Battery control device and power storage system

Abstract

To manage the amount of stored power in units of storage battery strings and in units of storage batteries even in a large-scale power storage system and appropriately suppress the processing load of a control device.SOLUTION: A storage battery control apparatus 2 comprises: a plurality of first control devices 21 provided for each of strings ST1-STx and controlling a string auxiliary unit 5; and a second control device 22 communicating with the plurality of first control devices 21 and a host server 7 outside of a power storage system 1. Information regarding the states of the strings ST1-STx is acquired and transmitted to the second control device 22 by the first control devices 21. Based on a charge / discharge power instruction value of the power storage system 1 received from the host server 7 and the information regarding the states of the plurality of strings ST1-STx received from the plurality of first control devices 21, a charge / discharge power instruction values to be allocated to each of the plurality of strings ST1-STx is calculated and transmitted to the first control device 21 by the second control device 22.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] A power storage system including a plurality of battery strings connected in parallel is known (see, for example, Patent Document 1). In the power storage system described in Patent Document 1, a battery string includes a plurality of batteries connected in series and a power converter. This power converter is controlled by a controller to convert the output of the battery string into a set voltage of a load supply bus.

[0003] Also, as a power storage system including a plurality of battery strings connected in parallel, there is known one including a plurality of bypass switch units provided for each of a plurality of batteries connected in series and a plurality of string cutoff switches provided for each battery string (see, for example, Patent Document 2). In the power storage system described in Patent Document 2, the bypass switch unit is controlled by a controller to switch the battery between a connected state and a bypass state. Also, the string cutoff switch is controlled by a controller to switch the battery string between a connected state and a cutoff state.

[0004] Furthermore, a power storage system that executes temperature adjustment control of a battery in response to a demand response (hereinafter referred to as DR) request is known (see, for example, Patent Document 3). In the power storage system described in Patent Document 3, when performing charge / discharge control to mitigate a power shortage in the power grid, execution of temperature adjustment control is restricted.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Assume a large-scale power storage system including a large number of battery strings, each of which is provided with a power converter, a large number of batteries, and a large number of bypass switch units. In this assumption, in order to execute charge / discharge control in response to a DR request, it is necessary to manage the stored power in units of battery strings and units of batteries. However, in a large-scale power storage system, since the number of battery strings is large and the number of batteries is even larger, measures are required to avoid the complication of control by the control device and appropriately suppress the processing load of the control device.

[0007] In view of the above circumstances, an object of the present invention is to provide a battery control device and a power storage system that can manage the stored power in units of battery strings and units of batteries even in a large-scale power storage system and appropriately suppress the processing load of the control device.

Means for Solving the Problems

[0008] The battery control device of the present invention includes a plurality of battery strings connected in parallel, and each of the battery strings includes a plurality of batteries connected in series, a plurality of bypass circuits provided for each of the batteries to switch the battery between a bypass state and a connected state, and a power converter for converting the input / output power of the battery string. The battery control device controls a power storage system, and includes a plurality of first control units provided for each of the battery strings to control accessories of the battery string including the power converter and the bypass circuit, and a second control unit for communicating with a system outside the power storage system and the plurality of first control units. The first control unit acquires information about the state of the battery string and transmits it to the second control unit. The second control unit calculates an instruction value of charge / discharge power or charge / discharge current to be assigned to each of the plurality of battery strings based on an instruction value of charge / discharge power or charge / discharge current of the power storage system received from a system outside the power storage system and information about the states of the plurality of battery strings received from the plurality of first control units, and transmits the calculated instruction value to the first control unit. The first control unit controls the accessories of the battery string according to the instruction value of charge / discharge power or charge / discharge current of the battery string received from the second control unit.

[0009] The power storage system of the present invention includes a plurality of battery strings connected in parallel and a battery control device. Each of the battery strings includes a plurality of batteries connected in series, a plurality of bypass circuits provided for each of the batteries to switch the battery between a bypass state and a connected state, and a power converter for converting the input / output power of the battery string. The battery control device includes a plurality of first control units provided for each of the battery strings to control the auxiliary devices of the battery string including the power converter and the bypass circuits, and a second control unit for communicating with the plurality of first control units and a system outside the power storage system. The first control unit acquires information about the state of the battery string and transmits it to the second control unit. The second control unit calculates an instruction value for the charge / discharge power or charge / discharge current to be assigned to each of the plurality of battery strings based on the instruction value of the charge / discharge power or charge / discharge current of the power storage system received from a system outside the power storage system and the information about the states of the plurality of battery strings received from the plurality of first control units, and transmits the calculated instruction value to the first control unit. The first control unit controls the auxiliary devices of the battery string according to the instruction value of the charge / discharge power or charge / discharge current of the battery string received from the second control unit.

Advantages of the Invention

[0010] According to the present invention, in a large-scale power storage system, the stored power can be managed in units of battery strings and units of batteries, and the processing load of the control device can be appropriately suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the present invention will be described in accordance with preferred embodiments. It should be noted 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. For the details of the omitted technologies, well-known or well-understood technologies are appropriately applied within the range where there is no contradiction with the content described below.

[0013] FIG. 1 is a perspective view showing a power storage system 1 including a battery control device 2 (see FIG. 4) according to an embodiment of the present invention. As shown in this figure, the power storage system 1 is a stationary power source and includes a string system 10, a container C that houses the string system 10, and a power storage system controller PSC. The string system 10 includes a number of strings ST1 to STx.

[0014] Container C removably houses a large number of trays T arranged vertically and horizontally. String ST1 to STx are placed on each tray T. Also, the power storage system controller PSC is a control device that communicates with the upper server 7 and the string system controller SSC described later and controls the power storage system compensator 3 (see FIG. 4). The power storage system controller PSC also includes a display input device 8 such as a touch panel having a display function and an input function. The upper server 7, the power storage system compensator 3, and the string system controller SSC will be described later.

[0015] FIG. 2 is a perspective view showing the string STx included in the power storage system 1 shown in FIG. 1. As shown in this figure, the string STx includes a large number of storage batteries B1 to Bx and a battery connection module 100.

[0016] The string STx includes a large number of storage batteries B1 to Bx connected in series. Although not particularly limited, the storage batteries B1 to Bx in this embodiment are those obtained by regenerating used storage batteries, and there are differences in the degree of deterioration of each storage battery B1 to Bx. The storage batteries B1 to Bx are provided with a positive electrode terminal and a negative electrode terminal to which a wire harness WH for power supply is connected. The storage batteries B1 to Bx are secondary batteries such as lithium ion batteries and lithium ion capacitors, for example, and are charged by receiving power from an external system (not shown) through a power converter PCx, and discharge the charged power through the power converter PCx to supply power to the external system. The external system includes loads such as home appliances and commercial power supply systems in the home and generators such as solar power generation systems.

[0017] The storage batteries B1 to Bx are battery modules in which a large number of battery cells are connected in series. Note that the storage batteries B1 to Bx may be battery packs in which a plurality of battery modules are connected in series, or may be single battery cells.

[0018] The storage batteries B1 to Bx are arranged in two rows, and a battery connection module 100 is arranged between the rows. The battery connection module 100 includes a base plate 101, a plurality of bypass switch units BSU1 to BSUx, and a plurality of bus bars 102. Further, the battery connection module 100 includes a current sensor 13, a power converter PCx, a service plug 140, and a string controller SCx. Furthermore, the battery connection module 100 includes a wire harness unit 160 for communication and power supply, and a power supply wire harness WH.

[0019] On the other hand, the battery connection module 100 includes a plurality of connection units CU1 to CUx arranged linearly. The power converter PCx and the current sensor 13 are provided in the leading connection unit CU1. Following this connection unit CU1, the connection units CU2 to CUx are arranged in order.

[0020] The battery connection module 100 includes a plurality of bypass switch units BSU1 to BSUx. The bypass switch units BSU1 to BSUx are provided for each of the storage batteries B1 to Bx. Further, the plurality of bypass switch units BSU1 to BSUx are provided in pairs of two in any one of the connection units CU2 to CUx.

[0021] The storage batteries B1 to Bx are arranged in the order of B1, B2, …, Bx in the connection direction of the storage batteries B1 to Bx, while the bypass switch units BSU1 to BSUx are arranged in the order of BSU1, BSU2, …, BSUx in the connection direction of the storage batteries B1 to Bx. The bypass switch unit BSU1 is connected to the positive and negative terminals of the storage battery B1 by a wire harness WH for power supply. Also, the bypass switch unit BSU1 is connected to the communication and power supply connection terminals (not shown) of the storage battery B1 by a wire harness for communication and power supply (not shown). Similarly, the bypass switch units BSU2 to BSUx are each connected to the positive and negative terminals of the storage batteries B2 to Bx by a wire harness WH for power supply, and are connected to the communication and power supply connection terminals of the storage batteries B2 to Bx by a wire harness for communication and power supply. The configurations of the bypass switch units BSU1 to BSUx are common. Note that the details of the configurations of the bypass switch units BSU1 to BSUx will be described later.

[0022] The power converter PCx is, for example, a bidirectional DC / DC converter, and includes a positive terminal 131 on the primary side during discharge, a negative terminal 132 on the primary side during discharge, a positive terminal on the secondary side during discharge (not shown), and a negative terminal on the secondary side during discharge (not shown). The positive terminal 131 is connected to the input terminal of the bypass switch unit BSU1 of the connection unit CU2 by the bus bar 102. Also, the negative terminal 132 is connected to the current sensor 13 by the bus bar 102. This current sensor 13 is connected to the output terminal of the bypass switch unit BSUx of the connection unit CU2 by the bus bar 102.

[0023] The output terminal of the bypass switch unit BSU1 and the input terminal of the bypass switch unit BSU2 are connected by the bus bar 102. Similarly, among the plurality of bypass switch units BSU2 to BSUx, those adjacent to each other in the connection direction of the storage batteries B1 to Bx are connected by the bus bar 102. Here, among the plurality of bypass switch units BSU1 to BSUx, those adjacent to each other in the connection direction of the storage batteries B1 to Bx are mechanically connected by the bus bar 102, thereby constituting a base plate 101 in which a plurality of plates 101A are integrated.

[0024] Figure 3 is a circuit diagram showing the circuit configuration of the power storage system 1 shown in Figure 1. As shown in this figure, the power storage system 1 includes a power storage system controller PSC and a string system 10. In this embodiment, the number of string systems 10 is one, but there may be a plurality of string systems 10.

[0025] The string system 10 includes a string system controller SSC, a number of strings ST1 to STx, and a string bus 6. The number of strings ST1 to STx are connected in parallel to each other via the string bus 6 and are connected to an external system (not shown).

[0026] Each of the strings ST1 to STx includes one string controller SC1 to SCx, one power converter PC1 to PCx, one string cutoff switch 11, and a number of modules M1 to Mx. Each of the modules M1 to Mx includes one storage battery B1 to Bx, one bypass switch unit BSU1 to BSUx, one voltage sensor 12, and one module controller MC1 to MCx. Here, each of the strings ST1 to STx includes a number of storage batteries B1 to Bx connected in series and a number of bypass switch units BSU1 to BSUx provided for each of the storage batteries B1 to Bx. Further, each of the strings ST1 to STx includes one current sensor 13, one voltage sensor 14, one fuse 15, the same number of voltage sensors 12 as the storage batteries B1 to Bx, and temperature sensors (not shown), and cell voltage sensors (both not shown) having the same number as the storage battery cells.

[0027] The power converters PC1 to PCx are bidirectional converters and are connected to the string bus 6. Further, the positive electrode of the starting storage battery B1 and the negative electrode of the ending storage battery Bx are connected to the power converters PC1 to PCx.

[0028] When charging the strings ST1 to STx, the power converters PC1 to PCx convert the voltage input from the string bus 6 and output it to the plurality of storage batteries B1 to Bx according to an instruction value of a charging power (or charging current) described later (hereinafter referred to as a charging power instruction value). Here, the voltage on the side of the strings ST1 to STx changes according to the bypass state of the storage batteries B1 to Bx (the number of the storage batteries B1 to Bx that are bypassed) and the charging state of the storage batteries B1 to Bx. Therefore, when charging the strings ST1 to STx, the power converters PC1 to PCx convert the voltage input from the string bus 6 into the voltage on the side of the strings ST1 to STx and output it to the plurality of storage batteries B1 to Bx.

[0029] Power converters PC1 to PCx convert the voltage input from a plurality of storage batteries B1 to Bx during the discharge of strings ST1 to STx and output it to string bus 6 according to an instruction value of the subsequent discharge power (or discharge current) (hereinafter referred to as discharge power instruction value). Here, the input voltage of power converters PC1 to PCx during discharge changes according to the bypass state of storage batteries B1 to Bx and the charge state of storage batteries B1 to Bx. As a result, a variation occurs in the input voltage of power converters PC1 to PCx among strings ST1 to STx during discharge. Therefore, power converters PC1 to PCx convert the input voltage into a voltage that matches that of other strings ST1 to STx and output it to string bus 6 during the discharge of strings ST1 to STx. When the current flowing through string bus 6 is alternating current, power converters PC1 to PCx are provided with synchronization means for following the change in the instantaneous value.

[0030] String cut-off switches 11 are provided between each of power converters PC1 to PCx and string bus 6. These string cut-off switches 11 connect or disconnect strings ST1 to STx with respect to string bus 6. Further, fuses 15 are power fuses provided between string cut-off switches 11 and string bus 6.

[0031] The voltage sensor 12 is connected between the positive and negative terminals of each storage battery B1 to Bx, detects the terminal voltage of each storage battery B1 to Bx, and transmits a detection signal to the module controllers MC1 to MCx. Also, the current sensor 13 is provided on the power line PL of each string ST1 to STx, detects the charge and discharge current of each string ST1 to STx (hereinafter referred to as the string current), and transmits a detection signal to the string controllers SC1 to SCx. Further, the voltage sensor 14 is provided on the power line PL of each string ST1 to STx, detects the total voltage of each string ST1 to STx (hereinafter referred to as the string total voltage), and transmits a detection signal to each string controller SC1 to SCx. Also, the temperature sensor is provided on each storage battery B1 to Bx, detects the temperature of each storage battery B1 to Bx, and transmits a detection signal to each module controller MC1 to MCx. Furthermore, the cell voltage sensor is provided for each storage battery cell of each storage battery B1 to Bx, detects the voltage of the storage battery cell, and transmits a detection signal to each module controller MC1 to MCx.

[0032] The bypass switch units BSU1 to BSUx are provided for each of the storage batteries B1 to Bx. Each bypass switch unit BSU1 to BSUx includes a bypass line BL and switches S1, S2. The bypass line BL is a power line that bypasses each storage battery B1 to Bx. The switch S1 is provided on the bypass line BL. This switch S1 is, for example, a mechanical switch, a semiconductor switch, or a relay. The switch S2 is provided between the positive electrode of each storage battery B1 to Bx and one end of the bypass line BL. This switch S2 is, for example, a mechanical switch, a semiconductor switch, or a relay.

[0033] The battery B1 at the start and the battery Bx at the end are connected to an external system (not shown) via the power converters PC1 to PCx and the string bus 6. When the switch S1 is turned off and the switch S2 is turned on in all the bypass switch units BSU1 to BSUx, all the batteries B1 to Bx are connected in series to the external system. On the other hand, when the switch S2 is turned off and the switch S1 is turned on in any of the bypass switch units BSU1 to BSUx, the batteries B1 to Bx corresponding to the bypass switch unit BSU1 to BSUx are bypassed.

[0034] Figure 4 is a block diagram showing the control configuration of the power storage system 1 shown in Figure 1. As shown in this figure, the power storage system 1 includes a battery control device 2. The battery control device 2 includes a plurality of first control devices 21 and a second control device 22. The first control device 21 includes a large number of string controllers SC1 to SCx and an even larger number of module controllers MC1 to MCx. The second control device 22 includes a power storage system controller PSC and a string system controller SSC.

[0035] The power storage system controller PSC, the string system controller SSC, the string controllers SC1 to SCx, and the module controllers MC1 to MCx are provided for each layer. The power storage system controller PSC corresponds to the highest layer of the power storage system 1. The string system controller SSC corresponds to the layer of the string system 10 next to the layer of the power storage system 1. The string controllers SC1 to SCx correspond to the layers of the strings ST1 to STx next to the layer of the string system 10. The module controllers MC1 to MCx correspond to the layers of the modules M1 to Mx (see Figure 3) next to the layers of the strings ST1 to STx. Hereinafter, the controllers corresponding to each layer will be described.

[0036] <Power Storage System Controller PSC> 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 compensator 3. The upper server 7 is provided in facilities of an aggregator, power receiving equipment such as buildings and factories, etc. This upper server 7 calculates an instruction value of charge / discharge power (or charge / discharge current) for the entire power storage system 1 (hereinafter referred to as the 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.

[0037] Examples of the power storage system compensator 3 include a temperature sensor that detects the temperature inside the container C (see Fig. 1), an opening / closing sensor that detects the opening / closing of the door of the container C, fire extinguishing equipment, etc. (all 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 inside the container C is abnormal and outputs an abnormality notification to the display input device 8 (see Fig. 1). Also, when the opening of the door is detected by the opening / closing sensor, the power storage system controller PSC outputs a notification of door opening to the display panel. Furthermore, the power storage system controller PSC monitors the operating state of the fire extinguishing equipment.

[0038] The power storage system controller PSC receives information about the states of the strings ST1 to STx (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 outputs them to the upper server 7 or the display panel.

[0039] Examples of the states of the strings ST1 to STx include operating states such as charging, discharging, standby, maintenance, etc., string current, string total voltage, SOC (State of Charge) of the strings ST1 to STx (hereinafter referred to as string SOC), SOH (State of Health) of the strings ST1 to STx (hereinafter referred to as string SOH), and limit values of input / output current (or input / output current) of the strings ST1 to STx (hereinafter referred to as string input / output power limit values), etc.

[0040] As the states of the string system 10, there are the current of the string bus 6 (see FIG. 3) (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 input / output power (or input / output current) of the string system 10 (hereinafter referred to as the string system input / output power limit value), and the like.

[0041] 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. As the states of the power storage system 1, there are the operating states such as charging, discharging, standby, 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 outputs the information about the estimated state of the power storage system 1 (hereinafter referred to as the power storage system state information) to the display panel as necessary. In the present 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.

[0042] The power storage system controller PSC transmits information required for the processing of the upper server 7 to the upper server 7. Examples of the information required for the processing of the upper server 7 include the power storage system SOC, the power storage system SOH, the string system input / output power limit value, etc. 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 / discharge instruction corresponding to the power storage system 1 and transmits it to the power storage system controller PSC. Examples of this charge / discharge instruction include, in addition to the charge / 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 independent operation and grid connection.

[0043] The power storage system controller PSC transmits various instruction information input by an operator or the like using the display input device 8 to the string system controller SSC. Examples of the various instruction information that can be input using the display input device 8 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 / discharge, and an instruction to forcibly execute state estimation.

[0044] Examples of the maintenance / stop instruction include an instruction to forcibly operate the power storage system compensator 3, the string system compensator 4, and the string compensator 5. By forcibly operating the power storage system compensator 3, the string system compensator 4, and the string compensator 5, it becomes possible to confirm the operation of the power storage system compensator 3, the string system compensator 4, and the string compensator 5.

[0045] Examples of the instruction to forcibly execute charge / discharge include an instruction to specify a predetermined charge / discharge amount and forcibly execute charge / discharge on the power storage system 1. By specifying a predetermined charge / discharge amount and forcibly executing charge / discharge on the power storage system 1, it becomes possible to confirm whether the power storage system 1 can input / output the specified predetermined charge / discharge amount.

[0046] Examples of an instruction to force the execution of state estimation include an instruction to force the power storage system 1 to execute state estimation by specifying a predetermined state estimation item. By specifying a predetermined state estimation item and forcing the power storage system 1 to execute state estimation, 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.

[0047] FIG. 5 is a flowchart for explaining the processing of the power storage system controller PSC. The processing shown in this flowchart starts when the power storage system 1 is operated and proceeds to step S1, and steps S2 to S9 are repeated while the power storage system 1 is operating.

[0048] In step S1, the power storage system controller PSC initializes various parameters. Next, in step S2, the power storage system controller PSC receives string state information and string system state information from the string system controller SSC. The power storage system controller PSC outputs the string state information and the string system state information to the display input device 8 as necessary.

[0049] Next, in step S3, the power storage system controller PSC acquires information (hereinafter referred to as power storage system auxiliary device state information) about the state of the power storage system auxiliary device 3 (temperature of the container C, open / closed state of the door, etc.) from the power storage system auxiliary device 3. The power storage system controller PSC outputs the power storage system auxiliary device state information to the display input device 8 as necessary.

[0050] Next, in step S4, 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 in step S2. The power storage system controller PSC outputs information about the state of the power storage system (hereinafter referred to as power storage system state information) to the display input device 8 as necessary. Note that the estimation of the state of the power storage system 1 may be performed by the string system controller SSC. In that case, the string system controller SSC may transmit the estimation result to the power storage system controller PSC.

[0051] Next, in step S5, the power storage system controller PSC analyzes the information acquired in steps S2 to S4 and determines whether there is an abnormality in the power storage system 1. The power storage system controller PSC determines whether there is an abnormality in the power storage system 1 by, for example, comparing various detected values and estimated values received in steps S2 to S4 with threshold values. The power storage system controller PSC outputs the determination result regarding the presence or absence of an abnormality in the power storage system 1 to the display input device 8 as necessary.

[0052] Next, in step S6, the power storage system controller PSC transmits the information required for the processing of the upper server 7 among the information acquired in steps S2 to S5 to the upper server 7. Next, in step S7, the power storage system controller PSC receives instruction information such as a charge / discharge power instruction value transmitted from the upper server 7. Here, the upper server 7 determines an instruction corresponding to the power storage system 1 based on the information received from the power storage system controller PSC in step S6, and transmits instruction information such as a charge / discharge power instruction value to the power storage system controller PSC in step S7.

[0053] Next, in step S8, the power storage system controller PSC compares the instruction information received from the upper server 7 this time and last time, and determines whether it is necessary to update the operating state of the string system 10. For example, when there is a change in the charge / discharge power value received from the upper server 7 between the previous time and this time, the power storage system controller PSC determines that it is necessary to update the operating state of the string system 10. If an affirmative determination is made in step S8, the process proceeds to step S9; if a negative determination is made in step S8, the process proceeds to step S2.

[0054] In step S9, the power storage system controller PSC transmits the instruction information such as the charge / discharge power instruction value received in step S7 to the string system controller SSC. The process proceeds from step S9 to step S2. Hereinafter, steps S2 to S9 are repeated during the operation of the power storage system 1.

[0055] <String system controller SSC> The string system controller SSC shown in FIG. 4 communicates with the power storage system controller PSC and a number of string controllers SC1 to SCx, 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 in the string system 10, a cutoff device for the string bus 6, a current sensor that detects the current of the string bus 6, a voltage sensor that detects the voltage of the string bus 6, and the like.

[0056] The string system controller SSC receives string state information from the string controllers SC1 to SCx. Examples of the states of the strings ST1 to STx include operating states such as charging, discharging, resting, and maintenance, string current, string total voltage, string SOC, string SOH, string charge / discharge power limit value, and the state of the string system compensator 4. Examples of the state of the string system compensator 4 include string bus current and string bus voltage.

[0057] The string system controller SSC estimates the state of the string system 10 based on the string state information received from the string controllers SC1 to SCx. Examples of the state of the string system 10 include string bus current, string bus voltage, string system SOC, string system SOH, string system input / output power limit value, and the like. Note that the estimation of the state of the string system 10 may be performed by the power storage system controller PSC. The power storage system controller PSC may receive the string state information from the string system controller SSC, estimate the state of the string system 10, and estimate the state of the power storage system 1 based on the estimation result.

[0058] For example, when the detected values of a temperature sensor, a current sensor, a voltage sensor, or the estimated value of the state of the string system 10 exceed the threshold range, the string system controller SSC determines the presence or absence of an abnormality in the string system 10, and may stop the operation of the string system 10 or transmit an abnormality notification to the power storage system controller PSC.

[0059] 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 the string controllers SC1 to SCx and the information estimated by itself. Examples of the information necessary for the processing of the power storage system controller PSC include string system SOC, string system SOH, string system input / output power limit value, and the like.

[0060] Here, the power storage system controller PSC determines an instruction corresponding to the string system 10 based on the "information required for the processing of the power storage system controller PSC" received from the string system controller SSC, and transmits the instruction information to the string system controller SSC. Such instructions include charge / discharge instructions for the string system 10 in the charge / discharge mode, instructions for individually controlling each part of the string system 10 in the maintenance mode (hereinafter referred to as individual control instructions), state estimation instructions for the string system 10 in the state estimation mode, and the like. As the charge / discharge instruction for the string system 10 in the charge / discharge mode, in addition to the charge / discharge power instruction value, instructions such as control amounts in the constant voltage (CV) mode, constant current (CC) mode, and constant power (CP) mode, and operation modes such as independent operation / system connection are included. As the individual control instructions for the string system 10 in the maintenance mode, instructions for individually controlling the power converters PC1 to PCx, the cooling device (not shown), and the string system compensator 4 such as switches S1 and S2 are included. As the state estimation instruction for the string system 10 in the state estimation mode, an instruction for executing predetermined control necessary for performing state estimation of each string ST1 to STx is included.

[0061] The string system controller SSC receives the 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 operation state of the string system 10 by comparing the currently received instruction with the previously received instruction. When it is necessary to update the operation state of the string system 10, the string system controller SSC determines the operation mode of each string ST1 to STx, permission for bypass requests from each string controller SC1 to SCx (hereinafter referred to as bypass permission), and the charge / discharge power instruction value assigned to each string ST1 to STx. Examples of the operation mode of each string ST1 to STx include the charge / discharge mode, the state estimation mode, the maintenance / stop mode, and the like.

[0062] Here, the string system controller SSC determines the operation mode, bypass permission, and charge / discharge power instruction value of each string ST1 to STx based on the operation history of each string ST1 to STx from the past to the present. Examples of the determination of the operation mode and the like based on the operation history from the past to the present include the following (1) to (4). (1) Based on the implementation timing of the state estimation of each string ST1 to STx, determine whether to perform the state estimation of each string ST1 to STx. (2) Based on the presence or absence and timing of the abnormality determination of each string ST1 to STx, determine whether to perform maintenance on each string ST1 to STx or whether to execute charge / discharge of each string ST1 to STx. (3) According to the presence or absence of bypass requests from each string controller SC1 to SCx, determine the charge / discharge power instruction value of each string ST1 to STx. For example, determine the charge / discharge power instruction value of the strings ST1 to STx corresponding to the string controllers SC1 to SCx that have sent bypass requests to be 0. After the completion of the bypass control of the strings ST1 to STx, increase the charge / discharge power instruction value for the strings ST1 to STx. (4) Based on the string SOC, string SOH, and total string voltage of each string ST1 to STx, determine the charge / discharge power instruction value of each string ST1 to STx.

[0063] Figure 6 is a flowchart for explaining the processing of the string system controller SSC. The processing shown in this flowchart starts when the power storage system 1 is operated and proceeds to step S11, and steps S12 to S26 are repeated while the power storage system 1 is operating.

[0064] In step S11, the string system controller SSC initializes various parameters. Next, in step S12, the string system controller SSC receives string state information from each string controller SC1 to SCx.

[0065] Next, in step S13, the string system controller SSC receives string system compensator state information (such as string bus voltage, string bus current, etc.) from the string system compensator 4.

[0066] Next, in step S14, the string system controller SSC estimates the state of the string system 10 based on the string state information received in step S12 and the string system compensator state information received in step S13. Note that the estimation of the state of the string system 10 may be performed by the power storage system controller PSC, and the estimation result may be transmitted from the power storage system controller PSC to the string system controller SSC and the upper server 7.

[0067] Next, in step S15, the string system controller SSC analyzes the information received in steps S12 to S14 and determines whether there is an abnormality in the string system 10. The string system controller SSC determines whether there is an abnormality in the string system 10, for example, by comparing various detected values and estimated values received in steps S12 to S14 with threshold values.

[0068] Next, in step S16, the string system controller SSC transmits the information received in steps S12 to S15 that is required for the processing of the power storage system controller PSC and the upper server 7 to the power storage system controller PSC. Next, in step S17, the string system controller SSC receives an instruction transmitted from the power storage system controller PSC. Here, the power storage system controller PSC determines an instruction (such as a charge / discharge power instruction value in the charge / discharge mode) corresponding to the string system 10 based on the information received from the string system controller SSC in step S16, and transmits it to the string system controller SSC in step S17.

[0069] Next, in step S18, the string system controller SSC compares the current and previous instructions received from the power storage system controller PSC, and determines whether it is necessary to update the operating states of strings ST1 to STx. For example, when there is a change in the charge / discharge power instruction value received from the power storage system controller PSC between the previous and current times, the string system controller SSC determines that it is necessary to update the operating states of strings ST1 to STx. Also, for example, when there is a change in the individual control instruction in the maintenance mode received from the power storage system controller PSC between the previous and current times, the string system controller SSC determines that it is necessary to update the operating states of strings ST1 to STx. If an affirmative determination is made in step S18, the process proceeds to step S19; if a negative determination is made in step S18, the process proceeds to step S12.

[0070] Next, in step S19, the string system controller SSC determines instructions for each string controller SC1 to SCx according to predetermined conditions. Examples of the predetermined conditions include the states of strings ST1 to STx acquired in step S12, the operating history of strings ST1 to STx from the past to the present, and various instructions input by the display input device 8. Examples of the items of instructions for each string controller SC1 to SCx include the operating modes of strings ST1 to STx (state estimation mode, charge / discharge mode, maintenance / stop mode, etc.), permission / non-permission for bypass requests from each string controller SC1 to SCx, and allocation of charge / discharge power instruction values to strings ST1 to STx. When a maintenance / stop instruction is input by the display input device 8, the string system controller SSC determines the instructions for strings ST1 to STx as the maintenance / stop instruction. Similarly, when an instruction to forcibly execute charge / discharge or state estimation is input by the display input device 8 of the power storage system controller PSC, the string system controller SSC determines the instructions for strings ST1 to STx as the charge / discharge instruction or the state estimation instruction.

[0071] Next, in step S20, the string system controller SSC sets a count value m for managing the transmission of instruction information to the string controllers SC1 to SCx to an initial value (m = 1). Next, in step S21, the string system controller SSC determines whether the operation modes of the target strings ST1 to STx for the instruction are any of the charge / discharge mode, the state estimation mode, and the maintenance / stop mode. If it is the charge / discharge mode, it proceeds to step S23. If it is the state estimation mode, it proceeds to step S22. If it is the maintenance / stop mode, it proceeds to step S24.

[0072] In step S22, the string system controller SSC transmits a state estimation instruction to the target string controllers SC1 to SCx. The items of the state estimation instruction include turning on the state estimation mode flag, the charge / discharge power instruction value, bypass permission / non - permission, etc. In the state estimation mode of each string ST1 to STx, for example, discharging is performed at a constant current, and data such as voltage is acquired during that time. Here, if there is a variation in the degree of deterioration of the storage batteries B1 to Bx within each string ST1 to STx, the storage batteries B1 to Bx will reach full discharge in order from the one with the largest degree of deterioration. And each time the storage batteries B1 to Bx reach full discharge, a bypass request is transmitted from the module controllers MC1 to MCx. Thereby, the string system controller SSC determines whether to notify bypass permission for the received bypass request and transmits a notification of bypass permission / non - permission to the string controllers SC1 to SCx.

[0073] On the other hand, in step S23, the string system controller SSC transmits a charge / discharge instruction to the target string controllers SC1 to SCx. The items of the charge / discharge instruction include turning on the charge / discharge mode flag, the charge / discharge power instruction value, bypass permission / non-permission, etc. When there are fully discharged or fully charged batteries B1 to Bx, a bypass request is transmitted from the module controllers MC1 to MCx. Thereby, the string system controller SSC determines whether to notify bypass permission for the received bypass request, and transmits a bypass permission / non-permission notification to the string controllers SC1 to SCx.

[0074] On the other hand, in step S24, the string system controller SSC transmits a maintenance / stop instruction to the target string controllers SC1 to SCx. The items of the maintenance / stop instruction include turning on the maintenance / stop flag, various instructions, bypass permission / non-permission, etc. The various instructions are instructions corresponding to the instructions input by the display input device 8. For example, instructions to forcibly operate the power storage system compensator 3, the string system compensator 4, and the string compensator 5, the bypass switch units BSU1 to BSUx, etc. are included. Here, when an instruction to forcibly operate the bypass switch units BSU1 to BSUx is input by the display input device 8, the string system controller SSC transmits a bypass permission / non-permission instruction to the string controllers SC1 to SCx. Note that the maintenance / stop instruction may be transmitted not only when input by the display input device 8, but also when an abnormality occurs or periodically.

[0075] Transition from steps S22, S23, and S24 to step S25. In step S25, the string system controller SSC increments by 1 a count value m for managing the transmission of instruction information to string controllers SC1 to SCx. Next, in step S26, the string system controller SSC determines whether the transmission of instruction information to all the string controllers SC1 to SCx has been completed. Specifically, the string system controller SSC determines whether the count value m has reached the total number x of the string controllers SC1 to SCx. If a negative determination is made in step S26, the process proceeds to step S21, and steps S21 to S26 are repeated. On the other hand, if an affirmative determination is made in step S26, the process proceeds to step S12, and steps S12 to S26 are repeated during the operation of the power storage system 1.

[0076] <string controllers SC1 to SCx> The string controllers SC1 to SCx shown in FIG. 4 communicate with the string system controller SSC and a number of module controllers MC1 to MCx to control and manage the string compensator 5. Examples of the string compensator 5 include power converters PC1 to PCx, a current sensor 13 for detecting the string current, a voltage sensor 14 for detecting the total string voltage, a string cutoff switch 11, etc. (all shown in FIG. 3).

[0077] The string controllers SC1 to SCx receive information about the states of the storage batteries B1 to Bx (hereinafter referred to as storage battery state information) from the module controllers MC1 to MCx. Examples of the states of the storage batteries B1 to Bx include the temperature, current, voltage, cell voltage, and states of the bypass switch units BSU1 to BSUx of the storage batteries B1 to Bx.

[0078] The string controllers SC1 to SCx estimate the SOC, SOH, input / output power limit values, etc. of the storage batteries B1 to Bx based on the storage battery state information received from the module controllers MC1 to MCx. Note that the module controllers MC1 to MCx may also estimate the SOC, SOH, input / output power limit values, etc. of the storage batteries B1 to Bx. In this case, the module controllers MC1 to MCx may simply send the estimation results to the string controllers SC1 to SCx.

[0079] The string controllers SC1 to SCx estimate the states of the strings ST1 to STx based on the storage battery state information received from the module controllers MC1 to MCx. Examples of the states of the strings ST1 to STx include the string SOH, the string SOC, and the input / output power limit values of the strings ST1 to STx (hereinafter referred to as the string input / output power limit values). Note that the string system controller SSC may also estimate the states of the strings ST1 to STx. In this case, the string controllers SC1 to SCx may simply send the storage battery state information and the estimation results of the states of the storage batteries to the string system controller SSC.

[0080] For example, when the detected values of the current sensor 13 and the voltage sensor 14 and the estimated values of the states of the strings ST1 to STx are outside the threshold ranges, the string controllers SC1 to SCx determine whether there are any abnormalities in the strings ST1 to STx. In this case, the string controllers SC1 to SCx may stop the operation of the strings ST1 to STx or send an abnormality notification to the string system controller SSC.

[0081] The string controllers SC1 to SCx transmit, to the string system controller SSC, the information received from the module controllers MC1 to MCx and the information estimated by themselves that is required for the processing of the string system controller SSC. Examples of the information required for the processing of the string system controller SSC include the temperature, current, voltage, SOC, SOH, input / output power limit values, cell voltage of the storage batteries B1 to Bx, the states of the bypass switch units BSU1 to BSUx, the string SOC, the string SOH, the string input / output power limit values, and the like.

[0082] Here, based on the "information required for the processing of the string system controller SSC" received from the string controllers SC1 to SCx, the string system controller SSC determines instructions corresponding to each of the strings ST1 to STx and transmits the instruction information to the string controllers SC1 to SCx. Examples of such instructions include charge / discharge instructions for each of the strings ST1 to STx in the charge / discharge mode, individual control instructions for each of the strings ST1 to STx in the maintenance mode, state estimation instructions for each of the strings ST1 to STx in the state estimation mode, and the like. Examples of the items of the charge / discharge instructions for each of the strings ST1 to STx in the charge / discharge mode include, in addition to the charge / discharge power instruction value, the control amounts in the constant voltage mode, constant current mode, and constant power mode, and the operation modes such as self-operation / grid connection. Examples of the items of the individual control instructions for each of the strings ST1 to STx in the maintenance mode include instructions for individually controlling the bypass switch units BSU1 to BSUx. Examples of the items of the state estimation instructions in the state estimation mode include performing charge / discharge at a constant current and recording the terminal voltage of the storage batteries B1 to Bx at that time.

[0083] The string controllers SC1 to SCx receive the instruction information corresponding to the respective strings ST1 to STx from the string system controller SSC, and determine whether it is necessary to update the bypass schedule of each of the strings ST1 to STx by comparing the currently received instruction information with the previously received instruction information. The bypass schedule of each of the strings ST1 to STx is a plan regarding the bypass of the storage batteries B1 to Bx by the bypass switch units BSU1 to BSUx, and is determined based on a predetermined criterion. The string controllers SC1 to SCx determine whether the charging-to-discharging or discharging-to-charging switching is performed in each of the strings ST1 to STx, and when such switching is performed, determine that it is necessary to update the bypass schedule. When it is necessary to update the bypass schedule, the string controllers SC1 to SCx determine the bypass schedule of the storage batteries B1 to Bx based on the storage battery state information received from the module controllers MC1 to MCx and the estimation result of the states of the storage batteries B1 to Bx.

[0084] On the other hand, the string controllers SC1 to SCx determine whether it is necessary to control the string input / output power by comparing the current and previous storage battery state information received from the module controllers MC1 to MCx and the estimation result of the states of the storage batteries B1 to Bx. When it is necessary to control the string input / output power, the string controllers SC1 to SCx control the power converters PC1 to PCx.

[0085] The string controllers SC1 to SCx control the power converters PC1 to PCx according to the charge / discharge power instruction values received from the string system controller SSC.

[0086] When the string controllers SC1 to SCx receive a maintenance / stop instruction from the string system controller SSC, they analyze the received maintenance / stop instruction and determine the type of maintenance to be executed. Examples of this type of maintenance include individual control, self-diagnosis, replacement of the storage batteries B1 to Bx (hereinafter referred to as storage battery replacement), etc.

[0087] Examples of individual control include controlling the string cut-off switch 11, the cooling devices in strings ST1 to STx, etc. to be individually turned on and off. Examples of self-diagnosis include abnormal determination for abnormalities that were difficult to determine during operation in the state estimation mode or charge / discharge mode. As for the abnormal determination, special control is performed on the string compensators 5 such as the power converters PC1 to PCx and the bypass switch units BSU1 to BSUx, etc., and the response is acquired by various sensors to determine the presence or absence of abnormalities. Examples of battery replacement include guiding the replacement of the deteriorated batteries B1 to Bx or the failed batteries B1 to Bx. During battery replacement, a work guide is displayed on the display input device 8 of the energy storage system controller PSC, and necessary control such as stopping the strings ST1 to STx targeted for battery replacement is executed in the energy storage system 1. Note that the strings ST1 to STx that are not targeted for battery replacement may be operated in the charge / discharge mode. Also, after the completion of battery replacement, the strings ST1 to STx for which battery replacement has been performed are operated in the state estimation mode, and the battery state information is transmitted from the module controllers MC1 to MCx to the string controllers SC1 to SCx. Note that the strings ST1 to STx that are not targeted for battery replacement may be operated in the charge / discharge mode.

[0088] When the string controllers SC1 to SCx receive a state estimation instruction from the string system controller SSC, they compare the currently received string input / output power instruction value with the previously received string input / output power instruction value to determine whether there has been a change. When there is a change in the string input / output power instruction value between the previous and current times, the string controllers SC1 to SCx control the string compensator 5 and the bypass switch units BSU1 to BSUx in a predetermined manner so that the state estimation of the strings ST1 to STx is possible. Examples of the control method of the string compensator 5 during the execution of the state estimation mode include turning on the string cut-off switch 11 and controlling the power converters PC1 to PCx in constant current mode. Examples of the control method of the bypass switch units BSU1 to BSUx during the execution of the state estimation mode include sequentially bypassing the batteries B1 to Bx that have been fully discharged during discharge.

[0089] The string controllers SC1 to SCx record the battery state information received from the module controllers MC1 to MCx. Also, the string controllers SC1 to SCx update, as necessary, the parameters used for state estimation based on the battery state information received from the module controllers MC1 to MCx. Examples of such parameters include the SOH of the batteries B1 to Bx, the map of the input / output limit values of the batteries B1 to Bx, and the SOC-OCV characteristics.

[0090] <Charge and Discharge Mode> Figures 7 to 9 are flowcharts for explaining the processing of the string controllers SC1 to SCx. The processing shown in this flowchart starts when the power storage system 1 is operated and proceeds to step S31, and steps S32 to S66 are repeated while the power storage system 1 is operating.

[0091] In step S31, the string controllers SC1 to SCx initialize various parameters. Next, in step S32, the string controllers SC1 to SCx receive battery state information from each module controller MC1 to MCx. Next, in step S33, the string controllers SC1 to SCx estimate the states (SOC, SOH, input / output power limit values, etc.) of the batteries B1 to Bx based on the battery state information received in step S32.

[0092] Next, in step S34, the string controllers SC1 to SCx receive string compensator state information from the string compensator 5. Examples of the state of the string compensator 5 include the string total voltage, the string current, the state of the string disconnect switch 11, the states of the power converters PC1 to PCx, etc.

[0093] Next, in step S35, the string controllers SC1 to SCx estimate the states of the strings ST1 to STx based on the information received in steps S32 to S34. Note that the estimation of the states of the strings ST1 to STx may be performed by the string system controller SSC. In this case, the string system controller SSC may transmit the estimation results to the string controllers SC1 to SCx and the power storage system controller PSC.

[0094] Next, in step S36, the string controllers SC1 to SCx analyze the information received in steps S32 to S34 and the estimation results in step S35, and determine whether there is an abnormality in the strings ST1 to STx. The string controllers SC1 to SCx determine whether there is an abnormality in the strings ST1 to STx, for example, by comparing various detection values and estimation values obtained in steps S32 to S35 with threshold values.

[0095] Next, in step S37, the string controllers SC1 to SCx transmit, to the string system controller SSC, the information obtained in steps S32 to S36 that is required for the processing by the higher-level controllers and the higher-level server 7. Next, in step S38, the string controllers SC1 to SCx receive the instruction information transmitted from the string system controller SSC. Here, based on the information received from the string controllers SC1 to SCx in step S37, the string system controller SSC determines instructions corresponding to the strings ST1 to STx (such as the string input / output power instruction values, bypass permission / non-permission in the charge / discharge mode and the state estimation mode, and the individual control instructions in the maintenance mode), and transmits the instruction information to the string controllers SC1 to SCx in step S38.

[0096] Next, in step S39, the string controllers SC1 to SCx determine whether the instruction information received from the string system controller SSC in step S38 includes a charge / discharge instruction. If an affirmative determination is made in step S39, the process proceeds to step S40. If a negative determination is made in step S39, the process proceeds to step S51 in FIG. 8. In step S39, the string controllers SC1 to SCx may determine whether the instruction is related to any of the charge / discharge mode, the maintenance / stop mode, and the state estimation mode. In that case, if the instruction is related to the charge / discharge mode, the process proceeds to step S40. If the instruction is related to the maintenance / stop mode, the process proceeds to step S51 in FIG. 8. If the instruction is related to the state estimation mode, the process proceeds to step S61 in FIG. 9.

[0097] In step S40 of FIG. 7, the string controllers SC1 to SCx compare the charge / discharge instruction received in step S38 with the previously received charge / discharge instruction, and determine whether it is necessary to update the bypass schedule and whether it is necessary to control the string input / output power. The string controllers SC1 to SCx determine, for example, whether a charge-to-discharge or discharge-to-charge switching is performed in each of the strings ST1 to STx, and when such a switching is performed, it is determined that it is necessary to update the bypass schedule. On the other hand, the string controllers SC1 to SCx determine whether it is necessary to control the string input / output power by comparing the information received from the module controllers MC1 to MCx or estimated by themselves this time with the previous time. In step S40, when an affirmative determination is made for at least one of whether it is necessary to update the bypass schedule and whether it is necessary to control the string input / output power as described above, the process proceeds to step S41. On the other hand, in step S40, when a negative determination is made for both whether it is necessary to update the bypass schedule and whether it is necessary to control the string input / output power as described above, the process proceeds to step S44.

[0098] In step S41, the string controllers SC1 to SCx determine the bypass schedule of the batteries B1 to Bx based on the battery state information received from the module controllers MC1 to MCx and the estimated results of the states of the batteries B1 to Bx. Next, in step S42, the string controllers SC1 to SCx control the string compensator 5 based on the information obtained in steps S32 to S38. The string controllers SC1 to SCx perform, for example, the operation of a cooling device (not shown) in the strings ST1 to STx, the control of the string cutoff switch 11, etc.

[0099] Next, in step S43, after the condition for executing bypass control is satisfied, the string controllers SC1 to SCx execute bypass control. The string controllers SC1 to SCx compare the battery state information (such as the SOH of the batteries B1 to Bx) received in step S32, the bypass permission / non - permission received in step S38, and the bypass schedule determined in step S41, and determine whether the above condition is satisfied or not.

[0100] Next, in step S44, the string controllers SC1 to SCx control the power converters PC1 to PCx according to the string input / output power instruction value received from the string system controller SSC in step S38. The process proceeds from step S44 to step S51 in FIG. 8.

[0101] <Maintenance / Stop Mode> In step S51 of FIG. 8, the string controllers SC1 to SCx determine whether the maintenance / stop instruction is included in the instruction information received from the string system controller SSC in step S38 of FIG. 7. If an affirmative determination is made in step S51, the process proceeds to step S52. If a negative determination is made in step S51, the process proceeds to step S61 in FIG. 9.

[0102] In step S52 of FIG. 8, the string controllers SC1 to SCx compare the maintenance / stop instruction received in step S38 with the previously received maintenance / stop instruction, and determine whether there is a change in the maintenance / stop instruction. If an affirmative determination is made in step S52, the process proceeds to step S53. If a negative determination is made in step S52, the process proceeds to step S61 in FIG. 9.

[0103] In step S53 of FIG. 8, the string controllers SC1 to SCx analyze the maintenance / stop instruction received from the string system controller SSC in step S38 and determine the type of maintenance to be executed. If the type of maintenance to be executed is individual control, the process proceeds to step S54. If the type of maintenance to be executed is self-diagnosis, the process proceeds to step S57. If the type of maintenance to be executed is battery replacement, the process proceeds to step S58.

[0104] In step S54, the string controllers SC1 to SCx determine whether the individual control instruction input by the display input device 8 includes an operation check of the string compensator 5. If it is included, the control of the string compensator 5 is executed. Examples of the control of the string compensator 5 include control to individually operate the string cutoff switch 11 and the cooling devices in the strings ST1 to STx.

[0105] Next, in step S55, the string controllers SC1 to SCx determine whether the individual control instruction input by the display input device 8 includes an operation check of the bypass switch units BSU1 to BSUx. If it is included, the control of the bypass switch units BSU1 to BSUx is executed. Next, in step S56, the string controllers SC1 to SCx determine whether the individual control instruction input by the display input device 8 includes an operation check of the power converters PC1 to PCx. If it is included, the control of the power converters PC1 to PCx is executed. The process proceeds from step S56 to step S61 of FIG. 9.

[0106] On the other hand, in step S57, the string controllers SC1 to SCx execute special control for the string compensator 5, the bypass switch units BSU1 to BSUx, etc. for self-diagnosis. At this time, the string controllers SC1 to SCx determine the presence or absence of abnormalities in the strings ST1 to STx based on the detection information detected by various sensors. The process proceeds from step S57 to step S61 of FIG. 9.

[0107] Also, in step S58, the string controllers SC1 to SCx execute necessary control for the string compensator 5 for battery replacement according to an instruction input by an operator to the display input device 8. The process proceeds from step S58 to step S61 in FIG. 9.

[0108] <State Estimation Mode> In step S61 of FIG. 9, the string controllers SC1 to SCx determine whether the instruction information received from the string system controller SSC in step S38 of FIG. 7 includes a state estimation instruction. If an affirmative determination is made in step S61, the process proceeds to step S62; if a negative determination is made in step S61, the process proceeds to step S32 of FIG. 7.

[0109] In step S62 of FIG. 9, the string controllers SC1 to SCx compare the string input / output power instruction value received in step S38 with the previously received string input / output power instruction value, and determine whether there is a change in the string input / output power instruction value. If an affirmative determination is made in step S62, the process proceeds to step S63; if a negative determination is made in step S62, the process proceeds to step S32 of FIG. 7.

[0110] In step S63 of FIG. 9, the string controllers SC1 to SCx control the string compensator 5 in a predetermined method so that the state of the strings ST1 to STx can be estimated. Next, in step S64, the string controllers SC1 to SCx control the bypass switch units BSU1 to BSUx in a predetermined method for estimating the state of the strings ST1 to STx.

[0111] Next, in step S65, the string controllers SC1 to SCx control the power converters PC1 to PCx according to the string input / output power instruction value received in step S38 of FIG. 7. Next, in step S66, the string controllers SC1 to SCx record the battery state information received from the module controllers MC1 to MCx. Further, the string controllers SC1 to SCx update, as necessary, the parameters used when performing state estimation based on the battery state information received from the module controllers MC1 to MCx. The process proceeds from step S66 to step S32 of FIG. 7, and steps S32 to S66 are repeated during the operation of the power storage system 1.

[0112] <module controllers MC1 to MCx> The module controllers MC1 to MCx shown in FIG. 4 communicate with the string controllers SC1 to SCx and control and manage a module compensator (not shown). Examples of this module compensator include bypass switch units BSU1 to BSUx and various sensors. Examples of the various sensors include a voltage sensor that detects the voltage of the storage batteries B1 to Bx, a current sensor that detects the current of the storage batteries B1 to Bx, a temperature sensor that detects the temperature of the storage batteries B1 to Bx, and a cell voltage sensor that detects the cell voltage.

[0113] The module controllers MC1 to MCx receive battery state information from a cell monitoring unit (not shown) or the like. Examples of the state of the storage batteries B1 to Bx include the total voltage of the storage batteries B1 to Bx, the temperature of the storage batteries B1 to Bx, and the cell voltage. The cell monitoring unit receives detection signals from various sensors such as a module voltage sensor that detects the module voltage, a cell voltage sensor that detects the cell voltage, and a module temperature sensor that detects the module temperature. Note that the cell monitoring unit may be configured as a single unit or may be configured by using a battery cell monitoring IC in the module controllers MC1 to MCx.

[0114] The module controllers MC1 to MCx receive the battery state information from the above-mentioned cell monitoring unit or various sensors of the batteries B1 to Bx, and estimate the states of the batteries B1 to Bx based on the received information. Examples of the states of the batteries B1 to Bx to be estimated include the SOC, SOH, input / output power limit values, etc. of the batteries B1 to Bx. Note that the estimation of the states of the batteries B1 to Bx may be performed by the string controllers SC1 to SCx.

[0115] For example, when the detected values of the voltage sensor, cell voltage sensor, module temperature sensor or the estimated values of the states of the batteries B1 to Bx are outside the threshold range, the module controllers MC1 to MCx determine the presence or absence of abnormalities in the batteries B1 to Bx. Then, the module controllers MC1 to MCx cut off the abnormal batteries B1 to Bx with the bypass switch units BSU1 to BSUx, or send an abnormality notification to the string controllers SC1 to SCx.

[0116] The module controllers MC1 to MCx transmit the information necessary for the processing of the upper controllers such as the string controllers SC1 to SCx, among the information received from the cell monitoring unit or various sensors and the information estimated by themselves, to the string controllers SC1 to SCx. Examples of the information necessary for the processing of the string controllers SC1 to SCx include the temperature, current, voltage, SOC, SOH, input / output power limit values, cell voltage, and the states of the bypass switch units BSU1 to BSUx of the batteries B1 to Bx.

[0117] Here, based on the "information necessary for the processing of the string controllers SC1 to SCx" received from the module controllers MC1 to MCx, the string controllers SC1 to SCx determine the instructions corresponding to the respective batteries B1 to Bx and transmit the instruction information to the module controllers MC1 to MCx. Examples of this instruction include bypass control of the batteries B1 to Bx by the bypass switch units BSU1 to BSUx, cutoff control of the batteries B1 to Bx by the bypass switch units BSU1 to BSUx, etc.

[0118] When there are changes in the instruction information received by module controllers MC1 to MCx from string controllers SC1 to SCx between this time and the previous time, the module controllers MC1 to MCx control bypass switch units BSU1 to BSUx and execute the above-mentioned bypass control or cutoff control. Also, when there are changes in the information received from the cell monitoring unit or various sensors and the information estimated by the module controllers MC1 to MCx themselves, the module controllers MC1 to MCx execute exception control not according to the instructions from the upper controller as necessary.

[0119] The module controllers MC1 to MCx send an instruction to execute cell balancing to the cell monitoring unit for the storage batteries B1 to Bx.

[0120] Figure 10 is a flowchart for explaining the processing of module controllers MC1 to MCx. The processing shown in this flowchart starts when the power storage system 1 is operated and proceeds to step S71, and steps S72 to S82 are repeated while the power storage system 1 is operating.

[0121] In step S71, the module controllers MC1 to MCx initialize various parameters. Next, in step S72, the module controllers MC1 to MCx receive battery state information from the cell monitoring unit or various sensors. Next, in step S73, the module controllers MC1 to MCx acquire information about the state of the module compensator (hereinafter referred to as module compensator state information). Examples of the state of the module compensator include the ambient temperature, current, voltage of the storage batteries B1 to Bx, and the states of the bypass switch units BSU1 to BSUx.

[0122] Next, in step S74, the module controllers MC1 to MCx estimate the states (such as SOH) of the storage batteries B1 to Bx based on the information received in steps S72 and S73. Next, in step S75, the module controllers MC1 to MCx determine the presence or absence of abnormalities in the storage batteries B1 to Bx based on the information obtained in steps S72 to S74. The module controllers MC1 to MCx determine the presence or absence of abnormalities in the storage batteries B1 to Bx, for example, by comparing various detected values and estimated values acquired in steps S72 to S75 with threshold values.

[0123] Next, in step S76, the module controllers MC1 to MCx transmit, to the string controllers SC1 to SCx, the information necessary for the processing of higher-level controllers such as the string controllers SC1 to SCx among the information obtained in steps S72 to S75. Next, in step S77, the module controllers MC1 to MCx receive the instruction information transmitted from the string controllers SC1 to SCx. Here, the string controllers SC1 to SCx determine instructions (such as bypass control instructions and cutoff control instructions) corresponding to the storage batteries B1 to Bx based on the information received from the module controllers MC1 to MCx in step S76, and transmit the instruction information to the module controllers MC1 to MCx in step S77.

[0124] Next, in step S78, the module controllers MC1 to MCx compare the instruction information received in step S77 with the instruction information received last time, and determine whether control of the bypass switch units BSU1 to BSUx is necessary. Also, in step S78, the module controllers MC1 to MCx determine whether there has been a change in the information acquired in steps S72 to S75 and whether exception control (control not based on instructions from higher-level controllers) is necessary. If any of the determinations in step S78 results in an affirmative determination, the process proceeds to step S79; if all of the determinations in step S78 result in negative determinations, the process proceeds to step S72.

[0125] In step S79, the module controllers MC1 to MCx determine whether the instruction information received from the string controllers SC1 to SCx in step S77 includes a bypass control instruction or a cutoff control instruction. If the bypass control instruction is included, the process proceeds to step S80; if the cutoff control instruction is included, the process proceeds to step S81.

[0126] In step S80, the module controllers MC1 to MCx control the bypass switch units BSU1 to BSUx by a predetermined control method to bypass the target storage batteries B1 to Bx (switch S1: connected, switch S2: cutoff). On the other hand, in step S81, the module controllers MC1 to MCx set the switches S1 and S2 of the target bypass switch units BSU1 to BSUx to the cutoff state.

[0127] The process proceeds from step S80 to step S82. In step S82, the module controllers MC1 to MCx perform cell balancing of the storage batteries B1 to Bx to equalize the cell voltages of the storage batteries B1 to Bx. The process proceeds from steps S81 and S82 to step S72, and steps S72 to S82 are repeated during the operation of the power storage system 1.

[0128] As described above, the battery control device 2 of the present embodiment includes a plurality of first control devices 21 provided for each of the strings ST1 to STx, and a second control device 22 that communicates with the plurality of first control devices 21 and a host server 7 outside the power storage system 1 (see FIG. 4). The first control device 21 acquires string state information from various sensors and the like and transmits it to the second control device 22. The second control device 22 calculates charge / discharge power instruction values to be assigned to the plurality of strings ST1 to STx based on the charge / discharge power (or current, the same hereinafter) instruction value of the power storage system 1 received from the host server 7 and the plurality of string state information received from the plurality of first control devices 21, and transmits them to the first control device 21. The first control device 21 controls compensators (string compensator 5 and module compensator) of the strings ST1 to STx, such as bypass switch units BSU1 to BSUx, according to the charge / discharge power instruction values of the strings ST1 to STx received from the second control device 22.

[0129] As a result, in a large-scale power storage system 1 including a large number of strings ST1 to STx, an even larger number of storage batteries B1 to Bx, and an even larger number of compensators such as a large number of bypass switch units BSU1 to BSUx, it is possible to manage the power storage amounts of the large number of strings ST1 to STx and the even larger number of storage batteries B1 to Bx. Therefore, charge / discharge control of the large-scale power storage system 1 can be executed according to the request of DR. On the other hand, by configuring the battery control device 2 with a second control device 22 at the upper layer that processes instructions from the host server 7 outside the power storage system 1 and the display input device 8, and a first control device 21 at the lower layer that is in charge of state detection of each string ST1 to STx and control of compensators, it is possible to avoid complication of control in the power storage system 1 and appropriately suppress the processing load of the battery control device 2.

[0130] Also, in the battery control device 2 of the present embodiment, the second control device 22 transmits the instruction information input from the display input device 8 provided in the power storage system 1 to the first control device 21, and the first control device 21 controls the auxiliary devices of the strings ST1 to STx according to the instruction information received from the second control device 22. That is, the second control device 22 at the upper layer executes the reception process of the instruction information input by an operator or the like using the display input device 8, and the first control device 21 at the lower layer executes the control of the auxiliary devices of the strings ST1 to STx according to the instruction information. Thereby, while appropriately suppressing the processing load of the battery control device 2, various operation modes according to the instructions of an operator or the like, such as maintenance / stop mode, state estimation mode, charge / discharge mode, can be smoothly executed.

[0131] Also, in the battery control device 2 of the present embodiment, the second control device 22 generates a state estimation instruction for the strings ST1 to STx according to the information about the states of the strings ST1 to STx received from the first control device 21 and transmits it to the first control device 21. The first control device 21 controls the auxiliary devices of the strings ST1 to STx according to the state estimation instruction information received from the second control device 22. Thereby, while appropriately suppressing the processing load of the battery control device 2, the state estimation mode can be executed at an appropriate timing.

[0132] Also, in the battery control device 2 of the present embodiment, either the first control device 21 or the second control device 22 estimates the states of the strings ST1 to STx. The second control device 22 calculates the charge / discharge power instruction values of the strings ST1 to STx based on the detection information about the states of the strings ST1 to STx detected by various sensors of the strings ST1 to STx and the estimation information about the states of the strings ST1 to STx estimated by the first control device 21 or the second control device 22. Thereby, while appropriately suppressing the processing load of the battery control device 2, the charge / discharge control of each of the strings ST1 to STx can be executed.

[0133] Also, in the battery control device 2 of the present embodiment, either the first control device 21 or the second control device 22 determines the presence or absence of abnormalities in the strings ST1 to STx based on the above detection information and estimation information and the string compensator state information. Here, since the string compensator state information is acquired by the first control device 21 at the lower layer, it is possible to execute the abnormality determination of the strings ST1 to STx while suppressing the processing load of the second control device 22.

[0134] Also, in the battery control device 2 of the present embodiment, the first control device 21 includes a plurality of module controllers MC1 to MCx provided for each of the modules M1 to Mx, and string controllers SC1 to SCx provided for each of the strings ST1 to STx. The module controllers MC1 to MCx acquire battery state information from various sensors and transmit it to the string controllers SC1 to SCx. The string controllers SC1 to SCx generate bypass control instruction information according to the battery state information received from the module controllers MC1 to MCx and the charge and discharge power instruction values of the strings ST1 to STx received from the second control device 22, and transmit it to the module controllers MC1 to MCx. That is, the module controllers MC1 to MCx at the lower layer are responsible for acquiring the battery state information and controlling the compensators of the modules M1 to Mx such as the bypass switch units BSU1 to BSUx. On the other hand, the string controllers SC1 to SCx at the upper layer are responsible for generating bypass control instruction information such as the above bypass control instructions and cutoff control instructions. Thereby, it is possible to execute the charge and discharge control of the strings ST1 to STx while appropriately suppressing the processing load of the first control device 21.

[0135] In addition, in the battery control device 2 of the present embodiment, the second control device 22 includes a string system controller SSC provided for each string system 10 and a power storage system controller PSC provided corresponding to the hierarchy of the power storage system 1. The string system controller SSC communicates with the first control device 21 and the power storage system controller PSC to control the string system compensator 4. On the other hand, the power storage system controller PSC communicates with the string system controller SSC and the upper server 7, and transmits the instruction information input from the display input device 8 to the string system controller SSC. Further, the power storage system controller PSC controls the power storage system compensator 3 provided in the hierarchy of the power storage system 1. The string system controller SSC transmits the instruction information received from the power storage system controller PSC to the first control device 21. That is, the power storage system controller PSC in the upper hierarchy is responsible for the processing of controlling the compensators in the hierarchy of the power storage system 1 and receiving the instruction information. On the other hand, the string system controller SSC in the lower hierarchy is responsible for the processing of controlling the compensators in the hierarchy of the string system 10 and transmitting the instruction information. Thereby, while appropriately suppressing the processing load of the second control device 22, control according to the instruction information of the strings ST1 to STx can be executed.

[0136] 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 technologies may be combined as appropriate.

[0137] For example, in the above-described embodiment, the first control device 21 is composed of the string controller SC1 and the module controllers MC1 to MCx, but the first control device 21 may be composed of a single controller. Further, in the above-described embodiment, the second control device 22 is composed of the power storage system controller PSC and the string system controller SSC, but the second control device 22 may be composed of a single controller.

Explanation of reference numerals

[0138] 1: Energy Storage System 2: Battery Control Device 3: Energy Storage System Compensator (Compensators) 4: String System Compensator (Compensators) 5: String Compensator (Compensators for Battery String, String Compensators) 7: Upper Server (System outside the Energy Storage System) 8: Display Input Device (Instruction Input Section) 10: String System 11: String Cut-off Switch (Compensators for Battery String, String Compensators) 12: Voltage Sensor (State Detection Section, Compensators for Battery String) 13: Current Sensor (State Detection Section, Compensators for Battery String, String Compensators) 14: Voltage Sensor (State Detection Section, Compensators for Battery String, String Compensators) 21: First Control Device (First Control Section) 22: Second Control Device (Second Control Section) B1~Bx: Batteries BSU1~BSUx: Bypass Switch Unit (Bypass Circuit, Compensators for Battery String) M1~Mx: Modules MC1~MCx: Module Controllers (Module Control Sections) PC1~PCx: Power Converters (Compensators for Battery String, String Compensators) PSC: Energy Storage System Controller (Energy Storage System Control Section) ST1~STx: Strings (Battery Strings) SC1~SCx: String Controllers (String Control Sections) SSC: String System Controller (String System Control Section)

Claims

1. A battery control device for controlling a power storage system including a plurality of battery strings connected in parallel, each battery string including a plurality of batteries connected in series, a plurality of bypass circuits provided for each battery to switch the battery between a bypass state and a connected state, and a power converter for converting input / output power of the battery string, a plurality of first control units provided for each battery string to control accessories of the battery string including the power converter and the bypass circuits, and a second control unit for communicating with a system outside the power storage system and the plurality of first control units, wherein the first control unit acquires information about the state of the battery string and transmits it to the second control unit, the second control unit calculates an instruction value of charge / discharge power or charge / discharge current to be assigned to each of the plurality of battery strings based on an instruction value of charge / discharge power or charge / discharge current of the power storage system received from a system outside the power storage system and information about the states of the plurality of battery strings received from the plurality of first control units, and transmits the calculated instruction value to the first control unit, and the first control unit controls accessories of the battery string according to the instruction value of charge / discharge power or charge / discharge current of the battery string received from the second control unit.

2. The second control unit transmits instruction information input from an instruction input unit provided in the power storage system to the first control unit, and the first control unit controls accessories of the battery string according to the instruction information received from the second control unit. The battery control device according to claim 1.

3. The instruction information is maintenance instruction information for instructing maintenance of the battery string, and the first control unit controls accessories of the battery string according to the maintenance instruction information received from the second control unit. The battery control device according to claim 2.

4. The second control unit generates state estimation instruction information for instructing state estimation of the battery string according to the information about the state of the battery string received from the first control unit, and transmits the generated state estimation instruction information to the first control unit, and the first control unit controls accessories of the battery string according to the state estimation instruction information received from the second control unit. The battery control device according to claim 1 or 2.

5. The instruction information is state estimation instruction information for instructing state estimation of the battery string, The battery control device according to claim 2, wherein the first control unit controls auxiliary devices of the battery string according to the state estimation instruction information received from the second control unit.

6. The instruction information is charge / discharge instruction information for instructing charge / discharge of the battery string, The battery control device according to claim 2, wherein the first control unit controls auxiliary devices of the battery string according to the charge / discharge instruction information received from the second control unit.

7. The information about the state of the battery string includes detection information detected by a state detection unit included in the battery string and estimation information estimated by the first control unit or the second control unit based on the detection information. The battery control device according to claim 1 or 2.

8. The information about the state of the battery string includes information about the state of auxiliary devices of the battery string acquired by the first control unit, The battery control device according to claim 6, wherein the first control unit or the second control unit determines the presence or absence of an abnormality in the battery string based on the information about the state of the battery string.

9. The battery string, A plurality of modules including the battery and the bypass circuit, String auxiliary devices including the power converter, Comprising, The first control unit, A plurality of module control units provided for each module and controlling the bypass circuit, A string control unit provided for each battery string, communicating with the module control unit and the second control unit, and controlling the string auxiliary devices, Comprising, The module control unit acquires information about the state of the battery and transmits it to the string control unit, The string control unit generates bypass control instruction information for controlling the bypass circuit according to the information about the state of the battery received from the module control unit and the instruction value of the charge / discharge power or charge / discharge current of the battery string received from the second control unit, transmits it to the module control unit, and controls the power converter, The battery control device according to claim 1 or 2, wherein the module control unit controls the bypass circuit according to the bypass control instruction information received from the string control unit.

10. The power storage system, Comprising a single or a plurality of string systems each comprising a plurality of said battery strings, Said second control unit Is provided for each of said string systems, communicates with said first control unit, and is a string system control unit that controls accessories included in said string system, Communicates between said string system control unit and a system outside said power storage system, transmits said instruction information input from said instruction input unit to said string system control unit, and controls accessories different from said battery strings and the accessories included in said string system, i.e., a power storage system control unit Comprises The battery control device according to claim 2, wherein said string system control unit transmits said instruction information received from said power storage system control unit to said first control unit.

11. A plurality of battery strings connected in parallel, A battery control device Comprises Said battery strings A plurality of batteries connected in series, A plurality of bypass circuits provided for each of said batteries and switching said batteries between a bypass state and a connected state, A power converter that converts the input / output power of said battery string A power storage system comprising Said battery control device Comprises a plurality of first control units provided for each of said battery strings and controlling accessories of said battery strings including said power converter and said bypass circuits, A second control unit that communicates between a plurality of said first control units and a system outside said power storage system Comprises Said first control unit acquires information about the state of said battery string and transmits it to said second control unit, Based on the instruction value of the charge / discharge power or charge / discharge current of said power storage system received from a system outside said power storage system and the information about the states of a plurality of said battery strings received from a plurality of said first control units, said second control unit calculates the instruction value of the charge / discharge power or charge / discharge current to be assigned to each of a plurality of said battery strings and transmits it to said first control unit, A power storage system in which said first control unit controls the accessories of said battery string according to the instruction value of the charge / discharge power or charge / discharge current of said battery string received from said second control unit.

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