Solar cell and maintenance system for solar cell

Abstract

The invention provides a solar cell unit and a maintenance system for the solar cell unit, wherein a film-type solar cell and a non-film-type solar cell can be used at the same time, and the film-type solar cell can be easily replaced. The solar cell unit (2) is provided with a film-type solar cell (21) disposed on the light incident side, a non-film-type solar cell (22) disposed on the opposite side of the film-type solar cell (21) from the light incident side, and a winding mechanism (23) for winding the film-type solar cell (21). The film-type solar cell (21) can slide with respect to the non-film-type solar cell (22) by the winding mechanism (23).

Description

Technical Field

[0001] The present invention relates to a solar cell unit and a maintenance system for a solar cell unit. Background Art

[0002] As solar cells, crystalline silicon-based solar cells and perovskite solar cells are well known. Regarding crystalline silicon-based solar cells, since they have high efficiency in converting absorbed light energy into electrical energy and high performance and reliability, in addition to being installed on the roofs and outer walls of buildings for use, as described in Patent Document 1 below, they are also installed on the roofs and sides of vehicles for use.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-184833 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, crystalline silicon-based solar cells have the drawback that the light energy absorption efficiency decreases when they are thinned, so it is necessary to ensure a practical thickness. In addition, crystalline silicon-based solar cells have a hard glass component, so it is not easy to make them thin and flexible. Therefore, it is difficult to fabricate crystalline silicon-based solar cells into film-type solar cells. On the other hand, regarding perovskite solar cells, the light energy absorption coefficient is large, and high conversion efficiency can be maintained even when thinned. Moreover, perovskite solar cells are lighter, thinner, and more flexible than crystalline silicon-based solar cells, so it is possible to easily realize a flexible film-type solar cell.

[0008] Recently, in order to be able to use both film-type solar cells typified by perovskite solar cells and non-film-type solar cells typified by crystalline silicon-based solar cells, a tandem structure in which these solar cells are stacked has attracted attention. However, perovskite solar cells are easily affected by light, heat, and moisture, so their durability is lower than that of crystalline silicon-based solar cells. Therefore, in the above tandem structure, there is a problem that it is difficult to replace the perovskite solar cell at the same timing as the crystalline silicon-based solar cell.

[0009] The present invention has been made to solve such technical problems, and an object thereof is to provide a solar cell unit and a maintenance system therefor that can easily replace a film-type solar cell while using both a film-type solar cell and a non-film-type solar cell.

[0010] Means for Solving the Problems

[0011] The solar cell unit of the present invention is characterized by comprising: a film-type solar cell disposed on the light incident side; a non-film-type solar cell disposed on the side opposite to the light incident side of the film-type solar cell; and a winding mechanism that winds the film-type solar cell, and the film-type solar cell can slide relative to the non-film-type solar cell through the winding mechanism.

[0012] In the solar cell unit of the present invention, since a film-type solar cell disposed on the light incident side and a non-film-type solar cell disposed on the side opposite to the light incident side of the film-type solar cell are provided, short-wavelength light energy can be absorbed by the film-type solar cell and converted into electric energy, and long-wavelength light energy can be absorbed by the non-film-type solar cell and converted into electric energy. Thus, the film-type solar cell and the non-film-type solar cell can be used in combination, and the power generation efficiency of the solar cell unit can be improved. In addition, since the film-type solar cell can slide relative to the non-film-type solar cell through the winding mechanism, the film-type solar cell can be easily replaced by winding the film-type solar cell. As a result, the film-type solar cell can be easily replaced at an appropriate timing while using the film-type solar cell and the non-film-type solar cell in combination.

[0013] In the solar cell unit of the present invention, preferably, the winding mechanism has: a first housing that houses the unused film-type solar cell; a second housing that is disposed separately from the first housing so as to provide a power generation area therebetween; and a winding portion that discharges the unused film-type solar cell housed in the first housing to the power generation area and houses the film-type solar cell discharged to the power generation area in the second housing. In this way, the unused film-type solar cell can be easily discharged, and the used-up film-type solar cell can be easily housed. Therefore, the replacement of the film-type solar cell can be easily achieved.

[0014] In the solar cell unit of the present invention, preferably, the film-type solar cell is a perovskite-type solar cell, and the non-film-type solar cell is a crystalline silicon-based solar cell. In this way, the advantages of the perovskite-type solar cell and the crystalline silicon-based solar cell can be utilized respectively, the combination of the film-type solar cell and the non-film-type solar cell can be easily achieved, and the cost of the solar cell unit can be reduced.

[0015] In addition, the maintenance system for a solar cell unit according to the present invention is a maintenance system for a solar cell unit that performs the above-described maintenance of the solar cell unit, and is characterized in that the maintenance system includes: an infrared imaging unit that captures an infrared image of the surface of the film-type solar cell located in the power generation area; and a control unit that controls the operation of the winding mechanism based on the image captured by the infrared imaging unit.

[0016] In the maintenance system for a solar cell unit according to the present invention, the control unit controls the operation of the winding mechanism based on the infrared image captured by the infrared imaging unit. Therefore, when it is determined that the film-type solar cell needs to be replaced, the replacement can be easily performed at an appropriate timing, and thus the power generation efficiency of the solar cell unit can be maintained.

[0017] In the maintenance system for a solar cell unit according to the present invention, preferably, the control unit determines whether the abnormal heating area of the film-type solar cell exceeds a preset abnormal heating area threshold based on the infrared image captured by the infrared imaging unit. When it is determined that the abnormal heating area exceeds the abnormal heating area threshold, the control unit controls the winding mechanism to replace the film-type solar cell located in the power generation area. In this way, when the control unit determines that the abnormal heating area exceeds the abnormal heating area threshold, it controls the winding mechanism to replace the film-type solar cell located in the power generation area, whereby the replacement of the film-type solar cell can be easily performed at an appropriate timing.

[0018] In the maintenance system for a solar cell unit according to the present invention, preferably, it further includes a sensor that measures the temperature and humidity inside the first housing. The control unit determines whether the temperature inside the first housing exceeds 50°C and whether the humidity inside the first housing exceeds 50% based on the measurement results of the sensor. When it is determined that the temperature inside the first housing exceeds 50°C and the humidity inside the first housing exceeds 50%, it notifies of such exceedance. In this way, deterioration of the film-type solar cell due to heat and moisture can be prevented.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to easily replace the film-type solar cell while using both the film-type solar cell and the non-film-type solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic configuration diagram showing a solar cell unit and a maintenance system for a solar cell unit.

[0022] Figure 2 It is a schematic cross-sectional view showing the structure of a film-type solar cell.

[0023] Figure 3 It is a schematic plan view showing a thin-film solar cell.

[0024] Figure 4 It is a schematic view showing a solar cell unit installed in a vehicle.

[0025] Explanation of reference numerals

[0026] 1: Maintenance system of solar cell unit, 2: Solar cell unit, 3: Control unit, 4: Drone (infrared imaging unit), 5: Sensor, 10: Vehicle, 21: Thin-film solar cell, 21A: Single cell, 21B: Insulating part, 22: Non-thin-film solar cell, 23: Rewinding mechanism, 24: First housing, 25: Second housing, 26: Rewinding part, 27: Mounting plate, 101: Side surface, 102: Upper surface, 211: Substrate, 212: Transparent electrode, 213: Hole transport layer, 214: Photoelectric layer, 215: Electron transport layer, 216: Electrode, 217: Resin sealing layer, 218: Barrier film, 261: Support shaft, 262: Driving shaft for rewinding, 263: First free roller, 264: Second free roller, 265: Third free roller, 266: Driving shaft for tension Detailed implementation mode

[0027] Hereinafter, with reference to the drawings, embodiments of the solar cell unit and the maintenance system of the solar cell of the present invention will be described. In the description of the drawings, the same reference numerals are assigned to the same elements, and repeated description thereof is omitted.

[0028] Figure 1 It is a schematic configuration diagram showing a solar cell unit and a maintenance system of the solar cell unit. The maintenance system 1 of the solar cell unit in the present embodiment is a system for maintaining the solar cell unit 2 (for example, replacement of the solar cell unit 2, repair of the solar cell unit 2), and includes a drone 4 equipped with an infrared camera and a control unit 3 for controlling the entire system. Hereinafter, the solar cell unit 2 will be described first, and then the maintenance system 1 of the solar cell unit will be described.

[0029] [Regarding the solar cell unit]

[0030] As Figure 1As shown, the solar cell unit 2 is detachably mounted on the side surface 101 of the vehicle 10, for example. The solar cell unit 2 includes: a film-type solar cell 21 disposed on the light incident side, a non-film-type solar cell 22 disposed on the side opposite to the light incident side of the film-type solar cell 21, and a winding mechanism 23 for winding the film-type solar cell 21. In addition, in the present embodiment, the "light incident side" refers to the side where sunlight is incident.

[0031] The film-type solar cell 21 is a thin and flexible so-called flexible solar cell. Examples of the film-type solar cell 21 include a perovskite solar cell, an amorphous silicon solar cell, and the like. Hereinafter, an example of a perovskite solar cell will be given to illustrate the structure of the film-type solar cell 21.

[0032] Figure 2 It is a schematic cross-sectional view showing the structure of the film-type solar cell, Figure 3 It is a schematic plan view showing the film-type solar cell. As Figure 2 and Figure 3 shown, the film-type solar cell 21 is formed by alternately arranging a plurality of single cells 21A and a plurality of insulating portions 21B along the length direction of the film-type solar cell 21. The single cell 21A has a substrate 211, a transparent electrode 212, a hole transport layer 213, a photoelectric layer 214, an electron transport layer 215, and an electrode 216. Moreover, the substrate 211, the transparent electrode 212, the hole transport layer 213, the photoelectric layer 214, the electron transport layer 215, and the electrode 216 are sealed by a resin sealing layer 217, but a part of the substrate 211, the transparent electrode 212, and the electrode 216 is exposed from the resin sealing layer 217. Further, barrier films 218 are provided on both sides (the light incident side and the side opposite thereto) of the resin sealing layer 217.

[0033] And, the transparent electrode 212 of each single cell 21A is electrically connected to, for example, a negative terminal (not shown) provided on the winding drive shaft 262, and the electrode 216 of each single cell 21A is electrically connected to, for example, a positive terminal (not shown) provided on the winding drive shaft 262.

[0034] The substrate 211 is formed of, for example, transparent glass or polyethylene terephthalate (PET), the transparent electrode 212 is formed of a mixture of indium oxide and tin oxide, i.e., ITO (Indium Tin Oxide), the hole transport layer 213 is formed of Spiro-OMeTAD, the photoelectric layer 214 is formed of a CH3NH3PbI3 perovskite material, the electron transport layer 215 is formed of titanium oxide, and the electrode 216 is formed of Au.

[0035] On the other hand, the insulating portion 21B is a portion where the perovskite material is not coated or printed, and is formed only of the barrier film 218, for example, and is integrated with the adjacent single cell 21A.

[0036] The non-film type solar cell 22 is, for example, a crystalline silicon-based solar cell. Since the crystalline silicon-based solar cell is a solar cell used in well-known solar cell panels, the description of its structure and the like is omitted.

[0037] The winding mechanism 23 includes: a first housing 24 that houses the unused film type solar cell 21; a second housing 25 that is disposed separately from the first housing 24 so as to form a power generation area S therebetween; and a winding portion 26 that discharges the unused film type solar cell 21 housed in the first housing 24 to the power generation area S and houses the film type solar cell 21 discharged to the power generation area S in the second housing 25.

[0038] The first housing 24 is formed in a box shape from an aluminum material, for example, and is fixed to one end portion of the mounting plate 27. Inside the first housing 24, in addition to the unused film type solar cell 21, a part of the components of the winding portion 26 is also housed. Further, the unused film type solar cell 21 is axially supported by a support shaft 261 (described later) inside the first housing 24 in a state of being wound into a roll (roll shape). In addition, an opening for taking out the housed film type solar cell 21 to the outside of the first housing 24 is provided on the wall surface of the first housing 24 that faces the second housing 25.

[0039] The second housing 25 is formed in a box shape from an aluminum material, for example, and is fixed to the other end portion of the mounting plate 27 so as to face the first housing 24. And the space between the first housing 24 and the second housing 25 constitutes the above-described power generation area S. A winding drive shaft 262 is housed inside the second housing 25. In addition, corresponding to the opening of the first housing 24, an opening for taking the film type solar cell 21 into the inside of the housing is also provided on the wall surface of the second housing 25 that faces the first housing 24.

[0040] The mounting plate 27 is formed of a metal material such as aluminum, for example, and serves to fix the first housing 24, the second housing 25, and the non-film type solar cell 22, and also serves as a mounting member when the solar cell unit 2 is mounted on the side surface 101 of the vehicle 10.

[0041] The take-up unit 26 includes: a support shaft 261 disposed inside the first housing 24, a take-up drive shaft 262 disposed inside the second housing 25, a first idle roller 263, a second idle roller 264, and a third idle roller 265 arranged in sequence from the support shaft 261 toward the take-up drive shaft 262, and a tension drive shaft 266 close to the second idle roller 264.

[0042] The support shaft 261 supports the unused film-type solar cell 21 wound into a roll in a rotatable state. For example, it is in the shape of a round bar, with one end fixed to the inner wall of the first housing 24 and the other end being a free end. The unused film-type solar cell 21 is formed in a long size with a certain width and wound around a hollow core. The unused film-type solar cell 21 wound in this way can be stored in the first housing 24 by inserting the free end of the support shaft 261 into the hole of the core.

[0043] The first idle roller 263, the second idle roller 264, and the third idle roller 265 are stored inside the first housing 24 and are arranged in a triangular shape to adjust the tension of the unused film-type solar cell 21. For example Figure 1 as shown, the first idle roller 263 and the third idle roller 265 are arranged linearly in the vertical direction of the vehicle 10, and the second idle roller 264 is arranged closer to the vehicle 10 side than the first idle roller 263 and the third idle roller 265.

[0044] The tension drive shaft 266 is arranged at a position close to the second idle roller 264 to apply tension to the unused film-type solar cell 21 so that it is released without slack. The tension drive shaft 266 is driven by an electric motor (not shown) to rotate in the direction opposite to the release direction of the film-type solar cell 21.

[0045] The take-up drive shaft 262 is driven to rotate by an electric motor (not shown), thereby releasing the unused film-type solar cell 21 stored in the first housing 24 into the power generation area S and taking up the film-type solar cell 21 released into the power generation area S.

[0046] As Figure 1 shown, in the power generation area S, the non-film-type solar cell 22 is arranged closer to the vehicle 10 side than the film-type solar cell 21. The non-film-type solar cell 22 is fixed to the mounting plate 27.

[0047] In the present embodiment, the film-type solar cell 21 and the non-film-type solar cell 22 are not integrally structured by lamination but are separate structures. Therefore, the film-type solar cell 21 and the non-film-type solar cell 22 can be arranged close to each other or separated with a certain distance.

[0048] In the take-up mechanism 23 according to the present embodiment, when the take-up drive shaft 262 is driven to rotate as indicated by the arrow, the core fixed to the take-up drive shaft 262 rotates in the direction indicated by the arrow. As a result, the film-type solar cell 21 located in the power generation area S is pulled toward the second housing 25 side and wound around the core fixed to the take-up drive shaft 262. At the same time, the unused film-type solar cell 21 stored in the first housing 24 is released toward the power generation area S.

[0049] In addition, the film-type solar cell 21 and the non-film-type solar cell 22 can be formed into a two-terminal type connected in series, or can be formed into a four-terminal type in which electrical extraction is performed separately from the film-type solar cell 21 and the non-film-type solar cell 22. And, in consideration of the ability to retrofit the non-film-type solar cell 22 later, it is preferably formed into a four-terminal type.

[0050] In the solar cell unit 2 configured as described above, the film-type solar cell 21 located in the power generation area S is arranged on the light incident side with respect to the non-film-type solar cell 22. Therefore, the film-type solar cell 21 can absorb short-wavelength light energy and convert it into electric energy, and the non-film-type solar cell 22 can absorb long-wavelength light energy and convert it into electric energy. That is, for sunlight, the film-type solar cell 21 generates electricity as a top cell, and the non-film-type solar cell 22 generates electricity as a bottom cell. By using the film-type solar cell 21 and the non-film-type solar cell 22 in this way, light with a wide range of wavelengths can be utilized, and the power generation efficiency of the solar cell unit 2 can be improved.

[0051] In addition, since the film-type solar cell 21 can slide relative to the non-film-type solar cell 22 by the take-up mechanism 23, the film-type solar cell 21 can be easily replaced by winding up the film-type solar cell 21. Therefore, the film-type solar cell 21 and the non-film-type solar cell 22 with different durabilities can be replaced separately, and the film-type solar cell 21 can be easily replaced at an appropriate timing while using the film-type solar cell 21 and the non-film-type solar cell 22.

[0052] Regarding perovskite solar cells, in addition to light and heat, they are also greatly affected by moisture. Therefore, when installing the solar cell unit 2 having a perovskite solar cell on the vehicle 10, it is necessary to pay attention to the arrangement positions of the first housing 24 and the second housing 25 in a manner that suppresses the influence caused by moisture.

[0053] For example Figure 4As shown in the figure, when the solar cell unit 2 is installed on the upper surface 102 of the vehicle 10, preferably, the first housing 24 is arranged at the front of the vehicle 10, and the second housing 25 is arranged at the rear of the vehicle 10. This is because, for example, when water droplets adhere to the upper surface 102 of the vehicle 10, as the vehicle 10 moves, the adhered water droplets move from the front to the rear of the vehicle 10. Therefore, by arranging the unused perovskite solar cells at the front of the vehicle and the used-up perovskite solar cells at the rear of the vehicle, it is possible to suppress the deterioration of the unused perovskite solar cells caused by moisture and prevent the generation of hot spots (to be described below) due to deterioration.

[0054] On the other hand, when the solar cell unit 2 is installed on the side surface 101 of the vehicle 10, preferably, the first housing 24 is arranged above the vehicle 10, and the second housing 25 is arranged below the vehicle 10. This is because, for example, when water droplets adhere to the side surface 101 of the vehicle 10, when the vehicle temporarily stops or parks, the adhered water droplets move from the upper part to the lower part of the vehicle 10 due to gravity. Therefore, by arranging the unused perovskite solar cells above the vehicle and the used-up perovskite solar cells below the vehicle, it is possible to suppress the deterioration of the unused perovskite solar cells caused by moisture and prevent the generation of hot spots due to deterioration.

[0055] [Regarding the maintenance system of the solar cell unit]

[0056] As described above, the maintenance system 1 of the solar cell unit of the present embodiment includes a drone 4 and a control unit 3. The drone 4 corresponds to the "infrared imaging unit" described in the claims, captures an infrared image of the surface of the film-type solar cell 21 located in the power generation area S, and outputs it to the control unit 3. The drone 4 is connected to the control unit 3 in a communicable manner, captures an infrared image of the surface of the film-type solar cell 21 during power generation, and transmits the captured infrared image together with associated position information, etc. to the control unit 3.

[0057] The control unit 3 is constituted by, for example, the following microcomputer, which is a combination of a CPU (Central Processing Unit) that performs operations, a ROM (Read Only Memory) that is a secondary storage device recording programs for operations, and a RAM (Random Access Memory) that is a temporary storage device for storing the operation process and temporarily storing control variables. The control unit 3 performs overall control of the maintenance system 1 of the solar cell unit by executing the stored programs.

[0058] For example, the control unit 3 controls the operation timing, operation time, etc. of the take-up drive shaft 262 and the tension drive shaft 266 for the take-up mechanism 23 communicably connected thereto. In addition, the control unit 3 controls the automatic navigation, shooting timing, shooting time, etc. of the drone 4.

[0059] When generating electricity using a thin-film solar cell 21 such as a perovskite solar cell, hot spots sometimes occur. A hot spot refers to the generation of a high-resistance portion in a part of the thin-film solar cell 21 (for example, a part of a perovskite solar cell single cell), resulting in abnormal heat generation. As causes of hot spot generation, external causes such as the attachment of bird droppings and fallen leaves and internal causes such as poor solder wiring and single cell breakage due to aging deterioration can be cited. And if hot spots occur, it will lead to a reduction in power generation. Therefore, it is necessary to replace the thin-film solar cell 21.

[0060] In order to detect the presence or absence of hot spots, in the present embodiment, the drone 4 equipped with the above infrared camera is used to perform aerial photography (aerial shooting) of the thin-film solar cell 21 located in the power generation area S from a high position, and the presence or absence of hot spots is confirmed based on the thermal image (infrared image) of the thin-film solar cell 21. For example, when the vehicle is stopped, this inspection is performed using the drone in a state where the solar cell unit 2 is operating. In this case, since it is possible to inspect each solar cell unit 2 of multiple stopped vehicles with one drone in a short time, the maintenance efficiency can be improved.

[0061] At this time, the control unit 3 determines whether the abnormal heat generation area of the thin-film solar cell 21 located in the power generation area S exceeds a preset abnormal heat generation area threshold based on the infrared image captured by the drone 4. Specifically, the control unit 3 calculates the abnormal heat generation area of the thin-film solar cell 21 located in the power generation area S based on the infrared image of the thin-film solar cell 21, and compares the calculated result of the abnormal heat generation area with the preset abnormal heat generation area threshold, thereby determining whether the abnormal heat generation area exceeds the abnormal heat generation area threshold.

[0062] And when it is determined that the abnormal heat generation area exceeds the abnormal heat generation area threshold, the control unit 3 controls the take-up mechanism 23 to replace the thin-film solar cell 21 located in the power generation area S. Specifically, when it is determined that the abnormal heat generation area exceeds the abnormal heat generation area threshold, the control unit 3 sends control commands to the take-up drive shaft 262 and the tension drive shaft 266 to drive the take-up drive shaft 262 and the tension drive shaft 266 to rotate respectively.

[0063] If the take-up drive shaft 262 and the tension drive shaft 266 are respectively driven to rotate, the film-type solar cell 21 located in the power generation area S (i.e., the film-type solar cell 21 having hot spots) slides relative to the non-film-type solar cell 22 and is housed in the second housing 25. At the same time, the unused film-type solar cell 21 housed in the first housing 24 is released toward the power generation area S. Thereby, the film-type solar cell 21 located in the power generation area S is replaced.

[0064] In addition, when it is determined that the abnormal heating area does not exceed the abnormal heating area threshold, the control unit 3 does not operate the take-up mechanism. That is, the film-type solar cell 21 located in the power generation area S is not replaced and continues to be used for power generation.

[0065] In addition, the position information of the hot spot is also included in the infrared image captured by the drone 4. The control unit 3 can determine the position of the hot spot based on the position information of the hot spot. Furthermore, the control unit 3 determines whether to replace the entire film-type solar cell 21 located in the power generation area S or to perform a partial replacement based on the determined position of the hot spot.

[0066] For example, when the hot spot exists throughout the entire film-type solar cell 21 located in the power generation area S, the control unit 3 determines that the entire film-type solar cell 21 located in the power generation area S needs to be replaced, and sends control commands to the take-up drive shaft 262 and the tension drive shaft 266 to control the rotation speed and rotation time of the take-up drive shaft 262 and the tension drive shaft 266 in such a way that the entire film-type solar cell 21 located in the power generation area S can be replaced.

[0067] On the other hand, for example, when the hot spot does not exist throughout the entire film-type solar cell 21 located in the power generation area S but exists on the side of the second housing 25, the control unit 3 determines that the entire film-type solar cell 21 located in the power generation area S is not replaced and only the side of the second housing 25 where the hot spot exists is replaced. At this time, the control unit 3 controls the rotation speed and rotation time of the take-up drive shaft 262 and the tension drive shaft 266 in such a way that only the side of the second housing 25 where the hot spot exists in the film-type solar cell 21 located in the power generation area S can be replaced. In this way, by appropriating the available film-type solar cells 21, cost reduction of the solar cell unit 2 can be achieved.

[0068] In the maintenance system of the solar cell unit according to the present embodiment, the control unit 3 determines whether the abnormal heating area of the film-type solar cell 21 exceeds the abnormal heating area threshold based on the infrared image captured by the drone 4. When it is determined that the abnormal heating area exceeds the abnormal heating area threshold, the control unit controls the winding mechanism 23 to replace the film-type solar cell 21 located in the power generation area S. In this way, it is possible to easily grasp whether there is a hot spot in the film-type solar cell 21, and when a hot spot occurs, it is possible to easily replace the film-type solar cell 21 at an appropriate timing. As a result, it is possible to prevent a decrease in the power generation amount of the solar cell unit 2 caused by the hot spot and maintain the power generation efficiency of the solar cell unit 2.

[0069] In addition, as Figure 1 and Figure 4 shown, preferably, the maintenance system 1 of the solar cell unit according to the present embodiment further includes a sensor 5 that measures the temperature and humidity inside the first housing 24. The sensor 5 is fixed to the inner wall of the solar cell unit 2, for example, measures the temperature and humidity inside the first housing 24 respectively, and transmits the measurement results to the control unit 3.

[0070] The control unit 3 determines whether the temperature inside the first housing 24 exceeds a preset temperature threshold and whether the humidity inside the first housing 24 exceeds a preset humidity threshold based on the measurement results of the sensor 5. In the present embodiment, based on the results of Example 2 described later, the temperature threshold is set to 50 °C, and the humidity threshold is set to 50%. Therefore, the control unit 3 determines whether the temperature inside the first housing 24 exceeds 50 °C and whether the humidity inside the first housing 24 exceeds 50%.

[0071] And when it is determined that the temperature inside the first housing 24 exceeds 50 °C and the humidity inside the first housing 24 exceeds 50%, the control unit 3 notifies the driver of the vehicle 10 and / or the manager of the maintenance system 1 of the solar cell unit, etc. of this excess. As a notification method, for example, it is possible to consider displaying on a display provided in the cab of the vehicle 10 or the system management room, and notifying the driver and the manager by sound.

[0072] By doing so, the driver and the manager can grasp that the temperature and humidity inside the first housing 24 respectively exceed the thresholds. Therefore, by taking measures such as reducing the temperature and humidity inside the first housing 24 from the time of notification until a certain time (for example, 15 minutes) has passed (for example, the driver temporarily parks the vehicle 10 in the shade), it is possible to prevent deterioration of the unused film-type solar cell 21 stored in the first housing 24.

[0073] Assuming that no measures are taken to reduce the temperature and humidity inside the first housing 24, when a certain period of time (e.g., 15 minutes) has elapsed since the notification, the unused thin-film solar cell 21 housed in the first housing 24 is discarded due to deterioration. In this case, it is only necessary to replace the deteriorated unused thin-film solar cell 21 with a new one.

[0074] As described above, perovskite solar cells are susceptible to heat (temperature) and moisture (humidity) in addition to light. For example, CH3NH3PbI3, which is a perovskite material, reacts with water to become PbI2. As a result, since the photoelectric layer of the thin-film solar cell decomposes, the thin-film solar cell deteriorates and changes color (becomes yellow). Then, the inventors of the present application investigated the effects of temperature and humidity on the thin-film solar cell 21.

[0075] [Example 1]

[0076] First, the inventors of the present application fabricated a plurality of flat samples having the structure of the above-described thin-film solar cell 21, divided the fabricated samples into two groups, and respectively performed a high-temperature endurance test (120°C × 360 h) and a low-temperature endurance test (-40°C × 240 h). Then, it was confirmed whether or not the samples in each group changed color. As a result, the samples in the high-temperature endurance test changed color, while on the other hand, the samples in the low-temperature endurance test hardly changed color. From this result, it can be seen that the heat resistance of perovskite solar cells is relatively weak.

[0077] [Example 2]

[0078] In addition, the inventors of the present application fabricated a plurality of samples having the structure of the above-described thin-film solar cell 21, and investigated whether or not the samples changed color due to changes in humidity in an environment at a temperature of 50°C. More specifically, flat samples having the same structure as the thin-film solar cell 21 were fabricated, and after measuring the initial lightness (L), hue (a), and chroma (b) of the fabricated samples, the samples were placed for 15 minutes under six conditions of humidity of 50%, 55%, 60%, 65%, 70%, and 85% in an environment at a temperature of 50°C. Then, the lightness (L), hue (a), and chroma (b) of each sample were measured again, and the differences between the initial lightness, hue, and chroma of the samples and the lightness, hue, and chroma of the samples after being placed under the above conditions (i.e., ΔL, Δa, and Δb) were obtained, and ΔE was calculated using the following formula (1). Table 1 shows the test conditions and the results.

[0079] [Mathematical formula 1]

[0080]

[0081] In addition, the lightness (L), hue (a), and chroma (b) of each sample are standards determined by the International Commission on Illumination for expressing color, and are measured using devices such as a spectrocolorimeter and a variable-angle color difference meter, for example. The measurement is based on JIS Z 8781, using a spectrocolorimeter (CM-M6, manufactured by Konica Minolta Japan Co., Ltd.), irradiating light on the surface of the sample at an angle of 45°, and receiving the reflected light at an angle of 15° with respect to the irradiated light.

[0082]

Table 1

[0083]

[0084] From the results in Table 1, it can be seen that when the temperature is 50°C or lower and the humidity is 50% or lower, the color difference of the sample is small and there is almost no color change. In other words, by managing the film-type solar cell 21 in an environment where the temperature is 50°C or lower and the humidity is 50% or lower, the deterioration of the film-type solar cell 21 due to temperature and moisture can be suppressed.

[0085] In addition, from the results in Table 1, it can be seen that by taking measures such as reducing the temperature and humidity within 15 minutes from when the temperature becomes 50°C or lower and the humidity becomes 50% or lower, the deterioration of the film-type solar cell 21 can be prevented. Furthermore, by providing a barrier film or the like on the film-type solar cell 21, the time until deterioration can be extended.

[0086] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention described in the claims.

[0087] For example, in the above-described embodiment, an example in which the solar cell unit 2 is installed on the outer surface of the vehicle 10 has been described, but it may also be installed on a tram, a building, or the like. In addition, without affecting the power generation of the solar cell unit 2, the shape of the film-type solar cell 21 can be changed and a color can be imparted thereto so that the film-type solar cell 21 also has an advertising and promotional function.

Claims

1. A solar cell unit, characterized in that: have: Film-type solar cells are arranged on the light incident side; a non-film type solar cell disposed on a side of the film type solar cell opposite to the light incident side; and a winding mechanism for winding up the film-type solar cell, The film-type solar cell is slidable relative to the non-film-type solar cell by the winding mechanism.

2. The solar cell unit according to claim 1, The winding mechanism comprises: A first housing for storing the unused film-type solar cell; a second housing disposed separately from the first housing so as to provide a power generation region between the second housing and the first housing; and The winding unit releases the unused film-type solar cell stored in the first case toward the power generation region, and stores the film-type solar cell released to the power generation region in the second case.

3. The solar cell unit according to claim 1, The film-type solar cell is a perovskite-type solar cell, The non-film type solar cell is a crystalline silicon solar cell.

4. A solar cell unit maintenance system for performing maintenance on the solar cell unit according to claim 1, characterized in that: The maintenance system comprises: an infrared imaging unit that captures an infrared image of a surface of the film-type solar cell located in a power generation region; and The control unit controls the operation of the winding mechanism based on the image captured by the infrared imaging unit.

5. The solar cell unit maintenance system according to claim 4, The control unit determines whether the abnormal heating area of ​​the film-type solar cell exceeds a preset abnormal heating area threshold based on the infrared image captured by the infrared camera unit, and controls the winding mechanism to replace the film-type solar cell located in the power generation area when it is determined that the abnormal heating area exceeds the abnormal heating area threshold. The winding mechanism includes a first housing for storing the unused film-type solar cell. The solar cell unit maintenance system further includes a sensor for measuring the temperature and humidity inside the first housing. The control unit determines whether the temperature inside the first shell exceeds 50°C and the humidity inside the first shell exceeds 50% based on the measurement results of the sensor, and if it is determined that the temperature inside the first shell exceeds 50°C and the humidity inside the first shell exceeds 50%, the control unit notifies the fact of the excess.

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