Autonomous Vehicle and Charging Method for the Battery of an Autonomous Vehicle

Abstract

To provide an automatic driving vehicle capable of increasing use of electric power generated by sunlight.SOLUTION: An automatic driving vehicle 2 is equipped with a solar cell and a battery that can be charged with electric power generated by the solar cell. The automatic driving vehicle 2 looks for a photovoltaic power generation point where an amount of charging power of the battery increases more than a present location to move by automatic driving to the photovoltaic power generation point.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an autonomous vehicle equipped with a solar cell and a battery that can be charged with electric power generated by the solar cell, and a method for charging the battery of the autonomous vehicle.

Background Art

[0002] Patent Document 1 discloses a vehicle equipped with a solar panel. The vehicle disclosed in Patent Document 1 determines the direction of the solar panel that is estimated to maximize the total power generation during a predetermined period when parked, based on the parking position and the current date and time. Then, the attitude of the vehicle is controlled according to the parking orientation using a suspension device so that the solar panel faces the determined direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Today, in order to promote energy conservation throughout society, it is required to increase the use of electric power generated by sunlight in vehicles. Performing solar power generation in a parked vehicle as described in Patent Document 1 is one way to effectively utilize sunlight. However, when the vehicle is parked in a position where sunlight does not reach, no power generation by sunlight can be performed no matter how the direction of the solar panel is changed.

[0005] The present disclosure has been made in view of the above problems. An object of the present disclosure is to promote energy conservation by increasing the use of electric power generated by sunlight in vehicles.

Means for Solving the Problems

[0006] The present disclosure provides an autonomous vehicle for achieving the above object. The autonomous vehicle of the present disclosure is equipped with a solar cell and a battery that can be charged with the power generated by the solar cell. The autonomous vehicle of the present disclosure is configured to search for a solar power generation point where the amount of charge of the battery increases compared to the current location and to move to the solar power generation point by autonomous driving. According to such a configuration, the use of the power generated by sunlight in the autonomous vehicle can be increased, and energy saving can be promoted.

[0007] The autonomous vehicle of the present disclosure may be configured to determine a solar power generation point based on the weather forecast of the surrounding area. By using the weather forecast, it is possible to predict a place suitable for solar power generation and move the vehicle.

[0008] The autonomous vehicle of the present disclosure may be configured to determine, as a solar power generation point, a place where the illuminance detected by an illuminance sensor is higher than the surroundings. By using the illuminance sensor, the vehicle can automatically search for a place suitable for solar power generation in the vicinity of the vehicle while moving.

[0009] The autonomous vehicle of the present disclosure may be configured to determine a solar power generation point based on an illuminance database in which illuminance data for each time and each location is stored. By using the illuminance database in which past results are accumulated, it is possible to predict a place suitable for solar power generation and move the vehicle.

[0010] The autonomous vehicle of the present disclosure may be configured to identify a non-shaded place based on 3D map data and the date and time, and to determine a solar power generation point from among the non-shaded places. Since the size of the building can be known from the 3D map data and the position of the sun can be known from the date and time, it is possible to accurately predict a non-shaded place suitable for the solar power generation point.

[0011] The autonomous vehicle of the present disclosure is configured to calculate the amount of power generated by a solar cell per predetermined time for each registered location, calculate the amount of power consumed by movement for each registered location, and determine a solar power generation point from among the registered locations based on the difference between the amount of power generated and the amount of power consumed for each registered location. By including the amount of power consumed for movement in the calculation, it is possible to determine whether the benefit of simply moving the vehicle is a location where solar power generation can be obtained.

[0012] The autonomous vehicle of the present disclosure may be configured to perform at least automatic cleaning of the solar cell panels before moving to a solar power generation point. By removing dirt from the solar cell panels through cleaning, the power generation amount can be increased. Preferably, by washing the solar cell panels with water, the temperature of the solar cells can be lowered and the power generation amount can be further increased.

[0013] Further, the present disclosure provides a method for charging a battery of an autonomous vehicle equipped with a solar cell. The charging method of the present disclosure includes searching for a solar power generation point where the amount of power charged in the battery increases compared to the current location of the autonomous vehicle, and automatically moving the autonomous vehicle to the solar power generation point by autonomous driving. According to such a charging method, the utilization of the power generated by sunlight in the autonomous vehicle can be increased, and energy saving can be promoted.

Advantages of the Invention

[0014] As described above, according to the autonomous vehicle of the present disclosure and the method for charging the battery of the autonomous vehicle, energy saving can be promoted by increasing the utilization of the power generated by sunlight in the vehicle.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

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Figure 6

Embodiments for Carrying Out the Invention

[0016] Hereinafter, with reference to the drawings, an autonomous vehicle according to an embodiment of the present disclosure and a battery charging method executed in the autonomous vehicle will be described.

[0017] FIG. 1 shows the system configuration of the autonomous vehicle 2 according to the present embodiment. The autonomous vehicle 2 includes an autonomous driving system 10 capable of autonomous driving at level 4 or higher in the definition of the Society of Automotive Engineers (SAE) of the United States. The autonomous driving system 10 includes external sensors such as cameras and LiDARs that recognize the surrounding situation of the vehicle, vehicle state sensors that detect vehicle states such as acceleration and yaw rate, and one or more ECUs that process the information of these sensors and generate a target trajectory of the vehicle. Since the configuration and functions of the autonomous driving system are well-known and the well-known ones can be applied to the autonomous vehicle 2, the details of the autonomous driving system 10 will be omitted.

[0018] The autonomous vehicle 2 is an electric vehicle (EV) that runs on the power stored in the battery 12. The autonomous vehicle 2 may be not only a battery electric vehicle (BEV), but also a plug-in hybrid vehicle (PHEV) or a hybrid vehicle (HEV). Hereinafter, the autonomous vehicle 2 will be simply referred to as the vehicle 2.

[0019] Vehicle 2 is equipped with a solar cell 20 for generating electric power to be stored in the battery 12. The solar cell 20 is mounted on the roof of the vehicle 2. The solar cell 20 may also be mounted on the bonnet or the trunk. Note that the charging of the battery 12 is performed by charging with an external charging device, power generation by an internal combustion engine, or power regeneration by regenerative braking, in addition to solar power generation by the solar cell 20. For the charging control of the battery 12, the vehicle 2 is equipped with a battery management system 22.

[0020] Vehicle 2 is equipped with a navigation system 24, a communication device 26, and an illuminance sensor 28. The navigation system 24 calculates a route to a set destination based on map information. The communication device 26 communicates with the outside of the vehicle using mobile communication. The information acquired from the outside by the communication device 26 includes weather forecast information. The illuminance sensor 28 measures the illuminance around the vehicle 2. The illuminance sensor 28 may be mounted on a camera for autonomous driving.

[0021] Vehicle 2 is equipped with a solar power generation manager 14. The solar power generation manager 14 is a computer that manages solar power generation using the solar cell 20. For example, the solar power generation manager 14 is configured by one or more ECUs. The solar power generation manager 14 is configured to acquire power generation state information from the solar cell 20 and battery information from the battery management system 22. Further, the solar power generation manager 14 has a function of acquiring route information to a destination from the navigation system 24, a function of acquiring weather forecast information and parking lot information using the communication device 26, and a function of acquiring illuminance information using the illuminance sensor 28.

[0022] When there is room in the state of charge (SOC) of the battery 12, the solar power generator 14 is programmed to increase the SOC of the battery 12 by charging with solar power. Specifically, the solar power generator 14 is programmed to search for a location where the amount of charging power of the battery 12 increases compared to the current location of the vehicle 2, and designate that location as the solar power generation point. The solar power generator 14 is further programmed to transmit the designated solar power generation point to the autonomous driving system 10 and instruct the autonomous driving system 10 to move the vehicle 2 to the solar power generation point.

[0023] By having the autonomous driving system 10 autonomously drive the vehicle 2 and move it to the solar power generation point, the amount of charging power from the solar battery 20 to the battery 12 can be increased compared to the case where it is not moved. However, the effect can be obtained only when the solar power generation point can be appropriately determined. Hereinafter, the battery charging method executed by the vehicle 2 will be described according to the method of determining the solar power generation point.

[0024] <The First Example> The first example is an example of moving the vehicle 2 by seeking a location where a higher power generation amount can be expected than the current location based on weather forecast information. For example, as shown in FIG. 2, assume that the weather forecast at the location (point A) where the vehicle 2 is parked at the previous day or in the morning of the current day was cloudy. In that case, even if the vehicle 2 continues to be parked at point A, the power generation amount by solar power generation hardly increases due to the lack of sunlight hitting the solar battery 20.

[0025] Therefore, the solar power generator 14 checks the weather at other locations based on the weather forecast information obtained by the communication device 26. The locations where the weather can be checked by the solar power generator 14 are parking lots where the vehicle 2 can be parked during the day. In the example shown in FIG. 2, there are four parking lots (points B, C, D, and E) at approximately equal distances from point A. According to the weather forecast, the future weather at point B will be cloudy, the future weather at point C will be sunny then cloudy, the future weather at point D will be sunny, and the future weather at point E will be sunny with occasional clouds. By using the weather forecast in this way, it is possible to find a location suitable for solar power generation at a distant location.

[0026] The solar power generator 14 determines point D, which has the best weather among the four neighboring points B, C, D, and E, as the new solar power generation point. Point D is the location where the strongest sunlight can be expected for the longest time among the four points B, C, D, and E. By setting the new solar power generation point, the automatic driving system 10 moves the vehicle 2 toward that solar power generation point. As a result, compared with the case of continuously parking the vehicle 2 at the local location, the amount of charging power of the battery 12 by solar power generation can be increased. As a result, the use of the power generated by sunlight in the vehicle 2 can be increased, and energy saving can be promoted.

[0027] Note that the weather forecast information used by the solar power generator 14 is preferably divided into as fine a mesh as possible. For example, weather forecast information divided into meshes at intervals of several kilometers, preferably intervals of 1 km or less, is used. It is also possible to use the information of the rain cloud radar as the weather forecast information. In that case, the solar power generator 14 moves the vehicle 2 to a location where rain clouds do not occur.

[0028] Also, when determining a new solar power generation point, it is searched whether there is space in the parking lot where the vehicle 2 will move. The solar power generation manager 14 examines the availability of the parking lot based on the parking lot information obtained by the communication device 26. The parking lot information may be provided by a dedicated parking lot search server, or may be provided by a vehicle management server that manages a group of autonomous vehicles including the vehicle 2. When the parking lot where the vehicle 2 will move is a paid parking lot, the solar power generation manager 14 calculates the amount of generated power that is expected to increase when the vehicle 2 moves to that parking lot compared to staying at the current location. If the amount obtained by converting the expected increased amount of generated power into an electricity charge exceeds the parking fee, the solar power generation manager 14 determines that parking lot as a new solar power generation point.

[0029] <Second example> The second example is an example in which, considering also the power consumption associated with movement, the vehicle 2 is moved to find a place where a higher amount of generated power can be expected than at the current location. The movement of the vehicle 2 is performed by the power stored in the battery 12. In the example shown in FIG. 3, it is assumed that the weather forecast at the place (point A) where the vehicle 2 is parked at the previous day or in the morning of the current day was cloudy.

[0030] The solar power generation manager 14 examines the weather at other places based on the weather forecast information obtained by the communication device 26. As a result of the investigation, it is found that the weather at point B is sunny with occasional clouds and the weather at point C is sunny all day. In this case, if the power consumption associated with movement is not considered, the solar power generation point to which the vehicle 2 should be moved is point C. However, there is a difference in the amount of power consumed by the vehicle 2 depending on the route from point A.

[0031] Here, let the expected power generation amount at point B be X1 kWh and the expected power generation amount at point C be X2 kWh. Also, let the expected power consumption amount during the movement from point A to point B be Y1 kWh and the expected power consumption amount during the movement from point A to point C be Y2 kWh. The power consumption amount is calculated based on the recent electricity bill and the distance on the map. Since the weather is better at point C, the power generation amount at point C is greater than the power generation amount at point B. That is, X2 > X1. However, since point C is farther from point A than point B, the power consumption amount to reach point C is greater than the power generation amount to reach point C. That is, Y2 > Y1.

[0032] Whether point C or point B is selected as the new solar power generation point is determined by the difference between the above-mentioned power generation amount and power consumption amount. As shown in Figure 3, when X2 - Y2 > X1 - Y1, point B is selected as the new solar power generation point. That is, even if the expected power generation amount from the weather forecast is relatively small, if the power consumption amount until moving to that location is also relatively small, a location other than the place with the best weather may be determined as the solar power generation point.

[0033] However, depending on the distances of point B and point C from point A, the power consumption amount may exceed the power generation amount at both point B and point C. In that case, there is no merit in moving vehicle 2. Therefore, when there is no place where the expected power generation amount can exceed the power consumption amount, the solar power generation manager 14 maintains the solar power generation point at point A. By including the power consumption amount required for movement in the calculation, it is possible to determine whether there is a merit in moving vehicle 2 only by solar power generation.

[0034] <The Third Example> The third example is an example in which the vehicle 2 is moved to find a sunny place in the parking lot. As shown in FIG. 4A, when the vehicle enters the parking lot, the solar power generation manager 14 selects a parking space that is not in the shade of other objects and parks the vehicle 2. Which parking space has good sunlight can be determined based on the illuminance information obtained from the illuminance sensor 28. The selected parking space is set as the initial position of the solar power generation point.

[0035] However, the situation in which the vehicle 2 is placed changes from the time when the vehicle 2 is parked, and the state of good sunlight does not necessarily continue. For example, as shown in FIG. 4B, a large truck 4 may be parked in the parking space adjacent to the vehicle 2. Since the large truck 4 has a higher vehicle height than the vehicle 2, depending on the direction of the sun, the vehicle 2 may enter the shade 40 created by the large truck 4. When the vehicle 2 enters the shade 40 and sunlight does not reach the solar cell 20, the generated voltage by solar power generation decreases.

[0036] The solar power generation manager 14 recognizes that the vehicle 2 has entered the shade 40 from the power generation state information obtained from the solar cell 20. For example, when the generated voltage drops rapidly and that state continues for a certain period of time, it can be determined that the vehicle 2 has entered the shade of some object. The generated voltage of the solar cell 20 also drops when the sun is temporarily hidden by clouds. However, whether the drop in the generated voltage is due to the temporary effect of clouds or due to the vehicle 2 being hidden in the shade of an object can be determined from the manner of change in the generated voltage. Also, whether the vehicle 2 has entered the shade 40 can be determined from the illuminance information obtained from the illuminance sensor 28.

[0037] When the vehicle 2 enters the shade 40 and the generated voltage of the solar cell 20 decreases, the solar power generation manager 14 searches for a new solar power generation point. The new solar power generation point is the place with the shortest moving distance from the current location among the places where sunlight can be applied to the solar cell 20. The places where sunlight can be applied to the solar cell 20 can be determined based on the illuminance information obtained from the illuminance sensor 28. The reason for selecting the place with the shortest moving distance is to minimize the energy consumption for movement.

[0038] In the example shown in FIG. 4C, since the parking space adjacent to the current parking space is vacant, the solar power generation manager 14 determines that parking space as the new solar power generation point. By setting the new solar power generation point, the automatic driving system 10 moves the vehicle 2 toward that solar power generation point. As a result, sunlight can be continuously applied to the solar cell 20, and the amount of power charged to the battery 12 by solar power generation can be increased. As a result, the utilization of the power generated by sunlight in the vehicle 2 can be increased, and energy saving can be promoted.

[0039] <Fourth Example> The fourth example is an example of determining the place to move the vehicle 2 based on the illuminance database 50 in which the illuminance data for each time and each place is accumulated. An image of the illuminance database 50 is shown in FIG. 5. In FIG. 5, the dark-colored squares indicate places with low illuminance, and the light-colored squares indicate places with high illuminance. In the example shown in FIG. 5, the illuminance data at 8 o'clock, 11 o'clock, 14 o'clock, and 17 o'clock at 20 pre-registered places are accumulated in the illuminance database 50.

[0040] The illuminance data may be data obtained by illuminance sensors installed at various locations, or may be data obtained by an illuminance sensor provided in the vehicle. The illuminance database 50 is built in a vehicle management server that manages a plurality of autonomous vehicles. Each autonomous vehicle transmits the illuminance data obtained by the illuminance sensor together with the position information and time acquired by GPS to the vehicle management server. The vehicle management server accumulates the illuminance data sent from each autonomous vehicle in the illuminance database 50.

[0041] The solar power generator manager 14 accesses the illuminance database 50 at a predetermined time interval. Then, based on the illuminance data at a future time compared to the current time, it determines whether the vehicle 2 should be moved, and if so, which location should be determined as a new solar power generation point. Specifically, if the illuminance data indicates that the illuminance at the current location will decrease at the next registration time, the solar power generator manager 14 determines the location closest to the current location among the locations where the illuminance is maintained as the new solar power generation point. In this way, by using the illuminance database 50 in which past performance has been accumulated, it is possible to predict a location suitable for solar power generation and move the vehicle 2.

[0042] <The Fifth Example> The fifth example is an example of determining the location to move the vehicle 2 based on the 3D map data and the date and time. FIG. 6 shows images of the 3D map data 60 and the sun model 62. The 3D map data 60 includes data on terrain and building heights. The sun model 62 is a model that associates the date and time with the position of the sun. By combining the 3D map data 60 with the sun model 62 in a simulation, it is possible to determine which places are in the shade and which are not in the shade in the plan view.

[0043] The solar power generation manager 14 may perform a simulation on its own using the 3D map data 60 and the solar model 62, or may receive the result of the simulation performed by the vehicle management server. The solar power generation manager 14 identifies a parking lot where the vehicle 2 can be parked and is not in the shade, and determines a solar power generation point from among the parking lots that are not in the shade. Since the size of the building can be known from the 3D map data 60 and the position of the sun can be known from the solar model 62, it is possible to accurately predict a location that is not in the shade and suitable for solar power generation and move the vehicle 2.

[0044] <Modification Example> Considering the power consumption associated with movement described in the second example, finding a location where a higher power generation amount can be expected than the current location and moving the vehicle 2 can also be applied to the third, fourth, and fifth examples. Also, moving the vehicle 2 only when it is worth moving considering the parking fee described in the first example can also be applied to the second, third, fourth, and fifth examples.

[0045] The process of determining the solar power generation point where the vehicle 2 should be parked may be performed by the vehicle management server. That is, the function provided by the solar power generation manager 14 provided in the vehicle 2 in the above-described embodiment may be transferred to the vehicle management server connected to the vehicle 2 via a network, and the vehicle 2 may move according to an instruction from the vehicle management server. Also, when the vehicle 2 is connected to the user's terminal, the user's terminal may instruct the vehicle 2 to a solar power generation point where the vehicle 2 should be parked.

[0046] When moving the vehicle 2 to the solar power generation point, it may be possible to move the vehicle 2 to the solar power generation point after passing it through an automatic car wash. By passing the vehicle 2 through the automatic car wash, it is possible to remove dirt from the panels of the solar cell 20 and lower the temperature of the solar cell 20. As a result, the vehicle 2 can be directed towards the solar power generation point with the power generation efficiency of the solar cell 20 enhanced. Also, a wiper for wiping the panels of the solar cell 20 may be provided on the vehicle 2, and the panels of the solar cell 20 may be wiped with the wiper before the vehicle 2 moves to the solar power generation point. Since the roof of the vehicle 2 is likely to get dirty, an effect of improving the power generation efficiency of the solar cell 20 can be expected even by simply wiping the panels with the wiper.

Explanation of Signs

[0047] 2 Autonomous vehicle 4 Large truck 10 Autonomous driving system 12 Battery 14 Solar power generation manager 20 Solar cell 22 Battery management system 24 Navigation system 26 Communication device 28 Illuminance sensor 40 Shade 50 Illuminance database 60 3D map data 62 Solar model

Claims

1. In an autonomous vehicle equipped with a solar cell and a battery that can be charged with the power generated by the solar cell, searching for a solar power generation point where the amount of charge of the battery increases compared to the current location; calculating the amount of power generation that is expected to increase when moving to the solar power generation point compared to staying at the current location; calculating the amount of power consumption predicted for the movement to the solar power generation point; calculating the differential power amount between the expected increased power generation amount and the predicted power consumption amount; when the solar power generation point is a paid parking lot, moving automatically to the solar power generation point on the condition that the amount obtained by converting the differential power amount into an electricity charge exceeds the parking fee. An autonomous vehicle characterized by the above.

2. In the autonomous vehicle according to Claim 1, determining the solar power generation point based on the weather forecast of the surrounding area. An autonomous vehicle characterized by the above.

3. In the autonomous vehicle according to Claim 1, determining, as the solar power generation point, a location where the illuminance detected by an illuminance sensor is higher than the surroundings. An autonomous vehicle characterized by the above.

4. In the autonomous vehicle according to Claim 1, determining the solar power generation point based on an illuminance database in which illuminance data for each time and each location is accumulated. An autonomous vehicle characterized by the above.

5. In the autonomous vehicle according to Claim 1, identifying a non-shaded location based on 3D map data and time, and determining the solar power generation point from among the non-shaded locations, and being configured to execute the above An autonomous vehicle characterized by the above.

6. A method for charging a battery of an autonomous vehicle equipped with a solar cell, comprising: searching for a solar power generation point where the amount of charge of the battery increases compared to the current location of the autonomous vehicle; calculating the expected power generation amount that is expected to increase when moving to the solar power generation point compared to staying at the current location; calculating the expected power consumption amount predicted by moving to the solar power generation point; calculating the differential power amount between the expected power generation amount that is expected to increase and the expected power consumption amount; when the solar power generation point is a paid parking lot, moving the autonomous vehicle to the solar power generation point by autonomous driving on the condition that the amount obtained by converting the differential power amount into an electricity charge exceeds the parking fee; A charging method characterized by the above.

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