Battery control device and power storage system

Abstract

To enable a string control unit to identify the placement of storage battery modules within a string after the communication IDs of a plurality of module control units are automatically set.SOLUTION: A string controller SC assigns communication IDs to module controllers MC1 to MCm, and then executes a placement identification process. The placement identification process includes a transmission process for transmitting, to one of the module controllers MC1 to MCm, a control signal to connect switches S31 to S3m, an acquisition process for acquiring a measurement value of a voltage sensor 12 in a state where the switches S31 to S3m are connected, and an identification process for identifying the placement in a string St of storage battery modules M1 to Mm corresponding to the module controllers MC1 to MCm based on the acquired measurement value of the voltage sensor 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As an in-vehicle data communication system in which a master device and multiple slave devices are connected to the same communication bus, one that automatically sets the communication address of the slave device when the network is started is known (see, for example, Patent Document 1). In the in-vehicle data communication system described in Patent Document 1, when connection request information is sent from a slave device to the master device when the network is started, the master device sets the communication address of the slave device to be different from that of the other slave devices and notifies the slave device of the set address. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-326896 Summary of the Invention [Problem to be solved by the invention]

[0004] In a power storage system having a string in which multiple storage battery modules are connected in series, a method for setting the communication IDs of multiple module control units is considered in order to perform communication between a string control unit (master device) corresponding to the string and multiple module control units (slave devices) corresponding to the storage battery modules, respectively. Such methods include a method in which the user manually sets the IDs, and a method in which the string control unit, which is the master device, automatically sets the IDs, as described in Patent Document 1.

[0005] In the method of manually setting the communication ID, a switch for setting the communication ID is installed in the module control unit, and the user sets the switch for each module control unit. With this method, if the user makes a mistake in setting the switch, there is a risk that all communication in the energy storage system will be disabled.

[0006] In the method in which the string control unit automatically sets the communication ID, the string control unit broadcasts the communication ID to multiple module control units, and each module control unit responds in turn, repeating an automatic allocation process. This method does not associate the module control unit assigned the communication ID with the arrangement (order) of the storage battery module corresponding to that module control unit within the string. Therefore, for example, when a module control unit notifies the string control unit of an abnormality in a storage module, the string control unit cannot identify the arrangement within the string of the storage battery module corresponding to the module control unit that notified the abnormality.

[0007] In view of the above circumstances, the present invention aims to provide a battery control device and a battery system in a battery system having a string in which multiple battery modules are connected in series, which automatically sets the communication IDs of multiple module control units and enables the string control unit to identify the arrangement of the battery modules within the string. [Means for solving the problem]

[0008] The battery control device of the present invention is a battery control device for controlling a power storage system including a string in which a plurality of battery modules are connected in series, and includes a plurality of module control units provided corresponding to the battery modules, a string control unit provided corresponding to the string and setting a communication ID for the plurality of module control units to communicate with the plurality of module control units, a signal line connecting the negative electrode side of the battery module that is most negatively disposed among the plurality of battery modules to the positive electrode side of each of the plurality of battery modules, a voltage sensor provided on the signal line, and a signal transmitted by the module control unit provided corresponding to the battery modules. and a plurality of switches that connect or disconnect the positive electrode side of the storage battery module to the signal line in response to a control signal received from the module control unit, and after setting the communication ID in the module control unit, the string control unit executes a placement identification process for identifying the placement of the storage battery module corresponding to the module control unit within the string, the placement identification process including a transmission process for transmitting a control signal to one of the plurality of module control units to put the switch into a connected state, an acquisition process for acquiring a measurement value of the voltage sensor when the switch is put into the connected state, and an identification process for identifying the placement of the storage battery module corresponding to the module control unit within the string in response to the acquired measurement value.

[0009] The power storage system of the present invention is a power storage system including a string in which a plurality of storage battery modules are connected in series, and includes the storage battery control device according to any one of claims 1 to 3. [Effects of the Invention]

[0010] According to the present invention, in a power storage system having a string in which multiple storage battery modules are connected in series, the communication IDs of multiple module control units are automatically set, and the string control unit can identify the arrangement of the storage battery modules within the string. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a circuit diagram showing the circuit configuration of a power storage system including a battery control device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a control configuration of the power storage system shown in FIG. [Figure 3] FIG. 3 is a flowchart illustrating the arrangement identification process executed by the battery control device shown in FIGS. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below in accordance with preferred embodiments. Note that the present invention is not limited to the embodiments described below, and the embodiments can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiments described below, some components are omitted from illustration and description, but for the details of the omitted technologies, publicly known or well-known technologies are applied as appropriate within the scope of not causing any contradictions with the content described below.

[0013] 1 is a circuit diagram showing the circuit configuration of a power storage system 1 including a battery control device 2 according to one embodiment of the present invention. The power storage system 1 shown in this diagram is a stationary power source and includes a string system 10 and a power storage system controller PSC.

[0014] The power storage system controller PSC is the highest-level control device in the power storage system 1, and communicates with the host server 7 (see FIG. 2) and the string system controller SSC to control the power storage system accessories 3 (see FIG. 2). The power storage system controller PSC also includes a display / input device (not shown) such as a touch panel that has a display function and an input function.

[0015] The string system 10 includes a plurality of strings St1 to Stx, a plurality of power converters PCS1 to PCSx, 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. When it is not necessary to distinguish between the strings St1 to Stx, the strings St1 to Stx will be referred to as strings St. When it is not necessary to distinguish between the power converters PCS1 to PCSx, the power converters PCS1 to PCSx will be referred to as power converters PCS. When it is not necessary to distinguish between the string controllers SC1 to SCx, the string controllers SC1 to SCx will be referred to as string controllers SC.

[0016] The strings St are connected in parallel to a string bus 6 via a power converter PCS. The string bus 6 is connected to an external system (not shown). The string St includes a plurality of storage battery modules M1 to Mm connected in series. Each storage battery module M1 to Mm is provided with module controllers MC1 to MCm, bypass mechanisms B1 to Bm, switches S31 to S3m, and a cell monitoring unit (not shown). When it is not necessary to distinguish between the storage battery modules M1 to Mm, the storage battery modules M1 to Mm will be referred to as a storage battery module M. When it is not necessary to distinguish between the bypass mechanisms B1 to Bm, the bypass mechanisms B1 to Bm will be referred to as a bypass mechanism B. When it is not necessary to distinguish between the module controllers MC1 to MCm, the module controllers MC1 to MCm will be referred to as a module controller MC. When it is not necessary to distinguish between the switches S31 to S3m, the switches S31 to S3m will be referred to as a switch S3.

[0017] The storage battery module M includes a plurality of storage battery cells C connected in series. The storage battery cells C are secondary battery cells such as lithium ion batteries or lithium ion capacitors, and are charged by receiving power from an external system via a power converter PCS. The charged power is then discharged via the power converter PCS to supply power to the external system. Although not particularly limited, the storage battery modules M of this embodiment are refurbished secondhand storage battery modules, and there are differences in the degree of deterioration. Note that storage battery cells or storage battery packs may be provided instead of the storage battery modules M.

[0018] The m (an integer of 2 or more) storage battery modules M1 to Mm are arranged in order from the positive electrode side to the negative electrode side of the string St, starting with the module with the smallest sign. That is, the storage battery module M1 is arranged on the most positive electrode side of the string St, the storage battery module M2 is arranged on the negative electrode side of the string St from the storage battery module M1, and the storage battery module Mm is arranged on the most negative electrode side of the string St. Note that the storage battery module M1 on the most positive electrode side of the string St may be referred to as the starting storage battery module M1, and the storage battery module Mm on the most negative electrode side of the string St may be referred to as the terminal storage battery module Mm.

[0019] The bypass mechanism B includes a bypass line BL, a switch S1, and a switch S2. The bypass line BL is a power line that bypasses the storage battery module M. 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 the storage battery module M and one end of the bypass line BL. The switch S2 is, for example, a mechanical switch, a semiconductor switch, or a relay.

[0020] The starting battery module M1 and the ending battery module Mm are connected to an external system via a power converter PCS and a string bus 6. When the switch S1 is turned OFF and the switch S2 is turned ON in all bypass mechanisms B, all the battery modules M of the string St are connected in series to the external system. When the switch S1 is turned OFF and the switch S2 is turned ON in the bypass mechanism B, the bypass of the battery modules M is released (hereinafter referred to as the bypass released state).

[0021] On the other hand, when the switch S2 is turned OFF and the switch S1 is turned ON in any of the bypass mechanisms B, the storage battery module M corresponding to that bypass mechanism B is bypassed. When the switch S1 is ON and the switch S2 is OFF in the bypass mechanism B, the storage battery module M is bypassed (hereinafter referred to as the bypass state).

[0022] The power converter PCS is a bidirectional converter and is connected to the string bus 6. The power converter PCS is also connected to the positive electrode side of the starting storage battery module M1 and the negative electrode side of the terminal storage battery module Mm.

[0023] When charging the strings St, the power converter PCS converts the voltage input from the string bus 6 and transmits it to the multiple storage battery modules M. Here, the voltage on the string St side changes depending on the bypass state of the multiple storage battery modules M (the number of storage battery modules M that are bypassed) and the charging state of the multiple storage battery modules M. Therefore, when charging the strings St, the power converter PCS converts the voltage input from the string bus 6 to the voltage on the string St side and transmits it to the multiple storage battery modules M.

[0024] When a string St is discharged, the power converter PCS converts the voltage input from the multiple storage battery modules M and transmits it to the string bus 6. Here, the input voltage of the power converter PCS during discharge varies depending on the bypass state of the multiple storage battery modules M and the charge state of the multiple storage battery modules M. This causes variations in the input voltage of the power converter PCS between strings St during discharge. Therefore, when a string St is discharged, the power converter PCS converts the input voltage to a voltage that matches the other strings St and transmits it to the string bus 6. Note that when the current flowing through the string bus 6 is AC, the power converter PCS is equipped with synchronization means for tracking changes in instantaneous values.

[0025] The cell monitoring unit is connected between the positive and negative terminals of each storage battery cell C, detects the terminal voltage (hereinafter referred to as cell voltage) of each storage battery cell C, and sends a detection signal to the module controller MC. The cell monitoring unit also has a cell balancing function and equalizes the cell voltages of the storage battery module M.

[0026] The module controller MC has a function of communicating with the string controller SC, a function of controlling the switches S1 and S2 of the bypass mechanism B, and a function of controlling the switch S3. The string controller SC sets communication IDs to the multiple module controllers MC in order to communicate with the multiple module controllers MC. The module controller MC controls the switches S1, S2, and S3 in response to control signals transmitted from the string controller SC.

[0027] The string St is provided with a current sensor 11, a voltage sensor 12, and a placement identification circuit 13. The current sensor 11 is provided between the power converter PCS and the positive electrode side of the starting storage battery module M1, and measures the total current of the string St and transmits the measurement value to the string controller SC. The placement of the current sensor 11 is not particularly limited, and may be provided, for example, between the negative electrode side of the terminal storage battery module Mm and the power converter PCS.

[0028] The placement identification circuit 13 is a circuit for identifying the placement within the string St of the storage battery module M corresponding to the module controller MC to which the communication ID is set. This placement identification circuit 13 includes a plurality of switches S31 to S3m provided for each storage battery module M, and a signal line 131. The switch S31 is provided corresponding to the starting storage battery module M1 and is controlled by the module controller MC1. The switch S3m is provided corresponding to the terminal storage battery module Mm and is controlled by the module controller MCm.

[0029] The signal line 131 connects the negative electrode side of the terminal storage battery module Mm to the positive electrode sides of each of the multiple storage battery modules M1 to Mm. The signal line 131 is composed of a signal line 131A connected to the negative electrode side of the terminal storage battery module Mm, signal lines 1311 to 131m branching from the signal line 131A, and a part of the bypass line BL to which the signal lines 1311 to 131m are connected. The "part" of the bypass line BL is the part of the bypass line BL that connects the switch S1 in the bypass line BL to the positive electrode of the storage battery module M.

[0030] The voltage sensor 12 is provided on the signal line 131A and transmits the measured voltage value to the string controller SC. The switches S3 are provided on the signal lines 1311 to 131m and connect or disconnect the positive electrode side of the corresponding storage battery module M to the signal line 131 in response to a control signal from the corresponding module controller MC. The switches S3 are, for example, mechanical switches, semiconductor switches, or relays. The switches S3 are preferably, but not necessarily, normally open switches.

[0031] When any one of the switches S31 to S3m is turned ON, the positive electrode side of the storage battery module M corresponding to that switch S3 is connected to the negative electrode side of the terminal storage battery module Mm by a signal line 131. In this state, when all the bypass mechanisms B are in the bypass release state, the voltage measured by the voltage sensor 12 is the sum of the voltages of the storage battery modules M located between both ends of the signal line 131.

[0032] For example, when switch S32 is ON and the other switches S3 are OFF, the positive electrode side of storage battery module M2 is connected to the negative electrode side of the terminal storage battery module Mm by signal line 131. When all bypass mechanisms B are in the bypass-released state in this state, the voltage measured by voltage sensor 12 is the sum of the voltages of storage battery modules M2 to Mm. When switch S31 is ON and the other switches S3 are OFF, the positive electrode side of storage battery module M1 is connected to the negative electrode side of the terminal storage battery module Mm by signal line 131. When all bypass mechanisms B are in the bypass-released state in this state, the voltage measured by voltage sensor 12 is the sum of the voltages of storage battery modules M1 to Mm (total voltage of string St). When switch S3m is ON and the other switches S3 are OFF, the positive electrode side and negative electrode side of storage battery module Mm are connected by signal line 131. In this state, the voltage measured by voltage sensor 12 is the voltage of storage battery module Mm.

[0033] Fig. 2 is a block diagram showing the 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 power storage system controller PSC, a string system controller SSC, a plurality of string controllers SC, and a plurality of module controllers MC.

[0034] The power storage system controller PSC, string system controller SSC, string controller SC, and module controller MC 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 controller SC corresponds to the hierarchical level of the string St, which is next to the hierarchical level of the string system 10. The module controller MC corresponds to the hierarchical level of the storage battery module M, which is next to the hierarchical level of the string St.

[0035] 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 installed in the aggregator's facility or in power receiving equipment in a building, factory, etc. This host server 7 calculates a charge / discharge power instruction value for the entire power storage system 1 (hereinafter referred to as the power storage system charge / discharge power instruction value) according to the state of the power storage system 1 and the power demand on the demand side, and transmits it to the power storage system controller PSC.

[0036] The power storage system accessories 3 include a temperature sensor that detects the temperature of the installation environment (for example, a container, etc.) of the power storage system 1, a fire extinguishing equipment, etc. (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 sends an abnormality notification to the display input device. The power storage system controller PSC also monitors the operating state of the fire extinguishing equipment.

[0037] The storage system controller PSC receives information about the state of the string St (hereinafter referred to as string state information) and information about the state of the string system 10 (hereinafter referred to as string system state information) from the string system controller SSC, and transmits them to the upper server 7 and the display input device.

[0038] The state of string St includes the operating state such as charging, discharging, resting, maintenance, etc., the string current, the total string voltage, the SOC (State of Charge) of string St (hereinafter referred to as string SOC), the SOH (State of Health) of string St (hereinafter referred to as string SOH), and the limit value of the charging / discharging power (or charging / discharging current) of string St (hereinafter referred to as string charging / discharging power limit value).

[0039] The state of the string system 10 may include the current of the string bus 6 (hereinafter referred to as the string bus current), the voltage of the string bus 6 (hereinafter referred to as the string bus voltage), the SOC of the string system 10 (hereinafter referred to as the string system SOC), the SOH of the string system 10 (hereinafter referred to as the string system SOH), and the limit value of the charge / discharge power (or charge / discharge current) of the string system 10 (hereinafter referred to as the string system charge / discharge power limit value).

[0040] The power storage system controller PSC estimates the state of the power storage system 1 based on the string state information and string system state information received from the string system controller SSC. The state of the power storage system 1 may include an operating state such as charging, discharging, suspension, maintenance, etc., the SOC of the power storage system 1 (hereinafter referred to as power storage system SOC), and the SOH of the power storage system 1 (hereinafter referred to as power storage system SOH). The power storage system controller PSC transmits information about the estimated state of the power storage system 1 to the display input device as needed. Note that in this embodiment where 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.

[0041] 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 instruction to the power storage system controller PSC. The charge / discharge instruction may include, in addition to the power storage system charge / discharge power instruction value, control variables such as a constant voltage (CV) mode, a constant current (CC) mode, and a constant power (CP) mode, an operation method such as independent operation / grid-connected operation, and the like.

[0042] The power storage system controller PSC transmits various instruction information input by the user via the display input device to the string system controller SSC. Examples of the instruction information that can be input via the display input device include an instruction to execute a maintenance / stop mode (hereinafter referred to as a maintenance / stop instruction), an instruction to forcibly execute charging / discharging, an instruction to forcibly execute state estimation, etc.

[0043] Examples of maintenance / stop instructions include instructions to forcibly operate the power storage system auxiliaries 3, the string system auxiliaries 4, and the string auxiliaries 5 such as the power converter PCS and the switches S1, S2, and S3. By forcibly operating the power storage system auxiliaries 3, the string system auxiliaries 4, and the string auxiliaries 5, it becomes possible to check the operation of the power storage system auxiliaries 3, the string system auxiliaries 4, and the string auxiliaries 5.

[0044] An example of an instruction to forcibly charge or discharge is an instruction to specify a predetermined charge or discharge amount and forcibly charge or discharge the power storage system 1. By specifying the predetermined charge or discharge amount and forcibly charging or discharging the power storage system 1, it becomes possible to check whether the power storage system 1 can charge or discharge the specified predetermined charge or discharge amount.

[0045] An example of an instruction to forcibly execute state estimation is an instruction to specify a predetermined item of state estimation and forcibly execute state estimation in the power storage system 1. By specifying a predetermined item of state estimation and forcibly executing state estimation in the power storage system 1, it becomes possible to acquire, for example, state estimation items such as the string system SOH and the power storage system SOH at any time.

[0046] The string system controller SSC communicates with the power storage system controller PSC and multiple string controllers SC, 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 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 not shown).

[0047] The string system controller SSC receives string status information from multiple string controllers SC. The status of the string St includes an operating state such as charging, discharging, resting, maintenance, etc., a string current, a string total voltage, a string SOC, a string SOH, a string charge / discharge power limit value, and a status of the string system auxiliary device 4. The status of the string system auxiliary device 4 includes a string bus current, a string bus voltage, etc.

[0048] The string system controller SSC estimates the state of the string system 10 based on string state information received from the multiple string controllers SC. Examples of the state of the string system 10 include the string bus current, the string bus voltage, the string system SOC, the string system SOH, and the string system charge / discharge power limit value. Note that the state of the string system 10 may be estimated by the power storage system controller PSC.

[0049] For example, if the detected values ​​of the temperature sensor, current sensor, or voltage sensor or the estimated value of the state of the string system 10 are outside the threshold range, the string system controller SSC determines that there is an abnormality in the string system 10 and stops operation of the string system 10 or sends an abnormality notification to the storage system controller PSC.

[0050] The string system controller SSC transmits to the power storage system controller PSC information required for the processing of the power storage system controller PSC from among the information received from the multiple string controllers SC and information estimated by itself. Examples of information required for the processing of the power storage system controller PSC include the string system SOC, the string system SOH, and the string system charge / discharge power limit value.

[0051] The power storage system controller PSC determines instructions corresponding to the string system 10 based on the "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. These instructions include charge / discharge instructions for the string system 10 in the charge / discharge mode, instructions to individually control each part of the string system 10 in the maintenance mode (hereinafter, individual control instructions), and state estimation instructions for the string system 10 in the state estimation mode. The charge / discharge instructions for the string system 10 in the charge / discharge mode include, in addition to charge / discharge power instruction values ​​assigned to each string system 10, 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-connected operation. The individual control instructions for the string system 10 in the maintenance mode include instructions to individually control the power converter PCS, the switches S1 and S2 of the bypass mechanism B, and the string system auxiliary device 4. The state estimation instructions for the string system 10 in the state estimation mode include instructions to execute predetermined control necessary to estimate the state of the string St.

[0052] The string system controller SSC receives an instruction corresponding to the above-mentioned string system 10 from the power storage system controller PSC, and compares the currently received instruction with the previously received instruction to determine whether or not the operating state of the string system 10 needs to be updated. If the operating state of the string system 10 needs to be updated, the string system controller SSC determines the operating mode of the string St, whether to grant permission to a bypass request from the string controller SC, and a string charge / discharge power instruction value to be assigned to the string St. Examples of the operating mode of the string St include a charge / discharge mode, a state estimation mode, and a maintenance / stop mode.

[0053] The string controller SC communicates with the string system controller SSC and multiple module controllers MC to control and manage the string auxiliaries 5. The string auxiliaries 5 include a power converter PCS, a current sensor 11 (see FIG. 1) that detects the string current, a voltage sensor (not shown) that detects the total string voltage, and switches S1, S2, S3.

[0054] The string controller SC receives information about the state of the storage battery module M (hereinafter referred to as module state information) from the module controller MC. The state of the storage battery module M includes the temperature, current, voltage, cell voltage, and state of the bypass mechanism B of the storage battery module M.

[0055] The string controller SC estimates the SOC, SOH, charge / discharge power limit value, etc. of the storage battery module M based on the module state information received from the module controller MC. The SOC, SOH, charge / discharge power limit value, etc. of the storage battery module M may be estimated by the module controller MC. In this case, the module controller MC may transmit the estimation results to the string controller SC.

[0056] The string controller SC estimates the state of the string St based on the module state information received from the module controller MC. Examples of the state of the string St include the string SOH, the string SOC, and the string charge / discharge power limit value. The state of the string St may be estimated by the string system controller SSC. In this case, the string controller SC may transmit the module state information and the estimated result of the state of the storage battery to the string system controller SSC.

[0057] If the estimated values ​​of the cell voltage, the total string current, the state of the string St, etc. are outside the threshold range, the string controller SC determines that the string St is abnormal. In this case, the string controller SC stops the operation of the string St and / or sends an abnormality notification to the string system controller SSC.

[0058] The string controller SC transmits to the string system controller SSC information required for processing by the string system controller SSC, among the information received from the module controller MC and information estimated by itself. Information required for processing by the string system controller SSC includes the temperature, current, voltage, SOC, SOH, charge / discharge power limit value, cell voltage, state of the bypass mechanism B, string SOC, string SOH, string charge / discharge power limit value, etc. of the storage battery module M.

[0059] The string system controller SSC determines instructions for each string St based on the "information required for processing by the string system controller SSC" received from the string controller SC, and transmits the instruction information to the string controller SC. These instructions include a charge / discharge instruction for the string St in the charge / discharge mode, an individual control instruction for the string St in the maintenance mode, and a state estimation instruction for the string St in the state estimation mode. Items of the charge / discharge instruction for the string St in the charge / discharge mode include, in addition to the string charge / discharge power instruction value, the control amount for the constant voltage mode, constant current mode, and constant power mode, and the operation method such as independent operation / grid-connected operation. Items of the individual control instruction for the string St in the maintenance mode include an instruction to individually control the bypass mechanism B. Items of the state estimation instruction in the state estimation mode include, for example, charging / discharging at a constant current and recording the voltage of the storage battery module M during this.

[0060] The string controller SC receives the above-mentioned instruction information for each string St from the string system controller SSC, and determines whether or not the bypass schedule for the string St needs to be updated by comparing the instruction information received this time with the instruction information received last time. The bypass schedule for the string St is a plan for bypassing the storage battery module M by the bypass mechanism B, and is determined based on predetermined criteria. The string controller SC determines whether a switch from charging to discharging or from discharging to charging will occur in the string St, and if such a switch occurs, determines that the bypass schedule needs to be updated. If the bypass schedule needs to be updated, the string controller SC determines the bypass schedule for the storage battery module M based on the storage battery state information received from the module controller MC and the estimated state of the storage battery module M.

[0061] On the other hand, the string controller SC determines 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 controller MC and the estimated result of the storage battery state. If control of the string charge / discharge power is necessary, the string controller SC transmits a control signal corresponding to the string charge / discharge power instruction value received from the string system controller SSC to a control device (not shown) of the power converter PCS.

[0062] When the string controller SC receives a maintenance / stop command from the string system controller SSC, it analyzes the received maintenance / stop command and determines the type of maintenance to be performed. This type of maintenance can include individual control, self-diagnosis, storage battery replacement (hereinafter referred to as storage battery replacement), etc.

[0063] An example of individual control is control for individually turning on / off a cooling device (not shown) in the string St. An example of self-diagnosis is abnormality determination for detecting abnormalities that are difficult to detect during operation in the state estimation mode or the charge / discharge mode. Examples of abnormality determination include performing special control on the power converter PCS or the switches S1, S2 of the bypass mechanism B, acquiring the response thereof using various sensors, and determining whether or not there is an abnormality. An example of battery replacement is providing guidance for replacing a battery in a battery module M that has deteriorated or has failed. When replacing a battery, 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 string St whose battery is to be replaced.

[0064] When the string controller SC receives a state estimation instruction from the string system controller SSC, it compares the currently received string charge / discharge power instruction value with the previously received string charge / discharge power instruction value and determines whether there has been a change. If there is a change in the string charge / discharge power instruction value between the previous and current times, the string controller SC controls the power converter PCS and the switches S1 and S2 of the bypass mechanism B in a predetermined manner so that the state of the string St can be estimated. An example of a method for controlling the power converter PCS and the like during execution of the state estimation mode is a method for constant current control of the power converter PCS. Furthermore, an example of a method for controlling the switches S1 and S2 of the bypass mechanism B during execution of the state estimation mode is a method for sequentially bypassing storage battery modules M that have become fully discharged during discharging.

[0065] The string controller SC records the module state information received from the module controller MC. Furthermore, the string controller SC updates parameters used for state estimation as needed based on the module state information received from the module controller MC. These parameters include the SOH of the storage battery module M, a map of charge / discharge limit values ​​of the storage battery module M, and SOC-OCV (Open Circuit Voltage) characteristics.

[0066] The module controller MC communicates with the string controller SC and the cell monitoring unit. The module controller MC controls the switches S1 and S2 of the bypass mechanism B, the cell monitoring unit, switch S3, etc. The module controller MC receives module status information from the cell monitoring unit, etc. The module status information includes the total voltage of the storage battery module M, the temperature of the storage battery module M, the cell voltage, etc. The cell monitoring unit receives detection signals from various sensors (not shown), such as a module voltage sensor that detects the voltage of the storage battery module M, a cell voltage sensor that detects the cell voltage, and a module temperature sensor that detects the temperature of the storage battery module M. The cell monitoring unit may be configured as a standalone unit, or may be configured using a battery cell monitoring IC (Integrated Circuit) within the module controller MC.

[0067] The module controller MC receives module state information from the cell monitoring unit and estimates the state of the storage battery module M based on the received information. The estimated state of the storage battery module M may include the SOC, SOH, and charge / discharge power limit value of the storage battery module M. Note that the state of the storage battery module M may be estimated by the string controller SC.

[0068] For example, if the detected values ​​of the module voltage sensor, cell voltage sensor, or module temperature sensor or the estimated value of the state of the storage battery module M are outside the threshold range, the module controller MC determines that the storage battery module M is abnormal. Then, the module controller MC shuts off the switch S2 of the bypass mechanism B of the storage battery module M determined to be abnormal, or sends an abnormality notification to the string controller SC.

[0069] The module controller MC transmits to the string controller SC information required for processing by a higher-level controller such as the string controller SC, among the information received from the cell monitoring unit and information estimated by itself. Information required for processing by the string controller SC includes the temperature, current, voltage, SOC, SOH, charge / discharge power limit value, cell voltage, and the state of the switches S1 and S2 of the bypass mechanism B of the storage battery module M.

[0070] The string controller SC determines instructions for each module controller MC based on the "information required for processing by the string controller SC" received from the module controller MC, and transmits the instruction information. Examples of these instructions include bypass control of the storage battery module M by the switches S1 and S2 of the bypass mechanism B, and shut-off control of the storage battery module M by the switch S2 of the bypass mechanism B.

[0071] If there is a change between the current and previous instruction information received from the string controller SC, the module controller MC controls the switches S1 and S2 of the bypass mechanism B to execute the bypass control or shutoff control described above. Furthermore, if there is a change in the information received from the cell monitoring unit and the information estimated by the module controller MC, the module controller MC executes exceptional control as necessary, independent of instructions from a higher-level controller. Furthermore, the module controller MC sends an instruction to the cell monitoring unit to execute cell balancing of the storage battery module M.

[0072] As described above, in order to perform communication between the string controller SC and the multiple module controllers MC, a communication ID needs to be set in each module controller MC. Therefore, in the power storage system 1, a communication ID setting process is executed to set a communication ID for each module controller MC when the power storage system 1 is initially started up or restarted.

[0073] During a communication ID setting process, such as when the power storage system 1 is first started up, the string controller SC performs an automatic communication ID allocation process in which the string controller SC broadcasts a communication ID to all module controllers MC. In response, each module controller MC responds to the automatic communication ID allocation process by the string controller SC according to a predetermined priority. For example, each module controller MC responds to the automatic communication ID allocation process by the string controller SC after a wait time corresponding to a random number generated within an MCU (Micro Control Unit). Alternatively, a collision process is performed for simultaneous responses from multiple module controllers MC, resulting in each module controller MC responding to the automatic communication ID allocation process by the string controller SC. That is, a process of assigning a communication ID to a module controller MC that responds to the automatic communication ID allocation process by the string controller SC is repeated, and communication IDs are set for all module controllers MC. The module controllers MC for which a communication ID has been set do not respond to the automatic communication ID allocation process by the string controller SC.

[0074] Here, the automatic allocation process of a communication ID by the string controller SC and the module controller MC's response to this process are performed regardless of the arrangement (order) of the storage battery modules M within the string St. Therefore, it is necessary to execute a process (hereinafter referred to as an arrangement identification process) to identify the arrangement within the string St of the storage battery module M corresponding to the module controller MC to which a communication ID is set. If this arrangement identification process is not executed, the string controller SC cannot identify the arrangement within the string St of the storage battery module M corresponding to the module controller MC to which a communication ID is set, and the module controller MC itself cannot identify the arrangement within the string St of the storage battery module M corresponding to the communication ID set for itself. In this case, even if an abnormality occurs in a storage battery module M and an abnormality notification is sent to the string controller SC from the module controller MC corresponding to the storage battery module M, the string controller SC cannot identify the arrangement within the string St of the storage battery module M in which the abnormality has occurred.

[0075] Therefore, the storage battery control device 2 according to this embodiment not only performs a communication ID setting process for setting a communication ID in the module controller MC when the power storage system 1 is first started up or restarted, but also performs a placement identification process.

[0076] FIG. 3 is a flowchart illustrating the placement identification process executed by the storage battery control device 2 shown in FIGS. 1 and 2. This placement identification process is executed after the communication ID setting process. In the following description, the communication ID set in each module controller MC will be referred to as ID(n). n is a value for identifying the module controller MC, and n=1 to m. m is the number of module controllers MC and storage battery modules M in the string St.

[0077] The string controller SC stores in advance an array VM(x,n) whose elements are a value (x) for identifying the string St and a value (n) for identifying the module controller MC. In the initial state of the array VM(x,n), n is arranged in the order of n=1, 2, . . . , m.

[0078] Here, ID(n) is not associated with storage battery modules M1-Mm before the start of the processing shown in the flowchart of Fig. 3. Therefore, as described above, for example, ID(1) is set to module controllers MC2-MCm corresponding to storage battery modules M2-Mm other than the starting storage battery module M1, and ID(2) is set to module controllers MC1, MC3-MCm corresponding to storage battery modules M1, M3-Mm other than the second storage battery module M2.

[0079] First, the string controller SC initializes various management parameters and variables (step S101). In this embodiment, n=1. Next, the string controller SC sends a control signal to all module controllers MC to set the bypass release state (step S102). In step S102, all module controllers MC control the switch S1 of the corresponding bypass mechanism B to OFF and the switch S2 to ON. As a result, all storage battery modules M in the string St are connected in series.

[0080] Thereafter, the processes of steps S103 to S108 are repeated from n=1 to n=m. First, the string controller SC transmits a control signal to the module controller MC having the ID(n) set thereto to switch the switch S3 into a connected state (step S103). As a result, the positive electrode of the storage battery module M corresponding to the module controller MC having the ID(n) set thereto is connected to the signal line 131.

[0081] Next, the string controller SC acquires and records the voltage measurement value of the voltage sensor 12 (step S104). Here, when the switch S31 corresponding to the starting storage battery module M1 is in the connected state, the measurement value of the voltage sensor 12 is maximum. As the connected switches S3 move toward the terminal end of the string St (S32, . . . , S3m), the measurement value of the voltage sensor 12 decreases. That is, when the switch S31 is in the connected state, the measurement value of the voltage sensor 12 is V1+V2+···+Vm. V1, V2, . . . , Vm are the voltages of the storage battery modules M1, M2, . . . , Mm, respectively. Furthermore, when the switch S32 is in the connected state, the measurement value of the voltage sensor 12 is V2+···+Vm. Furthermore, when the switch S3m is in the connected state, the measurement value of the voltage sensor 12 is Vm.

[0082] Next, the string controller SC transmits a control signal to the module controller MC having the ID(n) set to turn off the switch S3 (step S105), thereby disconnecting the signal line 131 from the positive electrode of the storage battery module M corresponding to the module controller MC having the ID(n).

[0083] Next, the string controller SC rearranges the values ​​of n in the array VM(x, n) in descending order of the measurement values ​​of the voltage sensor 12 recorded in step S104 (step S106). Specifically, the string controller SC rearranges the values ​​of n in the array VM(x, n) so that the value of n of the ID(n) set in the module controller MC corresponding to switch S31 is first, the value of n of the ID(n) set in the module controller MC corresponding to switch S32 is second, and the value of n of the ID(n) set in the module controller MC corresponding to switch S3m is last.

[0084] Next, the string controller SC increments the value of n (step S107). Next, the string controller SC determines whether instructions to all module controllers MC have been completed (step S108). Specifically, the string controller SC determines whether voltage measurement values ​​by the voltage sensor 12 have been recorded for all ID(n) from n=1 to n=m. If a negative determination is made in step S108, the processes of steps S103 to S108 are repeated, and if a positive determination is made in step S108, the placement identification process is terminated.

[0085] As described above, in the battery control device 2 according to this embodiment, the negative electrode side of the terminal battery module Mm is connected to the positive electrode sides of each of the plurality of battery modules M1 to Mm by a signal line 131. A voltage sensor 12 is provided on the signal line 131. In addition, switches S31 to S3m are provided corresponding to each of the battery modules M1 to Mm. The switches S31 to S3m connect or disconnect the positive electrode side of the corresponding battery module M1 to Mm to the signal line 131 in response to a control signal transmitted by the corresponding module controller MC1 to MCm.

[0086] Here, after setting the communication ID to the module controllers MC1 to MCm, the string controller SC executes an arrangement identification process for identifying the arrangement of the storage battery modules M1 to Mm corresponding to the module controllers MC1 to MCm within the string St. This arrangement identification process includes the following transmission process, acquisition process, and identification process, and is performed for all module controllers MC1 to MCm.

[0087] In a transmission process, the string controller SC transmits a control signal to one of the multiple module controllers MC1 to MCm to close the switch S3. Next, in an acquisition process, the string controller SC acquires a measurement value of the voltage sensor 12 with the switch S3 in a closed state. Next, in an identification process, the string controller SC identifies the arrangement of the storage battery modules M1 to Mm corresponding to the module controllers MC1 to MCm within the string St according to the acquired measurement value of the voltage sensor 12.

[0088] As described above, the storage battery control device 2 according to this embodiment can identify the physical arrangement (order) of the storage battery modules M1-Mm in the string St corresponding to the module controllers MC1-MCm whose communication IDs have been automatically set. Therefore, for example, when the module controllers MC1-MCm notify the string controller SC of an abnormality, the string controller SC can identify the physical arrangement of the abnormal storage battery modules M1-Mm in the string St.

[0089] Furthermore, in the storage battery control device 2 according to this embodiment, the string controller SC stores an array VM having communication IDs as elements, and in the identification process, rearranges the communication IDs in the array VM according to the acquired measurement values ​​of the voltage sensor 12. This allows the string controller SC to refer to the array VM in which the communication IDs have been rearranged and identify the arrangement, within the string St, of the storage battery module M corresponding to the module controller MC to which the communication ID is set.

[0090] Furthermore, in the energy storage system 1 according to this embodiment, bypass mechanisms B1-Bm are provided corresponding to the storage battery modules M1-Mm, respectively. The bypass mechanisms B1-Bm place the corresponding storage battery modules M1-Mm in a bypass state or a bypass release state in response to a control signal transmitted from the corresponding module controller MC1-MCm. In response to this, the string controller SC transmits a control signal to all of the module controllers MC1-MCm to place all of the storage battery modules M1-Mm in the bypass release state before executing the above-described arrangement identification process. This allows the above-described arrangement identification process to be executed with all of the storage battery modules M1-Mm connected in series, and makes it possible to obtain measurement values ​​of different voltage sensors 12 depending on the connected switches S31-S3m.

[0091] 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 within the scope of the spirit of the present invention, and publicly known or well-known technologies may be combined as appropriate.

[0092] For example, in the above embodiment, the value of n in ID(n), which is an element of the array, is sorted in descending order of the measurement values ​​of the voltage sensor 12 acquired in the above placement identification process, but this is not essential. It is sufficient if, as a result of executing the above placement identification process, information is recorded that can identify the correspondence between ID(n) and the placement of the storage battery modules M1 to Mm within the string St according to the measurement values ​​of the voltage sensor 12.

[0093] In the above embodiment, the signal lines 1311 to 131m are connected to the power lines of the string St via the bypass lines BL, but this is not essential. The signal lines 1311 to 131m may be connected directly to the power lines of the string St.

[0094] In addition, in the above-described embodiment, the string controller SC corresponding to the hierarchical level of the string St is the master device, and the multiple module controllers MC corresponding to the hierarchical level of the storage battery modules M are slave devices, but this is not essential. One of the multiple module controllers MC may be the master device, and the other module controllers MC may be slave devices, with the master controller setting communication IDs and transmitting control signals to the slave controllers. [Explanation of symbols]

[0095] 1: Energy storage system 2: Battery control device 12: Voltage sensor 131: Signal line B: Bypass mechanism (bypass section) B1: Bypass mechanism (bypass section) B2: Bypass mechanism (bypass section) Bm: Bypass mechanism (bypass section) M: Battery module M1: Battery module M2: Battery module Mm: Battery module MC: Module controller (module control unit) MC1: Module controller (module control unit) MC2: Module controller (module control unit) MCm: Module controller (module control unit) S3: Switch S31: Switch S32: Switch S3m: Switch SC: String controller (string control section) SC1: String controller (string control section) SC2: String controller (string control section) SCx: String controller (string control unit) St: String St1: String St2: String Stx: String VM: Array

Claims

1. A battery control device for controlling a power storage system including a string in which a plurality of battery modules are connected in series, a plurality of module control units provided corresponding to the storage battery modules; a string control unit provided corresponding to the string, the string control unit setting communication IDs to the plurality of module control units and communicating with the plurality of module control units; a signal line connecting a negative electrode side of the storage battery module arranged closest to the negative electrode side of the string among the plurality of storage battery modules to a positive electrode side of each of the plurality of storage battery modules; a voltage sensor provided on the signal line; a plurality of switches provided corresponding to the storage battery modules, each of which connects or disconnects the positive electrode side of the storage battery module to the signal line in response to a control signal transmitted by the module control unit; Equipped with the string control unit sets the communication ID in the module control unit, and then performs a placement identification process to identify the placement of the storage battery module corresponding to the module control unit within the string; The placement identification process includes: a transmission process of transmitting a control signal to any one of the plurality of module control units to set the switch to a connected state; an acquisition process for acquiring a measurement value of the voltage sensor when the switch is in a connected state; an identification process in which the module control unit identifies the placement of the corresponding storage battery module within the string according to the acquired measurement value; A battery control device including:

2. the string control unit stores an array having the communication ID as an element; The battery control device according to claim 1 , wherein the identification process includes a process of rearranging the communication IDs in the array in accordance with the acquired measurement value.

3. The power storage system includes: a plurality of bypass units provided corresponding to the storage battery modules, the bypass units placing the storage battery modules in a bypass state or a bypass release state in response to a control signal transmitted by the module control unit; Equipped with The battery control device according to claim 1 , wherein the string control unit transmits a control signal to the plurality of module control units to set all of the battery modules to the bypass release state before performing the placement identification process.

4. A power storage system including a string in which a plurality of storage battery modules are connected in series, A power storage system comprising the battery control device according to any one of claims 1 to 3.

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