JP2023176283A - Power source system - Google Patents

Abstract

To release a power storage device at a proper timing in response to a request from a controller which receives power supply from the power storage device.SOLUTION: A power source system includes: a power storage device to be fixed for supplying power to an electric load; a first controller for receiving power supply from the power storage device; a power conversion circuit located between the electric load and the power storage device and not located between the power storage device and the first controller; and a second controller for controlling the power conversion circuit. The power conversion circuit includes at least one switch for switching an electric path connecting an electric load and the power storage device between a connection state and a cut-off state. The first controller sends a cut-off request signal for requesting release of the power storage device to the second controller when a predetermined first condition is satisfied. The second controller controls at least one switch to make the power storage device in an open circuit state when a second condition including reception of the cut-off request signal is satisfied.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a technique for appropriately managing a stationary power storage device.

Japanese Unexamined Patent Publication No. 2018-19575 (Patent Document 1) discloses a power supply system including a stationary power storage device and a power conversion circuit.

Japanese Patent Application Publication No. 2018-19575

Stationary power storage devices are expected to continue to be used. Therefore, the stationary power storage device is basically in a closed circuit state. However, when maintenance of the power storage device is performed, the power storage device is opened. That is, maintenance is performed with the power storage device in an open state (open circuit state). In general, maintenance of a stationary power storage device is considered to be performed when the control unit of the power supply system is stopped, that is, when power is not supplied to each control device included in the power supply system. When the user does not use the power system, the user stops the control unit of the power system to put the power system into a non-operating state. As a result, the power storage device becomes de-energized, and it becomes possible to perform processing related to maintenance of the power storage device. Examples of maintenance-related processing include correction of various sensors for acquiring information about the power storage device, acquisition of OCV (Open Circuit Voltage) of the power storage device, and the like.

However, once the control unit of the power supply system is brought to a halted state, it takes time to return to a controllable state, which may impair user convenience. Furthermore, if the control unit is brought to a halt state every time maintenance is performed, it becomes difficult for the control unit of the power supply system to appropriately manage the timing of opening the power storage device (and, by extension, the timing of maintenance). However, from the viewpoint of cost, it is not desirable to add a new power storage device (power storage device for the control section) to maintain the control section of the power supply system in an operating state during maintenance of the power storage device.

Furthermore, in order to continue using a stationary power storage device over a long period of time, it is desirable to perform maintenance on the power storage device with sufficient frequency. In the power supply system described in Patent Document 1, the power storage device is not opened for maintenance of the power storage device, so there is a possibility that maintenance of the power storage device is not performed frequently enough.

The present disclosure has been made to solve the above problems, and the purpose is to provide a power supply that can open a power storage device at an appropriate timing in response to a request from a control device that receives power from the power storage device. The goal is to provide a system.

A power supply system according to the present disclosure includes a stationary power storage device that supplies power to an electric load, a first control device that receives power from the power storage device, and is located between the electric load and the power storage device, and The power conversion circuit includes a power conversion circuit that is not located between the power storage device and the first control device, and a second control device that controls the power conversion circuit. The power conversion circuit includes at least one switch that switches between a connected state and a disconnected state of an electric line connecting an electric load and a power storage device. The first control device is configured to transmit a cutoff request signal requesting to open the power storage device to the second control device when a predetermined first condition is satisfied. The second control device is configured to control at least one switch so that the power storage device enters an open circuit state when a second condition including receiving the cutoff request signal is satisfied.

The first control device can request the second control device to open the power storage device by transmitting a cutoff request signal to the second control device. The first control device can request the second control device to open the power storage device at an appropriate timing by monitoring whether the first condition is met.

Further, when the second condition is satisfied, the power storage device is disconnected from the electric load circuit by the switch of the power conversion circuit, and the power storage device becomes an open circuit state. The second condition may be satisfied only when the second control device receives the cutoff request signal from the first control device, or may be satisfied when other requirements are further satisfied. The power conversion circuit is not located between the power storage device and the control device, so even if the electrical path connecting the electrical load and the power storage device is cut off by a switch, the power path connecting the power storage device and the control device remains connected. be done. Therefore, even if the power storage device is in an open circuit state, the first control device can receive power from the power storage device. In the above power supply system, control can be executed to switch the power storage device between open and closed states (open circuit state/closed circuit state) while maintaining the first control device in the operating state. Since the first control device that manages the opening timing of the power storage device is maintained in an operating state, the power storage device can be easily opened at an appropriate timing.

The first control device can operate even while the power storage device is in an open circuit state. The first control device may acquire information regarding the power supply system (e.g., the power storage device) while the power storage device is in the open circuit state, and the second control device may return the power storage device to the closed circuit state. may be requested from the device.

The first condition may include that a predetermined period of time has passed since the last time maintenance was performed. The first control device may be configured to perform processing related to maintenance of the power storage device while the power storage device is in an open circuit state when the second condition is satisfied.

According to the above configuration, the first control device can request the second control device to open the power storage device when a predetermined period of time has passed since the last time maintenance was performed. Further, the first control device can automatically execute maintenance-related processing. Therefore, maintenance of the power storage device can be easily performed with sufficient frequency.

Note that examples of processing related to maintenance include acquisition of OCV (Open Circuit Voltage) of the power storage device, equalization of cell voltages, etc. described below.

In any of the power supply systems described above, the power storage device may include an assembled battery including a plurality of cells electrically connected to each other. The first condition may include that the degree of variation in cell voltage in the assembled battery exceeds a predetermined level. The first control device may be configured to equalize the cell voltages in the assembled battery while the power storage device is in an open circuit state when the second condition is satisfied.

According to the above configuration, when the degree of variation in cell voltage in the assembled battery becomes large, the first control device can request the second control device to open the power storage device. Furthermore, equalization of cell voltages can be automatically performed by the first control device. Therefore, it is possible to suppress variations in cell voltage in the assembled battery from becoming excessively large.

Any of the power supply systems described above further includes at least one relay disposed between the power storage device and the first control device and between the power storage device and the power conversion circuit. Good too. The first control device may be configured to receive power from at least one of an external power source and a power generation device. After transmitting the cutoff request signal to the second control device, the first control device activates at least one relay so that the power storage device enters an open circuit state when a third condition including receiving permission from the user is satisfied. may be configured to control.

In the above configuration, the first control device can receive power not only from the power storage device but also from at least one of the external power source and the power generation device. Further, the first control device can open the power storage device using at least one relay located between the power storage device and the power conversion circuit. When the power storage device is opened by the relay, the voltage of the power storage device is no longer applied to the power conversion circuit, and deterioration of the power conversion circuit is suppressed.

However, in the power supply system described above, the first control device cannot always receive power from the external power supply or power generation device. It is also conceivable that an abnormality occurs in the external power supply and the power supply from the external power supply to the first control device is stopped (power outage). There is also a possibility that the power generation device cannot generate enough power. Therefore, in the above configuration, the condition (third condition) for opening the power storage device by the relay includes receiving permission from the user. After checking the status of the external power source and the power generation device, the user can permit the first control device to open the power storage device using the relay. This prevents the first control device from losing power and stopping.

In any of the power supply systems described above, the second control device controls the power conversion circuit so that when a predetermined fourth condition is satisfied, the power storage device enters an open circuit state regardless of whether or not a cutoff request signal is received. After controlling the at least one switch, the power storage device may be configured to transmit a signal indicating that the power storage device is in an open circuit state to the first control device.

In order to perform sufficient maintenance on the power storage device, it is desirable to put the power storage device into an open circuit state with sufficient frequency. Further, even if the power storage device is placed in an open circuit state in a situation where the power storage device is in a standby state (a state in which neither charging nor discharging is performed), it is considered that the user's convenience will not be impaired. Therefore, in the above power supply system, when the fourth condition is satisfied, the second control device opens the power storage device regardless of whether or not a cutoff request signal is received (that is, whether there is a request from the first control device). Put into circuit state. By setting the fourth condition so that it holds true in situations where there is a high possibility that the power storage device will be in standby mode, it is possible to achieve both high user convenience and sufficient maintenance for stationary power storage devices. Become.

Further, in the above power supply system, after the second control device places the power storage device in an open circuit state, the second control device transmits a signal indicating that the power storage device has entered the open circuit state to the first control device. By receiving the signal from the second control device, the first control device can easily manage the opening timing of the power storage device.

According to the present disclosure, it is possible to provide a power supply system that can open a power storage device at an appropriate timing in response to a request from a control device that receives power from the power storage device.

FIG. 1 is a diagram for explaining an overview of a power supply system according to an embodiment of the present disclosure. 1 is a flowchart illustrating a first example of a method for switching the open/close state of a power storage device according to an embodiment of the present disclosure. 3 is a time chart showing an example of state transition of the power supply system in the method shown in FIG. 2. FIG. 12 is a flowchart illustrating a second example of a method for switching the open/closed state of the power storage device according to the embodiment of the present disclosure. 5 is a time chart showing an example of state transition of the power supply system in the method shown in FIG. 4. FIG. 12 is a flowchart illustrating a third example of a method for switching the open/close state of a power storage device according to an embodiment of the present disclosure.

Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a diagram for explaining an overview of a power supply system according to an embodiment of the present disclosure. Referring to FIG. 1, the power supply system according to this embodiment is applied to a building 100. In this embodiment, building 100 is a residence (eg, a user's home). However, the building 100 is not limited to this, and may be another building (a factory, a commercial facility, etc.).

The power supply system of the building 100 includes a control device 112, a control unit 122, a control device 250, and various sensors. Each of the control device 112, the control unit 122, and the control device 250 corresponds to a control unit of the power supply system, receives detection results from various sensors, and controls the power supply equipment of the building 100. Further, the control unit of the power supply system performs wireless communication with the mobile terminal 500.

As each of the control device 112, the control unit 122, and the control device 250, a computer including a processor, a RAM (Random Access Memory), a storage device, a timer (timekeeping function), and a communication I/F (interface) can be adopted. Furthermore, the mobile terminal 500 also incorporates a computer having a similar configuration. As the processor, for example, a CPU (Central Processing Unit) can be used. The storage device is configured to be able to store stored information. The storage device may include, for example, a ROM (Read Only Memory) and a rewritable nonvolatile memory. In each computer, various processes (see, for example, FIGS. 2 to 6) are executed by a processor executing a program stored in a storage device. However, these various processes are not limited to execution by software, but can also be executed by dedicated hardware (electronic circuits).

Mobile terminal 500 is carried by a user. In this embodiment, a smartphone equipped with a touch panel display is employed as the mobile terminal 500. Application software for using the power supply system is installed in the mobile terminal 500. However, the present invention is not limited to this, and any mobile terminal 500 can be used as the mobile terminal 500, such as a laptop, a tablet terminal, a wearable device (for example, a smart watch, smart glasses), or an electronic key. .

The control device 112, the control unit 122, and the control device 250 are connected via, for example, a bus (not shown) and communicate with each other by wire. In this embodiment, mobile terminal 500 and control device 112 communicate directly, but mobile terminal 500 and control device 250 do not communicate directly. Information is exchanged between the mobile terminal 500 and the control device 250 via the control device 112. This improves the confidentiality of the information security of the control device 250. However, the present invention is not limited to this, and the mobile terminal 500 may be configured to be able to directly communicate with each of the control device 112, the control unit 122, and the control device 250.

In this embodiment, a control device 112, a control unit 122, and a control device 250 are housed in a power conversion unit 110, a PCS 120, and a power storage pack 200, respectively, which will be described below.

The power supply system of the building 100 includes a power conversion unit 110, a PCS (Power Conditioning System) 120, and a distribution board 130. The building 100 is provided with a stationary power storage pack 200 and a power generation device 300. Power storage pack 200 is electrically connected to power conversion unit 110. Power generation device 300 is electrically connected to PCS 120.

Power conversion unit 110 includes a DC/DC converter 111 and a control device 112 that controls DC/DC converter 111.

DC/DC converter 111 is located between electrical load 150 and power storage device 210 and is arranged not to be located between power storage device 210 and control device 250. DC/DC converter 111 includes at least one switch 111a that switches between a connected state and a disconnected state of an electric line connecting electrical load 150 and power storage device 210. Although only one switch 111a is shown in FIG. 1, the number of switches 111a included in the DC/DC converter 111 may be two or more. The DC/DC converter 111 may include four bridge-connected switches 111a. The switch 111a is, for example, a thyristor such as an IGCT (Integrated Gate-Commutated Thyristor). However, the present invention is not limited thereto, and other semiconductor switches such as triacs or transistors (IGBT, MOSFET, bipolar transistor, etc.) can also be employed as the switch 111a.

The DC/DC converter 111 is a bidirectional DC/DC converter that performs power conversion (for example, voltage transformation) in both directions. The DC/DC converter 111 may be a buck-boost chopper bidirectional DC/DC converter. When direct current power (DC) is input from PCS 120 to DC/DC converter 111 , DC/DC converter 111 outputs the converted direct current power (DC) to power storage pack 200 . When DC power (DC) is input from power storage pack 200 to DC/DC converter 111, DC/DC converter 111 outputs the DC power (DC) after power conversion to PCS 120. Note that the DC/DC converter 111 may be an isolated bidirectional DC/DC converter or a non-insulated bidirectional DC/DC converter.

The control device 112 can switch the connection/cutoff of the electric path connecting the circuit on the power storage pack 200 side and the circuit on the PCS 120 side by controlling the open/close state (open state/closed state) of at least one switch 111a. . For example, the DC/DC converter 111 may be configured such that when all the switches 111a are opened, the electrical path connecting the circuit on the power storage pack 200 side and the circuit on the PCS 120 side is cut off. Hereinafter, the control by the control device 112 of at least one switch 111a so that the electrical path connecting the distribution board 130 (electrical load 150) and the power storage device 210 is cut off will be referred to as "gate cutoff".

The PCS 120 is electrically connected to the power grid PG. The power system PG includes a power grid, power generation equipment, and substation equipment. The power grid is constructed by transmission and distribution equipment. The power grid PG supplies power to a predetermined area. Building 100 is located within a predetermined area. The power grid PG supplies AC power (for example, single-phase or three-phase AC power) to the PCS 120.

The PCS 120 includes a circuit section 121 and a control section 122 that controls the circuit section 121. The circuit unit 121 includes various circuits for processing related to power conditioning (for example, power conversion and input/output adjustment). In this embodiment, circuit section 121 includes a DC/DC converter and an AC/DC conversion circuit (inverter). However, the circuit configuration of the circuit section 121 can be changed as appropriate. Electric power is input to the circuit unit 121 from each of the power system PG, the power generation device 300, and the DC/DC converter 111 (on the power storage pack 200 side). Further, the circuit unit 121 outputs power to each of the DC/DC converter 111 and the distribution board 130. The circuit unit 121 converts AC power received from the power grid PG into DC power, and outputs the DC power to the DC/DC converter 111 (on the power storage pack 200 side).

The power generation device 300 generates power using natural energy or fuel, and outputs the generated power to the circuit section 121 of the PCS 120. Power generation device 300 according to this embodiment includes a solar panel installed on the roof of building 100. Solar panels use sunlight to generate electricity. Solar panels are a naturally variable power source whose power generation output fluctuates depending on weather conditions. However, the power generation device 300 is not limited to a solar panel, and may include other power generation devices (for example, a wind power generation device or a hydroelectric power generation device).

The distribution board 130 receives power (for example, single-phase or three-phase AC power) from the circuit unit 121 of the PCS 120 . The circuit unit 121 converts the power received from each of the power system PG, the power generation device 300, and the DC/DC converter 111 into power suitable for the distribution board 130, and outputs the converted power to the distribution board 130. do. Distribution board 130 is electrically connected to electric load 150. Electrical load 150 receives power from distribution board 130 . Electric load 150 may be directly connected to distribution board 130. Alternatively, the electrical load 150 may be electrically connected to the distribution board 130 via an outlet (not shown) provided in the building 100. Electrical loads 150 may include lighting fixtures. The electrical loads 150 may include household electrical appliances used indoors in the building 100 (eg, air conditioners, cooking appliances, information devices, refrigerators, or washing machines). The electric load 150 may include electric vehicle supply equipment installed outside the building 100.

Power storage pack 200 includes a power storage device 210, a BMS (Battery Management System) 210a, an SMR (System Main Relay) 220, a power conversion circuit 230, and a control device 250.

Power storage device 210 is a stationary power storage device that supplies power to electric load 150. Power storage device 210 is configured to include, for example, a secondary battery. In this embodiment, a battery pack including a plurality of lithium ion secondary batteries is employed as power storage device 210. A battery pack includes a plurality of secondary batteries (generally also referred to as "cells") that are electrically connected to each other. Note that the secondary battery may be a liquid type secondary battery or an all-solid secondary battery.

The power storage device 210 is provided with a BMS (Battery Management System) 210a that monitors the state of the power storage device 210. BMS 210a includes various sensors that detect the state (for example, voltage, current, and temperature) of power storage device 210, and a monitoring IC (integrated circuit) into which detection signals from the various sensors are input. The monitoring IC generates a signal (hereinafter also referred to as a “BMS signal”) indicating the state of power storage device 210 using detection signals from various sensors, and outputs the generated BMS signal to control device 250. In this embodiment, one voltage sensor and one temperature sensor are provided for each cell configuring power storage device 210 (battery assembly). However, the present invention is not limited to this, and one voltage sensor and one temperature sensor may be provided for each of a plurality of cells, or only one voltage sensor and one temperature sensor may be provided for each assembled battery.

In this embodiment, the monitoring IC further has a SOC (State of Charge) estimation function and an SOH (State of Health) estimation function. Control device 250 can acquire the state of power storage device 210 (eg, temperature, current, voltage, SOC, and SOH) based on the BMS signal. The SOC indicates the remaining amount of stored power, and is, for example, the ratio of the current amount of stored power to the amount of stored power in a fully charged state, expressed as 0 to 100%. SOH indicates the degree of health or deterioration, and is expressed, for example, as the ratio of the current full charge capacity to the initial full charge capacity on a scale of 0 to 100%.

In this embodiment, the monitoring IC further has a cell voltage equalization function. Specifically, a switch (not shown) is provided between adjacent cells in power storage device 210 to connect or disconnect an electric path connecting the cells. These switches are controlled by a monitoring IC. The monitoring IC performs cell voltage equalization by switching each switch between a closed state and an open state.

SMR 220 includes at least one relay that switches connection/disconnection of an electric path connecting power storage device 210 and DC/DC converter 111. In this embodiment, SMR 220 includes a pair of relays (eg, electromagnetic mechanical relays). These relays are located between power storage device 210 and control device 250 and between power storage device 210 and DC/DC converter 111. SMR 220 is controlled by control device 250. The SMR 220 is basically maintained in a closed state (connected state), but is shut off when a predetermined condition is met (see FIG. 6, which will be described later). Note that the number of relays constituting the SMR 220 can be changed as appropriate.

In this embodiment, the control unit 122 of the PCS 120 switches between grid-connected operation and independent operation. While power is being supplied to the PCS 120 from the power grid PG, the control unit 122 puts the building 100 in a grid-connected operation state. In grid-connected operation, power is supplied from the power grid PG to the distribution board 130. During grid-connected operation, the power system PG and the distribution board 130 are electrically connected. On the other hand, if some kind of malfunction occurs in the power system PG and power supply from the power system PG to the distribution board 130 is stopped (power outage), the control unit 122 switches from grid-connected operation to self-sustaining operation. As a result, the building 100 enters a self-sustaining state. In self-sustaining operation, power is not supplied from the power grid PG to the power distribution board 130, and the power storage device 210 supplies power to the power distribution board 130 instead of the power grid PG. During self-sustaining operation, the control unit 122 controls the circuit unit 121 so that the electric path connecting the power system PG and the distribution board 130 is cut off by the PCS 120. Thereby, the power system PG and the distribution board 130 are electrically separated.

Power conversion circuit 230 corresponds to a power supply circuit of control device 250. Power conversion circuit 230 includes a DC/DC converter. For example, the power conversion circuit 230 steps down the input DC power and outputs the stepped down DC power to the control device 250. The power conversion circuit 230 is connected to an electric path branched from between the SMR 220 and the DC/DC converter 111. During interconnected operation, power from the power grid PG is supplied to the power conversion circuit 230 via the PCS 120 and the DC/DC converter 111. During self-sustaining operation, power from power storage device 210 or power generation device 300 is supplied to power conversion circuit 230. The power conversion circuit 230 converts the supplied power into power suitable for operating the control device 250 (for example, about 12 V DC power), and outputs the converted power to the control device 250.

The building 100 may include an EMS (Energy Management System). The power supply system of the building 100 also includes a power meter (for example, a smart meter) that detects the power exchanged between the power system PG and the distribution board 130, and a power meter (for example, a smart meter) that detects the power that is input to the PCS 120 and the power that is output from the PCS 120. The power consumption meter may further include a power meter that detects each of the electric power and the electric power. The detection results from these power meters may be output to the EMS. Using the detection results from these power meters, the EMS calculates the generated power and demanded power of the building 100 during grid-connected operation (corresponding to the sum of the generated power and the power supplied from the power grid PG), and the power demand during isolated operation. The generated power and the demanded power (corresponding to the total of the generated power and the power supplied from the power storage device 210) of the building 100 in 2008 may be acquired, and such data may be recorded over time. The control device 250 may receive information indicating the supply and demand status of the building 100 from the EMS. EMS sends a signal (hereinafter referred to as "PV (Photovoltaic) charging) requesting that the power storage device 210 store the surplus power when the power generated by the power generation device 300 (solar panel) exceeds the demand power and surplus power is generated. A "request signal") may be sent to the controller 112.

The power supply system according to this embodiment can operate in first to third operation modes. The third operation mode is an operation mode that allows external control (for example, charge/discharge control of power storage device 210 by EMS or an external server). In the third operation mode, while the power supply system is receiving a control command from the outside, charging and discharging control of the power storage device 210 by the control unit (control device 112, control unit 122, and control device 250) of the power supply system is prohibited. Ru. On the other hand, in each of the first and second operation modes, the control unit of the power supply system controls charging and discharging of power storage device 210 without allowing external control. In one example, the first mode of operation corresponds to a normal mode, the second mode of operation corresponds to an energy saving mode, and the third mode of operation corresponds to an external control mode.

The user may set one operation mode selected from the first to third operation modes to the control device 112 via the mobile terminal 500. For example, when the user inputs an operation mode to the mobile terminal 500, the mobile terminal 500 may transmit the operation mode to the control device 112, and the operation mode may be set in the control device 112. The power supply system according to this embodiment operates in an operation mode set in the control device 112.

FIG. 2 is a flowchart illustrating a first example of a method for switching the open/closed state of power storage device 210. "S" in the flowchart means a step. A series of processes from S11 to S17 is executed by the control device 112 (power conversion unit 110), and a series of processes from S21 to S23 is executed by the control device 250 (power storage pack 200). The control device 112 monitors the success or failure of the gate cutoff condition by repeatedly executing a series of processes from S11 to S17.

Referring to FIG. 2 together with FIG. 1, in S11, the control device 112 obtains the set operation mode (that is, the current operation mode of the power supply system). As mentioned above, the operating mode is set on the controller 112 by the user.

Subsequently, the control device 112 determines whether a predetermined gate cutoff condition is satisfied in S12. In this embodiment, different gate cutoff conditions are set for each operation mode. That is, the control device 112 obtains the gate cutoff condition corresponding to the operation mode obtained in S11, and determines whether the gate cutoff condition is satisfied.

The gate cutoff condition corresponding to the first operation mode is satisfied when the current time is in a predetermined time period and charging of the power storage device 210 is completed, and is not satisfied when these requirements are not met. . The predetermined time period may be a late night time period (for example, 2:00 to 5:00). Control device 112 may determine that charging of power storage device 210 has been completed when charging of power storage device 210 has been completed normally (that is, when power storage device 210 has been charged to the target SOC). Further, control device 112 determines that charging of power storage device 210 is completed when the SOC of power storage device 210 is equal to or higher than a predetermined first SOC value (for example, an upper limit SOC value indicating full charge of power storage device 210). You can judge.

The gate cutoff condition corresponding to the second operation mode is that the SOC of power storage device 210 is equal to or lower than a predetermined second SOC value (for example, the lower limit SOC value indicating the discharge limit of power storage device 210), and a PV charging request signal is received. It holds true if these requirements are not met, and it does not hold true if these requirements are not met.

The gate cutoff condition corresponding to the third operation mode is satisfied when the control device 112 receives a standby command from the outside (e.g., EMS or server), and is satisfied when the control device 112 does not receive a standby command from the outside. does not hold true. Note that while the control device 112 receives the standby command, the power storage device 210 is maintained in a standby state (a state in which neither charging nor discharging is performed).

If the gate cutoff condition is satisfied (YES in S12), the control device 112 determines in S13 whether a predetermined cutoff prohibition condition is satisfied. The control device 112 determines, for example, that an abnormality has occurred in the power conversion unit 110 (first prohibition condition), that the building 100 is in autonomous operation (second prohibition condition), and that a discharge request has occurred. (third prohibition condition), it is determined whether the cut-off prohibition condition is satisfied or not. In this embodiment, the blocking prohibition condition is satisfied when any one of the first to third prohibiting conditions is satisfied, and the blocking prohibiting condition is not satisfied when none of the first to third prohibiting conditions are satisfied. . The third prohibition condition is satisfied, for example, when a target to which power storage device 210 supplies power (for example, PCS 120 or electric load 150) requests control device 112 to discharge power storage device 210.

In this embodiment, the control device 112 determines whether the fourth condition is satisfied in S12 and S13. In this embodiment, a determination of YES in S12 and NO in S13 means that the fourth condition is satisfied. Furthermore, the determination of NO in S12 and the determination of YES in S13 each mean that the fourth condition is not satisfied.

If the fourth condition is satisfied (YES in S12 and NO in S13), the control device 112 executes gate cutoff in S14. As a result, the electric path connecting power storage pack 200 and PCS 120 is cut off, and power storage device 210 enters an open circuit state (open state). Since no current flows through power storage device 210 in the open state, the current in power storage device 210 in the open state becomes 0A.

Subsequently, in S15, the control device 112 transmits a status signal of “gate blocking” to the control device 250. The status signal “gate cut off” corresponds to a signal indicating that power storage device 210 is in an open circuit state. Thereafter, the control device 112 determines whether a cutoff release request has occurred in S16. Until a disconnection release request is issued (NO in S16), S14 to S16 are repeated. Details of S16 will be described later.

When the control device 250 receives the status signal “Gate is being shut off”, it starts a series of processes from S21 to S23. In S21, control device 250 executes processing related to maintenance of released power storage device 210. Specifically, the control device 250 executes processes related to the first item and second item described below as processes related to maintenance. A monitoring IC included in the BMS 210a may execute processing related to the first item and the second item in accordance with instructions from the control device 250.

The first item is self-diagnosis of the monitoring IC included in the BMS 210a. Specifically, the monitoring IC acquires the OCV of the power storage device 210 from the voltage sensor included in the BMS 210a when the power storage device 210 is in a non-energized state (current 0 A), and outputs the acquired OCV to the control device 250. do. The monitoring IC self-diagnoses whether it can operate normally based on whether or not OCV acquisition was performed normally. The control device 250 associates the OCV received from the monitoring IC with the acquisition time and stores it in the storage device.

The second item is equalization of cell voltages in power storage device 210. Specifically, the monitoring IC executes opening/closing control of switches provided between adjacent cells of power storage device 210 so that the cell voltages in power storage device 210 are equalized.

In S22, control device 250 determines whether maintenance of power storage device 210 is completed. The control device 250 determines whether or not each item is completed. When any item is completed, the control device 250 stores information obtained during maintenance (for example, information regarding an abnormality) in the storage device along with the time when that item was completed. The control device 250 has a completion flag for each item, and when any item is completed, turns on the corresponding completion flag. When the completion flags of all items are turned ON during gate shutoff (that is, when all items are completed), the control device 250 transmits a maintenance completion signal to the control device 112. Then, YES is determined in S22. On the other hand, if any item is not completed, NO is determined in S22, and the process proceeds to S23.

The control device 250 determines whether the gate is being shut off in S23. The control device 250 determines YES in S23 while receiving the status signal "gate cut off" from the control device 112, and determines NO in S23 when the status signal is no longer received. While the determination is YES in S23 and NO in S22, S21 to S23 are repeated. Thereby, maintenance of power storage device 210 (S21) is continued. On the other hand, when the maintenance of power storage device 210 is completed (YES in S22) or the gate cutoff is canceled (NO in S23), control device 250 ends the series of processes from S21 to S23.

During maintenance of power storage device 210, control device 250 measures the elapsed time from the start of the maintenance. This time may be clocked by a counter. Control device 112 may increment the counter during maintenance of power storage device 210.

When the control device 250 detects an abnormality (abnormal voltage deviation, abnormal operation of the monitoring IC, etc.) during maintenance of the power storage device 210, the control device 250 records the details of the detected abnormality and sends a signal indicating the occurrence of the abnormality (hereinafter referred to as " (also referred to as "abnormal signal") may be transmitted. Control device 250 may transmit an abnormality signal to mobile terminal 500. When mobile terminal 500 receives the abnormality signal, it may display a message indicating that an abnormality has occurred. The abnormality signal may include information indicating the type of abnormality (for example, a code indicating whether the abnormality was detected in the first item or the second item).

The control device 112 determines whether or not it has received the maintenance completion signal from the control device 250 in S16 described above. When the control device 112 receives the maintenance completion signal, it determines that a disconnection release request has occurred. Further, in S16, the control device 112 further determines whether the above-mentioned shutoff prohibition condition (see S13) is satisfied. The control device 112 also determines that a shutdown cancellation request has occurred when the shutdown prohibition condition is satisfied. If a request to release the gate is issued (YES in S16), the control device 112 releases the gate shutdown in S17. As a result, the electric path connecting power storage pack 200 and PCS 120 is connected, and power storage device 210 enters a closed circuit state. By executing the process in S17, the series of processes in S11 to S17 is completed, and the process returns to the first step (S11).

FIG. 3 is a time chart showing an example of state transition of the power supply system that executes the control shown in FIG. In FIG. 3, lines L11, L12, L13, and L14 indicate whether or not the gate is shut off (blocked/released), a counter that indicates the elapsed time from the start of maintenance, a completion flag for the first item, and a completion flag for the second item, respectively. It shows. Note that "t" in the time chart means timing.

Table M shows the required time and recommended frequency for each of the first and second items. Table M is stored in the storage device of control device 112. In FIG. 3, "Th1" corresponds to a counter value corresponding to the time required for the first item (for example, 30 seconds). “Th2” corresponds to a counter value corresponding to the time required for the second item (for example, 30 minutes to 3 hours). The time required for the second item becomes longer as the degree of variation in cell voltage in power storage device 210 (battery assembly) increases. The control device 250 detects the degree of variation in cell voltage and determines the corresponding time required for the second item. The degree of variation can be expressed by a well-known variation index. For example, the degree of variation in cell voltage may be expressed as the difference between the highest cell voltage and the lowest cell voltage, or may be expressed as the dispersion, standard deviation, or coefficient of variation of the cell voltage.

Referring to FIG. 3 together with FIG. 1, at t11, gate cutoff is not performed (line L11). Thereafter, when the gate is shut off (S14 in FIG. 2) at t12, maintenance of power storage device 210 (and thus incrementing of the counter) is started (line L12). While the gate is shut off, the counter is incremented, and the counter value reaches Th1 at t13. As a result, the completion flag of the first item is turned ON (line L13). After that, gate blocking is canceled at t14 (S17 in FIG. 2). At t14, the counter value (line L12) has not reached Th2. This means that the second item is not completed (line L14).

Gate cutoff is performed again at t15 (line L11). Then, at t16, the first item is completed, and the completion flag of the first item is turned ON (line L13). Furthermore, the counter value reaches Th2 at t17 (line L12). As a result, the completion flag of the second item is turned ON (line L14). Since all items have been completed, control device 250 sends a maintenance completion signal to control device 112. In response to receiving the maintenance completion signal, the control device 112 releases the gate cutoff at t18 (line L11).

FIG. 4 is a flowchart illustrating a second example of a method for switching the open/closed state of power storage device 210. A series of processes from S31 to S36 is executed by the control device 250, and a series of processes from S41 to S46 is executed by the control device 112. Each control device may start a series of processes when it is started up and end it when it is stopped (shutdown). Alternatively, each control device may start a series of processes at a predetermined start time and end them at a predetermined end time every day.

Referring to FIG. 4 together with FIG. 1, in S31, control device 250 determines whether a predetermined first shutoff request condition is satisfied. If the first cutoff request condition is satisfied (YES in S31), control device 250 sends a first cutoff request signal requesting gate cutoff (opening of power storage device 210) to control device 112 in S32. Send.

In this embodiment, the first shutoff request condition is satisfied when a predetermined period of time has elapsed from the timing at which maintenance was most recently performed (the time when maintenance was previously performed). The control device 250 transmits the first shutoff request signal so that the maintenance frequency approaches the recommended frequency. The control device 250 determines whether the first shutoff request condition is satisfied for each maintenance item. The control device 250 may determine the predetermined time for each item in accordance with the recommended frequency shown in Table M (FIG. 3). In this embodiment, regarding the first item, the first cutoff request condition is satisfied when one day has passed since the last execution. Regarding the second item, the first cutoff request condition is satisfied when one month has passed since the last execution. If the first cutoff request condition is satisfied in any item, YES is determined in S31, and the process proceeds to S32. The first cutoff requirement condition in S31 corresponds to an example of a "first condition" according to the present disclosure.

On the other hand, in S41, the control device 112 determines whether a request to shut off the gate has been received from the control device 250. When the control device 112 receives the first shutoff request signal (YES in S41), it determines in S42 whether the current time is within a predetermined time period. In this embodiment, the predetermined time period is a late night time period (for example, 2:00 to 5:00).

If the current time is within the predetermined time zone (YES in S42), the control device 112 executes gate cutoff in S43 in response to a request from the control device 250. In this case, the control device 112 executes the same processes as S14 to S17 in FIG. 2 in S43 to S46, respectively. In the process shown in FIG. 4, a determination of YES in both S41 and S42 means that the second condition is satisfied. On the other hand, if the current time is not within the predetermined time zone (NO in S42), the control device 112 does not execute the gate shutdown even if it receives the first shutdown request signal. In this case, the process returns to S41.

After transmitting the first cutoff request signal (S32), the control device 250 determines in S33 whether or not it has received a “gate cutoff” status signal (S44) from the control device 112. Then, when the control device 250 receives the status signal "gate cut off" (YES in S33), it executes the same processes as S21 to S23 in FIG. 2 in S34 to S36, respectively. However, in S34, only maintenance items for which it was determined in S31 that a predetermined period of time has elapsed since the previous execution are executed.

The control device 250 may continue to transmit the first cutoff request signal even during maintenance, and may stop transmitting the first cutoff request signal when the maintenance is completed. In such a form, the OFF signal of the shutdown request corresponds to the maintenance completion signal.

FIG. 5 is a time chart showing an example of state transition of the power supply system that executes the control shown in FIG. 4. In FIG. 5, lines L21, L22, L23, and L24 respectively indicate the presence or absence of gate shutoff (blocking/cancellation), the presence or absence of a shutoff request, a counter indicating the elapsed time from the start of maintenance, and a completion flag of the second item. There is.

Referring to FIG. 5 together with FIG. 1, at t21, gate cutoff is not performed (line L21). Thereafter, at t22, one month has passed since the last execution of the second item, and the first cutoff request condition is satisfied. When the first cutoff request condition is satisfied, a first cutoff request signal is transmitted from the control device 250 to the control device 112 (line L22, S31, S32 in FIG. 4). Then, gate cutoff is executed at t23 (S43 in FIG. 4). That is, t23 corresponds to the late night time period. While the gate is shut off, the counter is incremented (line L23), and the counter value reaches Th2 at t24. As a result, the completion flag of the second item is turned ON (line L24). In response to the completion of the maintenance, the control device 250 stops transmitting the first cutoff request signal at t25 (line L22). In response, the control device 112 releases the gate cutoff at t26 (line L21).

FIG. 6 is a flowchart illustrating a third example of a method for switching the open/closed state of power storage device 210. A series of processes from S61 to S67 is executed by the control device 250, a series of processes from S71 to S77 is executed by the control device 112, and a series of processes from S81 to S83 are executed by the mobile terminal 500. The control device 250 monitors the success or failure of the cutoff request condition by repeatedly executing a series of processes from S61 to S67.

Referring to FIG. 6 together with FIG. 1, in S61, control device 250 determines whether a predetermined second shutoff request condition is satisfied. If the second cutoff request condition is satisfied (YES in S61), the control device 250 sends a second cutoff request signal requesting permission for SMR cutoff (opening of the power storage device 210) to the control device in S62. 112.

In this embodiment, the second cutoff request condition is that the degree of variation in cell voltage in the power storage device 210 (battery assembly) exceeds a predetermined level (first SMR cutoff requirement), and This includes not having received a notice of disapproval (second SMR blocking requirement). The second shutoff requirement is met when both the first and second SMR shutoff requirements are met, and is not met when either requirement is not met. For example, the control device 250 determines an index value (eg, standard deviation) indicating the degree of variation in cell voltage, and determines that the first SMR cutoff requirement is satisfied when the index value exceeds a predetermined value. In this embodiment, the second cutoff request signal including the degree of cell voltage variation (index value) acquired in S61 is transmitted in S62. The second SMR cutoff requirement is satisfied when a predetermined period of time has elapsed since a NO determination was made in S63, which will be described later. If NO is determined in S63, the second SMR cutoff requirement will not be satisfied until the predetermined time period has elapsed. The second cutoff requirement condition in S61 corresponds to an example of the "first condition" according to the present disclosure.

When the control device 112 receives the second cutoff request signal (S62), it starts a series of processes from S71 to S77. In S71, the control device 112 transmits a reply request signal requesting a reply of the user signal to the user (mobile terminal 500). The reply request signal includes a notification that an SMR shutdown request has occurred.

When the mobile terminal 500 receives the reply request signal, it starts a series of processes from S81 to S83. In S81, the mobile terminal 500 pops up a screen displaying a predetermined message and requests the user to input an input indicating whether or not to permit SMR blocking. The mobile terminal 500 determines whether there is an input from the user in S82. The user can select whether or not to permit SMR shutdown, taking into consideration the current situation (weather conditions, presence or absence of power outage, etc.). Then, when the user inputs information indicating either permission/non-permission into the mobile terminal 500 (YES in S82), the process advances to S83. In S83, the mobile terminal 500 transmits a user signal indicating the content of the user's input (permission/disapproval) to the control device 112. When the process of S83 is executed, the series of processes of S81 to S83 ends.

Upon receiving the user signal from the mobile terminal 500, the control device 112 transmits the user signal to the control device 250 in S72. Upon receiving the user signal from the control device 112, the control device 250 determines in S63 whether or not the SMR cutoff is permitted by the user. If the user signal indicates "not permitted" (NO in S63), the series of processes from S61 to S67 ends, and the process returns to the first step (S61). On the other hand, if the user signal indicates "permission" (YES in S63), the control device 250 opens the SMR 220 (a pair of relays) in the open state (blocking state) in S64, and then switches the SMR 220 into the blocking state. An SMR cutoff signal indicating that this has occurred is transmitted to the control device 112. Through the process of S64, the electric path connecting power storage device 210 and DC/DC converter 111 is cut off, and power storage device 210 enters an open circuit state (open state). Even if SMR 220 is in a cutoff state, control device 250 can receive power supply from at least one of power grid PG and power generation device 300.

In this embodiment, a YES determination in S63 means that the third condition is satisfied. Further, a NO determination in S63 means that the third condition is not satisfied. After transmitting the second cutoff request signal (S62) to the control device 112, the control device 250 controls the SMR 220 (at least one relay) so that the power storage device 210 enters an open circuit state when the third condition is satisfied. (S64).

After the processing in S72, the control device 112 determines in S73 whether or not the SMR cutoff signal has been received from the control device 250. When the control device 112 receives the SMR cutoff signal (YES in S73), control related to gate cutoff is executed in S74 to S77. In the process shown in FIG. 6, a determination of YES in S73 after the control device 112 receives the second cutoff request signal means that the second condition is satisfied. On the other hand, if the control device 112 does not receive the SMR cutoff signal from the control device 250 even after a predetermined period of time has elapsed since transmitting the user signal to the control device 250, the control device 112 determines NO in S73. In this case, the control device 112 determines that the SMR shutdown is not permitted by the user, and ends the series of processes from S71 to S77.

In S74 and S75, similarly to S14 and S15 in FIG. 2, respectively, the control device 112 executes gate cutoff, and a status signal of “gate cutoff” is transmitted from the control device 112 to the control device 250. In subsequent S76, the control device 112 determines whether a predetermined time has elapsed since the start of gate cutoff. The control device 112 repeats the processing of S74 to S76 until a predetermined time has elapsed (NO in S76), and when the predetermined time has elapsed (YES in S76), the gate cutoff is canceled in S77. The predetermined time may be a fixed value or may be variable. For example, the control device 112 lengthens the predetermined time as the degree of variation in cell voltage indicated by the second cutoff request signal increases. This makes it easier to maintain the gate-blocking state until the cell voltages are equalized.

After the process in S64, control device 250 executes a process related to maintenance of the opened power storage device 210 in S65, and then in S66 determines whether the gate is being shut off. The processes in S65 and S66 are similar to S21 and S23 in FIG. 2, respectively. However, in S65, only the second item (cell voltage equalization) may be executed. When the gate cutoff is released (NO in S66), the control device 250 returns the SMR 220 to the closed state (connected state) in S67. As a result, power storage device 210 enters a closed circuit state. By executing the process in S67, the series of processes in S61 to S67 is completed, and the process returns to the first step (S61).

Note that the maintenance items are not limited to the first item and second item described above. The maintenance items may include, for example, at least one of correction of various sensors for acquiring information on the power storage device 210, SOC learning by acquiring OCV of the power storage device 210, and estimation of the full charge capacity of the power storage device 210. good.

The control unit of the power supply system according to the embodiment described above is configured to execute all of the processes shown in FIGS. 2, 4, and 6. However, the present invention is not limited to this, and the control unit of the power supply system may execute only one or two of these processes. Further, the HMI (Human Machine Interface) is not limited to the mobile terminal 500, and a terminal other than the mobile terminal may be used as the HMI.

In the embodiment described above, the control device 250 corresponds to an example of a "first control device" according to the present disclosure. Further, the DC/DC converter 111 and the control device 112 of the power conversion unit 110 function as a "power conversion circuit" and a "second control device" according to the present disclosure, respectively. However, the present invention is not limited to this, and the circuit section 121 and the control section 122 of the PCS 120 may be configured to function as a "power conversion circuit" and a "second control device" according to the present disclosure, respectively. Further, power conversion circuit 230 shown in FIG. 1 may be provided outside power storage pack 200 (for example, power conversion unit 110). Control device 250 may receive power supply from power conversion unit 110. A power conversion circuit 230 provided in the power conversion unit 110 may be configured to step down the power from the power storage device 210 and output the step-down DC power to the control device 250 in the power storage pack 200. .

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments described above, and it is intended that all changes within the meaning and range equivalent to the claims are included.

100 building, 110 power conversion unit, 111 DC/DC converter, 111a switch, 112 control device, 120 PCS, 121 circuit section, 122 control section, 130 distribution board, 150 electric load, 200 electricity storage pack, 210 electricity storage device, 220 SMR, 230 power conversion circuit, 250 control device, 300 power generation device, 500 mobile terminal, PG power system.

Claims (5)

a stationary power storage device that supplies power to an electrical load;
a first control device that receives power from the power storage device;
a power conversion circuit located between the electrical load and the power storage device and not located between the power storage device and the first control device;
a second control device that controls the power conversion circuit;
Equipped with
The power conversion circuit includes at least one switch that switches between a connected state and a disconnected state of an electric line connecting the electric load and the power storage device,
When a predetermined first condition is satisfied, the first control device transmits a cutoff request signal requesting to open the power storage device to the second control device,
The second control device is a power supply system that controls the at least one switch so that the power storage device enters an open circuit state when a second condition including receiving the cutoff request signal is satisfied. The first condition includes that a predetermined period of time has passed since the last time maintenance was performed,
The power supply system according to claim 1, wherein the first control device executes processing related to maintenance of the power storage device while the power storage device is in an open circuit state when the second condition is satisfied. The power storage device includes a battery pack including a plurality of cells electrically connected to each other,
The first condition includes that the degree of variation in cell voltage in the assembled battery exceeds a predetermined level,
The power supply system according to claim 1, wherein the first control device equalizes the cell voltages in the assembled battery while the power storage device is in an open circuit state when the second condition is satisfied. The power supply system is
further comprising at least one relay located between the power storage device and the first control device, and located between the power storage device and the power conversion circuit,
The first control device is configured to receive power from at least one of an external power source and a power generation device,
After transmitting the cutoff request signal to the second control device, the first control device controls the power storage device to enter an open circuit state when a third condition including receiving permission from a user is satisfied. Power supply system according to any one of claims 1 to 3, controlling at least one relay. The second control device controls the at least one switch so that when a predetermined fourth condition is satisfied, the power storage device enters an open circuit state regardless of whether or not the cutoff request signal is received. The power supply system according to any one of claims 1 to 3, wherein a signal indicating that the power storage device has entered an open circuit state is transmitted to the first control device.

Images