Storage battery control device and power storage system

Abstract

To meet a request about responsibility of a power storage system having a plurality of power storage strings connected in parallel, with respect to a command from a higher-level system.SOLUTION: A storage battery control device 2 includes a plurality of string controllers SC1 to SCx that are provided for respective strings St1 to Stx and control the corresponding strings St1 to Stx, and a string system controller SSC that exchanges a data frame with the plurality of string controllers SC1 to SCx at prescribed cycles. The data frame includes a base data field to which base information exchanged at the prescribed cycles is allocated, and an event data field to which event information exchanged at an occurrence time of an event is allocated. The same type of base information is allocated to the event data field at every prescribed cycle. The event data field has a capacity smaller than that of the base data field, and a different type of event information is allocated to the event data field at each of the prescribed cycles.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a battery control device and a power storage system. [Background technology]

[0002] There is known a power storage system in which a plurality of assembled batteries are connected in parallel to a power supply target and a power grid via a plurality of power conditioning systems (PCSs) (see, for example, Patent Document 1). The power storage system described in Patent Document 1 includes an energy management system (EMS), a plurality of battery management units (BMUs), a plurality of state of charge (SOC) sensors, and the like. The EMS transmits a power instruction value to one of the plurality of BMUs, a master BMU. The master BMU sets charge / discharge instruction values ​​for all assembled batteries, and transmits the set charge / discharge instruction values ​​to all slave BMUs. Each slave BMU controls the charge / discharge amount of each assembled battery based on the received charge / discharge instruction value and the SOC of the assembled battery estimated by SOC estimation.

[0003] Also, as a system for controlling the discharge of a storage string in which multiple storage batteries are connected in series, a system is known that bypasses a storage battery that cannot discharge the required current and discharges the other storage batteries (see, for example, Patent Document 2). Furthermore, as a system for controlling the charging of a storage string in which multiple storage batteries are connected in series, a system is known that bypasses a storage battery that cannot charge the input current and charges the other storage batteries (see, for example, Patent Document 3). The storage systems described in Patent Documents 2 and 3 include a first switch that connects or disconnects the storage batteries, and a second switch that connects or disconnects the bypass line. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-167928 A [Patent Document 2] JP 2013-31247 A [Patent Document 3] JP 2013-31249 A Summary of the Invention [Problem to be solved by the invention]

[0005] If the battery pack of the energy storage system described in Patent Document 1 is used as the energy storage string of the systems described in Patent Documents 2 and 3, complex charge and discharge control is required, which results in a huge amount of communication between the control devices and long communication times. As a result, responsiveness to charge and discharge instructions from the upper system is sacrificed, making it difficult to control the power receiving point, which requires a high-speed response.

[0006] In view of the above circumstances, the present invention aims to provide a battery control device and a power storage system in which multiple power storage strings are connected in parallel, which meet the requirements for responsiveness to instructions from a higher-level system. [Means for solving the problem]

[0007] The battery control device of the present invention is a battery control device that controls a battery system having a plurality of storage strings connected in parallel, and includes a plurality of first control units provided for each of the storage strings and controlling the corresponding storage string, and a second control unit that transmits and receives data frames with the plurality of first control units at a predetermined period, the data frame includes a first data area to which first information to be transmitted and received at the predetermined period is assigned, and a second data area to which second information to be transmitted and received when an event occurs is assigned, the first data area being assigned the same type of first information at the predetermined period, and the second data area having a smaller capacity than the first data area and being assigned a different type of second information at the predetermined period.

[0008] The energy storage system of the present invention is an energy storage system comprising a plurality of energy storage strings connected in parallel, and a battery control device that controls the plurality of energy storage strings, wherein the battery control device is provided for each of the energy storage strings, and comprises a plurality of first control units that control the corresponding energy storage strings, and a second control unit that transmits and receives data frames with the plurality of first control units at a predetermined period, wherein the data frame comprises a first data area to which first information that is transmitted and received at the predetermined period is assigned, and a second data area to which second information that is transmitted and received when an event occurs is assigned, wherein the first data area is assigned the same type of first information at the predetermined period, and the second data area has a smaller capacity than the first data area, and is assigned a different type of second information at the predetermined period. Effect of the Invention

[0009] According to the present invention, in a power storage system in which a plurality of power storage strings are connected in parallel, it is possible to satisfy the requirement for responsiveness to instructions from a higher-level system. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a circuit diagram showing a circuit configuration of a power storage system including a battery control device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a control configuration of the power storage system shown in FIG. [Diagram 3] FIG. 3 is a flowchart for explaining the processing of the string system controller shown in FIG. 1 and FIG. [Figure 4] FIG. 4 is a diagram showing the structure of a data frame transmitted in CAN communication between the string system controller and a plurality of string controllers of the battery control device shown in FIGS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and the embodiments can be appropriately modified within the scope of the present invention. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but for the details of the omitted technologies, publicly known or well-known technologies are appropriately applied within the scope of not causing any contradiction with the contents described below.

[0012] Fig. 1 is a circuit diagram showing the circuit configuration of a power storage system 1 including a battery control device 2 (see Fig. 2) according to one embodiment of the present invention. The power storage system 1 shown in this figure is a stationary power source, and includes a string system 10 and a power storage system controller PSC.

[0013] The power storage system controller PSC is the highest hierarchical control device in the power storage system 1, and communicates with the upper server 7 (see FIG. 2) and the string system controller SSC to control the power storage system auxiliary devices 3 (see FIG. 2). The power storage system controller PSC also includes a display / input device (not shown) such as a touch panel having a display function and an input function.

[0014] The string system 10 includes a plurality of strings St1 to Stx, a string bus 6, a string system controller SSC, and a plurality of string controllers SC1 to SCx. The string system controller SSC and the string controllers SC1 to SCx will be described later.

[0015] The multiple strings St1 to Stx are connected in parallel to each other and to an external system (not shown) via a string bus 6. Each of the strings St1 to Stx includes a power converter PCS1 to PCSx, a string cutoff switch 11, multiple modules M1 to Mm, and multiple module controllers MC1 to MCm. The module controllers MC1 to MCm will be described later.

[0016] Each of the modules M1-Mm includes a storage battery B1-Bm, a bypass switch unit BSU1-BSUm, and a voltage sensor 12. In each of the strings St1-Stx, a plurality of storage batteries B1-Bm are connected in series, and a bypass switch unit BSU1-BSUm is provided for each of the storage batteries B1-Bm. Each of the strings St1-Stx also includes a current sensor 13, a voltage sensor 14, a fuse 15, the same number of temperature sensors (not shown) as the number of storage batteries B1-Bm, and the same number of cell voltage sensors (not shown) as the number of storage battery cells.

[0017] The storage batteries B1 to Bm are secondary batteries such as lithium ion batteries and lithium ion capacitors, and are charged by receiving power from an external system via the power converters PCS1 to PCSx, and the charged power is discharged via the power converters PCS1 to PCSx to supply power to the external system. Although not particularly limited, the storage batteries B1 to Bm in this embodiment are regenerated second-hand storage batteries, and there is a difference in the degree of deterioration of each of the storage batteries B1 to Bm. Note that the storage batteries B1 to Bm may be storage battery packs in which a plurality of storage battery modules are connected in series, or may be composed of a single storage battery cell.

[0018] Each of the bypass switch units BSU1 to BSUm includes a bypass line BL and switches S1 and S2. The bypass line BL is a power line that bypasses each of the storage batteries B1 to Bm. The switch S1 is provided on the bypass line BL. The switch S1 is, for example, a mechanical switch, a semiconductor switch, or a relay. The switch S2 is provided between the positive electrode of each of the storage batteries B1 to Bm and one end of the bypass line BL. The switch S2 is, for example, a mechanical switch, a semiconductor switch, or a relay.

[0019] The starting battery B1 and the ending battery Bm are connected to an external system via power converters PCS1-PCSx and a string bus 6. When the switch S1 is turned OFF and the switch S2 is turned ON in all of the bypass switch units BSU1-BSUm, all of the batteries B1-Bm are connected in series to the external system. On the other hand, when the switch S2 is turned OFF and the switch S1 is turned ON in any of the bypass switch units BSU1-BSUm, the battery B1-Bm corresponding to that bypass switch unit BSU1-BSUm is bypassed.

[0020] The power converters PCS1 to PCSx are bidirectional converters, and are connected to a string bus 6. Furthermore, the positive electrode of the starting storage battery B1 and the negative electrode of the terminal storage battery Bm are connected to each of the power converters PCS1 to PCSx.

[0021] When charging the strings St1-Stx, the power converters PCS1-PCSx convert the voltage input from the string bus 6 according to the string charging power instruction value and output the converted voltage to the multiple storage batteries B1-Bm. Here, the voltage on the side of the strings St1-Stx changes according to the bypass state of the storage batteries B1-Bm (the number of bypassed storage batteries B1-Bm) and the charging state of the storage batteries B1-Bm. Therefore, when charging the strings St1-Stx, the power converters PCS1-PCSx convert the voltage input from the string bus 6 to the voltage on the side of the strings St1-Stx and output the converted voltage to the multiple storage batteries B1-Bm.

[0022] When the strings St1 to Stx are discharged, the power converters PCS1 to PCSx convert the voltages input from the batteries B1 to Bm according to the string discharge power instruction value and output the converted voltage to the string bus 6. Here, the input voltage of the power converters PCS1 to PCSx during discharge varies according to the bypass state of the batteries B1 to Bm and the charge state of the batteries B1 to Bm. This causes variations in the input voltages of the power converters PCS1 to PCSx among the strings St1 to Stx during discharge. Therefore, when the strings St1 to Stx are discharged, the power converters PCS1 to PCSx convert the input voltage to a voltage that matches the other strings St1 to Stx and output the converted voltage to the string bus 6. When the current flowing through the string bus 6 is AC, the power converters PCS1 to PCSx are provided with a synchronization means for following changes in the instantaneous value.

[0023] Each string cutoff switch 11 is provided between each power converter PCS1 to PCSx and the string bus 6. The string cutoff switch 11 connects or disconnects the strings St1 to Stx to the string bus 6. In addition, each fuse 15 is a power fuse provided between each string cutoff switch 11 and the string bus 6.

[0024] The voltage sensor 12 is connected between the positive and negative terminals of each of the storage batteries B1-Bm, detects the terminal voltage of each of the storage batteries B1-Bm, and transmits a detection signal to each of the module controllers MC1-MCm. The current sensor 13 is provided on the power line PL of each of the strings St1-Stx, detects the charge / discharge current of each of the strings St1-Stx (hereinafter, string current), and transmits a detection signal to each of the string controllers SC1-SCx. The voltage sensor 14 is provided on the power line PL of each of the strings St1-Stx, detects the total voltage of each of the strings St1-Stx (hereinafter, string total voltage), and transmits a detection signal to each of the string controllers SC1-SCx.

[0025] A temperature sensor is provided in each of the batteries B1-Bm to detect the temperature of the batteries B1-Bm and transmit a detection signal to the module controllers MC1-MCm. A cell voltage sensor is provided in each of the batteries B1-Bm to detect the voltage of each battery cell and transmit a detection signal to the module controllers MC1-MCm.

[0026] Fig. 2 is a block diagram showing a control configuration of the power storage system 1 shown in Fig. 1. As shown in this figure, the power storage system 1 includes a storage battery control device 2. The storage battery control device 2 includes a plurality of first control devices 21 and a second control device 22. Each of the first control devices 21 includes string controllers SC1 to SCx and a plurality of module controllers MC1 to MCm. The second control device 22 includes a power storage system controller PSC and a string system controller SSC.

[0027] The power storage system controller PSC, the string system controller SSC, the string controllers SC1 to SCx, and the module controllers MC1 to MCm are provided for each hierarchical level. The power storage system controller PSC corresponds to the hierarchical level of the top power storage system 1. The string system controller SSC corresponds to the hierarchical level of the string system 10 which is next to the hierarchical level of the power storage system 1. The string controllers SC1 to SCx correspond to the hierarchical level of the strings St1 to Stx which is next to the hierarchical level of the string system 10. The module controllers MC1 to MCm correspond to the hierarchical level of the modules M1 to Mm (see FIG. 1) which is next to the hierarchical level of the strings St1 to Stx.

[0028] In this embodiment, the communication standard for the hierarchy below the string system controller SSC is CAN (Control Area Network). Note that other communication standards such as LIN (Local Interconnect Network) may be adopted instead of CAN. Also, in this embodiment, the communication standard between the string system controller SSC and the power storage system controller PSC is Ethernet (registered trademark), and protocol conversion is performed between the power storage system controller PSC and the string system controller SSC. Note that other communication standards such as CAN may be adopted instead of Ethernet.

[0029] The power storage system controller PSC communicates with the host server 7 and the string system controller SSC to control and manage the power storage system auxiliaries 3. The host server 7 is provided in an aggregator facility, or in a power receiving facility of a building, factory, etc. This host server 7 calculates a charge / discharge power instruction value for the entire power storage system 1 (hereinafter, the power storage system charge / discharge power instruction value) according to the state of the power storage system 1 and the power demand, and transmits it to the power storage system controller PSC.

[0030] The power storage system accessories 3 include a temperature sensor that detects the temperature of the installation environment of the power storage system 1, such as a container, and a fire extinguishing system (both not shown). If the detected value of the temperature sensor exceeds a threshold, the power storage system controller PSC determines that the temperature of the installation environment of the power storage system 1 is abnormal, and outputs an abnormality notification to the display input device. In addition, the power storage system controller PSC monitors the operating state of the fire extinguishing system.

[0031] The storage system controller PSC receives information about the states of the strings St1 to Stx (hereinafter, string state information) and information about the state of the string system 10 (hereinafter, string system state information) from the string system controller SSC, and outputs it to the upper server 7 and the display input device.

[0032] The states of strings St1 to Stx include operating states such as charging, discharging, suspension, maintenance, etc., string current, total string voltage, SOC of strings St1 to Stx (hereinafter, string SOC), SOH (State of Health) of strings St1 to Stx (hereinafter, string SOH), and limit values ​​of charge / discharge power (or charge / discharge current) of strings St1 to Stx (hereinafter, string charge / discharge power limit values).

[0033] The state of the string system 10 may include the current of the string bus 6 (see FIG. 1) (hereinafter, string bus current), the voltage of the string bus 6 (hereinafter, string bus voltage), the SOC of the string system 10 (hereinafter, string system SOC), the SOH of the string system 10 (hereinafter, string system SOH), and the limit value of the charge / discharge power (or charge / discharge current) of the string system 10 (hereinafter, string system charge / discharge power limit value).

[0034] The power storage system controller PSC estimates the state of the power storage system 1 based on the string state information and the string system state information received from the string system controller SSC. Examples of the state of the power storage system 1 include an operating state such as charging, discharging, suspension, and maintenance, the SOC of the power storage system 1 (hereinafter, power storage system SOC), and the SOH of the power storage system 1 (hereinafter, power storage system SOH). The power storage system controller PSC outputs information on the estimated state of the power storage system 1 (hereinafter, power storage system state information) to a display input device (not shown) as necessary. Note that in this embodiment in which there is a single string system 10, the string system SOC is equal to the power storage system SOC, and the string SOH is equal to the power storage system SOH.

[0035] The power storage system controller PSC transmits information required for the processing of the upper server 7 to the upper server 7. Examples of information required for the processing of the upper server 7 include the power storage system SOC, the power storage system SOH, and the string system charge / discharge power limit value. Here, the upper server 7 determines a charge / discharge instruction corresponding to the power storage system 1 based on the "information required for the processing of the upper server 7" received from the power storage system controller PSC, and transmits the charge / discharge instruction to the power storage system controller PSC. Examples of the charge / discharge instruction include, in addition to the power storage system charge / discharge power instruction value, control amounts such as a constant voltage (CV) mode, a constant current (CC) mode, and a constant power (CP) mode, and an operation method such as an independent operation or a grid-connected operation.

[0036] The power storage system controller PSC transmits various instruction information inputted by an operator or the like via the display input device to the string system controller SSC. Examples of various instruction information that can be inputted via the display input device include an instruction to execute a maintenance / stop mode (hereinafter, a maintenance / stop instruction), an instruction to forcibly execute charging / discharging, an instruction to forcibly execute a state estimation, an instruction to display string state information on the display input device, and the like.

[0037] Examples of the maintenance / stop instruction include an instruction to forcibly operate the power storage system auxiliary device 3, the string system auxiliary device 4, and the string auxiliary device 5. By forcibly operating the power storage system auxiliary device 3, the string system auxiliary device 4, and the string auxiliary device 5, it is possible to check the operation of the power storage system auxiliary device 3, the string system auxiliary device 4, and the string auxiliary device 5. Inputting a maintenance / stop instruction to the display input device corresponds to an event.

[0038] An example of an instruction to forcibly execute charging / discharging is an instruction to forcibly execute charging / discharging in the power storage system 1 by specifying a predetermined charging / discharging amount. By forcibly executing charging / discharging in the power storage system 1 by specifying a predetermined charging / discharging amount, it is possible to check whether the power storage system 1 can charge / discharge the specified predetermined amount. Inputting an instruction to forcibly execute charging / discharging into the display / input device corresponds to an event.

[0039] An example of an instruction to forcibly execute state estimation is an instruction to forcibly execute state estimation in the power storage system 1 by specifying a predetermined item of state estimation. By forcibly executing state estimation in the power storage system 1 by specifying a predetermined item of state estimation, it becomes possible to acquire state estimation items such as the string system SOH and the power storage system SOH at any time. Inputting an instruction to forcibly execute state estimation into the display input device corresponds to an event. Furthermore, inputting an instruction to display string state information on the display input device into the display input device corresponds to an event.

[0040] The string system controller SSC communicates with the power storage system controller PSC and the multiple string controllers SC1 to SCx, and controls and manages the string system auxiliaries 4. The string system auxiliaries 4 include a temperature sensor that detects the ambient temperature, a cooling device in the string system 10, a circuit breaker for the string bus 6, a current sensor that detects the string bus current, a voltage sensor that detects the string bus voltage, and the like (all of which are omitted from the drawing).

[0041] The string system controller SSC receives string state information from the string controllers SC1 to SCx, and estimates the state of the string system 10 based on the received string state information. Note that the estimation of the state of the string system 10 may be performed by the power storage system controller PSC. The power storage system controller PSC may receive string state information from the string system controller SSC, estimate the state of the string system 10, and estimate the state of the power storage system 1 based on the estimation result.

[0042] For example, when the detected values ​​of the temperature sensor, the current sensor, and the voltage sensor or the estimated value of the state of the string system 10 exceed the threshold range, the string system controller SSC determines whether or not there is an abnormality in the string system 10, and stops the operation of the string system 10 or transmits an abnormality notification to the power storage system controller PSC. An abnormality in the string system 10 corresponds to an event.

[0043] The string system controller SSC transmits to the power storage system controller PSC information required for processing by the power storage system controller PSC among the information received from the string controllers SC1 to SCx and information estimated by itself. Examples of information required for processing by the power storage system controller PSC include the string system SOC, the string system SOH, and the string system charge / discharge power limit value.

[0044] Here, the power storage system controller PSC determines an instruction corresponding to the string system 10 based on "information required for processing by the power storage system controller PSC" received from the string system controller SSC, and transmits the instruction information to the string system controller SSC. Examples of the instruction include a charge / discharge instruction for the string system 10 in the charge / discharge mode, an instruction to individually control each part of the string system 10 in the maintenance mode (hereinafter referred to as an individual control instruction), and a state estimation instruction for the string system 10 in the state estimation mode. Examples of the charge / discharge instruction for the string system 10 in the charge / discharge mode include, in addition to string charge / discharge power instruction values ​​to be assigned to each string St1 to Stx, control amounts for constant voltage (CV) mode, constant current (CC) mode, and constant power (CP) mode, and instructions for operation methods such as independent operation / grid connection, etc. Examples of the individual control instruction for the string system 10 in the maintenance mode include an instruction to individually control the string system auxiliaries 4 such as the power converters PCS1 to PCSx, the cooling device, and the switches S1 and S2 (see FIG. 1). The state estimation instruction to the string system 10 in the state estimation mode includes an instruction to execute predetermined control necessary to estimate the state of each of the strings St1 to Stx. The individual control instruction to the string system 10 in the maintenance mode and the state estimation instruction to the string system 10 in the state estimation mode correspond to events.

[0045] The string system controller SSC receives an instruction corresponding to the above-mentioned string system 10 from the power storage system controller PSC, and judges whether or not the operation state of the string system 10 needs to be updated by comparing the instruction received this time with the instruction received last time. If the operation state of the string system 10 needs to be updated, the string system controller SSC determines the operation mode of each of the strings St1 to Stx, permission for a bypass request from each of the string controllers SC1 to SCx (hereinafter, bypass permission), and a string charge / discharge power instruction value to be assigned to each of the strings St1 to Stx. Examples of the operation mode of each of the strings St1 to Stx include a charge / discharge mode, a state estimation mode, and a maintenance / stop mode.

[0046] Here, the string system controller SSC determines the operation mode, bypass permission, and string charge / discharge power instruction value of each string St1 to Stx based on the operation history from the past to the present of each string St1 to Stx. Examples of the determination of the operation mode, etc. based on the operation history from the past to the present include the following (1) to (4). (1) Whether or not to perform state estimation for each of the strings St1 to Stx is determined based on the implementation timing of state estimation for each of the strings St1 to Stx. (2) Based on whether or not and when an abnormality is determined for each of the strings St1 to Stx, it is determined whether to perform maintenance on each of the strings St1 to Stx or whether to charge and discharge each of the strings St1 to Stx. (3) Depending on the presence or absence of a bypass request from each of the string controllers SC1 to SCx, the string charge / discharge power instruction value of each of the strings St1 to Stx is determined. For example, the string charge / discharge power instruction value of the strings St1 to Stx corresponding to the string controllers SC1 to SCx that have transmitted the bypass request is determined to be 0. After the bypass control of the strings St1 to Stx is completed, the string charge / discharge power instruction value for the strings St1 to Stx is increased. (4) A string charge / discharge power instruction value for each of the strings St1 to Stx is determined based on the string SOC, string SOH, and string total voltage of each of the strings St1 to Stx.

[0047] The string controllers SC1 to SCx communicate with the string system controller SSC and multiple module controllers MC1 to MCm, and control and manage the string auxiliaries 5. The string auxiliaries 5 include power converters PCS1 to PCSx, a current sensor 13 that detects a string current, a voltage sensor 14 that detects a total string voltage, a string cutoff switch 11, and the like (all see FIG. 1).

[0048] The string controllers SC1 to SCx receive information on the state of each of the modules M1 to Mm (hereinafter, module state information) from the module controllers MC1 to MCm. The state of each of the modules M1 to Mm includes the temperature, current, voltage, and cell voltage of the storage batteries B1 to Bm, and the state of the bypass switch units BSU1 to BSUm.

[0049] The string controllers SC1-SCx estimate the SOC, SOH, charge / discharge power limit value, etc. of the storage batteries B1-Bm based on the module state information received from the module controllers MC1-MCm. The SOC, SOH, charge / discharge power limit value, etc. of the storage batteries B1-Bm may be estimated by the module controllers MC1-MCm. In this case, the module controllers MC1-MCm may transmit the estimation results to the string controllers SC1-SCx.

[0050] The string controllers SC1 to SCx estimate the states of the strings St1 to Stx based on the module state information received from the module controllers MC1 to MCm. Examples of the states of the strings St1 to Stx include the string SOH, the string SOC, and the string charge / discharge power limit value. The states of the strings St1 to Stx may be estimated by the string system controller SSC. In this case, the string controllers SC1 to SCx may transmit the module state information and the estimated results of the states of the storage batteries B1 to Bm to the string system controller SSC.

[0051] For example, when the detection values ​​of the current sensor 13 and the voltage sensor 14 or the estimated values ​​of the states of the strings St1 to Stx are outside the threshold range, the string controllers SC1 to SCx determine whether or not there is an abnormality in the strings St1 to Stx. In this case, the string controllers SC1 to SCx stop the operation of the strings St1 to Stx or transmit an abnormality notification to the string system controller SSC. The abnormality in the strings St1 to Stx corresponds to an event.

[0052] The string controllers SC1 to SCx transmit to the string system controller SSC information required for processing of the string system controller SSC among the information received from the module controllers MC1 to MCm and the information estimated by themselves. The information required for processing of the string system controller SSC includes the temperature, current, voltage, SOC, SOH, charge / discharge power limit value, cell voltage, state of the bypass switch units BSU1 to BSUm, string SOC, string SOH, string charge / discharge power limit value, etc. of the storage batteries B1 to Bm.

[0053] Here, the string system controller SSC determines instructions corresponding to each of the strings St1 to Stx based on "information required for processing by the string system controller SSC" received from the string controllers SC1 to SCx, and transmits instruction information to the string controllers SC1 to SCx. Examples of these instructions include charge / discharge instructions for each of the strings St1 to Stx in the charge / discharge mode, individual control instructions for each of the strings St1 to Stx in the maintenance mode, and state estimation instructions for each of the strings St1 to Stx in the state estimation mode. Items of the charge / discharge instructions for each of the strings St1 to Stx in the charge / discharge mode include, in addition to the string charge / discharge power instruction value, the control amount of the constant voltage mode, the constant current mode, and the constant power mode, and the operation method such as independent operation / grid connection. Items of the individual control instructions for each of the strings St1 to Stx in the maintenance mode include instructions to individually control the bypass switch units BSU1 to BSUm. Items of the state estimation instructions in the state estimation mode include, for example, charging / discharging at a constant current and recording the terminal voltage of the storage batteries B1 to Bm at that time. An instruction to individually control each of the strings St1 to Stx in the maintenance mode and an instruction to estimate the state in the state estimation mode correspond to events.

[0054] The string controllers SC1 to SCx receive instruction information corresponding to each of the strings St1 to Stx from the string system controller SSC, and determine whether or not the bypass schedule of each of the strings St1 to Stx needs to be updated by comparing the instruction information received this time with the instruction information received last time. The bypass schedule of each of the strings St1 to Stx is a plan for bypassing the storage batteries B1 to Bm by the bypass switch units BSU1 to BSUm, and is determined based on a predetermined criterion. The string controllers SC1 to SCx determine whether or not switching from charging to discharging or from discharging to charging is performed in each of the strings St1 to Stx, and if the switching is performed, determine that the bypass schedule needs to be updated. If the bypass schedule needs to be updated, the string controllers SC1 to SCx determine the bypass schedule of the storage batteries B1 to Bm based on the module state information received from the module controllers MC1 to MCm and the estimated state of each of the storage batteries B1 to Bm.

[0055] On the other hand, the string controllers SC1-SCx determine whether or not control of the string charge / discharge power is necessary by comparing the current and previous module state information received from the module controllers MC1-MCm and the state estimation results of each of the storage batteries B1-Bm. If control of the string charge / discharge power is necessary, the string controllers SC1-SCx control the power converters PCS1-PCSx.

[0056] The string controllers SC1 to SCx control the power converters PCS1 to PCSx in accordance with the string charge / discharge power instruction value received from the string system controller SSC.

[0057] When the string controllers SC1 to SCx receive a maintenance / stop command from the string system controller SSC, they analyze the received maintenance / stop command and determine the type of maintenance to be performed. The types of maintenance include individual control, self-diagnosis, and replacement of the storage batteries B1 to Bm (hereinafter, storage battery replacement).

[0058] The individual control may include control for individually turning on / off the string cutoff switch 11 and the cooling devices in the strings St1 to Stx. The self-diagnosis may include abnormality determination for determining abnormalities that are difficult to determine during operation in the state estimation mode or the charge / discharge mode. The abnormality determination may include performing special control on the string auxiliaries 5 such as the power converters PCS1 to PCSx and the bypass switch units BSU1 to BSUm, acquiring the responses thereof using various sensors, and determining the presence or absence of an abnormality. The battery replacement may include providing guidance for replacing the batteries B1 to Bm that have deteriorated or have failed. When replacing the batteries, a work guide is displayed on the display / input device of the power storage system controller PSC, and the power storage system 1 executes necessary control such as stopping the strings St1 to Stx that are the targets of battery replacement. The strings St1 to Stx that are not the targets of battery replacement may be operated in the charge / discharge mode. After the battery replacement is completed, the strings St1 to Stx that have had their batteries replaced are operated in a state estimation mode, and module state information is transmitted from the module controllers MC1 to MCm to the string controllers SC1 to SCx. Note that the strings St1 to Stx that are not the targets of the battery replacement may be operated in a charge / discharge mode.

[0059] When the string controllers SC1 to SCx receive a state estimation instruction from the string system controller SSC, they compare the currently received string charge / discharge power instruction value with the previously received string charge / discharge power instruction value and determine whether there has been a change. When there is a change in the string charge / discharge power instruction value between the previous time and the current time, the string controllers SC1 to SCx control the string auxiliary device 5 and the bypass switch units BSU1 to BSUm in a predetermined manner so that state estimation of the strings St1 to Stx is possible. An example of a method for controlling the string auxiliary device 5 when the state estimation mode is executed is to turn on the string cutoff switch 11 and perform constant current control of the power converters PCS1 to PCSx. Also, an example of a method for controlling the bypass switch units BSU1 to BSUm when the state estimation mode is executed is to sequentially bypass the storage batteries B1 to Bm that have become fully discharged during discharging.

[0060] The string controllers SC1 to SCx record the module state information received from the module controllers MC1 to MCm. Furthermore, the string controllers SC1 to SCx update parameters used in state estimation as necessary based on the module state information received from the module controllers MC1 to MCm. These parameters include the SOH of the storage batteries B1 to Bm, a map of charge / discharge limit values ​​of the storage batteries B1 to Bm, SOC-OCV characteristics, etc.

[0061] The module controllers MC1 to MCm communicate with the string controllers SC1 to SCx to control and manage the module auxiliaries (not shown). The module auxiliaries include bypass switch units BSU1 to BSUm and various sensors. The various sensors include a voltage sensor that detects the voltage of the storage batteries B1 to Bm, a current sensor that detects the current of the storage batteries B1 to Bm, a temperature sensor that detects the temperature of the storage batteries B1 to Bm, and a cell voltage sensor that detects the cell voltage.

[0062] The module controllers MC1 to MCm receive status information of the storage batteries B1 to Bm from cell monitoring units (not shown) and the like. Examples of the status of the storage batteries B1 to Bm include the total voltage of the storage batteries B1 to Bm, the temperature of the storage batteries B1 to Bm, and the cell voltage. The cell monitoring units receive detection signals from various sensors, such as a module voltage sensor that detects the module voltage, a cell voltage sensor that detects the cell voltage, and a module temperature sensor that detects the module temperature. The cell monitoring units may be configured as standalone units, or may be configured by utilizing a battery cell monitoring IC (Integrated Circuit) in the module controllers MC1 to MCm.

[0063] The module controllers MC1-MCm receive state information of the batteries B1-Bm from the above-mentioned cell monitoring units or various sensors of the batteries B1-Bm, and estimate the states of the batteries B1-Bm based on the received information. Examples of the estimated states of the batteries B1-Bm include the SOC, SOH, and charge / discharge power limit values ​​of the batteries B1-Bm. The states of the batteries B1-Bm may be estimated by the string controllers SC1-SCx.

[0064] For example, when detected values ​​of the voltage sensors, cell voltage sensors, and module temperature sensors or estimated values ​​of the states of the storage batteries B1-Bm are outside the threshold range, the module controllers MC1-MCm determine whether or not there is an abnormality in the storage batteries B1-Bm. Then, the module controllers MC1-MCm shut off the storage batteries B1-Bm determined to have an abnormality with the bypass switch units BSU1-BSUm, or transmit an abnormality notification to the string controllers SC1-SCx. An abnormality in the storage batteries B1-Bm corresponds to an event.

[0065] The module controllers MC1 to MCm transmit to the string controllers SC1 to SCx information required for processing by higher-level controllers such as the string controllers SC1 to SCx, among information received from the cell monitoring units or various sensors and information estimated by themselves. Information required for processing by the string controllers SC1 to SCx includes the temperature, current, voltage, SOC, SOH, charge / discharge power limit value, cell voltage, and state of the bypass switch units BSU1 to BSUm of the storage batteries B1 to Bm.

[0066] Here, the string controllers SC1-SCx determine instructions corresponding to the respective batteries B1-Bm based on "information required for processing by the string controllers SC1-SCx" received from the module controllers MC1-MCm, and transmit the instruction information to the module controllers MC1-MCm. The instructions include bypass control of the batteries B1-Bm by the bypass switch units BSU1-BSUm, cut-off control of the batteries B1-Bm by the bypass switch units BSU1-BSUm, etc.

[0067] If there is a change between the current and previous instruction information received from the string controllers SC1-SCx, the module controllers MC1-MCm control the bypass switch units BSU1-BSUm to execute the above-mentioned bypass control or shutoff control. If there is a change in the information received from the cell monitoring units or various sensors and the information estimated by the module controllers MC1-MCm, the module controllers MC1-MCm execute exceptional control as necessary that is not based on an instruction from a higher-level controller. The module controllers MC1-MCm also transmit an instruction to the cell monitoring units to execute cell balancing for the storage batteries B1-Bm.

[0068] Fig. 3 is a flowchart for explaining the processing of the string system controller SSC shown in Fig. 1 and Fig. 2. When the power storage system 1 is operated, the processing of step S1 is started, and while the power storage system 1 is operating, the processing of steps S2 to S16 is repeated.

[0069] In step S1, the string system controller SSC initializes various parameters. Next, in step S2, the string system controller SSC receives string state information from each of the string controllers SC1 to SCx.

[0070] Next, in step S3, the string system controller SSC receives string system accessory status information (string bus voltage, string bus current, etc.) from the string system accessory 4.

[0071] Next, in step S4, the string system controller SSC estimates the state of the string system 10 based on the string state information received in step S2 and the string system accessory state information received in step S3. Note that the estimation of the state of the string system 10 may be performed by the power storage system controller PSC, and the estimation result may be transmitted from the power storage system controller PSC to the string system controller SSC or the upper server 7.

[0072] Next, in step S5, the string system controller SSC analyzes the information received or estimated in steps S2 to S4 and determines whether or not there is an abnormality in the string system 10. The string system controller SSC determines whether or not there is an abnormality in the string system 10, for example, by comparing various detection values ​​or estimated values ​​received or estimated in steps S2 to S4 with threshold values.

[0073] Next, in step S6, the string system controller SSC transmits information (string system state information) required for processing by the power storage system controller PSC and the upper server 7, among the information received, estimated, or determined in steps S2 to S5, to the power storage system controller PSC. Next, in step S7, the string system controller SSC receives an instruction transmitted from the power storage system controller PSC. Here, the power storage system controller PSC determines an instruction corresponding to the string system 10 (such as a power storage system charge / discharge power instruction value in a charge / discharge mode) based on the information received from the string system controller SSC in step S6, and transmits it to the string system controller SSC in step S7.

[0074] Next, in step S8, the string system controller SSC compares the current instruction with the previous instruction received from the power storage system controller PSC, and determines whether or not the operating states of the strings St1 to Stx need to be updated. For example, if there is a change between the previous and current storage system charge / discharge power instruction value received from the power storage system controller PSC, the string system controller SSC determines that the operating states of the strings St1 to Stx need to be updated. Also, for example, if there is a change between the previous and current individual control instruction in the maintenance mode received from the power storage system controller PSC, the string system controller SSC determines that the operating states of the strings St1 to Stx need to be updated. If a positive determination is made in step S8, the process proceeds to step S9, and if a negative determination is made in step S8, the process proceeds to step S2.

[0075] Next, in step S9, the string system controller SSC determines instructions for each of the string controllers SC1 to SCx in accordance with a predetermined condition. The predetermined conditions include the state of each of the strings St1 to Stx acquired in step S2, the operation history of each of the strings St1 to Stx from the past to the present, and various instructions inputted through the display input device. Items of instructions for each of the string controllers SC1 to SCx include the operation mode of each of the strings St1 to Stx (state estimation mode, charge / discharge mode, maintenance / stop mode, etc.), permission / non-permission of a bypass request from each of the string controllers SC1 to SCx, and allocation of string charge / discharge power instruction values ​​to each of the strings St1 to Stx. When a maintenance / stop instruction is inputted through the display input device, the string system controller SSC determines the instruction for each of the strings St1 to Stx to be a maintenance / stop instruction. Similarly, when an instruction to forcibly execute charging / discharging or state estimation is input via the display / input device of the power storage system controller PSC, the string system controller SSC determines the instruction for each of the strings St1 to Stx to be a charging / discharging instruction or a state estimation instruction.

[0076] Next, in step S10, the string system controller SSC sets a count value m for managing the transmission of instruction information to the string controllers SC1 to SCx to an initial value (m=1). Next, in step S11, the string system controller SSC determines whether the operation mode of the strings St1 to Stx to which the instruction is applied is a charge / discharge mode, a state estimation mode, or a maintenance / stop mode. If it is the charge / discharge mode, the process proceeds to step S13; if it is the state estimation mode, the process proceeds to step S12; and if it is the maintenance / stop mode, the process proceeds to step S14.

[0077] In step S12, the string system controller SSC transmits a state estimation instruction to the target string controllers SC1 to SCx. Items of the state estimation instruction include ON of a state estimation mode flag, a string charge / discharge power instruction value, bypass permission / non-permission, etc. In the state estimation mode of each of the strings St1 to Stx, for example, discharge is performed at a constant current, and data such as voltage is acquired during the discharge. Here, if there is variation in the deterioration degree of the storage batteries B1 to Bm in each of the strings St1 to Stx, the storage batteries B1 to Bm are fully discharged in order from the most deteriorated one. Then, each time the storage batteries B1 to Bm are fully discharged, a bypass request is transmitted from the module controllers MC1 to MCm. As a result, the string system controller SSC determines whether or not to notify bypass permission in response to the received bypass request, and transmits a notification of bypass permission / non-permission to the string controllers SC1 to SCx.

[0078] On the other hand, in step S13, the string system controller SSC transmits a charge / discharge instruction to the target string controllers SC1 to SCx. Items of the charge / discharge instruction include ON of the charge / discharge mode flag, a string charge / discharge power instruction value, bypass permission / non-permission, etc. If there is a fully discharged or fully charged storage battery B1 to Bm, a bypass request is transmitted from the module controllers MC1 to MCm. In response to the received bypass request, the string system controller SSC determines whether or not to notify bypass permission, and transmits a notification of bypass permission / non-permission to the string controllers SC1 to SCx.

[0079] On the other hand, in step S14, the string system controller SSC transmits a maintenance / stop instruction to the target string controllers SC1 to SCx. Items of the maintenance / stop instruction include ON of the maintenance / stop flag, various instructions, bypass permission / non-permission, etc. The various instructions are instructions corresponding to instructions inputted through the display input device. For example, an instruction to forcibly operate the power storage system auxiliary 3, the string system auxiliary 4, the string auxiliary 5, and the bypass switch units BSU1 to BSUm is included. Here, when an instruction to forcibly operate the bypass switch units BSU1 to BSUm is inputted through the display input device, the string system controller SSC transmits an instruction to permit / non-permit bypass to the string controllers SC1 to SCx. Note that the maintenance / stop instruction is not limited to being inputted through the display input device, but may be transmitted when an abnormality occurs or periodically.

[0080] The process proceeds from steps S12, S13, and S14 to step S15, where the string system controller SSC adds 1 to a count value m for managing the transmission of instruction information to the string controllers SC1 to SCx. Next, in step S16, the string system controller SSC determines whether or not the transmission of instructions to all of the string controllers SC1 to SCx has been completed. Specifically, the string system controller SSC determines whether or not the count value m has reached the total number x of the string controllers SC1 to SCx. If a negative determination is made in step S16, the process proceeds to step S11, and steps S11 to S16 are repeated. On the other hand, if a positive determination is made in step S16, the process proceeds to step S2, and the processing of steps S2 to S16 is repeated while the power storage system 1 is in operation.

[0081] A communication method of the power storage system 1 of this embodiment will be described below. A large number of strings St1 to Stx (for example, 50 to 100 strings) are connected to the power storage system 1 shown in Fig. 1 and Fig. 2, and a large number of modules M1 to Mm (for example, 10 to 50) are connected to each of the strings St1 to Stx. Therefore, the amount of information communicated between the controllers of the power storage system 1 is enormous.

[0082] Each of the string controllers SC1 to SCx transmits information on the state of each of the strings St1 to Stx (the above-mentioned string state information) to the string system controller SSC. In addition, the string system controller SSC transmits various kinds of instruction information to each of the string controllers SC1 to SCx.

[0083] Here, the string status information and instruction information communicated between the string system controller SSC and the multiple string controllers SC1 to SCx are divided into information that requires periodic communication (hereinafter, base information) and information that is communicated when an event occurs (hereinafter, event information). Examples of events include input of various instruction information by an operator or the like to a display input device of the power storage system controller PSC, occurrence of an abnormality in the power storage system 1, etc.

[0084] Examples of the string state information include a charge / discharge power upper limit, a discharge power upper limit, a string SOC, a string SOH, a control request for the bypass switch units BSU1-BSUm, the voltages and cell voltages of the storage batteries B1-Bm, etc. Here, examples of base information included in the string state information include a charge power upper limit, a discharge power upper limit, a string SOC, a string SOH, a bypass control request, etc. In contrast, examples of event information included in the string state information include information such as the voltages and cell voltages of the storage batteries B1-Bm that are transmitted only upon request from the string system controller SSC, various types of error information, etc.

[0085] Examples of the instruction information include permission to control the bypass switch units BSU1 to BSUm, an instruction for an operation mode, a charge / discharge status, a charge / discharge power instruction value, an instruction to update the control of the power converters PCS1 to PCSx, various request information, individual control instructions, etc. Here, examples of base information included in the instruction information include the bypass switch units BSU1 to BSUm, an instruction for an operation mode, a charge / discharge status, a charge / discharge power instruction value, an instruction to update the control of the power converters PCS1 to PCSx, etc. Meanwhile, examples of event information included in the instruction information include various request information, individual control instructions, etc. Examples of the various request information include information instructing the acquisition of string state information such as the voltages and cell voltages of the storage batteries B1 to Bm in response to a request from an operator, etc.

[0086] Here, the processing of each controller according to the base information requires a high response of tens to hundreds of msec, whereas the processing of each controller according to the event information allows a response of about several seconds. For example, the processing of each controller according to the event information includes a process in which an operator or the like inputs an instruction to a display input device requesting acquisition of string status information, and the string status information is transmitted from a lower controller to a higher controller in response to the instruction. Through this processing, the status information of the power storage system 1, the status information of each of the strings St1 to Stx, the status information of each of the modules M1 to Mm, etc. are displayed on the display input device.

[0087] Moreover, examples of string status information that is the subject of an acquisition request include cell voltages. The cell voltages are not transmitted from the lowest-order module controllers MC1 to MCm to higher-order controllers in a process according to the base information. Therefore, when an event occurs that requests the acquisition of a cell voltage, the cell voltages must be transmitted in this order from the module controllers MC1 to MCm to the string controllers SC1 to SCx, the string system controller SSC, and the power storage system controller PSC. At this time, a response time of about several seconds is allowed from the input of an instruction by an operator or the like to a display / input device of the power storage system controller PSC to the output of information to the display / input device.

[0088] Furthermore, the processing of each controller in response to the event information includes a process in which, when an abnormality occurs, abnormality occurrence information and processing details at the time of the abnormality are transmitted from a lower controller to a higher controller. When an abnormality occurs, the string controllers SC1 to SCx quickly control the power converters PCS1 to PCSx to reduce the charging / discharging power and cut off the string bus 6. When an abnormality occurs, the module controllers MC1 to MCm quickly control the bypass switch units BSU1 to BSUm to open each switch S2. In contrast, there is no problem if the response time from the time of abnormality occurrence until the abnormality occurrence information and processing details at the time of the abnormality are transmitted from the module controllers MC1 to MCm to the power storage system controller PSC is several seconds.

[0089] In this embodiment, in CAN communication between controllers, a data frame including base information and event information is transmitted. This data frame is transmitted at a period of several tens of milliseconds in accordance with the response requirement of the processing according to the base information.

[0090] Here, since the power storage system 1 of the present embodiment is a large-scale system including many strings St1-Stx and many modules M1-Mm, the types of event information are huge, for example, several hundred types or more. Therefore, if a data frame including all types of event information is configured, the data frame will have a large capacity, and the frame length of the data frame will change depending on the amount of information when an event occurs.

[0091] Therefore, in the power storage system 1 of this embodiment, a data frame transmitted at a period of several tens of msec is configured to include base information of a predetermined data length (e.g., 48 bits) and event information of a predetermined data length (e.g., 16 bits) shorter than the data length of the base information. The event information is then transmitted over a maximum period of several seconds by using multiple data frame communications.

[0092] Fig. 4 is a diagram showing the structure of a data frame transmitted in CAN communication between the string system controller SSC and the multiple string controllers SC1 to SCx of the battery control device 2 shown in Fig. 1 and Fig. 2. This diagram shows the frame structure of the standard format of CAN communication. The configuration other than the data field is the same as the standard format of general CAN communication, so a description thereof will be omitted.

[0093] In the energy storage system 1 of this embodiment, a 64-bit data field is divided into a 48-bit base data field BDF (registered trademark) and a 16-bit event data field IDF. The base data field BDF is assigned with the contents and data of the base information. In contrast, the event data field IDF is assigned with the contents (8 bits) and data (8 bits) of the event information. The contents of the event information are identified by an ID, which is predetermined, for example, as shown in Table 1 below. The order of transmission of the event information follows a predetermined priority order, such as the order of the ID numbers. [Table 1]

[0094] The capacity of the event data field IDF is 16 bits in total, consisting of 8 bits of the content of the event information and 8 bits of data, so for example, the voltages of cells 1 of ID51 and ID52 are transmitted in two separate data frame communications. Therefore, dozens of data frames are transmitted in order to display the cell voltages of all the cells in one storage battery B1 to Bm on the display input device of the power storage system controller PSC.

[0095] As described above, the storage battery control device 2 according to this embodiment includes a plurality of string controllers SC1-SCx provided for the strings St1-Stx, and a string system controller SSC. Each of the string controllers SC1-SCx controls the corresponding string St1-Stx. The string system controller SSC transmits and receives data frames to and from the plurality of string controllers SC1-SCx at a predetermined cycle.

[0096] Here, the data frame includes a base data field BDF to which base information transmitted and received at the predetermined cycle is assigned, and an event data field IDF to which event information transmitted and received when an event occurs is assigned. The base data field BDF is assigned the same type of base information at the predetermined cycle, and the event data field IDF has a smaller capacity than the base data field BDF and is assigned different types of event information at the predetermined cycle.

[0097] This makes it possible to suppress an increase in the capacity of the data field, to keep the data length of the data field constant for each transmission cycle, and to transmit and receive information used in processes that require high responsiveness in a desired cycle. Also, information used in processes that require high tolerance for responsiveness can be transmitted and received within an allowed response time that is longer than the predetermined cycle. Therefore, the requirement for responsiveness to instructions from the power storage system controller PSC can be met.

[0098] Furthermore, in the battery control device 2 of this embodiment, when the volume of event information exceeds the volume of the event data field IDF, the event information is transmitted and received between the string system controller SSC and the multiple string controllers SC1 to SCx during a plurality of the predetermined periods. That is, a large volume of event information exceeding the volume of the event data field IDF is transmitted and received between the string system controller SSC and the multiple string controllers SC1 to SCx by transmitting and receiving data frames multiple times. This makes it possible to process a large volume of event information without increasing the communication speed or making the communication line multiple lines.

[0099] Furthermore, in the battery control device 2 of this embodiment, when the volume of event information exceeds the volume of the event data field IDF, the event information is transmitted and received between the string system controller SSC and the multiple string controllers SC1 to SCx in accordance with a predetermined priority order during a plurality of the above-mentioned predetermined cycles. That is, a large volume of event information exceeding the volume of the event data field IDF is transmitted and received between the string system controller SSC and the multiple string controllers SC1 to SCx in a predetermined order by transmitting and receiving data frames multiple times. This allows the large volume of event information to be processed in an orderly manner.

[0100] Furthermore, in the battery control device 2 of this embodiment, instruction information for instructing control of the strings St1 to Stx is assigned to a data field of a data frame transmitted by the string system controller SSC to the multiple string controllers SC1 to SCx. The instruction information is divided into base information and event information, which are assigned to a base data field BDF and an event data field IDF, respectively. This allows instruction information used in control requiring high responsiveness to be transmitted at a desired period. Furthermore, instruction information used in control requiring high tolerance for responsiveness to be transmitted within an allowed response time that is longer than the above-mentioned predetermined period.

[0101] Furthermore, in the battery control device 2 of this embodiment, string status information is assigned to a data field of a data frame transmitted from the multiple string controllers SC1 to SCx to the string system controller SSC. The string status information is divided into base information and event information, which are assigned to a base data field BDF and an event data field IDF, respectively. This allows the string status information used in a process requiring high responsiveness to be transmitted at a desired period. Furthermore, the string status information used in a process requiring high tolerance for responsiveness to be transmitted within an allowed response time that is longer than the predetermined period.

[0102] The present invention has been described above based on the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment, and modifications may be made without departing from the spirit of the present invention, and publicly known or well-known technologies may be combined as appropriate.

[0103] For example, in the above-described embodiment, data frames are transmitted and received between the string system controller SSC and the string controllers SC1 to SCx. However, the power storage system controller PSC and the string system controller SSC may be integrated, and data frames may be transmitted and received between the integrated controller and the string controllers SC1 to SCx. Also, one of the multiple string controllers SC1 to SCx may be a master controller and the others may be slave controllers, and data frames may be transmitted and received between the master controller and the slave controller.

[0104] In the above embodiment, the data frame transmitted between the string system controller SSC and the string controllers SC1 to SCx is in the standard format of CAN communication, but it may be in an extended format of CAN communication. Also, other communication standards may be adopted to make the data frame conforming to the communication standards. Furthermore, the data lengths of the base data field BDF and the event data field IDF may be set appropriately. [Explanation of symbols]

[0105] 1: Energy storage system 2: Battery control device BDF: Base Data Field (first data area) IDF: Event data field (second data area) SC1: String controller (first control section) SCx: String controller (first control section) SSC: String System Controller (Second control section) St1: String (energy storage string) Stx: String (energy storage string)

Claims

1. A battery control device for controlling a battery storage system including a plurality of battery storage strings connected in parallel, A plurality of first control units provided for each of the power storage strings and controlling the corresponding power storage strings; a second control unit that transmits and receives data frames to and from the plurality of first control units at a predetermined period; Equipped with the data frame includes a first data area to which first information transmitted and received at the predetermined period is assigned, and a second data area to which second information transmitted and received when an event occurs is assigned, The first data area is allocated with the same type of first information at each predetermined period, The second data area has a smaller capacity than the first data area, and different types of second information are assigned to the second data area for each predetermined period.

2. The battery control device according to claim 1, wherein when the capacity of the second information exceeds the capacity of the second data area, the second information is transmitted and received between a plurality of the first control units and the second control unit during a plurality of periods of the specified cycle.

3. The battery control device according to claim 2 , wherein the second information is transmitted and received between a plurality of the first control units and the second control unit during the plurality of cycles in accordance with a predetermined priority order.

4. The data frame transmitted by the second control unit to the first control units is assigned with instruction information for instructing control of the power storage string, The battery control device according to claim 1 , wherein the instruction information is divided into the first information and the second information.

5. The data frames transmitted from the plurality of first control units to the second control unit are assigned with status information indicating a status of the power storage string, The battery control device according to claim 1 , wherein the state information is divided into the first information and the second information.

6. A plurality of storage strings connected in parallel; A battery control device that controls the plurality of battery strings; A power storage system comprising: The battery control device includes: A plurality of first control units provided for each of the power storage strings and controlling the corresponding power storage strings; a second control unit that transmits and receives data frames to and from the plurality of first control units at a predetermined period; Equipped with the data frame includes a first data area to which first information transmitted and received at the predetermined period is assigned, and a second data area to which second information transmitted and received when an event occurs is assigned, The first data area is allocated with the same type of first information at each predetermined period, The second data area has a smaller capacity than the first data area, and different types of the second information are assigned to the second data area for each predetermined period.

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