JP7469957B2 - Power transmission system and vehicle - Google Patents

Description

The present invention relates to a power transmission system for transmitting power between vehicles and a vehicle.

Patent Document 1 discloses a technology for contactlessly transmitting and receiving battery power between vehicles when multiple vehicles are traveling in a convoy.

JP 2013-70514 A

When charging batteries at a charging spot while traveling in a convoy to a destination, differences in battery SOC between vehicles can result in lost time during charging at the charging spot. For example, a vehicle with a relatively high battery SOC may finish rapid charging early, and charging will switch to a normal slow speed and continue until rapid charging of a vehicle with a relatively low battery SOC is completed. In other words, even if rapid charging is completed early, the vehicle must wait until charging of the other vehicle is completed, and waiting time is wasted.

The present invention aims to provide a power transmission system and vehicle that can reduce the time lost during charging while traveling in a convoy.

In order to solve the above problems, the power transmission system of the present invention includes a power transmission and reception unit that transmits and receives battery power non-contact between vehicles traveling in a platoon, in which multiple vehicles travel in a file, and a power transmission control unit that obtains the number of available vehicles among the multiple vehicles traveling in the platoon that can have their batteries charged at an external charging facility, and transmits and receives power between the vehicles traveling in the platoon so as to level out the SOC of the batteries of a number of vehicles corresponding to the number of available vehicles.When the number of available charging facilities is less than the number of vehicles traveling in the platoon and is two or more, the power transmission control unit targets a number of vehicles equal to the number of available charging facilities for leveling .

The power transmission control unit may also target vehicles for leveling in order of the number of vehicles available at the charging facility, starting with the vehicle with the lowest current battery SOC.

In order to solve the above problems, the vehicle of the present invention is a vehicle that travels in a convoy, in which multiple vehicles travel in a line, and is equipped with a power transmission and reception unit that contactlessly transmits and receives battery power between other vehicles traveling in the convoy, and a power transmission control unit that obtains the number of available vehicles among the multiple vehicles traveling in the convoy that can have their batteries charged at charging equipment outside the vehicle, and transmits and receives power between the vehicles traveling in the convoy so as to level out the SOC of the batteries of a number of vehicles corresponding to the number of available vehicles, and when the number of available vehicles in the charging equipment is less than the number of vehicles traveling in the convoy and is two or more, the power transmission control unit targets a number of vehicles equal to the number of available vehicles in the charging equipment for leveling .

The present invention makes it possible to reduce the time lost due to charging while traveling in a convoy.

1 is a schematic diagram showing a configuration of a power transmission system according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a configuration of a vehicle. FIG. 2 is a diagram illustrating an overview of a power transmission control unit. 5 is a flowchart illustrating the flow of operations of a power transmission control unit.

The following describes in detail an embodiment of the present invention with reference to the attached drawings. The dimensions, materials, and other specific values shown in the embodiment are merely examples to facilitate understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements that have substantially the same function and configuration are given the same reference numerals to avoid duplicated explanations, and elements that are not directly related to the present invention are not illustrated.

FIG. 1 is a schematic diagram showing the configuration of a power transmission system 1 according to the present embodiment. The power transmission system 1 includes a plurality of vehicles 10 that travel in a platoon and a charging spot 12. Platooning refers to a state in which a plurality of vehicles 10 travel in a line (in a platoon). In platooning, other vehicles 10 that are not related to the platoon may be present between the plurality of vehicles 10, and there may be a large distance between the plurality of vehicles 10. In addition, platooning is not limited to a mode in which the vehicles 10 travel in the same lane, and the plurality of vehicles 10 may be present across multiple lanes. In other words, platooning is a mode in which the plurality of vehicles 10 that make up the platoon act as the same group.

Figure 1 shows an example of four vehicles 10 traveling in a platoon. Hereinafter, the vehicles 10 constituting the platoon may be referred to as vehicles 10a, 10b, 10c, and 10b to distinguish them from one another. In the example of Figure 1, the platoon is composed of vehicles 10a, 10b, 10c, and 10b in that order as you move from the front of the platoon to the rear. Note that the number of vehicles 10 traveling in a platoon is not limited to four, and may be any number more than one, such as two, three, or five or more.

Vehicle 10a is equipped with battery 14a. Vehicle 10b is equipped with battery 14b. Vehicle 10c is equipped with battery 14c. Vehicle 10d is equipped with battery 14d. Hereinafter, batteries 14a, 14b, 14c, and 14d may be collectively referred to as battery 14.

Vehicle 10 is an automobile that runs on power from a battery 14 installed in the vehicle. For example, vehicle 10 is an electric vehicle whose driving source is a motor. Vehicle 10 may also be a hybrid electric vehicle in which an engine and a motor are installed side by side as driving sources. Vehicle 10 will be described in more detail later.

The charging spot 12 is a location where the battery 14 of the vehicle 10 can be charged. The charging spots 12 are scattered along roads in various locations. The charging spot 12 is provided with one or more charging devices 20, a charging spot communication unit 22, and a charging spot server 24. FIG. 1 shows an example in which four charging devices 20 are provided in the charging spot 12. Note that the number of charging devices 20 is not limited to four, and may be one to three, or five or more. The number of charging devices 20 may also differ depending on the charging spot 12 in each location.

The charging equipment 20 is connected to a power source (not shown). The power source is assumed to be a power system, but may be, for example, a distributed power source such as a fuel cell. The charging equipment 20 is equipped with a charging gun (not shown). When the charging gun is connected to the vehicle 10, the charging equipment 20 can convert the power of the power source and supply it to the battery 14 of one vehicle 10 through the charging gun. In other words, the charging equipment 20 is equipment that can charge the battery 14 from outside the vehicle.

The charging spot communication unit 22 can establish communication with the outside of the charging spot 12. For example, the charging spot communication unit 22 can wirelessly communicate with the vehicle 10.

The charging spot server 24 is composed of a semiconductor integrated circuit including a central processing unit (CPU), a ROM in which programs and the like are stored, and a RAM as a work area. The charging spot server 24 functions as a charging equipment management unit 26 by executing a program.

The charging equipment management unit 26 communicates with each of the charging equipment 20 and manages the usage status of the charging equipment 20. For example, the charging equipment management unit 26 manages whether each of the charging equipment 20 is in use (charging the battery 14), is not in use and is available (empty state), or is unavailable due to a malfunction or the like (unavailable state).

The charging equipment management unit 26 also estimates the planned charging end time for each charging equipment 20 based on the battery's SOC (State Of Charge) at the start of charging, and manages the usage time of the charging equipment 20.

The charging equipment management unit 26 can also communicate with the vehicle 10 via the charging spot communication unit 22. The charging equipment management unit 26 can communicate with the vehicle 10 and accept reservations for use of the charging equipment 20. In other words, the charging equipment management unit 26 can manage the charging schedule for each charging equipment 20.

For example, if the vehicle 10 intends to use the charging spot 12 in one hour, the passenger of the vehicle 10 causes the vehicle 10 to transmit inquiry information to the charging equipment management unit 26 inquiring about the availability of the charging equipment 20 at the charging spot 12 in one hour. The charging equipment management unit 26 transmits availability information indicating the number of available charging equipment 20 in one hour to the vehicle 10 through the charging spot communication unit 22 based on the charging schedule of each charging equipment 20. When the vehicle 10 receives the availability information, it presents the number of available charging equipment 20 to the passenger. When the passenger of the vehicle 10 accepts the presented number of available charging equipment, the vehicle 10 causes the charging equipment management unit 26 to transmit reservation request information requesting a reservation for use of the charging equipment 20. When the charging equipment management unit 26 receives the reservation request information, it reflects the reservation in the charging schedule, transmits reservation completion information indicating the completion of the reservation to the vehicle 10, and does not accept charging by other vehicles 10 at that time. In this manner, the use of the charging equipment 20 can be reserved.

Figure 2 is a schematic diagram showing the configuration of the vehicle 10. In addition to the battery 14, the vehicle 10 includes a motor 30, an inverter 32, a charging unit 34, a power transmission/reception unit 36, a vehicle communication unit 38, a navigation device 40, and a vehicle control unit 42.

The motor 30 is, for example, a synchronous motor or an induction motor. The rotating shaft of the motor 30 is connected to the wheels through an axle. The inverter 32 converts the power of the battery 14 and supplies it to the motor 30. The motor 30 consumes the power supplied from the battery 14 through the inverter 32 to rotate the wheels. The motor 30 can also function as a generator in response to the rotation of the wheels during deceleration, etc. The inverter 32 can regenerate the power generated by the motor 30 and store it in the battery 14.

The charging unit 34 includes a charging plug that can be connected to a charging gun of the charging equipment 20 outside the vehicle. The charging plug of the charging unit 34 is connected to the battery 14. When the charging gun is connected to the charging plug, the charging unit 34 supplies the power received from the charging equipment 20 to the battery 14. In other words, in the vehicle 10, the battery 14 can be charged (external charging) through the charging unit 34.

The power transmitting and receiving unit 36 is connected to the battery 14. For example, two power transmitting and receiving units 36 are provided, and are arranged near the front bumper and the rear bumper of the vehicle 10. The power transmitting and receiving units 36 can transmit and receive power from the battery 14 between the vehicles 10 traveling in a platoon in a non-contact manner. Specifically, the power transmitting and receiving units 36 can convert the power of the battery 14 into high-frequency AC power and radiate it toward the vehicle 10 outside the vehicle. The power transmitting and receiving units 36 can also receive the power radiated into space, convert it into DC power, and supply it to the battery 14.

In the power transmission system 1, power can be shared between the vehicles 10 that make up the platoon by transmitting power through the power transmission/reception unit 36.

For example, when transmitting power from the vehicle 10 at the front of the platoon to the vehicle 10 at the rear, the vehicle 10 at the front radiates power from the rear power transmitter/receiver 36. The vehicle 10 at the rear receives the power radiated from the vehicle 10 at the front power transmitter/receiver 36. This allows a portion of the power from the battery 14 of the vehicle 10 at the front to be shared with the battery 14 of the vehicle 10 at the rear.

For example, when transmitting power from the rear vehicle 10 to the front vehicle 10 in the platoon, the rear vehicle 10 radiates power forward from the front power transmitter/receiver 36. The front vehicle 10 receives the power radiated rearward from the rear vehicle 10 at the rear power transmitter/receiver 36. This allows a portion of the power from the battery 14 of the rear vehicle 10 to be shared with the battery 14 of the front vehicle 10.

Hereinafter, transmitting power between such vehicles 10 may be referred to as inter-vehicle power transmission. In addition, the vehicle 10 on the power transmitting side in inter-vehicle power transmission may be referred to as the power transmitting vehicle, and the vehicle 10 on the power receiving side may be referred to as the power receiving vehicle.

When performing inter-vehicle power transfer, the inter-vehicle distance may be adjusted so that the power transmitting vehicle and the power receiving vehicle are closer to each other. For example, if there is another vehicle (an intermediate vehicle) between the power transmitting vehicle and the power receiving vehicle, the order of the platoon may be temporarily changed so that the power transmitting vehicle and the power receiving vehicle are adjacent to each other at the front and rear of the platoon, and then inter-vehicle power transfer may be performed. By changing the order of the platoon, energy loss during power transmission and reception can be reduced.

When there is an intermediate vehicle between the power transmitting vehicle and the power receiving vehicle, power transmission between the vehicles may be performed via the intermediate vehicle. For example, the power transmitting vehicle transmits power to the intermediate vehicle. The intermediate vehicle transmits the received power as is to the power receiving vehicle. The power receiving vehicle then receives power from the intermediate vehicle. In this mode, power is transmitted and received twice via the intermediate vehicle, so there is a risk of increased energy loss compared to a mode in which the order of the platoon is changed. However, power can be shared even when there is no space to change the order of the platoon.

The vehicle communication unit 38 can establish communication with communication devices outside the vehicle. For example, the vehicle communication unit 38 can wirelessly communicate with the charge spot server 24 through the charge spot communication unit 22. The vehicle communication unit 38 can also wirelessly communicate between vehicles through the vehicle communication units 38 of other vehicles. The vehicle communication unit 38 can also communicate with communication devices connected to various networks such as the Internet or a mobile phone network.

The navigation device 40 can acquire map information showing a map and traffic information showing congestion or traffic regulations through the vehicle communication unit 38. The navigation device 40 has an input/output unit 44. The input/output unit 44 is, for example, a touch panel display. The input/output unit 44 accepts input operations by passengers of the vehicle 10. The input/output unit 44 can also display various types of information such as map information or traffic information.

The navigation device 40 can obtain the departure point and destination through input operations by the passenger through the input/output unit 44. The navigation device 40 can also obtain the current location using a GPS (Global Positioning System). The navigation device 40 can also derive a planned driving route that indicates the route along which the vehicle 10 is planned to travel, based on the departure point, destination, map information, and traffic information. The input/output unit 44 can display the planned driving route by overlaying it on the map information.

The navigation device 40 can also recognize charging spots 12 along or near the planned driving route based on the map information and the planned driving route. The input/output unit 44 can display the charging spots 12 superimposed on the map information. The navigation device 40 can also derive and display the planned driving time to the destination.

The passenger of the vehicle 10 can also preset the charging spot 12 to be used on the way to the destination in the navigation device 40 via the input/output unit 44. At this time, the navigation device 40 may derive and display the planned driving time to the selected charging spot 12. The passenger of the vehicle 10 can also operate the input/output unit 44 to reserve the use of the charging equipment 20 of the set charging spot 12. The navigation device 40 can communicate with the charging spot server 24 via the vehicle communication unit 38 and reserve the use of the charging equipment 20.

The vehicle control unit 42 is composed of a semiconductor integrated circuit including a central processing unit (CPU), a ROM in which programs and the like are stored, and a RAM as a work area. Although detailed explanation is omitted, the vehicle control unit 42 controls the entire vehicle 1, including the drive mechanism, braking mechanism, and steering mechanism. The vehicle control unit 42 also functions as a power transmission control unit 46 by executing a program. The power transmission control unit 46 controls inter-vehicle power transmission.

The power transmission control unit 46 of one vehicle 10 (leader vehicle) that serves as the leader of the platoon is responsible for control of the entire platoon, including the decision of whether to transmit power between vehicles and the decision of the power transmitting vehicle and the power receiving vehicle. The leader vehicle is set in advance by a passenger in one of the vehicles 10. The order in which the leader vehicle is arranged in the platoon is not limited to the front, but may be in the middle or at the rear, etc.

Figure 3 is a diagram illustrating an overview of the power transmission control unit 46. In Figure 3, the double-headed arrow 60 indicates an example of a remaining overall route, which is a planned driving route from the current location to the destination. In the example of Figure 3, a charging spot 12 for charging is set midway along the remaining overall route. The double-headed arrow 62 indicates an example of a pre-charging route, which is a planned driving route from the current location to the charging spot 12. The double-headed arrow 64 indicates an example of a post-charging route, which is a planned driving route from the charging spot 12 to the destination.

As shown in FIG. 3, the destination required SOC, which is the SOC required to travel from the current location to the destination (the SOC required for the remaining overall route), is assumed to be 70%. Of this, the pre-charge required SOC, which is the SOC required to travel from the current location to the charging spot 12 (the SOC required for the route before charging), is assumed to be 20%. Furthermore, the post-charge required SOC, which is the SOC required to travel from the charging spot 12 to the destination (the SOC required for the route after charging), is assumed to be 50%. In FIG. 3, the numbers within the marks (vehicle marks) of each of the vehicles 10a to 10d indicate an example of the SOC of the battery 14 at each timing of each of the vehicles 10a to 10d. For convenience, FIG. 3 will be described assuming that there is no energy loss due to power transmission between the vehicles.

For example, at the timing indicated by the vehicle marks in the top row of Figure 3, it is assumed that at the current location, the SOC of vehicle 10a is 80%, the SOC of vehicle 10b is 70%, the SOC of vehicle 10c is 30%, and the SOC of vehicle 10d is 5%.

The power transmission control unit 46 determines whether all of the vehicles 10 traveling in the platoon can travel to the charging spot 12. Hereinafter, all of the vehicles 10 traveling in the platoon (all of the vehicles 10 that make up the platoon) may be referred to as a group of vehicles.

At the time of the top vehicle mark above, vehicles 10a, 10b, and 10c can travel to the charging spot 12 because their SOC is equal to or greater than the required SOC before charging (20%). However, vehicle 10d cannot reach the charging spot 12 because its SOC is 5%, which is less than the required SOC before charging (20%).

The power transmission control unit 46 then selects the vehicle 10a with the highest SOC (80%) as the power transmitting vehicle and the vehicle 10d with the lowest SOC (5%) as the power receiving vehicle. The power transmission control unit 46 then performs inter-vehicle power transmission as indicated by the dashed arrow 70 in the second row from the top of FIG. 3.

Specifically, the power transmission control unit 46 subtracts the SOC (5%) of the vehicle 10d (receiving vehicle) with the smallest SOC from the required SOC before charging (20%) to derive the amount of received power (15%) to be received by the receiving vehicle (amount of received power = required SOC before charging - SOC of receiving vehicle). The power transmission control unit 46 derives the amount of transmitted power from the amount of received power, taking into account energy loss due to transmission and reception. Note that in the example of FIG. 3, the amount of transmitted power (15%) is derived assuming no energy loss (amount of transmitted power = amount of received power). The power transmission control unit 46 then transmits power equivalent to the derived amount of transmitted power from the transmitting and receiving unit 36 of the transmitting vehicle, and receives power equivalent to the derived amount of received power at the transmitting and receiving unit 36 of the receiving vehicle.

As shown by the vehicle marks in the second row from the top in Figure 3, when the above inter-vehicle power transfer is completed, the SOC of vehicle 10a is 65%, the SOC of vehicle 10b is 70%, the SOC of vehicle 10c is 30%, and the SOC of vehicle 10d is 20%. Then, the group of vehicles including vehicle 10d can reach the charging spot 12.

Incidentally, if the number of available vehicles at charging equipment 20 is equal to or greater than the number of vehicles in the vehicle group, all of the vehicles 10 can be charged at charging spot 12. However, in the example of FIG. 3, the number of available vehicles at charging spot 12 is two, which is less than the number of vehicles in the vehicle group (four). If the number of available vehicles is less than the number of vehicles, it is not possible to charge all of the vehicles 10 at charging spot 12. In such a case, it is estimated that in the future, when charging at charging spot 12, the two vehicles in the vehicle group with the lowest SOC will be charged.

In the state of the vehicle marks in the second row from the top in Figure 3, it is estimated that in the future, two vehicles will be charged at the charging spot 12: vehicle 10d with the lowest SOC (20%) and vehicle 10c with the second lowest SOC (30%). When vehicle 10d reaches the charging spot 12, it is estimated that its SOC will be 0%, and when vehicle 10c reaches the charging spot 12, it is estimated that its SOC will be 10%.

Here, the charging equipment 20 can perform rapid charging of the battery 14 when the SOC is in the range of 0% to 80%. In contrast, when the SOC exceeds 80%, the charging equipment 20 cannot perform rapid charging of the battery 14, and normal charging (charging at a normal speed) is performed. Rapid charging increases the amount of SOC increase per unit time more than normal charging. In other words, normal charging increases the amount of SOC increase per unit time less than rapid charging.

For example, when vehicle 10d with an SOC of 0% and vehicle 10c with an SOC of 10% are charged in parallel at charging spot 12, the SOC of vehicle 10c reaches 80% before the SOC of vehicle 10d. In this case, rapid charging is terminated for vehicle 10c, and normal charging is performed until the SOC of vehicle 10d reaches 80%. In other words, vehicle 10c, which has completed rapid charging first, must wait until the rapid charging of the other vehicle 10d is completed, and the waiting time is wasted.

Therefore, when the number of available charging facilities 20 is less than the number of vehicles in the vehicle group, the power transmission control unit 46 performs inter-vehicle power transmission to equalize the SOC of the batteries 14 of the number of vehicles (two vehicles in the example of FIG. 3) equal to the number of available charging facilities 20. At this time, the power transmission control unit 46 sets the vehicles 10 in the vehicle group that are equal to the number of available charging facilities 20 as the vehicles 10 to be subjected to the above-mentioned equalization (target vehicles), starting from the vehicle 10 with the lowest current SOC of the battery 14.

For example, in the state of the vehicle mark in the second row from the top in Figure 3, there are two available vehicles in the charging facility 20, so the two vehicles 10 that are the target vehicles for leveling are vehicle 10d, which has the lowest SOC (20%) in the vehicle group, and vehicle 10c, which has the second lowest SOC (30%).

The power transmission control unit 46 selects the vehicle 10 (vehicle 10c) with the highest SOC among the vehicles to be leveled (vehicles 10c, 10d) as the power transmitting vehicle, and the vehicle 10 (vehicle 10d) with the lowest SOC as the power receiving vehicle. The power transmission control unit 46 then performs inter-vehicle power transmission as indicated by the dashed arrow 72 in the third row from the top of FIG. 3.

Specifically, assuming that there is no energy loss due to power transmission and reception, the power transmission control unit 46 derives the average value (25%) of the SOC (30%) of the power transmitting vehicle and the SOC (20%) of the power receiving vehicle (average value = (SOC of power transmitting vehicle + SOC of power receiving vehicle) / 2). Next, the power transmission control unit 46 subtracts the SOC (20%) of the power receiving vehicle from the average value (25%) to derive the amount of power received (5%) (amount of power received = average value - SOC of power receiving vehicle). In addition, the amount of power transmitted (5%) is assumed to be equal to the amount of power received (amount of power transmitted = amount of power received). The power transmission control unit 46 then transmits power equivalent to the derived amount of power transmitted from the power transmitting and receiving unit 36 of the power transmitting vehicle, and receives power equivalent to the derived amount of power received by the power transmitting and receiving unit 36 of the power receiving vehicle.

As shown by the vehicle marks in the third row from the top in Figure 3, when the above inter-vehicle power transfer is completed, the SOC of vehicle 10c and the SOC of vehicle 10d are both equal at 25% and are leveled out.

In addition, when there is energy loss due to power transmission and reception, the amount of received power and the amount of transmitted power may be derived as follows. For example, the explanation will be given assuming that the SOC loss is 2%. The power transmission control unit 46 adds the SOC (30%) of the power transmitting vehicle and the SOC (20%) of the power receiving vehicle and subtracts the SOC loss (2%) to derive the effective SOC (48%) (effective SOC = SOC of the power transmitting vehicle + SOC of the power receiving vehicle - SOC loss). Next, the power transmission control unit 46 divides the effective SOC (48%) by the number of vehicles (2) transmitting and receiving power to derive the effective average value (24%) (effective average value = effective SOC / 2). Next, the power transmission control unit 46 subtracts the SOC (20%) of the power receiving vehicle from the effective average value (24%) to derive the amount of received power (4%) (amount of received power = effective average value - SOC of the power receiving vehicle). Next, the power transmission control unit 46 adds the SOC loss (2%) to the amount of received power (4%) to derive the amount of transmitted power (6%) (amount of transmitted power = amount of received power + SOC loss). When this mode of inter-vehicle power transmission is completed, the SOC of vehicle 10c and the SOC of vehicle 10d are both equal at 24%. However, for ease of explanation, the following calculations will be described assuming that there is no energy loss.

Let us assume that the vehicle leaves the current location in the state of the vehicle mark in the third row from the top in Figure 3 and travels to the charging spot 12. Then, the SOC of each vehicle in the group of vehicles will be in the state of the vehicle mark in the fourth row from the top in Figure 3. That is, the SOC of vehicle 10a will be 45%, the SOC of vehicle 10b will be 50%, the SOC of vehicle 10c will be 5%, and the SOC of vehicle 10d will be 5%.

At the charging spot 12, there are two vehicles available in the charging equipment 20, so charging (external charging) is performed on the two vehicles 10c and 10d, starting with the vehicle 10 with the lowest SOC. As shown by the dashed frame 74, vehicles 10c and 10d have the same SOC of 5% when charging begins, so when they are charged in parallel, the SOC reaches 80% at roughly the same time and rapid charging ends. This improves the overall charging efficiency of vehicles 10c and 10d.

When charging at the charging spot 12 is completed, the vehicle will be in the state shown by the vehicle mark in the fifth row from the top in Figure 3. That is, the SOC of vehicle 10a will be 45%, the SOC of vehicle 10b will be 50%, the SOC of vehicle 10c will be 80%, and the SOC of vehicle 10d will be 80%.

Now that charging at the charging spot 12 is complete, the group of vehicles will travel from the charging spot 12 to the destination. The power transmission control unit 46 determines whether the group of vehicles can travel from the charging spot 12 to the destination.

At the timing of the vehicle mark in the fifth row from the top in Figure 3, vehicles 10b, 10c, and 10d can travel to the destination because their SOC is equal to or greater than the required SOC after charging (50%). However, vehicle 10a cannot reach the destination because its SOC is 45%, which is less than the required SOC after charging (50%).

The power transmission control unit 46 then determines the vehicle 10c with the highest SOC (80%) among the group of vehicles as the power transmitting vehicle, and the vehicle 10a with the lowest SOC (45%) as the power receiving vehicle. If the SOCs of multiple vehicles 10 are all highest, for example, the vehicle 10 closest to the power receiving vehicle (vehicle 10c in the example of FIG. 3) is determined as the power transmitting vehicle. The power transmission control unit 46 then transmits power between the vehicles as indicated by the dashed arrow 76 in the sixth row from the top of FIG. 3.

Specifically, the power transmission control unit 46 subtracts the SOC (45%) of the vehicle 10a (receiving vehicle) with the smallest SOC from the required SOC after charging (50%) to derive the amount of received power (5%) to be received by the receiving vehicle (amount of received power = required SOC after charging - SOC of receiving vehicle). The power transmission control unit 46 derives the amount of transmitted power from the amount of received power, taking into account energy loss due to transmission and reception. Note that in the example of FIG. 3, the amount of transmitted power is derived assuming no energy loss (amount of transmitted power = amount of received power). The power transmission control unit 46 then transmits power equivalent to the derived amount of transmitted power from the transmitting and receiving unit 36 of the transmitting vehicle, and receives power equivalent to the derived amount of received power at the transmitting and receiving unit 36 of the receiving vehicle.

As shown by the vehicle marks in the sixth row from the top in Figure 3, when the above inter-vehicle power transfer is completed, the SOC of vehicle 10a is 50%, the SOC of vehicle 10b is 50%, the SOC of vehicle 10c is 75%, and the SOC of vehicle 10d is 80%. This allows the group of vehicles to reach the destination from the charging spot 12.

Let us assume that the vehicles depart from the charging spot 12 in the state of the vehicle mark in the sixth row from the top in Figure 3 and travel to the destination. Then, the SOC of each vehicle in the group of vehicles will be in the state of the vehicle mark in the bottom row in Figure 3. That is, the SOC of vehicle 10a will be 0%, the SOC of vehicle 10b will be 0%, the SOC of vehicle 10c will be 25%, and the SOC of vehicle 10d will be 30%. In this manner, the power transmission control unit 46 performs power transmission between the vehicles.

Next, the flow of operation of the power transmission control unit 46 will be described. First, the passenger of the vehicle 10 sets various settings related to platooning through the input/output unit 44. For example, the passenger sets the vehicles 10 that make up the platoon and the leader vehicle. The passenger also sets the departure point, destination, and planned driving route through the input/output unit 44. The passenger also sets whether or not to charge at a charging spot 12 on the way to the destination. If charging at a charging spot 12, the passenger also sets the location of the charging spot 12 to be used and a reservation for the charging facility 20.

Figure 4 is a flowchart explaining the flow of operation of the power transmission control unit 46. After various settings are completed, the power transmission control unit 46 starts the series of processes in Figure 4. The power transmission control unit 46 repeats the series of processes in Figure 4 at each predetermined interrupt timing that occurs at a predetermined control period until the group of vehicles reaches the destination.

First, the power transmission control unit 46 acquires the current SOC of each battery 14 from each vehicle 10 in the vehicle group via the vehicle communication unit 38 (S100). Next, the power transmission control unit 46 acquires the current location, destination, and planned driving route from the current location to the destination from the navigation device 40, and derives the destination required SOC, which is the SOC required to drive from the current location to the destination, based on the acquired information (driving distance or driving time) (S110).

Next, the power transmission control unit 46 determines whether or not it is set to charge at a charging spot 12 on the way from the current location to the destination (S120). If it is set not to charge at a charging spot 12 (NO in S120), the power transmission control unit 46 determines whether or not it is possible to travel to the destination with the current SOC (S200). For example, the power transmission control unit 46 determines that it is possible to travel to the destination if the current SOC of all vehicles 10 is equal to or greater than the required SOC for the destination.

If all vehicles 10 are capable of traveling to the destination with their current SOC (YES in S200), the power transmission control unit 46 ends the series of processes.

If one or more of the vehicles 10 in the vehicle group cannot travel to the destination with the current SOC (NO in S200), the power transmission control unit 46 determines whether all of the vehicles 10 can travel to the destination if inter-vehicle power transmission is performed (S210). For example, the power transmission control unit 46 derives an average SOC value by averaging the current SOCs of each vehicle 10 by the number of vehicles. The average SOC value may be derived by a predetermined value lower, taking into account energy loss during power transmission and reception. Then, if the derived average SOC value is equal to or higher than the required SOC for the destination, the power transmission control unit 46 determines that travel is possible if inter-vehicle power transmission is performed.

If inter-vehicle power transfer would enable all of the vehicles 10 to travel to the destination (YES in S210), the power transfer control unit 46 transfers power between the vehicles (S220) and ends the process.

Specifically, the power transmission control unit 46 designates the vehicle 10 in the vehicle group with the highest current SOC as the power transmitting vehicle, and the vehicle 10 with the lowest current SOC as the power receiving vehicle. The power transmission control unit 46 then derives the amount of received power and the amount of transmitted power, and causes the power transmitting vehicle and the power receiving vehicle to transmit and receive power.

When the power transmitting vehicle and the power receiving vehicle are not adjacent to each other at the front and rear of the platoon, the power transmission control unit 46 instructs the passenger of the vehicle 10 via the input/output unit 44 or the like to change the order of the platoon. After the passenger who received the instruction changes the order of the platoon, the power transmission control unit 46 causes the power transmitting vehicle and the power receiving vehicle to transmit and receive power. Note that the change of the order of the platoon may be performed by automatic driving.

If all of the vehicles 10 cannot travel to the destination even after inter-vehicle power transfer (NO in S210), the power transfer control unit 46 notifies the input/output unit 44, etc. that a charging spot 12 needs to be set (charging spot 12 needs to be set) (S230), and the series of processes ends.

Also, in step S120, if it is set to charge at the charging spot 12 (YES in S120), the power transmission control unit 46 derives the pre-charging required SOC based on the planned driving route to the charging spot 12 (S300).

Next, the power transmission control unit 46 determines whether all vehicles 10 are capable of traveling to the charging spot 12 with their current SOC (S310).

If one or more of the vehicles 10 in the vehicle group cannot travel to the charging spot 12 with their current SOC (NO in S310), the power transfer control unit 46 determines whether or not the vehicles can travel to the charging spot 12 by transferring power between the vehicles (S320).

If inter-vehicle power transfer allows the vehicle to travel to the charging spot 12 (YES in S320), the power transfer control unit 46 transfers power between the vehicles (S330) and ends the series of processes. Specifically, the power transfer control unit 46 selects the vehicle 10 with the highest current SOC among all the vehicles 10 as the power transmitting vehicle, and the vehicle 10 with the lowest current SOC as the power receiving vehicle. The power transfer control unit 46 then derives the amount of received power and the amount of transmitted power, and causes the power transmitting vehicle and the power receiving vehicle to transmit and receive power.

If all of the vehicles 10 cannot travel to the charging spot 12 even after inter-vehicle power transmission (NO in S320), the power transmission control unit 46 notifies the input/output unit 44, etc. that the charging spot 12 should be reconfigured (S340), and the series of processes ends.

Also, in step S310, if all of the vehicles 10 are capable of traveling to the charging spot 12 with their current SOC (YES in S310), the power transmission control unit 46 determines whether the number of available vehicles in the charging facility 20 is two or more (S400).

If the number of available vehicles in the charging facility 20 is two or more (YES in S400), the power transmission control unit 46 derives the maximum SOC difference by subtracting the minimum value from the maximum value among the current SOCs for the multiple vehicles 10 to be leveled, and determines whether the maximum SOC difference is equal to or greater than a predetermined value (S410). Note that if the number of available vehicles is equal to or greater than the number of vehicles in the vehicle group, the power transmission control unit 46 targets all vehicles 10 in the vehicle group for leveling. Also, if the number of available vehicles is two or more but less than the number of vehicles in the vehicle group, the power transmission control unit 46 targets vehicles 10 in the vehicle group with the lowest SOC as many as the number of available vehicles.

If the maximum SOC difference is equal to or greater than the predetermined value (YES in S410), the power transmission control unit 46 performs power transmission between the vehicles (S420) and ends the series of processes. In other words, since the batteries 14 of multiple vehicles 10 can be charged at the charging spot 12, power is transmitted and received between the number of vehicles 10 corresponding to the number of available spaces.

In addition, if the number of available vehicles in the charging facility 20 is less than two (NO in S400), the power transmission control unit 46 ends the series of processes without performing inter-vehicle power transmission. If the number of available vehicles in the charging facility 20 is one, there is no benefit to be gained from leveling even if inter-vehicle power transmission is performed, so unnecessary inter-vehicle power transmission is avoided. Note that if the number of available vehicles in the charging facility 20 is zero, the charging facility 20 is not reserved in the first place.

If the maximum SOC difference is less than the predetermined value (NO in S410), the power transmission control unit 46 ends the series of processes without performing inter-vehicle power transmission. In this case, inter-vehicle power transmission is not performed because there is a risk that the effect will not be worth the energy loss during power transmission and reception.

As described above, in the power transmission system 1 of this embodiment, the number of available vehicles in the charging facility 20 that can charge the batteries 14 is obtained, and power is transmitted and received between the vehicles 10 traveling in a platoon so as to level out the SOC of the batteries 14 of the number of vehicles 10 corresponding to the number of available vehicles. Therefore, in the power transmission system 1 of this embodiment, when the vehicles 10 are charged at a charging spot 12 along the planned driving route, the rapid charging of the multiple vehicles 10 being charged can be ended at approximately the same timing.

Therefore, the power transmission system 1 and vehicle 10 of this embodiment can reduce the time lost due to charging during platooning.

In addition, in the power transmission system 1 of this embodiment, when the number of available vehicles in the charging facility 20 is less than the number of vehicles traveling in the platoon and is two or more, vehicles 10 whose number is equal to the number of available vehicles in the charging facility 20 are subject to leveling. In the power transmission system 1 of this embodiment, SOC leveling is limited to the vehicles 10 being charged, making it possible to appropriately reduce the time loss required for charging.

In addition, in the power transmission system 1 of this embodiment, vehicles 10 are targeted for leveling in order of the vehicle with the lowest current battery SOC, up to the number of vehicles available in the charging facility 20. This allows the power transmission system 1 of this embodiment to charge to the maximum extent possible using the charging facility 20.

Although an embodiment of the present invention has been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

For example, in the above embodiment, when the number of available vehicles in the charging facility 20 is less than the number of vehicles in the vehicle group and is two or more, the vehicles 10 whose number is equal to the number of available vehicles in the charging facility 20 are subject to leveling, and inter-vehicle power transfer is performed only between the vehicles 10 that are subject to leveling. However, the power transfer control unit may level the vehicles 10 that are subject to leveling by transmitting and receiving power between the vehicles 10 that are subject to leveling and vehicles 10 other than the vehicles that are subject to leveling.

To give a specific example, in the state of the vehicle mark in the second row from the top in FIG. 3, vehicle 10c with an SOC of 30% and vehicle 10d with an SOC of 20% are targeted for leveling. The power transmission control unit 46 transmits and receives 10% of the power from vehicle 10c, which is the target of leveling, to vehicle 10a, which is not the target of leveling. In other words, vehicle 10c maintains the minimum SOC (20%) required for running, and transmits the surplus to vehicle 10a, which is not the target of leveling, to level the target vehicles 10c and 10d. As a result, the SOCs of vehicles 10c and 10d are both 20% and are leveled. According to this aspect, the amount of charge of the quick charge increases compared to the aspect in which power is transmitted and received only between vehicles 10 that are the target of leveling, but the SOC of vehicle 10a other than the vehicle that is the target of leveling can be increased.

Alternatively, the power transmission control unit 46 transmits and receives 10% of the power from the vehicle 10b, which is not the target of the leveling, to the vehicle 10d, which is the target of the leveling. As a result, the SOCs of the vehicles 10c and 10d are both 30%, and are leveled. According to this embodiment, the SOC of the vehicle 10b other than the vehicle that is the target of the leveling decreases compared to the embodiment in which power is transmitted and received only between the vehicles 10 that are the target of the leveling, but the amount of charge of the quick charge can be reduced.

Reference Signs List 1 Power transmission system 10, 10a, 10b, 10c, 10d Vehicle 14, 14a, 14b, 14c, 14d Battery 20 Charging equipment 36 Power transmission/reception unit 46 Power transmission control unit

Claims (3)

a power transmission/reception unit that transmits and receives battery power in a non-contact manner between vehicles that are traveling in a platoon;
a power transmission control unit that acquires the number of available vehicles among the plurality of vehicles traveling in the platoon that can charge the batteries at a charging facility outside the vehicles, and transmits and receives power between the vehicles traveling in the platoon so as to equalize the SOCs of the batteries of a number of vehicles corresponding to the number of available vehicles;
Equipped with
The power transmission control unit, when the number of available vehicles in the charging facility is less than the number of vehicles performing the platooning and is two or more, targets vehicles in a number equal to the number of available vehicles in the charging facility for the leveling . The power transfer system according to claim 1 , wherein the power transfer control unit targets vehicles for the leveling in order from the vehicle with the lowest current SOC of the battery, the number of vehicles being equal to the number of available vehicles in the charging facility. A vehicle that performs platooning in which multiple vehicles travel in a line,
a power transmission/reception unit that transmits and receives battery power in a non-contact manner between the vehicle and other vehicles that are traveling in the platoon;
a power transmission control unit that acquires the number of available vehicles among the plurality of vehicles traveling in the platoon that can charge the batteries at a charging facility outside the vehicles, and transmits and receives power between the vehicles traveling in the platoon so as to equalize the SOCs of the batteries of a number of vehicles corresponding to the number of available vehicles;
Equipped with
The power transmission control unit, when the number of available vehicles in the charging facility is less than the number of vehicles performing the platooning and is two or more, targets a number of vehicles equal to the number of available vehicles in the charging facility for the leveling .

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