JP7703879B2 - Charging control method and charging control device - Google Patents

Description

The present invention relates to a charging control method and a charging control device for vehicles that require charging of the drive battery, such as electric vehicles and hybrid vehicles.

A vehicle information providing device is known that, when the remaining charge of an electric vehicle is below a predetermined threshold, calculates the range in which the vehicle can travel based on the current remaining charge and displays the locations of charging spots that are within that range (see Patent Document 1).

JP 2019-95310 A

However, with the above-mentioned conventional vehicle information device, even if the remaining charge level is below a certain threshold, there is a problem in that the waiting time for charging can be long depending on the congestion of the charging spot, such as during busy hours or in a location with high access.

The problem that the present invention aims to solve is to provide a charging control method and a charging control device that can prevent the charging wait time from becoming long when the remaining charge of the driving battery is below a predetermined threshold.

The present invention solves the above problem by setting a first charging threshold at which the driving battery needs to be charged and a second charging threshold at which the remaining charge is greater than the first charging threshold, detecting the remaining charge and comparing it with the first and second charging thresholds, and outputting a charging instruction to charge if the remaining charge is less than the second charging threshold but greater than the first charging threshold and there is a charging spot where the predicted charging wait time is less than a predetermined value.

According to the present invention, when the remaining charge of the driving battery is below a predetermined threshold, it is possible to prevent the charging wait time from becoming long.

1 is a block diagram showing an embodiment of a charge control system including a charge control device according to the present invention; 4 is a graph showing an example of the fluctuation with respect to elapsed time of the SOC (remaining charge) and the charge waiting time of a battery of a vehicle in which charging control is executed by the charge control device of the present invention. 2A and 2B are diagrams for explaining an example of a process executed by the charging planning unit in FIG. 1 . FIG. 1 is a diagram for explaining an example of a scene in which a charging spot for performing charging is selected using a charging control device of the present invention. FIG. 2 is a diagram (part 1) for explaining an example of processing executed by the prediction error correction unit in FIG. 1 . FIG. 2 is a diagram (part 2) for explaining an example of processing executed by the prediction error correction unit in FIG. 1 . 1A and 1B are diagrams illustrating an example of a display screen of an on-board control device of a vehicle. 2 is a flowchart showing an example of a control process executed by the charge control device of FIG. 1 . 8 is a flowchart showing an example of a subroutine executed in step S7 of FIG. 7;

The following describes an embodiment of the present invention with reference to the drawings. The charging control method and device 1 of this embodiment predicts the transition of the battery's SOC (State of Charge) from vehicle information of the vehicle V stored in a vehicle database, and sets a first charging threshold that prevents the driving battery (a secondary battery that supplies power to the driving motor of an electric vehicle or hybrid vehicle. Hereinafter, also referred to simply as the battery) from running out of power, and a second charging threshold that is greater than the first charging threshold. Then, a predicted charging wait time is calculated from facility information of charging spots (chargers outside the vehicle) stored in a charging spot database, and when the battery's SOC is smaller than the second charging threshold and greater than the first charging threshold, a charging instruction is output if there is a charging spot with a predicted charging wait time smaller than a predetermined value.

Figure 1 is a block diagram showing an outline of a charging control system S using a charging control device 1 according to an embodiment of the present invention. The charging control device 1 of this embodiment is also an embodiment for implementing a charging control method according to the present invention. The charging control device 1 includes a communication unit 13, the charger 2 includes a communication unit 23, and the in-vehicle control device 3 includes a communication unit 33, and they are capable of transmitting and receiving information to and from each other via a telecommunications network NW such as the Internet. The communication path may be wired or wireless.

The charger 2 is connected between the battery mounted on the vehicle V and the commercial power source provided at the charging spot C, converts the voltage input from the commercial power source to a voltage suitable for charging the battery, and supplies the converted voltage as a charging voltage to the battery. In this embodiment, an example is described in which a single charger 2 with one charging port is connected to a commercial power source as the charging spot C, but the charging spot C may take the form of, for example, multiple chargers 2 with multiple charging ports connected to the commercial power source.

The charger 2 includes a control unit 21 that executes control processing for charging the battery, a sensor 22 that is electrically connected to the battery, and a communication unit 23 that communicates with an external device such as the charging control device 1 or the on-board control device 3.

The control unit 21 has a charge control function that controls the charging of the battery mounted on the vehicle V, and a charge time calculation function that calculates the charging time of the battery. Specifically, when the charger 2 and the vehicle V are electrically connected via a plug of a power supply connector or the like, the control unit 21 acquires the measured SOC value and the detected values of the battery voltage, current, temperature, etc. from the on-board control device 3 by the charge control function, and controls the charging power output from the charger 2 to the battery.

The control unit 21 also switches the charging mode depending on the chargeable capacity of the battery and the outputtable power of the charger 2. The chargeable capacity is the maximum input power that can be input from the charger 2 to the battery when charging the battery, and the outputtable power is the maximum output power that can be output from the charger 2. The charger 2 includes a quick charger with a high outputtable power and a normal charger with a lower outputtable power than the quick charger, and the charging mode is selected depending on the chargeable capacity of the battery. The control unit 21 uses a charging time calculation function to calculate the battery charging time (the time from when charging starts to when it is completed) and the remaining charging time of the battery (the time remaining until charging is completed) depending on the charging mode, and outputs these to the charging control device 1 and the in-vehicle control device 3 via the communication unit 23.

The sensor 22 is, for example, a plug provided on the power supply connector of the charger 2, and in this embodiment, also serves as the communication unit 23. The charger 2 and the battery are electrically connected when the plug of the charger 2 is inserted into the charging port of the vehicle V. When the charger 2 is electrically connected to the battery, the plug as the sensor 22 and the communication unit 23 transmits operation information of the charger 2 to the vehicle V, and receives charging information such as a charging permission signal and a charging command value from the vehicle V, and outputs this to the control unit 21.

The sensor 22 transmits the usage information of the charger 2 to the charging spot database 12 via the communication unit 23 each time the battery is charged. The usage information of the charger 2 includes information such as the date and time when the charger 2 was used, the charging time, the charging capacity, whether or not different vehicles were charged consecutively, and the identification information of the vehicles that were charged.

The on-board control device 3 includes a control unit 31 that executes control processing for charging the battery, a charge capacity detection unit 32 that detects the SOC of the battery, a communication unit 33 that communicates with an external device such as the charge control device 1 or the charger 2, and a display unit 34 for notifying the driver of the vehicle V of information. The battery mounted on the vehicle V is a battery that uses a battery configured by connecting multiple secondary batteries such as lithium ion secondary batteries and nickel-metal hydride secondary batteries.

The control unit 31 transmits information on the current SOC of the battery obtained using the charge capacity detection unit 32 to the charge control device 1 and the charger 2 via the communication unit 33. The information on the current SOC of the battery is used when the charge control device 1 plans a charging plan and when the charger 2 performs charging. The control unit 31 also obtains current location information of the vehicle V using a position detection device such as a GPS (Global Positioning System) receiver (not shown) provided in the on-board control device 3, and transmits the obtained current location information to the charge control device 1 via the communication unit 33. This current location information of the vehicle V is used to identify a reference position when the charge control device 1 plans a charging plan.

Furthermore, the control unit 31 notifies the driver of the vehicle V of the charging command received from the charge control device 1 and the operation information received from the charger 2 using the display unit 34 such as a display. The display unit 34 is, for example, a display device such as a display of a navigation device or a display provided on an instrument panel. When the control unit 31 receives the position information of the charging spot C where charging is to be performed together with the charging command from the charge control device 1, the control unit 31 can present the driver of the vehicle V with guidance information for the charging spot C by displaying the charging spot C on the display unit 34 in a superimposed manner on a map image. When the control unit 31 receives operation information from the charger 2, the remaining charging time of the battery calculated by the charger 2 can be displayed on the display unit 34, thereby presenting the driver of the vehicle V with the time required for charging.

The control unit 31 of this embodiment also has an autonomous driving control function for the vehicle V. The autonomous driving control function is a function that allows the control unit 31 to autonomously control the driving of the vehicle V without relying on the driver's operation. The autonomous driving control function of the control unit 31 includes an autonomous speed control function that autonomously controls the driving speed of the vehicle V and an autonomous steering control function that autonomously controls the steering of the vehicle V. Autonomous control without relying on the driver's operation also includes some operations being performed by the driver. Note that the autonomous driving control function of the control unit 31 is not a required configuration for the present invention, and all operations may be performed by the driver as necessary.

The charge capacity detection unit 32 calculates the current SOC of the battery at a predetermined time interval and outputs the calculation result to the control unit 31. For example, the SOC of the battery is calculated based on the detection values of a current sensor, a voltage sensor, a temperature sensor, etc. (not shown) provided in the on-board control device 3. When the battery is electrically connected to the charger 2 and charging is being performed, the SOC during charging is calculated by integrating the battery charging current using a current sensor. When the charge capacity detection unit 32 detects that the current SOC of the battery has reached a target SOC (e.g., 100%), the control unit 31 sends a command via the communication unit 33 to stop output from the charger 2 to the battery, and ends charging of the battery.

The charging control device 1 includes a vehicle database 11 that accumulates vehicle information such as vehicle identification information, charging history information, and vehicle mileage of the vehicle V stored in association with changes in SOC, a charging spot database 12 that accumulates facility information including equipment information of the charging spot C, usage information, and charging waiting time calculated from the usage status of the charger 2, a communication unit 13 that can communicate with the charger 2 or the on-board control device 3, and a control unit 14 that executes charging control processing. Note that in this embodiment, the vehicle database 11 and the charging spot database 12 are configured to be included in the charging control device 1, but may be configured to be provided, for example, on an external server and accessible via an internet line, etc.

The vehicle database 11 accumulates and periodically updates vehicle information of the vehicle V received from the on-board control device 3 via the communication unit 13. The vehicle information includes identification information such as the vehicle number, chassis number, and model of the vehicle V, as well as information such as the rated capacity of the battery, chargeable capacity, charging frequency, charging location, and other charging history, and the travel distance of the vehicle V stored in association with the SOC transition. In addition to this, the vehicle information may include status information of the vehicle V, such as the position information of the vehicle V, the direction of travel, the vehicle speed, the ON/OFF state of the door locks, the open/closed state of the doors, the seat belt sensor values, and whether or not the vehicle is traveling autonomously. This vehicle information is used when the charging plan unit 141 creates a charging plan.

The charging spot database 12 accumulates and periodically updates facility information for charging spots C received from the chargers 2 via the communication unit 13. The facility information includes facility information such as the location information (latitude and longitude) of the charging spot C, the type of charger 2, the number of chargers, and the available output power, usage information such as the operating rate of the charging spot C, whether it is fully occupied or not, busy periods, the date, time, charging time, charging capacity, whether different vehicles have been charged consecutively, and identification information of the charged vehicles, as well as information such as the charging waiting time calculated from the usage status of the charger 2. The charging waiting time will be described later.

The communication unit 13 communicates with external devices such as the charger 2 or the on-board control device 3 via the telecommunications network NW. The control unit 14 acquires the current usage status of the charging spot C from the charger 2 via the communication unit 13, and acquires the current SOC of the battery from the on-board control device 3 to reflect it in the charging plan. In addition, the charging command from the charging control device 1 is transmitted to the on-board control device 3 via the communication unit 13.

The control unit 14 includes a ROM (Read Only Memory) in which a program for executing the charging control process by the charging control device 1 is stored, a CPU (Central Processing Unit) as an operating circuit that functions as the charging control device 1 by executing the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. As the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU. The charging plan unit 141, the charging plan correction unit 142, the prediction error correction unit 143, the power shortage prevention determination unit 144, and the charging timing determination unit 145 of the control unit 14 realize various functions of the charging control device 1, such as a charging plan function, a prediction error correction function, a power shortage prevention function, and a charging timing determination function, by executing the program stored in the ROM.

The charging plan unit 141 creates a charging plan for the vehicle V based on the vehicle information of the vehicle V acquired from the vehicle database 11 and the facility information of the charging spot C acquired from the charging spot database 12. As described above, the vehicle information of the vehicle V includes information such as the rated capacity of the battery, the chargeable capacity, the charging frequency, the charging location, and other charging history, as well as the travel distance of the vehicle V stored in association with the transition of the SOC. The facility information of the charging spot C also includes information such as the date, time, charging time, and charging capacity when the charger 2 was used, whether different vehicles were charged consecutively, and the identification information of the charged vehicle, as well as information such as the charging waiting time calculated from the usage status of the charger 2. The charging plan unit 141 calculates the predicted transition of the SOC of the battery and the predicted value of the charging waiting time of the charging spot C from these pieces of information. Then, based on the results of this calculation, a charging plan for the vehicle V is created and output to the charging timing determination unit 145.

2 is a graph showing an example of the predicted transition of the battery SOC and the predicted value of the charging waiting time at the charging spot. The dashed-dotted line graph shows the predicted transition of the battery SOC (remaining charge) with respect to elapsed time, and the solid line graph shows the transition of the predicted value of the charging waiting time at the charging spot C with respect to elapsed time. First, the charging planning unit 141 sets a predetermined SOC at which the battery needs to be charged as a first charging threshold. The predetermined SOC at which the battery needs to be charged is a value for preventing the vehicle V from being in a so-called low-power state (SOC 0%), and is not particularly limited, but is a value at which the vehicle V can travel to a certain extent before being in a low-power state, such as SOC 20%. The first charging threshold may be set to any value, or may be set by calculating the travel distance of the vehicle V stored in association with the transition of the SOC obtained from the vehicle database 11, for example.

Next, the charging planning unit 141 sets a predetermined SOC greater than the first charging threshold as the second charging threshold. The predetermined SOC greater than the first charging threshold is not particularly limited, but is a value that the vehicle V can travel to a certain extent before reaching the first charging threshold, such as SOC 35%. The second charging threshold may be set to an arbitrary value, and when the present invention is applied to a commercial vehicle such as a vehicle dispatch service by an unmanned taxi, the amount of charge consumed in one dispatch service (pick-up, transportation to the destination, and return to the waiting station) may be calculated, and the amount of charge consumed in the dispatch service may be added to the first charging threshold to set the second charging threshold. Specifically, when the amount of charge consumed in one dispatch service is calculated to be SOC 10% from the vehicle information of the vehicle V obtained from the vehicle database 11, the amount of charge consumed in one dispatch service is set to SOC 40%, which is the first charging threshold SOC 20% plus the amount of charge consumed in two dispatch services SOC 20%. The charge amount consumed in two vehicle dispatch services is added together because if the first charge threshold value were reached at the end of one vehicle dispatch service, the frequency with which charging commands would be sent would increase, which could result in a decrease in charging efficiency.

When the first and second charging thresholds are set based on the predicted transition of the SOC, the charging planning unit 141 uses the vehicle information of the vehicle V obtained from the vehicle database 11 to calculate the predicted time t1 at which the battery's SOC will reach the second charging threshold and the predicted time t5 at which the battery's SOC will reach the first charging threshold. Then, the predicted time t1 at which the battery's SOC will reach the second charging threshold is set as the charging consideration start time, and the predicted time t5 at which the battery's SOC will reach the first charging threshold is set as the charging consideration end time.

Next, the charging planning unit 141 calculates the traveling position information of the vehicle V from the charging consideration start time t1 to the charging consideration end time t5 from the current position information of the vehicle V acquired from the on-board control device 3 and the traveling route information set for the vehicle V. Then, the charging spot database 12 is searched to detect a charging spot C within a travelable range from the traveling position of the vehicle V, and the charging spot C is identified as a target charging spot C for which a predicted value of the charging wait time is to be calculated. For the identified charging spot C, the charging planning unit 141 calculates a predicted value of the charging wait time from the charging consideration start time t1 to the charging consideration end time t5.

Figure 3 shows an example of a scene in which a predicted charging wait time is calculated based on data on past charging wait times at charging spot C. Figure 3 (A) shows an example of a charging wait time calculated from the past usage status of charger 2 stored in charging spot database 12, and a predicted charging wait time calculated based on these charging wait times. Figure 3 (B) is a diagram for explaining the calculation process of the charging wait time at 9:00. For example, if charging consideration start time t1 is 9:00, the charging planning unit 141 searches for data on past charging wait times at 9:00 stored in the charging spot database 12, calculates an average value from the sum of the past charging wait times, and sets this as the predicted charging wait time.

Figure 3 (B) shows a scene in which the charging waiting time at charging spot C at 9:00 is calculated from the past usage status of charger 2. Note that it takes 30 minutes to charge once using charger 2. On March 1, 2021, there is a vehicle that started charging using charger 2 from 8:45, so the charging waiting time at 9:00 is 15 minutes. Similarly, on March 2, 2021, there is a vehicle that started charging from 8:50, so the charging waiting time is 20 minutes. In contrast, on March 3, 2021, there is no vehicle that is charging using charger 2, so the charging waiting time is 0 minutes. On March 4, 2021, there is a vehicle that started charging from 8:45 and a vehicle that started charging from 9:15 after the vehicle finished charging, so the charging waiting time is 45 minutes. In this way, the charging waiting time can be calculated from the past usage status of charger 2. Note that other known methods may be used as a method for calculating the charging waiting time.

The charging planning unit 141 calculates a predicted value of the charging waiting time from the charging waiting time calculated from the past usage status of the charger 2. For example, to explain the predicted value of the charging waiting time at 9:00, as shown in FIG. 3(A), when the charging waiting times of 15 minutes on March 1, 2021, 20 minutes on March 2, 2021, 0 minutes on March 3, 2021, and 45 minutes on March 4, 2021 are searched, the charging planning unit 141 sets the predicted value of the charging waiting time to 20 minutes, which is the average charging waiting time from March 1, 2021 to March 4, 2021. Note that the predicted value of the charging waiting time may be the average value or the median value of the past charging waiting times, or other known methods may be used. In this way, by using the data on the past usage status of the charging spot C accumulated in the charging spot database 12, an appropriate predicted value of the charging waiting time based on the actual measurement value can be calculated.

Returning to FIG. 2, the charging planning unit 141 calculates the predicted value of the charging wait time, and then calculates the time when the predicted value of the charging wait time becomes smaller than a predetermined value between the charging consideration start time t1 and the charging consideration end time t5. The predetermined value is not particularly limited, but may be set to, for example, 30 minutes, which is the time for which the charger 2 is used each time, or may be set by calculating an estimated time for the battery SOC to change from the second charging threshold to the first charging threshold based on the vehicle information of the vehicle V obtained from the vehicle database 11.

As shown in FIG. 2, the predicted value of the charging waiting time is smaller than a predetermined value (30 minutes in this example) from the charging consideration start time t1 to time t2 and from time t3 to the charging consideration end time t5. On the other hand, the predicted value of the charging waiting time is larger than the predetermined value from time t2 to time t3. Therefore, the charging planning unit 141 outputs a charging instruction to perform charging from the charging consideration start time t1 to time t2 and from time t3 to the charging consideration end time t5. In this way, when the SOC (remaining charge) of the battery is equal to or less than a predetermined threshold, if there is a charging spot where the predicted value of the charging waiting time is smaller than a predetermined value, a charging instruction to perform charging is output, so that the charging waiting time can be prevented from becoming long. In this embodiment, the time t4, at which the predicted value of the charging waiting time is the smallest between the charging consideration start time t1 and the charging consideration end time t5, is set as the recommended charging time. This can further prevent the charging waiting time from becoming long.

Figure 4 is a diagram illustrating a scene in which a charging spot C for charging is selected from among multiple charging spots C. In the scene shown in Figure 4, multiple charging spots C1, C2, and C3, for which predicted charging wait times have been calculated, are present within the driving range of vehicle V (within the dotted line frame) at recommended charging time t4. The predicted charging wait times at recommended charging time t4 are 15 minutes for charging spot C1, 5 minutes for charging spot C2, and 35 minutes for charging spot C3. Multiple charging spots C1 and C2 exist for which the predicted charging wait times are less than the predetermined value of 30 minutes.

In such a case, the charging planning unit 141 calculates the arrival time required for the vehicle V to reach each charging spot C in addition to the predicted charging waiting time. Then, the charging required time required for the vehicle V to start charging is calculated from the sum of the predicted charging waiting time and the arrival time required to reach the charging spot C.

For example, in the scene shown in FIG. 4, if the arrival time T1 to charging spot C1 is 5 minutes and the arrival time T2 to charging spot C2 is 10 minutes, the required charging time at charging spot C1 is 20 minutes, which is the sum of the predicted charging waiting time of 15 minutes and the arrival time of 5 minutes. In contrast, the required charging time at charging spot C2 is 15 minutes, which is the sum of the predicted charging waiting time of 5 minutes and the arrival time of 10 minutes. At this time, the charging plan unit 141 identifies the charging spot C2 with the shortest required charging time as the charging spot C for performing charging and reflects this in the charging plan. This makes it possible to identify the charging spot C with the shortest required charging time, including the time to reach the charging spot C, from among multiple charging spots C with predicted charging waiting times smaller than a predetermined value, thereby further preventing the charging waiting time from becoming long.

When the charging planning unit 141 creates a charging plan including information such as the first charging threshold, the second charging threshold, the charging consideration start time t1, the charging consideration end time t5, the recommended charging time t4, the predicted charging wait time, and the charging spot C where charging will be performed, the charging planning unit 141 outputs the plan to the charging timing determination unit 145. When the recommended charging time t4 arrives based on this charging plan, the charging timing determination unit 145 transmits a charging command to the on-board control device 3.

The charging plan correction unit 142 corrects the charging plan based on the current SOC of the battery received from the on-board control device 3 via the communication unit 13. This is because, depending on the usage environment and usage mode of the battery, the SOC may reach the second charging threshold earlier than the predicted time of reaching the second charging threshold calculated by the charging plan unit 141. Specifically, if the SOC reaches the second charging threshold earlier than the charging consideration start time t1 (predicted time of reaching the second charging threshold) defined in the charging plan, a predicted value of the charging waiting time at the time when the SOC of the battery actually reaches the second charging threshold (hereinafter also referred to as the second charging threshold reaching time or the current time) is calculated, and the charging plan is corrected using the correction value of the charging waiting time calculated by the prediction error correction unit 143 described later. The corrected charging plan is output to the charging timing determination unit 145.

The prediction error correction unit 143 is not an essential component of the present invention and may be omitted as necessary. In this case, the charging plan correction unit 142 calculates a predicted value of the charging wait time at the time when the second charging threshold is reached, and when there is a charging spot C where the predicted value of the charging wait time is smaller than a predetermined value, the charging plan may be corrected so that a charging command can be output at a timing earlier than the recommended charging time t4, and output to the charging timing determination unit 145. As a result, even if the battery's SOC (remaining charge) reaches the second charging threshold earlier than the initial charging plan, charging can be performed while suppressing the charging wait time from becoming longer.

In addition to calculating the predicted value of the charge wait time at the time when the second charge threshold is reached, the charging plan correction unit 142 may recalculate the charging consideration end time t5 (the predicted time when the first charge threshold is reached) and may newly calculate the predicted value of the charge wait time until the charging consideration end time t5 to update the recommended charging time t4. Furthermore, even at a time before the SOC of the battery actually reaches the second charge threshold, the charging plan correction unit 142 may recalculate the charging consideration start time t1, the charging consideration end time t5, the predicted value of the charge wait time from the charging consideration start time t1 to the charging consideration end time t5, and the recommended charging time t4 based on the current SOC of the battery, and may correct the charging plan as appropriate. This allows charging to be performed using a charging plan that reflects the actual SOC of the battery.

When the current SOC of the battery reaches the second charging threshold, the prediction error correction unit 143 executes a correction process for the charging wait time. Specifically, the prediction value of the charging wait time at the current time when the SOC reaches the second charging threshold is compared with the measured value of the actual charging wait time at the charging spot C at the current time obtained from the charger 2 via the communication unit 13, and the correction value of the charging wait time is calculated.

Figure 5A is a graph (upper diagram) showing the charging plan and the progress of the actual SOC of the battery drawn up in the scene shown in Figure 2, and a diagram (lower diagram) for explaining the calculation process of the correction value of the charging wait time. The dashed-dotted line graph in the upper diagram shows the predicted progress of the battery SOC (remaining charge) versus elapsed time calculated when the charging plan was drawn up, and the solid line graph shows the progress of the predicted value of the charging wait time versus elapsed time. In contrast, the dotted line graph shows the progress of the actual SOC of the battery versus elapsed time. The scene shown in Figure 5A is a scene in which the actual SOC of the battery reaches the second charging threshold at time t0, which is earlier than the charging consideration start time t1 set in the charging plan.

In the scene shown in FIG. 5A, the predicted charging wait time Cp0 at the current time t0 when the actual SOC of the battery reaches the second charging threshold is 12 minutes. However, the remaining charging time until the other vehicle at the charging spot C at the current time t0 actually completes charging is 20 minutes, as calculated by the charger 2. This remaining charging time of 20 minutes until the other vehicle currently charging completes charging is set as the measured charging wait time Cm0. Here, if the vehicle V heads to the charging spot C at the current time t0, the actual charging wait time is likely to be longer than the predicted charging wait time Cp0 of 12 minutes. This is because the vehicle itself cannot be charged until the other vehicle currently charging completes charging. Therefore, the prediction error correction unit 143 sets the measured charging wait time Cm0 of 20 minutes as the corrected charging wait time.

5B is different in that there is no other vehicle currently charging at the charging spot C at the current time t0. The predicted charging waiting time Cp0 at the current time t0 when the second charging threshold is reached is 12 minutes, whereas the measured charging waiting time Cm0 is 0 minutes because no other vehicle is charging at the charging spot C at the current time t0. If the vehicle V heads to the charging spot C at the current time t0, the actual charging waiting time is likely to be shorter than the predicted charging waiting time Cp0 of 12 minutes. Therefore, the prediction error correction unit 143 uses the predicted charging waiting time Cp0 of 12 minutes as it is as the corrected charging waiting time. Note that if the measured charging waiting time Cm0 is smaller than the predicted charging waiting time Cp0, the corrected charging waiting time may be the average of the two values. In the case of the scene shown in FIG. 5B, the average of the measured charging waiting time Cm0 of 0 minutes and the predicted charging waiting time Cp0 of 12 minutes, 6 minutes, may be used as the corrected charging waiting time. By using the average of the two values, the charging plan can be revised based on a value that is closer to the actual charging wait time.

In this way, when the predicted value of the charging wait time at the current time t0 when the actual SOC of the battery has reached the second charging threshold is less than the measured value of the charging wait time, the prediction error correction unit 143 uses the measured value of the charging wait time as the correction value of the charging wait time. On the other hand, when the measured value of the charging wait time is less than the predicted value of the charging wait time, the prediction error correction unit 143 uses the predicted value of the charging wait time as is as the correction value of the charging wait time. This makes it possible to correct the error in the charging wait time calculated from the predicted value.

When the prediction error correction unit 143 calculates the correction value of the charging wait time, it determines whether or not the correction value of the charging wait time is smaller than the upper limit of the charging wait time. The upper limit of the charging wait time is not particularly limited, but may be, for example, the predicted value of the charging wait time at the recommended charging time t4. This makes it possible to prevent the waiting time from becoming longer than the charging wait time at the recommended charging time t4 set in the charging plan.

In the scene shown in FIG. 5A, the corrected value of the charging wait time at the current time t0 is 20 minutes, while the predicted value of the charging wait time at the recommended charging time t4 is 15 minutes. On the other hand, in the scene shown in FIG. 5B, the corrected value of the charging wait time at the current time t0 is 12 minutes, while the predicted value of the charging wait time at the recommended charging time t4 is 15 minutes. In such a case, the prediction error correction unit 143 determines that the corrected value of the charging wait time is smaller than the upper limit value of the charging wait time.

If it is determined that the corrected value of the charging wait time is smaller than the upper limit of the charging wait time, the prediction error correction unit 143 determines whether the increase in the charging wait time after the current time t0 is greater than a predetermined value. This is because if the increase in the charging wait time after the current time t0 is large, it is better to perform charging at the current time t0. The predetermined value for the increase in the charging wait time is not particularly limited, but may be set to any time, such as 10 minutes, or may be set to an increase obtained by comparing the measured value of the charging wait time at the current time t0 with the predicted value of the charging wait time at the recommended charging time t4. This makes it possible to perform charging while taking into account the possibility that the charging wait time after the current time t0 will be longer.

In the scene shown in FIG. 5B, the increase of 15 minutes obtained by comparing the measured charging wait time Cm0 at the current time t0 of 0 minutes with the predicted charging wait time Cp4 of 15 minutes at the recommended charging time t4 is set as the predetermined value. The increase of 12 minutes obtained by comparing the corrected charging wait time at the current time t0 of 12 minutes with the predicted charging wait time Cp1 of 28 minutes after the current time t0, for example at time t1, is 16 minutes. In other words, the increase of 16 minutes in the charging wait time after the current time t0 is greater than the predetermined value of 15 minutes. In such a case, the prediction error correction unit 143 determines that the increase in the charging wait time after the current time t0 is greater than the predetermined value.

If the corrected value of the charging wait time is smaller than the upper limit of the charging wait time and the increase in the charging wait time after the current time t0 is larger than a predetermined value, the prediction error correction unit 143 transmits the calculation result to the charging plan correction unit 142 in order to output a charging command at a timing earlier than the recommended charging time t4. The charging plan correction unit 142 receives this, corrects the charging plan, and outputs it to the charging timing determination unit 145. This makes it possible to correct the prediction error of the charging wait time calculated from the past usage status of the charging spot C based on the current usage status of the charging spot C.

The power shortage prevention determination unit 144 monitors the SOC of the battery so that the vehicle V does not run out of power. Specifically, when the current SOC of the battery received from the on-board control device 3 via the communication unit 13 reaches the first charging threshold, a charging command is sent to the charging timing determination unit 145 along with a signal indicating that the first charging threshold has been reached. This is because when the SOC reaches the first charging threshold, it is better to perform charging regardless of the predicted value of the charging wait time described above. This makes it possible to prevent the vehicle V from running out of power.

The charging timing determination unit 145 transmits a charging command to the on-board control device 3 via the communication unit 13 based on the charging plan received from the charging plan unit 141, the corrected charging plan received from the charging plan correction unit 142, and the charging command received from the power shortage prevention determination unit 144. The on-board control device 3 that receives this transmits an autonomous driving control of the vehicle V based on a command signal from the control unit 31, and drives the vehicle V to the charging spot C where charging is to be performed.

The on-board control device 3 may notify the driver of the vehicle V of the charging action based on the charging command received from the charging timing determination unit 145. Each of Figures 6 (A) and (B) is a diagram showing an example of a display screen on which the charging command is displayed on the on-board control device 3 of the vehicle V. The image shown is displayed on the display of a navigation device serving as the display unit 34 provided in the on-board control device 3.

6A shows an example of a display image when the recommended charging time t4 set in the charging plan is reached. The display image may be in any form, but may display, for example, a message suggesting charging such as "The charging spot is not crowded, so would you like to charge?" along with the battery's SOC (charge remaining amount) and answer buttons such as "Yes/No". In contrast, the display example shown in FIG. 6B shows an example of a display image when the SOC reaches the first charging threshold before the recommended charging time t4. In this case, in order to charge the vehicle V regardless of the predicted charging waiting time, a message encouraging charging such as "The remaining charge is low, so please head to a charging spot" is displayed along with the battery's SOC (charge remaining amount). In this way, the driver of the vehicle V can be prompted to take appropriate charging action by displaying the display mode according to the battery's SOC, such as allowing the driver to select whether or not to charge until the SOC reaches the second charging threshold to the first charging threshold, and forcing charging when the SOC is lower than the first charging threshold.

Next, an example of the charge control process executed by the charge control device 1 will be described using the scenes shown in Figures 5A and 5B as an example. Figure 7 is a flowchart showing an example of the charge control process executed by the charge control device 1. Figure 8 shows a subroutine of step S7 shown in Figure 7.

The charging control process described below is executed by the charging control device 1 at a predetermined time interval, for example, when the main power switch of the vehicle V is turned on. In addition, in the following, it is assumed that the vehicle V is performing autonomous driving control by the autonomous driving control function of the on-board control device 3.

In steps S1 to S5 of FIG. 7, the charging plan unit 141 creates a charging plan for the battery. First, in step S1, a predetermined SOC that prevents the vehicle V from running out of power is set as the first charging threshold. Next, a predetermined SOC that is greater than the first charging threshold is set as the second charging threshold, and the process proceeds to step S2. The predetermined SOC that is greater than the first charging threshold is a value that allows the vehicle V to travel a certain distance before the first charging threshold is reached, such as an SOC of 35%.

In step S2, the predicted time when the battery's SOC will reach the second charging threshold is calculated and set as the charging consideration start time t1. In the following step S3, the predicted time when the battery's SOC will reach the second charging threshold is calculated and set as the charging consideration end time t5.

In step S4, a predicted value of the charging waiting time at charging spot C from charging consideration start time t1 to charging consideration end time t5 is calculated. The predicted value of the charging waiting time is calculated based on the charging waiting time calculated from the past usage status of charging spot C.

In the next step S5, the time at which the predicted charging wait time becomes smaller than a predetermined value between the charging consideration start time t1 and the charging consideration end time t5 is calculated. The predetermined value is, for example, 30 minutes, which is the time it takes to use the charger 2 at one time. Based on the calculation result, the charging planning unit 141 sets the time t4 at which the predicted charging wait time is the smallest as the recommended charging time.

In step S6, the charging plan correction unit 142 determines whether the current SOC of the battery is smaller than the second charging threshold, and if the SOC is smaller than the second charging threshold, proceeds to step S7. In response to this, step S6 is repeated for a predetermined time until the SOC becomes smaller than the second charging threshold. In step S7, a correction process for the charging wait time, which will be described later, is executed.

When the charging wait time correction process is executed in step S7, in the following step S8, the prediction error correction unit 143 determines whether or not the corrected value of the charging wait time is smaller than the upper limit of the charging wait time. If it is determined that the corrected value of the charging wait time is smaller than the upper limit of the charging wait time, the process proceeds to step S9. In contrast, if it is determined that the corrected value of the charging wait time is not smaller than the upper limit of the charging wait time, the process proceeds to step S11. The upper limit of the charging wait time is set to, for example, the predicted value of the charging wait time at the recommended charging time t4.

If it is determined in step S8 that the corrected value of the charging wait time is smaller than the upper limit of the charging wait time, in step S9, it is determined whether the increase in the charging wait time after the current time t0 when the second charging threshold is reached is greater than a predetermined value. The predetermined value of the increase in the charging wait time is set to, for example, the increase obtained by comparing the measured value of the charging wait time at the current time t0 with the predicted value of the charging wait time at the recommended charging time t4.

If the result of the determination in step S9 is that the increase in the charging wait time after the current time t0 is greater than the predetermined value, the charging wait time is less likely to be longer if charging is performed at the current time t0, so the process proceeds to step S10 and a charging command is output.

If it is determined in step S8 that the corrected value of the charging wait time is not smaller than the upper limit of the charging wait time, then in step S11 it is determined whether the current SOC of the battery is smaller than the first charging threshold.

If it is determined in step S11 that the battery's current SOC is less than the first charging threshold, the process proceeds to step S10 and a charging command is output to prevent the vehicle V from running out of power.

In contrast, if the result of the judgment in step S9 is that the increase in the charging wait time since the current time t0 is not greater than the predetermined value, and if the result of the judgment in step S11 is that the current SOC of the battery is not less than the first charging threshold, then in step S12 it is judged whether or not it is the recommended charging time t4. If it is judged that it is the recommended charging time t4, the process proceeds to step S10 and a charging command is output. In response to this, step S12 is repeated for a predetermined time until it is the recommended charging time t4.

In step S7 in FIG. 7, the charging wait time correction process shown in FIG. 8 is executed. First, in step S71, a predicted value of the charging wait time at the current time t0 when the battery SOC actually reaches the second charging threshold is calculated, and the process proceeds to step S72.

In step S72, the prediction error correction unit 143 obtains the measured value of the charging waiting time at the current time t0. The measured value of the charging waiting time is calculated based on the remaining charging time until the other vehicle currently charging at charging spot C completes charging.

In the next step S73, the predicted value of the charging wait time at the current time t0 when the battery SOC has reached the second charging threshold is compared with the actual measured value of the charging wait time at charging spot C at the current time t0 to calculate a correction value of the charging wait time. As shown in FIG. 5A, when the predicted value of the charging wait time is less than the measured value of the charging wait time, the prediction error correction unit 143 sets the measured value of the charging wait time as the correction value of the charging wait time. On the other hand, as shown in FIG. 5B, when the measured value of the charging wait time is less than the predicted value of the charging wait time, the prediction value of the charging wait time is set as the correction value of the charging wait time, and the process proceeds to step S8.

As described above, according to the charging control method and charging control device 1 of this embodiment, a first charging threshold at which the driving battery needs to be charged and a second charging threshold at which the SOC (remaining charge) is greater than the first charging threshold are set, the SOC (remaining charge) is detected and compared with the first and second charging thresholds, and if the SOC (remaining charge) is smaller than the second charging threshold but greater than the first charging threshold, and there is a charging spot C where the predicted charging wait time is less than a predetermined value, a charging instruction to perform charging is output. This makes it possible to prevent the charging wait time from becoming long when the remaining charge of the driving battery is equal to or less than the predetermined threshold.

In addition, according to the charging control method and charging control device 1 of this embodiment, when the SOC (remaining charge) becomes smaller than the second charging threshold, a predicted charging wait time at the charging spot C is calculated, and when there is a charging spot C where the predicted charging wait time is smaller than a predetermined value, a charging instruction is output. Therefore, even if the SOC (remaining charge) of the battery reaches the second charging threshold earlier than the initial charging plan, charging can be performed while suppressing the charging wait time from becoming long.

In addition, according to the charging control method and charging control device 1 of this embodiment, when the SOC (sufficient charge) is less than the first charging threshold, a charging instruction is output regardless of the charging waiting time, so that the vehicle V can be prevented from running out of power.

In addition, according to the charging control method and charging control device 1 of this embodiment, the output display of the charging instruction when the SOC (remaining charge) is smaller than the second charging threshold and larger than the first charging threshold is different from the output display of the charging instruction when the SOC (remaining charge) is smaller than the first charging threshold. By using a display mode according to the SOC (remaining charge) of the battery, such as allowing the driver to choose whether or not to charge when the SOC (remaining charge) is between the second charging threshold and the first charging threshold, and forcing charging when the SOC (remaining charge) is smaller than the first charging threshold, the driver of the vehicle V can be encouraged to take appropriate charging action.

In addition, according to the charging control method and charging control device 1 of this embodiment, a charging instruction is output to the on-board control device 3 of the vehicle V, so that the vehicle V can be smoothly charged by autonomous driving.

Furthermore, according to the charging control method and charging control device 1 of this embodiment, when there are multiple charging spots C with predicted charging wait times smaller than a predetermined value, the driving time required for the vehicle V to reach each charging spot C is calculated, the charging time required is calculated as the sum of the charging wait time at the charging spot C and the driving time required to reach the charging spot, the charging spot C with the shortest charging time is searched for, and a charging instruction is output. This makes it possible to identify the charging spot C with the shortest charging time, including the time to reach the charging spot C, from among multiple charging spots C with predicted charging wait times smaller than a predetermined value, thereby further preventing the charging wait time from becoming long.

Furthermore, according to the charging control method and charging control device 1 of this embodiment, a correction value of the charging wait time is calculated from a predicted value of the charging wait time at the current time t0 when the SOC (remaining charge) becomes the second charging threshold value and a measured value of the charging wait time at the current time t0 calculated from the time until another vehicle currently charging at the charging spot C completes charging, and a charging instruction is output if the correction value of the charging wait time is smaller than the upper limit value of the charging wait time and the increase in the charging wait time since the current time t0 is greater than a predetermined value. This makes it possible to correct the prediction error of the charging wait time calculated from the past usage status of the charging spot C based on the current usage status of the charging spot C.

In addition, according to the charging control method and charging control device 1 of this embodiment, if the measured value of the charging wait time at the current time t0 is greater than the predicted value of the charging wait time at the current time t0, the corrected value of the charging wait time is set as the measured value of the charging wait time, so that the error in the charging wait time calculated from the predicted value can be corrected.

In addition, according to the charging control method and charging control device 1 of this embodiment, the upper limit of the charging wait time is calculated based on the minimum value of the predicted value of the charging wait time from the predicted time t1 when the SOC (remaining charge) becomes the second charging threshold to the predicted time t5 when the SOC becomes the first charging threshold, so it is possible to prevent the waiting time from being longer than the charging wait time at the recommended charging time t4 set in the charging plan.

In addition, according to the charging control method and charging control device 1 of this embodiment, the increase in the charging wait time after the current time t0 is calculated based on the increase obtained by comparing the measured value of the charging wait time at the current time t0 with the minimum predicted value of the charging wait time from the predicted time t1 when the SOC (remaining charge) becomes the second charging threshold to the predicted time t5 when the SOC becomes the first charging threshold. This makes it possible to perform charging while taking into account the possibility that the charging wait time after the current time t0 will be longer.

In addition, according to the charging control method and charging control device 1 of this embodiment, the predicted charging waiting time at charging spot C is calculated based on the past usage status of charging spot C, so that it is possible to calculate an appropriate predicted charging waiting time based on the actual measured value.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

S...Charging control system 1...Charging control device 11...Vehicle database 12...Charging spot database 13...Communication unit 14...Control unit 2...Charger 21...Control unit 22...Sensor 23...Communication unit 3...In-vehicle control device 31...Control unit 32...Charging capacity detection unit 33...Communication unit 34...Display unit V...Vehicle C...Charging spot NW...Telecommunication line network

Claims (11)

A charging control method for issuing a charging instruction based on a remaining charge of a driving battery mounted on a vehicle and a charging waiting time calculated from a usage status of a charging spot, comprising:
setting a first charge threshold at which the driving battery needs to be charged and a second charge threshold at which the remaining charge amount is greater than the first charge threshold;
Detecting the remaining charge and comparing it with the first charge threshold and the second charge threshold;
a charging control method for outputting a charging instruction to perform charging when a charging spot having a predicted charging wait time less than a predetermined value is present when the remaining charge amount is less than the second charging threshold value and greater than the first charging threshold value,
At a current time when the remaining charge amount reaches the second charge threshold value,
calculating a correction value of the charging waiting time from a predicted value of the charging waiting time at the current time and a measured value of the charging waiting time at the current time calculated from a time until another vehicle currently charging at the charging spot completes charging, the measured value being calculated by the charging spot and acquired from the charging spot;
a charging control method that outputs the charging instruction at the current time when the revised value of the charging wait time is smaller than an upper limit value of the charging wait time and an increase in a predicted value of the charging wait time after the current time relative to a measured value of the charging wait time at the current time is greater than a predetermined value. When the remaining charge amount becomes smaller than the second charge threshold value,
Calculating a predicted value of the charging waiting time at the charging spot;
The method for controlling charging according to claim 1 , wherein the charging instruction is output when there is a charging spot where the predicted charging waiting time is smaller than a predetermined value. The charging control method according to claim 1 or 2, wherein when the remaining charge level is less than the first charging threshold, the charging instruction is output regardless of the charging wait time. outputting and displaying the instruction to charge when the remaining charge amount is smaller than the second charge threshold value and larger than the first charge threshold value;
4. The method for controlling charging according to claim 1, wherein the display mode of the output indication of the charging instruction when the remaining charge amount is smaller than the first charging threshold is different from the display mode of the output indication of the charging instruction when the remaining charge amount is smaller than the first charging threshold. The charging control method according to any one of claims 1 to 4, wherein the charging instruction is output to an on-board device of the vehicle. When there are a plurality of charging spots whose predicted charging waiting time is smaller than a predetermined value,
Calculating a travel time required for the vehicle to arrive at each of the charging spots;
calculating a charging required time that is the sum of the charging waiting time at the charging spot and a driving time required to arrive at the charging spot;
6. The charge control method according to claim 1, further comprising: searching for a charge spot that minimizes the required charging time; and outputting the charge instruction. The charging control method according to any one of claims 1 to 6, wherein if the measured value of the charging wait time at the current time is greater than the predicted value of the charging wait time at the current time, the corrected value of the charging wait time is set as the measured value of the charging wait time. The charging control method according to any one of claims 1 to 7, wherein the upper limit of the charging waiting time is calculated based on the minimum predicted value of the charging waiting time from the predicted time when the remaining charge amount reaches the second charging threshold to the predicted time when the remaining charge amount reaches the first charging threshold. The charge control method according to any one of claims 1 to 8, wherein the increase in the charging wait time from the current time onwards is calculated based on the increase obtained by comparing the measured charging wait time at the current time with the minimum predicted charging wait time from the predicted time when the remaining charge reaches the second charging threshold to the predicted time when the remaining charge reaches the first charging threshold. The charging control method according to any one of claims 1 to 9, wherein the predicted charging waiting time at the charging spot is calculated based on past usage of the charging spot. A charging control device including a processor that issues a charging instruction based on a remaining charge of a driving battery mounted on a vehicle and a charging waiting time calculated from a usage status of a charging spot,
The processor,
setting a first charge threshold at which the driving battery needs to be charged and a second charge threshold at which the remaining charge amount is greater than the first charge threshold;
Detecting the remaining charge and comparing it with the first charge threshold and the second charge threshold;
When the remaining charge amount is smaller than the second charge threshold value and larger than the first charge threshold value, if there is a charging spot where the predicted charging waiting time is smaller than a predetermined value, outputting a charging instruction to perform charging;
At a current time when the remaining charge amount reaches the second charge threshold value,
calculating a correction value of the charging waiting time from a predicted value of the charging waiting time at the current time and a measured value of the charging waiting time at the current time calculated from a time until another vehicle currently charging at the charging spot completes charging, the measured value being calculated by the charging spot and acquired from the charging spot;
a charging control device that outputs the charging instruction at the current time when the corrected value of the charging wait time is smaller than an upper limit value of the charging wait time and an increase in the predicted value of the charging wait time after the current time relative to the measured value of the charging wait time at the current time is greater than a predetermined value.

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