Device and energy storage system

Abstract

A device includes one master device 65 and a plurality of slave devices 70. The one master device 65 and the plurality of slave devices 70 are daisy-chained via a communication line L. After assigning consecutive device addresses to all of the devices, the master device 65 performs communication via the communication line L to perform a response check with each of the plurality of slave devices 70. The master device 65 detects the number Q of the slave devices 70 connected in series on the basis of the device addresses of the slave devices 70 with which the response check has been successful and compares the detected number with a setting value Q.

Description

Devices, energy storage systems

[0001] The present invention relates to daisy-chained devices.

[0002] In order to achieve efficient energy management, the introduction of energy storage systems is being promoted. When the demand for electricity is lower than the supply, the energy storage system charges a storage battery with surplus electricity, and when the demand for electricity exceeds the supply, the storage battery is discharged to make up for the power shortage. Patent Document 1 discloses a technology related to the energy storage system.

[0003] JP 2023-65595 A

[0004] A typical energy storage bank is configured by connecting multiple energy storage modules (units of multiple energy storage cells) in series, with a module monitoring device monitoring the status of the energy storage modules and a bank monitoring device monitoring the entire energy storage bank.

[0005] In a communication format in which a bank monitoring device (master device) and a module monitoring device (slave device) are daisy-chained, there was no established technology to detect connection or communication abnormalities in the module monitoring device. This issue was not limited to monitoring devices for power storage banks, but was present in all daisy-chained devices.

[0006] An object of the present invention is to detect connection abnormalities or communication abnormalities in slave devices by detecting the serial number of slave devices and comparing it with a set value in a communication configuration in which a master device and slave devices are daisy-chain connected.

[0007] A device apparatus according to one embodiment of the present invention includes one master device and a plurality of slave devices, which are daisy-chained together by a communication line.

[0008] The master device assigns consecutive device addresses to all devices, and then communicates via the communication line to confirm the response of each of the slave devices. The master device detects the serial number of the slave devices based on the device addresses of the slave devices whose responses have been successfully confirmed, and compares the detected serial number with a set value.

[0009] In a communication configuration in which a master device and slave devices are daisy-chained, this technology detects the serial number of the slave device and compares it with a set value, making it possible to detect connection or communication abnormalities in the slave device.

[0010] Block diagram of the energy storage system Block diagram of the battery panel Perspective view of the storage module Diagram showing the communication method between the bank monitoring device and the module monitoring device Diagram showing the IC startup sequence Diagram showing the device addresses of each device Abnormality determination sequence Diagram showing the device addresses of each device Diagram showing the device addresses of each device

[0011] (Outline of this embodiment) (1) A device apparatus according to one embodiment of the present invention includes one master device and multiple slave devices, and the one master device and the multiple slave devices are daisy-chain connected by communication lines.

[0012] The master device assigns consecutive device addresses to all devices, and then confirms the response of each of the slave devices through communication via the communication line. The master device detects the serial number of the slave device based on the device address of the slave device whose response has been confirmed successfully, and compares the detected serial number with a set value. The master device is a device that controls or manages the slave devices. In the device apparatus described in (1), any configuration other than the above is optional and may be used.

[0013] The following explains the operation and effect of the device apparatus described in (1). Since the device addresses assigned to all devices are consecutive, by referencing the device addresses of the slave devices whose responses have been successfully confirmed, it is possible to determine from which numbers the responses have been confirmed, and from which numbers onwards or before which the responses have not been confirmed. Therefore, it is possible to find the serial number of the slave devices from the device addresses of the slave devices whose responses have been successfully confirmed.

[0014] This method allows the master device to automatically detect the serial number of slave devices through software processing. Furthermore, by comparing the serial number with a set value, the comparison result can detect the presence or absence of connection abnormalities or communication circuit failures of the slave devices. For example, by detecting the serial number of slave devices and comparing it with the set value when the device is started, the comparison result can detect the presence or absence of connection abnormalities or communication abnormalities (circuit failures), thereby preventing the device from reaching an unsafe event.

[0015] (2) In the device apparatus described in (1), the master device may set a total number of all devices connected in a daisy chain based on the maximum serial number of the slave devices. The master device may assign device addresses, which are obtained by subtracting one from the total number of devices, to all devices connected in the daisy chain in order from the master device to the top device of the slave devices. The master device may perform response confirmation on the slave devices connected in the daisy chain in ascending order of device addresses. The master device may calculate the serial number of the slave devices by subtracting the device address of the slave device whose response was successfully confirmed first from the total number of devices. In the device apparatus described in (2), any configuration other than the above is optional and may be used.

[0016] The device apparatus described in (2) can calculate the serial number of slave devices by subtracting the device address of the slave device that first succeeded in confirming the response from the total number of devices.

[0017] (3) In the device apparatus according to (1) or (2), the total number of devices may be a value obtained by adding 2 to the maximum number of serial connections of the slave devices. In the device apparatus according to (3), any configuration other than the above is optional and may be any configuration.

[0018] The device apparatus described in (3) can detect that the number of slave devices connected is greater than the set value. For example, if the set value of the number of serial slave devices is 3, it can detect that four or more slave devices are connected.

[0019] (4) The device according to any one of (1) to (3) may be used for monitoring a power storage bank. The power storage bank may include a plurality of power storage modules. The slave device may be a monitoring device for the power storage modules. The master device may be a monitoring device for the power storage bank. This configuration can contribute to improving the reliability of the power storage bank monitoring system by detecting connection abnormalities.

[0020] (5) An energy storage system includes a PCS panel that houses a power conversion unit and a battery panel that houses a power storage bank connected to the power conversion unit via a power line. The power storage bank includes a plurality of power storage modules connected in series, a module monitoring device that monitors the power storage modules, and a bank monitoring device. The bank monitoring device and the plurality of module monitoring devices are daisy-chained via a communication line, and the bank monitoring device assigns consecutive device addresses to all monitoring devices and then confirms responses from each of the plurality of module monitoring devices via the communication line. The bank monitoring device detects the number of series of the module monitoring devices based on the device addresses of the module monitoring devices that successfully confirmed the responses and compares the detected number of series with a set value. In the energy storage system described in (5), any configuration other than the above is optional and may be used.

[0021] The number of series of energy storage modules can vary from project to project. If the number of series differs from the actual number due to incorrect or defective harness connections or communication abnormalities (circuit failures) during the construction (assembly) of the energy storage system and cannot be detected, it could lead to an unsafe event at the energy storage bank. By applying this technology, it is possible to detect the number of series of the module monitoring device. By comparing the number of series with the installed value, it is possible to detect the connection status (incorrect harness connections, defective harnesses, etc.) and communication abnormalities (circuit failures) of the module monitoring device. This makes it possible to prevent the energy storage bank from reaching an unsafe event.

[0022] (6) In the energy storage system described in (5), the bank monitoring device may detect the number of series of the module monitoring devices and compare it with a set value when the energy storage system is initially started. In the energy storage system described in (6), any configuration other than the above is optional and may be any configuration.

[0023] Energy storage systems require the assembly of complex and extensive wiring during on-site construction. In particular, when a storage bank is composed of multiple energy storage modules and a module monitoring device is installed for each energy storage module, the numerous wiring connections make harness connection errors and harness defects more likely. When such errors or defects occur, it takes time to identify the cause, delaying the construction of the energy storage system and preventing successful initial startup, directly leading to operational delays. Using this technology, during initial startup of the energy storage system, the number of series connections in the module monitoring device is detected and compared with a set value. From the comparison results, the module monitoring device's connection status (e.g., harness connection errors, harness defects, etc.) and communication abnormalities (circuit failures) can be determined. This allows for smooth initial startup of the energy storage system, contributing to early operation.

[0024] <First Embodiment> 1. Description of Energy Storage System 10 Fig. 1 is a block diagram of an energy storage system 10. The energy storage system 10 is a system that is connected to a power grid 1 and adjusts the supply and demand of power. The power grid 1 may be that of a power utility company, or may be an independent power grid that is based on the stand-alone operation output of a large-scale power conditioner.

[0025] The energy storage system 10 includes a battery panel 20 that stores energy, a PCS panel 30, and a remote monitoring panel 50. PCS is an abbreviation for Power Conditioning System.

[0026] The PCS panel 30 includes power conversion units 40A to 40C, a control unit 45, and a housing 31 that houses them. The power conversion units 40A to 40C are bidirectional power converters capable of reverse conversion (DC to AC) and forward conversion (AC to DC). The power conversion units 40A to 40C are connected to the power grid 1 via an interconnection switch 43.

[0027] The inverse conversion operation (DC → AC) of the power conversion units 40A to 40C allows the battery panel 20 to be discharged and AC power to be supplied to the power grid 1. In addition, the forward conversion operation (AC → DC) of the power conversion units 40A to 40C allows the battery panel 20 to be charged with AC power from the power grid 1.

[0028] In this embodiment, the capacity of the PCS board 30 is ensured by providing a plurality of three power conversion units 40A to 40C in parallel.

[0029] The control unit 45 includes, for example, a CPU (Central Processing Unit) and a memory for storing various data. The control unit 45 controls the power conversion units 40A to 40C in response to commands from a higher-level system such as an EMS (Energy Management System) and adjusts the supply and demand of power.

[0030] Specifically, when the demand for electricity is lower than the supply, the excess electricity is used to charge the battery panel 20 of the energy storage system 10, and when the demand for electricity exceeds the supply, the power shortage is made up by discharging the battery panel 20 of the energy storage system 10.

[0031] By exchanging power with the power grid 1 and adjusting supply and demand, it is possible to improve energy utilization efficiency and contribute to energy conservation.

[0032] The remote monitoring panel 50 is equipped with a communication board 55 for wireless communication with the remote monitoring device 100. The remote monitoring device 100 remotely monitors the state (SOC and temperature) of the battery panel 20 by communication via the remote monitoring panel 50. The remote monitoring panel 50 also has a communication function with a higher-level system, and commands from the higher-level system are notified to the control unit 45 of the PCS panel 30 via the remote monitoring panel 50.

[0033] 2 is a block diagram of the battery panel 20. The battery panel 20 is composed of one or more power storage banks 21, a thermistor 22 that detects the temperature of the battery panel 20, a panel air conditioner 23 that controls the temperature of the battery panel 20, a fire detection system 24, a battery panel monitoring unit 25, and a housing 20A that houses these components.

[0034] The battery panel monitoring unit 25 includes a control device 26, a memory unit 27, a display unit 28, and a DC power supply unit 29. The battery panel monitoring unit 25 collects information from within the battery panel and communicates with the PCS panel 30 and the remote monitoring device 100.

[0035] The power storage bank 21 is composed of a plurality of power storage modules 60 connected in series, a current sensor 63, a fuse 64, a relay SW, a bank monitoring device 65, and a plurality of module monitoring devices 70. The current sensor 63 measures the current of the power storage bank 21, and the relay SW cuts off the current of the power storage bank 21.

[0036] 3, the power storage module 60 is a unit formed by fixing a plurality of power storage cells 61 connected in series to a frame 62. Various types of cells can be used as the power storage cells 61, such as non-aqueous electrolyte secondary battery cells such as lithium ion secondary batteries, capacitors, NAS battery cells, and redox flow battery cells, as long as they are capable of storing electricity (capable of repeated charging and discharging).

[0037] When the energy storage system 10 has multiple battery panels 20, the battery types of the battery panels 20 may be the same or different. For example, all the battery panels 20 may be made of lithium-ion secondary batteries, or a combination of battery panels 20 made of lithium-ion secondary batteries and battery panels 20 made of NAS may be used.

[0038] A module monitoring device 70 is provided for each power storage module 60. The module monitoring device 70 monitors the temperature of the power storage module 60 and the cell voltage of each power storage cell 61.

[0039] The bank monitoring device 65 performs integrated management of the number of series connections and communication status of the module monitoring devices 70, and monitors the power storage bank 21. For example, the bank monitoring device 65 monitors the current of the power storage modules 60 based on the measurement value of the current sensor 63, and monitors the temperature of each power storage module 60 and the cell voltage of each power storage cell 61 through communication with the module monitoring device 70.

[0040] The power storage bank 21 is connected to a power line (main circuit) L0 via a fuse 64 and a relay SW. The power storage bank 21 may have a single bank configuration or a multiple bank configuration. Fig. 2 shows a three-bank configuration.

[0041] 4 is a diagram showing a communication system between the bank monitoring device 65 and the module monitoring device 70. The bank monitoring device 65 includes a CPU 66, a communication IC 67, a pulse transformer 68, and a memory unit 69.

[0042] The module monitoring device 70 includes a pulse transformer 71, a monitoring IC 75, and an EEPROM 76. The monitoring IC 75 has a function of monitoring and communicating with the power storage cells 61. The EEPROM 76 stores information such as the serial number of the monitoring IC 75, the number of cells in the power storage module 60, and the type of the cells 61.

[0043] The bank monitoring device 65 and the multiple module monitoring devices 70 are daisy-chained via a communication line L. A daisy-chain connection is a form in which multiple devices are connected in a daisy-chain fashion, and is also called a cascade connection. Figure 4 shows an example in which three module monitoring devices 70 are daisy-chained (number of series = 3). The number of connections is just an example, and may be any number other than 3.

[0044] The bank monitoring device 65 communicates with each module monitoring device 70 via a bucket brigade network (specifically, insulated two-wire differential SPI communication). SPI is an abbreviation for Serial Peripheral Interface.

[0045] In this communication method, the CPU 66 of the bank monitoring device 65 communicates directly with the monitoring IC 75 of the module monitoring device 70 via the communication IC 67, pulse transformer 68, and pulse transformer 71. This eliminates the need for a CPU or its peripheral circuits (such as a power supply circuit and reset circuit for the CPU) in the module monitoring device 70, thereby reducing the cost of the module monitoring device 70. Furthermore, the use of pulse transformers 68 and 71, which have essentially no lifespan, improves long-term reliability compared to using photocouplers, which have a finite lifespan. Electrical isolation between the bank monitoring device 65 and the module monitoring device 70 ensures user safety (electric shock protection). In particular, in this example, the use of two pulse transformers 68 and 71 allows the remote monitoring panel 50 to be double-insulated against the battery voltage of the power storage bank 21.

[0046] 5 shows the startup flow of the communication ICs 67, 75A, 75B, and 75C of the power storage bank 21. The vertical axis represents time. The square K1 indicates the startup process of the communication ICs, and the square K2 indicates the process of assigning device addresses to the communication ICs.

[0047] The communication ICs start with a start command sent from the CPU 66 to the communication IC 67, and then start commands are sent in sequence between the ICs, thereby starting up the ICs 75A, 75B, and 75C in sequence.

[0048] Specifically, the CPU 66 first starts the communication IC 67 in response to a start-up instruction. Thereafter, the CPU 66 again sends a start-up command to the communication IC 67 to start the monitoring IC, causing the communication IC 67 to start the second-stage monitoring IC 75A. Similarly, the second-stage monitoring IC 75A starts the third-stage monitoring IC 75B, and the third-stage monitoring IC 75B starts the fourth-stage monitoring IC 75C.

[0049] The device addresses are assigned after all ICs 67, 75A to 75C are started up. Specifically, first, the CPU 66 sets a device address (for example, the total number of communication ICs) for the communication IC 67. The communication IC 67 subtracts 1 from the device address and transmits the resulting device address to the next monitoring IC 75A and assigns it to the next monitoring IC 75A.

[0050] In this way, the IC can assign consecutive device addresses by subtracting one from the device address and sending it to the next IC.

[0051] In the example of FIG. 6, the total number of communication ICs is four, and device addresses 4, 3, 2, and 1 can be assigned to the communication IC 67, the monitoring IC 75A, the monitoring IC 75B, and the monitoring IC 75C in that order.

[0052] The device address of the monitoring IC 75C is determined after transmitting an ACK to the monitoring IC 75B. The other monitoring ICs, 75B, 75A, and the communication IC 67, are determined after receiving an ACK from the monitoring ICs 75C, 75B, and 75A, or after the daisy chain communication times out. The ACK is a confirmation signal that indicates that communication has been completed successfully.

[0053] In the following description, the bank monitoring device 65 is referred to as the master device, and the module monitoring devices 70A to 70C are referred to as slave devices, as shown in Figure 6. Of the slave devices 70A to 70C, the one closest to the master device 65 in the communication transmission direction is referred to as the lower tier, and the one furthest from it is referred to as the upper tier, with the top device being referred to as the top device.

[0054] 2. Regarding the number of series Q of the slave devices 70 The number of series Q of the slave devices 70 may differ depending on the scale and specifications of the energy storage system 10. If the number of series Q of the slave devices 70 differs from the expected design value due to a harness connection error, a communication circuit failure, or the like during battery panel assembly, and this cannot be detected, it may lead to an unsafe event.

[0055] In this embodiment, when the communication IC of the power storage bank 21 is started up (including the initial start-up after on-site installation of the energy storage system, start-up after power-on, start-up by resetting, restart, etc.), the abnormality determination sequence shown in FIG. 7 is executed to determine whether the connection state of the slave device 70 is good or bad.

[0056] In order to execute the abnormality determination sequence shown in FIG. 7, the master device (CPU 66) stores an execution program for the abnormality detection sequence and the following information in the storage unit 69.

[0057] The design value of the number Q of serial connections of the slave devices 70. The maximum number Qmax of serial connections of the slave devices 70 (the maximum value that can be connected in series based on the product specifications, etc.).

[0058] 7 is made up of the processes of S10 to S60. <Device Address Assignment> When the abnormality determination sequence starts, the master device (CPU 66) writes the total number of devices N to the register 67A of the communication IC 67 in S10.

[0059] N=(Qmax+1)+1 (1) Qmax is the maximum number of serial connections for the slave devices 70. (Qmax+1) indicates the maximum number of serial connections for all devices, including the maximum number of serial connections for the slave devices 70 and the master device 65.

[0060] The reason for adding 1 to the maximum number of serial connections (Qmax+1) of all devices on the right side of equation (1) is to determine if the number of serial connections Q of the slave device 70 exceeds the maximum number of serial connections Qmax.

[0061] The master device 65 assigns consecutive device addresses to all communication ICs when the ICs are started. Specifically, addresses obtained by subtracting 1 from the total number of devices N are assigned to each device from the master device 65 to the top device 70 in the uppermost row. The procedure for assigning and determining device addresses is as described with reference to FIGS. 5 and 6.

[0062] <Response Confirmation> After the device addresses have been determined, the process proceeds to S20, where the master device 65 performs response confirmation on the slave devices 70 in order, starting with device address 1. The response confirmation determines whether communication is normal, and is confirmed by checking whether an ACK is returned in response to the transmission of the response confirmation signal. When response confirmation has been completed for all slave devices 70 to which addresses have been assigned, the process proceeds to S30.

[0063] <Calculation of Serial Number Q> When the process proceeds to S30, the master device 65 detects the serial number Q of the slave devices 70 by subtracting the device address with which communication was first established in S20 from the total number of devices N set in S10.

[0064] 8, if the total number of devices N is 27 (the maximum number of serial slave devices 70 is Qmax=25) and the actual number of serial slave devices 70 is 4, communication is not possible from device addresses 1 to 22, but communication is possible from device address 23. Therefore, the number of serial slave devices 70 can be calculated as Q=27-23, which is 4.

[0065] After detecting the serial number Q, the master device 65 shuts down and restarts the monitoring IC 75 of the slave device 70. Then, the master device 65 assigns a new device address with the serial number Q calculated in S30 (see FIG. 9). Even if the serial number Q of the slave device 70 changes, the serial number Q of the slave device 70 can be calculated using the above method.

[0066] <Determining Connection Status> Then, the process proceeds to S40, where the master device 65 can determine whether the number Q of serial connections of the slave devices 70 calculated in S30 is abnormal by comparing it with a design value.

[0067] Specifically, if the number of series Q detected in S30 matches the design value, it can be determined that there is no connection error or communication circuit failure and that the system is normal (S50).

[0068] If the number Q of series connections calculated in S30 is less than the design value, it can be determined that some abnormality has occurred in the communication system, such as a connection error or a communication circuit failure (S60).

[0069] If the number of series Q calculated in S30 is greater than the design value, it can be determined that more slave devices 70 are connected than the design value (S60).

[0070] 4. Effects This configuration makes it possible to detect the serial number Q of the slave device 70 using the device address, and by comparing this with a set value, it is possible to confirm from the comparison result whether the slave device 70 is connected correctly and whether the communication system IC is operating normally.

[0071] <Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0072] (1) In the above embodiment, the present technology is applied to the communication system of the power storage bank 21 to detect the number Q of serial connections of the module monitoring device 70. However, the present technology can also be applied to communication systems other than power storage banks as long as they are daisy-chain connected. This technology is particularly effective when the number of serial connections of slave devices varies from case to case.

[0073] (2) In the above embodiment, device addresses are assigned by subtracting 1 from the total number of devices N (in descending order) from the bank monitoring device 65 to the top device 70C. The device addresses only need to be consecutive, and for example, they may be assigned by adding 1 each (in ascending order) from the bank monitoring device 65 to the top device 70C.

[0074] (3) In the above embodiment, the bank monitoring device 65 confirmed the responses of the slave devices 70 in ascending order of device addresses. However, the bank monitoring device 65 may confirm the responses in descending order of device addresses.

[0075] (4) The present technology is not limited to the above embodiment, and may include one master device and multiple slave devices, and may perform the following in a configuration in which the master device and the multiple slave devices are daisy-chained via a communication line: (a) the master device assigns consecutive device addresses to all devices, and then performs response confirmation for each of the multiple slave devices through communication via the communication line; and (b) the master device detects the serial number of the slave device based on the device address of the slave device whose response confirmation was successful, and compares the detected serial number with a set value.

[0076] REFERENCE SIGNS LIST 1 Power system 10 Energy storage system 20 Battery panel 21 Power storage bank 65 Bank monitoring device (master device) 66 CPU 67 Communication IC 68 Pulse transformer 70 Module monitoring device (slave device) 71 Pulse transformer 75 Monitoring IC

Claims

1. A device apparatus comprising one master device and multiple slave devices, the master device and the multiple slave devices being daisy-chained via a communication line, the master device assigning consecutive device addresses to all devices and then confirming responses from each of the multiple slave devices via communication via the communication line, the master device detecting the serial number of the slave devices based on the device addresses of the slave devices whose responses have been successfully confirmed, and comparing the detected serial number with a set value.

2. A device system according to claim 1, wherein the master device sets a total number of all devices connected in a daisy chain based on the maximum serial number of the slave devices, the master device assigns device addresses to all devices connected in the daisy chain, each of which is obtained by subtracting one from the total number of devices, in order from the master device to the top device of the slave devices, the master device confirms responses from the slave devices connected in the daisy chain in ascending order of device addresses, and the master device calculates the serial number of the slave devices by subtracting the device address of the slave device whose response was first successfully confirmed from the total number of devices.

3. The device system according to claim 2, wherein the total number of devices is a value obtained by adding two to the maximum number of serial connections of the slave devices.

4. A device for monitoring a power storage bank according to claim 1 or 2, wherein the power storage bank includes a plurality of power storage modules, the slave device is a monitoring device for the power storage modules, and the master device is a monitoring device for the power storage bank.

5. An energy storage system comprising: a PCS panel accommodating a power conversion unit; and a battery panel accommodating a power storage bank connected to the power conversion unit via a power line, wherein the power storage bank comprises: a plurality of power storage modules connected in series; a module monitoring device for monitoring the power storage modules; and a bank monitoring device, wherein the bank monitoring device and the plurality of module monitoring devices are daisy-chained via a communication line, and the bank monitoring device assigns consecutive device addresses to all monitoring devices and then confirms responses from each of the plurality of module monitoring devices via communication via the communication line, and the bank monitoring device detects the number of series of the module monitoring devices based on the device addresses of the module monitoring devices whose responses have been successfully confirmed, and compares the detected number of series with a set value.

6. An energy storage system according to claim 5, wherein the bank monitoring device detects the number of series of the module monitoring devices and compares the number with a set value when the energy storage system is first started up.

7. An energy storage system according to claim 5 or 6, comprising a plurality of storage battery panels each having a different battery type.

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