JP7609142B2 - Solar-powered vehicle - Google Patents

Description

The present invention relates to a vehicle equipped with solar cells, and more specifically, to a vehicle in which solar cells are arranged on the windows.

Attempts have been made to mount solar cells on the top surface of a vehicle such as an automobile, generate electricity in the vehicle, and use the energy for various operations in the vehicle (for example, Patent Documents 1 and 2). In this regard, since general solar cells (such as Patent Document 3) do not transmit light, such solar cells cannot be placed, for example, in transparent windows for lighting in a vehicle (windows through which passengers can see outside the vehicle from inside the vehicle, or windows for lighting the interior of the vehicle). However, in recent years, transparent solar cells (such as Patent Documents 2, 4, and 5) that transmit light with wavelengths in the visible light range and generate electricity using ultraviolet or near-infrared light have been developed and proposed for use, and such transparent solar cells can be used as windows that can generate electricity while also receiving light by being fitted into or installed on the window in a vehicle. Patent Document 6 proposes a configuration in which a liquid crystal panel whose transparency changes depending on the current state is placed on the light-receiving surface side of the solar cell in order to prevent electric shocks and the like in the event of a disaster, and the liquid crystal panel is controlled to become opaque in the event of a power outage, thereby stopping the power generation of the solar cell device.

Patent Publication 2009-10127 International Publication No. 2007/013389 Patent Publication No. 2021-168322 Patent Publication No. 2018-32872 Patent Publication No. 2018-29048 JP 8-316513 A

In the above-mentioned configuration in which a transparent solar cell that transmits visible light (hereinafter referred to as a "transparent solar cell") is placed on a vehicle window, the transparent solar cell transmits visible light, so the energy of visible light is not used to generate electricity. As a result, the efficiency of using solar energy is lower than that of a solar cell that generates electricity using light over a wide range of wavelengths of sunlight.

The need for each vehicle window (front window, side window, rear window, skylight (sunroof, panoramic roof)) to admit visible light varies depending on the driving or usage conditions of the vehicle, or on the location of the window. For example, if there are no occupants in the vehicle, there is no need for lighting from all windows in the vehicle. Also, if the vehicle is not being driven, there is less need for lighting from the front window, side windows, and rear window so that occupants can see outside the vehicle from inside the vehicle. Alternatively, if it is desired to reduce the amount of sunlight entering the vehicle cabin (e.g., when the sunlight is too strong), there is no need for lighting from skylights to illuminate the interior of the vehicle. Also, if only lighting necessary for the vehicle to travel is required, there is no need for lighting from window areas that are not necessary for occupants to see the situation outside the vehicle, such as skylights and parts of the side windows. In situations where lighting through such windows is unnecessary or less necessary, there is no need to transmit visible light into the vehicle interior through windows that do not require lighting, so it would be advantageous only in such situations if windows that do not require lighting could use not only the ultraviolet or near-infrared light in the sunlight irradiated onto them, but also visible light for power generation. In other words, if the state of each of the vehicle's windows could be switched so that power could be generated using visible light depending on the vehicle's driving or usage conditions, it would be possible to improve the efficiency of solar energy utilization.

Thus, the objective of the present invention is to improve the efficiency of solar energy usage in vehicles with windows by enabling power generation using visible light for each window depending on the vehicle's usage conditions.

According to one aspect of the present invention, the above object is achieved by providing a vehicle having a window, the vehicle comprising:
a usage status detection means for detecting a usage status of the vehicle;
This is achieved by a vehicle that includes a window photovoltaic power generation state switching means that selects from the windows those that do not let in visible light based on the detected usage status, and switches the selected window from a transparent state that lets in visible light to a state in which photovoltaic power generation is possible using visible light.

In the above configuration, the "window" of the vehicle refers to the area within the window frame opened in the outer wall that defines the passenger compartment, and may specifically refer to the front window, side window (door window), or rear window. In addition, in the case of a vehicle having a skylight such as a sunroof or panoramic roof, the skylight may also be included. The "vehicle usage status" to be detected is the specific situation in which the vehicle is being used, such as whether the vehicle is being used or not, whether the vehicle is being driven or not, as will be explained in more detail later, and may in particular be the vehicle usage status related to the need for light from each window, the remaining charge of the on-board battery, the driving mode (eco mode, normal mode, sports mode, etc.), and the degree of need for electric energy in the vehicle or the need for power generation. The "usage status detection means" may be a sensor capable of detecting the above-mentioned vehicle usage status. As described above, the "window photovoltaic power generation state switching means" selects a window from among the vehicle windows that does not let in visible light based on the detected usage status, and switches the state of the selected window from a transparent state that lets in visible light to a state in which photovoltaic power generation is possible using visible light by any method. Note that the "transparent state that lets in visible light" refers to a state in which the state of one side of the window can be seen from the other side with the naked eye.

According to the above configuration, in a vehicle having windows, the usage status of the vehicle is detected, and based on the detected usage status, windows that do not require the collection of visible light or windows that do not require the collection of visible light are selected as windows that do not collect visible light, and photovoltaic power generation using visible light is performed in the selected windows. This increases the opportunities for photovoltaic power generation using visible light, thereby improving the efficiency of solar energy utilization.

In the above-described configuration of the present invention, various vehicle usage conditions are detected in order to select a window that does not let in visible light, and a window that does not let in visible light may be selected in accordance with the detected usage conditions, as described below.
(1) The vehicle usage status may be that the vehicle is not in use, specifically, that no occupants are in the vehicle (for example, determined from the detection state of a weight detection sensor for a seat belt reminder on each seat and a radio wave sensor for detecting a riding position to prevent an infant from being left behind), or that the drive device of the vehicle is not activated (for example, determined from the state of an ignition switch and a ready switch). In this case, all windows may be selected as windows that do not let in visible light.
(2) As the vehicle usage status, it may be detected whether the vehicle is being driven, specifically, whether the shift lever is in the P range, and whether the vehicle is stopped (the vehicle speed is 0 km for reasons other than waiting at a traffic light or stopping). When it is detected that the vehicle is being driven, the windows (front window, rear window, and some side windows) used by the occupants to see outside the vehicle may not be selected as windows that do not let in visible light (i.e., they are switched to a transparent state in which photovoltaic power generation using visible light is not performed). On the other hand, when it is detected that the vehicle is not being driven, the windows used by the occupants to see outside the vehicle may be selected as windows that do not let in visible light.
(3) As the usage status of the vehicle, the remaining charge of the vehicle battery or the driving mode (such as a mode that prioritizes driving performance or a mode that prioritizes fuel efficiency) may be detected. In this case, when the remaining charge of the vehicle battery is low (below a predetermined amount that is arbitrarily set) or when an energy saving mode is selected, windows that are not used for passengers to see outside the vehicle (such as skylights and some side windows) may be selected as windows that do not let in visible light.

In an embodiment, the above configurations (1), (2), and (3) may be combined. For example, a configuration may be used in which a candidate window that does not admit visible light is selected according to the remaining charge of the vehicle battery or further according to the mounting position of the vehicle, and further, the candidate window that does not admit visible light is narrowed down according to the driving mode, and a window that does not admit visible light is actually determined from the candidate window that does not admit visible light according to whether the vehicle is in operation or not. In addition, whether or not the occupant requests daylighting as the vehicle usage status may be determined from the state of a button or switch operated by the occupant, and a window that the occupant does not request daylighting may be selected as a window that does not admit visible light. Furthermore, the seating position of the occupant and the direction of the driver's line of sight may be detected as the vehicle usage status, and a window that does not admit visible light may be selected according to each individual situation.

Other vehicle conditions may be detected as usage conditions, and depending on the usage conditions, windows that do not require the introduction of visible light or that do not introduce visible light may be selected as appropriate, and such cases also fall within the scope of the present invention.

In the configuration of the present invention, as described above, a window that does not receive visible light can be switched from a transparent state that receives visible light to a state in which visible light is used to generate electricity. For example, in one embodiment, the state in which visible light is used to generate electricity can be achieved by arranging solar cells (hereinafter referred to as "visible light solar cells") along the window that do not transmit visible light and that absorb visible light to generate electricity. Also, each window of the vehicle may be equipped with a transparent "transparent solar cell" that generates electricity using near-infrared light in sunlight. In that case, the state in which visible light is also used to generate electricity can be achieved by arranging an interior panel or curtain such as a shade along the window that is laminated with a layer that converts visible light into near-infrared light using a substance that absorbs visible light and emits near-infrared light, and a reflective layer that returns the near-infrared light obtained from visible light to the transparent solar cell installed in the window.

More specifically, the arrangement of visible light power generation means (means for generating power using visible light), such as visible light solar cells, can be achieved, for example, as follows:

(i) For each window, a visible light solar cell is placed next to a movable, retractable shade that can be placed along the interior side of the window to provide sun protection, and when switching to a state in which photovoltaic power generation using visible light is possible, the shade is placed along the interior side of the window. When the shade is placed along the window, visible light that passes through the window is incident on the visible light solar cell, making it possible to generate power using visible light.

(ii) When a transparent solar cell that generates electricity using near-infrared light is installed in each window, a reflective layer that reflects light and a wavelength conversion layer that converts visible light to near-infrared light are laminated in that order on the side of the shade on each window facing the window as described above, and when switching to a state in which photovoltaic power generation using visible light is possible, the shade is placed along the surface of the window facing the interior of the vehicle. When the shade is placed along the window, visible light that passes through the window is converted to near-infrared light by the wavelength conversion layer, and then reaches the transparent solar cell in the window, either directly or after being reflected by the reflective layer, where it is absorbed, generating electricity.

(iii) In each window, multiple rectangular plate members on which visible light solar cells are arranged are rotatably arranged side by side so that they extend along the surface direction of the window. In this configuration, in each window, when visible light is collected, the orientation of each plate is rotated so that the surface direction of the multiple rectangular plate members is aligned with the direction of light incidence at the window, thereby allowing light that has passed through the window to reach the interior of the vehicle. On the other hand, when visible light is not collected, the orientation of each plate is rotated so that the surface direction of the multiple rectangular plate members is aligned with the surface direction of the window, thereby allowing visible light that has passed through the window to be incident on the visible light solar cells of the multiple rectangular plate members, thereby generating electricity.

(iv) When a transparent solar cell that generates electricity using near-infrared light is installed in each window, a plurality of strip-shaped plate members, each of which is made up of a reflective layer that reflects light and a wavelength conversion layer that converts visible light to near-infrared light, are rotatably arranged in parallel on each window so that they extend along the surface direction of the window. As described above, when visible light is collected, the orientation of each strip-shaped plate member is rotated so that the surface direction of the strip-shaped plate members is aligned with the direction of light incidence, thereby allowing light that has passed through the window to reach the interior of the vehicle. On the other hand, when visible light is not collected, the orientation of each strip-shaped plate member is rotated so that the surface direction of the strip-shaped plate members is aligned with the surface direction of the window, thereby allowing visible light that has passed through the window to be converted into near-infrared light in the strip-shaped plate members, which then enters the transparent solar cell of the window directly or after being reflected by the reflective layer, thereby generating electricity.

In any other manner, a visible light power generation means may be placed in a window selected as a window that does not let in visible light, and visible light may be used to generate electricity, and such cases also fall within the scope of the present invention.

As already mentioned, in the vehicle of the present embodiment described above, each window may be equipped with a transparent solar cell that generates electricity by absorbing light in wavelength ranges other than the visible light range. In this case, if sunlight is irradiated onto the vehicle, electricity can be generated at all times in each window using ultraviolet or near-infrared light in the sunlight, regardless of whether visible light is being collected or not.

Thus, in the present invention described above, a window that does not capture visible light is selected from among the multiple windows in the vehicle depending on the individual usage conditions of the vehicle, and in such a selected window, power generation can be performed not only by transparent solar cells using ultraviolet or near-infrared light in sunlight, but also by using visible light in sunlight. With this configuration, it is possible to increase the opportunities for power generation using visible light while ensuring the capture of visible light necessary for the use and operation of the vehicle, thereby improving the efficiency of solar energy utilization. The configuration of the present invention may be applied to various vehicles.

Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention.

Fig. 1(A) is a schematic side view of a vehicle to which the present embodiment is applied, and Fig. 1(B) is a block diagram showing the configuration of a control system for selecting a window for generating power using visible light according to the present embodiment. 2A and 2B are schematic diagrams showing a window according to this embodiment and an example of a configuration for generating power using visible light by using a sliding shade on the window, respectively. 3A to 3D are schematic diagrams showing an example of a configuration for generating power using visible light, comprising a plurality of rectangular flat plates on a window according to this embodiment, in which (A) and (C) are perspective and cross-sectional views of a state in which visible light is introduced into the vehicle interior (transparent state), and (B) and (D) are perspective and cross-sectional views of a state in which visible light is blocked from entering the vehicle interior (non-transparent state). FIG. 4 is a flowchart showing a process for determining the visible light transmission state (transparent state/non-transparent state) of a vehicle skylight and rear side window (a window not used for the driver to see outside the vehicle) according to this embodiment. FIG. 5 is a diagram illustrating, in the form of a flow chart, a process for determining the transparent/non-transparent state of a window depending on the driving conditions of the vehicle according to this embodiment.

1...vehicle, 1a...exterior wall, 1w...window frame, 2f...front window, 2r...rear window, 2pf, 2pr...front and rear skylights, 2sf, 2sr...front and rear side windows, 2a...transparent solar cell, 3...shade, 4...interior material, 5...visible light solar cell, 5a...hinge shaft, 6...shade drive device, 7...reflective layer, 8...wavelength conversion layer, 11...start switch (ready switch, ignition switch), 12FL,FR,RL,RC,RR...occupant detection sensors for each seat (seat weight detection sensor, radio wave sensor), 13...shift lever - Position sensor, 14FL,FR,RL,RC,RR... Seat belt sensors for each seat, 15... Vehicle speed sensor (wheel speed sensor), 16... GPS/navigation system, 17... Window lighting selection switch, 17a... Accelerator pedal sensor, 17b... Brake pedal sensor, 18... Driving mode switch, 19... Driver's line of sight sensor, 20... Battery remaining capacity sensor, 21... Transparent solar cell power generation detection sensor, 50... Selection processing device, 60f-pr... Window state switching means (actuator), vl... Visible light, irl... Near infrared, S... Sun

Vehicle configuration and overview of this embodiment With reference to FIG. 1(A), this embodiment is applied to each window (front window 2f, rear window 2r, left and right front side windows 2sf, left and right rear side windows 2sr) in a vehicle 1 such as an automobile as shown in the figure. In addition, in the case where a skylight called a panoramic roof, a sunroof, or the like is formed in the vehicle 1, this embodiment may be applied to the skylight 2pf, pr (front, rear). As described later, each of these windows is provided with a transparent solar cell (transparent solar cell) that transmits visible light and generates electricity using ultraviolet light or near infrared light, and when sunlight is irradiated on the vehicle 1, photovoltaic power generation by the transparent solar cell may be performed at all times. In each window, the transparent solar cell may be embedded in a flat plate made of a transparent glass material or resin material in the window frame, or may be attached to the flat plate.

In the above-mentioned configuration in which transparent solar cells are installed in each window, it is possible to let light into the vehicle interior while generating electricity, but since transparent solar cells do not use visible light, which accounts for a large proportion of sunlight, for generating electricity, the efficiency of using solar energy is reduced compared to solar cells that generate electricity using light over a wide range of wavelengths in sunlight. In this regard, as described in the "Summary of the Invention", it is not always necessary to let light in through each window, and depending on the usage conditions of the vehicle, the need for lighting through each window may disappear or become less necessary. Therefore, in this embodiment, a window that does not let visible light in is selected depending on the usage conditions of the vehicle, and the selected window is switched from a transparent state that lets in visible light to a state in which photovoltaic power generation is possible using visible light. This increases the opportunities to generate electricity using visible light, and improves the efficiency of using solar energy. Note that this embodiment may be applied to a vehicle in which transparent solar cells are not installed in each window, and such a case also falls within the scope of this embodiment.

In this embodiment, the selection of windows that do not let in visible light in accordance with the vehicle usage status and the switching to a state in which photovoltaic power generation using visible light is possible through the operation of a selection processing device 50 that executes the process of selecting windows that do not let in visible light using information obtained from a group of sensors (usage status detection means) 11-21 that detects various vehicle usage statuses, and actuators 60f-pr that switch the state of the visible light power generation means (visible light solar cells, etc.) (window photovoltaic power generation state switching means) as shown in Fig. 1(B). The selection processing device 50 may be realized by an operation according to a program by a computer device.

With reference to the figure, in the control system, detection outputs from the following sensor group may be input to the selection processing device 50 as information representing the usage status of the vehicle. (1) Start switch 11 - may be a switch for starting the vehicle, such as a ready switch or an ignition switch. (2) Each seat occupant detection sensor 12 FL, FR, RL, RC, RR - may be a sensor that can detect the presence or absence of an occupant in each seat FL, FR, RL, RC, RR, such as a seat weight detection sensor or a radio wave sensor. (3) Shift lever position sensor 13 - a sensor that detects the position of the shift lever. (4) Each seat seat belt sensor 14 FL, FR, RL, RC, RR - may be a sensor that detects the fastening status of the seat belt of the seat in which the occupant is seated. (5) Vehicle speed sensor 15 - a sensor that calculates the vehicle speed from the detection value of a wheel speed sensor or the like. (6) GPS/navigation system 16 - may be a system that can detect the position of traffic lights and stop signs. (7) Window lighting selection switch 17 - A switch operated by the occupant to determine whether or not lighting (visible light) is required for each window. (8) Driving mode switch 18 - A switch to select ECO mode, NORMAL mode, or SPORTS mode. (9) Driver's line of sight sensor 19 - A sensor that detects the driver's line of sight. (10) Battery remaining capacity sensor 20 - A sensor that detects the remaining capacity of the vehicle battery. (11) Transparent solar cell power generation detection sensor 21 - A sensor that detects the amount of power generated by transparent solar cells installed in each window. (12) Accelerator pedal sensor 17a, brake pedal sensor 17b - Sensors that detect the depression of the accelerator pedal or brake pedal.

The selection processing device 50 uses information from the above-mentioned sensor group to select windows that do not let in visible light in a manner described later, and sends out control commands to operate actuators 60f-pr that switch the state of each window. When a window is selected as one that does not let in visible light, the actuators 60f-pr operate in one of the manners described later to position the visible light power generation means in a position where visible light from the window is irradiated, and when a window is not selected as one that does not let in visible light, they operate to store the visible light power generation means so that visible light can reach the vehicle interior from the window.

Configuration and operation for switching each window between transparent and non-transparent states Any method may be adopted for the configuration for switching each window between a state in which visible light is let in (transparent state) and a state in which visible light can be used to generate electricity (non-transparent state--a state in which visible light is not let in).

For example, in one embodiment, as shown in FIG. 2(A), a movable shade 3 that can be arranged to cover the window 2 is installed along an area (window) 2 within a window frame 1w opened in the outer wall 1a of the vehicle, and a visible light solar cell 5 is installed on the window 2 side of the interior material 4 of the shade 3 as a visible light power generation means. The shade 3 is configured to be slidable in the direction of arrow X by an actuator 6 (60f-pr), or, although not shown, may be configured to be pivotable relative to the window 2 in a hinged manner. As described above, the window 2 may be equipped with a transparent solar cell 2a so that it can generate power using ultraviolet light or near-infrared light irl in sunlight S. In this configuration, when the window 2 is selected as a window that collects visible light (transparent state), the shade 3 is retracted toward the outer wall 1a and stored, and visible light vl from the window 2 reaches the interior 1b of the vehicle. On the other hand, when the window 2 is selected as a window that does not let in visible light (non-transparent state), the shade 3 is positioned to extend to a position that covers the window 2, and the visible light vl in the sunlight S from the window 2 is incident on the visible light solar cell 5, and power generation is performed using the visible light vl.

In the above-mentioned configuration using the shade 3, when a transparent solar cell 2a that generates electricity using near-infrared light irl is installed on the window 2, a reflective layer 7 that reflects near-infrared light and a wavelength conversion layer 8 that converts visible light to near-infrared light may be laminated in this order on the shade 3 as a visible light power generation means instead of the visible light solar cell 5. The wavelength conversion layer 8 may be, for example, a layer in which a fluorescent material or phosphorescent material that absorbs visible light and emits near-infrared light is dispersed in a resin or glass. According to this configuration, when the shade 3 is arranged so as to extend to a position covering the window 2, the visible light vl from the window 2 is incident on the wavelength conversion layer 8, where it is converted into near-infrared light irl and incident on the transparent solar cell 2a, so that power generation using visible light vl is achieved.

As another embodiment for making each window capable of generating electricity using visible light, as shown in Figs. 3(A) to (D), a configuration may be used in which flat plates 10 carrying multiple rectangular visible light solar cells (or a laminate of a wavelength conversion layer and a reflective layer) are arranged in parallel along the window 2 on the interior side I of the window 2 as a visible light power generation means. In this case, transparent solar cells 2a may also be installed on the window 2. In such a configuration, each flat plate 10 may be configured to be pivotable around a pivot 10a. Then, when the window 2 is selected as a window that collects visible light (transparent state), as shown in Figs. 3(A) and (C), each flat plate 10 is arranged in a direction extending along the traveling direction of visible light vl transmitted through the window 2, so that the visible light vl reaches the interior I of the vehicle. On the other hand, when the window 2 is selected as a window that does not receive visible light (non-transparent state), each flat plate 10 is pivoted in a direction extending along the surface direction of the window 2 to cover the window 2, whereby visible light vl is incident on the visible light solar cell (or a laminate of a wavelength conversion layer and a reflective layer) on the flat plate 10, and power generation is achieved using the visible light vl, as in the case of FIG. 2. The angle of the rectangular flat plate 10 may be adjusted appropriately so that the occupants are not dazzled.

Selection process for windows that do not admit visible light (windows that generate power using visible light) As already described, in this embodiment, windows that do not admit visible light are selected as windows that generate power using visible light based on various usage conditions of the vehicle. In this selection process, basically, when the vehicle is not being used or driven, as many windows as possible may be switched to a state in which they can generate power using visible light. Also, when the level of power generation demand is high, such as when the battery level is low or when an eco mode (a mode that prioritizes fuel efficiency) is selected, as many windows as possible may be switched to a state in which they can generate power using visible light. Below, several aspects of the selection process for windows that do not admit visible light will be described.

(i) Control of Skylights and Rear Side Windows Rear side windows and skylights (if installed) are windows other than those used by occupants to see outside the vehicle while driving, so whether or not to let in visible light may be selected depending on whether the vehicle is in use, the seating positions of the occupants, the level of power generation demand, etc.

As one embodiment, for example, referring to FIG. 4, when the start switch is OFF (step 1), when the remaining battery charge is insufficient (when it is less than a predetermined value Co) (step 2), when the eco mode is selected (step 3), or when there is no occupant (step 4 - detected by each seat occupant detection sensor 12), the left and right rear side windows srl, srr and the front and rear skylights pf, pr may all be selected to a non-transparent state (windows that do not let in visible light) (step 5). On the other hand, if the start switch is ON, the battery level is sufficient, a mode other than eco mode is selected, and there is a passenger in the rear seat, the left and right rear side windows srl, srr, and the rear skylight pr are made transparent (steps 6, 7), if there is no passenger in the rear seat, the left and right rear side windows srl, srr, and the rear skylight pr are made non-transparent (steps 6, 8), if there is a passenger in the front seat (driver's seat, passenger seat), the front skylight pf is made transparent (steps 9, 10), and if there is no passenger in the front seat, the front skylight pf may be made non-transparent (steps 9, 11). As a result, visible light is introduced to the seats where passengers are present, and power generation using visible light is performed in the windows for introducing light to the seats where no passengers are present.

Pf: 天窓前方、Pr: 天窓後方、Srl、Srr左右後方サイドウィンドウ
Ｃｏ、Ｃ１（＞Ｃｏ）は、適宜設定される所定値。
即ち、バッテリ残量が少ないほど、或いは、運転モードで燃費を重視する度合が高いほど、多くの窓が可視光の採光をしない窓として選択され、可視光を用いた発電が実行される。 In another embodiment, whether or not the rear side windows and the skylight let in visible light may be selected in various combinations depending on the remaining battery charge and the selected driving mode. Specifically, as shown in Table 1 below, windows that do not let in visible light may be selected.

Pf: front of the skylight, Pr: rear of the skylight, Srl, Srr: left and right rear side windows Co, C1 (>Co) is a predetermined value that is appropriately set.
That is, the lower the remaining battery charge, or the higher the degree to which fuel efficiency is emphasized in the driving mode, the more windows are selected as windows that do not let in visible light, and power generation using visible light is executed.

ｗｏ、ｗ１（＞ｗｏ）は、適宜設定される所定値。 Furthermore, in cases where transparent solar cells are installed in the windows, whether or not the rear side window and skylight will collect visible light may be selected in various combinations depending on the power generation output W of the transparent solar cells. The greater the power generation output W of the transparent solar cell, the stronger the sunlight intensity will be, so more windows may be selected as windows that do not collect visible light, and power generation using visible light may be performed. Specifically, windows that do not collect visible light may be selected, as shown in Table 2 below.

wo, w1 (>wo) are predetermined values that are appropriately set.

(ii) Control of the Front, Rear, and Front Side Windows The front window, rear window, and front side windows are windows used by occupants to see outside the vehicle while driving, so whether or not to let in visible light may be selected depending on whether or not the vehicle is in use and whether or not the vehicle is being driven or traveling.

Specifically, referring to FIG. 5, first, if the start switch is OFF (step 21), the driver is not present (step 22), the seat belt is not fastened (step 23), or the shift lever is in the P range (step 24), the vehicle will not start, so the front window, rear window, and front side windows are all selected to be non-transparent, and power generation using visible light may be performed (step 25). On the other hand, if the start switch is ON, the driver is seated, the seat belt is fastened, and the shift lever is not in the P range, the vehicle is in a state where it can start, so in this case, the state of the above windows is selected depending on whether the vehicle is being driven or traveling.

More specifically, first, when the vehicle speed is 0 km/h at the time of starting (step 26), if the accelerator pedal or brake pedal is depressed (step 27), the above-mentioned window is set to a transparent state (step 28). Then, when the vehicle speed is higher than 0 km/h, the vehicle is moving, so the above-mentioned window is maintained in a transparent state (steps 26, 28). After that, even when the vehicle stops, if the pedal is depressed or the stop is due to waiting at a traffic light or temporary stop (which may be detected by a navigation system, etc. - step 29), the above-mentioned window is maintained in a transparent state. On the other hand, when the vehicle is stopped, the pedal is not depressed, the stop is not due to waiting at a traffic light or temporary stop, and the state has passed for a predetermined time that may be set arbitrarily, it is determined that the vehicle has finished traveling, the above-mentioned window is selected to be in a non-transparent state (step 25), and power generation using visible light may be performed. Furthermore, if the pedal is depressed thereafter, the above-mentioned window is switched to a transparent state (step 28). The state of the rear side windows and skylights may also be switched by the process shown in Figure 5.

(iii) Selection by Occupant The windows that do not let in visible light may be selected by the occupant by operating the light-admitting selection switch 17 of each window. The selected window is made non-transparent.

(iv) Selection Based on Driver's Line of Sight While the vehicle is being driven, the driver's line of sight may be detected by the driver's line of sight sensor 19, and the window in the direction of the driver's line of sight may be made transparent, while the other windows may be made non-transparent.

For windows that have been selected to be non-transparent through the above series of selection processes, the visible light power generation means is placed along the window, as described in relation to Figures 2 and 3, and photovoltaic power generation using visible light is carried out. With this configuration, as already mentioned, there are more opportunities to generate power using visible light, improving the efficiency of solar energy utilization.

The above description is given in relation to an embodiment of the present invention, but many modifications and changes are easily possible for those skilled in the art, and it is clear that the present invention is not limited to the embodiment exemplified above, but can be applied to various devices without departing from the concept of the present invention.

Claims (5)

A vehicle having a window,
a usage status detection means for detecting a usage status of the vehicle;
and a window photovoltaic power generation state switching means for selecting from the windows a window that does not let in visible light based on the detected usage status, and switching the selected window from a transparent state that lets in visible light to a state in which photovoltaic power generation is possible using visible light. A vehicle according to claim 1, wherein the usage detection means is configured to detect whether the vehicle is in use as the usage state of the vehicle, and the window photovoltaic power generation state switching means is configured to switch all of the windows to a state in which photovoltaic power generation by visible light is possible when it is detected that the vehicle is not in use. A vehicle according to claim 1, wherein the usage detection means is configured to detect whether the vehicle is being driven as the usage state of the vehicle, and the window photovoltaic power generation state switching means is configured to switch the window used by the occupants to view the outside of the vehicle to a transparent state in which photovoltaic power generation using visible light is not performed when it is detected that the vehicle is being driven, and to switch the window used by the occupants to view the outside of the vehicle to a state in which photovoltaic power generation using visible light is possible when it is detected that the vehicle is not being driven. A vehicle according to claim 1, in which the usage detection means is configured to detect the remaining charge of an on-board battery as the usage status of the vehicle, and the window photovoltaic power generation state switching means is configured to switch at least those windows that are not used by occupants to view the outside of the vehicle to a state in which photovoltaic power generation using visible light is possible, according to the detected remaining charge of the on-board battery. A vehicle according to any one of claims 1 to 4, in which a transparent solar cell that generates electricity by absorbing light in a wavelength range other than the visible light range is installed on the window, and the window photoelectric power generation state switching means is configured to switch to a state in which photoelectric power generation is possible using the visible light by positioning a means for generating electricity using visible light on the interior side of the window on which the transparent solar cell is installed in a state in which it can receive sunlight that has passed through the window.

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