JP4859486B2 - Potting material inspection device, potting material defect inspection method, and solar cell panel manufacturing method - Google Patents

Description

  The present invention relates to a defect inspection method for a solar cell, and more particularly to a defect inspection method for a potting material filled in a terminal box of a solar cell panel.

  A solar cell system that generates power using sunlight is known. In the solar cell power generation system, a plurality of solar cell panels are installed and used on the roof of a house.

  In each solar panel, the power generation section that actually generates power is easily damaged by the ingress of moisture and dust from the outside, so the surface is usually a glass substrate and the back side is covered and sealed with a backsheet or the like for protection Has been. The electric power generated by the power generation unit is taken out by connecting an extraction wiring to the power generation unit, drawing it out through an opening provided in the back sheet, and electrically connecting it to an external cable.

  Here, a terminal box is arranged in the opening so that the connection portion between the extraction wiring and the external cable is also protected from the ingress of moisture and dust. Inside the terminal box, the lead-out wiring and the external cable are electrically connected, and the inside of the terminal box is sealed by filling with a potting material.

  As described above, as a technique for arranging a terminal box on a solar cell panel and electrically connecting an external cable and a lead-out wiring inside the terminal box, for example, those disclosed in Patent Documents 1 and 2 can be cited. It is done.

  That is, Patent Document 1 describes that a terminal box is disposed on the back surface opposite to the lighting surface of each solar cell module laid so as to be substantially flush with each other. Has been.

  Further, Patent Document 2 discloses a plurality of relay terminals provided with a connection portion in which an electrode material is electrically connected inside a housing having an insertion port through which an electrode material for output extraction of a solar cell is inserted. And a terminal box that constitutes an output part of a solar cell module in which a single or a plurality of bypass diodes connected between these relay terminals are arranged. It also describes that a potting material is injected into the housing.

  By the way, resin is mainly used for the potting material filled in the terminal box. That is, a potting material is formed by injecting a gel-like resin into the terminal box and drying and curing it.

  Here, when the injected potting material has defects such as poor filling or bubbles opened to the atmosphere side, the wiring inside the terminal box may be exposed to the air at the defective portion. When the wiring is exposed, insulation failure may occur when the inside of the terminal box is exposed to a wet state, which may reduce reliability. Therefore, after the potting material is filled and cured, an inspection is performed as to whether there are any defects such as bubbles.

  The defect inspection of the potting material has been performed by visual inspection with human eyes. For example, Patent Document 3 describes that bubbles appear in silicon gel and the bubbles are confirmed by visual observation.

  However, in general, the potting material is semi-transparent and reflects incident light nonuniformly, and it is difficult to visually distinguish between a defective portion and a normal portion. Moreover, even if the potting material is changed to an opaque material, the situation in which it is difficult to visually distinguish the defective portion from the normal portion due to the reflected light on the surface remains unchanged. Therefore, a skillful technique is required to detect defects such as bubbles in the visual inspection. That is, quantitative inspection was difficult. In addition, it takes time to inspect a large-area solar cell panel because it is extracted from the production line and inspected. It has been desired to provide a technique that does not require time for inspection and can perform quantitative inspection.

  In relation to the above, Patent Document 4 discloses an apparatus for inspecting a filling state of a potting material. That is, Patent Document 4 has an inspection device for inspecting the filling state of the resin after the discharging operation in a potting device that places an element on a transport tape and discharges and seals resin on a predetermined portion of the element. The inspection device is disposed on the front side or the back side of the transport tape, and the light emitting means and the light receiving means disposed opposite to each other on the front and back sides of the transport tape, depending on the filling of the resin. A mask member that has a mask portion that prevents light leakage from a hole that is set so as not to fill the gap, and a mask member that has an opening portion corresponding to a resin-filled portion serving as a portion to be inspected. A featured potting device is disclosed.

However, in any of the above-mentioned documents, there is no description about the defect inspection of the potting material filled in the terminal box of the solar cell panel.
JP-A-9-223538 Japanese Patent Application Laid-Open No. 2001-119058 Japanese Patent Laid-Open No. 2000-234993 Japanese Patent Laid-Open No. 2003-243431

  That is, an object of the present invention is to provide a potting material inspection apparatus and a potting material defect inspection method capable of quantitatively inspecting a potting material defect.

  Another object of the present invention is to provide a potting material inspection apparatus and a potting material defect inspection method capable of quantitatively inspecting a defect of a potting material filled in a terminal box of a solar cell panel.

  Still another object of the present invention is to provide a potting material inspection apparatus and a potting material defect inspection method capable of performing a defect inspection of a potting material in a short time, and to identify a defective solar cell panel. .

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the best mode for carrying out the invention. These numbers and symbols are added in parentheses in order to clarify the correspondence between the description of the claims and the best mode for carrying out the invention. However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.

  The potting material inspection apparatus (1) according to the present invention inspects for defects in the potting material (4) filled in the terminal box (3) of the solar cell panel (2). An illumination unit (5) that irradiates illumination light onto the surface of the filled potting material (4) obliquely from at least two directions, and a camera that photographs the surface of the potting material (4) irradiated with the illumination light ( 6) and an image processing device (7) that processes an image photographed by the camera (6) and detects a defect of the potting material (4). The image processing device (7) detects a defect of the potting material (4) by image analysis in the image.

  Here, the image processing device (7) detects the defect of the potting material by detecting the bright spot (8) whose luminance is higher than the surroundings in the image. Moreover, the defect is a defect with poor filling opened on the outside air side surface of the potting material (4).

According to the above configuration, even when the defect shape cannot be recognized from the image, the defect of the potting material (4) can be detected by detecting the bright spot. As a result of analyzing the image obtained by irradiating illumination light obliquely from above and analyzing the image of the surface thereof, the present inventors have found that a bright spot is generated at the interface on the incident direction side of the illumination light in the defective portion. However, the bright spot may occur other than the defective portion. In general, defects often take the shape of open bubbles or round mortar-shaped recesses with a cross section, that is, defects with poor filling opened to the outside air side. Therefore, by irradiating illumination light from at least two directions, For this defect, at least two bright spots corresponding to the irradiation direction are generated. By utilizing this, it is possible to eliminate detection of bright spots caused by factors other than defects. Therefore, the defect of the potting material (4) can be detected with high accuracy.
The bright spot (8) can be detected by comparing the luminance. If a computer or the like is used as the image processing device (7) for comparing the luminance, quantitative inspection can be performed instead of visual inspection. Also, the time required for the inspection can be shortened.

In the potting material test apparatus (1) according to the present invention, the illumination unit (5) is irradiated with the illumination light on the surface of the at least two directions or Lapo potting material (4), the image processing apparatus (7) is irradiated It is preferable to determine that a defect exists when a bright spot corresponding to the direction of is generated .

Illumination light is emitted from at least two directions, and when a bright spot corresponding to the direction of irradiation is generated, it is determined that a defect is present, thereby more reliably detecting a bright spot caused by a factor other than a defect. Can be eliminated. That is, the defect can be detected with higher accuracy.

  In the potting material inspection apparatus (1) according to the present invention, the illumination unit (5) has an angle between the incident direction of the illumination light and the main surface plane direction of the potting material (4) to be 30 ° to 80 °. Further, it is preferable to irradiate the illumination light.

  In the potting material inspection apparatus (1) according to the present invention, the image processing apparatus (7) detects the bright spot (8) in the image based on the intensity of the luminance of the blue (B) component.

  By detecting the bright spot (8) based on the luminance intensity of the blue (B) component, it is possible to prevent the bright spot from being generated due to factors other than defects. As a cause of the bright spot generated other than the defect, there is a reflection of irradiation light by a metal wiring or the like provided at the bottom of the terminal box. Since light on the short wavelength side like the blue (B) component is easily scattered at the time of reflection, the amount reflected in the direction of the camera (6) is small. Therefore, it is possible to selectively detect the bright spot (8) due to the defect while eliminating the detection of the bright spot that occurs outside the defect.

  In the potting material inspection apparatus (1) according to the present invention, the illumination unit (5) preferably emits white illumination light from an LED (Lighting Emitting Diode). Also, LED white light is suitable because it has a sufficient amount of light and is stable and has a long life.

  In the potting material inspection apparatus (1) according to the present invention, it is preferable that the illumination unit (5) emits monochromatic illumination light mainly composed of the blue color of the LED.

  In the potting material inspection apparatus (1) according to the present invention, the illumination unit (5) includes a first light source (9) and a second light source (10). A 1st light source (9) irradiates the white illumination light of LED. A 2nd light source (10) irradiates the monochromatic illumination light which mainly made blue of LED.

  In the potting material inspection apparatus (1) according to the present invention, a region to be image-analyzed is divided into a plurality of precisions based on the ease of occurrence of a defect depending on the position to be inspected and the degree of influence on the sealing structure when the defect occurs. It is preferable to set the priority order to reduce the load of image processing and improve the processing speed.

  The potting material inspection device (1) according to the present invention further includes a transport device (11) for transporting the solar cell panel (2) and a transport control device (12) for grasping the substrate ID for identifying the solar cell panel (2). And). The image processing device (7) outputs the defect detection result of the potting material (4) to the output device (13) in association with the ID information.

  The potting material defect inspection method according to the present invention is a potting material defect inspection method for inspecting defects of the potting material (4) filled in the terminal box (3) of the solar cell panel (2). An illumination step (step S30) of irradiating illumination light onto the surface of the filled potting material (4) obliquely from at least two directions, and a step of photographing the surface of the potting material (4) irradiated with the illumination light (Step S40), a step of image analysis of an image obtained by photographing, a defect detection step (step S70) of detecting a defect of the potting material (4) based on a detection result of the image analysis step, Is provided.

  The step of analyzing the image preferably includes a bright spot detecting step (step S60) for detecting a bright spot (8) whose luminance is higher than that of the surrounding area. Moreover, when performing image analysis, it is preferable to perform image analysis on a defect with poor filling opened on the outside air surface of the potting material (4).

Bright In the potting material defect inspection method according to the present invention, in the illumination step (S30), and irradiating the illumination light on the surface of the at least two directions or we before Symbol potting material, in the step of image analysis, corresponding to the direction of the irradiation It is preferable to determine that a defect exists when a dot occurs .

  In the potting material defect inspection method according to the present invention, in the illumination step (S30), when irradiating the illumination light, the angle formed between the incident direction of the illumination light and the main surface plane of the potting material (4) is 30 ° to 30 °. A range of 80 ° is preferable.

  In the potting material defect inspection method according to the present invention, it is preferable that the bright spot (8) is detected based on the brightness of the blue (B) component in the image in the bright spot detecting step (S60).

  In the potting material defect inspection method according to the present invention, in the illumination step (S30), it is preferable to irradiate white illumination light by an LED (Lighting Emitting Diode).

  In the potting material defect inspection method according to the present invention, in the illumination step (S30), it is preferable to irradiate monochromatic illumination light mainly composed of blue of the LED.

  In the potting material defect inspection method according to the present invention, the illumination light is emitted from the first light source (9) and the second light source (10) in the illumination step (S30). A 1st light source (9) irradiates the white illumination light of LED. A 2nd light source (10) irradiates the monochromatic illumination light which mainly made blue of LED.

  In the potting material defect inspection method according to the present invention, in the image analysis step, it is preferable to prioritize the image analysis accuracy according to the inspection target position, reduce the burden of image processing, and improve the processing speed.

  The potting defect inspection method according to the present invention further includes a step of transporting the solar cell panel (2) (step S10), a step of grasping the substrate ID of the solar cell panel (2) to be transported (step S100), And a step (step S90) of outputting the defect detection result in the defect detection step (S70) to the output device (13) in association with the ID information.

  In the method for manufacturing a solar cell panel according to the present invention, a step (step S01) of forming a solar cell film (15) on the non-light-receiving surface side of the transparent substrate (2), and an adhesive sheet (16 ) To cover with the back sheet (17) (step S02), the terminal box (3) is attached to the non-light-receiving surface side of the back sheet (17), and is connected to the solar cell film (15) A step of wiring the inside of the terminal box (3) so that the wiring (18) is electrically connected to the external cable (19) inside the terminal box (3) (step S03), and the inside of the terminal box (3) Filling the potting material (4) into the step (step S04), inspecting the potting material defect by the potting material defect inspection method (step S05), and the potting material 4) based on the test results, comprising the steps of selecting a solar panel (2) (step S06), the.

  According to the present invention, a potting material inspection apparatus and a potting material defect inspection method capable of quantitatively performing a potting material defect inspection are provided.

  According to the present invention, there is further provided a potting material inspection apparatus and a potting material defect inspection method capable of quantitatively inspecting a defect of a potting material filled in a terminal box of a solar cell panel.

  According to the present invention, there is further provided a potting material inspection apparatus and a potting material defect inspection method capable of performing a defect inspection of a potting material in a short time, and a defective panel is specified.

(First embodiment)
(Constitution)
This embodiment will be described with reference to the drawings. A potting material inspection apparatus 1 according to the present embodiment is an apparatus for inspecting a defect of a potting material 4 filled in a terminal box 3 of a solar cell panel 2. First, the structure of the solar cell panel 2 to be inspected will be described.

  FIG. 1 is a diagram schematically showing a cross-sectional configuration of the solar cell panel 2. The solar cell panel 2 includes a transparent substrate 14, a solar cell 15, an adhesive sheet 16, and a back sheet 17.

  The solar cell 15 is provided on the light receiving surface side of the transparent substrate 14. For example, in the case of a thin-film solar battery, the solar battery 15 is formed by connecting a plurality of strip-shaped solar battery cells 36 such that the long sides are adjacent to each other. Here, each photovoltaic cell 36 is connected in series. The solar cell 15 is covered with a back sheet 17 through an adhesive sheet 16. In addition, the solar cell 15 is connected to an extraction wiring 18 for extracting the generated electric power to the outside. The back sheet 17 is provided with an opening 20 for taking out the extraction wiring to the outside. A terminal box 3 is provided on the upper side (light receiving surface side) of the opening 20. Inside the terminal box 3, the extraction wiring 18 drawn out to the outside through the opening 20 and the external cable 19 are wired so as to be electrically connected. The inside of the terminal box 3 is filled with a potting material 4 so that the connection portion of the wiring is not exposed.

  As the potting material 4, a silicone resin or the like is used. The potting material 4 is filled by injecting a translucent gel-like material into the terminal box 3 and then drying and curing. Thereby, the wiring inside the terminal box 3 is protected. Here, when the gel-like potting material is injected, bubbles may be generated. If the bubbles are not deaerated even during drying, the wiring inside the terminal box 3 may be exposed. That is, it becomes a defect. FIG. 2 is a cross-sectional view showing the shape of the defect due to the bubbles. When small bubbles are present on the surface of the potting material as shown in FIG. 2 (a), the wiring is still covered with the potting material 4, but the large size as shown in FIG. 2 (b). If bubbles remain, the wiring part may be exposed.

  As described above, the location where the bubble portion is opened and the shape of the concave portion having a round mortar shape is difficult to distinguish by visual inspection or the like. The potting material inspection apparatus 1 according to the present invention is an apparatus for detecting bubbles (defects) having such a size as to expose the wiring as described above. Many of the defective portions of the potting material (4) other than the defects in which bubbles are opened are relatively easy to identify, and a pattern recognition method by image analysis can be used without the invention of the present invention described below. It can be used together. Moreover, it can test | inspect by visual inspection etc. The configuration of the potting material inspection apparatus 1 according to the present embodiment will be described below. FIG. 3A is a diagram showing a schematic configuration of the potting material inspection apparatus 1 according to the present embodiment, and FIG. 3B is a block diagram thereof. The potting material inspection device 1 includes an LED illumination (illumination unit) 5, a CCD camera (camera) 6, an image processing device 7, a display device (output device) 13, and a transport device 11 (shown only in FIG. 3A). And a conveyance control device 12. Each configuration will be described in detail below.

  The transport device 11 transports the solar battery panel 2 while holding it in the horizontal direction. At this time, the solar cell panel 2 to be conveyed has the terminal box 3 side (light receiving surface side) on the upper side.

  The transport control device 12 controls the operation of the transport device 11. The conveyance control device 12 stops the solar cell panel 2 when the solar cell panel 2 reaches the inspection position. Moreover, the conveyance control apparatus 12 grasps | ascertains board | substrate ID which is the information which identifies the solar cell panel 2. FIG.

  The LED illumination 5 emits white illumination light from an LED that has a sufficient amount of light and has a long life and is stable.

  Four LED lights 5 are provided. In FIG. 3B, only two of them are drawn. Any of the LED lights 5 is fixed above the transport device 11. The four LED illuminations 5 emit illumination light from four different directions obliquely upward to the terminal box 3 of the solar cell panel 2 that has reached the inspection position and is stationary or decelerated to a state in which the conveyance speed can be inspected. It is arranged to irradiate. At this time, the upper side of the terminal box 3 is not covered with a lid or the like. That is, the surface of the potting material 4 is exposed, and the surface of the potting material 4 is illuminated by the illumination light.

  The CCD camera 6 is provided above the transport device 11. The CCD camera 6 is arranged so as to photograph the surface of the potting material 4 illuminated by the LED illumination 5 from above. The CCD camera 6 is connected to the image processing device 7 and transmits the image to the captured image processing device 7. As shown in FIG. 3A, the portion illuminated by the LED illumination 5 and photographed by the CCD camera 6 may be covered and shielded by an external light shielding cylinder. By being shielded from light, the influence of external light is suppressed.

  FIG. 4 is a diagram for explaining the manner in which the illumination light is irradiated by the LED illumination 5 and the CCD camera 6 captures the surface of the potting material 4 as viewed from the side. Since it is a side view, only two of the four LED lights 5 are shown. The two LED lights 5 are arranged so as to illuminate the surface of the potting material 4 so as to face each other from obliquely above the surface of the potting material 4. The remaining two LED lights 5 are respectively arranged on the back side and the front side in the direction perpendicular to the paper surface. The CCD camera 6 images the surface of the potting material 4 irradiated with illumination light from directly above.

  Here, the angle (incident angle θ) formed between the incident direction of the irradiation light and the surface plane 21 of the potting material 4 is preferably in the range of 30 ° to 80 °, more preferably 60 °. When the illumination light is incident in such a range, when the irradiation light is reflected at the defect portion, the probability that the illumination light is reflected directly upward (in the direction of the CCD camera 6) is increased, and a bright spot described later is detected. The accuracy is better.

  Next, the image processing device 7 will be described. The image processing device 7 realizes a function of processing an image acquired from the CCD camera 6 and detecting a defect. The image processing apparatus 7 is a computer having a CPU and a memory, and realizes its function by an installed computer program. FIG. 5 is a diagram conceptually showing the configuration of the image processing apparatus 7. The image processing apparatus 7 includes an image correction unit 71, a bright spot detection unit 72, a pattern matching unit 73, and an output unit 74 as computer programs.

  The image correction unit 71 performs correction processing on the acquired image before actually detecting a bright spot. Specifically, the position of the terminal box 3 is detected. Further, the angle of the terminal box 3 is corrected. The correction of the angle is performed because the terminal box 3 may be displaced in the transport direction. By these processes, the surface of the potting material 4, that is, the inspection area is specified. In addition, image averaging processing may be performed as necessary. In general, the CCD camera 6 captures a single shot image with an instantaneous image of, for example, 1/30 second per frame. However, there may be a case where there is a problem in image processing due to lack of clarity due to noise. By performing image averaging, a plurality of instantaneous images are obtained continuously to obtain an averaged image. Noise is eliminated and a clear image is obtained, which is advantageous for image processing.

  Here, in specifying the region to be inspected, only the portion that needs to be inspected may be selected instead of the entire surface of the potting material 4. Also, a plurality of areas may be provided, and priorities may be given from areas with high necessity. Examples of the region having a high inspection priority include (1) a region where a step is generated in the wiring in the terminal box 3, and (2) a region where the core wire of the external cable is exposed. Hereinafter, with reference to FIG. 6, a region having a high priority will be described in detail while showing the configuration of the wiring inside the terminal box 3.

  FIG. 6 is a top view schematically showing wiring inside the terminal box 3 as an example, and also shows an XX cross-sectional view. The internal structure of the terminal box 3 is not limited to this. A plurality of metal plates 23 are provided inside the terminal box 3. A take-out wiring 18 (not shown in FIG. 6) drawn through the opening 20 (not shown in FIG. 6) is connected to a metal plate 23A disposed in the center at the connection portion 22. . Connection at the connection portion 22 is performed by soldering. The metal plate 23 </ b> A disposed in the center is connected to the metal plates 23 </ b> B at the four corners via the lead wires 25 and other metal plates 23. External cables 19 are inserted from the four corners of the terminal box 3. The core wire 24 is exposed at the inserted tip. A step is generated in the portion where the core wire 24 is exposed from the external cable 19. The tips of the core wires 24 are connected to the metal plates 23 at the four corners.

  In the wiring as described above, when performing defect inspection of the potting material 4, the region that should be given the highest priority is a region (Zone 1) where there are steps and the core wires 24 at the four corners are exposed. In Zone 1, since a step is generated, there is a case where the step portion is not followed when the potting material is injected. If the potting material does not follow the step, bubbles are generated, which may cause a defect. Further, since the core wire 24 is in the terminal box corner and is thin, bubbles are generated below the core wire 24 during potting filling, and the bubbles may float on the surface and become a defect. Therefore, it is necessary to preferentially inspect the area where the core wire 24 is exposed.

  A region having a higher priority after Zone 1 is an area (Zone 2) in which the metal plate 23 is disposed. Since the metal plate 23 electrically connects the take-out wiring 18 and the external cable 19, the occurrence of bubbles on the metal plate 23 resulting in defects may hinder the electrical connection. However, since there is no step at the center of the terminal box and it is not a thin wire like the core wire 24, it is not necessary to give priority to Zone1.

  In this way, the area filled with the potting material 4 is divided into a high-priority area and a low-priority area, and inspection is performed according to the priority order, thereby reducing the burden required for image processing to a minimum. This can improve throughput and reduce costs. Here, following the priority order includes lowering a threshold for detecting a bright spot, which will be described later, in an area having a higher priority order.

  Refer to FIG. 5 again. The bright spot detection unit 72 extracts only the luminance of the blue component (B) for the inspection area selected as described above. Subsequently, a point (bright spot 8) where the luminance is stronger than the surroundings is detected. For example, the bright spot 8 can be detected by setting a threshold value in advance as shown in FIG. 7 and detecting a point exceeding the threshold value.

  The reason for extracting the luminance of the blue component (B) will be described. A bright spot may be detected by factors other than defects. For example, the irradiation light is reflected by the metal plate 23 disposed at the bottom of the terminal box 3 and may be detected as a bright spot by the CCD camera 6 detecting this. In the present embodiment, the brightness of the blue component (B) is compared to detect the bright spot, thereby eliminating the influence of the bright spot due to factors other than the defect to be detected. This is because the light of the blue component (B) is a short wavelength light and is easily scattered when reflected. Since the blue component (B) light is scattered even if it enters the metal plate 23, it is difficult to be reflected toward the CCD camera 6. Therefore, it is difficult for the CCD camera 6 to take a picture and it is difficult to become a bright spot. On the other hand, since the defective part is located on the surface of the potting material 4 or on the vicinity of the surface, the CCD camera 6 can take an image of these bright spots even if scattered.

What is clearly determined as a defect from the shape may be determined as a defect by image analysis. A plurality of bright spots 8 are used for those whose shape is difficult to recognize.
The pattern matching unit 73 performs pattern matching of the detected bright spot 8 and confirms whether it is due to a defect or a factor other than a defect. The pattern matching will be described with reference to FIG. FIG. 7 is a view of defects due to bubbles as viewed from above. Moreover, the line distribution by the XX line of luminance is also shown. In FIG. 7, the direction of the arrow is the direction of incidence of illumination light. At the defect interface on the side corresponding to the incident direction of the illumination light, the luminance is higher than the surroundings. In addition, the luminance is low inside the defect. Thus, the point where the luminance is higher than the surrounding area is the bright spot 8. In the present embodiment, since the illumination light is incident from four directions, four bright spots 8 corresponding to the four directions are generated. Using this, the pattern matching unit 73 determines that a defect exists when the four bright spots 8 corresponding to the four incident directions are generated. On the other hand, if a bright spot 8 is generated but is present alone or has a plurality of bright spots but does not correspond to the incident direction, the bright spot 8 is caused by factors other than defects. to decide.

  The pattern matching unit 73 calculates the distance between the detected bright spots 8. The bright spot 8 resulting from the defect is generated at the interface portion of the defect. In addition, defects caused by bubbles are mostly hemispherical recesses on the surface of the potting material 4. The image taken by the CCD camera appears in a substantially circular shape. Therefore, the defect size can be obtained by calculating the distance between the bright spots 8. By obtaining the size of the defect, it is possible to detect only the defect having a predetermined size or larger. Specifically, a distance between two facing bright spots among the four bright spots 8 is obtained. Then, as shown in FIG. 2A, when “a / 2” is shorter than the thickness b of the potting material 4 as the distance a between the bright spots 8, the size is large enough to expose the wiring. Judge that it is not a defect. On the other hand, as shown in FIG. 2B, when “a / 2> b”, it is determined that the wiring is exposed. In this way, the pattern matching unit 73 detects a defect having a predetermined size or more.

  The output unit 74 accesses the transport control device 12 and acquires the substrate ID of the solar battery panel 2 that has detected the defect. The acquired substrate ID is displayed on the display device 13 in association with the defect detection result by the pattern matching unit 73. When a defect is detected in the pattern matching unit 73, an alarm device (not shown) may be driven to issue an alarm. In addition, an image obtained by extracting only the luminance of the blue (B) component by the bright spot detection unit 72 or an image acquired by the image correction unit 71 may be displayed on the display device 13. Since the image of the potting 4 filled in the terminal box 3 is displayed, the operator can easily find the defect visually, and the potting portion of the target panel where the defect is confirmed can be corrected.

  The display device 13 is operated by the output unit 74 and displays a result of defect inspection by the image processing device 7.

(Operation method)
Subsequently, the potting material defect inspection method according to the present embodiment will be described. FIG. 8 is a flowchart showing an operation flow of the potting material defect inspection method. The potting material defect inspection method includes a step of transporting a solar cell panel (step S10), a step of grasping a transport position of the solar cell panel (step S100), a step of stopping or decelerating the transport (step S20), and irradiating illumination light. Step (step S30), photographing step (step S40), image capturing step (step S50), image correcting step (step S55), bright spot detecting step (step S60), defect detecting step (Step S70), obtaining a substrate ID (Step S80), and outputting (Step S90). Details of each step will be described below.

Step S10; Transport of Solar Cell Panel First, the solar cell panel 2 is transported by the transport device 11. The solar cell panel 2 is the one after the potting material 4 is filled in the terminal box 3 and dried. The solar cell panel 2 is conveyed while being held parallel to the horizontal direction with the terminal box 3 side facing upward.

Step S100: Grasping the transport position of the solar cell panel The transport controller 12 grasps the position of the solar cell panel 2 to be transported. The transport control device 12 also grasps the substrate ID that identifies the solar cell panel 2.

Step S20: Stop of transport When the solar battery panel 2 is transported to a predetermined position (position where photographing is performed by the CCD camera 6), the transport controller 12 sets the solar battery panel 2 to a speed at which the solar battery panel 2 can be stopped or inspected. Decelerate.

Step S30: Irradiation of illumination light Subsequently, the LED illumination 5 emits illumination light so that the surface of the potting material 4 filled in the terminal box 3 is illuminated obliquely from above.

Step S40: Photographing Further, the CCD camera 6 photographs the surface of the potting material 4. The CCD camera 6 transmits the captured image to the image processing device 7.

Step S50: Image Capture The image processing device 7 captures an image from the CCD camera 6 and performs the following operations.

Step S55: Correction of Image The image correction unit 71 corrects the acquired image. That is, as described above, the position of the terminal box 3 is detected, and the angle corresponding to the positional relationship between the terminal box 3 and the image is corrected. Then, the inspection area is specified. At this time, if necessary, it is divided into a plurality of areas according to the priority of inspection.

Step S60; Detection of Bright Spots Subsequently, the bright spot detection unit 72 extracts only the luminance of the blue component (B) for the inspection area specified in step S55. Then, a point (bright spot 8) where the brightness is stronger than the surroundings is detected. The bright spot 8 can be detected by, for example, setting a threshold value in advance and detecting a point exceeding the threshold value.

Step S70: Detecting a defect Further, the pattern matching unit 73 performs a pattern matching of the detected bright spot 8 to confirm whether the defect is caused by a defect or a factor other than a defect. The pattern matching unit 73 notifies the output unit 74 of the defect detection result.

Step S80; Acquisition of Substrate ID When the output unit 74 acquires the detection result from the pattern matching unit 73, the output unit 74 accesses the transport control device 12 and acquires the substrate ID of the solar cell panel 2 that has detected the defect.

Step S90: Output The output unit 74 further displays the detection result acquired from the pattern matching unit 73 on the display device 13 in association with the substrate ID. At this time, if it is a detection result that a defect exists, an alarm device (not shown) may be driven to issue an alarm.

  Thus, a series of operations of the potting material defect inspection method according to the present embodiment is completed.

(Solar cell panel manufacturing method)
This invention is also a manufacturing method of the solar cell panel using the potting material defect inspection method. The manufacturing method of the solar cell panel according to the present embodiment will be described in detail below. FIG. 9 is a flowchart of a method for manufacturing a solar cell panel using a thin film type solar cell as an example. The solar cell panel manufacturing method includes a step of forming a solar cell film (step S01), a step of covering with a back sheet (step S02), a step of wiring the inside of the terminal box (step S03), and a step of filling a potting material ( Step S04), inspecting the defect of the potting material (Step S05), and selecting the solar cell panel (Step S06). Details of each step will be described in detail below. Here, an example in which a glass substrate as the transparent substrate 14 is used and a single layer amorphous silicon thin film solar cell is used as the solar cell film 15 thereon will be described. 10-13 is the schematic which shows embodiment of the manufacturing method of the solar cell panel of this invention.

Step S01: Step of forming solar cell film (1) FIG. 10 (a):
A soda float glass substrate (1.4 m × 1.1 m × plate thickness: 4 mm) is used as the transparent substrate 14. It is desirable that the end face of the substrate is corner chamfered or rounded to prevent breakage.
(2) FIG. 10 (b):
A transparent electrode film mainly composed of a tin oxide film (SnO 2) is formed as the transparent conductive layer 151 at a temperature of about 500 ° C. to about 500 ° C. using a thermal CVD apparatus. At this time, a texture with appropriate irregularities is formed on the surface of the transparent electrode film. As the transparent conductive layer 151, in addition to the transparent electrode film, an alkali barrier film (not shown) may be formed between the transparent substrate 14 and the transparent electrode film. As the alkali barrier film, a silicon oxide film (SiO 2) is formed at a temperature of about 500 ° C. in a thermal CVD apparatus with a thickness of 50 to 150 nm.
(3) FIG. 10 (c):
Thereafter, the transparent substrate 14 is set on the XY table, and the first harmonic (1064 nm) of the laser diode-pumped YAG laser is incident from the film surface side of the transparent electrode film as indicated by the arrow in the figure. Pulse oscillation: Adjusting the laser power so as to be suitable for the processing speed as 5 to 20 kHz, the width of the transparent electrode film so as to form the groove 30 in the direction perpendicular to the series connection direction of the solar cells. Laser etching into 6-10 mm strips.
(4) FIG. 10 (d):
Using a plasma CVD apparatus, a p-layer film / i-layer film / n-layer film made of an amorphous silicon thin film as the photoelectric conversion layer 152 is sequentially formed at a reduced pressure atmosphere of 30 to 150 Pa and about 200 ° C. The photoelectric conversion layer 152 is formed on the transparent conductive layer 151 using SiH4 gas and H2 gas as main raw materials. The p-layer, i-layer, and n-layer are stacked in this order from the sunlight incident side. In this embodiment, the photoelectric conversion layer 152 is a p-layer: B-doped amorphous SiC and a film thickness of 10 to 30 nm, an i-layer: amorphous Si and a film thickness of 250-350 nm, and an n-layer: p-doped microcrystalline Si. The film thickness is 30 to 50 nm. A buffer layer may be provided between the p layer film and the i layer film in order to improve the interface characteristics.
(5) FIG. 10 (e)
The transparent substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is incident from the film surface side of the photoelectric conversion layer 3 as indicated by the arrow in the figure. Pulse oscillation: 10 to 20 kHz, the laser power is adjusted so as to be suitable for the processing speed, and laser etching is performed so as to form the groove 31 on the lateral side of the laser etching line of the transparent conductive layer 151 about 100 to 150 μm. .
(6) FIG. 11 (a)
As the back electrode layer 153, an Ag film and a Ti film are sequentially formed by a sputtering apparatus at about 150 ° C. in a reduced pressure atmosphere. In this embodiment, the back electrode layer 153 is an Ag film: 200 to 500 nm, and a Ti film having a high anticorrosive effect: 10 to 20 nm is laminated in this order as a protective film. For the purpose of reducing contact resistance between the n-layer and the back electrode layer 153 and improving light reflection, a GZO (Ga-doped ZnO film) film thickness between the photoelectric conversion layer 152 and the back electrode layer 153: 50 to 100 nm, sputtering apparatus May be provided by forming a film.
(7) FIG. 11 (b)
The transparent substrate 14 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is incident from the transparent substrate 14 side as indicated by the arrow in the figure, so that the laser light is photoelectrically generated. The back electrode layer 153 is exploded and removed using the high gas vapor pressure that is absorbed by the conversion layer 152 and generated at this time. Pulse oscillation: 1 to 10 kHz, the laser power is adjusted so as to be suitable for the processing speed, and laser etching is performed so that the groove 32 is formed on the lateral side of the laser etching line of the transparent conductive layer 151 about 250 μm to 400 μm. .
(8) FIG. 11 (c)
The power generation region is divided to eliminate the influence that the serial connection portion due to laser etching is likely to be short-circuited at the film edge around the substrate edge. The transparent substrate 14 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is incident from the transparent substrate 14 side, so that the laser light is transmitted through the transparent conductive layer 151 and the photoelectric conversion layer 152. The back electrode layer 153 is exploded and removed using the high gas vapor pressure generated at this time. The laser power is adjusted so that the processing speed is appropriate for pulse oscillation: 1 to 10 kHz, and laser etching is performed at a position of 5 to 15 mm from the end of the transparent substrate 14 so as to form an X-direction insulating groove. At this time, no Y-direction insulating groove is provided.
(9) FIG. 12 (a)
Since the laminated film around the transparent substrate 14 (peripheral region 34) has a step and is easy to peel off in order to ensure a healthy adhesion / seal surface with the back sheet through EVA or the like in the subsequent process, Remove. First, polishing removal is performed on the back electrode layer 153 / photoelectric conversion layer 152 / transparent conductive layer 151 at 5-15 mm from the edge of the substrate and closer to the substrate edge than the insulating groove 30 provided in the step of FIG. Do. Polishing debris and abrasive grains were removed by washing the transparent substrate 14.

Step S02: Step of covering with back sheet (10) FIG. 12 (b)
Subsequently, the solar cell film 15 is covered with the back sheet 17. At this time, the back sheet 17 is provided with an opening 20 at a position to be the terminal box 3 mounting portion. Then, the extraction wiring 18 is pulled out from the opening 20. A plurality of layers of insulating material are provided in the opening 20 portion to suppress intrusion of moisture and the like from the outside. The extraction wiring 18 is connected to one end of the photovoltaic power generation cell 5 arranged in series and the other end of the photovoltaic power generation cell 5. Note that the lead-out wiring 18 is a copper foil, and one that is covered with an insulating sheet wider than the width of the copper foil is used in order to prevent a short circuit with each part.
After the take-out wiring 18 and the like are arranged at predetermined positions, an adhesive sheet 16 made of EVA (ethylene vinyl acetate copolymer) or the like is arranged so as to cover the entire solar cell film 15 and not protrude from the transparent substrate 14. On the EVA, the back sheet 17 having a high waterproof effect is installed. In this embodiment, the back sheet 17 has a three-layer structure of PTE sheet / AL foil / PET sheet so that the waterproof and moisture proof effect is high. The EVA sheet is placed in a predetermined position until the back sheet 17 is deaerated with a laminator in a reduced-pressure atmosphere and pressed at about 150 to 160 ° C., and EVA is crosslinked and brought into close contact.

Step S03: Step of wiring inside the terminal box (11) FIG. 13 (a)
The terminal box 3 is attached to the back side of the solar cell panel 2 with an adhesive. The extraction wiring 18 and the external cable 19 inserted in the terminal box 3 are connected by soldering or the like.

Step S04: Step of filling the potting material (12) FIG. 13 (b)
Further, a sealing material (potting material) is injected into the terminal box 3 and dried. The potting material 4 is a silicone-based sealing resin, and used was a mixture of a main agent and a curing agent, defoamed, and gelled. Drying is preferably performed for several hours.

Step S05: Inspection of Defects When the potting material 4 is dried, the potting material inspection apparatus 1 described above detects defects in the potting material.

Step S06: Screening of solar cell panels Based on the detection results of defects in the potting material, only those in which no defects were detected are selected. In the selected product, the upper part of the terminal box 3 is sealed with a lid. Thereby, the solar cell panel 2 is completed. On the other hand, the product in which the defect is detected is removed from the production line. And it can complete as the solar cell panel 2 by performing the repair process which embeds a defective part with a potting material again.

  As described above, according to the present embodiment, the potting material 4 is irradiated with illumination light from an obliquely upward direction, and this is photographed with a camera to detect a bright spot, whereby bubbles in the potting material 4 are detected. The resulting defect can be detected. Since the detection and analysis of the bright spot can be performed by the image processing device 7, the accuracy is better than the visual inspection. Further, since in-line inspection can be performed, throughput is improved.

  Further, by performing illumination from four directions obliquely above the potting material 4, four bright spots can be generated for one defect. Therefore, by analyzing the pattern of the bright spot 8 obtained by the image processing apparatus 7, it can be determined whether the bright spot 8 is derived from a defect or a dummy bright spot. That is, since a bright spot that is not originally related to a defect is not detected, the accuracy of defect detection is further improved.

  Further, according to the present embodiment, when detecting a bright spot, the bright spot is detected by comparing the luminance of the blue (B) component, so that the detection of bright spots due to factors other than defects is suppressed. Can do. That is, the defect can be detected with higher accuracy.

In the present embodiment, the case where four LED lights 5 are provided has been described. However, it is not always necessary that four LED lights 5 are provided, and at least two LED lights may be provided. Even when only two LED lights 5 are provided, dummy bright spots 8 can be eliminated by the above-described pattern analysis. In addition, the lighting cost is reduced. That is, as the number of LED lights 5 is increased, the accuracy of defect detection by the above-described pattern analysis can be improved, but the advantage is a trade-off with the illumination cost.
LED white light is suitable because it has a sufficient amount of light and is stable and has a long life, but it is not necessary to limit to LED. Similarly, a lamp that satisfies the same performance in terms of light quantity, stability, and life can be used. For example, a xenon lamp can also be used.

  In the present embodiment, the conveyance control device 12 is described as detecting the defect by decelerating the solar cell panel 2 so that the solar cell panel 2 can be stopped or inspected, but in a state where the solar cell panel 2 is moved, You may comprise so that the LED illumination 5 and CCD camera 5 may also be moved. Thus, by matching the LED illumination 5 and the CCD camera 5 with the movement of the solar cell panel 2, the solar cell panel 2 does not need to be stationary or decelerated for inspection, and the throughput of the production line is further improved.

(Second Embodiment)
Next, the second embodiment will be described. In the first embodiment, LED illumination emits white illumination light as the illumination unit 5, whereas in this embodiment, the type of illumination light emitted by the illumination unit 5 is devised. The configuration other than the illumination light is the same as that of the first embodiment, and a description thereof will be omitted.

  Although the illumination part 5 is LED illumination 5, it is comprised so that the monochromatic light mainly having the blue wavelength of B (450-480 nm) may be irradiated as illumination light. In addition, the LED illumination 5 should just be provided at least 2 units | set similarly to 1st Embodiment. The operation of the image processing device 7 when detecting a bright spot is the same as that in the first embodiment.

  By irradiating the blue monochromatic light of B (450 to 480 nm) with the illumination unit 5, it is possible to eliminate the influence of the background and make the image clearer. This is because blue monochromatic light is short-wavelength light and has a large amount of scattering upon reflection. Even if the blue monochromatic light is reflected by the wiring member such as the metal plate 23 arranged at the bottom of the potting material 4, the amount of the scattered light is large, so that the reflected light is not easily reflected toward the CCD camera 6. Therefore, it is difficult for the CCD camera 6 to receive light and it is difficult to become a bright spot. Since the light reflected by the wiring member such as the metal plate 23 is difficult to be detected as the bright spot 8, only the bright spot 8 generated by the surface of the potting material 4 or a defect near the surface can be selectively detected. That is, the accuracy of defect detection is further improved.

(Third embodiment)
Subsequently, a third embodiment will be described. In the second embodiment, the case where the illumination unit 5 emits blue monochromatic light has been described. However, the illumination unit 5 is further devised in the present embodiment. In addition, about structures other than LED illumination 5, it is the same as that of 1st, 2nd embodiment, and abbreviate | omits description.

  The illumination unit 5 includes a first light source 9 and a second light source 10. The 1st light source 9 is LED illumination which irradiates the white illumination light similar to 1st Embodiment. On the other hand, the 2nd light source 10 is LED illumination which irradiates the blue monochromatic light similar to 2nd Embodiment. The illumination unit 5 includes one first light source 9 and one second light source 19 as a set, and at least two sets are provided as a whole. The illuminating unit 5 illuminates the potting material from obliquely upward as in the first and second embodiments.

  According to the present embodiment, by using blue monochromatic light, as in the second embodiment, the influence of reflection by the wiring member such as the metal plate 23 is suppressed, and the accuracy of detecting the bright spot 8 is further increased. Can be improved. Furthermore, by adding white illumination light, the intensity of the brightness of the image taken by the CCD camera 6 can be increased as a whole. By increasing the intensity of the brightness as a whole, the bright spot 8 can be detected with higher accuracy and the positional relationship with the terminal box 3 can be analyzed with higher accuracy. That is, the accuracy of defect detection is further improved.

It is a figure which shows roughly the cross-sectional structure of a solar cell panel. It is a figure explaining the magnitude | size of a defect. It is a schematic block diagram of the potting material test | inspection apparatus which concerns on this invention. It is a block diagram which shows the structure of the potting material test | inspection apparatus which concerns on this invention. It is a side view explaining the incident direction of an illumination part. FIG. 4 is a diagram showing a data flow in the image processing apparatus 7. It is a figure which shows roughly the wiring inside a terminal box. It is a figure explaining the method of the luminescent spot detection derived from a defect. It is a flowchart which shows operation | movement of the potting material defect inspection method. It is a flowchart which shows operation | movement of the manufacturing method of a solar cell panel. It is a figure explaining the manufacturing method of a solar cell panel. It is a figure explaining the manufacturing method of a solar cell panel. It is a figure explaining the manufacturing method of a solar cell panel. It is a figure explaining the manufacturing method of a solar cell panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Potting material test | inspection apparatus 2 Solar cell panel 3 Terminal box 4 Potting material 5 Illumination part 6 Camera 7 Image processing apparatus 8 Bright spot 9 1st light source 10 2nd light source 11 Conveyance apparatus 12 Conveyance control apparatus 13 Output apparatus 14 Transparent substrate DESCRIPTION OF SYMBOLS 15 Solar cell 151 Transparent conductive layer 152 Photoelectric conversion layer 153 Back surface electrode layer 16 Adhesive sheet 17 Back sheet 18 Extraction wiring 19 External cable 20 Opening 21 Surface plane 22 Connection part 23 Metal plate 24 Core wire 25 Lead wire 30 Groove 31 Groove 32 Groove 34 Peripheral area 36 Solar cell

Claims (15)

A potting material inspection device for inspecting a defect of a potting material filled in a terminal box of a solar cell panel,
An illumination unit that irradiates illumination light on the surface of the filled potting material obliquely from at least two directions;
A camera for photographing the surface of the potting material irradiated with the illumination light;
An image processing device that processes an image captured by the camera and detects defects in the potting material;
Comprising
The said image processing apparatus is a potting material inspection apparatus which detects the defect of the said potting material by image analysis by detecting the bright spot whose brightness | luminance is higher than the periphery in the said image. The potting material inspection apparatus according to claim 1 ,
The illumination unit irradiates the illumination light on the surface of the at least two directions or we before Symbol potting material,
The image processing apparatus is a potting material inspection apparatus that determines that a defect exists when a bright spot corresponding to an irradiation direction is generated . The potting material inspection apparatus according to claim 1 or 2 ,
The illumination unit is a potting material inspection apparatus that irradiates the illumination light so that an angle formed between an incident direction of the illumination light and a main surface plane direction of the potting material is 30 ° to 80 °. The potting material inspection apparatus according to any one of claims 1 to 3 ,
The image processing apparatus is a potting material inspection apparatus that detects the bright spot based on a luminance intensity of a blue (B) component in the image. The potting material inspection apparatus according to any one of claims 1 to 4 ,
The illumination unit irradiates white illumination light of an LED (Lighting Emitting Diode) ,
Alternatively, the illumination unit irradiates monochromatic illumination light mainly composed of blue of the LED,
Alternatively, the illumination unit includes a first light source and a second light source,
The first light source emits white illumination light of an LED,
The second light source is a potting material inspection apparatus that emits monochromatic illumination light mainly composed of blue LED . The potting material inspection apparatus according to any one of claims 1 to 5 ,
A potting material inspection apparatus that prioritizes image analysis accuracy according to the inspection target position, reduces the burden of image processing, and improves processing speed. The potting material inspection apparatus according to any one of claims 1 to 6 ,
Furthermore,
A transport device for transporting the solar cell panel;
A transport control device for grasping a substrate ID identifying the solar cell panel;
Comprising
The image processing apparatus is a potting material inspection apparatus that outputs a detection result of the defect of the potting material in association with the ID information to an output device. A potting material defect inspection method for inspecting defects of a potting material filled in a terminal box of a solar cell panel,
An illumination step of irradiating illumination light on the surface of the filled potting material obliquely from at least two directions;
Photographing the surface of the potting material irradiated with the illumination light;
Image analysis of an image obtained by shooting ;
Based on the detection result of the image analysis step, a defect detection step of detecting a defect of the potting material,
Equipped with,
The potting material defect inspection method, wherein the image analyzing step includes a bright spot detecting step of detecting a bright spot having a brightness higher than that of the surrounding area . The potting material defect inspection method according to claim 8 ,
In the illuminating step, irradiating the illumination light on the surface of the at least two directions or we before Symbol potting material,
A potting material defect inspection method for determining that a defect exists when a bright spot corresponding to an irradiation direction is generated in the image analysis step . The potting material defect inspection method according to claim 8 or 9 ,
In the illuminating step, the potting material defect inspection method wherein an angle formed between an incident direction of the illumination light and a main surface plane of the potting material is 30 to 80 ° when irradiating the illumination light. The potting material defect inspection method according to any one of claims 8 to 10 ,
A potting material defect inspection method for detecting the bright spot based on a luminance of a blue (B) component in the image in the bright spot detecting step. A potting material defect inspection method according to any one of claims 8 to 11 ,
In the illuminating step, white illumination light is emitted by a light emitting diode (LED) .
Or, in the illumination step, irradiates a monochromatic illumination light mainly composed of blue of the LED,
Alternatively, in the illumination step, the illumination light is emitted from a first light source and a second light source,
The first light source emits white illumination light of an LED,
The said 2nd light source is a potting material defect inspection method which irradiates the monochromatic illumination light which mainly made blue of LED . The potting material defect inspection method according to any one of claims 8 to 12 ,
In the image analysis step, a potting material defect inspection method that prioritizes image analysis accuracy according to an inspection target position, reduces a burden of image processing, and improves a processing speed. The potting material defect inspection method according to any one of claims 8 to 13 ,
Furthermore,
Conveying the solar cell panel;
A panel position grasping step for grasping position information indicating the position of the solar cell panel conveyed by the conveying device in association with a substrate ID identifying the solar cell panel;
Obtaining ID information for identifying the solar cell panel that has been detected based on the position information;
Outputting a defect detection result in the defect detection step in association with the ID information to an output device;
A potting material defect inspection method comprising: Forming a solar cell film on the non-light-receiving surface side of the transparent substrate;
Covering the solar cell film with a back sheet through an adhesive sheet;
A terminal box is attached to the non-light-receiving surface side of the back sheet, and the inside of the terminal box is wired so that the extraction wiring connected to the solar cell film is electrically connected to an external cable inside the terminal box. And steps to
Filling a potting material inside the terminal box;
A step of inspecting a defect of the filled potting material by the potting material defect inspection method according to any one of claims 8 to 14 ;
Selecting the solar cell panel based on the inspection result of the potting material;
The manufacturing method of the solar cell panel which comprised.

Images