CHARGING CONTROL DEVICE, ELECTRIC VEHICLE CHARGING
SYSTEM, AND ELECTRIC VEHICLE CHARGING METHOD
Technical Field
[0001]
The present invention relates to a charging control device, an electric
vehicle charging system, and an electric vehicle charging method.
Background Art
[0002]
It is preferable that a secondary battery (battery) of an electric vehicle be
charged in a time period in which the charging time and electricity fee are the
most appropriate. The time period in which the electricity fee is the most
appropriate is a time period in which the electricity fee is low compared to other
time periods, for example, a time period during which nighttime power, which
has a low demand, is supplied. Charging the electric vehicle in such a time
period allows the user who performs the charging to reduce the electricity fee,
and also causes the business operator that supplies the electricity to have an
increase in power demand in a time period that has a low demand.
[0003]
For the purpose of reducing energy costs for the user, Patent Document 1
describes a device that derives an energy demand profile from vehicle internal
operation data to create a future demand plan, uses the demand plan to derive a
stopping time and stopping frequency of a vehicle, compares the stopping time
of the vehicle with an indication of an energy price transition, and on the basis
of the result of the comparison, creates an optimal charging plan with regard to
time and price for charging the vehicle.
Citation List
Patent Literature
[0004]
Patent Literature 1: Japanese Unexamined Patent Application Publication
(translation of PCT application) No. 2011-527566A
Summary of Invention
Technical Problem
[0005]
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However, a conventional electric vehicle is connected to a charging
device, and the secondary battery is charged up to a fully charged state.
Therefore, in a state where the charging rate of the secondary battery of the
electric vehicle is high, even if an optimal charging plan such as that described
in Patent Document 1 is created and the secondary battery is charged, for the
user who performs the charging, the electricity fee reduction effect does not
increase, and for the power company that supplies the power, there is no
increase in the power demand in a time period that has a low demand.
[0006]
The present invention has been devised taking such circumstances into
consideration, and an object thereof is to provide a charging control device, an
electric vehicle charging system, and an electric vehicle charging method,
which make it possible to ensure an available capacity of a secondary battery of
an electric vehicle at a timing appropriate for charging the secondary battery.
Solution to Problem
[0007]
In order to solve the aforementioned problem, the charging control
device, the electric vehicle charging system, and the electric vehicle charging
method of the present invention employ the following means.
[0008]
Specifically, a charging control device according to a first aspect of the
present invention is a charging control device that controls a charging device
for charging a secondary battery of an electric vehicle. The charging control
device controls the charging device so as to charge the secondary battery. The
secondary battery is charged such that the amount of remaining charged power
of the secondary battery is equal to or greater than the amount of estimated
necessary power and is less than the amount of charged power that prevents a
power deficiency in an interval from the start of charging the secondary battery
to a prescribed time.
[0009]
According to this configuration, the charging device is controlled so as
to charge the secondary battery, the secondary battery is charged such that the
amount of remaining charged power of the secondary battery of the electric
vehicle is equal to or greater than the amount of estimated necessary power and
is less than the amount of charged power that prevents a power deficiency in an
interval from the start of charging the secondary battery to the prescribed time.
This prevents the secondary battery of the electric vehicle from being fully
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charged, which brings the secondary battery 20 into a charged state in which
available capacity for additional charging remains. It should be noted that the
prescribed time, for example, is a time at which a time period during which the
electricity fee is low compared to other time periods starts, namely, a time at
which nighttime power can be used.
[0010]
Consequently, this configuration makes it possible to ensure an available
capacity of the secondary battery of the electric vehicle at a timing appropriate
for charging the secondary battery.
[0011]
In the aforementioned first aspect, it is preferable that the charging
control device be provided with: estimation value calculation means for
calculating an estimation value for an amount of power necessary from the start
of charging the secondary battery to the prescribed time on the basis of power
consumption information indicating changes over time in a past amount of
power consumed by the electric vehicle; and control means for controlling the
charging device so as to charge the secondary battery, the secondary battery
being charged such that the estimation value calculated by the estimation value
calculation means is satisfied.
[0012]
According to this configuration, on the basis of the power consumption
information indicating changes over time in the past amount of power consumed
by the electric vehicle, an estimation value for the amount of power necessary
from when the start of charging the secondary battery of the electric vehicle to
the prescribed time is calculated by the estimation value calculation means.
The calculated estimation value is, in other words, the amount of power
that should be charged to the secondary battery in order to prevent a power
deficiency if the electric vehicle is made to travel until the prescribed time.
[0013]
Then, the control means cause the secondary battery of the electric
vehicle to be charged such that the calculated estimation value is satisfied.
Thus, charging the secondary battery of the electric vehicle is stopped at the
amount of charged power that prevents a power deficiency in an interval up to
the next prescribed time even if the electric vehicle is made to travel, which
results in the secondary battery having available capacity for additional
charging.
[0014]
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Consequently, this configuration makes it possible to reliably ensure an
available capacity of the secondary battery of the electric vehicle at a timing
appropriate for charging the secondary battery, without the electric vehicle
having a power deficiency.
[0015]
In the aforementioned first aspect, it is preferable that the control means
control the charging device so as to charge the secondary battery in a prescribed
time period.
[0016]
According to this configuration, the charging based on the estimation
value does not cause the secondary battery to be fully charged, and therefore,
charging the secondary battery in the prescribed time period such as a time
period during which the electricity fee is low compared to other time periods
makes it possible for power in any time period to be effectively used.
[0017]
In the aforementioned first aspect, it is preferable that the control means,
when surplus power is generated in a power system that supplies power to the
charging device, control the charging device so as to charge the secondary
battery.
[0018]
Power generated by natural energy such as sunlight and wind power may
increase excessively due to the instability of natural energy. In such a case, if
the excessively increased surplus power is not consumed, the amount of
generated power is reduced or the surplus power is wastefully consumed.
According to this configuration, the secondary battery is not fully
charged by the charging based on the estimation value, which makes it possible
to additionally charge the secondary battery when surplus power is generated in
the power system. Thus, the surplus power is consumed by the charging to the
secondary battery, and therefore, this configuration allows the surplus power
generated in the power system to be used without being wasted.
[0019]
In the aforementioned first aspect, it is preferable that the estimation
value calculation means calculate, on the basis of the power consumption
information, an average value of the past amount of consumed power in a time
interval from the start of charging the secondary battery to the prescribed time,
and a variance value of the past amount of consumed power in the time interval,
and calculate the estimation value on the basis of the average value and the
variance value.
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[0020]
According to this configuration, the estimation value for the amount of
power necessary for the electric vehicle up to the prescribed time can be
calculated with greater accuracy.
[0021]
An electric vehicle charging system according to a second aspect of the
present invention is provided with a charging device that charges a secondary
battery of an electric vehicle, and the charging control device described
hereinabove.
[0022]
An electric vehicle charging method according to a third aspect of the
present invention is an electric vehicle charging method for controlling a
charging device that charges a secondary battery of an electric vehicle. In
such a method, the charging device is controlled so as to charge the secondary
battery, and the secondary battery is charged such that the amount of remaining
charged power of the secondary battery is equal to or greater than the amount of
estimated necessary power and is less than the amount of charged power that
prevents a power deficiency in an interval from a start of charging the
secondary battery to a prescribed time.
Advantageous Effects of Invention
[0023]
According to the present invention, an excellent effect is demonstrated in
that it is possible to ensure an available capacity of a secondary battery of an
electric vehicle at a timing appropriate for charging the secondary battery.
Brief Description of Drawings
[0024]
FIG. 1 is a configuration diagram of an electric vehicle charging system
according to a first embodiment of the present invention.
FIG. 2 is a functional block diagram depicting functions of a charging
device and a management center in the electric vehicle charging system
according to the first embodiment of the present invention.
FIG. 3 is a flowchart depicting the flow of electric vehicle charging
processing according to the first embodiment of the present invention.
FIG. 4 is a graph showing an example of the relationship between the
travel distance of an electric vehicle and time according to the first embodiment
of the present invention.
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FIG. 5 is a graph showing a power consumption pattern according to the
first embodiment of the present invention.
FIG. 6 is a graph showing a power consumption density distribution
according to the first embodiment of the present invention.
FIG. 7 is a graph showing simulation results for the amount of remaining
charged power of a secondary battery that has been charged so as to satisfy the
amount of estimated necessary power according to the first embodiment of the
present invention.
FIG. 8 is a graph showing the charge status of the secondary battery
every hour according to the first embodiment of the present invention.
FIG. 9 is a configuration diagram of an electric vehicle charging system
according to a second embodiment of the present invention.
FIG. 10 is a functional block diagram depicting functions of a charging
device and a management center in the electric vehicle charging system
according to the second embodiment of the present invention.
Description of Embodiments
[0025]
Hereinafter, an embodiment of a charging control device, an electric
vehicle charging system, and an electric vehicle charging method according to
the present invention will be described with reference to the drawings.
[0026]
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be
described.
[0027]
FIG. 1 is a schematic diagram of an electric vehicle charging system 10
according to the first embodiment.
The electric vehicle charging system 10 includes a charging device 12, a
commercial power system 14 (power transmission network), and a management
center 16. In such an electric vehicle charging system 10, a secondary battery
20 (see FIG. 2) of an electric vehicle 18 is charged by the charging device 12.
It should be noted that the electric vehicle 18 is not limited to an electric
vehicle that is driven only by power charged in the secondary battery 20, and
may be a vehicle (plug-in hybrid vehicle) that is a hybrid vehicle and that
allows the secondary battery 20 to be charged from outside.
[0028]
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The charging device 12 transmits power, which is supplied from the
commercial power system 14, for charging the secondary battery 20 to the
electric vehicle 18.
The charging device 12 includes, for example: a charging device 12-A
that is installed along a road on which the electric vehicle 18 travels and that
transmits power to the electric vehicle 18 during travel; a charging device 12-B
that is installed adjacent to a commercial car park for temporary use, monthly
use, or the like, or a car park of a commercial facility and that transmits power
to the parked electric vehicle 18; and a charging device 12-C that is installed
adjacent to a car park of a general house and that transmits power to the parked
electric vehicle 18.
It should be noted that the charging device 12 according to the first
embodiment is assumed to transmit power to the electric vehicle 18 by wireless
power transmission such as electromagnetic waves (for example, microwaves);
however, the present invention is not limited thereto, and the charging device 12
may transmit power to the electric vehicle 18 by wired power transmission.
[0029]
Furthermore, the charging device 12 transmits, to the management center
16, vehicle information that will be described in detail below, and charged
power amount information indicating the amount of power charged to the
electric vehicle 18. The vehicle information is information transmitted from
the electric vehicle 18 to the charging device 12.
[0030]
The management center 16 controls the charging device 12 such that
power is transmitted to the electric vehicle 18, on the basis of the vehicle
information transmitted from the charging device 12.
Furthermore, in the electric vehicle charging system 10 according to the
first embodiment, between the management center 16 and an electricity
business operator 22, the billing and payment of electricity fee are carried out
on the basis of power consumption amount information regarding the amount of
power consumed by each charging device 12, and between the management
center 16 and the owner of the electric vehicle 18 (including a contractor, an
individual, and a corporation permitted to use the charging device 12), the
billing and payment of charging service fee are carried out on the basis of
charged power amount information transmitted to the management center 16.
[0031]
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FIG. 2 is a functional block diagram depicting functions according to the
functions of the charging device 12 and the management center 16 in the
electric vehicle charging system 10.
[0032]
The electric vehicle 18 is provided with a power consumption amount
storage unit 30, a transmission unit 32, and a power reception unit 34 together
with the secondary battery 20.
[0033]
The power consumption amount storage unit 30 sequentially stores
changes over time in the amount of power consumed by the electric vehicle 18.
It should be noted that the changes over time in the amount of consumed power
are stored in the power consumption amount storage unit 30 every minute, for
example.
[0034]
The transmission unit 32 transmits, to the charging device 12,
identification (ID) information specific to the electric vehicle 18, and vehicle
information including power consumption information indicating changes over
time in the past amount of consumed power stored in the power consumption
amount storage unit 30.
It should be noted that the ID information, which specifies the electric
vehicle 18, is associated with information indicating the owner of the electric
vehicle 18 (for example, the address, name, and the like of the owner).
[0035]
The power consumption amount information transmitted to the charging
device 12 represents changes over time in the amount of power consumed in an
interval from the timing of the last transmission to the timing of new
transmission.
The power consumption amount storage unit 30 may delete the
transmitted changes over time in the amount of consumed power, each time the
vehicle information is transmitted from the transmission unit 32 to the charging
device 12. Furthermore, a transmitted amount of consumed power stored in
the power consumption amount storage unit 30 may be deleted once it has been
confirmed that the charging device 12 has received the power consumption
amount information.
[0036]
In this way, deleting the amount of consumed power stored in the electric
vehicle 18 each time the power consumption amount information is transmitted
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to the charging device 12 allows the storage capacity of the power consumption
amount storage unit 30 to be small.
[0037]
In addition, instead of the aforementioned power consumption amount
information, difference information indicating a difference from the power
consumption amount transmitted the last time may be transmitted to the
management center 16. This difference information may be calculated by the
electric vehicle 18, or by the charging device 12.
[0038]
The power reception unit 34 receives power transmitted from the
charging device 12, and charges the secondary battery 20. It should be noted
that the electric vehicle 18 that receives power by wireless power transmission
has the power reception unit 34 provided on the roof.
[0039]
The charging device 12 is provided with a reception unit 36 and a power
transmission unit 38.
[0040]
The reception unit 36 receives vehicle information from the electric
vehicle 18, and outputs the vehicle information to a charging control device 40
provided in the management center 16.
[0041]
The power transmission unit 38 transmits power to the power reception
unit 34 on the basis of a charging instruction indicating the amount of power to
be transmitted to the electric vehicle 18 that is input from the charging control
device 40.
Furthermore, the power transmission unit 38, after the power
transmission to the electric vehicle 18, outputs charged power amount
information to the charging control device 40.
[0042]
The management center 16 is provided with the charging control device
40.
[0043]
The charging control device 40 controls the charging device 12 so as to
charge the secondary battery 20. The secondary battery 20 is charged such
that the amount of remaining charged power of the secondary battery 20 of the
electric vehicle 18 is equal to or greater than the amount of estimated necessary
power and is less than the amount of charged power that prevents a power
deficiency in an interval from the start of charging the secondary battery 20 to a
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prescribed time. This control prevents the secondary battery 20 of the electric
vehicle 18 from being fully charged, which brings the secondary battery 20 into
a charged state in which available capacity for additional charging remains.
[0044]
It should be noted that the prescribed time, for example, is a time at
which a time period during which the electricity fee is low compared to other
time periods starts, namely, a time at which nighttime power supply is started,
and is a time at which power the secondary battery 20 of the electric vehicle 18
is charged on a scheduled basis (hereinafter referred to as a "start time of
scheduled charging").
[0045]
The charging control device 40 according to the first embodiment is
provided with a vehicle information storage unit 42, an estimation value
calculation unit 44, a charging device control unit 46, and a billing unit 48.
[0046]
The vehicle information storage unit 42 stores vehicle information
output from the charging device 12, for each electric vehicle 18, on the basis of
the ID information included in the vehicle information.
Thus, each time the vehicle information is input, new power
consumption information is added to the power consumption information of
each electric vehicle 18 stored in the vehicle information storage unit 42.
[0047]
The estimation value calculation unit 44 calculates, on the basis of the
power consumption information stored in the vehicle information storage unit
42, an estimation value for the amount of power necessary from the start of
charging the secondary battery 20 to the start time of scheduled charging, for
each electric vehicle 18, as the amount of estimated necessary power.
The amount of estimated necessary power is, in other words, the amount
of power to be charged to the secondary battery 20 in order to prevent a power
deficiency even if the electric vehicle 18 is made to travel until the start time of
scheduled charging.
It should be noted that the amount of estimated necessary power may be
a value obtained by adding a tolerance (for example, 10% of the calculated
estimation value), which more reliably prevents the electric vehicle 18 from
resulting in a power deficiency, to the estimation value calculated by the
estimation value calculation unit 44.
[0048]
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The charging device control unit 46 controls the charging device 12 so as
to charge the secondary battery 20 of the electric vehicle 18 such that the
amount of estimated necessary power calculated by the estimation value
calculation unit 44 is satisfied.
Specifically, the charging device control unit 46 calculates a charging
instruction indicating a charging time and charging power for the electric
vehicle 18 that satisfy the amount of estimated necessary power, and outputs the
charging instruction to the power transmission unit 38 of the charging device
12
[0049]
Furthermore, the charging device control unit 46 controls the charging
device 12 so as to charge the secondary battery 20 of the electric vehicle 18 in a
prescribed time period. The prescribed time period, for example, is a time
period during which nighttime power is used to charge the secondary battery 20
on a scheduled basis, and is hereinafter referred to as a "time period of
scheduled charging".
[0050]
On the other hand, the billing unit 48 calculates a charging service fee
for the owner of each electric vehicle 18 on the basis of the charged power
amount information of each electric vehicle 18 output from the charging device
12. It should be noted that the charging service fee is, for example,
determined by a variety of methods in which the charging service fee is
calculated by multiplying the amount of charged power of each electric vehicle
18 by a prescribed value every month, or is a fixed amount unrelated to the
amount of charged power.
The management center 16 bills the charging service fee with respect to
the owner of the electric vehicle 18, such as by debiting the charging service fee
each month from a preregistered bank account, or by issuing an invoice.
[0051]
It should be noted that the charging control device 40, for example,
includes a central processing unit (CPU), a random access memory (RAM), and
a computer-readable recording medium. Also, a sequence of processing for
realizing the various functions of the estimation value calculation unit 44 and
the charging device control unit 46 is recorded on a recording medium or the
like in the form of a program, and the various functions are realized by the CPU
reading out this program to the RAM or the like and executing information
processing/calculation processing.
[0052]
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Hereinafter, the action of the charging control device 40 according to the
first embodiment will be described.
[0053]
FIG. 3 is a flowchart depicting the flow of processing (electric vehicle
charging processing) performed by the charging control device 40 in the case
where the electric vehicle 18 is positioned in a prescribed charging location and
charging of the secondary battery 20 is started. It should be noted that the
prescribed charging location is, for example, an area in which the charging
device 12-A adjacent to the road can charge the electric vehicle 18 during travel,
or a parking location to which the charging devices 12-B and 12-C are adjacent.
[0054]
First, in step 100, it is determined whether or not the vehicle information
from the electric vehicle 18 has been input via the charging device 12. If the
result of the decision in step 100 is YES, the control proceeds to step 102. If
the result is NO, the control waits until the vehicle information is input. When
new vehicle information is input, new power consumption information included
in the vehicle information is added to the power consumption information of
each electric vehicle 18 stored in the vehicle information storage unit 42.
[0055]
In the next step 102, it is determined whether or not the present time is
within the time period of scheduled charging. If the result of the decision in
step 102 is YES, the control proceeds to step 114. If the result is NO, the
control proceeds to step 104.
[0056]
In step 104, the estimation value calculation unit 44 calculates the
amount of estimated necessary power.
[0057]
Hereinafter, the details of the calculation of the amount of estimated
necessary power will be described.
[0058]
First, the estimation value calculation unit 44 reads out, from the vehicle
information storage unit 42, power consumption information corresponding to
the ID information included in the input vehicle information.
The estimation value calculation unit 44 calculates, on the basis of the
read-out power consumption information, an average value of the past amount
of consumed power (for example, for several years) in a time interval from the
start of charging the secondary battery 20 to the start time of scheduled
charging, and a variance value of the past amount of consumed power in the
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time interval. Then, the estimation value calculation unit 44 calculates the
amount of estimated necessary power on the basis of the calculated average
value and variance value.
It should be noted that the start time of the charging of the secondary
battery 20 is a time at which the electric vehicle 18 is positioned in the charging
location in order to be charged, in other words, a time at which the vehicle
information is transmitted from the electric vehicle 18 to the charging device 12.
In the description hereinafter, the "start time of the charging of the secondary
battery 20" is also referred to as "present".
[0059]
Furthermore, in the first embodiment, a standard deviation is used as the
variance value. In addition, in the first embodiment, 3G is used as the standard
deviation; however, the present invention is not restricted thereto, and 0, 26, 4o,
or the like may be used as the standard deviation. It should be noted that, by
using 36 as the standard deviation, the amount of estimated necessary power is
calculated with consideration also being given to the case where the amount of
power consumed by the electric vehicle 18 suddenly becomes excessive.
[0060]
The following Expression 1 is an example of an arithmetic expression
that uses Bayes' theorem to calculate the amount of estimated necessary power.
In Expression 1, the amount of estimated necessary power P is calculated by
adding a best estimation value for a time history density of the amount of power
consumed in an interval from the present time t 1 to a start time of scheduled
charging t2, and a standard deviation for the time history density of the amount
of power consumed for a time, a day of the week, a day of the month, and a
month thereof.
It should be noted that the best estimation value is a conditional
probability distribution, and more specifically, is the average value of the
interval from the present time tl to the start time of scheduled charging t2 for a
day of the week, a day of the month, and a month thereof.
[Expression 1]
2
P = (PD + .VAPDt2inie + APD 2day of the week APD day of the month+ APDmonth
PD: Best estimation value for time history density of amount of consumed power (average value)
A PD.{.: Standard deviation for time history density of amount of consumed power (305 value)
(X: time, day of the week, day of the month, month)
tl: present time
t2: start time of scheduled charging
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[0061]
Here, FIG. 4 is a graph showing an example of the relationship between
the travel distance of the electric vehicle 18 and time. As shown in FIG. 4, on
weekdays on which the electric vehicle 18 is used for commuting, the travel
distance increases in the early morning and the evening; however, on a weekend,
there is a lot of variation in the time at which the travel distance increases, and
the travel distance also increases compared to the weekdays. In this way, on
weekdays and on a weekend, the relationship between the travel distance of the
electric vehicle 18 and time is different.
Furthermore, in the electric vehicle 18, the charged power of the
secondary battery 20 is also used for an air-conditioning device that is provided
in the electric vehicle 18. Therefore, despite the travel distance being the
same, the amount of power consumed by the electric vehicle 18 increases in the
summer and winter compared to the spring and fall, and despite the time and
day of the week being the same, the amount of power consumed thereof is
different depending on the month.
[0062]
Therefore, as indicated in Expression (1), the estimation value
calculation unit 44 calculates the standard deviation in accordance with a time,
a day of the week, a day of the month, and a month, and adds the standard
deviation to the average value, thereby taking fluctuations of a time, a day of
the week, a day of the month, and a month into consideration for the amount of
estimated necessary power P. Thus, the estimation value calculation unit 44
can calculate the amount of estimated necessary power P with greater accuracy.
[0063]
FIG. 5 is a graph showing an example of the relationship (power
consumption pattern) between the power consumption of the electric vehicle 18
and time. Whereas power consumption increases over time as the electric
vehicle 18 consumes power, power consumption is constant when power is not
consumed.
The vehicle information storage unit 42 stores the relationship between
power consumption and time such as that shown in FIG. 5 every Sunday, every
day, and every month, for each electric vehicle 18 as power consumption
information.
[0064]
FIG. 6 is a graph showing the relationship (power consumption density
distribution) between power consumption density and time. The power
consumption density increases over time as the electric vehicle 18 gradually
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accelerates and consumes power. When the speed becomes constant, the
power consumption density also becomes constant, and the power consumption
density decreases over time during deceleration. Then, when the electric
vehicle 18 stops, in other words, when the electric vehicle 18 is not consuming
power, the power consumption density becomes 0 (zero).
It should be noted that the power consumption density of a prescribed
time interval (for example, from the present time tl to the start time of
scheduled charging t2) is referred to as a time history density.
[0065]
Then, the estimation value calculation unit 44 according to the first
embodiment calculates the average value and standard deviation for the amount
of consumed power, on the basis of the time history density of the amount of
consumed power.
Thus, the amount of estimated necessary power P which can more
reliably prevent a power deficiency of the electric vehicle 18 up to the start time
of scheduled charging t2 is calculated.
[0066]
In the next step 106, it is determined whether or not the amount of
estimated necessary power P indicated in the following Expression 2 is equal to
or less than a present amount of remaining charged power Pnow of the secondary
battery 20. The result of the decision in step 106 is YES, charging is not
necessary, and the control proceeds to step 112. If the result is NO, charging
is necessary, and the control proceeds to to step 108.
[Expression 2]
P < P,1 0 1V (Charging not necessary)
P > Pnow (Charging necessary)
[0067]
In step 108, the charging device control unit 46 calculates a charging
instruction on the basis of a difference between the estimated necessary power
and the amount of remaining charged power such that the amount of remaining
charged power of the secondary battery 20 satisfies the amount of estimated
necessary power.
[0068]
In step 110, the charging device control unit 46 outputs the calculated
charging instruction to the charging device 12, and the control proceeds to step
112.
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When the charging instruction is input, the charging device 12 transmits
the electromagnetic waves indicated by the charging instruction from the power
transmission unit 38. When the electromagnetic waves are transmitted from
the power transmission unit 38 of the charging device 12, the electric vehicle 18
charges the secondary battery 20 with the power received by the power
reception unit 34.
[0069]
As a result of the processing of step 110, charging is stopped at the
estimated necessary power which prevents a power deficiency up to the
subsequent start time of scheduled charging even if the electric vehicle 18 is
made to travel, resulting in the secondary battery 20 of the electric vehicle 18
being not fully charged and having available capacity for additional charging.
[0070]
In step 112, it is determined whether or not the present time is the start
time of scheduled charging. The result of the decision in step 112 is YES, the
control proceeds to step 114. If the result is NO, the control waits until the
start time of scheduled charging.
[0071]
In step 114, the charging device control unit 46 calculates a charging
instruction to fully charge the secondary battery 20.
[0072]
In step 116, the charging device control unit 46 outputs the calculated
charging instruction to the charging device 12.
When the charging instruction is input, the charging device 12 transmits
the electromagnetic waves indicated by the charging instruction from the power
transmission unit 38. When the electromagnetic waves are transmitted from
the power transmission unit 38 of the charging device 12, the electric vehicle 18
charges the secondary battery 20 with the power received by the power
reception unit 34.
[0073]
As a result of the processing of step 116, the secondary battery 20 of the
electric vehicle 18 is fully charged in a time period of scheduled charging
[0074]
When step 116 ends, the electric vehicle charging processing ends.
[0075]
FIG. 7 is a graph showing simulation results for the amount of remaining
charged power of the secondary battery 20 when the present time has become
the start time of scheduled charging.
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In this simulation, when the travel distance becomes an average of 30
km/day, there is variation of ±15 km/day on weekdays, there is variation of ±30
km/day on weekends, the electricity cost is 10 km/kWh, and a performance
decline when the air-conditioner is used is anticipated according to the season.
Also, the charged power capacity of the secondary battery 20 is assumed to be
16 kWh.
[0076]
In the results showing in FIG. 7, the amount of remaining charged power
of the secondary battery 20 has an average of 11.5 kWh and a standard
deviation of 2.3 kWh, and the probability that the amount of remaining charged
power is 0 (zero) prior to the start time of scheduled charging, in other words,
the probability of a power deficiency is 1.1 x 10-6. This probability, which is
the probability that a power deficiency will occur 0.004 times in 10 years of
travel, is a value with which there is absolutely no problem for use of the
electric vehicle 18.
[0077]
FIG. 8 is a graph showing the charge status of secondary battery 20 every
hour.
FIG. 8 shows the charge status corresponding to the simulation results of
FIG. 7, in which the proportion of the charging that uses nighttime power of
from 23:00 to 07:00 is extremely high. Specifically, the amount of power
charged during the daytime is 0.1 kWh, whereas the amount of power charged
using nighttime power is 4.0 kWh.
[0078]
In this way, in the electric vehicle charging system 10 according to the
first embodiment, the secondary battery 20 is not fully charged by the charging
based on the amount of estimated necessary power, and a full charge can be
performed by charging the secondary battery 20 in the time period of scheduled
charging, and therefore it becomes possible for power in any time period to be
effectively used.
[0079]
As described above, the charging control device 40 according to the first
embodiment controls the charging device 12 so as to charge the secondary
battery 20, and the secondary battery 20 is charged such that the amount of
remaining charged power of the secondary battery 20 of the electric vehicle 18
is less than the amount of charged power that prevents a power deficiency in an
interval from the start of charging the secondary battery 20 to the start time of
scheduled charging.
WO 2015/029119 Al 18 PCT/W2013/072764
Consequently, with the charging control device 40 according to the first
embodiment, it is possible to ensure an available capacity of the secondary
battery 20 of the electric vehicle 18 at a timing appropriate for charging the
secondary battery 20.
[0080]
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be
described.
[0081]
FIG. 9 is a configuration diagram of an electric vehicle charging system
10 according to the second embodiment. It should be noted that components
in FIG. 9 that are the same as those in FIG. 1 are denoted by the same reference
signs as in FIG. 1, and descriptions thereof are omitted.
[0082]
The power system 14 according to the second embodiment has a solar
battery 50 or a wind power generation device 52 connected thereto in order for
power to be generated by natural energy such as sunlight or wind power.
[0083]
Furthermore, a power measurement device 54 that measures the power of
the power system 14 is provided in a power transmission network.
The power measurement device 54, in the case where a measurement
result is greater than a standard power, outputs surplus power information
indicating that surplus power has been generated in the power system 14, to the
management center 16.
[0084]
FIG. 10 is a functional block diagram depicting functions of the charging
device 12 and the management center 16 in the electric vehicle charging system
10 according to the second embodiment. It should be noted that components
in FIG. 10 that are the same as those in FIG. 2 are denoted by the same reference
signs as in FIG. 1, and descriptions thereof are omitted.
[0085]
The management center 16 according to the second embodiment is
provided with a surplus power determination unit 60.
The surplus power determination unit 60 determines whether or not
surplus power has been generated due to the amount of generated power
exceeding the power demand. Specifically, the surplus power determination
unit 60 determines that surplus power has been generated if receiving surplus
power information from the power measurement device 54.
WO 2015/029119 Al 19 PCT/JP2013/072764
[0086]
Here, there are cases where power generated by natural energy such as
sunlight and wind power increases excessively due to the instability of natural
energy. In such cases, if the excessively increased surplus power is not
consumed, the amount of power generated by the solar battery 50 or the wind
power generation device 52 is reduced, or the surplus power is wastefully
consumed.
[0087]
The charging control device 40 according to the second embodiment, in
the case where the surplus power determination unit 60 determines that surplus
power has been generated in the power system 14, controls the charging device
12 so as to charge the secondary battery 20 of the electric vehicle 18.
The secondary battery 20 is not fully charged by the charging based on
the estimated necessary power value, and therefore, in the case where surplus
power has been generated in the power system 14, it is possible for the
secondary battery 20 to be additionally charged. Thus, surplus power is
consumed by the charging to the secondary battery 20, and therefore, in the
electric vehicle charging system 10 according to the second embodiment, the
surplus power generated in the power system 14 can be used without being
wasted.
[0088]
Hereinabove, the present invention has been described using the
aforementioned embodiments; however, the technical scope of the present
invention is not limited to the scope described in the aforementioned
embodiments. Various modifications or improvements can be added to the
aforementioned embodiments without deviating from the gist of the invention,
and aspects obtained by adding the modifications or improvements are also
included within the technical scope of the present invention.
[0089]
For example, in the aforementioned embodiments, the aspect in which
the electric vehicle 18 is charged by wireless power transmission has been
described; however, the aspect may be implemented in a manner such that the
electric vehicle 18 is charged by wired power transmission in which a plug
provided in the charging device 12 is inserted into the electric vehicle 18. In
this aspect, the plug remains inserted into the electric vehicle 18 positioned in
the charging location.
[0090]
WO 2015/029119 Al 20 PCT/JP2013/072764
Furthermore, the flow of the electric vehicle charging processing
described in the aforementioned embodiments is also an example, and
unnecessary steps may be deleted, new steps may be added, and the processing
order may be changed without deviating from the gist of the present invention.
Reference Signs List
[0091]
10 Electric vehicle charging system
12 Charging device
14 Power system
18 Electric vehicle
20 Secondary battery
40 Charging control device
44 Estimation value calculation unit
46 Charging device control unit

Claims
[Claim 1]
A charging control device that controls a charging device, the charging
device charging a secondary battery of an electric vehicle, wherein
the charging control device controls the charging device so as to charge
the secondary battery, the secondary battery being charged such that an amount of
remaining charged power of the secondary battery is equal to or greater than an
amount of estimated necessary power and is less than an amount of charged
power that prevents a power deficiency in an interval from a start of charging the
secondary battery to a prescribed time.
[Claim 2]
The charging control device according to claim 1, further comprising:
estimation value calculation means for calculating an estimation value for
an amount of power necessary from the start of charging the secondary battery to
the prescribed time based on power consumption information indicating changes
over time in a past amount of consumed power by the electric vehicle; and
control means for controlling the charging device so as to charge the
secondary battery, the secondary battery being charged such that the estimation
value calculated by the estimation value calculation means is satisfied.
[Claim 3]
The charging control device according to claim 2, wherein
the control means control the charging device so as to charge the
secondary battery in a prescribed time period.
[Claim 4]
The charging control device according to claim 2 or 3, wherein
the control means, when surplus power is generated in a power system that
supplies power to the charging device, control the charging device so as to charge
the secondary battery.
[Claim 5]
The charging control device according to any one of claims 2 to 4, wherein
the estimation value calculation means calculate, based on the power
consumption information, an average value of the past amount of consumed
power in a time interval from the start of charging the secondary battery to the
prescribed time, and a variance value of the past amount of consumed power in
WO 2015/029119 Al 2 PCT/JP2013/072764
the time interval, and calculates the estimation value based on the average value
and the variance value.
[Claim 6]
An electric vehicle charging system comprising:
a charging device that charges a secondary battery of an electric vehicle;
and
the charging control device described in any one of claims 1 to 5.
[Claim 7]
An electric vehicle charging method for controlling a charging device, the
charging device charging a secondary battery of an electric vehicle, comprising
the step of:
controlling the charging device so as to charge the secondary battery, the
secondary battery being charged such that an amount of remaining charged power
of the secondary battery is equal to or greater than an amount of estimated
necessary power and is less than an amount of charged power that prevents a
power deficiency in an interval from a start of charging the secondary battery to
a prescribed time.