Patent Description:
It is known that the charge/discharge characteristics of a battery used in an electric vehicle, such as the charge and discharge speeds, deteriorate in a low temperature environment (for example, <NUM> or less). <CIT> proposes a method of reducing deterioration of the charge/discharge characteristic by adjusting the temperature of a battery using a heater when charging/discharging the battery in a low temperature environment.

In recent years, a VPP (Virtual Power Plant) system has received attention, which controls a power demand by a resource aggregator that brings the power units (power sources and resources) of a plurality of customers together to satisfy a power demand request in a power market. In such a VPP system, it is desirable to perform, as planned, the operation (demand response) of the power unit according to the request of the power demand in the power market.

However, if the method of heating the battery of a power unit by a heater, as described in <CIT>, is applied in the VPP system, the interests of customers may be harmed by the power cost of the heater, or it may be difficult to do the demand response as planned because of the time needed for battery temperature adjustment. <CIT> discloses charging the battery in a time period in which the degree of deterioration influence of the battery is low, but no temperature adjuster configured to adjust the temperature of the battery, <CIT> discloses warming up the battery of the vehicle by turning on the ignition of the vehicle on a predetermined time before the departure reservation time, but, does not teach controlling the temperature adjuster such that the temperature of the battery reaches the target temperature at the start timing requested for starting the charge or discharge of the battery in the demand response plan.

The present invention in its first aspect provides a control apparatus as specified in claims <NUM> to <NUM>. The control apparatus is configured to control a power unit, wherein the power unit comprises a battery, and a temperature adjuster configured to adjust a temperature of the battery to a target temperature at the time of charge or discharge of the battery. The control apparatus may calculate, based on information concerning a demand response plan used to adjust a power demand and supply, an incentive obtained by charge or discharge of the battery by the demand response plan and a power cost needed to adjust the temperature of the battery to the target temperature by the temperature adjuster at the time of charge or discharge of the battery, and may control, in a case where the incentive is larger than the power cost, controls the power unit to execute charge or discharge of the battery by the demand response plan.

According to these features, it is possible to reduce a loss for a customer caused by adjusting the temperature of the battery and appropriately ensure interests (incentive) obtained by the charge/discharge of the battery by the demand response (DR) plan.

The control apparatus may control the temperature adjuster based on the information concerning the demand response plan such that the temperature of the battery reaches the target temperature until a start timing of the charge or discharge of the battery by the demand response plan.

According to these features, since the charge/discharge characteristic of the battery can be set to a predetermined value or more until the start timing of charge/discharge, charge/discharge of the battery according to the demand response (DR) plan can efficiently be executed.

According to the features of claim <NUM>, since the temperature of the battery is made to reach the target temperature at the start timing of the charge or discharge of the battery, it is possible to reduce the power cost needed to maintain the temperature of the battery at the target temperature after adjusted to the target temperature.

Further, in a case where the incentive is not more than the power cost, the control apparatus may not execute the charge or discharge of the battery by the demand response plan.

According to this embodiment, if the interests (incentive) cannot be obtained when the temperature of the battery is adjusted, the demand response is not executed, thereby reducing a loss for a customer.

According to the features of claim <NUM>, since the charge/discharge characteristic of the battery can be set to a predetermined value or more until the start timing of charge/discharge, charge/discharge of the battery according to the demand response (DR) plan can efficiently be executed.

According to the features of claim <NUM>, it is possible to provide a VPP system (V2G system) using at least one of an electric vehicle and a stationary battery.

The present invention in its second aspect provides a management server as specified in claim <NUM>.

According to the features of claim <NUM>, centralized control of a plurality of power units (an electric vehicle and a stationary battery) by the management server can be performed. If a plurality of power units are controlled, and both the electric vehicle and the stationary battery exist as the power units, centralized control by the management server is effective.

The present invention in its third aspect provide a control method as specified in claims <NUM>.

The present invention in its fourth aspect provide a storage medium as specified in claim <NUM>.

Note that the following embodiments are not intended to limit the scope of the claimed invention, and limitation is not made to an invention that requires all combinations of features described in the embodiments. Two or more of the multiple features described in the embodiments may be combined as appropriate. Furthermore, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.

An embodiment of the present invention will be described. <FIG> is a block diagram showing the overall arrangement of a VPP (Virtual Power Plant) system <NUM> according to this embodiment. In this embodiment, as the VPP system <NUM>, a V2G (Vehicle to Grid) system will be exemplified. The VPP system shown in <FIG> includes a power supplier <NUM>, an aggregator (management server) <NUM>, a charge/discharge control apparatus <NUM>, and a power unit <NUM>. In the example shown in <FIG>, a feeding path is indicated by a block arrow, and a communication path of information or data is indicated by a dashed arrow. Communication of information or data can be either wired or wireless.

The power supplier <NUM> is, for example, an electricity retailer or an electricity transmission and distribution utility, which supplies power to a plurality of customers via the power system network <NUM>. A customer means a facility itself, such as a home or a factory that receives a VPP service, and in this embodiment, can include the power unit <NUM>, and the charge/discharge control apparatus <NUM> that controls charge/discharge of the battery of the power unit <NUM>.

The aggregator <NUM> is located between the power supplier <NUM> and the customers and provides the VPP service to the customers. For example, the aggregator <NUM> can function as a management server that integrates/controls the energy management systems of a plurality of customers (power units <NUM>) in a predetermined region via a network <NUM> (EMS network) and constructs the VPP system. The aggregator <NUM> acquires the operation plan of the power units <NUM> according to a request of a power demand in a power market from the power supplier <NUM> via the network <NUM>, and manages charge/discharge of the battery of each power unit <NUM> in accordance with the operation plan. The operation plan of the power units <NUM>, which is used to adjust the power demand and supply in the power market, is also called a demand response plan which will also be referred to as a "DR plan" hereinafter.

Here, the demand response (DR) includes a "down DR" and an "up DR". The "down DR" means keeping the demand and supply balance of power by suppressing power consumption of customers or performing discharge from the batteries of customers to the power system network <NUM>, and is also called negawatt trading. On the other hand, the "up DR" means keeping the demand and supply balance of power by increasing power consumption of customers, and is also called posiwatt trading.

The charge/discharge control apparatus <NUM> can be an apparatus that manages, as the power unit <NUM>, a detachable battery such as a battery mounted in an electric vehicle (EV) or a battery used as a power supply of a home, and controls charge/discharge (charge and/or discharge) of the battery. For example, the charge/discharge control apparatus <NUM> stores an electric vehicle (EV) including a battery as the power unit <NUM>, and controls charge/discharge of the battery of the electric vehicle with respect to the power system network <NUM>. Other than the electric vehicle (EV), the charge/discharge control apparatus <NUM> may store a fuel cell vehicle (FCV) or a vehicle with a power generation unit such as a range extender and control discharge of electricity generated in these vehicles. In this embodiment, an electric vehicle (EV) including a battery will be exemplified as the power unit <NUM>, and the electric vehicle will sometimes be referred to as the "electric vehicle <NUM>" hereinafter.

The arrangements of the aggregator <NUM>, the charge/discharge control apparatus <NUM>, and the electric vehicle <NUM> will be described next with reference to <FIG>. Note that the arrangement of the charge/discharge control apparatus <NUM> shown in <FIG> can be a computer capable of executing the present invention related to a program.

<FIG> is a block diagram showing an example of the arrangement of the aggregator <NUM> (management server). The aggregator <NUM> includes, for example, a CPU <NUM>, a storage unit <NUM>, a memory <NUM>, and a communication unit <NUM>, and the units are communicably connected to each other via a system bus <NUM>. The CPU <NUM> comprehensively controls the aggregator <NUM> by, for example, reading out a program stored in the storage unit <NUM> to the memory <NUM> and executing it. The storage unit <NUM> stores not only basic programs and data used by the aggregator <NUM> to operate but also information and data acquired from the power supplier <NUM> and each customer (for example, the user of each electric vehicle <NUM>). The communication unit <NUM> is an interface that enables communication with the network <NUM>. In this embodiment, the CPU <NUM> of the aggregator <NUM> acquires information <NUM> (to be also referred to as the "DR plan information <NUM>" hereinafter) concerning a DR plan from the power supplier <NUM> by the communication unit <NUM> via the network <NUM>, and stores the acquired DR plan information <NUM> in the storage unit <NUM>. Also, the CPU <NUM> transmits the DR plan information <NUM> to the charge/discharge control apparatus <NUM>, and manages the charge/discharge control apparatus <NUM> based on the DR plan information.

<FIG> is a block diagram showing an example of the arrangement of the charge/discharge control apparatus <NUM>. The charge/discharge control apparatus <NUM> includes, for example, a CPU <NUM>, a storage unit <NUM>, a memory <NUM>, a charge/discharge connector <NUM>, and a communication unit <NUM>, and the units are communicably connected to each other via a system bus <NUM>. The CPU <NUM> comprehensively controls the charge/discharge control apparatus <NUM> by, for example, reading out a program stored in the storage unit <NUM> to the memory <NUM> and executing it. The storage unit <NUM> stores programs and data used to control charge/discharge of a battery <NUM> of the electric vehicle <NUM>. The charge/discharge connector <NUM> is connected to a charge/discharge connector <NUM> of the electric vehicle <NUM> via a cable to charge/discharge the battery <NUM> of the electric vehicle <NUM>. The communication unit <NUM> is an interface that enables communication with the network <NUM>. In this embodiment, the CPU <NUM> acquires DR plan information from the aggregator <NUM> (or the power supplier <NUM>) by the communication unit <NUM> via the network <NUM>, and stores the acquired DR plan information in the storage unit <NUM>. The CPU <NUM> then controls charge/discharge of the battery of the electric vehicle <NUM> based on the DR plan information.

<FIG> is a block diagram showing an example of the arrangement of the electric vehicle <NUM> serving as a power unit. The electric vehicle <NUM> includes an ECU (Electronic Control Unit) <NUM>, a motor <NUM>, the battery <NUM>, the charge/discharge connector <NUM>, and a communication unit <NUM>, and the units are communicably connected to each other via a system bus <NUM>. The ECU <NUM> can include a processor represented by a CPU, a storage device such as a semiconductor memory, an interface to an external device, and the like. The motor <NUM> is driven by the power of the battery <NUM> and generates the driving force of the electric vehicle <NUM>. The battery <NUM> is a storage battery that stores power to be supplied to the motor <NUM>, and charge/discharge is controlled by the charge/discharge control apparatus <NUM>. The charge/discharge connector <NUM> is connected to the charge/discharge connector <NUM> of the charge/discharge control apparatus <NUM> via a cable to charge/discharge the battery <NUM>. The communication unit <NUM> is an interface that enables communication with the network <NUM>.

The electric vehicle <NUM> according to this embodiment is provided with a temperature adjustment unit (temperature adjuster) <NUM> that adjusts the temperature of the battery <NUM>, and a measurement unit <NUM> that measures the temperature of the battery <NUM>. It is known that the charge/discharge characteristics of the battery <NUM> in the electric vehicle <NUM>, such as the charge/discharge speed (the charge speed and the discharge speed) and the battery capacity generally deteriorate in a low temperature environment (for example, <NUM> or less). Hence, the electric vehicle <NUM> according to this embodiment is provided with the temperature adjustment unit <NUM> that adjusts the temperature of the battery <NUM>, as shown in <FIG>. The temperature adjustment unit <NUM> is, for example, a heater attached to the battery <NUM> to heat (warm) the battery <NUM>. Based on the temperature of the battery <NUM> measured by the measurement unit <NUM>, the temperature of the battery <NUM> can be adjusted such that the temperature of the battery <NUM> becomes a target temperature. When the temperature adjustment unit <NUM> adjusts the temperature of the battery <NUM> to the target temperature in this way, charge/discharge of the battery <NUM> by the charge/discharge control apparatus <NUM> can efficiently be performed. For example, as shown in <FIG>, the target temperature can be set to an arbitrary temperature within the temperature range in which the charge/discharge characteristic has a value equal to or larger than a predetermined value (target value) in the relationship between the temperature acquired in advance by experiments and the like and the charge/discharge characteristic of the battery <NUM>.

Here, in the above-described VPP system <NUM>, if temperature adjustment of the battery <NUM> by the temperature adjustment unit <NUM> is applied when charging/discharging the battery <NUM>, for example, a loss may occur due to the power cost needed to adjust the temperature of the battery <NUM> by the temperature adjustment unit <NUM>, or it may be difficult to do the demand response (DR) as planned because of the time needed for the temperature adjustment of the battery <NUM>. Hence, the charge/discharge control apparatus <NUM> according to this embodiment calculates, based on the DR plan information, an incentive obtained by the charge/discharge (charge or discharge) of the battery <NUM> by the DR plan and the power cost needed to adjust the temperature of the battery <NUM> to the target temperature by the temperature adjustment unit <NUM> at the time of charge/discharge of the battery <NUM>, and determines, based on the calculation result, whether to charge/discharge the battery <NUM>. In addition, the charge/discharge control apparatus <NUM> controls, based on the DR plan information, the temperature adjustment unit <NUM> such that the temperature of the battery <NUM> becomes the target temperature until the timing of starting charge/discharge (charge or discharge) of the battery <NUM> by the DR plan.

The control procedure of charge/discharge of the battery <NUM> of the electric vehicle <NUM> by the charge/discharge control apparatus <NUM> will be described next. <FIG> and <FIG> are flowcharts showing the control procedure of charge/discharge of the battery <NUM> of the electric vehicle <NUM> by the charge/discharge control apparatus <NUM>. Each step of the flowcharts shown in <FIG> and <FIG> can be executed by the CPU <NUM> of the charge/discharge control apparatus <NUM>. In addition, "charge/discharge" in the following description is intended for one of charge to the battery <NUM> and discharge from the battery <NUM>.

In the flowchart shown in <FIG>, in step S11, the CPU <NUM> determines whether a DR request is received from the aggregator <NUM>. If a DR request is received, the process advances to step S12. If a DR request is not received, step S11 is repeated. In step S12, the CPU <NUM> determines whether the electric vehicle <NUM> is connected. That is, the CPU <NUM> determines whether the charge/discharge connector <NUM> of the charge/discharge control apparatus <NUM> and the charge/discharge connector <NUM> of the electric vehicle <NUM> are electrically connected via a cable. If the electric vehicle <NUM> is connected, the process advances to step S13. In the other hand, if the electric vehicle <NUM> is not connected, the process advances to step S18, and the CPU <NUM> decides not to execute charge/discharge of the battery <NUM> of the electric vehicle <NUM> by a DR plan.

In step S13, the CPU <NUM> acquires DR plan information from the aggregator <NUM>. The DR plan information can include, for example, information such as the date/time of outputting a DR request, a power [W] and capacity [Wh] of charge/discharge required for the battery <NUM> of the electric vehicle <NUM> in the DR plan, a unit price [yen/kWh] of system power, and an incentive unit price [yen/kWh] for the DR request.

In step S14, the CPU <NUM> calculates an incentive obtained by charge/discharge of the battery <NUM> by the DR plan. For example, the CPU <NUM> multiplies the capacity [Wh] required in the DR plan by the unit price [yen/kWh] based on the DR plan information, thereby calculating the incentive [yen]. Note that in this embodiment, the incentive is obtained as a cost. However, it may be obtained as a reward other than a cost.

In step S15, the CPU <NUM> calculates a power cost needed to adjust the temperature of the battery <NUM> to the target temperature by the temperature adjustment unit <NUM>. For example, the CPU <NUM> obtains information concerning the current temperature of the battery <NUM> measured by the measurement unit <NUM> of the electric vehicle <NUM>, and obtains an electric energy [kWh] (to be sometimes referred to as a "necessary electric energy" hereinafter) needed to adjust the temperature of the battery <NUM> to the target temperature by the temperature adjustment unit <NUM>. More specifically, the CPU <NUM> can obtain the relationship between the temperature change amount of the battery <NUM> and the electric energy of the temperature adjustment unit <NUM> in advance and obtain the necessary electric energy [kWh] using the relationship. Then, the CPU <NUM> multiplies the obtained necessary electric energy [kWh] by the unit price [yen/kWh] of the system power in the DR plan information, thereby calculating the power cost [yen].

In step S16, the CPU <NUM> compares the incentive calculated in step S14 with the power cost calculated in step S15. If the incentive is larger than the power cost, the process advances to step S17, and the CPU <NUM> decides to execute charge/discharge of the battery <NUM> by the DR plan. Then, the process advances to step S21 of the flowchart shown in <FIG>. On the other hand, if the incentive is equal to or smaller than the power cost, the process advances to step S18, and the CPU <NUM> decides not to execute charge/discharge of the battery <NUM> of the electric vehicle <NUM> by the DR plan.

The process advances to the flowchart shown in <FIG>. In step S21, the CPU <NUM> decides the temperature adjustment start timing of the battery <NUM> by the temperature adjustment unit <NUM>. For example, the CPU <NUM> acquires (grasps) the start timing (start time) of charge/discharge of the battery <NUM> by the DR plan based on the DR plan information. The CPU <NUM> decides the temperature adjustment start timing of the battery <NUM> based on the relationship between the temperature change amount of the battery <NUM> and the electric energy of the temperature adjustment unit <NUM>, which is acquired in advance, such that the temperature of the battery <NUM> reaches the target temperature until the start timing of charge/discharge or at the start timing of charge/discharge.

In step S22, the CPU <NUM> determines whether it is the temperature adjustment start timing decided in step S21. If it is not the temperature adjustment start timing, step S22 is repeated. On the other hand, if it is the temperature adjustment start timing, the process advances to step S23, and the CPU <NUM> starts temperature adjustment of the battery <NUM> by the temperature adjustment unit <NUM>. It is therefore possible to make the temperature of the battery <NUM> reach the target temperature until the start timing of charge/discharge of the battery <NUM> by the DR plan.

In step S24, the CPU <NUM> determines whether it is the start timing of charge/discharge of the battery <NUM> by the DR plan. If it is not the start timing of charge/discharge, step S24 is repeated. On the other hand, if it is the start timing of charge/discharge, the process advances to step S25, and the CPU <NUM> starts charge/discharge of the battery <NUM> by the DR plan. Also, in step S26, the CPU <NUM> determines whether the charge/discharge of the battery <NUM> is completed. If the charge/discharge of the battery <NUM> is not completed, step S26 is repeated to continuously perform the charge/discharge of the battery <NUM>. On the other hand, if the charge/discharge of the battery <NUM> is completed, the process advances to step S27 to stop the charge/discharge of the battery <NUM>.

As described above, the charge/discharge control apparatus <NUM> (CPU <NUM>) according to this embodiment calculates the incentive obtained by charge/discharge of the battery <NUM> by the DR plan and the power cost needed to adjust the temperature of the battery to the target temperature by the temperature adjustment unit <NUM>, and determines, based on the calculation result, whether to perform charge/discharge of the battery <NUM>. This can reduce a loss for a customer caused by adjusting the temperature of the battery <NUM> and appropriately ensure interests (incentive) obtained by the charge/discharge of the battery <NUM> by the DR plan.

In addition, the charge/discharge control apparatus <NUM> (CPU <NUM>) according to this embodiment controls temperature adjustment of the battery <NUM> by the temperature adjustment unit <NUM> such that the temperature of the battery <NUM> reaches the target temperature until the start timing of charge/discharge of the battery <NUM> by the DR plan. Since this can set the charge/discharge characteristic of the battery <NUM> to a predetermined value or more until the start timing of charge/discharge, charge/discharge of the battery <NUM> according to the DR plan can efficiently be executed.

Here, in this embodiment, each step of the flowcharts shown in <FIG> and <FIG> is executed by the CPU <NUM> of the charge/discharge control apparatus <NUM>. However, the present invention is not limited to this, and the steps may be executed by the processor (ECU <NUM>) of the electric vehicle <NUM> (power unit), or may be executed by the CPU <NUM> of the aggregator <NUM> (management server). That is, the function of the charge/discharge control apparatus <NUM> (CPU <NUM>) according to this embodiment may be held by at least one of the processor (ECU <NUM>) of the electric vehicle (power unit) and the CPU <NUM> of the aggregator <NUM> (management server). When the CPU <NUM> of the aggregator <NUM> (management server) is caused to execute each step of the flowcharts shown in <FIG> and <FIG>, centralized control of a plurality of power units (an electric vehicle and a stationary battery) by the management server can be performed. If a plurality of power units are controlled, and both the electric vehicle and the stationary battery exist as the power units, centralized control by the management server is effective.

Also, in this embodiment, an example in which charge/discharge of the battery of the electric vehicle is controlled as a power unit has been described. The present invention can also be applied to a case in which charge/discharge of a stationary battery is controlled as a power unit. That is, in the example shown in <FIG>, at least one of the electric vehicles (EVs) <NUM> may be replaced with a stationary battery. In this case, each step of the flowcharts shown in <FIG> and <FIG> may be executed by the CPU <NUM> of the charge/discharge control apparatus <NUM>, a processor (ECU) incorporated in the stationary battery, or the CPU <NUM> of the aggregator <NUM> (management server).

Claim 1:
A control apparatus (<NUM>) configured to control a power unit (<NUM>),
the power unit including a battery (<NUM>), and a temperature adjuster (<NUM>) configured to adjust a temperature of the battery to a target temperature at the time of charge or discharge of the battery,
characterized in that the control apparatus is configured to:
obtain, from a server, information indicating a start timing of the charge or discharge of the battery requested in a demand response plan used to adjust a power demand and supply in a power market, and
control the temperature adjuster based on the information, such that the temperature of the battery reaches the target temperature at the start timing.