Power system

Abstract

The ECU performs processing including the following steps: obtaining the current charge / discharge power P during V2H operation; incrementing a time counter T when the absolute value of the charge / discharge power P is less than a threshold value P1; notifying an inquiry message when the time counter T has reached T1, the current time is a time when no sunlight is expected and within a time period of late-night electricity, and the power storage device is fully charged; and stopping the V2H operation when stopping of the V2H operation is permitted.

Description

Technical Field

[0001] The present disclosure relates to an electric power system that supplies and receives electric power between a vehicle-mounted power storage device and a building or the like. Background Art

[0002] Known technologies supply and receive electricity between an on-board power storage device and buildings, power grids, and the like. For example, Japanese Patent Application Laid-Open No. 2017-046421 discloses the following technology. The on-board power storage device is charged using low-cost late-night electricity. During the day, the electricity charged to the power storage device is used within the building to save on electricity costs, or supplied to the power grid to mitigate peak demand for electricity. The power storage device is also charged so that its state of charge (SOC) reaches a specified level at a desired time (e.g., when no one is home). Summary of the Invention

[0003] To ensure high responsiveness in supplying and receiving power as described above, power supply and reception between the onboard power storage device and the building is maintained as long as no stop command is issued by a user, such as a management system that manages power to the power grid. This maintains the conductive state of electronic components, such as capacitors, placed between the onboard power storage device and the power grid. Consequently, these electronic components may degrade unnecessarily, leading to a shorter lifespan.

[0004] An object of the present disclosure is to provide an electric power system that reduces degradation of electronic components provided between an on-vehicle power storage device and a target for supplying and receiving electric power.

[0005] According to one aspect of the present disclosure, an electric power system includes: a vehicle equipped with a power storage device; a charge-discharge system that supplies and receives electric power between the vehicle and a facility outside the vehicle; a photovoltaic power generation device that supplies electric power generated using sunlight to the charge-discharge system; a notification device that notifies a user of predetermined information; and a controller that, when at least one of a first condition, a second condition, and a third condition is satisfied, uses the notification device to transmit an inquiry message, the inquiry message inquiring whether to allow the charge-discharge system to be stopped. The first condition includes the condition that the amount of electric power supplied and received between the power storage device and the facility is less than a threshold value. The second condition includes the condition that the current time is within a time period in which the amount of electric power generated by the photovoltaic power generation device is less than the threshold value. The third condition includes the following conditions: (i) the current time is within a time period for which a lower electricity rate is set than for any other time period of the day, and (ii) the amount of electric power stored in the power storage device is within a prescribed range corresponding to a fully charged state.

[0006] Accordingly, when the amount of power supplied and received between the power storage device and the utility is less than a threshold, when the current time is within a time period when the amount of power generated by the photovoltaic power generation device is less than a threshold, or when the current time is within a time period when electricity rates are lower than during any other time of day and the power storage device is fully charged, a query message inquiring whether to allow the charge-discharge system to be stopped can be displayed, prompting the user to stop the charge-discharge system. Since the charge-discharge system is stopped by notification of the query message, the conductive state between the power storage device and the utility is eliminated. Consequently, unnecessary degradation of electronic components can be reduced, and a reduction in their lifespan can be suppressed.

[0007] In one embodiment, when the first condition and the third condition are satisfied, the controller notifies the inquiry information using the notification device.

[0008] Accordingly, when the amount of power supplied and received between the power storage device and the utility is less than a threshold, the current time is within a time period where electricity rates are lower than those during any other time period, and the power storage device is fully charged, a notification message inquiring whether to allow the charge-discharge system to be stopped can be sent, prompting the user to stop the charge-discharge system. Since the charge-discharge system is stopped by notification of the inquiry message, the conductive state between the power storage device and the utility is eliminated. Consequently, unnecessary degradation of electronic components can be reduced, and a reduction in their lifespan can be suppressed.

[0009] In another embodiment, when the charge and discharge system is stopped and when a state satisfying at least any one of the second and third conditions changes to a state not satisfying at least any one of the second and third conditions, the controller activates the charge and discharge system.

[0010] Accordingly, when the state where at least one of the second and third conditions is satisfied changes to a state where at least one of the second and third conditions is no longer satisfied, there is a high probability that a request for power supply and reception will be made between the power storage device and the facility. Therefore, since the charging and discharging system is activated, power can be supplied and received between the power storage device and the facility with high responsiveness in response to the request.

[0011] According to another aspect of the present disclosure, an electric power control system includes: a vehicle equipped with a power storage device; a charge and discharge system that supplies and receives electric power between the vehicle and facilities outside the vehicle; a photovoltaic power generation device that supplies electric power generated using sunlight to the charge and discharge system; and a controller that controls the charge and discharge system. When all of the first, second, and third conditions are met, the controller stops the charge and discharge system. The first condition includes a condition that the amount of electric power supplied and received between the power storage device and the facility is less than a threshold value. The second condition includes a condition that the current time is a time within a time period in which the amount of electric power generated by the photovoltaic power generation device is less than a threshold value. The third condition includes the following conditions: (i) the current time is a time within a time period in which an electric power rate lower than that of any other time period of the day is set, and (ii) the amount of electric power stored in the power storage device is within a prescribed range corresponding to a fully charged state.

[0012] Accordingly, the charging and discharging system is stopped when the current time is within a time period when the amount of electricity generated by the photovoltaic power generation device is less than a threshold, when the current time is within a time period when electricity rates are lower than those at any other time of day, and when the power storage device is fully charged. This eliminates the conductive state between the power storage device and the facility, thereby reducing unnecessary degradation of electronic components and suppressing a reduction in their lifespan.

[0013] In one embodiment, when the charge and discharge system is stopped and when a state satisfying at least any one of the second and third conditions changes to a state not satisfying at least any one of the second and third conditions, the controller activates the charge and discharge system.

[0014] Accordingly, when the state where at least one of the second and third conditions is satisfied changes to a state where at least one of the second and third conditions is no longer satisfied, there is a high probability that a request for power supply and reception will be made between the power storage device and the facility. Therefore, since the charging and discharging system is activated, power can be supplied and received between the power storage device and the facility with high responsiveness in response to the request.

[0015] The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic configuration example of an electric power system is shown.

[0017] Figure 2 Show Figure 1 Example of the configuration of the house and vehicle shown in .

[0018] Figure 3 is a flowchart illustrating an example process executed by the ECU.

[0019] Figure 4 is a (first) flowchart showing an example process executed by the ECU in the modification.

[0020] Figure 5 is a (second) flowchart showing an example process executed by the ECU in the modification.

[0021] Figure 6 is a (third) flowchart showing an example process executed by the ECU in the modification.

[0022] Figure 7 is a (fourth) flowchart showing an example process executed by the ECU in the modification.

[0023] Figure 8 is a (fifth) flowchart showing an example process executed by the ECU in the modification. DETAILED DESCRIPTION

[0024] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are marked with the same reference numerals, and their description will not be repeated.

[0025] Figure 1 Schematic configuration example of the power system 1 is shown. Figure 1 As shown, the power system 1 includes a house 10 , a vehicle 20 , a connection cable 15 , a connection connector 17 , a power grid 30 , and a power transmission line 35 .

[0026] The house 10 is connected to a power transmission line 35 and can supply and receive power to and from a power grid (electricity network) 30 via the power transmission line 35. The house 10 can also supply and receive power to and from a vehicle 20 connected to the house 10 via a connection cable 15 and a connection connector 17.

[0027] Vehicle 20 is an electric vehicle equipped with a power storage device as a direct current (DC) power source, and is, for example, a battery-electric vehicle. Vehicle 20 is electrically connected to house 10 via a connection cable 15 and a connection connector 17. Vehicle 20 can generate and supply electricity equivalent to commercial power to house 10, and can also be supplied with electricity from house 10 to charge the power storage device. In other words, vehicle 20 can serve as a power source for house 10. Alternatively, house 10 can supply electricity to grid 30 using vehicle 20 as a power source.

[0028] The connection cable 15 is a power line for electrically connecting the vehicle 20 to the house 10. The connection connector 17 is a connector for electrically connecting the connection cable 15 to the vehicle 20.

[0029] Grid 30 is a commercial power system composed of numerous power generation facilities that generate transmission line power. Grid 30 is connected to various power generation facilities, such as thermal power plants, nuclear power plants, wind power generation facilities, hydroelectric power generation facilities, and photovoltaic power generation facilities. It is also connected to any other structures, such as houses or facilities. Furthermore, when a vehicle equipped with a power storage device is connected to such a structure, grid 30 can be supplied with power using the power storage device as a power source.

[0030] Figure 2 Show Figure 1 The configuration example of the house 10 and the vehicle 20 shown in FIG. Figure 2 As shown, the vehicle 20 includes a system main relay (SMR) 21 , a power control unit (PCU) 22 , a power storage device 29 , a motor generator (MG) 61 , a power transmission gear 65 , drive wheels 66 , and an electronic control unit (ECU) 100 .

[0031] The SMR 21 is a relay circuit electrically connected between the power storage device 29 and the PCU 22. The closing / opening of the SMR 21 is controlled by a command from the ECU 100.

[0032] PCU 22 exchanges power between power storage device 29 and MG 61 according to a command from ECU 100. PCU 22 includes, for example, an inverter (not shown) that receives power from power storage device 29 and drives MG 61, and a converter that adjusts the level of DC voltage supplied to the inverter.

[0033] The power storage device 29 is a rechargeable DC power source and includes, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery with a liquid or solid electrolyte. The power storage device 29 may be a capacitor such as an electric double-layer capacitor. The power storage device 29 supplies the PCU 22 with electric power used to generate the driving force for the vehicle 20. Furthermore, the power storage device 29 is charged by electric power generated by regenerative braking of the MG 61, discharged by driving operation of the MG 61, charged by electric power supplied from outside the vehicle, and discharged by electric power supplied to the outside of the vehicle.

[0034] MG 61 is a three-phase AC rotating electric machine and is, for example, a permanent magnet synchronous motor including a rotor having embedded permanent magnets. MG 61 functions as an electric motor (motor) and an electric generator (generator). MG 61 is connected to power storage device 29 via PCU 22 .

[0035] MG 61 is driven by an inverter included in PCU 22, for example, during travel of vehicle 20. The power of MG 61 is transmitted to drive wheels 66 via a power transmission gear 65, which is composed of a differential gear or the like. For example, during braking of vehicle 20, MG 61 is driven by drive wheels 66 and operates as a generator to perform regenerative braking. The electric power generated by MG 61 is stored in power storage device 29 via PCU 22.

[0036] Vehicle 20 also includes a charge / discharge relay 26, a power converter 27, and an inlet 28 as components for external charging or external power supply. Inlet 28 is coupled to connection connector 17 of house 10. Connection connector 17 is coupled to a home energy management system (HEMS) 11 of house 10 via a connection cable 15. Figure 2 The connection connector 17 is shown attached to and detachable from the inlet 28. The connection connector 17 is attached to the inlet 28 when external charging or external power supply is performed, and is detached from the inlet 28 when the vehicle 20 is running.

[0037] During external charging of power storage device 29, electric power is supplied from HEMS 11 to power converter 27 via connection cable 15, connection connector 17, and inlet 28. The supplied electric power is converted in power converter 27 into electric power capable of charging power storage device 29 (hereinafter referred to as charging power), and the converted charging power is supplied to power storage device 29.

[0038] Conversely, during external power supply of the power storage device 29 , power is converted into prescribed power (eg, AC power) in the power converter 27 , and the converted AC power is supplied to the HEMS 11 via the inlet 28 , the connection connector 17 , and the connection cable 15 .

[0039] Charge / discharge relay 26 is a relay circuit electrically connected between power storage device 29 and power converter 27. When charge / discharge relay 26 is closed and SMR 21 is closed, power can be transmitted between inlet 28 and power storage device 29.

[0040] The power converter 27 is electrically connected between the charge / discharge relay 26 and the inlet 28. Based on commands from the ECU 100, the power converter 27 converts the power supplied from the HEMS 11 into charging power, or converts the power from the power storage device 29 into supplyable power (e.g., AC power of 100V). The charge / discharge system in this embodiment includes the HEMS 11, the connection cable 15, the connection connector 17, the SMR 21, the charge / discharge relay 26, the power converter 27, and the inlet 28.

[0041] The ECU 100 includes a CPU 101, a memory 102, an input / output (I / O) port (not shown) for inputting and outputting various signals, and the like. The ECU 100 controls various devices in the vehicle 20 (such as the SMR 21, the PCU 22, the charge / discharge relay 26, and the power converter 27) so that the vehicle 20 enters a desired state. The various types of control performed by the ECU 100 are executed through software processing, that is, by the CPU 101 reading a program stored in the memory 102. The various types of control performed by the ECU 100 can be processed not only through software processing but also through dedicated hardware (electronic circuits).

[0042] A battery temperature sensor 110 , a battery current sensor 112 , and a battery voltage sensor 114 are connected to the ECU 100 .

[0043] The battery temperature sensor 110 detects a temperature TB at a predetermined location of the power storage device 29 (e.g., the location with the highest temperature in the power storage device 29) and transmits a signal indicating the detected temperature TB to the ECU 100. The battery current sensor 112 detects a current IB flowing through the power storage device 29 and transmits a signal indicating the detected current IB to the ECU 100. The battery voltage sensor 114 detects a voltage VB between the terminals of the power storage device 29 and transmits a signal indicating the detected voltage VB to the ECU 100.

[0044] The vehicle 20 also includes a wireless communication device 50 and a display device 53. The wireless communication device 50 is configured to communicate various types of information, etc. with the outside of the vehicle. The wireless communication device 50 includes a long-range communication module 51 and a short-range communication module 52. The long-range communication module 51 includes, for example, a Long Term Evolution (LTE) communication module. The long-range communication module 51 is configured to perform two-way data communication with a base station (not shown) in the communication network 6. The short-range communication module 52 is configured to perform two-way data communication with a mobile terminal 300 of a user of the vehicle 20 or with a house 10 within a short distance (e.g., about a few meters to about tens of meters) from the vehicle 20. The vehicle 20 can be configured to perform data communication with the house 10 via the long-range communication module 51 and the communication network 6 or to perform data communication directly with the house 10 via the short-range communication module 52.

[0045] The ECU 100 transmits various types of information (such as position information of the vehicle 20 ) to the house 10 or receives information from the house 10 via the wireless communication device 50 .

[0046] The display device 53 is provided at a location (e.g., an instrument panel) where the driver can visually recognize the display while the vehicle 20 is traveling. The display device 53 is composed of, for example, a liquid crystal display, an organic electroluminescence (EL) display, etc. The display device 53 displays text information, images, etc. in accordance with a control signal from the ECU 100.

[0047] The ECU 100 calculates the SOC of the power storage device 29 , for example, during travel of the vehicle 20 or when the vehicle 20 is parked and the connection connector 17 is connected to the inlet 28 to allow power to be supplied and received between the house 10 and the power storage device 29 .

[0048] The SOC calculation method may be, for example, various known techniques such as a technique using current value integration (coulomb counting) or a technique using estimation of open circuit voltage (OCV).

[0049] The house 10 includes a HEMS 11 , a communication device 12 , a photovoltaic power generation device 13 , a display device 14 , and an electrical device 18 .

[0050] The HEMS 11 is composed of, for example, a power supply board, a power converter, a controller, and the like. The HEMS 11 is electrically connected to the photovoltaic power generation device 13, the electrical device 18, the vehicle 20, and the power grid 30. The HEMS 11 includes an I / O unit 11a for supplying or receiving power to or from the vehicle 20, an I / O unit 11b for supplying or receiving power to or from the power grid 30, an output unit 11c for supplying power to the electrical device 18, and a relay 11f electrically connected between the photovoltaic power generation device 13, the power grid 30, and the I / O unit 11a.

[0051] The HEMS 11 also includes a CPU 11d and a memory 11e. The HEMS 11 controls the various devices in the HEMS 11 so that the desired state of power is supplied to and received from each connected target. The various types of control performed by the HEMS 11 are executed through software processing, that is, by the CPU 11d reading a program stored in the memory 11e. The various types of control performed by the HEMS 11 can be processed not only by software but also by dedicated hardware (electronic circuits).

[0052] HEMS 11 adjusts the amount of power supplied from grid 30 or photovoltaic power generation device 13 to electric device 18 or vehicle 20. Alternatively, HEMS 11 adjusts the amount of power supplied from vehicle 20 to electric device 18 or grid 30, for example.

[0053] The communication device 12 is configured to communicate with the wireless communication device 50 of the vehicle 20 through prescribed wireless communication or communication via the communication network 6 .

[0054] The photovoltaic power generation device 13 is a power generation device that generates electric power by converting sunlight energy into electric energy. The photovoltaic power generation device 13 supplies the generated electric power to the HEMS 11.

[0055] Display device 14 is provided at a position visible to a user in house 10. Display device 14 is composed of, for example, a liquid crystal display, an organic EL, etc. Display device 14 displays text information, images, etc. according to a control signal from HEMS 11. Electrical devices 18 include, for example, household appliances provided in house 10.

[0056] When the connection connector 17 is connected to the inlet 28 of the vehicle 20, the HEMS 11 supplies power from the power storage device 29 to the electrical device 18 in the house 10, or supplies power generated in the photovoltaic power generation device 13 or power from the power grid 30 to the vehicle 20. In the following description, this operation of supplying and receiving power between the house 10 and the vehicle 20 is referred to as a "V2H operation." For example, the HEMS 11 can perform the V2H operation when the connection connector 17 is connected to the inlet 28 of the vehicle 20, or when a request signal for performing the V2H operation is received from at least any one of the house 10, the vehicle 20, the management server 200, and the mobile terminal 300 when the connection connector 17 is connected to the inlet 28.

[0057] The management server 200 is configured to communicate with the house 10, the vehicle 20, and the mobile terminal 300 via the communication network 6. The management server 200 receives various types of information from each of the house 10, the vehicle 20, and the mobile terminal 300 via the communication network 6, or transmits various types of information to each of the house 10, the vehicle 20, and the mobile terminal 300 via the communication network 6.

[0058] The mobile terminal 300 is a terminal that can be carried by a user and includes, for example, a display device, an input device, and a communication device (not shown). The communication device of the mobile terminal 300 is configured to communicate with the house 10, the vehicle 20, and the management server 200 via the communication network 6.

[0059] The management server 200 receives a prescribed signal from the vehicle 20 and sends a display request signal to the mobile terminal 300 to perform a display corresponding to the received prescribed signal, or receives a signal indicating a result of an input device input to the mobile terminal 300 and sends a control request signal to the vehicle 20 to perform a control corresponding to the received signal indicating a result of the input.

[0060] In the electric power system 1 configured as described above, electric power is supplied and received between the power storage device 29 mounted on the vehicle 20 and the house 10 or the grid 30 .

[0061] To ensure high responsiveness in supplying and receiving power as described above, power is maintained between power storage device 29 mounted on vehicle 20 and house 10 as long as there is no stop command from the user, HEMS 11 managing power to grid 30, or management server 200. This maintains the conductive state of electronic components, such as capacitors, in the charging and discharging system between power storage device 29 and house 10. Consequently, the electronic components may degrade unnecessarily and have a shorter lifespan.

[0062] Therefore, in this embodiment, when the first, second, and third conditions described below are met, ECU 100 issues an inquiry message inquiring whether to allow the charging and discharging system to be stopped. The first condition includes the condition that the amount of power supplied and received between power storage device 29 and the facility is less than a threshold value. The second condition includes the condition that the current time is within a time period in which the amount of power generated by photovoltaic power generation device 13 is less than a threshold value. The third condition includes the condition that the current time is within a time period with a lower electricity rate than any other time period of the day, and the SOC indicating the amount of power stored in power storage device 29 is within a specified range corresponding to a fully charged state.

[0063] As a result, the user can be prompted to stop the charging and discharging system. If the charging and discharging system is stopped by notification of the inquiry information, the conductive state between power storage device 29 and house 10 is eliminated. This reduces unnecessary degradation of electronic components in the charging and discharging system between power storage device 29 and house 10, and prevents a reduction in the lifespan of the electronic components.

[0064] Below, we will refer to Figure 3 The processing executed by the ECU 100 is described. Figure 3 is a flowchart illustrating an example process performed by the ECU 100 .

[0065] In step (hereinafter referred to as S) 100, the ECU 100 determines whether the V2H operation is being performed.

[0066] When the flag indicating that the V2H operation is being performed is in the ON state, the ECU 100 determines that the V2H operation is being performed. For example, when the connection connector 17 is connected to the inlet 28 of the vehicle 20 and the ECU 100 receives a signal indicating a request for the V2H operation, the ECU 100 performs the V2H operation and sets the flag indicating that the V2H operation is being performed to the ON state.

[0067] When a predetermined operation is received on a predetermined operating device in house 10, a signal requesting execution of a V2H operation is transmitted from HEMS 11 to vehicle 20. Alternatively, when a prescribed operation is received on an input device of mobile terminal 300, a signal requesting execution of a V2H operation is transmitted from mobile terminal 300 to vehicle 20. Alternatively, during a power supply and demand adjustment period in which power is supplied and received between power storage device 29 of vehicle 20 and grid 30, a signal requesting execution of a V2H operation is transmitted from management server 200 to vehicle 20. When ECU 100 determines that a V2H operation is being executed ("YES" at S100), the process proceeds to S102.

[0068] At S102 , the ECU 100 obtains the current charge / discharge power P. For example, the ECU 100 obtains, as the current charge / discharge power P, the product of the current IB obtained using the battery current sensor 112 and the voltage VB obtained using the battery voltage sensor 114 .

[0069] At S104, the ECU 100 determines whether the absolute value (magnitude) of the charge / discharge power P is less than a threshold value P1. Threshold value P1 is a predetermined value used to determine whether power is not being supplied or received between the power storage device 29 and the HEMS 11. If the ECU 100 determines that the absolute value of the charge / discharge power P is less than threshold value P1 ("YES" at S104), the process proceeds to S106. If the ECU 100 determines that the absolute value of the charge / discharge power P is not less than threshold value P1 ("NO" at S104), the process proceeds to S108.

[0070] At S106 , the ECU 100 increments the time counter T. Specifically, the ECU 100 adds a predetermined value to the value stored in the memory 102 as the time counter T. The ECU 100 updates the value indicating the time counter T stored in the memory 102 using the added value.

[0071] At S108 , the ECU 100 resets the time counter T. Specifically, the ECU 100 sets the value stored in the memory 102 as the time counter T to an initial value (eg, zero). Then, the ECU 100 returns the process to S102 .

[0072] At S110, the ECU 100 determines whether the time counter T has reached T1. For example, when the value of the time counter T is a value not less than T1, the ECU 100 determines that the time counter T has reached T1. T1 is a value corresponding to a predetermined time, and the predetermined time is, for example, approximately several tens of minutes. When the ECU 100 determines that the time counter T has reached T1 ("YES" at S110), the process proceeds to S112. When the time counter T has not reached T1 ("NO" at S110), the process returns to S102.

[0073] At S112, the ECU 100 determines whether the current time is a time when no sunlight is expected. When the current time is a time within a predetermined time period, the ECU 100 determines that the current time is a time when no sunlight is expected. The predetermined time period is a time period in which the amount of electricity generated per prescribed time in the photovoltaic power generation device 13 is not greater than a threshold value. The predetermined time period includes, for example, a time period corresponding to the evening or night when there is no sunlight. The current time can be obtained using a clock device (not shown), or can be obtained from the HEMS 11, the management server 200, or the mobile terminal 300. When the ECU 100 determines that the current time is a time when no sunlight is expected ("Yes" at S112), the process proceeds to S114. When the ECU 100 determines that the current time is not a time when no sunlight is expected ("No" at S112), the process returns to S102.

[0074] At S114 , the ECU 100 determines whether the current time is within the time period of late-night electricity, and whether the power storage device 29 is substantially fully charged.

[0075] The midnight power time period is a time period in which a lower electricity rate is set than the daytime electricity rate, and is a predetermined time period. The midnight power time period may be stored in advance in the memory 102 or may be received from the management server 200 and stored in the memory 102.

[0076] For example, when the SOC of the power storage device 29 is greater than the threshold value SOC(0), the ECU 100 determines that the power storage device 29 is substantially fully charged. When the ECU 100 determines that the current time is within the time period of late-night power and the power storage device 29 is substantially fully charged ("YES" at S114), the process proceeds to S116. When the ECU 100 determines that the current time is not within the time period of late-night power, or when the ECU 100 determines that the power storage device 29 is not substantially fully charged ("NO" at S114), the process returns to S102.

[0077] At S116, the ECU 100 issues an inquiry message. For example, the ECU 100 issues an inquiry message inquiring whether to allow the V2H operation to be stopped. The ECU 100 sends a request signal to the HEMS 11 to cause the display device 14 to display the inquiry message. In response to the request signal from the ECU 100, the HEMS 11 causes the display device 14 to display the inquiry message inquiring whether to allow the V2H operation to be stopped. The information displayed on the display device 14 may include, for example, textual information or information including images.

[0078] When the inquiry information is displayed on the display device 14, the user can select whether to permit the stop of the V2H operation by operating an operating device (not shown) (such as a touch screen display) provided integrally with the display device 14 in the house 10 or an operating device (not shown) provided separately from the display device 14. When the operation of permitting the stop of the V2H operation is performed on the operating device in the house 10, the HEMS 11 transmits a signal to the vehicle 20 indicating that the user permits the stop of the V2H operation.

[0079] At S118, the ECU 100 determines whether stopping the V2H operation has been permitted. For example, if a user signal permitting stopping the V2H operation has been received from the HEMS 11 before a predetermined period has elapsed since the inquiry message was sent, the ECU 100 determines that stopping the V2H operation has been permitted. If the ECU 100 determines that stopping the V2H operation has been permitted ("Yes" at S118), the process proceeds to S120. If the ECU 100 determines that stopping the V2H operation has not been permitted ("No" at S118), the process returns to S102.

[0080] At S120, ECU 100 stops V2H operation. ECU 100 transmits a request signal to HEMS 11 requesting it to stop V2H operation and executes a process to stop power converter 27. During this process, ECU 100 stops power converter 27 and disconnects charge / discharge relay 26 and SMR 21. In response to the request signal from ECU 100, HEMS 11 disconnects its internal relay 11f. Consequently, house 10 and vehicle 20 are electrically disconnected from each other.

[0081] Based on the above-described structure and flowchart, a description will be given of the operation of the ECU 100 mounted on the vehicle 20 in the present embodiment.

[0082] For example, when vehicle 20 is parked in the parking lot of house 10, connection connector 17 is connected to inlet 28, and an operation requesting V2H operation is executed on mobile terminal 300, a request signal for V2H operation is transmitted from mobile terminal 300 to HEMS 11 of house 10 via communication network 6. Upon receiving the request signal from mobile terminal 300, HEMS 11 closes relay 11f and transmits a signal requesting V2H operation to ECU 100. Upon receiving the signal requesting V2H operation from HEMS 11, ECU 100 closes SMR 21 and charge / discharge relay 26. As a result, power from photovoltaic power generation device 13 or grid 30 can be supplied to power storage device 29, and power from power storage device 29 can be supplied to electrical device 18 or grid 30. Thus, the power supplied and received between house 10 and vehicle 20 is adjusted by HEMS 11. At this time, the flag indicating that V2H operation is being executed is in the ON state.

[0083] When V2H operation is being performed ("YES" at S100), the current charge / discharge power P is obtained from the product of battery current IB and battery voltage VB (S102). If, for example, the absolute value of the obtained charge / discharge power P is not less than threshold value P1 due to charging of power storage device 29 with power supplied from HEMS 11 ("NO" at S104), time counter T is reset to the initial value (S108), and the process of obtaining the current charge / discharge power P (S102) is repeated.

[0084] When, for example, the absolute value of the charge / discharge power P obtained by stopping charging after the power storage device 29 has been fully charged is less than the threshold value P1 ("YES" at S104), the time counter T is incremented (S106). Furthermore, when the state in which the absolute value of the charge / discharge power P is less than the threshold value P1 continues and the time counter T reaches T1 ("YES" at S110), the ECU 100 determines whether the current time is a time when no sunlight is expected (S112). When the current time is within the predetermined time period ("YES" at S112), the ECU 100 further determines whether the current time is within the time period of late-night power, and determines whether the power storage device 29 is substantially fully charged. In the case of being substantially fully charged, the SOC of the power storage device 29 is greater than the threshold value SOC(0) (S114).

[0085] If the current time is determined to be within the midnight power period and the power storage device 29 is substantially fully charged ("YES" at S114), the ECU 100 issues an inquiry message inquiring whether to permit stopping the V2H operation (S116). In other words, a request signal is output to the HEMS 11 requesting the display of the inquiry message. When the HEMS 11 receives the request signal, the text message and image are displayed on the display device 14. Subsequently, when the user performs an operation to permit stopping the V2H operation using the operating device in the house 10, a signal instructing the user to permit stopping the V2H operation is transmitted from the HEMS 11 to the ECU 100.

[0086] If stopping the V2H operation is permitted ("YES" at S118), the V2H operation is stopped (S120). Therefore, a stop process is executed in each of the ECU 100 and the HEMS 11, disconnecting the SMR 21 and the charge / discharge relay 26 of the vehicle 20, and disconnecting the relay 11f of the HEMS 11. As a result, the house 10 and the vehicle 20 are electrically disconnected from each other.

[0087] As described above, in the power system 1 according to this embodiment, when the absolute value of the charge / discharge power P is less than a threshold, the current time is during a period when the amount of power generated by the photovoltaic power generation device 13 per specified period is low, the current time is during a late-night electricity period when electricity rates are lower than those during daytime hours, and the power storage device 29 is substantially fully charged, an inquiry message is sent, inquiring whether to permit the stopping of the V2H operation performed by the charging and discharging system. Therefore, the notification of the inquiry message can prompt the user to stop the V2H operation. When the user permits the stopping of the V2H operation through the notification of the inquiry message, the V2H operation is stopped, eliminating the conductive state between the power storage device 29 and the house 10. Consequently, unnecessary degradation of electronic components can be reduced, and a reduction in the lifespan of electronic components can be suppressed. Consequently, a power system can be provided that reduces the degradation of electronic components in the circuit between the onboard power storage device and the power supply and reception destination.

[0088] Modifications will be described below.

[0089] Although the above embodiment has provided a description assuming that the threshold values Pl and Tl are predetermined, they may be values that can be changed by the user, for example. The notification frequency can thus be changed, resulting in a notification frequency that suits the user's preferences.

[0090] Although the above embodiment has provided a description assuming that the vehicle 20 is a battery electric vehicle, it is sufficient that the vehicle 20 is a vehicle having an on-board power storage device capable of supplying electric power to the house 10 or receiving electric power for charging from the house 10. The vehicle 20 may be, for example, a hybrid electric vehicle or a fuel cell electric vehicle having a power storage device mounted thereon.

[0091] Although the above embodiment has provided a description assuming that the house 10 and the vehicle 20 perform communication using wireless communication means, for example, wired communication such as Power Line Communication (PLC) via the connection cable 15 may be performed.

[0092] Although the above embodiment has provided a description assuming that the charge / discharge power P is obtained from the product of the battery current IB and the battery voltage VB, for example, a voltage sensor and a current sensor may be provided at the inlet 28, and the detection results of these sensors may be used to obtain the charge / discharge power P. Alternatively, signals indicating the detection results of the voltage sensor and the current sensor provided in the HEMS 11 may be received from the HEMS 11, and the ECU 100 may obtain the charge / discharge power P.

[0093] While the above embodiment has been described assuming that the inquiry information is displayed on the display device 14, the inquiry information may be displayed on the display device of the mobile terminal 300 instead of, or in addition to, the display device 14. The ECU 100 may transmit the display request signal directly to the mobile terminal 300 or indirectly to the mobile terminal 300 via the communication network 6 and the management server 200. The user may operate an input device of the mobile terminal 300 to select whether to allow the V2H operation to stop. Furthermore, the inquiry information may be displayed on the display device 53 instead of, or in addition to, the display device 14. The user may operate an operating device in the vehicle 20 to select whether to allow the V2H operation to stop.

[0094] While the above embodiment assumes that the time period used to determine whether the current time is a time when no sunlight is expected is predetermined, the ECU 100 may obtain a history of dates and the amount of power generated by the photovoltaic power generation device 13 at predetermined times, stored in the HEMS 11, and use this history to set the time period used to determine whether the current time is a time when no sunlight is expected. Alternatively, the ECU 100 may obtain weather forecast data from the management server 200 and set the time period used to determine whether the current time is a time when no sunlight is expected, in association with the current weather.

[0095] Although the above-mentioned embodiment has provided a description assuming that the inquiry information is visually notified by displaying text information, an image, or the like on a display device, the inquiry information may be auditorily notified by voice or the like.

[0096] While the above embodiment provides a description assuming that when a first condition is satisfied that the amount of power supplied and received between power storage device 29 and house 10 is small, a second condition is satisfied that the current time is within a time period when the amount of power generated by photovoltaic power generation device 13 is small, and a third condition is satisfied that the current time is within a time period when the electricity rate is lower than that of any other time period of the day and power storage device 29 is fully charged, an inquiry message inquiring whether to permit the stop of the V2H operation performed by the charge and discharge system is notified, the present disclosure is not particularly limited to such control. For example, ECU 100 may notify the inquiry message when any of the first, second, and third conditions are satisfied.

[0097] The following will refer to Figure 4 An example process executed by ECU 100 in the modification is described. Figure 4 is a (first) flowchart showing an example process executed by ECU 100 in the modification. Figure 4 Flowchart and Figure 3 The difference of the flowchart is that the processing of S200, the processing of S202 and the processing of S204 are included instead of the processing of S110, the processing of S112 and the processing of S114. Figure 3 Any other processing that is identical to that of the illustrated flowchart has been assigned the same step number, and therefore, detailed descriptions of such processing will not be repeated except for the points described below.

[0098] like Figure 4 As shown in the flowchart of FIG. 1 , when the time counter T is incremented (S106), the process proceeds to S200. At S200, the ECU 100 determines whether the time counter T has reached T1. When the ECU 100 determines that the time counter T has reached T1 ("YES" at S200), the process proceeds to S116. When the ECU 100 determines that the time counter T has not reached T1 ("NO" at S200), the process proceeds to S202.

[0099] At S202, the ECU 100 determines whether the current time is a time when no sunlight is expected. When the ECU 100 determines that the current time is a time when no sunlight is expected ("Yes" at S202), the process proceeds to S116. When the ECU 100 determines that the current time is not a time when no sunlight is expected ("No" at S202), the process proceeds to S204.

[0100] At S204, the ECU 100 determines whether the current time is within the time period for late-night power and whether the power storage device 29 is substantially fully charged. If the ECU 100 determines that the current time is within the time period for late-night power and the power storage device 29 is substantially fully charged ("YES" at S204), the process proceeds to S116. However, if the ECU 100 determines that the current time is not within the time period for late-night power or the power storage device 29 is not substantially fully charged ("NO" at S204), the process returns to S102.

[0101] Therefore, when at least any one of the first condition, the second condition, and the third condition is satisfied, the inquiry information is notified, and thus, the user can be prompted to stop the V2H operation.

[0102] Although the above embodiment has provided a description assuming that the inquiry information is notified when the first condition, the second condition, and the third condition are satisfied, for example, the ECU 100 may notify the inquiry information when the first condition and the third condition are satisfied.

[0103] Will refer to Figure 5 An example process executed by ECU 100 in another modification example is described. Figure 5 is a (second) flowchart showing an example process executed by ECU 100 in the modification. Figure 5 Flowchart and Figure 3 The difference between the flowchart of is that the processing of S112 is omitted. Figure 3 Any other processing that is identical to that of the illustrated flowchart has been assigned the same step number, and therefore, detailed descriptions of such processing will not be repeated except for the points described below.

[0104] like Figure 5 As shown in the flowchart of FIG. 1 , when the ECU 100 determines that the time counter T has reached T1 (YES at S110 ), the process proceeds to S114 .

[0105] Therefore, when the first and third conditions are satisfied, the inquiry information is notified, thereby prompting the user to stop the V2H operation.

[0106] Although the above embodiment has provided a description assuming that the inquiry information is notified when the first, second, and third conditions are satisfied, the V2H operation may be stopped when the first, second, and third conditions are satisfied.

[0107] Will refer to Figure 6 An example process executed by ECU 100 in another modification example is described. Figure 6 is a (third) flowchart showing an example process executed by ECU 100 in the modification. Figure 6 Flowchart and Figure 3 The difference between the flowchart of is that the processing of S116 and the processing of S118 are omitted. Figure 3 Any other processing that is identical to that of the illustrated flowchart has been assigned the same step number, and therefore, detailed descriptions of such processing will not be repeated except for the points described below.

[0108] like Figure 6 As shown in the flowchart of FIG1 , when the ECU 100 determines that the current time is within the time period of late-night electricity and the power storage device 29 is substantially fully charged (YES at S114 ), the process proceeds to S120 .

[0109] Therefore, when the first, second, and third conditions are satisfied, the V2H operation is stopped, thereby eliminating the conductive state between the power storage device 29 and the house 10. Therefore, unnecessary degradation of electronic components can be reduced, and reduction in the life of electronic components can be suppressed.

[0110] Although the above embodiment has provided a description assuming that inquiry information is notified when the first, second, and third conditions are satisfied, inquiry information may be notified when a fourth condition is satisfied in addition to the first, second, and third conditions.

[0111] The fourth condition includes the condition that the auxiliary battery's discharge prohibition count exceeds a threshold value N1. An auxiliary battery (not shown) is mounted on vehicle 20 to supply power to auxiliary equipment (including ECU 100) mounted on vehicle 20. ECU 100 detects the auxiliary battery's remaining charge or voltage using sensors or the like. When the detected remaining charge is not greater than a threshold value, or when the voltage is not greater than a threshold value, ECU 100 prohibits discharge of the auxiliary battery. While prohibiting discharge of the auxiliary battery, ECU 100 counts the discharge prohibition count. Therefore, as the auxiliary battery's discharge prohibition count increases, the longer the vehicle 20 remains unattended.

[0112] Will refer to Figure 7 An example process executed by ECU 100 in another modification example is described. Figure 7 is a (fourth) flowchart showing an example process executed by ECU 100 in the modification. Figure 7 Flowchart and Figure 3 The difference between the flowchart of is that the process of S300 is included between the process of S114 and the process of S116. Figure 3 Any other processing that is identical to that of the illustrated flowchart has been assigned the same step number, and therefore, detailed descriptions of such processing will not be repeated except for the points described below.

[0113] like Figure 7As shown in the flowchart of , when the current time is within the time period of late-night electricity and the power storage device 29 is substantially fully charged (YES at S114 ), the process proceeds to S300 .

[0114] At S300, the ECU 100 determines whether the auxiliary battery's discharge inhibit count is greater than a threshold value N1. Since the discharge inhibit count is as described above, its detailed description will not be repeated. If the ECU 100 determines that the auxiliary battery's discharge inhibit count is greater than the threshold value N1 ("YES" at S300), the process proceeds to S116. If the ECU 100 determines that the discharge inhibit count is not greater than the threshold value N1 ("NO" at S300), the process returns to S102.

[0115] Therefore, when the first, second, third, and fourth conditions are satisfied, the inquiry information is notified. When power is not supplied and received and when the vehicle 20 is not operated continuously, the user can be prompted to stop the V2H operation accordingly.

[0116] The above embodiment has been described assuming that when the first, second, and third conditions are satisfied, inquiry information is notified and the V2H operation is stopped due to notification of permission to stop. Alternatively, when the V2H operation is stopped due to satisfaction of the first, second, and third conditions, the V2H operation may be resumed when at least one of the first, second, and third conditions is not satisfied.

[0117] The following will refer to Figure 8 An example process executed by ECU 100 in another modification example is described. Figure 8 is a (fifth) flowchart showing an example process executed by ECU 100 in the modification. Figure 8 Flowchart and Figure 3 The flowchart of is different in that the processing of S400, the processing of S402, the processing of S404, and the processing of S406 are added, and the processing of S408 is performed instead of the processing of S120. Figure 3 Any other processing that is identical to that of the illustrated flowchart has been assigned the same step number, and therefore, detailed descriptions of such processing will not be repeated except for the points described below.

[0118] like Figure 8 As shown in the flowchart of , when the ECU 100 determines that the V2H operation is not being performed (“NO” at S100 ), the process proceeds to S400 .

[0119] At S400, the ECU 100 determines whether the stop flag is in the ON state. When the stop flag is in the ON state, it indicates that the first, second, and third conditions described below are satisfied, and that the V2H operation has stopped because the user has permitted the V2H operation to stop. If the ECU 100 determines that the stop flag is in the ON state ("YES" at S400), the process proceeds to S102. If the ECU 100 determines that the stop flag is not in the ON state ("NO" at S400), the process returns to S100.

[0120] When the ECU 100 determines that the current time is within the time period of late-night electricity and the power storage device 29 is substantially fully charged (YES at S114 ), the process proceeds to S402 .

[0121] At S402, the ECU 100 determines whether the stop flag is in the OFF state. When the ECU 100 determines that the stop flag is in the OFF state ("YES" at S402), the process proceeds to S116. When the ECU 100 determines that the stop flag is in the ON state ("NO" at S402), the process ends.

[0122] After the time counter T is reset (S108), when the ECU 100 determines that the time counter T has not reached T1 ("No" at S110), when the ECU 100 determines that the current time is not a time when no sunlight is expected ("No" at S112), or when the ECU 100 determines that the current time is not within the late night power time period or the power storage device 29 is not approximately fully charged ("No" at S114), the processing proceeds to S404.

[0123] At S404, the ECU 100 determines whether the stop flag is in the ON state. When the ECU 100 determines that the stop flag is in the ON state ("YES" at S404), the process proceeds to S306. When the ECU 100 determines that the stop flag is not in the ON state ("NO" at S404), the process returns to S102.

[0124] At S406, the ECU 100 restarts the V2H operation. The ECU 100 sends a signal indicating a request to execute the V2H operation to the HEMS 11, and closes the SMR 21 and the charge / discharge relay 26. The ECU 100 also sets the stop flag to the OFF state.

[0125] When the ECU 100 determines that the stop of the V2H operation has been permitted (YES at S118 ), the process proceeds to S408 .

[0126] At S408, the ECU 100 stops the V2H operation. Since the operation of stopping the V2H operation is similar to the operation of stopping the V2H operation at S120, its detailed description will not be repeated. At this time, the ECU 100 sets the stop flag to the ON state.

[0127] Therefore, when the first condition, the second condition, and the third condition are satisfied, and when the stop flag is in the OFF state ("Yes" at S402), the inquiry information is notified (S116), and when the stop of the V2H operation is permitted ("Yes" at S118), the V2H operation is stopped and the stop flag is set to the ON state.

[0128] Therefore, when the V2H operation is stopped ("No" at S100) and the stop flag is in the ON state ("Yes" at S400), the ECU 100 determines whether each of the first condition, the second condition, and the third condition is satisfied. When at least any one of the conditions is not satisfied ("No" at S110, "No" at S112, or "No" at S114), the stop flag is in the ON state ("Yes" at S404), and accordingly, the ECU 100 resumes the V2H operation.

[0129] Therefore, when it is likely that supply and reception of power will be requested between power storage device 29 and house 10, the charge and discharge system can be activated to resume V2H operation, thereby supplying and receiving power between power storage device 29 and house 10 with high responsiveness in response to the request.

[0130] Some or all of the above-described modifications may be appropriately performed in combination.

[0131] While the present disclosure has been described and illustrated in detail, it is to be clearly understood that the present disclosure is by way of illustration and example only and is not to be regarded as limiting, the scope of the present disclosure being construed by the terms of the appended claims.

Claims

1. Power system, including: a vehicle having an electric storage device mounted thereon; a charging and discharging system that supplies and receives electric power between the vehicle and facilities external to the vehicle; a photovoltaic power generation device that supplies electricity generated using sunlight to the charging and discharging system; a notification device that notifies a user of predetermined information; as well as The controller, when the first condition and the second condition are satisfied, notifies the inquiry information using the notification device, the inquiry information inquiring whether the stop of the charging and discharging system is permitted, wherein: The first condition includes a condition that the magnitude of electric power supplied and received between the power storage device and the facility is smaller than a threshold value, and The second condition includes the following conditions: (i) the current time is a time within a time period for which a lower electricity rate than an electricity rate for any other time period of the day is set, and (ii) the amount of electric power stored in the power storage device is within a prescribed range corresponding to a fully charged state.

2. Power system, including: a vehicle having an electric storage device mounted thereon; a charging and discharging system that supplies and receives electric power between the vehicle and facilities external to the vehicle; a photovoltaic power generation device that supplies electricity generated using sunlight to the charging and discharging system; as well as A controller that controls the charge and discharge system, wherein When all of the first condition, the second condition, and the third condition are satisfied, the controller stops the charge and discharge system. The first condition includes a condition that the magnitude of the electric power supplied and received between the power storage device and the facility is smaller than a threshold value, The second condition includes a condition that the current time is a time within a time period in which the amount of electric power generated by the photovoltaic power generation device is less than a threshold value, and The third condition includes the following conditions: (i) the current time is a time within a time period for which a lower electricity rate than an electricity rate for any other time period of the day is set, and (ii) the amount of electric power stored in the power storage device is within a prescribed range corresponding to a fully charged state.

3. The power system according to claim 2, wherein: The controller activates the charge and discharge system when the charge and discharge system is stopped and when a state in which all of the first condition, the second condition, and the third condition are satisfied changes to a state in which at least any one of the first condition, the second condition, and the third condition is not satisfied.

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