PHOTOVOLTAIC POWER SUPPLY DEVICE

A photovoltaic power supply device includes a base and a solar cell panel. The base is removably attached to a mobile terminal and includes a base surface (front surface). The solar cell panel is electrically connected to the base and includes a light receiving surface on an outer surface on one side in a thickness direction. Power generated by the solar cell panel is supplied to the mobile terminal via the base. The solar cell panel is supported by the base with a shaft. The position of the solar cell panel with respect to the base is variable. The position includes a retracted position in which the entirety of the solar cell panel overlaps with the base surface from the outside of the base, and a use position in which the solar cell panel does not overlap with the base surface outside the base and is tiltable about the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2023-163679, filed on Sep. 26, 2023, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a photovoltaic power supply device that includes a solar cell panel and supplies power generated by the solar cell panel to an electronic device such as a mobile terminal.

2. Description of Related Art

For example, as disclosed in Japanese Laid-Open Patent Publication No. 2016-42778, solar cells have been used to supply power to electronic devices such as smartphones in recent years. Additionally, as disclosed in Japanese Laid-Open Patent Publication No. 2015-142421, compact power supply devices that provide power to electronic devices without using a commercial power source have been proposed.

In this respect, as shown inFIG.19, it is conceivable to attach a small photovoltaic power supply device A, which is formed by fixing a solar cell panel202to a base204, to an electronic device201. Power generated by the solar cell panel202is supplied to the electronic device201through the base204.

However, as shown inFIG.20, when the user holds the photovoltaic power supply device A together with the electronic device201during use, a large portion of a light receiving surface203of the solar cell panel202is covered by the user's hand HA. In this case, the hand HA, which is between a light source LS such as the sun and the light receiving surface203, significantly blocks the light from the light source LS. The power generation efficiency of the solar cell panel202is reduced by an amount corresponding to the blocked light irradiation to the light receiving surface203.

SUMMARY

In one general aspect, a photovoltaic power supply device includes a base removably attached to an electronic device and including a base surface on an outer surface on one side in a thickness direction of the base, and a solar cell panel electrically connected to the base and including a light receiving surface on an outer surface on at least one side in a thickness direction of the solar cell panel. The photovoltaic power supply device is configured such that power generated by the solar cell panel is supplied to the electronic device via the base. The solar cell panel is supported by the base with a shaft. A position of the solar cell panel with respect to the base is variable. The position includes a retracted position in which the entirety of the solar cell panel overlaps with the base surface from the outside of the base or is accommodated inside the base, and a use position in which the solar cell panel does not overlap with the base surface outside the base and is tiltable about the shaft.

DETAILED DESCRIPTION

First Embodiment

A photovoltaic power supply device A according to a first embodiment will now be described with reference toFIGS.1to11.

The photovoltaic power supply device A is a device that is attached to an electronic device and supplies power generated by a solar cell panel to the electronic device.

As shown inFIGS.2and3, in the first embodiment, a mobile terminal10, which is a portable communication device such as a smartphone or a mobile phone, is an electronic device. A smartphone is a portable telephone terminal having many functions in addition to a call function as a mobile phone. A smartphone has, for example, an image capturing function provided by a camera and a web information display function like a personal computer.

The mobile terminal10has a rectangular plate-shaped outline. Although not illustrated, the mobile terminal10includes a CPU, a memory, a display, an input device, a communication device, and the like. As shown inFIG.10, the mobile terminal10includes a built-in power storage unit11composed of a rechargeable battery, and is configured to perform its own functions using the power storage unit11as a power source.

As shown inFIGS.1and3, the mobile terminal10incorporates camera at one end in the length direction. A lens12of the camera is exposed on a back surface13of the mobile terminal10.

The photovoltaic power supply device A includes a base20and a solar cell panel50.

As shown inFIGS.2and7, the base20includes a first functional portion21and a second functional portion31. In order to define each portion of the base20, two directions orthogonal to each other are referred to as a width direction and a length direction, and a direction orthogonal to both directions is referred to as a thickness direction.

The first functional portion21and the second functional portion31are adjacent to each other in the length direction. A dimension W1of the first functional portion21in the width direction is set to be the same as a dimension W2of the second functional portion31in the same direction. A dimension L2of the second functional portion31in the length direction is set to be greater than the dimension L1of the first functional portion21in the same direction.

As shown inFIGS.2and6, the first functional portion21has a rectangular cross section. As shown inFIG.7, the second functional portion31has the shape of a rectangular plate in which the dimension L2in the length direction is greater than the dimension W2in the width direction.

As shown inFIGS.2and6, an outer surface of the first functional portion21, which is on one side in the thickness direction of the base20, is referred to as a front surface22, and the surface on the other side is referred to as a back surface23. Further, as shown inFIGS.3and7, the surfaces on the opposite sides of the first functional portion21in the width direction of the base20are referred to as side surfaces24,25.

As shown inFIGS.2and6, an outer surface of the second functional portion31, which is on one side in the thickness direction, is referred to as a front surface32, and the surface on the other side is referred to as a back surface33. The back surface23of the first functional portion21and the back surface33of the second functional portion31are located on the same plane. Further, as shown inFIGS.3and7, the surfaces on the opposite sides of the second functional portion31in the width direction of the base20are referred to as side surfaces35,36.

As shown inFIG.2, a dimension T1of the first functional portion21in the thickness direction is set to be greater than a dimension T2of the second functional portion31in the same direction. The front surface22of the first functional portion21is disposed at a position more distant from the back surfaces23,33in the thickness direction than the front surface32of the second functional portion31is. As shown inFIGS.6and7, a stepped surface34extending in the thickness direction and the width direction is formed between the front surface22of the first functional portion21and the front surface32of the second functional portion31. The front surface32of the second functional portion31forms a base surface of the base20.

As shown inFIGS.2and6, the base20is detachably attached to the mobile terminal10with both of the back surfaces23,33placed against the back surface13of the mobile terminal10. For example, the base20is attached to a predetermined position on the mobile terminal10by using an attraction force of a magnet disposed in at least one of the interior of the second functional portion31in the base20and the interior of the mobile terminal10. The lens12is preferably exposed so that the camera can capture images even when the base20is attached to the mobile terminal10.

In a state in which the base20is attached to the mobile terminal10, the front surface22of the first functional portion21is disposed at a position more distant from the back surface13of the mobile terminal10in the thickness direction than the front surface32(base surface) of the second functional portion31is.

Further, the base20is formed to have a shape and a size that can be held together with the mobile terminal10. The size includes a thickness.

As shown inFIG.10, the base20includes a power receiving unit41, a power storage unit42, a power transmitting unit43, and a controlling unit44. The power receiving unit41is electrically connected to the solar cell panel50to receive power supplied from the solar cell panel50. An electrical connection structure (relay structure RS) between the power receiving unit41and the solar cell panel50will be discussed below.

The power storage unit42includes a rechargeable battery that can be repeatedly charged and discharged, such as a nickel-metal hydride battery or a lithium-ion rechargeable battery. The power transmitting unit43transmits (supplies) some of the power stored in the power storage unit42to the mobile terminal10. In the controlling unit44, for example, a hardware processor such as a CPU executes programs (software). The controlling unit44controls the transmission (supply) of power from the power transmitting unit43to the mobile terminal10. Based on the charging state of the power storage unit42, the controlling unit44controls the storage of power received through the power receiving unit41in the power storage unit42.

The power receiving unit41, the power storage unit42, a part of the power transmitting unit43, and the controlling unit44are disposed, for example, inside the first functional portion21of the base20.

Power is supplied from the power transmitting unit43to the mobile terminal10by a contactless (wireless) power transmission method capable of transmitting power without using a metal contact, a connector, or the like. This method is also called contactless power supply, contactless power transmission, or the like. In the first embodiment, contactless power transmission with an electromagnetic induction method is employed among non-radiation methods that can be used in a relatively close region. The power transmitting unit43includes, as a primary coil, a power transmitter coil (not shown), which generates a magnetic field (magnetic flux) when energized. The power transmitter coil is disposed inside the second functional portion31of the base20.

The mobile terminal10includes a power receiver coil (not shown) as a secondary coil. As shown inFIGS.2and6, when the back surfaces23,33of the base20are placed against and attracted to the back surface13of the mobile terminal10, the power transmitter coil and the power receiver coil are electromagnetically coupled together to convert a magnetic field into electric power. The converted power is stored in a power storage unit11(seeFIG.10) of the mobile terminal10.

Instead of the above-described electromagnetic induction method, a magnetic field resonance method, an electric field coupling method, a radio wave field coupling method, a radio wave receiving method, or the like may be used as a contactless power transmission method.

Solar Cell Panel50

As shown inFIG.1, the solar cell panel50has the shape of a thin plate extending in a planar manner. In the first embodiment, a thin-film solar cell51(seeFIG.5) such as a perovskite solar cell is employed as the solar cell panel50. The solar cell panel50has the shape of a rectangular plate. In order to define each portion of the solar cell panel50, two directions orthogonal to each other are referred to as a width direction and a length direction, and a direction orthogonal to both directions is referred to as a thickness direction. As shown inFIGS.6and7, the solar cell panel50includes two side surfaces52,53and two end faces54,55. The side surfaces52,53are on the opposite sides in the width direction and extend in the length direction while being parallel with each other. The end faces54,55are on the opposite sides in the length direction and extend in the width direction while being parallel with each other. The solar cell panel50includes a light receiving surface56, which is one of the surfaces on the opposite sides in the thickness direction. In the first embodiment, the light receiving surface56is a surface on the opposite side to the front surface32of the second functional portion31.

FIG.5shows a schematic configuration of the thin-film solar cell51.

Portions on the opposite sides in the thickness direction (lateral direction inFIG.5) of the thin-film solar cell51are formed by two base members61,75, respectively. The base members61,75are made of a transparent or translucent material that is transmissive to light, for example, a plastic film, glass, or the like.

The thin-film solar cell51includes a power generation layer66, a hole transport layer67, an electron transport layer68, positive electrodes62,71, negative electrode63, and a sealing material74between the base members61,75.

The power generation layer66is a layer that absorbs light generated by the light source LS and performs photoelectric conversion. The light source LS is typically the sun, but may be a light device or the like.

The power generation layer66is made of a metal halide material having a perovskite structure (hereinafter, referred to as a “perovskite compound”). The perovskite compound has an octahedral crystal structure represented by the formula AMX3, where A is a monovalent cation, M is a divalent metal cation, and X is a halide ion.

The hole transport layer67and the electron transport layer68are disposed on the opposite sides of the power generation layer66in the thickness direction. The hole transport layer67is disposed on the power generation layer66and located between the power generation layer66and the base member75. The electron transport layer68is disposed on the power generation layer66and located between the power generation layer66and the base member61.

The positive electrodes62,71are electrically connected to the hole transport layer67. The positive electrode62is disposed on the base member61and is located between the base member61and the base member75. In other words, the positive electrode62is stacked on the inner surface of the base member61in the thickness direction. A part of the positive electrode62is located between the base member61and the electron transport layer68.

The positive electrode71includes an electrode body72and an electrode connector portion73. The entire positive electrode71is made of a conductive metal. The electrode body72is stacked on a surface of the hole transport layer67on the side opposite to the power generation layer66(side closer to the base member75). The electrode connector portion73extends in the thickness direction of the thin-film solar cell51and passes through the hole transport layer67, the power generation layer66, and the electron transport layer68. One end of the electrode connector portion73is connected to the electrode body72, and the other end is connected to the positive electrode62. A wiring member64is connected to the positive electrode62.

The negative electrode63is connected to the electron transport layer68. The negative electrode63is stacked on an inner surface of the base member61in the thickness direction at a position separated from the positive electrode62. A part of the negative electrode63is located between the base member61and the electron transport layer68. A wiring member65is connected to the negative electrode63.

The positive electrode62and the negative electrode63are both made of a transparent or translucent material that is transmissive to light and has electrical conductivity. For example, the positive electrode62and the negative electrode63are made of a metal oxide film such as indium tin oxide (ITO) or zinc oxide (ZnO).

The sealing material74is located between the base member75and the set of the positive electrode62and the negative electrode63, and covers the power generation layer66, the hole transport layer67, the electron transport layer68, and the electrode body72.

In the thin-film solar cell51having the above-described configuration, the surface of the base member61on the side opposite to the base member75, that is, a surface of the base member61on one side in the thickness direction of the thin-film solar cell51, forms the light receiving surface56.

Support Structure SS

As shown inFIGS.3,4,7, and8, the solar cell panel50is mechanically supported by the base20with the following support structure SS.

In a state in which the solar cell panel50is supported by the base20, a protrusion81protrudes from a part of the outer periphery of the solar cell panel50. The protrusion81protrudes toward the first functional portion21from a portion near the side surface53on the end face54close to the first functional portion21. A distal end face of the protrusion81in the protruding direction is formed by a curved surface81athat bulges toward the first functional portion21. The curved surface81ais provided to prevent the protrusion81and the stepped surface34of the first functional portion21from contacting each other when the solar cell panel50is tilted. A shaft82extending along a first axis AL1parallel with the width direction is fixed to the protrusion81. The shaft82protrudes from the protrusion81toward the side surface53.

A shaft receiving portion26protrudes from the stepped surface34of the first functional portion21. The shaft receiving portion26protrudes from a position adjacent to the side surface25on one side of the first functional portion21toward the end face54of the solar cell panel50. The shaft receiving portion26includes a curved surface26aformed by rounding at a boundary between a surface opposite to the first functional portion21and a surface opposite to the front surface32of the second functional portion31. The curved surface26ais provided to prevent the shaft receiving portion26and the end face54of the solar cell panel50from contacting each other when the solar cell panel50is tilted.

The shaft receiving portion26includes a shaft receiving hole27at a position on the same line as the first axis AL1. The shaft receiving hole27opens in an end face26bof the shaft receiving portion26. The end face26bis closer to the side surface24(the protrusion81). The shaft receiving hole27extends toward the side surface25along the first axis AL1. The shaft82is removably inserted into the shaft receiving hole27by a relative movement of the base20and the solar cell panel50.

Relay Structure RS

As shown inFIGS.3,7, and9, the solar cell panel50is connected to the base20by a relay structure RS discussed below such that the solar cell panel50and the base20can be electrically disconnected. This disconnectable connection is established by relative movement of the base20and the solar cell panel50.

The base20is provided with a connectable portion, and the solar cell panel50is provided with a connection portion. The connectable portion and the connection portion are formed by a combination of a connection hole29and a terminal portion84that extend along a second axis AL2that is positioned on the same line as the first axis AL1.

In the first embodiment, the connection hole29is provided as a connectable portion, and the terminal portion84is provided as a connection portion. Specifically, a protrusion28protrudes from the stepped surface34of the first functional portion21. The protrusion28protrudes toward the solar cell panel50from a portion of the stepped surface34between the shaft receiving portion26and the side surface24. The protrusion28includes a curved surface28aformed by rounding the boundary between the surface opposite to the first functional portion21and the surface opposite to the front surface32of the second functional portion31. The curved surface28ais provided to prevent the protrusion28and the end face54of the solar cell panel50from contacting each other when the solar cell panel50is tilted.

The connection hole29opens in an end face28bof the protrusion28that is closer to the side surface24. The connection hole29extends along the second axis AL2toward the side surface25. An inner wall surface29aof the connection hole29includes a positive-terminal receiving portion and a negative-terminal receiving portion (neither is shown), which are insulated from each other. The positive-terminal receiving portion and the negative-terminal receiving portion are connected to the power receiving unit41(seeFIG.10) in the base20.

A protrusion83protrudes from the end face54of the solar cell panel50. The protrusion83protrudes from a portion of the end face54close to the side surface52toward the stepped surface34of the first functional portion21. A distal end face of the protrusion83in the protruding direction includes a curved surface83athat bulges toward the first functional portion21. The curved surface83ais provided to prevent the protrusion83and the stepped surface34of the first functional portion21from contacting each other when the solar cell panel50is tilted.

The terminal portion84is fixed to the protrusion83. The terminal portion84protrudes along the second axis AL2from the protrusion83toward the side surface53.

The terminal portion84includes a positive terminal portion and a negative terminal portion (neither is shown), which are insulated from each other. The positive electrode62is electrically connected to the positive terminal portion via the wiring member64. The negative electrode63is electrically connected to the negative terminal portion via the wiring member65.

The terminal portion84is removably inserted into the connection hole29as the shaft82is inserted into the shaft receiving hole27. The terminal portion84inserted into the connection hole29is supported by the inner wall surface29aso as to rotate about the second axis AL2while being in contact with the inner wall surface29a.

The state in which the terminal portion84is in contact with the inner wall surface29ais a state in which the terminal portion84and the connection hole29are electrically connected to each other. Specifically, the positive terminal portion is in contact with and electrically connected to the positive-terminal receiving portion, and the negative terminal portion is in contact with and electrically connected to the negative-terminal receiving portion.

As the shaft82is removed from the shaft receiving hole27, the terminal portion84is removed from the connection hole29, so that the electrical connection of the terminal portion84to the connection hole29is discontinued.

Position of Solar Cell Panel50

The solar cell panel50can change its position with respect to the base20. The position includes a retracted position and a use position.

As indicated by solid lines inFIG.2, the retracted position is a position in which the entire solar cell panel50overlaps with the front surface32(base surface) of the second functional portion31from the outside of the base20. In the retracted position, the solar cell panel50is parallel with the front surface32and is not tilted with respect to the front surface32.

As indicated by long-dash double-short-dash lines inFIG.2, the use position is a position in which the entire solar cell panel50does not overlap with the front surface32(base surface) outside the base20and can tilt about the shaft82. In the use position, the solar cell panel50is tilted with respect to the front surface32.

As shown inFIG.8, the shaft82is press-fitted into the shaft receiving hole27. Friction is generated between the outer circumferential surface of the shaft82and the inner wall surface27aof the shaft receiving hole27. This friction is set to a magnitude that enables angle adjustment of the solar cell panel50in the use position with respect to the base20.

The angle adjustment refers to changing the tilt angle of the solar cell panel50with respect to the base20within a specified angle range and maintaining the solar cell panel50at the changed tilt angle. The tilt angle is changed by tilting the solar cell panel50about the shaft82.

In addition, when the solar cell panel50is tilted by the hand HA, a load of an appropriate magnitude is generated as an operation load due to friction.

When an external force large enough to overcome the friction is applied to the solar cell panel50in the thickness direction, the solar cell panel50is tilted about the shaft82. In contrast, when an external force is applied to the solar cell panel50but the external force is smaller than the magnitude that overcomes the friction, or when no external force is applied, the solar cell panel50is maintained at the tilt angle at that time.

Operation of the first embodiment, which is configured as described above, will now be described.

Power Supply to Mobile Terminal10

As shown inFIG.2, the photovoltaic power supply device A is attached to the back surface13of the mobile terminal10, which is compatible with contactless power supply, in the base20. Specifically, the base20is attracted to the mobile terminal10by the magnetic force of the magnet while the back surfaces23,33of the base20are placed against the back surface13with the positions of the back surfaces23,33determined. As the base20is attached to the mobile terminal10, the power transmitter coil of the solar cell panel50and the power receiver coil of the mobile terminal10are electromagnetically coupled to each other, so that the photovoltaic power supply device A is electrically connected to the mobile terminal10.

As shown inFIG.10, the power stored in the power storage unit42of the base20is transmitted to the mobile terminal10by contactless power supply by the controlling unit44controlling the power transmitting unit43, and is stored in the power storage unit11. Power can be supplied from the photovoltaic power supply device A to the mobile terminal10regardless of the position of the solar cell panel50.

As shown inFIG.11, the mobile terminal10operates using the power stored in the power storage unit11, enabling its calling and communication functions. The mobile terminal10can operate with or without the photovoltaic power supply device A attached to the mobile terminal10. Furthermore, when the solar power supply device A is attached, the mobile terminal10can function regardless of the position of the solar cell panel50.

Power Generation and Power Storage by Photovoltaic Power Supply Device A

As shown inFIG.5, the thin-film solar cell51of the solar cell panel50includes the base member61, which includes the light receiving surface56, and the base member61and the member located between the base member61and the power generation layer66are transmissive to light. Therefore, in the photovoltaic power supply device A, when the light receiving surface56of the solar cell panel50is directed to the light source LS, the light receiving surface56is irradiated with the light of the light source LS. The solar cell panel50generates power having a magnitude corresponding to the amount of light with which the light receiving surface56is irradiated. Specifically, some of the light applied to the light receiving surface56is transmitted through the base member61, the positive electrode62, and the electron transport layer68, and reaches the power generation layer66. The remaining light passes through the base member61, the negative electrode63, and the electron transport layer68, and reaches the power generation layer66. Further, the remaining light passes through the base member61and the electron transport layer68, and reaches the power generation layer66.

In the power generation layer66, holes and electrons are generated by photoexcitation. The holes are transported to the positive electrodes71,62by the hole transport layer67. The electrons are transported to the negative electrode63by the electron transport layer68. Then, a current is extracted from the wiring member64, connected to the positive electrode62, and the wiring member65, connected to the negative electrode63.

Power generation is possible by directing the light receiving surface56of the solar cell panel50in the retracted position shown inFIGS.2and3toward the light source LS. Power generation is also possible by directing the light receiving surface56of the solar cell panel50in the use position toward the light source LS. At this time, as shown inFIG.1, the light receiving surface56may be directed toward the light source LS by tilting the solar cell panel50in a state in which the base20is held together with the mobile terminal10.

Further, as shown inFIG.11, the photovoltaic power supply device A in a state in which the solar cell panel50is tilted with respect to the base20may be placed on a flat surface FS such as a desk without being held by the hand HA. In this case, both the base20and the solar cell panel50are placed in a state of being tilted with respect to the flat surface FS. Power can be generated by the solar cell panel50while the mobile terminal10is maintained in a tilted state by the photovoltaic power supply device A. At this time, the mobile terminal10in the tilted state may be used for a call, communication, or the like.

Although not illustrated, power generation is also possible when the photovoltaic power supply device A is used alone without being attached to the mobile terminal10.

As shown inFIGS.5,9, and10, the power generated by the solar cell panel50is supplied to the power receiving unit41via the wiring members64,65, the terminal portion84, and the connection hole29. The power is then stored in the power storage unit42by the controlling unit44controlling the power receiving unit41.

Reduction of Decrease in Power Generation Efficiency of Solar Cell Panel50

In the use of the mobile terminal10to which the photovoltaic power supply device A is attached, the mobile terminal10may be held by the hand HA with the solar cell panel50in the retracted position. In this case, the light receiving surface56may be covered by the hand HA. This is because, in the retracted position, the solar cell panel50overlaps with the front surface32(base surface) from the outside of the base20as indicated by the solid lines inFIG.2, so that the photovoltaic power supply device A has a compact shape and size suitable for gripping. Specifically, when the solar cell panel50is in the retracted position, the photovoltaic power supply device A is in the same state as the photovoltaic power supply device A in the related art, in which a solar cell panel202is fixed to a base204, as shown inFIGS.19and20. In this case, the hand HA is located between the light source LS and the light receiving surface56, and irradiation of light to the light receiving surface56is largely blocked by the hand HA. Since the light is blocked by the hand HA, the amount of light with which the light receiving surface56is irradiated decreases, and the power generation efficiency of the solar cell panel50decreases.

In this regard, as shown inFIG.2, the solar cell panel50is tiltable about the shaft82. In addition, as shown inFIG.8, a friction large enough to enable the angle adjustment of the solar cell panel50with respect to the base20is generated between the shaft82and the inner wall surface27aof the shaft receiving hole27.

As shown inFIG.3, the terminal portion84, which is on the same line as the shaft82, supports the solar cell panel50in an auxiliary manner so that the solar cell panel50is tiltable with respect to the base20.

The solar cell panel50in the retracted position receives an external force in the thickness direction by the hand HA. When an external force large enough to overcome the friction is applied to the solar cell panel50, the solar cell panel50is tilted about the shaft82. As a result of this tilting, the solar cell panel50is brought into the use position, in which the solar cell panel50does not overlap with the front surface32(base surface) outside the base20.

When an external force is applied to the solar cell panel50, but the external force is smaller than the magnitude overcoming the friction, or when no external force is applied, the solar cell panel50is maintained at the tilt angle at that time due to the friction. Therefore, the magnitude of the external force applied to the solar cell panel50is varied to adjust the tilt angle of the solar cell panel50with respect to the base20and to maintain the solar cell panel50at the adjusted tilt angle.

When the tilt angle of the solar cell panel50with respect to the base20increases to some extent, a space into which fingers FI can be inserted is created around the base20and between the base20and the solar cell panel50. As shown inFIG.1, when the fingers FI are put in this space, the user can hold the photovoltaic power supply device A together with the mobile terminal10with little or no holding of the solar cell panel50. The mobile terminal10can be used (operated) while the solar cell panel50generates electric power. The portion of the hand HA between the light source LS and the light receiving surface56is reduced or eliminated, and the irradiation of light to the light receiving surface56is less likely to be significantly blocked by the hand HA. The light receiving surface56is irradiated with a larger amount of light than in the photovoltaic power supply device A of a related art, in which irradiation of light is largely blocked by the hand HA.

In addition, in the use position, when the solar cell panel50is tilted around the shaft82to direct the light receiving surface56to the light source LS, more light is irradiated on the light receiving surface56.

When the position of the solar cell panel50is changed, the shaft82is rotated around the first axis AL1in the shaft receiving hole27as shown inFIG.8. With the rotation of the shaft82, the terminal portion84is rotated about the second axis AL2in the connection hole29, as shown inFIG.9. The terminal portion84is rotated in a state in which the terminal portion84is in contact with the inner wall surface29aof the connection hole29, that is, in a state in which electrical connection is maintained, without hindering rotation of the shaft82with respect to the shaft receiving hole27.

Replacement of Solar Cell Panel50

When the solar cell panel50malfunctions, the base20and the solar cell panel50are moved relative to each other in a direction along the first axis AL1and the second axis AL2in which the shaft82moves away from the shaft receiving hole27and the terminal portion84moves away from the connection hole29. Then, as shown inFIG.7, the shaft82is removed from the shaft receiving hole27, and the solar cell panel50is no longer supported by the base20with the shaft receiving hole27and the shaft82. Further, the terminal portion84is removed from the connection hole29, and the connection of the connection portion to the connectable portion is discontinued. The electrical connection of the solar cell panel50to the base20is disconnected.

The solar cell panel50is removed from the base20. Therefore, the solar cell panel50can be repaired in a detached state. The solar cell panel50can be repaired at a place away from the base20.

The solar cell panel50after repair or another solar cell panel50that is not malfunctioning is referred to as a new solar cell panel50.

The base20and the new solar cell panel50are moved relative to each other in opposite directions. The opposite directions are directions along the first axis AL1and the second axis AL2and include a direction in which the shaft82approaches the shaft receiving hole27and a direction in which the terminal portion84approach the connection hole29. Then, the shaft82is inserted into the shaft receiving hole27, and the new solar cell panel50is tiltably supported by the base20with the shaft82. In addition, the terminal portion84is inserted into the connection hole29, so that the new solar cell panel50is electrically connected to the base20via the terminal portion84and the connection hole29. In this manner, the malfunctioning solar cell panel50is replaced with a functioning solar cell panel50.

In addition, when the solar cell panel50is replaced with a solar cell panel having a different design, the shaft82is removed from the shaft receiving hole27by relative movement of the base20and the solar cell panel50in the same manner as described above. Further, the terminal portion84is removed from the connection hole29. The solar cell panel50is thus removed from the base20.

By the relative movement in the direction opposite to the above, the shaft82of the solar cell panel50having a different design is inserted into the shaft receiving hole27, and the terminal portion84is inserted into the connection hole29. Then, the solar cell panel50having a design different from that of the solar cell panel50before replacement is tiltably supported by the base20with the shaft82, and is electrically connected to the base20via the terminal portion84and the connection hole29. In this manner, the solar cell panel50is replaced with a solar cell panel50having a different design.

The first embodiment has the following advantages.

(1-1) As shown inFIG.2, the solar cell panel50is supported by the base20with the shaft82. The position of the solar cell panel50with respect to the base20can be changed by tilting the solar cell panel50about the shaft82.

Therefore, by bringing the solar cell panel50into the use position, the user can hold the photovoltaic power supply device A together with the mobile terminal10without holding the solar cell panel50at all or without holding a large part of the solar cell panel50. It is possible to prevent the irradiation of light to the light receiving surface56from being largely blocked by the hand HA, and to reduce the decrease in the power generation efficiency of the solar cell panel50due to the blocking.

In addition, in the use position, the solar cell panel50is tilted about the shaft82to direct the light receiving surface56toward the light source LS. This allows the light receiving surface56to be irradiated with more light and thus increases the power generation efficiency of the solar cell panel50.

(1-2) In the use position, the solar cell panel50is tilted with respect to the base20as indicated by the long-dash double-short-dash lines inFIG.2. Therefore, the size of the entire photovoltaic power supply device A in the thickness direction is increased.

In the first embodiment, when the solar cell panel50is brought into the retracted position, the entire solar cell panel50overlaps with the front surface32(base surface) as indicated by the solid lines inFIG.2. Therefore, the overall size of the photovoltaic power supply device A in the thickness direction is reduced in the retracted position than in the use position.

(1-3) As shown inFIGS.7to9, the solar cell panel50is provided with the shaft82, and the base20is provided with the shaft receiving portion26, which includes the shaft receiving hole27. The shaft82is removably inserted into the shaft receiving hole27by relative movement of the base20and the solar cell panel50. The base20is provided with a connectable portion, and the solar cell panel50is provided with a connection portion. The connection portion is connected to the connectable portion by the relative movement such that the connection portion and the connectable portion can be electrically disconnected.

Thus, if the solar cell panel50malfunctions, it can be removed from the base20and repaired. The repaired solar cell panel50, or another solar cell panel50that is not malfunctioning, can be attached to the base20. Further, the solar cell panel50can be replaced with a solar cell panel having a different design.

There is no need to replace or repurchase the base20.

(1-4) As shown inFIGS.7to9, the shaft82and the shaft receiving hole27extend along the first axis AL1. The connectable portion and the connection portion are formed by a combination of a connection hole29and a terminal portion84that extend along a second axis AL2that is positioned on the same line as the first axis AL1. The terminal portion84is removably inserted into the connection hole29as the shaft82is inserted into the shaft receiving hole27. When the terminal portion84inserted into the connection hole29, the terminal portion84is supported by the inner wall surface29aof the connection hole29so as to rotate about the second axis AL2while being in contact with the inner wall surface29a.

Therefore, despite its simple structure, the solar cell panel50can be selectively supported by the base20or not by moving the base20and the solar cell panel50relative to each other in directions along the first axis AL1and the second axis AL2. In addition, the solar cell panel50can be selectively electrically connected to and disconnected from the base20.

(1-5) By employing the configuration of item (1-4), the shaft82can be rotated in the shaft receiving hole27and the terminal portion84can be rotated in the connection hole29, while maintaining the electrical connection. Further, it is possible to prevent the terminal portion84and the connection hole29from hindering rotation of the shaft82in the shaft receiving hole27.

(1-6) As shown inFIG.8, the friction generated between the shaft82and the inner wall surface27aof the shaft receiving hole27when the shaft82is press-fitted into the shaft receiving hole27is set to such a magnitude that the angle of the solar cell panel50with respect to the base20can be adjusted.

Therefore, by varying the magnitude of the external force applied to the solar cell panel50in the thickness direction, the tilt angle of the solar cell panel50with respect to the base20can be adjusted, and the solar cell panel50can be maintained at the adjusted tilt angle.

(1-7) As shown inFIG.10, the base20includes the power storage unit42, which stores power generated by the solar cell panel50, and the power transmitting unit43, which transmits the power stored in the power storage unit42to the mobile terminal10by contactless power supply.

Therefore, even if the mobile terminal10is not connected to the base20of the photovoltaic power supply device A by a cable or the like, the transmitted power can be received and stored in the power storage unit11. The power storage unit11can be easily charged by attaching the photovoltaic power supply device A to the mobile terminal10without concern for the connection state between the mobile terminal10and the photovoltaic power supply device A. In addition, since it is not necessary to carry a cable, convenience is improved.

(1-8) As shown inFIGS.1and3, the photovoltaic power supply device A is attached to the mobile terminal10at a position separated from the lens12. This allows the camera to capture images with the photovoltaic power supply device A attached to the mobile terminal10.

Second Embodiment

A photovoltaic power supply device A according to a second embodiment will now be described with reference toFIGS.12and13.

Similarly to the first embodiment, a solar cell panel50according to the second embodiment has the shape of a rectangular plate.

A base20has the shape of a rectangular plate. Although the shape of the base20is slightly different from the shape described in the first embodiment, the base20includes a power receiving unit41, a power storage unit42, a power transmitting unit43, and a controlling unit44shown inFIG.10.

The dimension of the base20in the width direction is greater than the dimension of the solar cell panel50in the same direction. The dimension of the base20in the length direction is greater than the dimension of the solar cell panel50in the same direction.

As shown inFIGS.12and13, an outer surface of the base20, which is on one side in the thickness direction, will be referred to as a front surface37, and the surface on the other side will be referred to as a back surface38. In a state in which the photovoltaic power supply device A is attached to the mobile terminal10, the front surface37is located on the opposite side to the back surface13of the mobile terminal10, and the back surface38faces (is in contact with) the back surface13.

The base20has a base surface that includes at least a part of the front surface37(the entire front surface37in the second embodiment). The base20includes an accommodating portion91for the solar cell panel50. The accommodating portion91is a space that has a size capable of accommodating the entire solar cell panel50, for example, a size slightly larger than the solar cell panel50. The accommodating portion91extends in directions orthogonal to the thickness direction of the base20, more specifically, in both the length direction and the width direction. The accommodating portion91opens in a part of the outer periphery of the base20. In the second embodiment, the accommodating portion91opens in an end face92on one side in the length direction of the base20. The end face92is one of the end faces on the opposite sides in the length direction. Specifically, the end face92is an end face on the side opposite to the lens12in a state in which the base20is attached to the mobile terminal10.

Grooves93extending in the length direction are formed at two positions on the inner wall surface91aof the accommodating portion91that face each other in the width direction.

The solar cell panel50includes shafts85that protrude from the side surfaces52,53(only the side surface53on one side is shown inFIGS.12and13). Each of the shafts85protrudes outward in the width direction from one end in the length direction. The shafts85are positioned on the same line.

The solar cell panel50is accommodated in the accommodating portion91in a manner that allows the shafts85to slide within the grooves93. In other words, the solar cell panel50is arranged to be slidable relative to the base20in a direction orthogonal to the thickness direction.

A relay mechanism (not shown) that electrically connects the solar cell panel50and the base20to each other is provided therebetween. For example, a relay mechanism may be configured such that one of the shafts85has the same configuration as the connection portion (the terminal portion84) in the first embodiment, and that the groove93with which that shaft85engages has the same configuration as the connectable portion (the connection hole29) in the first embodiment.

In the second embodiment, a position in which the entire solar cell panel50is accommodated in the accommodating portion91, that is, a position in which the entire solar cell panel50is accommodated inside the base20is referred to as a retracted position. In the retracted position, the shafts85are engaged with the grooves93at a position close to an end face on one of the opposite sides in the length direction of the base20, specifically, at a position close to the end face opposite to the end face92. A position in which the solar cell panel50does not overlap with the front surface37(base surface) outside the base20and can be tilted about the shafts85is referred to as the use position. The use position in the present embodiment is a position in which a large part of the solar cell panel50is out of the accommodating portion91in a state in which the shaft85are positioned at one end in the length direction of the corresponding groove93, that is, in a state in which the shafts85remain in the base20. In the use position, a portion of the solar cell panel50that is supported by the base20with the shafts85is located inside the base20, and a portion of the solar cell panel50different from the supported portion is located outside the base20. The use position includes not only a position in which the solar cell panel50is tilted with respect to the front surface37(base surface), but also a position in which the solar cell panel50is parallel with the front surface37(see solid lines inFIG.13). In the use position, the solar cell panel50is tiltable with respect to the base20about the shafts85.

In the use position, the friction generated between the shafts85and inner wall surfaces93aof the grooves93is set to such a magnitude that the angle of the solar cell panel50with respect to the base20can be adjusted as in the first embodiment.

In addition, in the second embodiment, a solar cell panel having a configuration slightly different from that used in the first embodiment is used as the solar cell panel50. As shown inFIG.5, the thin-film solar cell51includes a power generation layer66, a hole transport layer67, an electron transport layer68, positive electrodes62,71, negative electrode63, and a sealing material74between the base members61,75.

The base member61and a member located between the base member61and the power generation layer66are made of a transparent or translucent material that is transmissive to light. This feature is the same as that of the first embodiment. In addition to this, in the second embodiment, the base member75and a member located between the base member75and the power generation layer66are made of a transparent or translucent material that is transmissive to light. The corresponding members include the hole transport layer67, the positive electrode71, and the sealing material74.

Both an outer surface on one side of the base member61in the thickness direction and an outer surface on one side of the base member75in the thickness direction each form the light receiving surface56. The thin-film solar cell51thus has the light receiving surfaces56on the opposite surfaces in the thickness direction. Regardless of which light receiving surface56is irradiated with light, the light reaches the power generation layer66.

In the second embodiment, opposite side portions in the thickness direction of the accommodating portion91in the base20shown inFIGS.12and13are made of an opaque material having a low light transmissivity.

In the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and detailed explanations are omitted.

Next, operation of the photovoltaic power supply device A according to the second embodiment configured as described above will be described focusing on differences from the first embodiment.

Power Supply to Mobile Terminal10

The photovoltaic power supply device A is attached to the back surface13of the mobile terminal10, which is compatible with contactless power supply, on the back surface38of the base20. Specifically, the base20is attracted to a predetermined position on the mobile terminal10by the magnetic force of the magnet while the back surface38is placed against the back surface13with the position of the back surface38determined. This attachment is preferably performed in a state in which the lens12is exposed so that the camera can capture images even in a state in which the photovoltaic power supply device A is attached to the mobile terminal10. Through this attachment, the mobile terminal10is electrically connected to the photovoltaic power supply device A.

As shown inFIG.10, the power stored in the power storage unit42of the base20is transmitted to the mobile terminal10by contactless power supply, and is stored in the power storage unit11, as in the first embodiment. Power can be supplied from the photovoltaic power supply device A to the mobile terminal10regardless of the position of the solar cell panel50.

The mobile terminal10operates using the power stored in the power storage unit11, enabling its calling and communication functions. The mobile terminal10can operate with or without the photovoltaic power supply device A attached to the mobile terminal10. Furthermore, when the solar power supply device A is attached, the mobile terminal10can function regardless of the orientation of the solar cell panel50.

Power Generation and Power Storage by Photovoltaic Power Supply Device A

In the retracted position, the entire solar cell panel50is accommodated in the accommodating portion91. The light receiving surfaces56are both located in the accommodating portion91. The light from the light source LS does not reach or barely reaches the accommodating portion91. Therefore, the solar cell panel50does not generate power not only when the photovoltaic power supply device A is not held, but also when the photovoltaic power supply device A is held together with the mobile terminal10.

When the photovoltaic power supply device A generates power, an external force is applied to a portion of the solar cell panel50exposed from the accommodating portion91in a direction in which the solar cell panel50is removed from the accommodating portion91of the base20. As shown inFIGS.12and13, this external force causes the shafts85of the solar cell panel50to slide along the grooves93. The direction of the sliding movement is a direction away from the lens12of the mobile terminal10along the length of the base20.

When the shafts85slide to one end of the grooves93, the solar cell panel50is brought into the use position. The lens12of the mobile terminal10is not covered by the solar cell panel50in the use position. Even in a state in which the solar cell panel50is in the use position, the camera can capture images.

In the use position, both of the light receiving surfaces56are exposed from the accommodating portion91.

In the use position, a portion of the solar cell panel50that is supported by the base20with the shafts85is located inside the base20, and a portion of the solar cell panel50different from the supported portion is located outside the base20. The solar cell panel50is tilted with respect to the base20about the shaft85so that one of the light receiving surfaces56faces the light source LS. The light from the light source LS is irradiated on the light receiving surface56facing the light source LS.

When the light of the light source LS shown inFIG.5is irradiated on the light receiving surface56of the base member61, the light is transmitted through the base member61and transmitted through a member (including the electron transport layer68) disposed between the base member61and the power generation layer66, to reach the power generation layer66.

When the light of the light source LS (not shown) is irradiated on the light receiving surface56of the base member75, the light is transmitted through the base member75, is transmitted through a member (including the hole transport layer67) disposed between the base member75and the power generation layer66, and reaches the power generation layer66.

When the light reaches the power generation layer66as described above, holes and electrons are generated by photoexcitation in the power generation layer66. The holes are transported to the positive electrode71,62by the hole transport layer67, and the electrons are transported to the negative electrode63by the electron transport layer68. Then, a current is extracted from the wiring member64, connected to the positive electrode62, and the wiring member65, connected to the negative electrode63.

Therefore, even in a case in which the light receiving surface56of any of the base members61,75is directed toward the light source LS, power having a magnitude corresponding to the amount of light with which the light receiving surface56is irradiated is generated in the power generation layer66.

As long as the solar cell panel50is in the use position, power generation is possible even in a state in which the photovoltaic power supply device A is attached to the mobile terminal10or in a case in which the photovoltaic power supply device A is used alone without being attached to the mobile terminal10.

Power generation is also possible by directing the light receiving surface56of the solar cell panel50in the use position toward the light source LS. At this time, as shown inFIG.12, the solar cell panel50may be tilted in a state in which the base20is held together with the mobile terminal10. Since the lens12is not blocked by the solar cell panel50, the camera can capture images.

Further, as shown inFIG.13, the photovoltaic power supply device A attached to the mobile terminal10may be placed on a flat surface FS such as a desk without being held. In this case, the front surface37(base surface) of the base20is placed against the flat surface FS. The mobile terminal10is placed on the base20. As indicated by solid lines inFIG.13, the solar cell panel50is removed from the accommodating portion91to be in the use position. The solar cell panel50is tilted about the shaft85in correspondence with the position of the light source LS such that the light receiving surface56faces the light source LS, as indicated by the long-dash double-short-dash lines inFIG.13.

In this manner, even in a state in which the photovoltaic power supply device A is placed on the flat surface FS, it is possible to irradiate the light receiving surface56with a large amount of light by adjusting the orientation of the light receiving surface56in correspondence with the position of the light source LS. At this time, the mobile terminal10may be used for a call, communication, or the like.

Although not illustrated, power generation is also possible when the photovoltaic power supply device A is used alone without being attached to the mobile terminal10.

As described above, power generated by the solar cell panel50is supplied to the power receiving unit41shown inFIG.10via the wiring members64,65, the shafts85, and the grooves93. The power is then stored in the power storage unit42by the controlling unit44controlling the power receiving unit41.

Reduction of Decrease in Power Generation Efficiency of Solar Cell Panel50

When the mobile terminal10to which the photovoltaic power supply device A is attached is used, if the solar cell panel50is in the retracted position, the light of the light source LS does not reach the solar cell panel50, and power is not generated as described above.

When the solar cell panel50is in the use position as shown inFIG.12, the solar cell panel50is tiltable about the shafts85located at one end of the grooves93. In addition, as in the first embodiment, friction large enough to allow the angle of the solar cell panel50to be adjusted is generated between the shafts85and the inner wall surfaces93aof the grooves93.

Therefore, when the mobile terminal10is used, an external force by the fingers FI is applied to the solar cell panel50in the use position in the thickness direction. When an external force large enough to overcome the friction is applied to the solar cell panel50, the solar cell panel50is tilted about the shaft85. This tilting action changes the tilt angle of the solar cell panel50with respect to the base20. The tilting is performed in a state in which the shafts85are in contact with the inner wall surfaces93aof the grooves93, that is, in a state in which the shafts85are electrically connected to the power receiving unit41(seeFIG.10) in the base20.

When an external force smaller than the above-mentioned magnitude is applied to the solar cell panel50, or when no external force is applied, the solar cell panel50is maintained at the tilt angle at that time by friction. Therefore, the magnitude of the external force applied to the solar cell panel50is varied to adjust the tilt angle of the solar cell panel50with respect to the base20and to maintain the solar cell panel50at the adjusted tilt angle.

In the use position, the solar cell panel50is located outside the base20and does not overlap with the front surface37(base surface). If the tilt angle of the solar cell panel50with respect to the base20is not significantly small, a space into which the fingers FI can be inserted is formed around the base20and between the solar cell panel50and the base20. When fingers are put in this space, it is possible to hold the photovoltaic power supply device A together with the mobile terminal10without holding the solar cell panel50as shown inFIG.12. The portion of the hand HA between the light source LS and the light receiving surface56is reduced or eliminated, and the irradiation of light to the light receiving surface56is less likely to be significantly blocked by the hand HA. The light receiving surface56is irradiated with a larger amount of light than in the photovoltaic power supply device A of a related art, in which irradiation of light is largely blocked by the hand HA.

Further, in the use position, the light receiving surface56can be directed toward the light source LS by tilting the solar cell panel50about the shafts85. Directing the light receiving surface56toward the light source LS allows the light receiving surface56to be irradiated with a greater amount of light.

The photovoltaic power supply device A according to the second embodiment has the following advantages. The second embodiment has the following advantages in addition to the advantages of the items (1-7) and (1-8).

(2-1) The solar cell panel50is supported by the base20with the shafts85. The position of the solar cell panel50with respect to the base20can be changed by tilting the solar cell panel50about the shaft85.

Therefore, bringing the solar cell panel50into the use position prevents the irradiation of light to the light receiving surface56from being blocked by the hand HA, and directing the light receiving surface56toward the light source LS allows the light receiving surface56to be irradiated with a greater amount of light. Accordingly, similarly to the advantage of item (1-1), it is possible to increase the power generation efficiency of the solar cell panel50while using the mobile terminal10.

(2-2) In the use position, a portion of the solar cell panel50that is supported by the base20with the shafts85is located inside the base20, and a portion of the solar cell panel50different from the supported portion is located outside the base20. Therefore, in the use position, the size of the entire photovoltaic power supply device A is increased in at least one of the thickness direction of the base20and the direction in which the solar cell panel50is inserted into and removed from the base20.

In the second embodiment, the entire solar cell panel50is accommodated in the base20in the retracted position. Therefore, in the retracted position, the size of the entire photovoltaic power supply device A is reduced in both the direction in which the solar cell panel50is inserted into and removed from the base20and the thickness direction of the base20, as compared with the use position, in which the solar cell panel50is located outside the base20.

(2-3) The friction generated between the shafts85and the inner wall surfaces93aof the grooves93is set to be large enough to allow for adjustment of the angle of the solar cell panel50with respect to the base20. Therefore, similarly to advantage of item (1-6), when the solar cell panel50is in the use position, the tilt angle of the solar cell panel50with respect to the base20can be adjusted by varying the magnitude of the external force applied to the solar cell panel50, and the solar cell panel50can be maintained at the adjusted tilt angle.

(2-4) In the thin-film solar cell51shown inFIG.5, the base member61and a member located between the base member61and the power generation layer66are made of a material that is transmissive to light. In addition, the base member75and the member located between the base member75and the power generation layer66are made of a material that is transmissive to light. Therefore, in a case in which the light receiving surface56of any of the base members61,75is irradiated with light, that is, in a case in which the light receiving surface56is directed to the light source LS, the power generation layer66is capable of generating power.

The above-described embodiments may be modified as follows. The above-described embodiments and the following modifications can be combined as long as the combined modifications remain technically consistent with each other.

Modifications to First and Second Embodiments

In the first and second embodiments, the positive electrode62is stacked on the single base member61together with the negative electrode63as shown inFIG.5. However, only the negative electrode63may be stacked on the base member61, and the positive electrode62may be stacked on the base member75. That is, the negative electrode63and the positive electrode62may be stacked on different base members61,75.

In this case, the negative electrode63is disposed between the base member61and the electron transport layer68. The positive electrode62is disposed between the base member75and the hole transport layer67. The positive electrode71is omitted.

The base surface of the base20may be formed by at least a part of the front surface32,37. Thus, the entire front surface32,37may be a base surface, or only a part of the front surface32,37may be a base surface.

In a case in which the light receiving surface56is provided on the outer surface of the solar cell panel50, which is on at least one side in the thickness direction, the light receiving surface56may be provided on part of or the entirety of the outer surface.

As a structure for detachably attaching the photovoltaic power supply device A to the mobile terminal10, an attachment structure different from that used in the first and second embodiments (attraction by a magnet) may be employed.

InFIG.10, the power transmitting unit43of the photovoltaic power supply device A may be connected to the mobile terminal10by a cable or the like. Power generated by the solar cell panel50may be stored in the power storage unit42in the base20, and the power may be supplied to the mobile terminal10by the power transmitting unit43via a cable or the like.

Modifications to First Embodiment

During power generation by the solar cell panel50, there may be situations where no issues arise even if image capturing by the camera is obstructed by the solar cell panel50In this case, the base20may be attached to the mobile terminal10in a state in which the base20overlaps with the lens12inFIG.2and the like.

InFIGS.3and4, the shaft82may be inserted into the shaft receiving hole27in a non-removable manner. Further, the terminal portion84may be inserted into the connection hole29in a non-removable manner. However, in this case, it is difficult to remove the solar cell panel50from the base20.

Unlike the first embodiment, the connectable portion in the base20may include the terminal portion84, and the connection portion in the solar cell panel50may include the connection hole29. In this case, the terminal portion84is inserted into the connection hole29as the shaft82is inserted into the shaft receiving hole27.

Unlike the first embodiment, the shaft82may be provided on the base20, and the shaft receiving portion26having the shaft receiving hole27may be provided on the solar cell panel50. In this case, similarly to the first embodiment, the connectable portion in the base20may include the connection hole29, and the connection portion in the solar cell panel50may include the terminal portion84. In addition, unlike the first embodiment, the connectable portion in the base20may include the terminal portion84, and the connection portion in the solar cell panel50may include the connection hole29. In either case, the terminal portion84is inserted into the connection hole29as the shaft82is inserted into the shaft receiving hole27.

The shaft receiving hole27inFIG.7and other drawings may either extend through the shaft receiving portion26or not. Similarly, the connection hole29may extend through the protrusion28or not.

FIGS.14and15illustrate a modification of the support structure SS, in which part or the entirety the protrusion81may be formed by a motor101having a rotary shaft102extending in the direction along the first axis AL1. In this case, the motor101is fixed to the solar cell panel50. The rotary shaft102is removably inserted into the shaft receiving hole27. In a state in which the rotary shaft102is inserted into the shaft receiving hole27, the rotary shaft102is coupled to the shaft receiving hole27so as to be integrally rotatable with the shaft receiving hole27.

For example, an external gear103having multiple external teeth104extending along the first axis AL1is attached to the rotary shaft102so as to be integrally rotatable with the rotary shaft102. The rotary shaft102and the external gear103form the shaft82. The shaft receiving portion26is formed by an internal gear105having multiple internal teeth106extending along the first axis AL1in the shaft receiving hole27.

The external teeth104of the external gear103are meshed with the internal teeth106of the internal gear105, so that the shaft82and the shaft receiving hole27are coupled to each other to rotate integrally. The internal teeth106are not shown inFIG.14

Since the external teeth104and the internal teeth106extend along the first axis AL1, the external gear103and the internal gear105can be coupled to each other or disconnected from each other by moving the gears103and105relative to each other in a direction along the first axis AL1. The shaft82is inserted into the shaft receiving hole27by moving the external gear103and the internal gear105toward each other along the first axis AL1. When the external teeth104and the internal teeth106are meshed with each other by the insertion, the shaft82is coupled to the shaft receiving hole27so as to be integrally rotatable. From this coupled state, the external gear103and the internal gear105are moved away from each other along the first axis AL1, so that the shaft82is removed from the shaft receiving hole27. When the external gear103and the internal gear105are no loner meshed each other by the removal, the shaft82is disconnected from the shaft receiving hole27.

According to this modification, when the rotary shaft102of the motor101rotates, the rotation is transmitted to the shaft receiving hole27via the external teeth104of the external gear103and the internal teeth106of the internal gear105. By the transmission of the rotation, the solar cell panel50is tilted about the shaft82with respect to the base20. This allows the tilt angle of the solar cell panel50with respect to the base20to be adjusted by tilting the solar cell panel50so that the light receiving surface56faces the light source LS without applying an external force to the solar cell panel50with the hand HA or the like.

In addition, when the shaft82is removed from the shaft receiving hole27, the solar cell panel50is no longer supported by the base20with the shaft82and the shaft receiving hole27. When the shaft82is inserted into the shaft receiving hole27, the solar cell panel50is supported by the base20with the shaft82and the shaft receiving hole27. Therefore, also in this modification, it is possible to repair and replace the malfunctioning solar cell panel50, and to change the solar cell panel50for design change.

In contrast to the modification ofFIGS.14and15, the base20may be provided with the motor101having the rotary shaft102, to which the external gear103is attached to be integrally rotatable. The internal gear105including the internal teeth106in the shaft receiving hole27may be provided in the solar cell panel50.

In order to couple the rotary shaft102of the motor101in the modification ofFIGS.14and15to the shaft receiving hole27such that the rotary shaft102and the shaft receiving hole27are integrally rotatable without using the external gear103, the rotary shaft102and the shaft receiving hole27may be coupled to each other by spline-engagement. In this case, external teeth are formed on the outer circumferential surface of the rotary shaft102, and internal teeth are formed on the inner wall surface of the shaft receiving hole27. The shaft82includes the rotary shaft102having external teeth on its outer circumferential surface.

InFIG.10, power may be supplied from the solar cell panel50to the power receiving unit41by contactless power supply.

The tilting direction of the solar cell panel50with respect to the base20may be changed to a direction different from that in the first embodiment.FIG.16shows a modification. In this modification, the first functional portion21and the second functional portion31are adjacent to each other in the width direction (lateral direction inFIG.16) instead of the length direction of the base20.

A protrusion81having a shaft and a shaft receiving portion26having a shaft receiving hole are arranged in the length direction. The axis of the shaft and the shaft receiving hole extends in the length direction. The direction in which the axis extends is a direction orthogonal to the direction in which the first axis AL1and the second axis AL2extend in the first embodiment. The solar cell panel50is supported by the shaft inserted into the shaft receiving hole so as to be tiltable in a direction indicated by the arrow inFIG.16.

In this case as well, the position of the solar cell panel50with respect to the base20can be changed by tilting the solar cell panel50. The entirety of the solar cell panel50overlaps with the front surface32(base surface) from the outside of the base20, and thus the solar cell panel50is in a retracted position (not shown). In addition, when the solar cell panel50is brought into the use position, the solar cell panel50does not overlap with the front surface32(base surface) outside the base20, and is tiltable the axis.

Therefore, by bringing the solar cell panel50into the use position, the user can hold the photovoltaic power supply device A together with the mobile terminal10without holding the solar cell panel50as shown inFIG.16. It is possible to prevent the irradiation of light to the light receiving surface from being largely blocked by the hand HA, and thus reduce the decrease in the power generation efficiency of the solar cell panel50.

In addition, in the use position, the solar cell panel50is tilted about the shaft to direct the light receiving surface toward the light source. This allows the light receiving surface to be irradiated with more light and thus increases the power generation efficiency of the solar cell panel50.

As shown inFIG.16, a protrusion83having a terminal portion and a protrusion28having a connection hole may be arranged in the length direction. In this case as well, the solar cell panel50can be electrically connected to the base20by inserting the terminal portion into the connection hole in a contact state.

InFIGS.3and7, multiple combinations of the protrusion81having the shaft82and the shaft receiving portion26having the shaft receiving hole27may be provided.

InFIG.5, the thin-film solar cell51according to the second embodiment, in which each base member61,75has the light receiving surface56, may be used as the thin-film solar cell51of the solar cell panel50according to the first embodiment.

The relay structure RS may be implemented by a structure different from that of the first embodiment, in which the terminal portion84is inserted into the connection hole29in a contact state. In this case, the relay structure RS may be provided at a position different from the position on the second axis AL2.

Modifications to Second Embodiment

During power generation by the solar cell panel50, there may be situations where no issues arise even if image capturing by the camera is obstructed by the solar cell panel50Therefore, when the solar cell panel50is switched from the retracted position to the use position, the solar cell panel50in the accommodating portion91may be slid in a direction approaching the lens12along the length of the base20as indicated by the solid lines inFIG.17.

In this case, as shown inFIG.17, the solar cell panel50is tilted about the shafts85in a state in which the base20is held together with the mobile terminal10. This tilting action directs the light receiving surface56toward the light source LS, as indicated by the solid lines inFIG.17, so as to increase the power generation efficiency of the solar cell panel50. In addition, the solar cell panel50may be tilted in correspondence with the position of the light source LS so that the light receiving surface56is directed toward the light source LS. The solar cell panel50indicated by the long-dash double-short-dash lines inFIG.17is an example of the tilted solar cell panel50.

As in the modification of the first embodiment shown inFIG.16, the tilting direction of the solar cell panel50with respect to the base20may be changed to a direction different from that in the second embodiment. For example, the solar cell panel50in the retracted position may be moved in the width direction of the base20to be in the use position. In the use position, a portion supported that is by the base20with the shaft85remains in the accommodating portion91, and a portion different from the supported portion is removed to the outside in the width direction of the base20. The light receiving surface56is directed to the light source LS by tilting the solar cell panel50about the shaft85extending in the length direction.

InFIGS.12,13, and17, in the base20, at least one of the side portions on the opposite sides of the accommodating portion91in the thickness direction may be made of a transparent or translucent material that is transmissive to light. With this modification, it is possible to irradiate the light receiving surface56with light even when the solar cell panel50is in the retracted position. The solar cell panel50can generate power even in the retracted position.

A structure different from that of the second embodiment may be employed as a structure in which surfaces on the opposite sides in the thickness direction of the solar cell panel50include the light receiving surfaces56.FIG.18shows such a modification. In the first embodiment, the single thin-film solar cell51is used as the solar cell panel50as shown inFIG.5. The light receiving surface56of the thin-film solar cell51according to the first embodiment is an outer surface that is on one side in the thickness direction of the thin-film solar cell51.

In contrast, the solar cell panel50of the modification shown inFIG.18includes two thin-film solar cells51having the same structure as the thin-film solar cell in the first embodiment. Specifically, the two thin-film solar cells51of the solar cell panel50of the modification each include, as the light receiving surface56, an outer surface that is on one side in the thickness direction of the thin-film solar cell51.

The two thin-film solar cells51of the modification are disposed back to back such that the light receiving surfaces56form surfaces on the opposite sides in the thickness direction of the solar cell panel50. That is, the two thin-film solar cells51are arranged such that the base members75are adjacent to each other.

With this modification, even if the light from the light source LS is radiated on the solar cell panel50from any side in the thickness direction, the thin-film solar cell51on the irradiated side generates power. Therefore, even when any of the light receiving surfaces56is directed toward the light source LS, it is possible to generate power.

The configuration of this modification may be employed in the solar cell panel50according to the first embodiment.

In the second embodiment, the shaft85may be removably engaged with the groove93or may be unremovably engaged with the groove93. In the former case, the solar cell panel50can be attached to and detached from the base20. The same advantage as the advantage of item (1-3) of the first embodiment is achieved. Specifically, it is possible to repair and replace the solar cell panel50when the solar cell panel50malfunctions, and to replace the solar cell panel50with a solar cell panel having a different design.

The thin-film solar cell51according to the first embodiment, which has the light receiving surface56on only one of the base members61and75, may be used as the solar cell panel50according to the second embodiment.

Other Modifications

The electronic device may be changed to an electronic device different from the mobile terminal10as long as the electronic device is small enough to be held in a state in which the photovoltaic power supply device A is attached and operates by being supplied with power generated by the photovoltaic power supply device A.

For example, the electronic device may be a wearable device. A wearable device is worn on a living body (e.g., a human body), and is typically a wearable terminal (e.g., a smart watch or smart glasses).

The power supplied from the power transmitting unit43of the photovoltaic power supply device A shown inFIG.10to the electronic device may be used for a purpose different from power storage by the power storage unit11of the electronic device. The power may be used, for example, to cause the electronic device to perform functions of the main body. Further, in a case in which the electronic device includes an electric product, such as a cooling fan, which exhibits a function not directly related to the original function of the electronic device, the power may be used for the operation of the electric product.