Light receiving device, power supply system, and power supply method

Abstract

This power supply system provides a power supply system that can suppress fluctuations in the power obtained from the entire photoelectric conversion cell even if the irradiation position of the excitation light is slightly shifted. [Solution] The power supply system includes a light-emitting device 100 that emits excitation light, and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-receiving device 200 has a plurality of photoelectric conversion cells 220. The power supply system is configured so that excitation light, separated to correspond to each of the photoelectric conversion cells 220, reaches the plurality of photoelectric conversion cells 220.

Description

[Technical Field]

[0001] The present invention relates to a light receiving device, a power supply system, and a power supply method. [Background technology]

[0002] For example, a power supply method is known in which power is supplied to a photoelectric conversion element equipped on a moving object such as an aircraft by irradiating it with excitation light such as laser light (see Patent Document 1 and Non-Patent Document 1 below). Wireless power supply using laser light enables long-distance power transmission and is attracting attention as a new energy transfer technology. In Patent Document 1 and Non-Patent Document 1, the photoelectric conversion element that receives the excitation light has a plurality of photoelectric conversion cells that are electrically connected to each other in series and / or in parallel. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-157026 [Non-patent literature]

[0004] [Non-Patent Document 1] F. Steinsiek, et., al., “Wireless Power Transmission Experiment using an airship as relay system and a moveable rover as ground target for later planetary exploration missions”, In Proceedings of the 8th ESA Workshop on Advanced Space Technologies for Robotics and Automation 'ASTRA 2004' ESTEC, Noordwijk, The Netherlands, November 2-4, 2004 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] As mentioned above, photoelectric conversion elements that receive excitation light typically have multiple photoelectric conversion cells. A photoelectric conversion cell corresponds to a unit of region where photoelectric conversion takes place. In Patent Document 1 and Non-Patent Document 1, a single excitation light is irradiated across the entirety of multiple photoelectric conversion cells.

[0006] In this process, it is desirable that the excitation light irradiates each of the multiple photoelectric conversion cells in a uniform manner. However, if the distance between the excitation light source and the photoelectric conversion element on the receiving side is large, the irradiation position of the excitation light may shift from the reference position. As a result, the irradiation area of ​​the excitation light irradiated onto each photoelectric conversion cell may change for each cell, and the energy that each photoelectric conversion cell receives from the excitation light may change. Consequently, variations occur in the voltage and / or current values ​​generated in each photoelectric conversion cell.

[0007] Multiple photoelectric conversion cells are electrically connected to each other in series and / or parallel. If the voltage and / or current values ​​in one of the photoelectric conversion cells decrease, the total power obtained from the multiple photoelectric conversion cells decreases. For example, if multiple photoelectric conversion cells are electrically connected in series, the current value generated in each of the multiple photoelectric conversion cells will be limited by the lowest value among them. As a result, the current value generated in each of the multiple photoelectric conversion cells decreases, and consequently, the total power obtained from the multiple photoelectric conversion cells decreases as well. Even if multiple photoelectric conversion cells are electrically connected in parallel, if the voltage generated in one of the multiple photoelectric conversion cells decreases, the total power obtained from the multiple photoelectric conversion cells also decreases.

[0008] Thus, a shift in the irradiation position of the excitation light causes fluctuations in the power obtained from the entire photoelectric conversion cell. Therefore, a light receiving device, power supply system, and power supply method are desired that can suppress fluctuations in the power obtained from the entire photoelectric conversion cell even if the irradiation position of the excitation light is slightly shifted. [Means for solving the problem]

[0009] A power supply system according to one embodiment includes a light-emitting device that emits excitation light and a light-receiving device that receives the excitation light emitted from the light-emitting device. The light-receiving device has a plurality of photoelectric conversion cells. The power supply system is configured such that excitation light, separated to correspond to each of the photoelectric conversion cells, reaches the plurality of photoelectric conversion cells.

[0010] A light-receiving device according to one embodiment includes a plurality of photoelectric conversion cells that receive excitation light, and an optical element. The optical element is configured to separate the excitation light passing through the optical element into a plurality of parts, and to direct each of the separated excitation light parts to the corresponding plurality of photoelectric conversion cells.

[0011] A power supply method according to one embodiment includes the step of emitting excitation light from a light-emitting device and causing the excitation light, separated to correspond to each of the multiple photoelectric conversion cells provided in a light-receiving device, to reach the multiple photoelectric conversion cells. [Effects of the Invention]

[0012] According to the above embodiment, it is possible to provide a light receiving device, a power supply system, and a power supply method that can suppress fluctuations in the power obtained from the entire photoelectric conversion cell even if the irradiation position of the excitation light is slightly shifted. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram of the power supply system according to the first embodiment. [Figure 2] Figure 2 is a schematic plan view of a light receiving device provided in the power supply system according to the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view of the light receiving device along the line 3A-3A in Figure 2. [Figure 4] Figure 4 is a schematic diagram showing the configuration of a light-emitting device and a light-receiving device provided in the power supply system according to the first embodiment. [Figure 5]FIG. 5 is a diagram showing an example of an irradiation area of excitation light irradiated at a reference position in the power supply system according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the intensity of excitation light and the irradiation area. [Figure 7] FIG. 7 is a diagram showing an example of an irradiation area of excitation light irradiated at a position slightly deviated from the reference position in the power supply system according to the first embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the configuration of a light emitting device and a light receiving device provided in the power supply system according to the second embodiment. [Figure 9] FIG. 9 is a schematic diagram showing the configuration of a light emitting device and a light receiving device provided in the power supply system according to the third embodiment. [Figure 10] FIG. 10 is a diagram showing an example of an irradiation area of excitation light irradiated at a reference position in the power supply system according to the third embodiment. [Figure 11] FIG. 11 is a schematic diagram showing the configuration of a light emitting device and a light receiving device provided in the power supply system according to the fourth embodiment. [Figure 12] FIG. 12 is a schematic plan view of an optical element provided in the power supply system according to the fourth embodiment. [Figure 13] FIG. 13 is a schematic diagram showing the configuration of a light emitting device and a light receiving device provided in the power supply system according to the fifth embodiment. [Figure 14] FIG. 14 is a diagram showing an example of an irradiation area of excitation light irradiated at a reference position in the power supply system according to the fifth embodiment. [Figure 15] FIG. 15 is a schematic plan view showing the configuration of a photoelectric conversion element of a light receiving device in the power supply system according to the sixth embodiment. [Figure 16] FIG. 16 is a schematic plan view for explaining the irradiation area of excitation light in the power supply system according to the experimental example. [Figure 17] FIG. 17 is a schematic plan view for explaining the irradiation area of excitation light in the power supply system according to the experimental example. [Figure 18]Figure 18 is a graph showing the experimental results of the photoelectric conversion efficiency η in experimental examples 1 to 3. [Figure 19] Figure 19 is a schematic plan view illustrating the irradiation area of ​​the excitation light in a power supply system according to a reference example. [Figure 20] Figure 20 is a graph showing the experimental results of the photoelectric conversion efficiency η in a reference example. [Modes for carrying out the invention]

[0014] The embodiments will be described below with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the proportions of the dimensions, etc., may differ from those of reality.

[0015] [First Embodiment] A power supply system and power supply method according to the first embodiment will be described. Figure 1 is a schematic diagram of the power supply system according to the first embodiment. Figure 2 is a schematic plan view of the light receiving device provided in the power supply system according to the first embodiment. Figure 3 is a schematic cross-sectional view of the light receiving device along the line 3A-3A in Figure 2. Figure 4 is a schematic diagram showing the configuration of the light emitting device and light receiving device provided in the power supply system according to the first embodiment. Figure 5 is a diagram showing an example of the irradiation area of ​​the excitation light irradiated to the reference position in the power supply system according to the first embodiment.

[0016] The power supply system may include a first device 10 and a second device 20. The first device 10 may have a light-emitting device 100 that emits excitation light. The second device 20 may have a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The first device 10 and the second device 20 may be located at different distances from each other.

[0017] The relative positions of the light-emitting device 100 and the light-receiving device 200 may be configured to be variable. For example, at least one of the first device 10 and the second device 20 may be a mobile body. If at least one of the first device 10 and the second device 20 is a mobile body, the relative positions of the light-emitting device 100 and the light-receiving device 200 become variable. The mobile body may be, for example, a car, a ship, or an aircraft. The aircraft includes, for example, a drone, an aircraft, or a rocket. The aircraft may be one that travels at high altitudes, such as in the stratosphere.

[0018] Both the first device 10 and the second device 20 may be mobile. Alternatively, one of the first device 10 and the second device 20 may be mobile, and the other may be stationary. The stationary device may be, for example, a device fixed to real estate such as a building or land.

[0019] The light-emitting device 100 emits excitation light toward the light-receiving device 200 provided on the second device 20. The light-emitting device 100 may be configured to adjust the direction in which the excitation light is irradiated, depending on the positional relationship between the first device 10 and the second device 20.

[0020] The excitation light emitted from the light-emitting device 100 is preferably highly directional light. The excitation light may be, for example, laser light. The excitation light includes a wavelength range that can be converted into electrical energy in the light-receiving device 200, which will be described later. The wavelength range of the excitation light is not particularly limited. The wavelength range of the excitation light may be, for example, wavelengths in the infrared region.

[0021] When excitation light travels long distances through the atmosphere, it is preferable that the excitation light has a wavelength corresponding to the so-called "atmospheric window," which has high light transmittance in the atmosphere, in order to suppress the attenuation of the intensity of the excitation light. For example, the excitation light may have a wavelength of 1070 nm ± 100 nm.

[0022] The light receiving device 200 has a photoelectric conversion element 210. The photoelectric conversion element 210 is an element that converts excitation light emitted from the light-emitting device 100 into electrical energy. The electrical energy generated by the photoelectric conversion element 210 can be used, for example, by electronic equipment mounted on the second device 20.

[0023] The photoelectric conversion element 210 has a plurality of photoelectric conversion cells 220. Each photoelectric conversion cell 220 corresponds to a unit of area where photoelectric conversion is performed. In the embodiment shown in Figure 2, two photoelectric conversion cells 220 are shown. Alternatively, the photoelectric conversion element 210 may have three or more photoelectric conversion cells 220.

[0024] Multiple photoelectric conversion cells 220 may be arranged in a line or in a grid. The photoelectric conversion element 210 may have an integrated structure that includes multiple photoelectric conversion cells 220 integrated on a substrate, as described later. Multiple photoelectric conversion cells 220 may be electrically connected to each other in series and / or in parallel. In the embodiments shown in Figures 2 and 3, two photoelectric conversion cells 220 partially overlap each other, and the two photoelectric conversion cells 220 are electrically connected in the overlapping portion.

[0025] Each photoelectric conversion cell 220 may, although not required, have a conductive substrate 222 that serves as a base for forming each layer, such as the first electrode layer 224, which will be described later. The conductive substrate 222 may be made of a substrate such as a metal substrate. The conductive substrate 222 may be made of, for example, titanium (Ti), stainless steel (SUS), copper, aluminum, or an alloy thereof. Alternatively, the conductive substrate may be a laminated structure in which multiple metal substrates are stacked, for example, stainless steel foil, titanium foil, or molybdenum foil may be formed on the surface of the substrate. Instead, the photoelectric conversion cell 220 may have a glass substrate as the base for forming each layer, such as the first electrode layer 224, which will be described later.

[0026] The two photoelectric conversion cells 220 may be electrically connected by a conductor 250. In Figure 3, the conductor 250 is provided between the surface of one of the two adjacent photoelectric conversion cells 220 and the back surface of the other photoelectric conversion cell 220. In this way, the conductor 250 electrically connects the two photoelectric conversion cells.

[0027] The photoelectric conversion element 210 may have a pair of electrodes 260 for extracting power obtained from a plurality of photoelectric conversion cells 220. One of the pair of electrodes 260 is connected to the front side of one of two adjacent photoelectric conversion cells 220. The other of the pair of electrodes 260 is connected to a conductive substrate 222 on the back side of the other of the two adjacent photoelectric conversion cells 220.

[0028] Each photoelectric conversion cell 220 may be a so-called silicon-based, compound-based, or organic-based photoelectric conversion cell. Examples of silicon-based photoelectric conversion cells include crystalline silicon-based or amorphous silicon-based photoelectric conversion cells. Examples of compound-based photoelectric conversion cells include CIS-based or CGIS-based photoelectric conversion cells. Examples of organic-based photoelectric conversion cells include dye-sensitized, perovskite-based, or organic semiconductor-based photoelectric conversion cells. The photoelectric conversion cell 220 is not limited to these and may be any photoelectric conversion cell.

[0029] The configuration of the photoelectric conversion cell 220 is not particularly limited. However, it is desirable that the multiple photoelectric conversion cells 220 have the same type and configuration as the others. This ensures that the photoelectric conversion characteristics of the multiple photoelectric conversion cells 220 are substantially the same as those of the others.

[0030] Referring to Figure 3, an example of a stacked structure of a CIS-based photoelectric conversion cell will be described. The photoelectric conversion cell 220 may include a conductive substrate 222, a first electrode layer 224 on the conductive substrate 222, a photoelectric conversion layer 226 on the first electrode layer 224, and a second electrode layer 228 on the photoelectric conversion layer 226.

[0031] The first electrode layer 224 may contain, for example, at least one transition metal material selected from the group consisting of molybdenum (Mo), tungsten (W), titanium (Ti), vanadium (V), chromium (Cr), niobium (Nb), and tantalum (Ta).

[0032] The second electrode layer 228 may be composed of a transparent electrode layer. When the second electrode layer 228 is composed of a transparent electrode layer, the excitation light incident on the photoelectric conversion layer 226 passes through the second electrode layer 228.

[0033] The second electrode layer 228 may contain at least one selected from the group consisting of, for example, indium tin oxide (In2O3:Sn), indium titanium oxide (In2O3:Ti), indium zinc oxide (In2O3:Zn), tin-zinc doped indium oxide (In2O3:Sn,Zn), tungsten-doped indium oxide (In2O3:W), hydrogen-doped indium oxide (In2O3:H), indium gallium zinc oxide (InGaZnO4), zinc tin oxide (ZnO:Sn), fluorine-doped tin oxide (SnO2:F), gallium-doped zinc oxide (ZnO:Ga), boron-doped zinc oxide (ZnO:B), and aluminum-doped zinc oxide (ZnO:Al).

[0034] In each photoelectric conversion cell 220, the photoelectric conversion layer 226 is provided between the first electrode layer 224 and the second electrode layer 228 in the thickness direction (stacking direction). The photoelectric conversion layer 226 is sometimes called a light absorption layer.

[0035] In a specific example of a CIGS-type photoelectric conversion cell, the photoelectric conversion layer 226 is composed of a chalcogen semiconductor containing chalcogen elements and functions as a polycrystalline or microcrystalline p-type compound semiconductor layer. The photoelectric conversion layer 226 is composed of a chalcopyrite-structured I-III-VI2 compound semiconductor containing, for example, group I elements, group III elements, and group VI elements (chalcogen elements). Here, the group I elements can be selected from copper (Cu), silver (Ag), gold (Au), etc. The group III elements can be selected from indium (In), gallium (Ga), aluminum (Al), etc. In addition, the photoelectric conversion layers 26a and 26b may contain tellurium (Te) as a group VI element, in addition to selenium (Se) and sulfur (S).

[0036] Alternatively, the photoelectric conversion layer 226 may be composed of an I2-(II-IV)-VI4 group compound semiconductor, which is a CZTS-based chalcogen semiconductor containing Cu, Zn, Sn, S, or Se. Typical examples of CZTS-based chalcogen semiconductors include those using compounds such as Cu2ZnSnSe4 and Cu2ZnSn(S,Se)4.

[0037] The photoelectric conversion layer 226 is not limited to those described above, and may be composed of any material that causes photoelectric conversion.

[0038] The photoelectric conversion cell 220 is not limited to the above embodiment and may have a configuration depending on the type of photoelectric conversion element. For example, in the case of a silicon-based photoelectric conversion cell, the photoelectric conversion cell 220 may include an n-type semiconductor (n-type silicon) and a p-type semiconductor (p-type silicon). Alternatively, the photoelectric conversion cell 220 may include i-type silicon between the n-type semiconductor and the p-type semiconductor. Alternatively, the photoelectric conversion cell 220 may include a III-V compound semiconductor. The III-V compound semiconductor may include at least one from the group including, for example, GaAs, InGaAsP, InGaAs, InGaP, and GaSb.

[0039] Each photoelectric conversion cell 220 may optionally be provided with a current collecting electrode 230 on the second electrode layer 228. The current collecting electrode 230 collects charge carriers from the second electrode layer 228 and is formed of a conductive material. The current collecting electrode 228 may be in direct contact with the second electrode layer 228.

[0040] In the illustrated embodiment, the current collector electrode 230 is provided near the end of each photoelectric conversion cell 220 in the direction in which the two photoelectric conversion cells 220 are aligned. The current collector electrode 230 may extend along a direction intersecting the direction in which the two photoelectric conversion cells 220 are aligned. In the illustrated embodiment, one of the pair of electrodes 260 is connected to the current collector electrode 230 on the surface side of one of the two adjacent photoelectric conversion cells 220. Alternatively, the electrode 260 may be connected to the first electrode layer 228.

[0041] Each photoelectric conversion cell 220 has a region R1 that contributes to photoelectric conversion (power generation region) when viewed from a direction perpendicular to the light-receiving surface that receives excitation light. The region other than the power generation region R1 is a region that does not contribute to photoelectric conversion (non-power generation region) R2. The energy of the excitation light irradiated into the power generation region R1 is converted into electrical energy in the photoelectric conversion cell 220. The energy of the excitation light irradiated into the non-power generation region R2 is not converted into electrical energy in the photoelectric conversion cell 220. In the illustrated embodiment, the region of each photoelectric conversion cell 220 that overlaps with the current-collecting electrode 230 when viewed from a direction perpendicular to the light-receiving surface corresponds to the non-power generation region R2.

[0042] The power generation region R1 may be provided over a wide area within the photoelectric conversion cell 220 on the light-receiving surface. Preferably, the power generation region R1 may be provided over an area within the light-receiving surface that excludes the edges of the photoelectric conversion cell 220. In particular, at least a portion of the non-power generation region R2 may be located between the power generation regions R1 of adjacent photoelectric conversion cells 220 (see Figure 2). In this case, the power generation regions R1 of adjacent photoelectric conversion cells 220 are not connected to each other.

[0043] The power supply system is configured so that excitation light, separated to correspond to each of the photoelectric conversion cells 220, reaches multiple photoelectric conversion cells 220 (see Figures 4 and 5). In the figures, the irradiation area of ​​the excitation light is indicated by the symbol S.

[0044] In the first embodiment, the light-emitting device 100 may include a light source 110 that emits excitation light, and an optical element 300 that separates the excitation light emitted from the light source 110 into a plurality of excitation beams. The optical element 300 may include, for example, a diffraction-type beam splitter.

[0045] As a result, the excitation light emitted from the light source 110 is split into multiple excitation light beams by the optical element 300. Each of the split excitation light beams reaches each of the photoelectric conversion cells 220 of the photoelectric conversion element 210. That is, each of the photoelectric conversion cells 220 is configured to receive the multiple split excitation light beams. In the first embodiment, one of the split excitation light beams is irradiated onto one photoelectric conversion cell 220. In other words, there is one irradiation area S of one excitation light beam on one photoelectric conversion cell 220.

[0046] Figure 6 shows the relationship between the intensity of the excitation light and the irradiation area. Figure 6 shows the relationship between the intensity of the excitation light reaching the photoelectric conversion cell 220 and the irradiation area S. The vertical axis in Figure 6 represents the intensity of the excitation light. The irradiation area S of the excitation light is 1 / e of the peak intensity of the excitation light on the photoelectric conversion cell 220. 2 This is defined by a range of excitation light intensities that are more than twice the normal range, where "e" is Napier's number. In Figure 6, the excitation light intensity has two peaks. The positions of these intensity peaks correspond to the positions of the two photoelectric conversion cells 220.

[0047] In this specification, “separated excitation light” is defined as the peak intensity of the excitation light on the surface of the multiple photoelectric conversion cells 220, as shown in Figure 6, at 1 / e 2This means that multiple ranges with excitation light intensities ranging from more than twice the original range are separated. Note that the light intensity at the positions between the multiple excitation light peaks does not necessarily have to be zero. In this embodiment, each of these separated excitation lights is irradiated onto each of the corresponding photoelectric conversion cells 220.

[0048] As shown in Figure 5, it is preferable that the power supply system is configured such that the irradiation area S of the excitation light irradiated onto each photoelectric conversion cell 220 is smaller than the power generation area R1 of each photoelectric conversion cell 220. This ensures that each divided excitation light, when irradiated onto a reference position, remains within the power generation area R1 of each photoelectric conversion cell 220 and does not extend into the non-power generation area R2. Here, the "reference position" is the reference position (ideal position in design) to which the excitation light should be irradiated, meaning an irradiation position without deviation. In Figure 5, the center of the reference position is indicated by the symbol "RC", and the center of each irradiation area S coincides with the center RC of the corresponding reference position.

[0049] Figure 7 shows an example of the irradiation area of ​​excitation light irradiated at a position slightly offset from the reference position in the power supply system according to the first embodiment. As shown in Figure 7, even if the irradiation area S of the excitation light is slightly offset from the reference position RC on the photoelectric conversion cell 220, the irradiation area S of the excitation light remains within the power generation region R1 on each photoelectric conversion cell 220 and does not extend into the non-power generation region R2. Therefore, even if the irradiation area S of the excitation light is slightly offset from the reference position RC on the photoelectric conversion cell 220, the voltage and current values ​​generated in each photoelectric conversion cell 220 do not decrease, and fluctuations in the power obtained from the photoelectric conversion cell 220 as a whole are suppressed.

[0050] Preferably, the power supply system is configured such that the irradiation area of ​​the excitation light irradiated onto each photoelectric conversion cell 220 (area of ​​irradiation area S) is 5% or more and 90% or less of the area of ​​the power generation region R1 of the photoelectric conversion cell 220. More preferably, the system is configured such that the irradiation area of ​​the excitation light irradiated onto each photoelectric conversion cell 220 is 10% or more and 80% or less of the area of ​​the power generation region R1 of the photoelectric conversion cell 220. More preferably, the system is configured such that the irradiation area of ​​the excitation light irradiated onto each photoelectric conversion cell 220 is 20% or more and 80% or less of the area of ​​the power generation region R1 of the photoelectric conversion cell 220. Even more preferably, the system is configured such that the irradiation area of ​​the excitation light irradiated onto each photoelectric conversion cell 220 is 30% or more and 70% or less of the area of ​​the power generation region R1 of the photoelectric conversion cell 220.

[0051] The smaller the area of ​​the excitation light irradiation area S is relative to the area of ​​the power generation region R1, the more the fluctuation in power obtained from the entire photoelectric conversion cell 220 is suppressed, even if the deviation between the excitation light irradiation area S and the reference position RC becomes larger.

[0052] On the other hand, by ensuring that the area of ​​the excitation light irradiation area S is 5% or more of the area of ​​the power generation region R1 of the photoelectric conversion cell 220, it is possible to prevent the total amount of power obtained from the photoelectric conversion cell 220 from becoming too small. In particular, if the irradiation area of ​​the excitation light irradiated to each photoelectric conversion cell 220 is 30% or more of the area of ​​the power generation region R1 of the photoelectric conversion cell 220, the amount of power generated can be increased from the viewpoint of photoelectric conversion efficiency.

[0053] The coefficient of variation CV, obtained by dividing the standard deviation σ of the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell 220 by the average value μ of the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell 220, may be, for example, 0.7 or less, preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.2 or less.

[0054] Here, N is the number of photoelectric conversion cells 220, and S is the irradiation area of ​​the excitation light irradiated onto the nth photoelectric conversion cell 220. nWhen expressed as such, the average value μ of the excitation light irradiation area is “μ = (S1 + S2 + ··· + S N ) / N”. Also, the standard deviation σ of the excitation light irradiation area is “σ = {((S1 - μ) 2 + (S2 - μ) 2 + ··· + (S N - μ) 2 ) / N} 1 / 2 ”.

[0055] The above coefficient of variation CV is expressed as “CV = σ / μ”. The coefficient of variation CV is an index representing the variation in the values of the excitation light irradiation area S. Therefore, the smaller the coefficient of variation CV, the smaller the variation in the excitation light irradiation area S irradiated to each photoelectric conversion cell 220. Therefore, each photoelectric conversion cell 220 generates substantially the same amount of current / voltage by receiving the excitation light.

[0056] Particularly, when the coefficient of variation CV regarding the values of the excitation light irradiation area is small as described above, it is more preferable that the plurality of photoelectric conversion cells 220 have the same type and configuration as each other. As a result, the photoelectric conversion characteristics of the plurality of photoelectric conversion cells 220 become substantially the same as each other, so each photoelectric conversion cell 220 generates the same amount of current / voltage by receiving the excitation light. Therefore, it is possible to reduce the possibility that the amount of electric power obtained as a whole for the photoelectric conversion cells 220 is limited by one photoelectric conversion cell 220 having a low generated value of voltage or current.

[0057] The power supply method according to the first embodiment can be implemented using the above power supply system. The power supply method includes a step of emitting excitation light from the light emitting device 100 and causing the separated excitation light corresponding to each of the plurality of photoelectric conversion cells 220 provided in the light receiving device 200 to reach the plurality of photoelectric conversion cells 220.

[0058] The method for separating the excitation light, the excitation light irradiation area S, the excitation light irradiation area, and the variation (coefficient of variation) of the excitation light irradiation area are as described above. As described above, the single excitation light emitted from the light source 110 is separated by an optical element 300 such as a diffractive beam splitter and irradiated onto each photoelectric conversion cell 220, so that the excitation light irradiates each photoelectric conversion cell 220 simultaneously.

[0059] The power supply system and power supply method may be configured to emit excitation light from the light-emitting device 100 while changing the relative positions of the light-emitting device 100 and the light-receiving device 200. Specifically, the above power supply method may be implemented while changing the relative positions of the first device 10 and the second device 20. This makes it possible to perform wireless power supply while moving the first device 10 and the second device 20.

[0060] In the first embodiment, the optical element 300 is provided on the light-emitting device 100. This allows the positional relationship between the light source 110 and the optical element 300 to be fixed. In this case, since the angle from the light source 110 to the optical element 300 is constant, the preparation and readjustment of the light source and the optical element 300 are simplified. In addition, since the incident angle of the excitation light from the light source 110 toward the optical element 300 is fixed, there is an advantage in that the intensity of each of the excitation light fractions divided by the optical element 300 is easily made uniform.

[0061] [Second Embodiment] A power supply system and power supply method according to the second embodiment will now be described. Figure 8 is a schematic diagram showing the configuration of a light-emitting device and a light-receiving device provided in the power supply system according to the second embodiment.

[0062] In the second embodiment, the same reference numerals are used for components similar to those in the first embodiment. Note that descriptions of components similar to those in the first embodiment may be omitted.

[0063] The power supply system according to the second embodiment may include, similar to the first embodiment, a light-emitting device 100 that emits excitation light and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-emitting device 100 may have a light source 110 that emits excitation light.

[0064] Furthermore, the power supply system may include an optical element 300 that separates the excitation light emitted from the light source 110 into multiple excitation beams. The optical element 300 may include, for example, a diffractive beam splitter, as in the first embodiment.

[0065] In the second embodiment, the optical element 300 is provided on the light receiving device 200. This allows the positional relationship between the multiple photoelectric conversion cells 220 and the optical element 300 to be fixed. Therefore, it is advantageous that the peak positions of each excitation light separated by the optical element 300 can be easily designed to match the reference position RC of the photoelectric conversion cell 220. In addition, since the incident angle of the divided excitation light from the optical element 300 toward the photoelectric conversion cell 220 is constant, it is easier to reduce variations in the power generation efficiency of each photoelectric conversion cell 220.

[0066] The configuration of the photoelectric conversion cell 220, the excitation light irradiation area S, the excitation light irradiation area, the relationship between the excitation light irradiation area and the power generation area of ​​the photoelectric conversion cell 220, and the variation (coefficient of variation) of the excitation light irradiation area are the same as in the first embodiment, so their explanations will be omitted.

[0067] The light receiving device 200 may have a base 280 to which a plurality of photoelectric conversion cells 220 are attached. In this case, the optical element 300 may be integrally provided on the base 280. In this case, the positional relationship between the plurality of photoelectric conversion cells 220 and the optical element 300 is fixed, so that each of the excitation light separated by the optical element 300 is more likely to irradiate each of the corresponding photoelectric conversion cells 220 as designed.

[0068] In the example shown in Figure 8, the base 280 has a bottom 282, a wall 284 rising from the bottom, and a mounting portion 286 projecting laterally from the wall 284. The optical element 300 is attached to the mounting portion 286. The optical element 300 may be attached to the mounting portion 286 by means of adhesive, for example. In this way, the optical element 300 may be integrally provided with the base 280. Note that the structure of the base 280 is not limited to the example shown in Figure 8 and can be modified in various ways.

[0069] In the above description, the optical element 300 is integrally mounted on the base 280. Alternatively, the optical element 300 may be detachable from the base 280. For example, if the mounting portion 286 of the base 280 has a shape that clamps the end of the optical element 300, the optical element 300 is fixed to the base 280 while attached to the mounting portion 286. In this case, the optical element 300 can be attached to and detached from the base 280 by sliding it relative to the base 280.

[0070] Thus, if the optical element 300 is detachable from the base 280, different types of optical elements can be used or not used as desired. Furthermore, if the optical element 300 deteriorates, it becomes easier to replace the optical element 300.

[0071] [Third Embodiment] A power supply system and power supply method according to the third embodiment will be described. Figure 9 is a schematic diagram showing the configuration of a light-emitting device and a light-receiving device provided in the power supply system according to the third embodiment. Figure 10 is a diagram showing an example of the irradiation area of ​​excitation light irradiated to a reference position in the power supply system according to the third embodiment.

[0072] In the third embodiment, components similar to those in the first embodiment are denoted by the same reference numerals. Note that the description of components similar to those in the first embodiment may be omitted.

[0073] The power supply system according to the third embodiment may include, similar to the first embodiment, a light-emitting device 100 that emits excitation light and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-emitting device 100 may have a light source 110 that emits excitation light. The power supply system may also have an optical element 300 that separates the excitation light emitted from the light source 110 into a plurality of excitation beams.

[0074] In the third embodiment, the light receiving device 200 has an optical mask 400. The optical mask 400 has a window 410 that shapes the excitation light irradiation area. The optical mask 400 is composed of a material that substantially prevents the excitation light from passing through, and the window 410 is the part that allows the excitation light to pass through. By appropriately designing the shape of the window 410, the shape of the excitation light irradiation area S irradiated onto the photoelectric conversion cell 220 can be appropriately determined. Therefore, the excitation light irradiation area S and the excitation light irradiation area can be easily determined by the shape and size of the window 410 of the optical mask 400.

[0075] Preferably, as shown in Figure 10, the power supply system is configured such that the shape of the irradiation area S of the excitation light irradiated onto each photoelectric conversion cell 220 is similar to the shape of the power generation region R1 of the photoelectric conversion cell 220. This suppresses fluctuations in the power obtained from the entire photoelectric conversion cell 220, regardless of the direction in which the irradiation area S of the excitation light is shifted with respect to the reference position RC. Furthermore, since the area of ​​the irradiation area S of the excitation light is made as large as possible, the amount of power obtained from the entire photoelectric conversion cell 220 can be made as large as possible.

[0076] In the example shown in Figure 9, the optical element 300 is provided in the light-emitting device 100. Alternatively, the optical element 300 may be provided in the light-receiving device 200.

[0077] In the example shown in Figure 9, the optical mask 400 is located on the light receiving device 200. In this case, the positional relationship between the optical mask 400 and the photoelectric conversion cell 220 can be fixed. Alternatively, the optical mask 400 may be located on the light emitting device 100. In this case, the positional relationship between the optical mask 400 and the light source 110 can be fixed.

[0078] The configuration of the photoelectric conversion cell 220, the irradiation area of ​​the excitation light, and the variation (coefficient of variation) of the irradiation area of ​​the excitation light are the same as in the first embodiment, so their explanation will be omitted.

[0079] [Fourth Embodiment] A power supply system and power supply method according to the fourth embodiment will now be described. Figure 11 is a schematic diagram showing the configuration of a light-emitting device and a light-receiving device provided in the power supply system according to the fourth embodiment. Figure 12 is a schematic plan view of an optical element provided in the power supply system according to the fourth embodiment.

[0080] In the fourth embodiment, the same reference numerals are used for components similar to those in the first embodiment. Note that descriptions of components similar to those in the first embodiment may be omitted.

[0081] The power supply system according to the fourth embodiment may include, similar to the first embodiment, a light-emitting device 100 that emits excitation light and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-emitting device 100 may have a light source 110 that emits excitation light. The power supply system may also have an optical element 300 that separates the excitation light emitted from the light source 110 into multiple excitation beams. Optionally, a lens system, such as a plano-concave lens 350, may be provided on the light source 110 side of the optical element 300.

[0082] In the fourth embodiment, the optical element 300 may be an optical mask having a plurality of windows 310 through which excitation light passes. The optical mask may have windows 310 corresponding to each of the plurality of photoelectric conversion cells 220, as shown in Figure 12. This ensures that even if the excitation light emitted from the light source 110 of the light-emitting device 100 has a single peak, the power supply system is configured, as in the first embodiment, to ensure that the excitation light, separated to correspond to each of the photoelectric conversion cells 220, reaches the plurality of photoelectric conversion cells 220.

[0083] In Figure 12, two rectangular windows 310 are formed. In this case, the irradiation area S of the excitation light irradiated onto the photoelectric conversion cell 220 is the same as in the state shown in Figure 10. The shape of the windows 310 formed on the optical mask as an optical element 300 can be appropriately designed based on the shape of the excitation light irradiation area S.

[0084] Preferably, the power supply system is configured such that the shape of the irradiation area S of the excitation light irradiated onto each photoelectric conversion cell 220 is similar to the shape of the power generation region R1 of the photoelectric conversion cell 220. Specifically, the shape of the window 310 formed in the optical mask as an optical element 300 may be formed to be similar to the shape of the power generation region R1. As a result, fluctuations in the power obtained from the entire photoelectric conversion cell 220 are suppressed regardless of the direction in which the irradiation area S of the excitation light is shifted with respect to the reference position RC. Furthermore, since the area of ​​the irradiation area S of the excitation light is made as large as possible, the amount of power obtained from the entire photoelectric conversion cell 220 can be made as large as possible.

[0085] In the example shown in Figure 11, the optical element 300 is located on the light receiving device 200. This allows the positional relationship between the optical element 300 and the photoelectric conversion cell 220 to be fixed. Alternatively, the optical element 300 may be located on the light emitting device 100. This allows the positional relationship between the optical element 300 and the light source 110 to be fixed.

[0086] The configuration of the photoelectric conversion cell 220, the irradiation area of ​​the excitation light, and the variation (coefficient of variation) of the irradiation area of ​​the excitation light are the same as in the first embodiment, so their explanation will be omitted.

[0087] [Fifth Embodiment] A power supply system and power supply method according to the fifth embodiment will now be described. Figure 13 is a schematic diagram showing the configuration of a light-emitting device and a light-receiving device provided in the power supply system according to the fifth embodiment. Figure 14 is a diagram showing an example of the irradiation area of ​​excitation light irradiated to a reference position in the power supply system according to the fifth embodiment.

[0088] In the fifth embodiment, the same reference numerals are used for components similar to those in the first embodiment. Note that descriptions of components similar to those in the first embodiment may be omitted.

[0089] The power supply system according to the fifth embodiment may include, similar to the first embodiment, a light-emitting device 100 that emits excitation light and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-emitting device 100 has a plurality of light sources 110 that emit excitation light.

[0090] In the fifth embodiment, each light source 110 may be provided in correspondence to each of the multiple photoelectric conversion cells 220. In the embodiment shown in Figure 13, two light sources 110 are provided in correspondence to one photoelectric conversion cell 220. Alternatively, one light source 110 may be provided in correspondence to one photoelectric conversion cell 220. Furthermore, three or more light sources 110 may be provided in correspondence to one photoelectric conversion cell 220.

[0091] The intensity distribution of excitation light emitted from multiple light sources may, as a whole, have multiple peaks, as shown in Figure 6, for example. That is, the excitation light emitted from the light-emitting device 100, which includes multiple light sources 110, can be described as "multiple separated excitation light." Therefore, in the fifth embodiment as well, the power supply system is configured so that the excitation light separated to correspond to each of the photoelectric conversion cells 220 reaches the multiple photoelectric conversion cells 220.

[0092] As shown in Figure 14, when multiple light sources 110 are provided corresponding to one photoelectric conversion cell 220, a large total area of ​​the excitation light irradiation area S can be secured. If the shape of the excitation light irradiation area is not formed with a material such as an optical mask, the shape of the excitation light irradiation area is usually circular or elliptical. As a result, the shape of the excitation light irradiation area S differs greatly from the shape of the power generation region R1 of the photoelectric conversion cell 220, and a large area of ​​the power generation region R1 may become wasted area that is not used. By forming multiple irradiation areas S in one photoelectric conversion cell 220 using multiple light sources 110, the power generation region R1 can be used as efficiently as possible. However, the excitation light irradiation area (total irradiation area) is smaller than the power generation region R1, as in the first embodiment.

[0093] It should be noted that the irradiation area of ​​the excitation light and the variation (coefficient of variation) of the irradiation area of ​​the excitation light are configured in the same way as in the first embodiment. Here, when multiple irradiation areas S are formed in one photoelectric conversion cell 220, it should be noted that when calculating the irradiation area of ​​the excitation light and the variation (coefficient of variation) of the irradiation area of ​​the excitation light, the irradiation area of ​​the excitation light is defined by the sum of the areas of the multiple irradiation areas S formed in one photoelectric conversion cell 220.

[0094] In the fifth embodiment, since each of the multiple light sources 110 is provided corresponding to each of the photoelectric conversion cells 220, the optical element 300 described in the above embodiments is unnecessary. However, the multiple light sources 110 and the optical element 300 for splitting the excitation light may be used in combination.

[0095] Even when the light-emitting device 100 has multiple light sources 110, it is desirable that the power supply system be configured so that excitation light is simultaneously irradiated onto each photoelectric conversion cell 220. Therefore, it is preferable that the multiple light sources 110 irradiate with excitation light simultaneously.

[0096] In the first to fourth embodiments, one excitation light irradiation area S is formed in one photoelectric conversion cell 220. Alternatively, in the first to fourth embodiments, as in the fifth embodiment, the power supply system may be configured so that multiple excitation light irradiation areas S are formed in one photoelectric conversion cell 220.

[0097] [Sixth Embodiment] A power supply system and power supply method according to the sixth embodiment will now be described. Figure 15 is a schematic plan view showing the configuration of the photoelectric conversion element of the light receiving device in the power supply system according to the sixth embodiment.

[0098] In the sixth embodiment, components similar to those in the first embodiment are denoted by the same reference numerals. Note that the description of components similar to those in the first embodiment may be omitted.

[0099] The power supply system according to the sixth embodiment may include, similar to the first embodiment, a light-emitting device 100 that emits excitation light and a light-receiving device 200 that receives the excitation light emitted from the light-emitting device 100. The light-receiving device 200 has a photoelectric conversion element 210.

[0100] In the sixth embodiment, the photoelectric conversion element 210 has a plurality of photoelectric conversion cells 220 arranged in a grid. The plurality of photoelectric conversion cells 220 are integrated on a substrate. The plurality of photoelectric conversion cells 220 may be electrically connected in series and / or in parallel. For example, a plurality of unit rows in which some of the plurality of photoelectric conversion cells 220 are electrically connected in series may be formed, and the unit rows consisting of the plurality of electrically connected photoelectric conversion cells 220 may be connected in parallel.

[0101] Although not shown in the figures, in the sixth embodiment as well, the power supply system may be configured so that excitation light, separated to correspond to each of the photoelectric conversion cells 220, reaches the multiple photoelectric conversion cells 220. Such separated excitation light can be realized by the optical element 300, the multiple light sources 110, or a combination of the optical element 300 and the multiple light sources 110, as described in the embodiments described above.

[0102] [Experimental Examples 1-3] Next, experimental examples will be described with reference to Figures 16, 17, and 18. Figures 16 and 17 are schematic plan views illustrating the irradiation area of ​​the excitation light in the power supply system related to the experimental examples. Figure 18 is a graph showing the experimental results of the photoelectric conversion efficiency η in experimental examples 1 to 3.

[0103] The power supply systems in Experimental Examples 1-3 have the same configuration as shown in Figure 11. However, the light-emitting device 100, light-receiving device 200, optical element 300, and plano-concave lens 350 were not mounted on the first device 10 and the second device 20, but were fixed in the laboratory.

[0104] In Experimental Examples 1-3, the photodetector 200 has the same configuration as shown in Figures 2, 3, and 10. That is, the photodetector 200 has two photoelectric conversion cells 220 (see also Figure 16). The two photoelectric conversion cells 220 are electrically connected in series with each other.

[0105] The length L1 in the X-axis direction of the power generation region R1 of each photoelectric conversion cell 220 is approximately 10 mm, and the length L2 in the Y-axis direction of the power generation region R1 of each photoelectric conversion cell 220 is approximately 20 mm. Furthermore, the length L3 in the X-axis direction of the non-power generation region R2 that exists between the power generation regions R1 of each photoelectric conversion cell 220 is 0.12 mm.

[0106] In Experimental Examples 1-3, the light-emitting device 100 had a single light source 110, which emitted laser light (excitation light) with a wavelength of 1064 nm. The output power of the laser light was 156 mW.

[0107] In Experimental Example 1, the length L5 in the X-axis direction of the laser beam irradiation area S irradiated onto each photoelectric conversion cell 220 was approximately 4 mm, and the length L6 in the Y-axis direction of the laser beam irradiation area S was approximately 14 mm.

[0108] In Experimental Example 2, the length L5 in the X-axis direction of the laser beam irradiation area S irradiated onto each photoelectric conversion cell 220 was approximately 4 mm, and the length L6 in the Y-axis direction of the laser beam irradiation area S was approximately 10 mm.

[0109] In Experimental Example 3, the length L5 in the X-axis direction of the laser beam irradiation area S irradiated onto each photoelectric conversion cell 220 was approximately 4 mm, and the length L6 in the Y-axis direction of the laser beam irradiation area S was approximately 4 mm.

[0110] In each of the experimental examples 1 to 3, the laser light was first irradiated so that the center of the irradiation area S of each laser beam coincided with the reference position RC of each photoelectric conversion cell 220. In this state, the overall photoelectric conversion efficiency η of the photoelectric conversion cell 220 was measured. pv We measured it.

[0111] Next, in each of the experimental examples 1 to 3, the laser beam was irradiated such that the center of the irradiation area S of each laser beam was shifted by 1 mm in the X-axis direction from the reference position RC of each photoelectric conversion cell 220 (see also Figure 17). That is, the shift of the irradiation area S from the reference position RC is 1 mm. In this state, the overall photoelectric conversion efficiency η of the photoelectric conversion cell 220 was... pv We measured it.

[0112] Furthermore, in each of the experimental examples 1 to 3, the laser beam was irradiated so that the center of the irradiation area S of each laser beam was shifted by an additional 1 mm in the X-axis direction from the reference position RC of each photoelectric conversion cell 220. That is, the shift of the irradiation area S from the reference position RC was 2 mm. In this state, the overall photoelectric conversion efficiency η of the photoelectric conversion cell 220 was measured. pv The photoelectric conversion efficiency η was measured while shifting the irradiation area S by 1 mm in the X-axis direction from the reference position RC. pv We measured it.

[0113] Figure 18 is a graph showing the experimental results of the photoelectric conversion efficiency η in experimental examples 1 to 3. Referring to Figure 18, the photoelectric conversion efficiency η in experimental examples 1 to 3 pv The deviation of the irradiation area S from the reference position RC remains almost constant within a range of ±3 mm. This indicates that even if the irradiation position S of the laser beam shifts slightly, fluctuations in the power obtained by the entire photoelectric conversion cell 220 can be suppressed.

[0114] [Reference example] Next, we will explain the reference example. The configuration of the power supply system and experimental conditions in the reference example are the same as in Experimental Examples 1 to 3, except for the laser light irradiation area S.

[0115] Figure 19 is a schematic plan view illustrating the irradiation area of ​​the excitation light in the power supply system according to the reference example. In the reference example, the irradiation area S of the laser light (excitation light) is a single region spanning the power generation regions R1 of the two photoelectric conversion cells 220. That is, the irradiation area S of the laser light also overlaps with the non-power generation region R2 between the power generation regions R1 of the two photoelectric conversion cells 220. The length L5 in the X-axis direction of the irradiation area S of the laser light was approximately 16 mm, and the length L6 in the Y-axis direction of the irradiation area S of the laser light was approximately 16 mm.

[0116] In the example, the laser beam was first irradiated so that the center of the laser beam irradiation area S coincided with the reference position RC. In the example, the reference position RC is located at the center of the entire power generation region R2 of the two photoelectric conversion cells 220, i.e., within the non-power generation region R2. In this state, the photoelectric conversion efficiency η of the entire photoelectric conversion cell 220 is... pv We measured it.

[0117] Next, similar to experimental examples 1-3, the photoelectric conversion efficiency η is measured while shifting the center of the laser beam irradiation area S by 1 mm in the X-axis direction from the reference position RC. pv We measured it.

[0118] Figure 20 is a graph showing the experimental results of the photoelectric conversion efficiency η in the reference example. Referring to Figure 20, in the reference example, the center of the laser beam irradiation area S is shifted from the reference position RC, and the photoelectric conversion efficiency η pv The power output decreases. In other words, if the laser beam irradiation position S is slightly shifted, the power obtained from the entire photoelectric conversion cell 220 also decreases. If the center of the laser beam irradiation area S is even slightly shifted from the reference position RC, the irradiation area of ​​the laser beam irradiated onto one of the two photoelectric conversion cells 220 becomes smaller. As a result, a difference is created in the energy that the two photoelectric conversion cells receive from the excitation light, and the total current value of the two photoelectric conversion cells 220 is limited to the current value generated by the photoelectric conversion cell that receives less energy. Consequently, as described above, the power obtained from the entire photoelectric conversion cell 220 also decreases.

[0119] Comparing experimental examples 1-3 with the reference example, it can be seen that the present invention provides a power supply system and power supply method that can suppress fluctuations in the power obtained throughout the photoelectric conversion cell even if the irradiation position of the excitation light is slightly shifted.

[0120] As described above, the scope of the present invention has been disclosed through embodiments, but the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. Therefore, the technical scope of the present invention is defined solely by the inventive features relating to the claims that are reasonable from the above description.

[0121] Each feature described in the aforementioned embodiments can be applied to or replaced with those of other embodiments as much as possible. [Explanation of Symbols]

[0122] 100 Light-emitting devices 110 Light source 200 Photodetector 220 Photoelectric conversion cells 300 optical elements 400 masks R1 Power Generation Area S Irradiation area

Claims

1. A power supply system, A light-emitting device that emits excitation light, The device includes a light receiving device that receives excitation light emitted from the light-emitting device, The light receiving device has a plurality of photoelectric conversion cells, The power supply system is configured such that excitation light, separated to correspond to each of the photoelectric conversion cells, reaches a plurality of the photoelectric conversion cells.

2. The power supply system according to claim 1, wherein the irradiation area of ​​the excitation light irradiated onto each of the photoelectric conversion cells is configured to be smaller than the power generation area of ​​the photoelectric conversion cells.

3. The power supply system according to claim 1 or 2, wherein the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell is configured to be 5% or more and 90% or less of the area of ​​the power generation region of the photoelectric conversion cell.

4. The power supply system according to any one of claims 1 to 3, wherein the coefficient of variation obtained by dividing the standard deviation of the irradiation area of ​​the excitation light irradiated onto the plurality of photoelectric conversion cells by the average value of the irradiation area of ​​the excitation light irradiated onto the plurality of photoelectric conversion cells is 0.7 or less.

5. The power supply system according to any one of claims 1 to 4, wherein each of the photoelectric conversion cells is configured to receive one excitation light or a plurality of divided excitation lights.

6. The power supply system according to any one of claims 1 to 5, wherein the shape of the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell is configured to be similar to the shape of the power generation region of the photoelectric conversion cell.

7. A power supply system according to any one of claims 1 to 6, comprising a light mask having a window for shaping the irradiation area of ​​excitation light.

8. The power supply system according to any one of claims 1 to 7, wherein the light-emitting device has a plurality of light sources that emit excitation light.

9. The power supply system according to claim 8, wherein each of the plurality of light sources is provided in correspondence with each of the plurality of photoelectric conversion cells.

10. The light-emitting device has at least one light source that emits excitation light, The power supply system according to any one of claims 1 to 7, wherein the power supply system has an optical element that separates the excitation light emitted from the light source into a plurality of excitation lights.

11. The power supply system according to claim 10, wherein the optical element includes a diffractive beam splitter.

12. The power supply system according to claim 10, wherein the optical element includes a light mask having a plurality of windows for passing excitation light.

13. The power supply system according to any one of claims 10 to 12, wherein the optical element is provided in the light-emitting device.

14. The power supply system according to any one of claims 10 to 12, wherein the optical element is provided in the light receiving device.

15. The power supply system according to any one of claims 1 to 14, wherein the excitation light is configured to irradiate each of the photoelectric conversion cells simultaneously.

16. The power supply system according to any one of claims 1 to 15, wherein the positional relationship between the light-emitting device and the light-receiving device is configured to be variable.

17. It has multiple photoelectric conversion cells that receive excitation light, and optical elements, The optical element is configured to separate the excitation light passing through the optical element into multiple beams, and to direct each of the separated beams of excitation light to a corresponding number of photoelectric conversion cells, in a light-receiving device.

18. The light receiving device according to claim 17, wherein the optical elements are configured such that the irradiation area of ​​the excitation light irradiated onto each of the photoelectric conversion cells is smaller than the power generation area of ​​the photoelectric conversion cells.

19. The light receiving device according to claim 17 or 18, wherein the optical elements are configured such that the irradiation area of ​​the excitation light irradiated onto each of the photoelectric conversion cells is 5% or more and 90% or less of the area of ​​the power generation region of the photoelectric conversion cells.

20. The light receiving device according to any one of claims 17 to 19, wherein the optical element is configured such that one or more of the excitation lights separated by passing through the optical element reach each of the photoelectric conversion cells.

21. The light receiving device according to any one of claims 17 to 20, wherein the optical element includes a diffractive beam splitter.

22. The light receiving device according to any one of claims 17 to 20, wherein the optical element includes a light mask having a plurality of windows for passing excitation light.

23. It has a base to which the plurality of photoelectric conversion cells are attached, The light receiving device according to any one of claims 17 to 22, wherein the optical element is integrally provided with the base.

24. It has a base to which the plurality of photoelectric conversion cells are attached, The light receiving device according to any one of claims 17 to 22, wherein the optical element is detachable from the base.

25. A power supply method comprising the step of emitting excitation light from a light-emitting device and causing the excitation light, separated to correspond to each of the multiple photoelectric conversion cells provided in a light-receiving device, to reach the multiple photoelectric conversion cells.

26. The power supply method according to claim 25, wherein the irradiation area of ​​the excitation light irradiated onto each of the photoelectric conversion cells is smaller than the power generation area of ​​the photoelectric conversion cells.

27. The power supply method according to claim 25 or 26, wherein the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell is 5% or more and 90% or less of the area of ​​the power generation region of the photoelectric conversion cell.

28. The power supply method according to any one of claims 25 to 27, wherein the coefficient of variation obtained by dividing the standard deviation of the irradiation area of ​​the excitation light irradiated onto the plurality of photoelectric conversion cells by the average value of the irradiation area of ​​the excitation light irradiated onto the plurality of photoelectric conversion cells is 0.7 or less.

29. The power supply method according to any one of claims 25 to 28, wherein the shape of the irradiation area of ​​the excitation light irradiated onto the photoelectric conversion cell is similar to the shape of the power generation region of the photoelectric conversion cell.

30. The light-emitting device has a light source, A power supply method according to any one of claims 25 to 29, comprising separating excitation light emitted from the light source into a plurality of excitation lights, and irradiating each of the separated excitation lights with a corresponding photoelectric conversion cell.

31. The power supply method according to any one of claims 25 to 30, comprising simultaneously irradiating each of the photoelectric conversion cells with the excitation light.

32. A power supply method according to any one of claims 25 to 31, comprising emitting excitation light from the light-emitting device while changing the positional relationship between the light-emitting device and the light-receiving device.

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