviation in frequency of the second clock signal from the reference clock signal in each stage up to the previous stage.

[0040] In step S220, the control unit 48 determines whether or not the battery monitoring information includes a correction instruction to correct the frequency of the second clock signal. If the determination in step S220 is true (T), that is, the battery monitoring information includes a correction instruction to correct the frequency of the second clock signal, the control unit 48 proceeds to step S230. On the other hand, if the determination in step S220 is false (F), that is, the battery monitoring information does not include a correction instruction to correct the frequency of the second clock signal, the control unit 48 proceeds to step S240.

[0041] In step S230, the control unit 48 instructs the second clock generating unit 50 to correct the frequency of the second clock signal. Upon receiving the correction instruction, the second clock generating unit 50 changes and corrects the oscillation frequency by changing the capacitance of the capacitor constituting the LC oscillator or the inductance constituting the inductor, as described above.

[0042] In step S240, the control unit 48 obtains from the frequency monitoring unit 53 the difference between the frequency of the reference clock signal and the frequency of the second clock signal generated by the second clock generating unit 50.

[0043] In step S250, the control unit 48 acquires from the battery monitoring unit 54 the state of the battery being monitored, which is detected by the battery monitoring unit 54 using the second clock signal.

[0044] In step S260, the control unit 48 superimposes the battery monitoring information, the battery monitoring results for each stage up to the current stage, and difference information indicating the frequency deviation between the reference clock signal and the second clock signal for each stage up to the current stage onto the second clock signal to generate a second superimposed signal.

[0045] In step S270, the control unit 48 causes the transmission unit 44 to generate a differential signal from the second superimposed signal and transmit the signal to a downstream device. As described above, the downstream device is the battery monitoring ECU 10 when the control unit 48 is a battery monitoring device 30 in the m-th stage, which is the final stage, and is the battery monitoring device 30 when the control unit 48 is a battery monitoring device 30 in a stage other than the m-th stage.

[0046] 4 is an explanatory diagram showing a first superimposed signal transmitted by the battery monitoring ECU 10 and a second superimposed signal transmitted and received by the battery monitoring device 30. The battery monitoring ECU 10 transmits a first superimposed signal of frequency f0. The receiver 42 of the battery monitoring device 30 in the first stage receives the first superimposed signal of frequency f0, and the transmitter 44 of the battery monitoring device 30 in the first stage transmits a second superimposed signal of frequency f1. The receiver 42 of the battery monitoring device 30 in the second stage receives the second superimposed signal of frequency f1, and the transmitter 44 of the battery monitoring device 30 in the second stage transmits a second superimposed signal of frequency f2. Similarly, the receiver 42 of the battery monitoring device 30 in the xth stage receives the second superimposed signal of f(x-1), and the transmitter 44 of the battery monitoring device 30 in the xth stage transmits a second superimposed signal of frequency fx.

[0047] In the first stage battery monitoring device 30, the frequency f1-f0 is the difference Δf1, which is the relative deviation between the frequency of the reference clock signal (first clock signal) and the frequency of the second clock signal in the first stage. In the second stage battery monitoring device 30, the frequency f2-f1 is the difference Δf2, which is the relative deviation between the frequency of the reference clock signal (second clock signal) and the frequency of the second clock signal in the second stage. Similarly, in the xth stage battery monitoring device 30, the frequency fx-f(x-1) is the difference Δfx, which is the relative deviation between the frequency of the reference clock signal (second clock signal) and the frequency of the second clock signal in the xth stage. In the xth stage battery monitoring device 30, the control unit 48 sequentially adds the differences Δf1 to Δfx up to the xth stage when generating the second superimposed signal. That is, the frequency differences Δf1 to Δfm in the battery monitoring devices 30 in each stage are added to the second superimposed signal.

[0048] The battery monitoring ECU 10 calculates the frequency of the second clock signal in order from the first stage battery monitoring device 30 using the frequency information of the first clock signal and the frequency differences Δf1 to Δfm in the battery monitoring devices 30 of each stage. That is, the frequency f1 of the second clock of the first stage battery monitoring device 30 is f0+Δf1, and the frequency f2 of the second clock of the second stage battery monitoring device 30 is f1+Δf2=f0+Δf1+Δf2. Similarly, the upper control unit 14 can calculate the frequencies f3 to fm of the second clock of the battery monitoring devices 30 of the third stage to the mth stage. The upper control unit 14 can obtain the absolute frequency error of the second clock signal of each stage with respect to the frequency f0 of the first clock signal by comparing the frequency f0 of the first clock signal with the frequencies f1 to fm of the second clock signal of the battery monitoring devices 30 of each stage. The host control unit 14 can then determine which stage of the battery monitoring device 30 the frequency of which should be corrected and by how much.

[0049] As described above, according to this embodiment, the control unit 48 of the battery monitoring device 30 outputs the monitoring result of the frequency of the second clock signal to the subsequent stage. As a result, the host control unit 14 of the battery monitoring ECU 10 can calculate the frequency of the second clock signal at each stage using the monitoring result of the frequency of the second clock signal at each stage and determine which battery monitoring device 30's second clock signal should be corrected.

[0050] In this embodiment, the upper control unit 14 of the battery monitoring ECU 10 transmits a correction instruction to the battery monitoring devices 30, but in the battery monitoring devices 30 of each stage, the control unit 48 extracts the difference from the first stage to the previous stage contained in the superimposed signal from the previous stage, and taking these into consideration, determines the frequency difference between the frequency of the first clock signal received by the first stage from the battery monitoring ECU and the frequency of the second clock signal of the current stage, and if this frequency difference is greater than a predetermined threshold, the control unit 48 of the current stage may cause the second clock generating unit 50 to correct the frequency of the second clock signal in accordance with the frequency deviation. This can reduce the number of battery monitoring devices 30 whose second clock signals need to be corrected in the next cycle.

[0051] According to this embodiment, the upper control unit 14 can use the difference information in each stage of the battery monitoring device 30 to calculate and obtain the absolute frequency deviation of the second clock signal from the frequency of the first clock signal.

[0052] According to this embodiment, the upper control unit 14 can obtain the absolute frequency deviation of the second clock signal relative to the first clock signal together with the state of the battery.

[0053] According to this embodiment, when the difference between the frequency of the first clock signal and the frequency of the second clock signal in the battery monitoring device 30 is greater than a first threshold value TH1 and is equal to or less than a second threshold value TH2, the upper control unit 14 can correct and obtain the battery state using the difference between the frequencies of the first and second clock signals.

[0054] According to this embodiment, when the frequency monitoring unit 53 of the current stage determines that the relative deviation of the frequency of the second clock signal with respect to the frequency of the reference clock signal extracted from the superimposed signal received from the battery monitoring device 30 of the previous stage is greater than a predetermined threshold value, the control unit 48 of the current stage can cause the second clock generating unit to correct the frequency of the second clock signal in accordance with the frequency deviation.

[0055] Second embodiment: FIG. 5 is a schematic diagram of a battery monitoring system 101 of the second embodiment. In the battery monitoring system 101 of the second embodiment, the battery monitoring ECU 11 does not include the connection unit 20, and the transmission / reception unit 16 is connected to the transmission path 22 via the connection unit 18. The battery monitoring device 32 is different from the battery monitoring system 100 of the first embodiment in that it includes a transmission / reception unit 43 instead of the reception unit 42 and the transmission unit 44, and the battery monitoring ECU 10 and the multiple battery monitoring devices 32 are daisy-chained. The battery monitoring device 32 includes two connection units 34 and 36, and the connection unit 36 ​​of the battery monitoring device 32 in the last stage, the m-th stage, is connected to the termination device 28. Depending on the configuration of the transmission / reception unit 43, the termination device 28 may not be connected to the connection unit 36. In the first embodiment, the connection unit 34 was used as the input unit and the connection unit 36 ​​was used as the output unit, but in the third embodiment, the connection unit 34 functions as the input unit and the connection unit 36 ​​functions as the output unit, but it is possible to switch so that the connection unit 36 ​​also functions as the input unit and the connection unit 34 functions as the output unit. The second superimposed signal from the m-th stage, which is the last stage, is transmitted in the reverse direction from the battery monitoring device 32 in the m-th stage to the battery monitoring device 32 in the first stage.

[0056] In the second embodiment, similarly to the first embodiment, the host control unit 14 can obtain the error in the frequency of the second clock signal of each stage by comparing the frequency f0 of the first clock signal with the frequencies f1 to fm of the second clock signals in the battery monitoring devices 30 of each stage. Then, the host control unit 14 can determine how much the frequency of the battery monitoring device 30 of each stage should be corrected.

[0057] Third embodiment: 6 is a schematic configuration diagram of a battery monitoring system 102 of the third embodiment. In the battery monitoring system 102 of the fourth embodiment, a plurality of battery monitoring devices 33 are multi-drop connected to a battery monitoring ECU 11. The transmitter / receiver 16 of the battery monitoring ECU 11 does not have a connection unit 20, and is connected to a transmission path 27 via a connection unit 18. Each battery monitoring device 33 does not have a connection unit 36, and a receiver 42 and a transmitter 44 are connected to one connection unit 34, and the connection unit 34 is connected to the transmission path 27.

[0058] In the battery monitoring system 102 of the third embodiment, a signal from the battery monitoring ECU 11 is transmitted to the receiving unit 42 of the first-stage battery monitoring ECU 11 via the connection unit 18 and the transmission path 27. The signal output from the first-stage battery monitoring ECU 11 is transmitted from the transmitting unit 44 to the receiving unit 42 of the second-stage battery monitoring ECU 11, which is the next stage, via the connecting unit 34 and the transmission path 27. Similarly, the signal output from the x-stage battery monitoring ECU 11 is transmitted from the transmitting unit 44 to the receiving unit 42 of the (x+1)-th stage battery monitoring ECU 11, which is the next stage, via the connecting unit 34 and the transmission path 27. The signal output from the m-th stage battery monitoring ECU 11, which is the final stage, is transmitted from the transmitting unit 44 to the transmitting / receiving unit 16 of the battery monitoring ECU 11 via the connecting unit 34 and the transmission path 27. In this manner, each battery monitoring device 30 sequentially transmits the superimposed signal using the same transmission path 27. Regarding transmission, each battery monitoring device 30 has the right to use the transmission path 27 in sequence using a token, and transmits a superimposed signal to the subsequent stage.

[0059] In the third embodiment, the operation is the same as in the first embodiment, and similarly to the first embodiment, the host control unit 14 can obtain the absolute frequency error of the second clock signal in each stage of the battery monitoring device 30 relative to the first clock signal by comparing the frequency f0 of the first clock signal with the frequencies f1 to fm of the second clock signals in the battery monitoring device 30 in each stage. Then, the host control unit 14 can determine how much the frequency of the battery monitoring device 30 in each stage should be corrected.

[0060] As can be seen from the first to fourth embodiments, the battery monitoring ECU and multiple battery monitoring devices can be connected in various configurations, such as a ring connection, a daisy chain connection, or a multi-drop connection.

[0061] The present disclosure is not limited to the above-mentioned embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention column can be appropriately replaced or combined in order to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0062] Reference Signs List 10, 11... battery monitoring ECU, 12... first clock generation unit, 14... upper control unit, 16... transmitter / receiver unit, 18, 20... connection unit, 22, 24, 25, 26, 27... transmission path, 28... termination device, 30, 32, 33... battery monitoring device, 34, 36... connection unit, 40... battery monitoring IC, 42... receiver unit, 43... transmitter / receiver unit, 44... transmitter unit, 48... control unit, 50... second clock generation unit, 53... frequency monitoring unit, 54... battery monitoring unit, 60... filter, 100, 101, 102... battery monitoring system

Claims

1. A battery monitoring system (100) for monitoring the state of a plurality of batteries, comprising: A battery monitoring ECU (10); A plurality of battery monitoring devices (30), the battery monitoring ECU and the plurality of battery monitoring devices are connected in any one of a ring connection, a daisy chain connection, and a multi-drop connection, and each of the plurality of battery monitoring devices (30) is connected such that one battery monitoring device is in a preceding-stage / rear-stage relationship with another battery monitoring device, The battery monitoring ECU A first clock generating unit (12) that generates a first clock signal; a transceiver (16) that outputs to at least one of the battery monitoring devices a superimposed signal obtained by superimposing battery monitoring information, the superimposed signal including at least one of information for identifying a battery to be monitored by the battery monitoring device and a correction instruction to the battery monitoring device for correcting the frequency of the second clock signal, on the first clock signal, and receives a monitoring result of the state of the battery including a remaining capacity of the battery, Each of the battery monitoring devices is A receiving unit (42) that receives the superimposed signal from the previous stage; A second clock generating unit (50) that generates a second clock signal that is a reference for its own operation; a control unit (48) that extracts a clock of the superimposed signal from the previous stage as a reference clock signal and restores the battery monitoring information; a battery monitoring unit (54) that monitors a state of the battery using the second clock signal by an AC impedance method when the battery monitoring information specifies that the battery is being monitored by the battery monitoring device; a frequency monitoring unit (53) that monitors a difference between a frequency of the reference clock signal and a frequency of the second clock signal; a transmission unit (44) that superimposes the battery monitoring information, the monitoring results in each stage up to the current stage, and difference information indicating the difference in each stage up to the current stage on the second clock signal of the current stage and outputs the superimposed information to a subsequent stage; A battery monitoring system comprising:

2. 2. The battery monitoring system according to claim 1, The battery monitoring system includes an upper control unit (14) in which the battery monitoring ECU calculates the absolute frequency deviation of the second clock signal of each stage relative to the frequency of the first clock signal by starting from the frequency of the second clock signal from the final stage and sequentially applying the difference information at each stage of the battery monitoring device to the frequency, working backwards from the final stage.

3. 3. The battery monitoring system according to claim 2, The upper control unit obtains an absolute frequency deviation of the second clock signal relative to the first clock signal together with a state of the battery.

4. The battery monitoring system according to claim 2 or 3, A battery monitoring system in which, when a difference between the frequency of the first clock signal and the frequency of the second clock signal in the battery monitoring device is greater than a first threshold (TH1) and is equal to or less than a second threshold (TH2), the upper control unit uses the difference in frequency between the first clock signal and the second clock signal and corrects and acquires the state of the battery, taking into account the difference in AC frequency in the AC impedance method.

5. A battery monitoring system according to any one of claims 1 to 4, A battery monitoring system in which, when the frequency monitoring unit of the current stage determines that the relative deviation of the frequency of the second clock signal from the frequency of the reference clock signal extracted from the superimposed signal received from the battery monitoring device of the previous stage is greater than a predetermined threshold, the control unit of the current stage causes the second clock generating unit to correct the frequency of the second clock signal so as to approach the frequency of the first clock signal in accordance with the frequency deviation.

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