Patent Publication Number: US-2023150387-A1

Title: Power system, vehicle, and information processor

Description:
This nonprovisional application is based on Japanese Patent Application No. 2021-185511 filed on Nov. 15, 2021 with the Japan Patent Office, the entire content of which is hereby incorporated by reference. 
     BACKGROUND 
     Field 
     The present disclosure relates to a power system, a vehicle, and an information processor. 
     Description of the Background Art 
     Japanese Patent Laying-Open No. 2019-97334 discloses a user using a setting device to separately set a charging power set value and a discharging power set value for a vehicle which includes a power storage device capable of being charged with and discharge an electric power from power equipment provided external to the vehicle. 
     SUMMARY 
     According to Japanese Patent Laying-Open No. 2019-97334, the user can adjust electric power charged to and discharged from the power storage device. On the other hand, however, with a power system which controls charging and discharging of a power storage device in accordance with the user settings, there can be a desire to demands charge with and discharge an electric power appropriately from the power storage device, from variety of perspectives such as inhibition of deterioration of the power storage device, the electricity cost charged to the user when the power equipment charges the vehicle, and CO2 emitted during generation of electric power to be supplied from the power equipment to the vehicle. 
     The present disclosure is made to solve such a problem, and an object of the present disclosure is to provide a power system, a vehicle, and an information processor that can combine a charging and discharging control desired by a user and the desire of the power system. 
     A power system according to a certain aspect of the present disclosure includes: 
     a vehicle on which a power storage device is mounted; charge and discharge equipment capable of conveying an electric power between the vehicle and outside of the vehicle;
 
an input device that receives an input operation from a user of the vehicle; a
 
notification device that notifies the user of information; a setting unit that sets a usable range of a state of charge (SOC) of the power storage device, in accordance with a user operation performed on the input device; and a charging and discharging control unit that controls charging and discharging of an electric power for the power storage device, based on the usable range set by the setting unit. The setting unit calculates an expected range of the usable range, and outputs the expected range to the notification device. Using the expected range, the notification device performs a process of guiding the user so that the usable range is within the expected range.
 
     According to the above configuration, in the situation where the user of the vehicle sets the SOC usable range, the notification device performs the process of guiding the user so that the usable range is within the expected range desired by the power system. According to this, the user can be encouraged to set the usable range so that the usable range is within the expected range, thereby combining the charging and discharging control desired by the user and the desire of the power system. 
     Preferably, in the power system, the input device receives a user operation for setting at least one of an upper limit SOC indicating an upper limit of use of the SOC and a lower limit SOC indicating a lower limit of use of the SOC. The setting unit calculates and outputs to the notification device at least one of an upper limit expected value indicating an expected value of the upper limit SOC and a lower limit expected value indicating an expected value of the lower limit SOC. The notification device notifies the user of the at least one of the upper limit expected value and the lower limit expected value. 
     According to this, the SOC usable range is set in accordance with the user&#39;s intent, while the SOC expected range being presented to the user, thereby combining the charging and discharging control desired by the user and the desire of the power system. 
     Preferably, in the power system, the input device receives a user input for setting at least one of an upper limit SOC indicating an upper limit of use of the SOC and a lower limit SOC indicating a lower limit of use of the SOC. The setting unit calculates and outputs to the notification device at least one of an upper limit expected value indicating an expected value of the upper limit SOC and a lower limit expected value indicating an expected value of the lower limit SOC. When the usable range set based on the user input is out of the expected range, the notification device gives a notification to the user, encouraging the user to change the usable range. 
     According to this, the SOC usable range is set in accordance with the user&#39;s intent, while the user being notified of the changes in the setting based on the SOC expected range, thereby combining the charging and discharging control desired by the user and the desire of the power system. 
     Preferably, in the power system, the setting unit predicts a scope of use of the SOC based on a usage schedule of the vehicle or a usage history of the vehicle, and calculates the expected range in accordance with the scope of use of the SOC. 
     According to this, after the completion of the most-recent external charging until the performance of the next external charging, the vehicle can travel using the electric power stored in the power storage device to an extent that causes no over-discharge from the power storage device. Accordingly, the deterioration of the power storage device due to being overcharged can be inhibited from developing, while preventing a situation where the vehicle is disabled. 
     Preferably, in the power system, the setting unit calculates the expected range, in accordance with an electricity cost during a time period in which the power storage device is charged by the charge and discharge equipment. 
     According to this, when the external charging is performed during a time period in which the electricity rate is expensive, the power usage for the external charging can be reduced by lowering the upper limit expected value of the expected range, resulting in reduction of the electricity cost charged to the user. When the external charging is performed during a time period in which the electricity rate is inexpensive, more power can be stored in the power storage device by raising the upper limit expected value, without increasing the electricity cost charged to the user. 
     Preferably, the power system further includes power generating equipment capable of supplying the charge and discharge equipment with an electric power generated using renewable energy. The setting unit calculates the expected range, in accordance with an amount of power generated by the power generating equipment during a time period in which the power storage device is charged by the charge and discharge equipment. 
     According to this, when the external charging is performed during a time period in which power generation by renewable energy increases, if a surplus power is generated at the house, the external charging can use the surplus power, without dumping it, by raising the upper limit expected value of the expected range. When the demand for electric power from the house increases, the electric power stored in the vehicle can be transmitted back to the house through the charge and discharge equipment. Accordingly, CO2 emitted during generation of electric power to be supplied by a power grid, can be reduced. 
     Preferably, in the power system, the charge and discharge equipment conveys an electric power between the vehicle and a power grid. When the vehicle approves a request to participate in adjustment of supply and demand of the power grid, the setting unit calculates the expected range so that the expected range is greater than when participating in the adjustment is not approved by the vehicle. 
     According to this, if the vehicle has a schedule to participate in a request to increase the electric power demand, the upper limit expected value of the expected range is set to a higher value, thereby increasing the amount of electric power charged by the external charging, contributing to an increase of the electric power demand. If the vehicle has a schedule to participate in a request to mitigate the power shortfall, the lower limit expected value of the expected range is set to a lower value, thereby increasing an amount of electric power supplied by the external power supply, contributing to mitigation of the power shortfall by increasing the backfeeding. The contribution of the vehicle to the adjustment of the supply and demand of the power grid can be enhanced by setting the SOC usable range, taking into account as such a request to participate in adjustment of the supply and demand of the power grid. As a result, the user of the vehicle can receive a large incentive from the administrator of the power grid. 
     Preferably, in the power system, the input device and the notification device include a terminal device of the user. The power system further includes a communication device. The communication device communicates with the setting unit and the terminal device. The communication device transmits to the terminal device the expected range calculated by the setting unit. 
     According to this, when the terminal device of the user is used to set the SOC usable range, the user can be encouraged to set the usable range so that the usable range is within the expected range. 
     Preferably, in the power system, the communication device transmits to the setting unit the usable range received by the terminal device. The charging and discharging control unit controls charging and discharging of an electric power for the power storage device, based on the usable range received by the setting unit. 
     According to this, an electric power is charged to and discharged from the power storage device in accordance with the SOC usable range set by the user. Thus, the charging and discharging control desired by the user is achieved. 
     A vehicle according to another aspect of the present disclosure has a power storage device mounted thereon. The vehicle is capable of conveying an electric power between the vehicle and outside of the vehicle through charge and discharge equipment. The vehicle includes: an input device that receives an input operation from a user of the vehicle; a notification device that notifies the user of information; and a controller that sets a usable range of a state of charge (SOC) of the power storage device, in accordance with a user operation performed on the input device, and controls charging and discharging of an electric power for the power storage device, based on the usable range. The controller calculates an expected range of the usable range, and outputs the expected range to the notification device. Using the expected range, the notification device performs a process of guiding the user so that the usable range is within the expected range. 
     According to the above configuration, in a situation where the user of the vehicle sets the SOC usable range, the notification device mounted on the vehicle performs the process of guiding the user so that the usable range is within the expected range desired by the power system. According to this, the charging and discharging control desired by the user and the desire of the power system can be combined. 
     An information processor according to another aspect of the present disclosure manages the power system. The power system comprises: a vehicle on which a power storage device is mounted; charge and discharge equipment capable of conveying an electric power between the vehicle and outside of the vehicle; an input device that receives an input operation from a user of the vehicle; and a notification device that notifies the user of information. The information processor includes: a communication device that communicates with the input device and the notification device; and a setting unit that sets a usable range of a state of charge (SOC) of the power storage device, in accordance with a user operation performed on the input device. The setting unit calculates an expected range of the usable range. The communication device transmits to the notification device the expected range calculated by the setting unit. 
     According to the above configuration, the information processor (e.g., the server), which manages the power system, performs the process of guiding the user via the notification device so that the SOC usable range is within the expected range desired by the power system. According to this, the user can be encouraged to set the usable range so that the usable range is within the expected range, thereby combining the charging and discharging control desired by the user and the desire of the power system. 
     The information processor according to another aspect of the present disclosure communicates with the vehicle. The vehicle has a power storage device mounted whereon, and capable of conveying an electric power between the vehicle and outside of the vehicle through charge and discharge equipment. The information processor includes: an input device that receives an input operation from a user of the vehicle; a notification device that notifies the user of information; and a setting unit that sets a usable range of a state of charge (SOC) of the power storage device, in accordance with a user operation performed on the input device. The setting unit calculates an expected range of the usable range, and outputs the expected range to the notification device. Using the expected range, the notification device performs a process of guiding the user to set the usable range so that the usable range is within the expected range. 
     According to the above configuration, the information processor (e.g., the user terminal), which communicates with the vehicle, performs the process of guiding the user so that the SOC usable range is within the expected range desired by the power system. According to this, the charging and discharging control desired by the user and the desire of the power system can be combined. 
     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 
         FIG.  1    is a diagram showing a configuration example of a vehicle to which a power system according to an embodiment according to the present disclosure is applied. 
         FIG.  2    is a diagram showing a schematic configuration of the power system according to the embodiment. 
         FIG.  3    is a diagram showing a specific configuration of an electronic control unit (ECU) included in the vehicle and a server. 
         FIG.  4    is a diagram showing a first example of a configuration screen for a state of charge (SOC) usable range. 
         FIG.  5    is a diagram showing a second example of the configuration screen of the SOC usable range. 
         FIG.  6    is a diagram showing a third example of the configuration screen of the SOC usable range. 
         FIG.  7    is a flowchart of a first example of the procedure of an SOC-usable-range setting process that is performed at the power system. 
         FIG.  8    is a flowchart of a second example of the procedure of the SOC-usable-range setting process that is performed at the power system. 
         FIG.  9    is a diagram schematically showing one example relationship between an electricity rate and an upper limit expected value. 
         FIG.  10    is a diagram schematically showing one example relationship between an amount of power generated by solar power generating equipment and the upper limit expected value. 
         FIG.  11    is a diagram showing a specific configuration of an ECU included in a vehicle and a server, according to another embodiment of the present disclosure. 
         FIG.  12    is a diagram showing a specific configuration of a user terminal according to another embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments according to the present disclosure will be described in detail, with reference to the accompanying drawings. Note that the same reference sign is used to refer to the same or like parts, and the description thereof will not be repeated. 
     &lt;Configuration of Vehicle&gt; 
       FIG.  1    is a diagram showing a configuration example of a vehicle applied to a power system according to an embodiment of the present disclosure. 
     As shown in  FIG.  1   , a vehicle  50  includes a battery  130  storing electric power for traveling. The battery  130  includes a secondary battery, for example, a lithium-ion battery or a nickel-hydrogen battery. Note that other power storage device, such as an electric double layer capacitor, may be employed, instead of the secondary battery. The battery  130  corresponds to one example of a “power storage device” according to the present disclosure. 
     The vehicle  50  includes an electronic control unit (hereinafter, referred to as an “ECU”)  150 . The ECU  150  performs a charging control and a discharging control over the battery  130 . The ECU  150  also controls communications with devices external to the vehicle  50 . 
     The vehicle  50  may be a battery electric vehicle (BEV) capable of traveling using only the electric power stored in the battery  130 , or a plug-in hybrid electric vehicle (PHEV) capable of travelling using both the electric power stored in the battery  130  and output power of an engine (not shown). The vehicle  50  may also be a vehicle that is operated by a user or capable of autonomous driving. The ECU  130  corresponds to one example of a “controller” according to the present disclosure. 
     The vehicle  50  further includes a monitoring module  131  that monitors conditions of the battery  130 . The monitoring module  131  includes various sensors for detecting conditions (e.g., voltage, current, and temperature) of the battery  130 , and outputs results of the detections to the ECU  150 . The monitoring module  131  may be a battery management system (BMS) that has, in addition to the sensor functions above, a state of charge (SOC) estimation function, a state of health (SOH) estimation function, a cell voltage equalization function, a diagnosis function, and a communications function. Based on the outputs of the monitoring module  131 , the ECU  150  can obtain the conditions (e.g., voltage, current, temperature, SOC, and internal resistance) of the battery  130 . 
     The EVSE  40  is electric vehicle supply equipment. The vehicle  50  includes an inlet  110  and a charger-discharger  120 , which support the power supply scheme of the EVSE  40 . The inlet  110  receives an electric power supplied external to the vehicle  50 . The inlet  110  also outputs an electric power supplied from the charger-discharger  120  to outside the vehicle  50 . The battery  130  is capable of receiving an electric power supplied from the inlet  110  and outputting an electric power to the inlet  110 . Note that the vehicle  50  may include an inlet for each power supply scheme so as to support multiple kinds of power supply schemes (e.g., an alternating-current power supply scheme and a direct-current power supply scheme). 
     The EVSE  40  includes a power supply circuit  41 . The EVSE  40  is connected to a charging cable  42 . The charging cable  42  may be connected to the EVSE  40  at all times or detachable from the EVSE  40 . The charging cable  42  has a connector  43  at a tip thereof, and includes a power line therein. 
     The inlet  110  is connectable to the connector  43  of the charging cable  42 . The inlet  110  includes a connector locking device  111 . The connector locking device  111  switches the connector  43  between a locked state and an unlocked state. As the connector  43  of the charging cable  42  coupled to the EVSE  40  is connected to the inlet  110  of the vehicle  50 , the EVSE  40  and the vehicle  50  are electrically connected together. This allows an electric power to be supplied from the EVSE  40  to the vehicle  50  through the charging cable  42 . 
     The charger-discharger  120  is disposed between the inlet  110  and the battery  130 . The charger-discharger  120  includes a relay which switches a power path from the inlet  110  to the battery  130  between on and off, and a power converter circuit (e.g., a bidirectional converter), none of which are shown. The relay and the power converter circuit are each controlled by the ECU  150 . 
     The vehicle  50  further includes a monitoring module  121  that monitors conditions of the charger-discharger  120 . The monitoring module  121  includes various sensors that detects conditions (e.g., voltage, current, and temperature) of the charger-discharger  120 , and outputs results of the detections to the ECU  150 . In the example of  FIG.  1   , the monitoring module  121  detects voltage and current input to the power converter circuit, and voltage and current output from the power converter circuit. 
     Connecting the EVSE  40  and the inlet  110  together via the charging cable  42  enables an electric power to be conveyed between the EVSE  40  and the vehicle  50 . This enables external charging by the vehicle  50  (i.e., charging of the battery  130  of the vehicle  50  with supply of an electric power from outside the vehicle  50 ). The electric power for the external charging is supplied from, for example, the EVSE  40  to the inlet  110  through the charging cable  42 . The charger-discharger  120  converts the electric power received by the inlet  110  into one that is appropriate for charging the battery  130  with, and outputs to the battery  130  the electric power obtained by the conversion. 
     Connecting the EVSE  40  and the inlet  110  together via the charging cable  42  also enables external power supply by the vehicle  50  (i.e., supply of an electric power from the vehicle  50  to the EVSE  40  through the charging cable  42 ). The electric power for the external power supply is supplied from the battery  130  to the charger-discharger  120 . The charger-discharger  120  converts the electric power supplied from the battery  130  into one that is appropriate for external power supply, and outputs to the inlet  110  the electric power obtained by the conversion. 
     When either the external charging or the external power supply is performed, the relay of the charger-discharger  120  is in a closed state (a connected state). When none of the external charging or the external power supply is performed, the relay of the charger-discharger  120  is in an open state (a disconnected state). Note that the configuration of the charger-discharger  120  is not limited to the above, and may be modified, as appropriate. 
     The ECU  150  includes a processor  151 , a random access memory (RAM)  152 , a storage device  153 , and a timer  154 . For example, a central processing unit (CPU) is employed as the processor  151 . The RAM  152  functions as a working memory temporality storing data processed by the processor  151 . 
     The storage device  153  is capable of saving the stored information. The storage device  153  includes, for example, a read only memory (ROM) and a rewritable nonvolatile memory. Besides programs, the storage device  153  stores information (e.g., maps, mathematical formulas, and various parameters) which are used in the programs. In the present embodiment, the processor  151  executes the programs stored in the storage device  153 , thereby the ECU  150  performing various controls. However, the various controls performed by the ECU  150  are not limited to be performed by software, and can be performed by dedicated hardware (electronic circuit). Note that the ECU  150  may include any number of processors, and a processor may be prepared for each predetermined control. 
     The timer  154  notifies the processor  151  of the arrival of a set time. Upon arrival of the time set to the timer  154 , the timer  154  transmits a signal for notifying the processor  151  of this. In the present embodiment, a timer circuit is employed as the timer  154 . However, the timer  154  may be implemented by software, rather than by hardware (the timer circuit). The ECU  150  can also obtain the current time by using a real-time clock (RTC) circuit (not shown) built in the ECU  150 . 
     The vehicle  50  further includes a travel drive unit  140 , an input device  160 , a notification device  170 , a communications equipment  180 , and driving wheels W. Note that the drive system of the vehicle  50  is not limited to the front-wheel drive illustrated in  FIG.  1   , and may be a rear-wheel drive or a four-wheel drive. 
     The travel drive unit  140  includes a power control unit (PCU) and a motor generator (MG), none of which are shown. The travel drive unit  140  causes the vehicle  50  to travel using the electric power stored in the battery  130 . For example, the PCU includes: a controller, which includes a processor; an inverter; a converter; and a relay (hereinafter, referred to as a “system main relay (SMR)”). The controller of the PCU receives instructions (control signals) from the ECU  150 , and controls the inverter, the converter, and the SMR of the PCU, in accordance with the instructions. The MG is, for example, a three-phase alternating-current (AC) motor generator, and driven by the PCU and thereby rotates the driving wheels W. The MG also regenerates an electric power, and supplies the electric power to the battery  130 . The SMR switches a power path from the battery  130  to the PCU between on and off. The SMR is in a closed state (the connected state) while the vehicle  50  is traveling. 
     The input device  160  receives user operations. The input device  160  is operated by the user, and outputs signals corresponding to user operations to the ECU  150 . The input device  60  may have a wired or wireless scheme. The input device  160  is, for example, various switches, various pointing devices, a keyboard, and a touch panel. The input device  160  may be an operating unit included in a car navigation system. The input device  160  may be a smart speaker which receives speech input. The input device  160  corresponds to one example of an “input device” according to the present disclosure. 
     The notification device  170  performs a predetermined inform process to the user (e.g., a passenger of the vehicle  50 ), in response to a request from the ECU  150 . The notification device  170  may include at least one of a display device (e.g., a touch panel display), a loudspeaker, and a lamp. The notification device  170  may be a meter panel, a head up display, or a car navigation system. The notification device  170  corresponds to one example of a “notification device” according to the present disclosure. Note that the input device  160  and the notification device  170  form an “interface” for interacting with the user. The input device  160  and the notification device  170  may be separate components or a one component. 
     The communications equipment  180  includes various communication interfaces (I/F). The communications equipment  180  may include a data communication module (DCM). The communications equipment  180  may include a 5G (the fifth-generation mobile communications system)-enabled communication I/F. The ECU  150  wirelessly communicates with communication devices external to the vehicle  50 , through the communications equipment  180 . 
     &lt;Configuration of Power System&gt; 
       FIG.  2    is a diagram showing a schematic configuration of the power system according to the present embodiment. 
     As shown in  FIG.  2   , a power system  1  according to the present embodiment includes a power grid PG, a home energy management system (HEMS)  15 , a switchboard  11 , solar power generating equipment  13 , a storage battery  14 , a server  30 , the EVSE  40 , the vehicle  50 , and a user terminal  80 . The vehicle  50  has the configuration as illustrated in  FIG.  1   . The HEMS  15 , the solar power generating equipment  13 , and the storage battery  14  are provided in a house  10  (e.g., a user&#39;s house) where the EVSE  40  is installed. 
     The user terminal  80  corresponds to one example of a “terminal device” carried by the user of the vehicle  50 . In the example of  FIG.  2   , smartphone which includes a touch panel display is employed as the user terminal  80 . However, the present disclosure is not limited thereto. Any terminal device can be employed as the user terminal  80 . 
     The vehicle  50  is electrically connected to the EVSE  40  via the charging cable  42 , while being parked in a parking area of the house  10  where the EVSE  40  is installed. The EVSE  40  is AC power supply equipment that supports backfeeding. The power supply circuit  41  converts an electric power supplied from the power grid PG into one that is appropriate for external charging, and also converts an electric power supplied from the vehicle  50  into one that is appropriate for backfeeding. However, the power system  1  may include power supply equipment that does not support backfeeding or include DC power supply equipment (e.g., a fast charger). 
     As the connector  43  of the charging cable  42  coupled to the EVSE  40  is connected to the inlet  110  of the vehicle  50 , communications are enabled between the vehicle  50  and the EVSE  40 , and an electric power can also be conveyed between the vehicle  50  and the EVSE  40 . The vehicle  50  electrically connected to the EVSE  40  is electrically connected to the power grid PG via the EVSE  40 . This completes preparation for external charging and external power supply. 
     The communications equipment  180  mounted on the vehicle  50  communicates with the EVSE  40  via the charging cable  42 . The communication scheme between the EVSE  40  and the vehicle  50  may be any, for example, a controller area network (CAN) or a power line communication (PLC). The communications equipment  180  also wirelessly communicates with the server  30  via a mobile communication network (telematics), for example. The signals exchanged between the communications equipment  180  and the server  30  may be encrypted. 
     Furthermore, in the present embodiment, the communications equipment  180  mounted on the vehicle  50  and the user terminal  80  wirelessly communicate with each other. The ECU  150  can control the user terminal  80  through wireless communications to cause the user terminal  80  to give notifications to the user. The communications between the communications equipment  180  and the user terminal  80  may be a short-range communication (e.g., a direct communication in the vehicle and in an area around the vehicle) such as Bluetooth (registered trademark). 
     A predetermined application software (hereinafter, simply referred to as an “app”) is installed in the user terminal  80 . The user terminal  80  can be carried by the user of the vehicle  50 , and exchange information with the HEMS  15  and the server  30  through the app. The user can operate the app through, for example, the touch panel display of the user terminal  80 . The touch panel display of the user terminal  80  can also give notifications to the user of the vehicle  50 . The user terminal  80  (the touch panel display) corresponds to one example of an “interface” according to the present disclosure for interaction with the user. The server  30  contacts the user of the vehicle  50  through a predetermined contact (e.g., the user terminal  80  or the communications equipment  180 ). 
     The HEMS  15  manages the supply and demand of an electric power that is used in the house  10 . The HEMS  15  wirelessly communicates with the user terminal  80  and the server  30  via the communication network. The HEMS  15  is electrically connected to the EVSE  40  and a consumer electronics (not shown) that runs on power supplied from the power grid PG. The HEMS  15  is also electrically connected to the solar power generating equipment (the solar panel)  13  and the storage battery  14 . 
     The solar power generating equipment  13  generates an electric power using the renewable energy, and the power output from the solar power generating equipment  13  varies depending on a meteorological condition. The storage battery  14  is a rechargeable power storage element, and, a secondary battery, typically, a lithium-ion battery, a nickel-hydrogen battery, or a lead storage battery, etc. is applied. Besides the electric power from the vehicle  50 , the storage battery  14  can be supplied with the electric power generated by the solar power generating equipment  13  and the electric power from the power grid PG. 
     Note that if a surplus power is generated at the house  10  (e.g., a surplus amount of electric power generated by the solar power generating equipment  13 ), the surplus power can be stored in the vehicle  50  through the EVSE  40 . Thereafter, in the event of an increase of the electric power demand from the house  10 , the electric power stored in the vehicle  50  can be transmitted back to the house  10  through the EVSE  40 . 
     The HEMS  15  measures the amount of electric power supplied from the EVSE  40  to the vehicle  50 . The HEMS  15  also measures the amount of electric power that is back fed from the vehicle  50  to the EVSE  40 . The HEMS  15  stores a measured power usage and transmits it to the server  30 . The HEMS  15  also measures the amount of electric power generated by the solar power generating equipment  13 . The HEMS  15  stores the measured amount of generated power, and transmits it to the server  30 . The HEMS  15  may periodically transmit the measured power usage and the measured amount of generated power to the server  30 , or transmit them to the server  30  upon request. 
     The server  30  is capable of communications with the vehicle  50 , the HEMS  15 , and the user terminal  80 . The server  30  belongs to the administrator of the power grid PG, and corresponds to a management computer for the power grid PG. The server  30  corresponds to one example of an “information processor” according to the present disclosure. 
     The server  30  includes a controller  31 , a storage device  32 , and a communication device  33 . The controller  31  includes a processor, performs predetermined information processing and controls the communication device  33 . The storage device  32  is capable of saving various information. Besides the programs executed by the controller  31 , the storage device  32  stores information (e.g., maps, mathematical formulas, and various parameters) which are used in the programs. The communication device  33  includes various communication I/Fs. The controller  31  communicates externally through the communication device  33 . 
     &lt;SOC Usable Range of Battery  130 &gt; 
     As noted above, in the power system  1 , the external charging and the external power supply by the vehicle  50  are enabled by the connector  43  of the charging cable  42  coupled to the EVSE  40  being connected to the inlet  110  of the vehicle  50 . Accordingly, the travel distance of the vehicle  50  can be ensured by fully charging the battery  130  by the external charging. In addition, a power demand peak can be mitigated by supplying the house  10  (or the power grid PG) with the electric power that is stored in the battery  130  by the external power supply during a time period that has a peak electric power demand from the house  10  (or the power grid PG). 
     In the present embodiment, the user can set an SOC usable range of the battery  130 . The “SOC usable range,” as used herein, is defined by an “upper limit SOC” indicating the upper limit of use of the SOC and a “lower limit SOC” indicating the lower limit of use of the SOC. The user can set at least one of the upper limit SOC and the lower limit SOC, using an input device that receives user operations. Note that the user terminal  80  or the input device  160  mounted on the vehicle  50  can be used as the input device. 
     Meanwhile, the deterioration of the battery  130 , represented by a secondary battery, is promoted by the battery  130  being kept in the over-charged state or the over-discharged state. Therefore, if the user sets the upper limit SOC to a high SOC regime, the battery  130  is kept in the over-charged state after the completion of the external charging until the next travel, which may promote the deterioration of the battery  130 . If the user sets the lower limit SOC to a low SOC regime, the battery  130  is kept in the over-discharged state after the vehicle  50  travels or after the end of the external power supply, which may promote the deterioration of the battery  130 . Accordingly, it is required that the SOC usable range be set in accordance with the usage of the vehicle  50  so that the battery  130  can be prevented from being kept in the over-charged state or the over-discharged state. 
     When the user performs the external charging using the electric power supplied from the power grid PG, the user has to pay the electricity cost for the charge amount (an amount of electric power used for the charging) to the power company. The electricity charge unit price (an electricity cost per unit amount of electric power) varies, depending on a time period. Thus, if the time period in which external charging is performed has a higher electricity charge unit price, an increased electricity cost may be charged to the user. In order to reduce the electricity cost charged to the user, preferably, the SOC usable range (the upper limit SOC) is set so that the charge amount is reduced during a time period that has a high electricity charge unit price. 
     When the external charging is performed in a time period in which a surplus amount power is generated from the electric power generated by the solar power generating equipment  13 , the above-described electricity cost charged to the user can be reduced by using the surplus power to perform the external charging. The CO2 emitted during generation of electric power to be supplied by the power grid PG, can also be reduced. From the perspective of reduction of CO2 emission, preferably, the SOC usable range (the upper limit SOC) is set in response to the presence or absence of the generation of surplus power so that a large amount of surplus power can be stored in the battery  130 . 
     Furthermore, in the power system  1 , the supply-demand balance of electric power may be adjusted, using a demand response (hereinafter, referred to as a “DR”). The DR is an approach for adjusting the demand for electric power by requesting, by a DR signal, a respective customer to reduce or increase the electric power demand. Note that the DR signal includes a DR signal requesting for reduction of the electric power demand (hereinafter, also referred to as a “negawatt-DR signal”), and a DR signal requesting for increase of the electric power demand (hereinafter, also referred to as a “posiwatt-DR signal”). 
     When the user of the vehicle  50  receives a DR signal, the user can charge or discharge an electric power from the vehicle  50  in accordance with a DR by using the EVSE  40 , thereby contributing to adjusting the demand for power. As a result, the user of the vehicle  50  can receive a predetermined incentive from the administrator of the power grid. In order for the user of the vehicle  50  to respond to the request to participate in the DR and receive an incentive, desirably, the SOC usable range is expanded. 
     As such, an SOC usable range that is good to achieve any one of the inhibition of the deterioration of the battery  130 , reduction of the electricity cost charged to the user, CO2 emission reduction, and power leveling may be determined, and the vehicle  50  may be demanded to meet this SOC usable range. 
     Thus, in the present embodiment, from the perspective stated above, the power system  1  calculates a good SOC usable range as an “expected range,” and outputs the expected range to the notification device for notifying the user of information. Then, in a situation where the user of the vehicle  50  uses the input device to set the SOC usable range, the notification device performs a process of guiding the user so that the SOC usable range is within the expected range. 
     &lt;Configuration of ECU  150  and Server  30 &gt; 
       FIG.  3    is a diagram showing a specific configuration of the ECU  150  and the server  30 . 
     As shown in  FIG.  3   , the ECU  150  includes an information management unit  501 , a charging and discharging control unit  502 , and a connector control unit  503 . These components are embodied by the processor  151  of  FIG.  1    executing programs stored in the storage device  153 . However, the present disclosure is not limited thereto. These components may be embodied by dedicated hardware components (electronic circuits). 
     Based on given information, the information management unit  501  updates the information in the storage device  153 . The output signal of the input device  160 , the results of detections by the various sensors mounted on the vehicle  50 , and the information received by the communications equipment  180  from outside the vehicle  50  are input to the information management unit  501 . 
     The storage device  153  stores information related to a usage history of the vehicle  50 . The usage history of the vehicle  50  includes travel histories such as previous travel routes and travel time of the vehicle  50 . The usage history of the vehicle  50  also includes execution history of previous external chargings and external power supplies. 
     The storage device  153  also stores information related to a usage schedule of the vehicle  50 . The usage schedule of the vehicle  50  includes a travel schedule, a charging schedule, and a DR schedule of the vehicle  50 . The travel schedule is information that indicates the travel start time, the travel end time, and the travel route that are scheduled by the user. The user can register the travel schedule with the storage device  153  through the input device  160 . The charging schedule is information indicating the charge schedule scheduled by the user. The user can register the charging schedule with the storage device  153  through the input device  160 . The DR schedule is information indicating a DR duration set to the vehicle  50 . 
     The information management unit  501  transmits the usage history and the usage schedule of the vehicle  50  to the server  30 . The information management unit  501  also obtains conditions of the vehicle  50  (e.g., a charging cable connection state, a connector locked/unlocked state, and the SOC of the battery  130 ), and transmits the obtained information to the server  30 . The charging cable connection state is information indicating whether the connector  43  of the charging cable  42  is connected to the inlet  110 . The connector locked/unlocked state is information indicating whether the connector  43  connected to the inlet  110  is in the locked state or the unlocked state. These information are transmitted to the server  30 , together with the vehicle ID. The transmission timing can be set arbitrarily. For example, the information management unit  501  may transmit predetermined information to the server  30  at predetermined cycles. Alternatively, the information management unit  501  may transmit the data stored in the storage device  153  to the server  30  at a predetermined time (e.g., at the end of travel of the vehicle  50  or upon connection with the connector  43 ). 
     If the user of the vehicle  50  is requested by the server  30  to participate in the DR, the information management unit  501  responds to the server  30  as to whether the user of the vehicle  50  approves the request. Specifically, if the communications equipment  180  receives the request, the information management unit  501  controls the notification device  170 , thereby encouraging the user of the vehicle  50  to reply to the request. Then, as the user enters in the input device  160  the information indicating whether the user approves the request, the information management unit  501  replies to the server  30  with a result of the user&#39;s decision. Note that in the above embodiment in which the request is transmitted to the user terminal  80 , the user terminal  80  may have a function of making the response. 
     The charging and discharging control unit  502  controls the charger-discharger  120 , thereby performing the charging and discharging control over the battery  130 , based on the SOC usable range of the battery  130 . If the vehicle  50  is ready for external charging and conditions for starting the external charging are met, the charging and discharging control unit  502  starts the external charging. If the vehicle  50  is ready for external power supply and conditions for starting the external power supply are met, the charging and discharging control unit  502  starts the external power supply. The conditions for starting the external charging and the external power supply may each be met when the user performs a predetermined start operation or upon arrival of a start time set by the user. 
     While the charging and discharging control over the battery  130  is, basically, performed according to programs implemented in the ECU  150 , it should be noted that during the DR duration, the charging and discharging control unit  502  is remotely controlled by the server  30 . Due to this, during the DR duration, the server  30  performs the charging and discharging control over the battery  130 . Note that the charging and discharging control unit  502  may be able to switch the remotely control between permitted and not permitted. The user may also be able to switch the remotely control between permitted and not permitted, through the input device  160 . The remote control by the server  30  over the charging and discharging control unit  502  may be permitted if the user of the vehicle  50  approves the request from the server  30  to participate in the DR. 
     The connector control unit  503  controls the connector locking device  111 , thereby performing a connector control (i.e., a lock/unlock control over the connector  43  connected to the inlet  110 ). Upon a request for the connector control (a connector lock request/a connector unlock request), the connector control unit  503  performs the connector control in accordance with the request. In the present embodiment, at least one of the input device  160  and the user terminal  80  receives a request for the connector control from the user. As the user enters a request for the connector control in the input device  160  or the user terminal  80 , the connector control unit  503  performs the connector control in accordance with the request input by the user. If the communications equipment  180  receives a request for the connector control from the server  30 , the connector control unit  503  performs the connector control, in accordance with the request received from the server  30 . 
     The controller  31  of the server  30  includes an information management unit  301 , a selection unit  302 , a request unit  303 , a setting unit  304 , a charging and discharging control unit  305 , and a connector control unit  306 . The components of the server  30  are embodied by the processor of the controller  31  of  FIG.  3    and programs executed by the processor (e.g., programs stored in the storage device  32 ). However, the present disclosure is not limited thereto. These components may be embodied by dedicated hardware components (electronic circuits). 
     The information management unit  301  manages information of each registered user (hereinafter, also referred to as “user information”), and information of each registered vehicle  50  (hereinafter, also referred to as “vehicle information”). The user information and the vehicle information are stored in the storage device  32 . 
     Identification information identifying a user (hereinafter, also referred to as a “user ID”) is given for each user. The information management unit  301  distinctly manages the user information by user ID. The user ID also functions as information identifying the user terminal  80  (a terminal ID). The user information contains a communication address of the user terminal  80  and the vehicle ID of the vehicle  50  belonging to the user. The user information also contains information indicating an amount of power generated by the solar power generating equipment  13  installed in the user&#39;s house  10 , which is received from the HEMS  15 . 
     The vehicle ID is identification information identifying the vehicle  50 . A vehicle ID is given for each vehicle  50 . The information management unit  301  distinctly manages the vehicle information by vehicle ID. The vehicle information contains a communication address of the communications equipment  180  mounted on the vehicle  50 , and the vehicle information (e.g., the usage history, the usage schedule, the charging cable connection state, and the connector locked/unlocked state of the vehicle  50 , the SOC of the battery  130 , and the power usage at the EVSE  40 ), which is received from a respective vehicle  50 . 
     Upon receiving electricity rate information from a higher-level server (not shown), the information management unit  301  saves the electricity rate information to the storage device  32 . The “electricity rate information” is information in which an electric power supply area, an electric power supply time, and an electricity rate are associated with each other. Upon receiving a DR request signal from the higher-level server, the information management unit  301  saves the DR request signal to the storage device  32 . 
     Based on the DR request signal, the selection unit  302  selects a DR vehicle. The selection unit  302  may select a DR vehicle, taking into account the charging cable connection state, the SOC of the battery  130 , and the usage schedule of the vehicle  50 . 
     Based on the DR request signal, the request unit  303  creates a charge and discharge command for each DR vehicle. The request unit  303  may create a charge and discharge command for the DR vehicle, taking into account the conditions of each DR vehicle. The information management unit  301  transmits the charge and discharge command created by the request unit  303  to each DR vehicle selected by the selection unit  302 . The process as described above allows a charge and discharge command to be transmitted to each DR vehicle from the server  30  during a DR duration indicated by the DR request signal. 
     Based on the SOC usable range of the battery  130 , the charging and discharging control unit  305  performs the charging and discharging control over the battery  130  mounted on the DR vehicle. The connector control unit  306  performs the connector control over the DR vehicle. 
     The setting unit  304  sets the SOC usable range for the battery  130 , in accordance with a user operation performed on the input device. The SOC usable range of the battery  130  is defined by the upper limit SOC and the lower limit SOC, as noted above. In the present embodiment, at least one of the input device  160  and the user terminal  80  can function as the input device that receives the SOC usable range input operation by the user of the vehicle  50 . Thus, the user is allowed to operate the input device  160  or the user terminal  80  to set at least one of the upper limit SOC and the lower limit SOC. 
     The setting unit  304  uses at least one of the vehicle information, the user information, and the electricity rate information, which are stored in the storage device  32 , to calculate the expected range of the SOC usable range (hereinafter, also referred to as an “SOC expected range”). The SOC expected range corresponds to a good SOC usable range that is demanded for the vehicle  50  to achieve any of the inhibition of deterioration of the battery  130 , reduction of the electricity cost charged to the user, CO2 emission reduction, and power leveling. 
     The SOC expected range is defined by an “upper limit expected value” indicating an expected value of the upper limit SOC and a “lower limit expected value” indicating an expected value of the lower limit SOC. The setting unit  304  calculates at least one of the upper limit expected value and the lower limit expected value, using a method described below. The setting unit  304  transmits the calculated SOC expected range to the notification device. 
     Using the SOC expected range received from the setting unit  304 , the notification device performs a process of guiding the user so that the SOC usable range is within the SOC expected range. Specifically, if the user terminal  80  is the input device that has received a setting request, the user terminal  80 , upon receiving the SOC expected range from the server  30 , controls the touch panel display, thereby performing the process of guiding the user so that the SOC usable range is within the SOC expected range. If the input device  160  is the input device that has received the setting request, the information management unit  501 , upon receiving the SOC expected range via the communications equipment  180 , controls the notification device  170 , thereby performing the process of guiding the user so that the SOC usable range is within the SOC expected range. Then, as the user finalizes the settings of the SOC usable range, the notification device transmits the finalized SOC usable range to the server  30 . 
     At the server  30 , the information management unit  301  stores the SOC usable range received from the notification device into the storage device  32 . The setting unit  304  sets the SOC usable range, in accordance with the SOC usable range finalized by the user. 
     &lt;Settings of SOC Usable Range of Battery  130 &gt; 
     Next, settings of the SOC usable range of the battery  130  is described. In the following, the user operates the user terminal  80  and sets the SOC usable range. In other words, the user terminal  80  is the “input device” and the “notification device.” Note that if the user operates the input device  160  in the vehicle  50  to set the SOC usable range, the input device  160  and the notification device  170  are the “input device” and the “notification device,” respectively. 
     (Example Configuration Screen of SOC Usable Range) 
       FIG.  4    is a diagram showing a first example of a configuration screen of the SOC usable range shown on the touch panel display of the user terminal  80 . As shown in  FIG.  4   , the configuration screen includes a settings display unit  200 , a settings bar  210 , display bars  212 ,  214 , and buttons  216 ,  218 . 
     The settings display unit  200  shows the current set value of the upper limit SOC indicating the upper limit of the SOC usable range, and the current set value of the lower limit SOC indicating the lower limit of the SOC usable range. Note that the EV distance (a distance that the vehicle  50  can travel with the electric power stored in the battery  130 ) where the SOC is at the upper limit SOC may be displayed together with the set value of the upper limit SOC, and the EV distance where the SOC is at the lower limit SOC may be displayed together with the set value of the lower limit SOC, as illustrated in the figure. Such an EV distance can be calculated from: the power storage calculated from the SOC; and the power consumption efficiency of the vehicle  50 . 
     The display bar  212  is displayed on the settings bar  210 , showing the current set value of the lower limit SOC by bar length. The display bar  214  is also displayed on the settings bar  210 , showing the current set value of the upper limit SOC by bar length. Furthermore, the current SOC is displayed on the settings bar  210 . 
     The user can set the upper limit SOC by performing an operation of touching the right end of the display bar  214  displayed on the settings bar  210  and sliding the display bar  214  in the left-right direction (corresponding to the direction of the arrow in the figure). The user can also set the lower limit SOC by performing an operation of touching and sliding the right end of the display bar  212  displayed on the settings bar  210  in the left-right direction. The set value is displayed in numeric value on the settings display unit  200 . Note that EV distances, corresponding to the set values of the upper limit SOC and the lower limit SOC, are also displayed in numeric value on the settings display unit  200 . 
     The button  216  allows the user to change at least one of the upper limit SOC and the lower limit SOC displayed on the settings display unit  200 . After performing the operation of touching the button  216 , the user can change the settings of at least one of the upper limit SOC and the lower limit SOC, using the settings bar  210 . 
     The button  218  is a button for completing the setup of the upper limit SOC and the lower limit SOC after the touch operation is performed on the button  216 . The user can finalize the settings of the upper limit SOC and the lower limit SOC by performing an operation of touching the button  218 . 
     As the button  218  is operated by the user, the user terminal  80  transmits the finalized set values of the upper limit SOC and the lower limit SOC to the server  30 . At the server  30 , the setting unit  304  sets an SOC usable range, in accordance with the set values of the upper limit SOC and the lower limit SOC received from the user terminal  80 . 
     When the SOC usable range is set, the user terminal  80  performs the process of guiding the user so that the SOC usable range is within the SOC expected range. Specifically, the upper limit expected value indicating the expected value of the upper limit SOC, and the lower limit expected value indicating the expected value of the lower limit SOC are displayed on the settings bar  210 . In the example of  FIG.  4   , the upper limit expected value and the lower limit expected value are displayed, overlaying the display bars  212  and  214 , respectively. Note that the upper limit expected value and the lower limit expected value, the EV distance where the SOC is at the upper limit expected value, and the EV distance where the SOC is at the lower limit expected value may be displayed in numeric value on the settings display unit  200 . 
     According to this, the user sets the upper limit SOC by performing an operation of touching and sliding the right end of the display bar  214 , while referring to the upper limit expected value. At this time, the upper limit expected value acts as a deterrent against the operation of sliding the right end of the display bar  214  in the right direction beyond the upper limit expected value. As a result, the user can be encouraged to set the upper limit SOC not exceeding the upper limit expected value. 
     Similarly, the user sets the lower limit SOC by performing the operation of touching and sliding the right end of the display bar  212  while referring to the lower limit expected value. At this time, the lower limit expected value acts as a deterrent against the operation of sliding the right end of the display bar in the left direction beyond the lower limit expected value. As a result, the user can be encouraged to set the lower limit SOC not falling behind the lower limit expected value. 
     The SOC expected range set by the server  30  is presented as such to the user on the user terminal  80 , thereby guiding the user to set the SOC usable range within the SOC expected range. However, since the settings of the SOC usable range is left up to the user operation, the user can set the upper limit SOC higher than the upper limit expected value and the lower limit SOC lower than the lower limit expected value. 
     As described above, according to the first example, the SOC usable range is set in accordance with the user&#39;s intent, while presenting the SOC expected range to the user, thereby combining the charging and discharging control desired by the user and the desire of the power system  1 . 
       FIG.  5    is a diagram showing a second example of the configuration screen of the SOC usable range. As shown in  FIG.  5   , the configuration screen includes a settings display unit  200 , settings bars  220 ,  222 , and buttons  216 ,  218 . The configuration screen of  FIG.  5    is the same as the configuration screen of  FIG.  4   , except for including the settings bars  220 ,  222 , in place of the settings bar  210  and the display bars  212 ,  214 . 
     The settings bar  220  shows the current set value of the lower limit SOC in numeric value. The user can set the lower limit SOC by performing an operation of touching and sliding the numeric value in the vertical direction (corresponding to the direction of the arrow in the figure). 
     The settings bar  222  shows the current set value of the upper limit SOC in numeric value. The user can set the upper limit SOC by performing an operation of touching and sliding the numeric value in the vertical direction. 
     In the example of  FIG.  5   , the lower limit expected value is displayed in numeric value on the settings bar  220 . Accordingly, similarly to the first example of  FIG.  4   , the user can be encourage to set the lower limit SOC not falling behind the lower limit expected value. In addition, the upper limit expected value is displayed in numeric value on the settings bar  222 . Accordingly, the user can be encouraged to set the upper limit SOC not exceeding the upper limit expected value. As such, even in the second example, the SOC usable range is set in accordance with the user&#39;s intent, while presenting the SOC expected range to the user, thereby combining the charging and discharging control desired by the user and the desire of the power system  1 . 
       FIG.  6    is a diagram showing a third example of the configuration screen of the SOC usable range. As shown in  FIG.  6   , the configuration screen includes a settings display unit  200 , a settings bar  210 , display bars  212 ,  214 , and buttons  216 ,  218 . 
     The basic configuration of the configuration screen of  FIG.  6    is the same as the configuration screen of  FIG.  4   . However, the configuration screen of  FIG.  6    differs from the configuration screen of  FIG.  4    in that the upper limit expected value and the lower limit expected value on the settings bar  210  are hidden on the configuration screen of  FIG.  6   . 
     Since the upper limit expected value is not presented to the user in the example of  FIG.  6   , the user can perform an operation of touching and sliding the right end of the display bar  212  in any manner to set the upper limit SOC. However, if the upper limit SOC set by the user is beyond the upper limit expected value, the user terminal  80  gives a notification to the user, encouraging to change the settings of the upper limit SOC. 
     Specifically, as shown in  FIG.  6   , the user terminal  80  displays on the configuration screen a message object  224  encouraging the user to change the settings of the upper limit SOC. For example, if the upper limit expected value is set, taking into account the electricity cost charged to the user, the message object  224  is displayed, showing “If you select this settings, the electricity cost may increase.” The content of the message object  224  is appropriately set, in accordance with an intent of the SOC expected range the vehicle  50  is demanded to have. 
     The configuration screen further shows a delete button  226  which accepts deletion of the message object  224 . The user can delete the message object  224  from the configuration screen by touching the delete button  226 . Once the message object  224  is deleted, the user can set the upper limit SOC again, by performing the operation of touching and sliding the right end of the display bar  212 . In other words, the user terminal  80  just gives a notification to the user, encouraging to change the settings of the upper limit SOC, and the settings of the upper limit SOC is left up to a user operation. Accordingly, the user can set the upper limit SOC higher than the upper limit expected value. 
     Although not shown in the figure, the user terminal  80  displays the message object  224  encouraging the user to change the settings of the lower limit SOC even if the lower limit SOC set by the user is less than the lower limit expected value. For example, if the lower limit expected value is set, taking into account the inhibition of deterioration of the battery  130 , the message object  224  is displayed, showing “If you select this settings, the battery  130  may be deteriorated.” 
     By touching the delete button  226  and deleting the message object  224  from the configuration screen, the user can perform the operation of touching and sliding the right end of the display bar  214  to set the lower limit SOC again. The user terminal  80  just gives a notification to the user, encouraging to change the setting of the lower limit SOC, and settings of the lower limit SOC is left up to a user operation. Accordingly, the user can set the lower limit SOC lower than the lower limit expected value. 
     As such, if the SOC usable range is out of the SOC expected range set by the server  30 , the user terminal  80  gives a notification to the user, encouraging to change the settings, thereby guiding the user to set the SOC usable range within the SOC expected range. However, since the settings of the SOC usable range is left up to the user operation, the user can set the upper limit SOC higher than the upper limit expected value and the lower limit SOC lower than the lower limit expected value. 
     As described above, according to the third example, the SOC usable range is set in accordance with the user&#39;s intent, while giving the user a notification encouraging the user to change the settings based on the SOC expected range, thereby combining the charging and discharging control desired by the user and the desire of the power system  1 . 
     (Flowchart) 
       FIG.  7    is a flowchart of a first example of the procedure of an SOC-usable-range setting process that is performed at the power system  1 . The flowchart shows the procedure of a setting process corresponding to the example configuration screens described with respect to  FIGS.  4  and  5   . The set of process steps illustrated in the flowchart are performed by the user terminal  80  and the server  30  if the user uses the user terminal  80  to set the SOC usable range. 
     In the figure, the process performed by the user terminal  80  is illustrated on the left, and the process performed by the server  30  is illustrated on the right. Each process step is implemented by software processing by the processor included in the user terminal  80  and software processing by the controller  31  of the server  30 . However, respective process steps may be implemented by hardware components such as LSIs (Large Scale Integration) which are disposed in the user terminal  80  and the server  30 . 
     In step (hereinafter, simply denoted as “S”)  01 , the user terminal  80  determines whether the user terminal  80  receives an SOC-usable-range setting request from the user of the vehicle  50 . S 01  is YES if, for example, the user launches an app preinstalled in the user terminal  80 , otherwise, it is NO. 
     If received an SOC-usable-range setting request (YES in S 01 ), the user terminal  80 , in S 02 , transmits the setting request to the server  30 . 
     Upon receiving the setting request from the user terminal  80 , the server  30 , in S 11 , calculates an SOC expected range, using at least one of the vehicle information, the user information, and the electricity rate information that are stored in the storage device  32 . In S 11 , the server  30  calculates at least one of the upper limit expected value and the lower limit expected value. In S 12 , the server  30  transmits the SOC expected range to the user terminal  80 . 
     In S 03 , the user terminal  80  shows the configuration screen of the SOC usable range on the touch panel display. In S 04 , the user terminal  80  shows the SOC expected range received from the server  30  on the configuration screen, together with the current upper limit SOC and the current lower limit SOC (see  FIGS.  4  and  5   ). At least one of the upper limit expected value and the lower limit expected value is displayed on the configuration screen. 
     In S 05 , the user terminal  80  determines whether the user terminal  80  receives an SOC usable range setting operation on the configuration screen. S 05  is YES if an operation of touching the button  216  and an operation of touching and sliding the right end of at least one of the display bars  212 ,  214  are performed on the configuration screen of  FIG.  4   . S 05  is YES if an operation of touching the button  216  and an operation of touching and sliding the numeric value of at least one of the settings bars  220 ,  222  are performed on the configuration screen of  FIG.  5   . 
     In S 06 , the user terminal  80  determines whether the user has completed the setup of the SOC usable range. S 06  is YES if an operation of touching the button  218  is performed on the configuration screens of  FIGS.  4  and  5   . The process steps of S 04  through S 06  are repeatedly performed until S 06  is YES. 
     If the user completes the setup of the SOC usable range (YES in S 06 ), the user terminal  80 , in S 07 , transmits to the server  30  the SOC usable range set by the user. Upon receiving the user setting value of the SOC usable range from the user terminal  80 , the server  30 , in S 13 , sets an SOC usable range in accordance with the user setting value. 
     In S 14 , the server  30  transmits the SOC usable range to the vehicle  50 . In S 15 , the server  30  and the vehicle  50  perform the charging and discharging control over the battery  130 , based on the SOC usable range of the battery  130 . 
       FIG.  8    is a flowchart of a second example of the procedure of the SOC-usable-range setting process that is performed at the power system  1 . The flowchart shows the procedure of a setting process corresponding to the example configuration screen described with respect to  FIG.  6   . The set of process steps illustrated in the flowchart are performed by the user terminal  80  and the server  30  if the user uses the user terminal  80  to set the SOC usable range. 
     In the figure, the process performed by the user terminal  80  is illustrated on the left, and the process performed by the server  30  is illustrated on the right. The flowchart shown in  FIG.  8    is the same as the flowchart of  FIG.  7   , except for not including S 04  and adding S 08  and S 09  to the process performed by the user terminal  80 . 
     In  FIG.  8   , the user terminal  80  does not display the SOC expected range received from the server  30  on the configuration screen. If the user terminal  80  determines that the SOC usable range setting operation performed on the configuration screen is received in S 05  (YES in S 05 ), the user, in S 08 , determines whether the SOC usable range is within the SOC expected range. S 08  is YES if the upper limit SOC is less than or equal to the upper limit expected value and the lower limit SOC is greater than or equal to the lower limit expected value, otherwise, it is NO. 
     If determined that the SOC usable range is out of the SOC expected range (NO in S 08 ), the user terminal  80 , in S 09 , notifies the user of a message encouraging the user to change the settings of the SOC usable range. For example, as shown in  FIG.  6   , the user terminal  80  displays on the configuration screen the message object  224  encouraging the user to change the settings of the SOC usable range. Note that the user having received the message object  224  can resume the SOC usable range setting operation by touching the delete button  226  displayed on the configuration screen and thereby deleting the message object  224 . 
     &lt;Calculation of SOC Expected Range&gt; 
     Next, calculation of the SOC expected range of the battery  130  is described. In the following, the server  30  (the setting unit  304 ) calculates the SOC expected range. 
     As noted above, the SOC expected range of the battery  130  is an SOC usable range of the battery  130  that the power system  1  requests from the vehicle  50 . The SOC expected range can be calculated from the perspectives of, for example, (1) inhibition of deterioration of the battery  130 , (2) reduction of the electricity cost charged to the user, (3) CO2 emission reduction, and (4) response to a request to participate in the DR. In the following, methods of calculation of the SOC expected range based on the respective perspectives are described. 
     (1) Inhibition of Deterioration of Battery  130   
     As a first mode, the setting unit  304  of the server  30  uses the vehicle information stored in the storage device  32  to predict the scope of use of the SOC of the battery  130  in the vehicle  50 . The vehicle information contains the usage schedules (the travel schedule, the charging schedule) of the vehicle  50 , and the usage histories (the travel history, the execution history of the external charging) of the vehicle  50 . 
     Upon receiving an SOC-usable-range setting request from the user, the setting unit  304 , using these information, predicts an amount of electric power that is required for the vehicle  50  to travel after the completion of the most-recent external charging until the next external charging. Specifically, using the travel schedule and the charging schedule, the setting unit  304  predicts an EV distance after the completion of the most-recent external charging until the next external charging. Then, from the predicted value of the EV distance and the power consumption efficiency of the vehicle  50 , the setting unit  304  calculates an amount of electric power that is required for the vehicle  50  to travel. Alternatively or additionally to the travel schedule and the charging schedule, using the travel history and the external charging execution history, the setting unit  304  may predict an amount of electric power that is required for the vehicle  50  to travel. 
     The setting unit  304  calculates the SOC expected range based on the predicted value of the amount of electric power that is required for the vehicle  50  to travel. The lower limit expected value is set higher than a threshold of the SOC that can cause the battery  130  to over-discharge an electric power. The upper limit expected value is calculated by adding the predicted amount of electric power to the lower limit expected value. 
     According to this, during a period after the completion of the most-recent external charging until the performance of the next external charging, the vehicle  50  is allowed to travel, using the electric power stored in the battery  130  to an extent that does not cause over-discharging of the electric power stored in the battery  130 . The shorter the EV distance to the next external charging, the lower the upper limit expected value. Setting the upper limit SOC in accordance with the upper limit expected value can inhibit the deterioration of the battery  130  from developing due to overcharge, while preventing a situation in which the vehicle  50  is disabled. 
     (2) Reduction of Electricity Cost Charged to User 
     As a second mode, the setting unit  304  of the server  30  calculates an SOC expected range, using the electricity rate information and the vehicle information stored in the storage device  32 . The electricity rate information is information in which an electric power supply area, an electric power supply time period, and an electricity rate are associated with each other. 
     The setting unit  304  refers to the electricity rate information, and the charging schedule and the external charging execution history, which are included in the vehicle information, to calculate the electricity rate during a time period in which external charging is performed. Based on the electricity rate, the setting unit  304  calculates the upper limit expected value. 
       FIG.  9    is a diagram schematically showing one example relationship between the electricity rate and the upper limit expected value. The upper part of  FIG.  9    shows a graph of the electricity rate over time of a day. The lower part of  FIG.  9    shows a graph of the upper limit expected value over time of the day. 
     In the example of  FIG.  9   , the electricity rate for a predetermined time period (time T 1  to time T 2 ) of a day is set higher than electricity rates of the other time periods. The time period from time T 1  to time T 2  is, for example, the time period from 7 AM to 11 PM. According to this, the electricity rate is inexpensive during late night hours from 11 PM to 7 AM next morning, which allows reduction of the electricity cost charged to the user. Therefore, in the example of  FIG.  9   , the upper limit expected value for the time period from time T 1  to time T 2  is lower than the upper limit expected values for the other time periods. 
     Upon receiving an SOC-usable-range setting request from the user, the setting unit  304  uses the charging schedule and/or the external charging execution history of the vehicle  50  to predict a time period in which the next external charging is performed. The setting unit  304  refers to the relationship shown in  FIG.  9    to calculate an upper limit expected value, based on the electricity rate during the time period in which the next external charging is performed. 
     According to this, when the external charging is performed during a time period in which the electricity rate is expensive, the upper limit expected value is low, and the power usage for the external charging can therefore be reduced, resulting in reduction of the electricity cost charged to the user. When the external charging is performed during a time period in which the electricity rate is inexpensive, the upper limit expected value is high, and more power can therefore be stored in the battery  130 , without increasing the electricity cost charged to the user. 
     (3) Reduction of CO2 Emission 
     As a third mode, the setting unit  304  of the server  30  calculates an SOC expected range, using the power generation information stored in the storage device  32 . The power generation information indicates an amount of power generated by the solar power generating equipment  13  installed in the user&#39;s house  10 . 
     The setting unit  304  refers to the power generation information, and the charging schedule and the external charging execution history included in the vehicle information, to predict an amount of power that is generated by the solar power generating equipment  13  during a time period in which external charging is performed. Note that the amount of power generated by the solar power generating equipment  13  varies, depending on a meteorological condition such as the weather, a time period, and a season, etc. 
     Specifically, upon receiving an SOC-usable-range setting request, the setting unit  304  predicts a time period in which the next external charging is performed, using the charging schedule and/or the external charging execution history of the vehicle  50 . The setting unit  304  also predicts an amount of power generated by the solar power generating equipment  13  during the time period in which external charging is performed, from the track record of the amounts of power generated by the solar power generating equipment  13 , and a meteorological condition (the predicted value) during the time period in which external charging is performed, etc. Based on the predicted amount of power generated by the solar power generating equipment  13 , the setting unit  304  calculates an upper limit expected value. 
       FIG.  10    is a diagram schematically showing one example relationship between the amount of power generated by the solar power generating equipment  13  and the upper limit expected value. In  FIG.  10   , the amount of power generated by the solar power generating equipment  13  is indicated on the horizontal axis, and the upper limit expected value is indicated on the vertical axis. 
     In  FIG.  10   , the upper limit expected value is set so as to increase with an increase of an amount of power generated by the solar power generating equipment  13 . The setting unit  304  refers to the relationship shown in  FIG.  10    to calculate the upper limit expected value, based on the predicted value of the amount of power that is generated by the solar power generating equipment  13  during the time period in which external charging is performed. 
     According to this, the upper limit expected value increases when the external charging is performed during a time period in which the solar power generating equipment  13  generates an increased amount of power generated. Therefore, if a surplus power is generated at the house  10 , the surplus power can be used for the external charging, without dumping it. In addition, when the electric power demand from the house  10  increases, the electric power stored in the vehicle  50  can be transmitted back to the house  10  through the EVSE  40 . Accordingly, CO2 emitted during generation of electric power to be supplied from the power grid PG can be reduced. 
     Note that, in the present embodiment, while the description has been given, with reference to setting the upper limit expected value in response to an amount of power generated by the solar power generating equipment  13  installed in the house  10 , the upper limit expected value may be set in response to a renewable energy ratio of the electric power supplied from the power grid PG. The “renewable energy ratio” is a ratio of an electric power that is generated using a renewable energy (solar energy, wind power energy, geothermal energy, etc.) to an overall electric power generated, the renewable energy having a low environmental impact. The electric power generated using the renewable energy emits little CO2. Owing to this, the higher the renewable energy ratio, the less the CO2 emitted during generation of electric power. 
     In this case, the setting unit  304  obtains, through a higher-level server, the information indicating the renewable energy ratio of the electric power supplied from the power grid PG, refers to the obtained information, the charging schedule and the external charging execution history of the vehicle  50 , and predicts a renewable energy ratio during a time period in which external charging is performed. The setting unit  304  sets the upper limit expected value so that the upper limit expected value increases with an increase of the predicted renewable energy ratio. 
     (4) Response to Request to Participate in DR 
     As a fourth mode, the setting unit  304  of the server  30  calculates an SOC expected range, using the DR schedule stored in the storage device  32 . The DR schedule is information that indicates a DR duration set to the vehicle  50 . 
     If the user of the vehicle  50  approves the request to participate in a DR, the setting unit  304 , upon receiving an SOC-usable-range setting request from the user, refers to the DR schedule and determines whether the vehicle  50  has a schedule to participate in a DR. If the vehicle  50  has a schedule to participate in a DR, the setting unit  304  calculates an SOC expected range so that the SOC expected range is greater than the default value of a predetermined SOC usable range. 
     For example, if the vehicle  50  has a schedule to participate in a posiwatt DR requesting for an increase of the electric power demand, the setting unit  304  sets the upper limit expected value higher than the default value of the upper limit SOC. If the vehicle  50  has a schedule to participate in a negawatt DR requesting for mitigation of power shortfall (e.g., reduction of the electric power demand, or backfeeding), the setting unit  304  sets the lower limit expected value lower than the default value of the lower limit SOC. 
     According to this, the charge amount by external charging can be increased in a posiwatt DR duration, thereby contributing to an increase of the electric power demand. The amount of power supplied by external power supply can be increased in a negawatt DR duration, thereby contributing to mitigation of the power shortfall by increasing the backfeeding. The contribution of the vehicle  50  to the adjustment of the supply and demand of the power grid can be enhanced by setting the SOC usable range, taking into account as such a request to participate in a DR. As a result, the user of the vehicle  50  can receive a large incentive from the administrator of the power grid. 
     As described above, in the present embodiment, if the SOC expected range desired by the power system  1  is output to the interface, the interface performs a process of guiding the user of the vehicle  50  so that the SOC usable range is within the SOC expected range in the situation where the user sets the SOC usable range. Since the user can be encouraged to set the SOC usable range so that the SOC usable range is within the SOC expected range, thereby combining the charging and discharging control desired by the user and the desire of the power system  1 . 
     OTHER EMBODIMENTS 
     (1) In the embodiments described above, the server  30  sets the SOC usable range in accordance with a user operation performed on a user interface where the interface is the user terminal  80 , or the input device  160  and the notification device  170  of the vehicle  50 . However, the vehicle  50  may set the SOC usable range. 
       FIG.  11    is a diagram showing a specific configuration of an ECU  150  included in a vehicle  50 , and a server  30 , according to another embodiment of the present disclosure. As shown in  FIG.  11   , the ECU  150  of the vehicle  50  differs from the ECU  150  of  FIG.  3    in that the ECU  150  includes a setting unit  504 . The server  30  differs from the server  30  of  FIG.  3    in that the server  30  does not have the setting unit  304 . 
     In the configuration example of  FIG.  11   , the storage device  153  of the vehicle  50  includes the electricity rate information, and information indicating an amount of power generated by the solar power generating equipment  13 , in addition to the information related to the usage history of the vehicle  50  and the information related to the usage schedule of the vehicle  50 . 
     Upon receiving an SOC-usable-range setting request from a user via a user terminal  80 , the setting unit  504  calculates an SOC expected range, using information stored in a storage device  153 . An information management unit  501  transmits the SOC expected range to a user terminal  80  via a communications equipment  180 . Note that if an input device  160  receives the setting request, the information management unit  501  outputs the SOC expected range to a notification device  170 . Upon receiving the SOC usable range set by the user from the user terminal  80  or the input device  160 , the setting unit  504  sets the SOC usable range in accordance with the user settings. 
     (2) In the embodiments described above, the server  30  sets the SOC usable range in accordance with a user operation performed on an interface where the interface is the user terminal  80 . However, the user terminal  80  may set the SOC usable range. 
       FIG.  12    is a diagram showing a specific configuration of a user terminal  80  according to another embodiment of the present disclosure. As shown in  FIG.  12   , the user terminal  80  includes a controller  800 , a communication device  802 , a touch panel display  804 , and a storage device  806 . The controller  800  includes a processor, and performs predetermined information processing and controls the communication device  802 . The storage device  806  is capable of saving various information. Besides programs (including apps) executed by the controller  31 , the storage device  806  stores information which are used in the program. The communication device  802  includes various communication I/Fs. The controller  800  communicates externally through the communication device  802 . 
     The controller  800  includes an information management unit  808  and a setting unit  810 . Upon receiving, from the vehicle  50 , the information related to the usage history of the vehicle  50 , the information related to the usage schedule of the vehicle  50 , the electricity rate information, and the information indicated the amount of power generated by the solar power generating equipment  13 , the information management unit  808  saves the received information to the storage device  806 . 
     If the touch panel display  804  receives an SOC-usable-range setting request from the user, the setting unit  810  calculates an SOC expected range, using the information stored in the storage device  806 . The information management unit  808  outputs the SOC expected range to the touch panel display  804 . Using the SOC expected range, the touch panel display  804  performs a process of guiding the user so that the SOC usable range is within the SOC expected range. Upon receiving the SOC usable range set by the user from the touch panel display  804 , the setting unit  810  sets an SOC usable range in accordance with the user settings. The information management unit  808  transmits the SOC usable range to the server  30  and the vehicle  50  via the communication device  802 . 
     Although the present disclosure has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present disclosure being interpreted by the terms of the appended claims.