Storage 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 battery control device and a power storage system.

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage system including a string in which a plurality of battery modules are connected in series, in order to perform communication between a string control unit (master device) corresponding to the string and a plurality of module control units (slave devices) respectively corresponding to the battery modules, a method for setting the communication IDs of the plurality of module control units is considered. Examples of the method include a method in which a user manually sets the communication IDs, and a method in which the string control unit, which is the master device, automatically sets the communication 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 implemented in the module control unit, and the user sets the switch for each module control unit. In this method, if a mistake occurs in the setting of the switch by the user, all communications in the power storage system may become impossible.

[0006] In the method of automatic setting by the string control unit, an automatic allocation process is repeated in which the communication ID is transmitted from the string control unit to a plurality of module control units by broadcast communication and each module control unit sequentially responds. In this method, no association is made between the module control unit assigned the communication ID and the arrangement (order) within the string of the battery modules corresponding to the module control unit. Therefore, for example, when an abnormality notification of a power storage module is made from the module control unit to the string control unit, the string control unit cannot identify the arrangement within the string of the battery module corresponding to the module control unit that made the abnormality notification.

[0007] In view of the above circumstances, the present invention provides a battery control device and a power storage system that, in a power storage system including a string in which a plurality of battery modules are connected in series, automatically set the communication IDs of a plurality of module control units and enable 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 that controls 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 respectively provided corresponding to the battery modules, and a string control unit provided corresponding to the string, which sets communication IDs for the plurality of module control units and communicates with the plurality of module control units, a signal line connecting the negative electrode side of the battery module arranged on the most negative electrode side of the string among the plurality of battery modules and the positive electrode side of each of the plurality of battery modules, a voltage sensor provided on the signal line, and a plurality of switches respectively provided corresponding to the battery modules, which connect or disconnect the positive electrode side of the battery module to the signal line according to a control signal transmitted by the module control unit. After setting the communication ID for the module control unit, the string control unit executes an arrangement identification process for identifying the arrangement of the battery module corresponding to the module control unit in the string. The arrangement identification process includes a transmission process of transmitting a control signal for turning on the switch to any one of the plurality of module control units, an acquisition process of acquiring a measurement value of the voltage sensor when the switch is turned on, and an identification process of identifying the arrangement of the battery module corresponding to the module control unit in the string according 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 battery modules are connected in series, and includes the battery control device according to any one of claims 1 to 3.

Advantages of the Invention

[0010] According to the present invention, in a power storage system including a string in which a plurality of battery modules are connected in series, after automatically setting the communication IDs of the plurality of module control units, the string control unit can identify the arrangement of the battery modules in the string.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in accordance with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and the embodiments can be appropriately changed without departing from the gist of the present invention. Also, in the embodiments shown below, there are some places where the illustration and description of some configurations are omitted. However, regarding the details of the omitted technology, well-known or widely known technologies are appropriately applied within the range where there is no contradiction with the content described below.

[0013] FIG. 1 is a circuit diagram showing the circuit configuration of a power storage system 1 including a power storage battery control device 2 according to an 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.

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

[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 and describe each of the strings St1 to Stx, the strings St1 to Stx are described as string St. Also, when it is not necessary to distinguish and describe each of the power converters PCS1 to PCSx, the power converters PCS1 to PCSx are described as power converter PCS. Further, when it is not necessary to distinguish and describe each of the string controllers SC1 to SCx, the string controllers SC1 to SCx are described as string controller SC.

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

[0017] The battery module M includes a plurality of battery cells C connected in series. The battery cell C is a secondary battery cell such as a lithium ion battery or a lithium ion capacitor, and is charged by receiving power from an external system through a power converter PCS, and discharges the charged power through the power converter PCS to supply power to the external system. Although not particularly limited, the battery module M of the present embodiment is a recycled used battery module and has differences in the degree of deterioration. Note that a battery cell or a battery pack may be provided instead of the battery module M.

[0018] m (an integer of 2 or more) battery modules M1 to Mm are arranged in order from the one with the smallest sign from the positive electrode side to the negative electrode side of the string St. That is, the battery module M1 is arranged on the most positive electrode side in the string St, the battery module M2 is arranged on the negative electrode side of the string St from the battery module M1, and the battery module Mm is arranged on the most negative electrode side in the string St. Note that the battery module M1 on the most positive electrode side in the string St may be described as the starting battery module M1, and the battery module Mm on the most negative electrode side in the string St may be described as the ending 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 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 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 battery module M1 at the start and the battery module Mm at the end are connected to the external power system via the power converter PCS and the 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 power system. The state where the switch S1 is off and the switch S2 is on in the bypass mechanism B is the state where the bypass of the battery module M is released (hereinafter referred to as the bypass release 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 battery module M corresponding to the bypass mechanism B is bypassed. The state where the switch S1 is on and the switch S2 is off in the bypass mechanism B is the state where the 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. Also, the positive electrode side of the battery module M1 at the start and the negative electrode side of the battery module Mm at the end are respectively connected to the power converter PCS.

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

[0024] The power converter PCS converts the voltage input from a plurality of battery modules M during the discharge of the string St and transmits it to the string bus 6. Here, the input voltage of the power converter PCS during discharge varies according to the bypass state of the plurality of battery modules M and the charge state of the plurality of battery modules M. As a result, a variation occurs in the input voltage of the power converter PCS between the strings St during discharge. Therefore, the power converter PCS converts the input voltage into a voltage that matches other strings St and transmits it to the string bus 6 during the discharge of the string St. When the current flowing through the string bus 6 is alternating current, the power converter PCS is provided with synchronization means for following the change in the instantaneous value.

[0025] The cell monitoring unit is connected between the positive and negative terminals of each battery cell C, detects the voltage between the terminals of each battery cell C (hereinafter referred to as the cell voltage), and transmits a detection signal to the module controller MC. In addition, the cell monitoring unit has a cell balancing function and equalizes the cell voltages of the 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 a communication ID for a plurality of module controllers MC in order to communicate with the plurality of module controllers MC. The module controller MC controls the switches S1, S2, and S3 according to the control signal transmitted from the string controller SC.

[0027] The string St is provided with a current sensor 11, a voltage sensor 12, and an arrangement identification circuit 13. The current sensor 11 is provided between the power converter PCS and the positive electrode side of the first battery module M1 of the string St, measures the total current of the string St, and transmits the measured value to the string controller SC. The arrangement of the current sensor 11 is not particularly limited. For example, it may be provided between the negative electrode side of the last battery module Mm and the power converter PCS.

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

[0029] The signal line 131 connects the negative electrode side of the battery module Mm at the end and the positive electrode sides of each of the plurality of battery modules M1 to Mm. The signal line 131 is composed of a signal line 131A connected to the negative electrode side of the battery module Mm at the end, signal lines 1311 to 131m branched 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 that connects the switch S1 in the bypass line BL to the positive electrode of the battery module M.

[0030] The voltage sensor 12 is provided on the signal line 131A and transmits the measured value of the voltage to the string controller SC. The switch S3 is provided on the signal lines 1311 to 131m and connects or disconnects the positive electrode side of the corresponding battery module M to the signal line 131 according to the control signal from the corresponding module controller MC. The switch S3 is, for example, a mechanical switch, a semiconductor switch, or a relay. The switch S3 is preferably a normally open switch but this is not essential.

[0031] When any one of the switches S31 to S3m is turned ON, the positive electrode side of the battery module M corresponding to the switch S3 and the negative electrode side of the battery module Mm at the end are connected by the 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 becomes the sum of the voltages of the 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 the battery module M2 and the negative electrode side of the terminal battery module Mm are connected by the signal line 131. When all bypass mechanisms B are in the bypass release state in this state, the voltage measured by the voltage sensor 12 is the sum of the voltages of the battery modules M2 to Mm. Also, when switch S31 is ON and the other switches S3 are OFF, the positive electrode side of the battery module M1 and the negative electrode side of the terminal battery module Mm are connected by the signal line 131. When all bypass mechanisms B are in the bypass release state in this state, the voltage measured by the voltage sensor 12 is the sum of the voltages of the battery modules M1 to Mm (the total voltage of the string St). Further, when switch S3m is ON and the other switches S3 are OFF, the positive electrode side and the negative electrode side of the battery module Mm are connected by the signal line 131. In this state, the voltage measured by the voltage sensor 12 is the voltage of the 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 battery control device 2. The 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, the string system controller SSC, the string controller SC, and the module controller MC are provided for each hierarchy. The power storage system controller PSC corresponds to the highest hierarchy of the power storage system 1. The string system controller SSC corresponds to the hierarchy of the string system 10 next to the hierarchy of the power storage system 1. The string controller SC corresponds to the hierarchy of the string St next to the hierarchy of the string system 10. The module controller MC corresponds to the hierarchy of the battery module M next to the hierarchy of the string St.

[0035] The power storage system controller PSC communicates with the upper server 7 and the string system controller SSC, and controls and manages the power storage system auxiliary device 3. The upper server 7 is provided in the facilities of the aggregator, the power receiving equipment such as buildings and factories, etc. This upper 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] Examples of the power storage system auxiliary device 3 include a temperature sensor that detects the temperature of the installation environment of the power storage system 1 (such as a container, etc.), fire extinguishing equipment, etc. (both are omitted in the figure). When the detected value of the temperature sensor exceeds the threshold value, the power storage system controller PSC determines that the temperature of the installation environment of the power storage system 1 is abnormal and transmits an abnormality notification to the display input device. In addition, the power storage system controller PSC monitors the operating state of the fire extinguishing equipment.

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

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

[0039] The states of the string system 10 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), the limit value of the charge and discharge power (or charge and discharge current) of the string system 10 (hereinafter referred to as the string system charge and discharge power limit value), and the like.

[0040] 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. The states of the power storage system 1 include operating states such as charging, discharging, halting, and maintenance, the SOC of the power storage system 1 (hereinafter referred to as the power storage system SOC), the SOH of the power storage system 1 (hereinafter referred to as the power storage system SOH), and the like. The power storage system controller PSC transmits information about the estimated state of the power storage system 1 to the display input device as necessary. In this embodiment where the string system 10 is singular, 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. The information required for the processing of the upper server 7 includes the power storage system SOC, the power storage system SOH, the string system charge and discharge power limit value, and the like. Here, based on the "information required for the processing of the upper server 7" received from the power storage system controller PSC, the upper server 7 determines a charge and discharge instruction for the power storage system 1 and transmits it to the power storage system controller PSC. Examples of this charge and discharge instruction include, in addition to the power storage system charge and discharge power instruction value, control quantities such as the constant voltage (CV) mode, the constant current (CC) mode, and the constant power (CP) mode, and operation modes such as autonomous operation / system connection.

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

[0043] 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 devices 5 such as the power converter PCS and the switches S1, S2, and S3. By forcibly operating the power storage system auxiliary device 3, the string system auxiliary device 4, and the string auxiliary devices 5, it becomes possible to confirm the operations of the power storage system auxiliary device 3, the string system auxiliary device 4, and the string auxiliary devices 5.

[0044] Examples of the instruction to forcibly execute charge and discharge include an instruction to forcibly execute charge and discharge on the power storage system 1 by designating a predetermined charge and discharge amount. By forcibly executing charge and discharge on the power storage system 1 by designating a predetermined charge and discharge amount, it becomes possible to confirm whether the power storage system 1 can charge and discharge the designated predetermined charge and discharge amount.

[0045] Examples of the instruction to forcibly execute state estimation include an instruction to forcibly execute state estimation on the power storage system 1 by designating a predetermined state estimation item. By forcibly executing state estimation on the power storage system 1 by designating a predetermined state estimation item, it becomes possible to obtain state estimation items such as the string system SOH and the power storage system SOH at an arbitrary point in time, for example.

[0046] The string system controller SSC communicates with the power storage system controller PSC and a plurality of string controllers SC, and controls and manages the string system compensator 4. Examples of the string system compensator 4 include a temperature sensor that detects the ambient temperature, a cooling device within the string system 10, a cutoff device for the string bus 6, a current sensor that detects the string bus current, a voltage sensor that detects the string bus voltage, etc. (all are not shown in the figure).

[0047] The string system controller SSC receives string state information from a plurality of string controllers SC. Examples of the state of the string St include operating states such as charging, discharging, standby, maintenance, etc., string current, string total voltage, string SOC, string SOH, string charge and discharge power limit value, the state of the string system compensator 4, etc. Examples of the state of the string system compensator 4 include the string bus current, the string bus voltage, etc.

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

[0049] For example, when the detected values of the temperature sensor, current sensor, and voltage sensor or the estimated values of the state of the string system 10 are outside the threshold range, the string system controller SSC determines that the string system 10 is abnormal, and stops the operation of the string system 10 or transmits an abnormality notification to the power storage system controller PSC.

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

[0051] Based on the "information necessary for the processing of the power storage system controller PSC" received from the string system controller SSC, the power storage system controller PSC determines an instruction corresponding to the string system 10 and transmits the instruction information to the string system controller SSC. Examples of this 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), a state estimation instruction for the string system 10 in the state estimation mode, etc. Examples of the charge / discharge instruction for the string system 10 in the charge / discharge mode include, in addition to the charge / discharge power instruction value assigned to each string system 10, instructions such as the control amounts in the constant voltage (CV) mode, constant current (CC) mode, and constant power (CP) mode, and the operation mode such as independent operation / grid connection. Examples of the individual control instruction for the string system 10 in the maintenance mode include instructions to individually control the power converter PCS, the switches S1, S2 of the bypass mechanism B, and the string system compensator 4. Examples of the state estimation instruction for the string system 10 in the state estimation mode include an instruction to execute predetermined control necessary for performing the state estimation of the string St.

[0052] The string system controller SSC receives an instruction corresponding to the above-described string system 10 from the power storage system controller PSC, and determines whether it is necessary to update the operating state of the string system 10 by comparing the instruction received this time with the instruction received last time. When it is necessary to update the operating state of the string system 10, the string system controller SSC determines the operating mode of the string St, the permission for the bypass request from the string controller SC, and the string charge / discharge power instruction value assigned to the string St. Examples of the operating mode of the string St include a charge / discharge mode, a state estimation mode, a maintenance / stop mode, and the like.

[0053] The string controller SC communicates with the string system controller SSC and a plurality of module controllers MC to control and manage the string compensator 5. Examples of the string compensator 5 include a power converter PCS, a current sensor 11 for detecting the string current (see FIG. 1), a voltage sensor for detecting the total string voltage (not shown), and switches S1, S2, S3, and the like.

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

[0055] The string controller SC estimates the SOC, SOH, charge / discharge power limit value, etc. of the battery module M based on the module state information received from the module controller MC. Note that the estimation of the SOC, SOH, charge / discharge power limit value, etc. of the battery module M may be performed by the module controller MC. In this case, the module controller MC may transmit the estimation result 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, the string charge / discharge power limit value, etc. Note that the estimation of the state of the string St may be performed by the string system controller SSC. In this case, the string controller SC may transmit the module state information and the estimation result of the state of the battery to the string system controller SSC.

[0057] When the cell voltage, the total string current, the estimated value of 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 may stop the operation of the string St or transmit an abnormality notification to the string system controller SSC.

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

[0059] The string system controller SSC determines an instruction for each string St based on the "information required for the processing of the string system controller SSC" received from the string controller SC, and transmits the instruction information to the string controller SC. Examples of such instructions include charge / discharge instructions for the string St in the charge / discharge mode, individual control instructions for the string St in the maintenance mode, and state estimation instructions for the string St in the state estimation mode. Examples of the 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, control amounts in the constant voltage mode, constant current mode, and constant power mode, and operation modes such as self-operation / grid connection. Examples of the items of the individual control instruction for the string St in the maintenance mode include an instruction to individually control the bypass mechanism B. Examples of the items of the state estimation instruction in the state estimation mode include performing charge / discharge at a constant current and recording the voltage of the battery module M at that time.

[0060] The string controller SC receives the above-mentioned instruction information for each string St from the string system controller SSC, and determines whether it is necessary to update the bypass schedule of the string St by comparing the currently received instruction information with the previously received instruction information. The bypass schedule of the string St is a plan regarding the bypass of the battery module M by the bypass mechanism B and is determined based on a predetermined criterion. The string controller SC determines whether the switching from charging to discharging or from discharging to charging is performed in the string St, and determines that it is necessary to update the bypass schedule when such switching is performed. When it is necessary to update the bypass schedule, the string controller SC determines the bypass schedule of the battery module M based on the battery state information received from the module controller MC and the estimation result of the state of the battery module M.

[0061] On the other hand, the string controller SC determines the necessity of controlling the string charge / discharge power by comparing the module state information received from the module controller MC and the estimation result of the state of the storage battery between this time and the previous time. When the 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 the control device (not shown) of the power converter PCS.

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

[0063] Examples of individual control include controlling to individually turn on / off a cooling device (not shown) in the string St. Examples of self-diagnosis include abnormality determination for abnormalities that were difficult to determine during operation in the state estimation mode or charge / discharge mode. Examples of this abnormality determination include performing special control on the power converter PCS or switches S1, S2, etc. of the bypass mechanism B, and determining the presence or absence of an abnormality by acquiring the response with various sensors. Examples of storage battery replacement include guiding the replacement of the storage battery module M in which deterioration has progressed or a failure has occurred. During storage battery replacement, a work guide is displayed on the display input device of the power storage system controller PSC, and necessary controls such as stopping the string St targeted for storage battery replacement are executed in the power storage system 1.

[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 to determine whether there has been a change. When there is a change in the string charge / discharge power instruction value between the previous and current times, the string controller SC controls the switches S1 and S2 of the power converter PCS and the bypass mechanism B in a predetermined manner so that the state estimation of the string St is possible. Examples of the control method of the power converter PCS and the like during the execution of the state estimation mode include a method of controlling the power converter PCS with a constant current. Also, examples of the control method of the switches S1 and S2 of the bypass mechanism B during the execution of the state estimation mode include a method of sequentially bypassing the battery modules M that have been fully discharged during discharge.

[0065] The string controller SC records the module state information received from the module controller MC. Also, the string controller SC updates the parameters used when performing state estimation as needed based on the module state information received from the module controller MC. Examples of this parameter include the SOH of the battery module M, the map of the charge / discharge limit values of the battery module M, the SOC-OCV (Open Circuit Voltage) characteristics, and the like.

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

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

[0068] For example, when the detection values of the module voltage sensor, the cell voltage sensor, the module temperature sensor and the estimated value of the state of the battery module M are out of the threshold range, the module controller MC determines that the battery module M is abnormal. Then, the module controller MC shuts off the battery module M determined to be abnormal with the switch S2 of the bypass mechanism B or transmits an abnormality notification to the string controller SC.

[0069] The module controller MC transmits, to the string controller SC, the information received from the cell monitoring unit and the information estimated by itself that is required for the processing of the upper controller such as the string controller SC. Examples of the information required for the processing of the string controller SC include the temperature, current, voltage, SOC, SOH, charge / discharge power limit value of the battery module M, cell voltage, and the states of the switches S1 and S2 of the bypass mechanism B.

[0070] Based on the "information required for the processing of the string controller SC" received from the module controller MC, the string controller SC determines an instruction for each module controller MC and transmits the instruction information. Examples of this instruction include bypass control of the battery module M by the switches S1 and S2 of the bypass mechanism B, cutoff control of the battery module M by the switch S2 of the bypass mechanism B, etc.

[0071] When there is a change in the instruction information received from the string controller SC between this time and the previous time, the module controller MC controls the switches S1 and S2 of the bypass mechanism B and executes the above-mentioned bypass control or cutoff control. Also, when there is a change in the information received from the cell monitoring unit and the information estimated by itself, the module controller MC executes exception control that does not depend on the instruction from the upper controller as necessary. In addition, the module controller MC transmits an instruction to execute cell balancing of the battery module M to the cell monitoring unit.

[0072] As described above, in order to communicate between the string controller SC and a plurality of module controllers MC, it is necessary to set a communication ID for each module controller MC. Therefore, in the power storage system 1, a communication ID setting process for setting a communication ID for each module controller MC is executed at the first startup, restart, etc.

[0073] In the communication ID setting process at the first startup of the power storage system 1 or the like, the string controller SC executes an automatic allocation process of communication IDs, in which it transmits communication IDs to all module controllers MC by broadcast communication. In response thereto, each module controller MC responds to the automatic allocation process of communication IDs by the string controller SC according to a predetermined priority order. For example, each module controller MC responds to the automatic allocation process of communication IDs by the string controller SC after a waiting time corresponding to a random number generated in the MCU (Micro Control Unit). Alternatively, collision processing is performed for responses at the same timing from a plurality of module controllers MC, and as a result, each module controller MC responds to the automatic allocation process of communication IDs by the string controller SC. That is, the process of assigning communication IDs to the module controllers MC that can respond to the automatic allocation process of communication IDs by the string controller SC is repeated, so that communication IDs are set for all module controllers MC. Note that the module controller MC to which the communication ID has been set does not respond to the automatic allocation process of communication IDs by the string controller SC.

[0074] Here, the automatic allocation process of the communication ID by the string controller SC and the response of the module controller MC to the process are performed regardless of the arrangement (order) within the string St of the battery module M. Therefore, it is necessary to execute a process (hereinafter referred to as the arrangement identification process) for identifying the arrangement within the string St of the battery module M corresponding to the module controller MC to which the 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 battery module M corresponding to the module controller MC with the communication ID set, and the module controller MC itself cannot identify the arrangement within the string St of the battery module M corresponding to the communication ID set for itself. In that case, when an abnormality occurs in the battery module M, even if an abnormality notification is transmitted from the module controller MC corresponding to the battery module M to the string controller SC, the string controller SC cannot identify the arrangement within the string St of the battery module M where the abnormality occurred.

[0075] Therefore, the battery control device 2 according to the present embodiment executes not only the communication ID setting process for setting the communication ID to the module controller MC but also the arrangement identification process at the first startup or restart of the power storage system 1 and the like.

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

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

[0078] Here, before the start of the process shown in the flowchart of FIG. 3, the ID(n) is not associated with the battery modules M1 to Mm. Therefore, for example, the module controllers MC2 to MCm corresponding to the battery modules M2 to Mm other than the battery module M1 with ID(1) at the start end may be set, or ID(2) may be set to the module controllers MC1, MC3 to MCm corresponding to the battery modules M1, M3 to Mm other than the second battery module M2, as described above.

[0079] First, the string controller SC initializes various management parameters and variables (step S101). In the present embodiment, n = 1. Next, the string controller SC transmits a control signal for putting all the module controllers MC into a bypass release state (step S102). In step S102, all the module controllers MC control the switch S1 of the corresponding bypass mechanism B to OFF and the switch S2 to ON. Thereby, all the 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 for connecting the switch S3 in the connected state to the module controller MC to which the ID(n) is set (step S103). Thereby, the positive electrode of the battery module M corresponding to the module controller MC to which the ID(n) is set is connected to the signal line 131.

[0081] Next, the string controller SC acquires and records the measured voltage value by the voltage sensor 12 (step S104). Here, when the switch S31 corresponding to the battery module M1 at the start end is in the connected state, the measured value of the voltage sensor 12 becomes the maximum. As the switches S3 that become connected states are S32, ···, S3m and approach the end side of the string St, the measured value of the voltage sensor 12 decreases. That is, when the switch S31 is in the connected state, the measured value of the voltage sensor 12 becomes V1 + V2 + ··· + Vm. V1, V2, ···, Vm are the voltages of the battery modules M1, M2, ···, Mm, respectively. Also, when the switch S32 is in the connected state, the measured value of the voltage sensor 12 becomes V2 + ··· + Vm. Further, when the switch S3m is in the connected state, the measured value of the voltage sensor 12 becomes Vm.

[0082] Next, the string controller SC transmits a control signal for turning off the switch S3 to the module controller MC with ID(n) set (step S105). Thereby, the connection between the positive electrode of the battery module M corresponding to the module controller MC with ID(n) set and the signal line 131 is cut off.

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

[0084] Next, the string controller SC increments the value of n (step S107). Next, the string controller SC determines whether the instructions for all the module controllers MC have been completed (step S108). Specifically, the string controller SC determines whether the voltage measurement values by the voltage sensor 12 have been recorded for all the IDs(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. If a positive determination is made in step S108, the arrangement identification process is terminated.

[0085] As described above, in the battery control device 2 according to the present embodiment, the negative electrode side of the terminal battery module Mm and the positive electrode side of each of the plurality of battery modules M1 to Mm are connected by the signal lines 131, respectively. The voltage sensor 12 is provided on the signal line 131. Further, the switches S31 to S3m are provided corresponding to the battery modules M1 to Mm, respectively. The switches S31 to S3m connect or disconnect the positive electrode sides of the corresponding battery modules M1 to Mm to the signal line 131 in accordance with the control signals transmitted by the corresponding module controllers 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 arrangements of the module controllers MC1 to MCm in the string St of the corresponding battery modules M1 to Mm. This arrangement identification process includes the following transmission process, acquisition process, and identification process, and is performed for all the module controllers MC1 to MCm.

[0087] In the transmission process, the string controller SC transmits a control signal for connecting the switch S3 to any one of the plurality of module controllers MC1 to MCm. Next, in the acquisition process, the string controller SC acquires the measured value of the voltage sensor 12 in the state where the switch S3 is connected. Next, in the identification process, the string controller SC identifies the arrangement of the battery modules M1 to Mm corresponding to the module controllers MC1 to MCm in the string St according to the acquired measured value of the voltage sensor 12.

[0088] As described above, according to the battery control device 2 according to the present embodiment, the physical arrangement (order) of the battery modules M1 to Mm corresponding to the module controllers MC1 to MCm with automatically set communication IDs in the string St can be identified. Therefore, for example, when an abnormality notification is sent from the module controllers MC1 to MCm to the string controller SC, the string controller SC can identify the physical arrangement of the abnormal battery modules M1 to Mm in the string St.

[0089] In addition, in the battery control device 2 according to the present embodiment, the string controller SC stores an array VM including communication IDs, and in the identification process, rearranges the communication IDs of the array VM according to the acquired measured value of the voltage sensor 12. Thereby, the string controller SC can identify the arrangement of the battery module M corresponding to the module controller MC with the communication ID set by referring to the array VM in which the communication IDs are rearranged.

[0090] In addition, in the power storage system 1 according to the present embodiment, bypass mechanisms B1 to Bm are provided corresponding to battery modules M1 to Mm, respectively. The bypass mechanisms B1 to Bm set the corresponding battery modules M1 to Mm in a bypass state or a bypass release state according to control signals transmitted by the corresponding module controllers MC1 to MCm. On the other hand, before executing the above-described arrangement identification process, the string controller SC transmits control signals for setting all the battery modules M1 to Mm in a bypass release state to all the module controllers MC1 to MCm. Thereby, the above-described arrangement identification process can be executed in a state where all the battery modules M1 to Mm are connected in series, and it becomes possible to acquire measurement values of different voltage sensors 12 according to the connected switches S31 to S3m.

[0091] As described above, the present invention has been described based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and modifications may be made without departing from the spirit of the present invention, or known and well-known techniques may be appropriately combined.

[0092] For example, in the above-described embodiment, the values of n of ID(n) which are elements of the array are sorted in descending order of the measurement values of the voltage sensor 12 acquired by the above-described arrangement identification process, but this is not essential. As long as information is recorded such that the correspondence between ID(n) and the arrangement in the string St of the battery modules M1 to Mm can be specified according to the measurement values of the voltage sensor 12 as a result of executing the above-described arrangement identification process.

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

[0094] In the above-described embodiment, the string controller SC corresponding to the hierarchy of the string St is used as the master device, and the plurality of module controllers MC corresponding to the hierarchy of the battery module M are used as slave devices. However, this is not essential. Any one of the plurality of module controllers MC may be used as the master device, and the other module controllers MC may be used as slave devices, and the master controller may set a communication ID or transmit a control signal to the slave controller.

Explanation of Signs

[0095] 1: Power 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 section) MC1: Module controller (module control section) MC2: Module controller (module control section) MCm: Module controller (module control section) 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 section) 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 respectively provided corresponding to the battery modules, a string control unit provided corresponding to the string, configured to set a communication ID to the plurality of module control units and communicate with the plurality of module control units, a signal line connecting the negative electrode side of the battery module arranged on the most negative electrode side of the string among the plurality of battery modules and the positive electrode side of each of the plurality of battery modules, a voltage sensor provided on the signal line, and a plurality of switches respectively provided corresponding to the battery modules, configured to connect or disconnect the positive electrode side of the battery module to / from the signal line according to a control signal transmitted by the module control unit, wherein, after setting the communication ID to the module control unit, the string control unit executes an arrangement identification process for identifying the arrangement of the battery module corresponding to the module control unit within the string, the arrangement identification process includes, a transmission process of transmitting a control signal for turning on the switch to any one of the plurality of module control units, an acquisition process of acquiring a measured value of the voltage sensor when the switch is turned on, and an identification process of identifying the arrangement of the battery module corresponding to the module control unit within the string according to the acquired measured value. A battery control device comprising the above.

2. The string control unit stores an array including the communication ID, and the identification process includes a process of rearranging the communication ID of the array according to the acquired measured value. The battery control device according to Claim 1.

3. The power storage system includes, a plurality of bypass units respectively provided corresponding to the battery modules, configured to put the battery module into a bypass state or a bypass release state according to a control signal transmitted by the module control unit, wherein, before executing the arrangement identification process, the string control unit transmits a control signal for setting all the battery modules to the bypass release state to the plurality of module control units. The battery control device according to Claim 1.

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

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