Energy management device

Abstract

To perform energy management with a large economical merit while preventing a power storage device mounted on a vehicle from degrading.SOLUTION: An energy management device is configured to establish a charge / discharge plan for each of a stationary power storage device 110 and a power storage device 210 mounted on a vehicle 200. The energy management device establishes the charge / discharge plan such that charging of the power storage device 110 accompanied by power purchase is less likely to be executed as time elapses from the start of the charge / discharge plan and more likely to be executed as an electricity charge is lower, such that charging of the power storage device 210 accompanied by power purchase is more likely to be executed as time elapses from the start of the charge / discharge plan and more likely to be executed as the electricity charge is lower, and such that discharging of the power storage device 110 is executed when the electricity charge is higher than the electricity charge at the time of power purchase for charging of the power storage device 110.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an energy management device.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2012-196028 (Patent Document 1) discloses an energy management device that performs charge and discharge control of each of an in-vehicle battery and a stationary battery. In this device, when supplementing power from both the in-vehicle battery and the stationary battery to grid power, the stationary battery is preferentially discharged, and when charging the in-vehicle battery and the stationary battery, the in-vehicle battery is preferentially charged. Rapid charging at a large current is performed on the in-vehicle battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology described in Patent Document 1, the in-vehicle battery is preferentially charged. For this reason, the time during which the in-vehicle battery is in a high state of charge (SOC) tends to be long. The in-vehicle battery is likely to deteriorate when in a high SOC state. Also, deterioration of the in-vehicle battery is likely to be promoted by rapid charging. In Patent Document 1, deterioration of the in-vehicle battery is not considered.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to perform energy management with a large economic merit while suppressing deterioration of a power storage device mounted on a vehicle.

Means for Solving the Problems

[0006] An energy management device according to an aspect of the present disclosure is configured to formulate a charge-discharge plan for each of a stationary first power storage device and a second power storage device mounted on a vehicle. The energy management device formulates the charge-discharge plan such that charging of the first power storage device involving power purchase becomes less likely to be executed as time elapses from the start of the charge-discharge plan and becomes more likely to be executed as the electricity rate is lower, and charging of the second power storage device involving power purchase becomes more likely to be executed as time elapses from the start of the charge-discharge plan and becomes more likely to be executed as the electricity rate is lower, and discharging of the first power storage device is executed when the electricity rate is higher than the electricity rate at the time of power purchase for charging the first power storage device.

Advantages of the Invention

[0007] According to the present disclosure, it becomes possible to perform energy management with a large economic merit while suppressing deterioration of the power storage device mounted on the vehicle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0010] FIG. 1 is a diagram showing an energy management system according to this embodiment. Referring to FIG. 1, this system includes a building 100, a vehicle 200, a mobile terminal 300, and a power grid PG. In this embodiment, the building 100 is a residence. However, the building 100 may be other buildings such as a factory or a commercial facility. The power grid PG includes a power network, power generation equipment, and power transformation equipment. The power network is constructed by power transmission and distribution equipment. Users of the building 100 and the vehicle 200 (for example, residents of the building 100) purchase electricity (buy electricity) from an energy service provider (ESP) such as an electric power company. The electricity rate changes from moment to moment. The electricity purchased by the user is supplied to the building 100 through the power grid PG.

[0011] The building 100 includes a power storage device 110 (first power storage device), an EVSE (Electric Vehicle Supply Equipment) 120, a solar power generation facility 130, a PCS (Power Conditioning System) 140, and an EMS (Energy Management System) 150. The power storage device 110 is a stationary power storage device. The power storage device 110 and the EVSE 120 are installed within the site (outdoor) of the building 100. The EMS 150 corresponds to an example of the "energy management device" according to the present disclosure.

[0012] The EVSE 120 is electrically connected to the PCS 140. In addition, the EVSE 120 is configured to be electrically connectable to the vehicle 200 via, for example, a charging cable. For example, when the tip (connector) of the charging cable connected to the EVSE 120 is connected to the inlet (power receiving port) of the vehicle 200 (plugged in), the EVSE 120 and the vehicle 200 are electrically connected. The connector of the charging cable is configured to be detachable from the inlet of the vehicle 200. Hereinafter, the state where the vehicle 200 is connected to the EVSE 120 is referred to as a "vehicle connected state", and the state where the vehicle 200 is not connected to the EVSE 120 is referred to as a "vehicle detached state".

[0013] Vehicle 200 is provided with a power storage device 210 (second power storage device). The power storage device 210 corresponds to an in-vehicle battery. Vehicle 200 is configured to be able to run using the power output from the power storage device 210. Vehicle 200 may be a battery electric vehicle (BEV) without an internal combustion engine, or may be a PHEV (plug-in hybrid vehicle) with an internal combustion engine. The mobile terminal 300 is carried by the user of the vehicle 200. The mobile terminal 300 is, for example, a smartphone equipped with a touch panel display. However, a wearable device, a portable game machine, an electronic key, etc. can also be adopted as the mobile terminal 300.

[0014] The solar power generation facility 130 is, for example, a solar panel installed on the roof of the building 100. The solar power generation facility 130 outputs the PV power generated by sunlight to the PCS 140. PV means "Photovoltaics". The PCS 140 is electrically connected to the power grid PG. The power grid PG supplies AC power (for example, single-phase or three-phase AC power) to the PCS 140. The amount of power supplied from the power grid PG to the PCS 140 is sequentially measured by the smart meter SM. The smart meter SM may transmit the measured amount of power to each of the EMS 150 and the server 500 of the ESP. The PCS 140 includes various circuits for processing related to power conditioning (for example, power conversion and input / output adjustment). The PCS 140 converts the AC power received from the power grid PG into DC power according to an instruction from the EMS 150, and outputs the DC power to at least one of the EVSE 120 and the power storage device 110. The power storage device 110 is charged by the DC power from the PCS 140. The EVSE 120 charges the power storage device 210 using the DC power received from the PCS 140. The EMS 150 executes charge / discharge control of each of the power storage devices 110 and 210 in cooperation with the PCS 140, the EVSE 120, and the ECU (Electronic Control Unit) of the vehicle 200.

[0015] EMS150 may include a computer. EMS150 includes, for example, a processor 151 and a storage device 152. EMS150 is configured to be able to acquire the measured values of the SOC of each of the power storage devices 110 and 210. SOC (State Of Charge) indicates the state of charge, for example, the ratio of the current state of charge to the state of charge at full charge. The measured values of SOC are sequentially acquired and stored in the storage device 152. The storage device 152 is configured to be able to store the stored information. Also, by the processor 151 executing the program stored in the storage device 152, the control described below is executed. However, these controls may be executed only by hardware (electronic circuits) without using software.

[0016] EMS150 executes the processing flow (S11 to S14 and S20) shown in the flowchart in FIG. 1. "S" in the flowchart means step. For example, when the vehicle 200 changes from the vehicle detachment state (driving state) to the vehicle connection state (parking state), EMS150 starts the said processing flow. However, the start condition of the processing flow is arbitrary and may be established by an event other than the plugin related to the vehicle 200 (such as system startup).

[0017] In S11, EMS150 determines whether or not a request for energy management (hereinafter also referred to as "energy management") has been received from the user. For example, EMS150 sends a notification prompting the user to select whether or not they desire energy management to the mobile terminal 300. When receiving the notification from EMS150, the mobile terminal 300 displays a screen prompting the user for the above selection, and in response to the user's input (selection) to the screen, sends a reply indicating whether or not the user desires (requests) energy management. Based on the reply from the mobile terminal 300, EMS150 determines whether or not a request for energy management has been received from the user.

[0018] When the energy management request is not received (NO in S11), in S20, the EMS 150 executes charge control of the power storage device 210 (hereinafter referred to as "normal charge control"). The normal charge control is charge control for securing energy (electric power) for the running of the vehicle 200 in the power storage device 210. In the normal charge control, the electricity rate is not considered. For example, the power storage device 210 is charged until the SOC of the power storage device 210 reaches a predetermined SOC value (for example, the SOC value indicating full charge). Then, when the charging is completed, the processing flow ends.

[0019] When the energy management request is received (YES in S11), in S12, the EMS 150 acquires electricity rate information indicating the transition of the predicted value of the electricity rate in a future predetermined period (hereinafter referred to as "target period"). The line L3 in FIG. 1 shows an example of the transition of the predicted value of the electricity rate in the target period. The EMS 150 may acquire the electricity rate information from the server 500.

[0020] In the subsequent S13, the EMS 150 formulates a charge / discharge plan for each of the power storage devices 110 and 210 using the above electricity rate information. Subsequently, in S14, the EMS 150 executes charge / discharge control of each of the power storage devices 110 and 210 according to the formulated charge / discharge plan.

[0021] Specifically, the EMS 150 formulates the first plan and the second plan for the target period such that the evaluation function represented by the formula "evaluation function (t) = first plan (t) × {-electricity charge (t) + first coefficient (t)} + second plan (t) × {-electricity charge (t) + second coefficient (t)}" is minimized at S13. (t) in the formula means a function of time. The first plan and the second plan correspond to the charge-discharge plans of the power storage devices 110 and 210, respectively. Each of the first plan and the second plan indicates charge-discharge power with the discharge side being positive (+) and the charge side being negative (-). The fact that the evaluation function becomes larger on the negative side means that the evaluation function becomes smaller. The larger the first coefficient becomes, the easier it is to execute the charge of the power storage device 110, and the more difficult it is to execute the discharge of the power storage device 110. The larger the second coefficient becomes, the easier it is to execute the charge of the power storage device 210, and the more difficult it is to execute the discharge of the power storage device 210. Also, the lower the electricity charge becomes, the easier it is to execute the charge of each of the power storage devices 110 and 210 involving power purchase. The charge involving power purchase is a charge by the power supplied from the power grid PG. Regarding the charge without power purchase (for example, the charge by self-generation), the electricity charge may be regarded as "0" (free). Furthermore, the higher the electricity charge becomes, the easier it is to execute the discharge of each of the power storage devices 110 and 210. As a result, the discharge of the power storage device 110 is executed when the electricity charge is higher than the electricity charge at the time of power purchase for charging the power storage device 110. The discharged power may be sold or used in the building 100.

[0022] In FIG. 1, line L1 and line L2 respectively show an example of the transition of the first coefficient and the second coefficient during the target period. The start time of the target period corresponds to the start point of the charge-discharge plan. In this example, each of the first coefficient and the second coefficient changes toward the reference value (for example, 0.5 yen / kWh) at the end time of the target period. The value of the first coefficient at the start time of the target period (for example, 1.5 yen / kWh) is higher than the reference value, and approaches the reference value with a negative first change rate (<0). The value of the second coefficient at the start time of the target period (for example, 0 yen / kWh) is lower than the reference value, and approaches the reference value with a positive second change rate (>0). When comparing the change rates (the slopes of the graphs) of the respective coefficients with respect to time, the slope (the first change rate) of the first coefficient is greater than the slope (the second change rate) of the second coefficient. Also, the first coefficient (line L1) is greater than the second coefficient (line L2). According to such first and second coefficients, the power storage device 110 is more likely to be charged when the electricity price is low in the first half of the target period, and the power storage device 110 is more likely to be discharged when the electricity price is high in the second half of the target period. The user can obtain a profit from the difference between the electricity price at the time of charging and the electricity price at the time of discharging (hereinafter referred to as "value difference").

[0023] As described above, the EMS 150 makes the charging of the power storage device 110 (the stationary first power storage device) involving power purchase less likely to be executed as time passes from the start of the charge-discharge plan and more likely to be executed as the electricity price is lower, and makes the charging of the power storage device 210 (the second power storage device mounted on the vehicle) involving power purchase more likely to be executed as time passes from the start of the charge-discharge plan and more likely to be executed as the electricity price is lower, and makes the discharging of the power storage device 110 be executed when the electricity price is higher than the electricity price at the time of power purchase for charging the power storage device 110, and formulates a charge-discharge plan.

[0024] According to the above configuration, it is possible to pursue the economic efficiency of consumers including power purchase, power selling, and self-consumption by using the resources of both energy storage devices 110 and 210. Also, the charging of energy storage device 110 is advanced (shifted forward) in time series, and the charging of energy storage device 210 is delayed (shifted backward) in time series. More specifically, energy storage device 110 is likely to be charged at the initial stage of the charge-discharge plan, and becomes less likely to be charged as the end of the charge-discharge plan approaches. On the other hand, energy storage device 210 is less likely to be charged at the initial stage of the charge-discharge plan, and becomes more likely to be charged as the end of the charge-discharge plan approaches. Therefore, for pursuing profit due to the price difference, energy storage device 110 is preferentially used over energy storage device 210. The greater the slopes (rates of change) of the coefficients indicated by lines L1 and L2, the more easily the corresponding energy storage device is used for pursuing profit due to the price difference. Also, since the high SOC holding time of energy storage device 210 is shortened, calendar degradation of energy storage device 210 is suppressed. Also, at the initial stage of the target period, by suppressing the charging of energy storage device 210, the discharge amount of energy storage device 210 becomes less than the discharge amount of energy storage device 110. Thereby, cycle degradation of energy storage device 210 is suppressed. According to the above configuration, it becomes possible to perform energy management with a large economic merit while suppressing the degradation of the energy storage device mounted on the vehicle.

[0025] FIG. 2 is a diagram showing an example of charge-discharge control executed in S14 of FIG. 1. In FIG. 2, line L11 indicates the state of vehicle 200 (vehicle connection state / vehicle disconnection state), line L12 indicates the electricity rate, and line L13 indicates surplus PV power. "Parking" in the figure means the vehicle connection state. The surplus PV power is the portion of the PV power generated by the solar power generation facility 130 that exceeds the power (required power) used in the building 100. Lines L21 and L22 indicate the SOCs of energy storage devices 110 and 210, respectively. Lines L31 and L32 indicate the charge-discharge powers of energy storage devices 110 and 210, respectively. In S14 of FIG. 1, since charge-discharge control of each of energy storage devices 110 and 210 is executed according to the charge-discharge plan, the charge-discharge powers indicated by lines L31 and L32 generally match the charge-discharge plans of energy storage devices 110 and 210, respectively.

[0026] Referring to FIG. 2, in this example, when one of the power storage devices 110 and 210 is performing charge and discharge (charging or discharging), the other does not perform charge and discharge. Specifically, during a time period when the electricity rate is low or when surplus PV power is generated, charging of the power storage device 110 is preferentially executed over charging of the power storage device 210. Then, when the power storage device 110 is fully charged, charging of the power storage device 210 is executed instead of charging of the power storage device 110. Also, during a time period when no surplus PV power is generated and the electricity rate is high, discharging of the power storage device 110 is executed. The discharge amount of the power storage device 210 is less than the discharge amount of the power storage device 110.

[0027] Regarding the formulation of the charge and discharge plan, conditions that take precedence over the evaluation function may be set. For example, the EMS 150 may acquire the scheduled departure time (the time when the vehicle 200 is scheduled to be in a vehicle departure state) and set a target SOC value at the scheduled departure time. The EMS 150 may formulate a charge and discharge plan (the first plan and the second plan) such that the evaluation function is minimized on the premise that the SOC of the power storage device 210 at the scheduled departure time satisfies the condition of being equal to or higher than the target SOC value (a predetermined prerequisite). FIG. 3 is a diagram showing charge and discharge control according to the charge and discharge plan formulated in this way. The parameters indicated by the lines L11, L12, L13, L21, L22, L31, and L32 in FIG. 3 are the same as those in FIG. 2.

[0028] Referring to FIG. 3, when the vehicle 200 is in a vehicle-disconnected state (driving state), the power storage device 210 is out of the control of the EMS 150. Therefore, each of the SOC (line L22) of the power storage device 210 and the charge / discharge power (line L32) of the power storage device 210 becomes a constant value (for example, zero). When the vehicle 200 changes from the vehicle-disconnected state (driving state) to the vehicle-connected state (parking state) (see line L11), as shown by line L22, the EMS 150 recognizes the SOC of the power storage device 210 at that time. Then, when the scheduled departure time approaches, charging of the power storage device 210 is started so as to increase the SOC of the power storage device 210 to the target SOC value. On the other hand, for the power storage device 110, charge / discharge control for obtaining profit due to the value difference is executed. The EMS 150 may formulate a charge / discharge plan as shown in FIG. 3, for example, on Thursday, Friday, or Saturday.

[0029] Note that the charging method is not limited to contact charging (plug-in charging), and non-contact charging may also be used. A vehicle performing non-contact charging may be regarded as being in a state corresponding to the above-described "vehicle-connected state" when the alignment between the power transmission unit on the power supply facility side and the power reception unit on the vehicle side is completed.

[0030] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the description of the above embodiments but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Reference Numerals

[0031] 100 Building, 110 Power storage device, 150 EMS, 200 Vehicle, 210 Power storage device.

Claims

【Claim 1】 An energy management device that formulates a charge / discharge plan for each of a stationary first power storage device and a second power storage device mounted on a vehicle, such that charging of the first power storage device involving power purchase becomes less likely to be executed as time passes from the start of the charge / discharge plan and becomes more likely to be executed as the electricity rate is lower, and such that charging of the second power storage device involving power purchase becomes more likely to be executed as time passes from the start of the charge / discharge plan and becomes more likely to be executed as the electricity rate is lower, and such that discharging of the first power storage device is executed when the electricity rate is higher than the electricity rate at the time of power purchase for charging the first power storage device, the energy management device formulating the charge / discharge plan.

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