Solar cell unit and solar cell unit maintenance system

Abstract

To provide a solar cell unit and a maintenance system thereof that allows for the combined use of film-type solar cells and non-film-type solar cells and allows for easy replacement of the film-type solar cells.SOLUTION: A solar cell unit 2 includes a film-type solar cell 21 arranged on the light incident side, a non-film-type solar cell 22 arranged on the side opposite to the light incident side of the film-type solar cell 21, and a reeling mechanism 23 that reels up the film-type solar cell 21. The film-type solar cell 21 is made slidable relative to the non-film-type solar cell 22 by the winding mechanism 23.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] As solar cells, crystalline silicon-based solar cells and perovskite solar cells are widely known. Crystalline silicon-based solar cells have high efficiency in absorbing light energy and converting it into electrical energy, and high performance and reliability. Therefore, they are used by being attached to the roofs and outer walls of buildings. In addition, as described in Patent Document 1 below, they are also installed and used on the roofs and sides of vehicles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, crystalline silicon-based solar cells have the drawback that the light energy absorption efficiency decreases when they are made thinner, so it is necessary to ensure a practical thickness. In addition, since crystalline silicon-based solar cells have a hard glass component, it is not easy to make them thin and flexible. For this reason, it is difficult to make crystalline silicon-based solar cells into film-type solar cells. On the other hand, perovskite solar cells have a large light energy absorption coefficient and can maintain high conversion efficiency even when made thinner. Furthermore, perovskite solar cells are lighter, thinner, and more flexible than crystalline silicon-based solar cells, so a flexible film-type solar cell can be easily realized.

[0005] Recently, a tandem structure in which these solar cells are stacked has attracted attention so that film-type solar cells typified by perovskite solar cells and non-film-type solar cells typified by crystalline silicon solar cells can be used in combination. However, since perovskite solar cells are easily affected by light, heat, and moisture, they have lower durability than crystalline silicon solar cells. For this reason, in the above-described tandem structure, there is a problem that it is difficult to replace the perovskite solar cell at the same timing as the crystalline silicon solar cell.

[0006] 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 thereof that can easily replace a film-type solar cell while using the film-type solar cell and the non-film-type solar cell in combination.

Means for Solving the Problems

[0007] The solar cell unit according to the present invention includes 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 for winding the film-type solar cell. The film-type solar cell is slidable with respect to the non-film-type solar cell by the winding mechanism.

[0008] In the solar cell unit according to the present invention, since it includes 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, the film-type solar cell can absorb short-wavelength light energy and convert it into electrical energy, and the non-film-type solar cell can absorb long-wavelength light energy and convert it into electrical energy. As a result, 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 increased. Further, since the film-type solar cell is slidable relative to the non-film-type solar cell by a winding mechanism, the film-type solar cell can be easily replaced by winding up the film-type solar cell. As a result, while using the film-type solar cell and the non-film-type solar cell in combination, the film-type solar cell can be easily replaced at an appropriate timing.

[0009] In the solar cell unit according to the present invention, it is preferable that the winding mechanism includes a first case for storing the unused film-type solar cell, a second case disposed away from the first case so as to provide a power generation region between the first case and the second case, and a winding portion for feeding out the unused film-type solar cell stored in the first case to the power generation region and storing the film-type solar cell fed out to the power generation region in the second case. In this way, the unused film-type solar cell can be easily fed out, and the used film-type solar cell can be easily stored. Therefore, the replacement of the film-type solar cell can be easily realized.

[0010] In the solar cell unit according to the present invention, it is preferable that 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 combined use of the film-type solar cell and the non-film-type solar cell can be easily realized, and the cost of the solar cell unit can be reduced.

[0011] Moreover, 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 includes an infrared imaging unit that captures an infrared image of the surface of the film-type solar cell in the power generation region, and a control unit that controls the operation of the winding mechanism based on the image captured by the infrared imaging unit.

[0012] In the maintenance system for a solar cell unit according to the present invention, since the control unit controls the operation of the winding mechanism based on the infrared image captured by the infrared imaging unit, when it is determined that the film-type solar cell needs to be replaced, the replacement can be easily performed at an appropriate timing, so that the power generation efficiency of the solar cell unit can be maintained.

[0013] In the maintenance system for a solar cell unit according to the present invention, the control unit determines whether or not the abnormal heat generation area of the film-type solar cell exceeds a preset abnormal heat generation area threshold value based on the infrared image captured by the infrared imaging unit. When it is determined that the abnormal heat generation area exceeds the abnormal heat generation area threshold value, it is preferable to control the winding mechanism to replace the film-type solar cell in the power generation region. In this way, when the control unit determines that the abnormal heat generation area exceeds the abnormal heat generation area threshold value, by controlling the winding mechanism to replace the film-type solar cell in the power generation region, the replacement of the film-type solar cell can be easily performed at an appropriate timing.

[0014] The maintenance system for a solar cell unit according to the present invention further includes a sensor that measures the temperature and humidity inside the first case. The control unit determines whether or not the temperature inside the first case exceeds 50°C and the humidity inside the first case exceeds 50% based on the measurement results of the sensor. When it is determined that the temperature inside the first case exceeds 50°C and the humidity inside the first case exceeds 50%, it is preferable to notify that fact. In this way, deterioration of the film-type solar cell due to heat and moisture can be prevented.

Effects of the Invention

[0015] According to the present invention, while using a film-type solar cell and a non-film-type solar cell in combination, the film-type solar cell can be easily replaced.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of a solar cell unit and a maintenance system of a solar cell according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and the overlapping description thereof will be omitted.

[0018] FIG. 1 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 according to the present embodiment is a system for performing maintenance on 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.

[0019] [Regarding the solar cell unit] As shown in FIG. 1, the solar cell unit 2 is removably attached to, for example, the side surface 101 of the vehicle 10. 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 up the film-type solar cell 21. In the present embodiment, the "light incident side" means the side on which sunlight is incident.

[0020] The film-type solar cell 21 is thin and flexible, that is, a so-called flexible solar cell. Examples of the film-type solar cell 21 include a perovskite solar cell and an amorphous silicon solar cell. Hereinafter, an example of a perovskite solar cell will be given to describe the structure of the film-type solar cell 21.

[0021] FIG. 2 is a schematic cross-sectional view showing the structure of the film-type solar cell, and FIG. 3 is a schematic plan view showing the film-type solar cell. As shown in FIGS. 2 and 3, the film-type solar cell 21 is formed by alternately arranging a plurality of cells 21A and a plurality of insulating portions 21B along the longitudinal direction of the film-type solar cell 21. The cell 21A has a base material 211, a transparent electrode 212, a hole transport layer 213, a photoelectric layer 214, an electron transport layer 215, and an electrode 216. The base material 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 base material 211 and the transparent electrode 212, and the electrode 216 are exposed from the resin sealing layer 217. Further, barrier films 218 are provided on both sides (the light incident side and the opposite side thereof) of the resin sealing layer 217.

[0022] The transparent electrode 212 of each 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 cell 21A is electrically connected to, for example, a positive terminal (not shown) provided on the winding drive shaft 262.

[0023] The base material 211 is, for example, transparent glass or polyethylene terephthalate (PET), the transparent electrode 212 is ITO (Indium Tin Oxide) which is a mixture of indium oxide and tin oxide, the hole transport layer 213 is Spiro-OMeTAD, the optoelectronic layer 214 is a CH3NH3PbI3 perovskite material, the electron transport layer 215 is titanium oxide, and the electrode 216 is formed by Au respectively.

[0024] On the other hand, the insulating part 21B is a part where the perovskite material is not applied or printed, and is formed only by, for example, the barrier film 218, and is integrated with the adjacent cell 21A.

[0025] 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 already used in a well-known solar cell panel, the description of its structure and the like is omitted.

[0026] The winding mechanism 23 has a first case 24 for storing the unused film type solar cell 21, a second case 25 disposed away from the first case 24 so as to provide a power generation region S between the first case 24, and a winding part 26 for feeding out the unused film type solar cell 21 stored in the first case 24 to the power generation region S and storing the film type solar cell 21 fed out to the power generation region S in the second case 25.

[0027] The first case 24 is formed in a box shape by, for example, an aluminum material and is fixed to one end of the mounting plate 27. Inside the first case 24, in addition to the unused film type solar cell 21, a part of the components of the winding part 26 is also stored. The unused film type solar cell 21 is pivotally supported by a support shaft 261 (described later) in the first case 24 in a state of being wound in a roll shape. Further, an opening for taking out the stored film type solar cell 21 to the outside of the first case 24 is arranged on the wall surface of the first case 24 facing the second case 25.

[0028] The second case 25 is formed in a box shape, for example, by an aluminum material, and is fixed to the other end of the mounting plate 27 so as to face the first case 24. And the space between the first case 24 and the second case 25 constitutes the above-described power generation region S. Inside the second case 25, a winding drive shaft 262 is housed. Also, corresponding to the opening of the first case 24, an opening for taking the film type solar cell 21 into the inside of the case is also arranged on the wall surface of the second case 25 facing the first case 24.

[0029] The mounting plate 27 is formed of a metal material such as aluminum, for example, and serves to fix the first case 24, the second case 25, and the non-film type solar cell 22, and also serves as a mounting member when the solar cell unit 2 is attached to the side surface 101 of the vehicle 10.

[0030] The winding part 26 includes a support shaft 261 disposed inside the first case 24, a winding drive shaft 262 disposed inside the second case 25, a first free roll 263, a second free roll 264, and a third free roll 265 disposed in order from the support shaft 261 toward the winding drive shaft 262, and a tension drive shaft 266 close to the second free roll 264.

[0031] The support shaft 261 supports the unused film type solar cell 21 wound in a roll shape in a rotatable state. For example, it has a cylindrical shape, one end is fixed to the inner wall of the first case 24, and the other end is a free end. The unused film type solar cell 21 is formed in a long shape having a certain width and is wound around a hollow winding core. The unused film type solar cell 21 wound in this way can be housed in the first case 24 by inserting the free end of the support shaft 261 into the hole of the winding core.

[0032] The first free roll 263, the second free roll 264, and the third free roll 265 are housed inside the first case 24, and are provided in a triangular shape so as to adjust the tension of the unused film-type solar cell 21. For example, as shown in FIG. 1, the first free roll 263 and the third free roll 265 are linearly arranged in the vertical direction of the vehicle 10, and the second free roll 264 is arranged closer to the vehicle 10 side than the first free roll 263 and the third free roll 265.

[0033] The tension drive shaft 266 is arranged at a position close to the second free roll 264, and applies tension to the film-type solar cell 21 so as to feed out the unused film-type solar cell 21 passing through the second free roll 264 without slack. This tension drive shaft 266 is rotationally driven in the direction opposite to the feeding direction of the film-type solar cell 21 by an electric motor (not shown).

[0034] The take-up drive shaft 262 is rotationally driven by an electric motor (not shown), thereby feeding out the unused film-type solar cell 21 housed in the first case 24 to the power generation area S, and taking up the film-type solar cell 21 fed out to the power generation area S.

[0035] As shown in FIG. 1, 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. This non-film-type solar cell 22 is fixed to the mounting plate 27.

[0036] In the present embodiment, the film-type solar cell 21 and the non-film-type solar cell 22 do not have a structure integrated by lamination, but have independent structures. Therefore, the film-type solar cell 21 and the non-film-type solar cell 22 may be arranged so as to be close to each other, or may be arranged in a separated state with a certain distance therebetween.

[0037] According to the winding mechanism 23 of the present embodiment, when the winding drive shaft 262 is rotationally driven as shown by the arrow, the winding core fixed to the winding drive shaft 262 rotates in the direction shown by the arrow. As a result, the film-type solar cell 21 in the power generation region S is pulled toward the second case 25 side and wound around the winding core fixed to the winding drive shaft 262. At the same time, the unused film-type solar cell 21 stored in the first case 24 is fed out to the power generation region S.

[0038] Note that the film-type solar cell 21 and the non-film-type solar cell 22 may be formed as a two-terminal type connected in series, or may be formed as a four-terminal type for separately extracting electricity from the film-type solar cell 21 and the non-film-type solar cell 22. Considering that the non-film-type solar cell 22 can be retrofitted, it is preferably formed as a four-terminal type.

[0039] In the solar cell unit 2 configured as described above, since the film-type solar cell 21 in the power generation region S is disposed on the light incident side with respect to the non-film-type solar cell 22, the film-type solar cell 21 absorbs short-wavelength light energy and converts it into electrical energy, and the non-film-type solar cell 22 can absorb long-wavelength light energy and convert it into electrical energy. That is, with respect to sunlight, the film-type solar cell 21 generates power as a top cell, and the non-film-type solar cell 22 generates power as a bottom cell. By using the film-type solar cell 21 and the non-film-type solar cell 22 in combination in this way, light of a wide range of wavelengths can be utilized, and the power generation efficiency of the solar cell unit 2 can be improved.

[0040] Further, since the film-type solar cell 21 is slidable with respect to the non-film-type solar cell 22 by the winding mechanism 23, the film-type solar cell 21 can be easily replaced by winding up the film-type solar cell 21. Therefore, it becomes possible to separately replace the film-type solar cell 21 and the non-film-type solar cell 22 having different durabilities, 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 in combination.

[0041] Perovskite solar cells are greatly affected by moisture in addition to light and heat. Therefore, when attaching the solar cell unit 2 having a perovskite solar cell to the vehicle 10, it is necessary to devise the arrangement positions of the first case 24 and the second case 25 so as to suppress the influence of moisture.

[0042] For example, as shown in FIG. 4, when the solar cell unit 2 is attached to the upper surface 102 of the vehicle 10, the first case 24 is preferably arranged at the front part of the vehicle 10, and the second case 25 is preferably arranged at the rear part of the vehicle 10. This is because, for example, when water droplets adhere to the upper surface 102 of the vehicle 10, when the vehicle 10 travels, the adhered water droplets move from the front to the rear of the vehicle 10. Therefore, by arranging the unused perovskite solar cell at the front of the vehicle and the used perovskite solar cell at the rear of the vehicle, respectively, deterioration of the unused perovskite solar cell due to moisture can be suppressed, and the occurrence of hot spots (described later) due to the deterioration can be prevented.

[0043] On the other hand, when the solar cell unit 2 is attached to the side surface 101 of the vehicle 10, the first case 24 is preferably arranged above the vehicle 10, and the second case 25 is preferably 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 above to below the vehicle 10 by gravity. Therefore, by arranging the unused perovskite solar cell above the vehicle and the used perovskite solar cell below the vehicle, respectively, deterioration of the unused perovskite solar cell due to moisture can be suppressed, and the occurrence of hot spots due to the deterioration can be prevented.

[0044] [Regarding the maintenance system of the solar cell unit] As described above, the maintenance system 1 of the solar cell unit according to 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 in the power generation area S, and outputs it to the control unit 3. This drone 4 is communicably connected to the control unit 3, captures an infrared image of the surface of the film-type solar cell 21 during power generation, and transmits the captured infrared image to the control unit 3 together with related position information and the like.

[0045] The control unit 3 is constituted by, for example, a microcomputer combining a CPU (Central Processing Unit) that executes operations, a ROM (Read Only Memory) as a secondary storage device that records a program for operations, and a RAM (Random Access Memory) as a temporary storage device that stores the progress of operations and temporary control variables. The overall control of the maintenance system 1 of the solar cell unit is performed by executing the stored program.

[0046] For example, the control unit 3 controls the operation timing and operation time of the winding drive shaft 262 and the tension drive shaft 266 with respect to the winding mechanism 23 communicably connected thereto. Further, the control unit 3 controls the automatic navigation, imaging timing, imaging time, etc. of the drone 4.

[0047] When generating power using a film-type solar cell 21 such as a perovskite solar cell, hot spots may occur. A hot spot is the occurrence of a high electrical resistance part in a part of the film-type solar cell 21 (for example, a part of a perovskite solar cell), resulting in abnormal heat generation. The causes of hot spot generation include external factors such as the attachment of bird droppings and fallen leaves, and internal factors such as poor solder wiring and cell cracking due to aging deterioration. When a hot spot occurs, it causes a decrease in the power generation amount, so it is necessary to replace the film-type solar cell 21.

[0048] In order to inspect the presence or absence of hot spots, in this embodiment, the film-type solar cell 21 in the power generation area S is aerially photographed from a high position using the drone 4 equipped with the above-described infrared camera, and the presence or absence of hot spots is confirmed based on the thermal image (infrared image) of the film-type solar cell 21. For example, when the vehicle is stopped, the inspection is performed using the drone with the solar cell unit 2 operating. In that case, since the inspection of each solar cell unit 2 can be performed on a plurality of stopped vehicles by one drone in a short time, the maintenance efficiency can be improved.

[0049] At that time, based on the infrared image captured by the drone 4, the control unit 3 determines whether or not the abnormal heat generation area of the film-type solar cell 21 in the power generation area S exceeds a preset abnormal heat generation area threshold value. Specifically, the control unit 3 calculates the abnormal heat generation area of the film-type solar cell 21 in the power generation area S based on the infrared image of the film-type solar cell 21, and compares the result of the calculated abnormal heat generation area with the preset abnormal heat generation area threshold value to determine whether or not the abnormal heat generation area exceeds the abnormal heat generation area threshold value.

[0050] And when it is determined that the abnormal heat generation area exceeds the abnormal heat generation area threshold value, the control unit 3 controls the winding mechanism 23 to replace the film-type solar cell 21 in the power generation area S. Specifically, when it is determined that the abnormal heat generation area exceeds the abnormal heat generation area threshold value, the control unit 3 transmits a control command to the winding drive shaft 262 and the tension drive shaft 266, and rotationally drives the winding drive shaft 262 and the tension drive shaft 266, respectively.

[0051] When the winding drive shaft 262 and the tension drive shaft 266 are rotationally driven respectively, the film-type solar cell 21 in the power generation area S (that is, the film-type solar cell 21 having a hot spot) slides with respect to the non-film-type solar cell 22 and is stored in the second case 25. At the same time, the unused film-type solar cell 21 stored in the first case 24 is fed out to the power generation area S. Thereby, the film-type solar cell 21 in the power generation area S is replaced.

[0052] 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 winding mechanism. That is, the film type solar cell 21 in the power generation area S is continuously used for power generation without being replaced.

[0053] In addition, the infrared image captured by the drone 4 also includes the position information of the hot spot. The control unit 3 can specify the position of the hot spot based on the position information of the hot spot. Further, the control unit 3 determines whether to replace the entire film type solar cell 21 in the power generation area S or to replace it partially based on the specified position of the hot spot.

[0054] For example, when the hot spot exists over the entire film type solar cell 21 in the power generation area S, the control unit 3 determines that it is necessary to replace the entire film type solar cell 21 in the power generation area S, and transmits a control command to the winding drive shaft 262 and the tension drive shaft 266 to control the rotation speed and rotation time of the winding drive shaft 262 and the tension drive shaft 266 so that the entire film type solar cell 21 in the power generation area S can be replaced.

[0055] On the other hand, for example, when the hot spot exists not over the entire film type solar cell 21 in the power generation area S but on the second case 25 side, the control unit 3 determines to replace only the second case 25 side where the hot spot exists instead of the entire film type solar cell 21 in the power generation area S. At this time, the control unit 3 controls the rotation speed and rotation time of the winding drive shaft 262 and the tension drive shaft 266 so that only the second case 25 side where the hot spot exists among the film type solar cells 21 in the power generation area S can be replaced. By diverting the usable film type solar cells 21 in this way, the cost of the solar cell unit 2 can be reduced.

[0056] In the maintenance system of the solar cell unit according to this embodiment, the control unit 3 determines whether or not 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 3 controls the winding mechanism 23 to replace the film-type solar cell 21 in the power generation area S. By doing so, it is possible to easily grasp the presence or absence of hot spots in the film-type solar cell 21, and when they occur, 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 hot spots and maintain the power generation efficiency of the solar cell unit 2.

[0057] In addition, as shown in FIGS. 1 and 4, it is preferable that the maintenance system 1 of the solar cell unit of this embodiment further includes a sensor 5 that measures the temperature and humidity inside the first case 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 case 24 respectively, and transmits the measured results to the control unit 3.

[0058] The control unit 3 determines whether or not the temperature inside the first case 24 exceeds a preset temperature threshold and the humidity inside the first case 24 exceeds a preset humidity threshold based on the measurement results of the sensor 5. In this 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 or not the temperature inside the first case 24 exceeds 50°C and the humidity inside the first case 24 exceeds 50% respectively.

[0059] When it is determined that the temperature inside the first case 24 exceeds 50°C and the humidity inside the first case 24 exceeds 50% respectively, the control unit 3 notifies the driver of the vehicle 10 or / and the administrator of the maintenance system 1 of the solar cell unit, etc. of the fact that it has exceeded. As a method of notification, for example, it can be considered to display it on a display provided in the driver's cab of the vehicle 10 or the system management room, or to notify the driver and the administrator via sound.

[0060] By doing so, the driver or the administrator can grasp that the temperature and humidity inside the first case 24 have exceeded their respective threshold values. Therefore, by taking measures to lower the temperature and humidity inside the first case 24 (for example, the driver temporarily parks the vehicle 10 in the shade) until a certain period of time (for example, 15 minutes) has elapsed since the notification, it is possible to prevent deterioration of the unused film-type solar cell 21 stored in the first case 24.

[0061] If no measures are taken to lower the temperature and humidity inside the first case 24 and a certain period of time (for example, 15 minutes) has elapsed since the notification, the unused film-type solar cell 21 stored in the first case 24 will be deteriorated and thus will be discarded. In this case, the deteriorated unused film-type solar cell 21 may be replaced with a new one.

[0062] As described above, perovskite solar cells are easily affected not only by light but also by heat (temperature) and moisture (humidity). For example, CH3NH3PbI3, which is a perovskite material, reacts with water to become PbI2. As a result, the photoelectric layer of the film-type solar cell decomposes, so the film-type solar cell deteriorates and discolors (turns yellow). Therefore, the inventor of the present application investigated the influence of temperature and humidity on the film-type solar cell 21.

[0063] [Example 1] First, the inventor of the present application created a plurality of flat samples having the structure of the above-described film-type solar cell 21, divided the created 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, the presence or absence of discoloration of the samples in each group was confirmed. As a result, the samples related to the high-temperature endurance test were discolored, while the samples related to the low-temperature endurance test were hardly discolored. From this result, it was found that perovskite solar cells have relatively weak heat resistance.

[0064] [Example 2] In addition, the inventor of the present application created a plurality of samples having the structure of the above-described film-type solar cell 21, and examined the presence or absence of discoloration of the samples due to changes in humidity in an environment at a temperature of 50°C. More specifically, a flat sample having the same structure as the film-type solar cell 21 was produced, and after measuring the initial lightness (L), hue (a), and chroma (b) of the produced sample, the sample was left for 15 minutes under six conditions of humidity, namely 50%, 55%, 60%, 65%, 70%, and 85% in an environment at a temperature of 50°C. Thereafter, the lightness (L), hue (a), and chroma (b) of each sample were measured again, and the differences (i.e., ΔL, Δa, Δb) between the initial lightness, hue, and chroma of the sample and the lightness, hue, and chroma of the sample after being left under the above-described conditions were determined, and ΔE was calculated using the following formula (1). Table 1 shows the test conditions and the results thereof.

[0065] [Number]

[0066] Note that the lightness (L), hue (a), and chroma (b) of each sample are standards determined by the International Commission on Illumination for representing colors, and are measured using devices such as a spectrophotometer or a color difference meter. The measurement was performed based on JIS Z 8781 using a spectrophotometer (CM-M6, manufactured by Konica Minolta Japan, Inc.) to irradiate 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.

[0067] [Table 1]

[0068] From the results in Table 1, it was found 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 discoloration. 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, deterioration of the film-type solar cell 21 caused by temperature and moisture can be suppressed.

[0069] Also, from the results in Table 1, it was found that by taking measures to lower the temperature and humidity within 15 minutes after the temperature becomes 50°C or lower and the humidity becomes 50% or lower, deterioration of the film-type solar cell 21 can be prevented. In addition, by providing a barrier film or the like on the film-type solar cell 21, the time until deterioration can be extended.

[0070] As described above, the embodiments of the present invention have been described in detail. However, 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.

[0071] For example, in the above-described embodiment, the solar cell unit 2 has been described by taking the example of being attached to the outer surface of the vehicle 10, but it may be attached to a train, a building, or the like. Further, on the premise of not affecting the power generation of the solar cell unit 2, the shape of the film-type solar cell 21 may be changed or a color may be imparted so that the film-type solar cell 21 further has an advertising or promotional function.

Explanation of Reference Numerals

[0072] 1: Maintenance system of solar cell unit, 2: Solar cell unit, 3: Control unit, 4: Drone (infrared imaging unit), 5: Sensor, 10: Vehicle, 21: Film-type solar cell, 21A: Cell, 21B: Insulating portion, 22: Non-film-type solar cell, 23: Rewinding mechanism, 24: First case, 25: Second case, 26: Rewinding portion, 27: Mounting plate, 101: Side surface, 102: Upper surface, 211: Base material, 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 roll, 264: Second free roll, 265: Third free roll, 266: Driving shaft for tension

Claims

1. 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, A winding mechanism for winding up the film-type solar cell, Comprising, The film-type solar cell is slidable with respect to the non-film-type solar cell by the winding mechanism, and the solar cell unit is characterized in that.

2. The winding mechanism is, A first case for storing the unused film-type solar cell, A second case disposed away from the first case so as to provide a power generation region between the first case and the first case, A winding unit that feeds out the unused film-type solar cell stored in the first case to the power generation region and stores the film-type solar cell fed out to the power generation region in the second case, The solar cell unit according to claim 1, which has.

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

4. A maintenance system for a solar cell unit that performs maintenance on the solar cell unit according to claim 1, An infrared imaging unit that images an infrared image of the surface of the film-type solar cell in the power generation region, A control unit that controls the operation of the winding mechanism based on the image captured by the infrared imaging unit, A maintenance system for a solar cell unit, characterized by comprising.

5. The control unit determines whether or not 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, and when it is determined that the abnormal heating area exceeds the abnormal heating area threshold, the winding mechanism is controlled to replace the film-type solar cell in the power generation region. The winding mechanism has a first case for storing the unused film-type solar cell, The maintenance system of the solar cell unit further includes a sensor for measuring the temperature and humidity inside the first case, The control unit determines whether or not the temperature inside the first case exceeds 50°C and the humidity inside the first case exceeds 50% based on the measurement results of the sensor. When it is determined that the temperature inside the first case exceeds 50°C and the humidity inside the first case exceeds 50%, the maintenance system for the solar cell unit according to claim 4 notifies that fact.

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