JP5230153B2 - Method for manufacturing photoelectric conversion device - Google Patents

Description

  The present invention relates to a photoelectric conversion device and a manufacturing method thereof, and more particularly, to a thin film solar cell and a manufacturing method thereof.

  As a photoelectric conversion device in which a photoelectric conversion unit that receives light and extracts electric power on a substrate is formed, for example, a solar cell using a thin film can be given. In the thin film solar cell, a solar cell film formed as a photoelectric conversion unit on a substrate and capable of generating power is hereinafter referred to as a solar cell module. Moreover, what attached the back sheet | seat, the terminal box, the flame | frame, etc. to the solar cell module and hold | maintained environmental resistance is described as a solar cell panel.

  Fig.1 (a) is a top view which shows the structure of a solar cell module. As shown in this figure, the solar cell film 102 is provided on the center side of the substrate 101. The solar cell film 102 is not provided on the peripheral edge of the substrate 101 (hereinafter, the surrounding region 103), and the substrate 101 is exposed. When the solar cell module is made into a panel, a back sheet or the like is attached using an EVA adhesive sheet or the like in order to protect the solar cell film 102 from the use environment. The peripheral region 103 is preferably provided for the purpose of securing a good adhesion / seal surface when the backsheet is disposed. The peripheral region 103 is provided by once forming the solar cell film 102 over the entire surface of the substrate and then polishing and removing the solar cell film 102 at the peripheral edge with blasting or the like. Techniques relating to such surrounding areas are disclosed in, for example, Patent Documents 1 and 2.

  The solar cell film 102 is divided into strips so as to form a plurality of solar cells 107 (photoelectric conversion cells; hereinafter may be simply referred to as cells). The plurality of solar battery cells 107 are electrically connected in series. FIG.1 (b) is sectional drawing which shows the XX cross section of Fig.1 (a). As shown in FIG. 1B, the solar cell film 102 includes a transparent electrode layer 104 provided on the substrate 101, a photoelectric conversion layer 105 provided on the transparent electrode layer 104, and a photoelectric conversion layer 105. And a back electrode layer 106 provided on the substrate. The transparent electrode layer 104 is divided by the transparent electrode layer dividing groove 109 so as to correspond to each solar battery cell 107. The photoelectric conversion layer 105 and the back electrode layer 106 are also divided so as to correspond to the solar cells 107 by grooves. A back electrode layer 106 is buried in a groove dividing the photoelectric conversion layer 105. Thereby, the back electrode layer 106 of one cell 107 is electrically connected to the transparent electrode layer 104 of the adjacent cell 107. With such a configuration, the plurality of cells 107 are electrically connected in series with the adjacent cells 107. Grooves such as the transparent electrode layer dividing groove 109 are formed by laser etching.

  Reference is again made to FIG. Insulating grooves 108 are provided in the vicinity of both ends in the Y direction side of the solar cell film 102 so as to extend in the X direction in the figure. FIG.1 (c) is sectional drawing which shows the YY cross section of Fig.1 (a). As shown in FIG. 1C, the insulating groove 108 is a groove from which the solar cell film 102 has been removed. Since a solar cell is usually installed outdoors, it can be exposed to rain or snow. At this time, it is conceivable that moisture enters from the end of the substrate 101 and the solar cell film 102 is electrically connected to the outside through the moisture. If the solar cell film 102 is electrically connected to the outside, the power generation performance may be deteriorated due to poor insulation or deterioration of the solar cell film 102. The insulating groove 108 is provided to prevent such conduction. This insulating groove 108 is also formed by laser etching.

  Of the region where the solar cell film 102 is provided, the power is actually extracted from the region inside the substrate (side of the substrate) from the insulating groove 108. In this specification, a region where power is actually taken out during power generation is referred to as a power generation region. In addition, the region where the solar cell film remains is distinguished from the power generation region and is described as a solar cell film remaining region (photoelectric conversion unit region).

  A technique related to the insulating groove is described in Patent Document 3. Patent Document 3 describes that an insulating groove is provided so as not to reach the end of the substrate. When the insulating groove reaches the end of the substrate, moisture may enter through the insulating groove from the end of the substrate. According to Patent Document 3, moisture is prevented from entering the insulating groove portion by providing the insulating groove so as not to extend to the end of the substrate.

  By the way, when the present inventors observed the solar cell module in detail, it was found that in the peripheral region 103, fine traces may be formed on the exposed substrate surface.

JP 2000-349325 A Japanese Patent Laid-Open No. 2000-261019 JP 2006-253417 A

  2A and 2B are diagrams showing measurement results of the surface roughness of the surrounding region 103. FIG. Fig.2 (a) has shown the surface roughness of the solar cell module surface along the line A in Fig.1 (a). In order to completely remove the solar cell film 102 from the surrounding region 103 by a polishing process such as blasting, it is preferable that the surface layer of the substrate 101 is slightly cut. At this time, the exposed substrate surface has irregularities of several μm level. FIG. 2B shows the surface roughness of the surface along the line B in FIG. From the result shown in FIG. 2A, there is no significant change in the surface roughness in the surrounding region 103. That is, in the direction parallel to the groove dividing the cell such as the transparent electrode layer dividing groove 109 (Y direction), no significant change is observed in the surface roughness. On the other hand, from the results shown in FIG. 2 (b), it was found that there were portions where the surface was slightly wrinkled.

  FIG. 3 is a plan view schematically showing the observation results of the corners of the solar cell module. The surrounding area 103 is formed so as not to remain by polishing such as blasting, and appears to be uniform at first glance. However, when carefully observed, traces appearing darker (darker) than the surroundings may be observed on the extended lines of the transparent electrode layer dividing grooves 109 and the extended lines of the insulating grooves 108. The position of such a black-looking mark coincided with the drowned portion shown in FIG. Therefore, it was estimated that the mark which looks black was the drowning part shown by FIG.2 (b).

  The present inventors considered that such a mark was caused by a laser irradiated when forming the transparent electrode layer dividing groove 109 and the insulating groove 108. As described above, the transparent electrode layer dividing groove 109 and the insulating groove 108 are formed by laser etching. Usually, at the time of laser etching, the substrate 101 is moved relative to the substrate 101 using an XY table and the etching target film is etched while the laser beam is irradiated. Is irradiated with a laser. At that time, the laser is also applied to the surrounding region 103 (formation scheduled region) corresponding to the extension line of the groove. When the transparent electrode layer dividing groove 109 and the insulating groove 108 are formed, the surface of the substrate 101 is exposed by etching, but the heat generated by being absorbed by the etching target film during laser irradiation also affects the exposed surface state of the substrate 101. End up. As a result, a slight shape change also occurs on the exposed surface of the substrate 101, and in some cases, the substrate 101 itself may be etched. For this reason, even after the surrounding region 103 (scheduled formation region) is formed, a mark that appears black (darker) than the surroundings on the extension line of the transparent electrode layer dividing groove 109 and the extension line of the insulating groove 108, that is, This may be observed.

  When a shape change portion (hereinafter referred to as a laser mark) formed in the surrounding region 103 remains, a gap corresponding to a capillary tube is generated after the solar cell film is covered with a filler such as EVA that adheres a back sheet or the like. This will cause the sealing performance to deteriorate. As a result, moisture penetrates deeper than expected from the side of the substrate 101 due to capillarity, easily reaches the insulating groove 108, and the insulating property is lowered due to the moisture entering the insulating groove 108. There is concern.

  Further, as described above, when the peripheral region 103 is formed, the solar cell film 102 formed on the peripheral portion of the substrate is polished and removed. At this time, there is a concern that laser cracks may trigger micro cracks and chips on the substrate surface. Small cracks and chips formed in the surrounding region 103 also enlarge the region causing the capillary phenomenon, reduce the sealing performance, and may cause moisture intrusion from the side of the substrate 101.

  Therefore, an object of the present invention is to provide a technique capable of maintaining a healthy surface state in the surrounding region 103 and preventing moisture from entering from the end portion of the substrate into the deep portion due to a capillary phenomenon or the like.

  [Means for Solving the Problems] will be described below using the numbers and symbols used in [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 [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers and symbols should not be used for the interpretation of the technical scope of the invention described in [Claims].

  The manufacturing method of the photoelectric conversion apparatus of this invention is a photoelectric conversion unit formation process which forms a photoelectric conversion unit (2) so that it may be divided | segmented into a some photoelectric conversion cell (7) on the main surface of a board | substrate (1). And, after the photoelectric conversion unit forming step, the peripheral region forming step (step S50) for removing the photoelectric conversion unit (2) formed on the peripheral portion of the main surface and forming the peripheral region (3). It has. The photoelectric conversion unit forming step includes a transparent electrode layer forming step (step S10) for forming the transparent electrode layer (4) on the main surface of the substrate (1). In the transparent electrode layer forming step (S10), the transparent electrode layer forming step (step S11) for forming the transparent electrode layer (4) on the main surface, and the formed transparent electrode layer (4) includes a plurality of photoelectric layers. A transparent electrode layer etching step (step S12) for laser-etching the transparent electrode layer (4) so as to be divided corresponding to each of the conversion cells (7). In the transparent electrode layer etching step (S12), the transparent electrode layer (in the surrounding region (3) before the photoelectric conversion unit is removed across the power generation region that is the region from which power is extracted during power generation) The irradiation is performed such that the length of the line irradiated to 4) is 10 mm or less.

  As described above, when the transparent electrode layer (4) is subjected to laser etching, the length of the line irradiated with the laser to the surrounding region (3) is set to 10 mm or less, so that the laser mark in the surrounding region (3). The area where the occurrence of the occurrence of the problem may occur can be made smaller and can be separated from the edge of the substrate. As a result, it is possible to ensure a wide range of sound seals and adhesive surfaces when placing fillers such as EVA. Further, in the surrounding area forming step (S50), it is possible to prevent the occurrence of chipping on the substrate surface in the surrounding area (3) due to the laser mark. As a result, it is possible to prevent moisture from entering due to capillary action from the outside. If the length of the line irradiated with laser in the peripheral region (3) exceeds 10 mm, the region of the laser mark generated in the peripheral region (3) becomes large, and a sound seal is obtained because it approaches the substrate edge.・ It is difficult to secure a sufficient adhesive surface. Further, in the peripheral polishing step (S50), streaks and chips are generated as a result of laser marks, and moisture intrusion due to capillary action tends to occur from here.

In the above-described Patent Document 1, it is described that the solar cell region is surrounded by a region having a large adhesive force to the filler, but no countermeasure is taken against laser marks. On the other hand, according to the present invention, laser marks generated by laser etching can be minimized, and moisture intrusion from the edge of the substrate can be suppressed.
In addition, in the above-mentioned Patent Document 2, it is described that the optical semiconductor layer and the metal layer in the peripheral portion of the translucent substrate are removed mechanically or with a light beam. It is not described how to make the portion to be processed, and the influence of the laser mark is not taken into consideration. On the other hand, according to the present invention, laser marks generated by laser etching can be minimized, and moisture intrusion from the edge of the substrate can be suppressed.
In addition, Patent Document 3 described above describes that a groove extending from the back electrode layer, which is the surface of the power generation cell, to the substrate surface is provided so as not to reach the end of the substrate. However, as in the present invention, no countermeasure is taken against the laser mark, and the portion irradiated with the laser in the surrounding area is not devised. In the present invention, the length of the portion irradiated with the laser in the surrounding region is devised, and moisture intrusion due to the laser mark is suppressed.

  The method for manufacturing the photoelectric conversion device further includes an insulating groove for forming an insulating groove (8) by removing a part of the photoelectric conversion unit (2) by laser etching so that the translucent substrate is exposed by laser etching. When the etching process (step S40) is provided, when irradiating the photoelectric conversion unit (2) with a laser in the insulating groove etching process (step S40), the laser crosses the power generation region, which is a region from which power is extracted during power generation. Thus, the length of the portion where the irradiation line on the substrate (1) of the laser irradiated within the range of the peripheral region (3) before removing the photoelectric conversion unit (2) overlaps the peripheral region (3) Irradiation is preferably performed so that the thickness is 10 mm or less.

  In the surrounding region forming step (S50), it is preferable to remove the photoelectric conversion unit (2) so that the surrounding region (3) is formed with a width of 5 mm or more and 20 mm from the end of the substrate (1).

  Since the surrounding region (3) is formed with a width of 5 mm or more from the substrate end of the substrate (1), an insulation distance between the photoelectric conversion layer and the surrounding frame material (earth) state can be secured. Further, in order to reduce the peripheral region (3) while securing a space for preventing the melted EVA material from protruding from the edge of the substrate, a width of 20 mm or less is preferable.

  At least one of the transparent electrode layer etching step (S12) and the insulating groove etching step (S40) is based on the step of acquiring irradiation position information indicating the irradiation position of the laser on the substrate and the acquired irradiation position information. And a step of opening and closing a shutter disposed on the optical path of the laser.

  According to such a method, the laser irradiation position can be accurately controlled, and the region not subjected to laser etching can be controlled.

  In addition, in at least one of the transparent electrode layer etching step (S12) and the insulating groove etching step (S40), when irradiating the laser generated by pulse oscillation, the transparent electrode layer etching step (S12) and At least one of the insulating groove etching step (S40) includes a step of acquiring irradiation position information indicating a laser irradiation position on the substrate, and a step of controlling the laser oscillation frequency based on the acquired irradiation position information. It is preferable to provide.

  In this way, by controlling the laser oscillation frequency, the laser irradiation position can be accurately controlled, and the region where laser etching is hardly performed or the region where etching is hardly performed can be controlled.

  In addition, at least one of the transparent electrode layer etching step (S12) and the insulating groove etching step (S40) is performed by using a mask (15) that blocks the laser beam so that a region not to be etched is covered on the extension of the line to be etched. A laser is applied to at least one of a layer for performing the transparent electrode layer etching and a layer for performing the insulating groove etching on the substrate on which the mask (15) is disposed after the mask arranging step to be arranged and the mask arranging step. And irradiating.

  In this way, if laser etching is performed after a mask is arranged in a region that is not etched, the laser irradiation position and the region that is not laser-etched can be easily controlled.

  Moreover, it is preferable that at least one of the transparent electrode layer etching step (S12) and the insulating groove etching step (S40) includes a step of spraying gas onto the substrate to control the substrate temperature.

  In the portion irradiated with the laser, the laser energy is absorbed in the layer to be etched and heat is generated. It is considered that laser marks are generated on the substrate in the peripheral region (3) due to the generated heat. As described above, it is possible to prevent laser marks from being generated on the substrate in the surrounding region (3) due to heat generated by laser irradiation by spraying gas and controlling the substrate temperature.

  Further, in the surrounding region forming step (S50), the region in which the surrounding region (3) is to be formed is performed by at least two or more polishing steps, and the region of the region to be formed in the vicinity of the end surface of the substrate (1) There may be provided at least a first polishing step for polishing a part and a second polishing step for polishing the inner side on the power generation region side of the region polished in the first polishing step after the first polishing step. At this time, the polishing amount in the second polishing step is preferably smaller than the polishing amount in the first polishing step.

  In this way, by making the amount of polishing in the second polishing step smaller than that in the first polishing step, it is possible to prevent the occurrence of microcracks and chips on the substrate surface in the peripheral region (3).

  Here, in the first polishing step and the second polishing step, polishing may be performed by blast polishing. At this time, it is preferable that the relative feed speed of the blast irradiation position with respect to the substrate (1) in the second polishing process is faster than the relative feed speed of the blast irradiation position in the first polishing process.

  Thus, by making the relative feed speed of the blast irradiation position in the second polishing step faster than in the first polishing step, it is possible to reduce the amount of polishing in the peripheral region (3) in the second polishing step. It is possible to prevent the occurrence of micro cracks and chippings on the substrate exposed surface in the peripheral region (3).

  In the first polishing step and the second polishing step, when polishing is performed by blast polishing, the blast spray pressure on the substrate (1) in the peripheral region (3) in the second polishing step is the same as in the first polishing step. It is preferably lower than the blast spray pressure on the substrate (1) in the surrounding area (3).

  Thus, the amount of polishing in the second polishing step can also be reduced by lowering the blast spray pressure on the substrate (1) in the peripheral region (3) in the second polishing step than in the first polishing step. Therefore, generation | occurrence | production of the micro crack and chip on the board | substrate exposed surface of surrounding region (3) can be prevented.

A photoelectric conversion device as a reference example of the present invention includes a substrate (1), a photoelectric conversion unit (2) provided in a photoelectric conversion unit region on the main surface of the substrate (1), and a photoelectric conversion unit region. A peripheral region (3) which is provided on the peripheral edge of the substrate so as to surround the substrate and is an exposed region of the substrate. The photoelectric conversion unit (2) includes a transparent electrode layer (4) provided on the main surface, a photoelectric conversion layer (5) provided on the transparent electrode layer (4), and a photoelectric conversion layer (5). A back electrode layer (6) provided. The photoelectric conversion unit (2) is divided into a plurality of strip-shaped photoelectric conversion cells (7) in a power generation region that is a region from which electric power is extracted during power generation in the photoelectric conversion unit region. The transparent electrode layer (4) is divided by the transparent electrode layer dividing groove (9) so as to correspond to each of the plurality of photoelectric conversion cells (7). In the peripheral region (3) corresponding to the extended line of the transparent electrode layer dividing groove (7), the length of the laser mark formed on the surface of the substrate exceeds the end of the power generation region, which is a region where power is taken out during power generation. And it is 10 mm or less from the edge part of the said electric power generation area | region.

  In this photoelectric conversion device, an insulating groove (8) that is a groove from which the photoelectric conversion unit (2) has been removed is provided in the photoelectric conversion unit region. At this time, in the peripheral region (3) corresponding to the extended line of the insulating groove (8), the length of the laser mark formed on the surface of the substrate (1) is the end of the power generation region, which is a region where power is taken out during power generation. Over 10 parts and less than 10 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which keeps the surface state of the board | substrate in a surrounding area healthy and can prevent that a water | moisture content permeates from a board | substrate edge part by a capillary phenomenon is provided.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where a solar cell is used as a photoelectric conversion apparatus. Fig.4 (a) is a top view which shows the structure of the solar cell module of this embodiment.

  Similar to the conventional example (FIGS. 1A to 1C), the solar cell module includes a substrate 1 and a solar cell film 2. The substrate 1 is a translucent substrate such as glass, and the solar cell film 2 is provided in the solar cell film remaining region on the main surface of the substrate 1 (the surface opposite to the light receiving surface). At the peripheral portion of the main surface, the solar cell film 2 is removed to form a peripheral region 3 in order to secure a seal / adhesion surface with an adhesive sheet such as EVA that adheres the back sheet.

  The surrounding area 3 is preferably provided in an area of 5 mm or more from the end of the substrate 1 in order to ensure a sufficient adhesion surface with the backsheet. Further, from the viewpoint of sufficiently securing the area of the power generation region, the power generation region is preferably provided in a region of 20 mm or less from the end of the substrate 1. Since the surrounding region 3 is formed with a width of 5 mm or more from the substrate end of the substrate 1, an insulation distance between the photoelectric conversion layer and the surrounding frame material (ground) state can be secured. Furthermore, it is desirable that the back sheet covers a sufficiently wide portion of approximately 5 mm or more from the remaining area of the solar cell film, and considering that the melted EVA material for bonding the back sheet does not protrude from the edge of the substrate. A space of 10 to 15 mm or more is required in addition to the surrounding area 3. On the other hand, it is desirable to reduce the surrounding region 3 in order to ensure the area of the power generation region, and a width of substantially 20 mm or less is preferable.

  The solar cell film 2 is divided into a plurality of solar cells 7. Each of the plurality of solar cells 7 has a strip shape with the Y direction as the longitudinal direction. Insulating grooves 8 extending in the X direction are provided in the vicinity of both ends in the Y direction side of the solar cell film 2.

  FIG.4 (b) is a schematic sectional drawing which shows the XX cross section of Fig.4 (a). As shown in this figure, the solar cell film 2 includes a transparent electrode layer 4, a photoelectric conversion layer 5, and a back electrode layer 6. The transparent electrode layer 4 is formed on the main surface of the substrate 1. The photoelectric conversion layer 5 is formed on the transparent electrode layer 4. The back electrode layer 6 is formed on the photoelectric conversion layer 5. As described in the conventional example, the transparent electrode layer 4, the photoelectric conversion layer 5, and the back electrode layer 6 are formed in each solar cell 7 by the transparent electrode layer dividing groove 9, the groove 30, and the groove 31, respectively. It is divided to correspond. Moreover, the photoelectric conversion layer 5 is embedded in the transparent electrode layer dividing groove 9, and the back electrode layer 6 is embedded in the groove 30. A plurality of solar cells 7 are electrically connected in series with the adjacent cells 7 by the back electrode layer 6 buried in the groove 30.

  As shown in FIG. 4C, the insulating groove 8 is a groove from which the solar cell film 2 has been removed. As a result, even if moisture gradually enters from the edge of the substrate via the seal / bonding portion of the peripheral region 3, the inner portion of the insulating groove 8 is electrically connected to the outside, resulting in poor insulation. Is prevented. Of the solar cell film remaining region, the power is actually taken out during power generation is the power generation region inside the insulating groove 8.

  The solar cell module having the above-described configuration is manufactured as follows. FIG. 5 is a flowchart showing the overall flow of the method for manufacturing a solar cell module. When manufacturing the solar cell module, first, the transparent electrode layer 4 is formed on the substrate, and the separation groove is patterned at a predetermined position by laser etching (step S10). Subsequently, the photoelectric conversion layer 5 is formed and patterned (step S20). Subsequently, the back electrode layer 6 is formed and patterned (step S30). Subsequently, the insulating groove 8 is formed (step S40). Subsequently, the solar cell film 2 formed on the peripheral edge of the substrate 1 is removed by polishing to form the surrounding region 3 (step S50). Thereby, a solar cell module is manufactured. A back sheet, a terminal box, a frame, and the like are attached to the manufactured solar cell module in a later process to form a panel.

  In the present embodiment, the operations in the step of forming the transparent electrode layer 4 (S10) and the step of forming the insulating groove 8 (S40) are devised.

  In the step of forming the transparent electrode layer 4 (S10), first, the transparent electrode layer 4 is formed on the entire main surface of the substrate 1 (step 11). Next, the groove 9 is formed by laser etching so that the transparent electrode layer 4 is divided corresponding to each solar battery cell 7 (step S12).

  FIG. 6 is an explanatory view showing the state of the transparent electrode layer 4 during laser etching (step S12). In the figure, reference numeral 9L indicates a line irradiated with a laser (hereinafter referred to as a laser irradiation line 9L). Although the surrounding area 3 is illustrated in FIG. 6, in reality, the surrounding area 3 is not provided at this stage (stage where the transparent electrode layer 4 is divided), and the entire main surface of the substrate 1 is transparent. An electrode layer 4 is provided. Therefore, the surrounding area 3 drawn in this figure is an area where the surrounding area 3 is to be formed. Reference numeral 8L indicates a line (laser irradiation line 8L) that is to be irradiated with a laser when the insulating groove 8 is formed.

As shown in FIG. 6, the laser irradiation line 9 </ b> L extends in the Y direction in a region that becomes a power generation region. Here, the length L1 of the portion where the laser irradiation line 9L protrudes from the end of the solar cell film remaining region is 10 mm or less. The length L1 is preferably 7 mm or less. That is, the length that the laser irradiation line 9L protrudes into a region (surrounding region) that serves as an adhesive surface with the back sheet is 10 mm or less, preferably 7 mm or less.
Here, if the length of the line irradiated with laser in the peripheral region 3 exceeds 10 mm, the region of the laser mark generated here becomes larger than 50% with respect to the entire width of the peripheral region 3, and the substrate It is difficult to secure a sufficient seal / adhesion surface to approach the edge. On the other hand, if it exceeds 10 mm, streaks or chips are generated in the peripheral polishing step (S50) as a trigger of laser marks, and moisture intrusion due to capillary action newly generated here is likely to occur. When the test result is observed, in the peripheral polishing step (S50), 7 mm or less is more preferable in order to surely suppress the occurrence of streaks and chips caused by laser marks.
Although not shown in FIG. 6, after the laser irradiation line 9L for dividing the transparent electrode layer 4 is formed, a laser which is orthogonal to the line 9L and is parallel to the insulating groove planned line 8L in the vicinity of the insulating groove planned line 8L. A patterning line may be provided to electrically separate the patterned strip-shaped transparent electrode layer 4 at the substrate end. In this case, by measuring the interstage resistance of the patterned transparent electrode layer 4, it is possible to perform process monitoring for confirming that the patterning by the laser irradiation line 9 </ b> L is normally performed and electrically separated. .

  In the solar cell film remaining region, the power is actually extracted from the power generation region inside the insulating groove 8. The cells in the power generation region may be separated by the transparent electrode layer dividing groove 9. Therefore, the laser irradiation line 9L only needs to exceed the end of the power generation region, and does not necessarily extend to the end of the solar cell film remaining region. However, in practice, in order to reliably divide the transparent electrode layer in the power generation region in consideration of the laser irradiation position error accompanying the temperature change of the substrate 1 and the positioning accuracy, the end of the solar cell film remaining region is reached. In many cases, management is performed by performing laser irradiation.

  In the step of forming the insulating groove 8 (S40), the laser is irradiated along the laser irradiation line 8L in FIG. Here, like the laser irradiation line 9L, the length (L2) of the portion where the laser irradiation line 8L protrudes from the end of the solar cell film remaining region (planned) is 0 mm or more and 10 mm or less, preferably 7 mm or less. . That is, the length that the laser irradiation line 8L protrudes into a region that becomes a sealing / bonding surface with EVA or the like that joins the back sheet is 0 mm or more and 10 mm or less, preferably 7 mm or less.

  As described above, in steps S11 and S40, by irradiating the laser along the laser irradiation lines 9L and 8L, respectively, there is a possibility that the laser mark as shown in FIG. A certain part can be made sufficiently small. As a result, the surrounding region 3 and the adhesive sheet such as EVA are soundly formed without creating a continuous minute gap in which moisture enters from outside by capillarity or the like between the surrounding region 3 and the adhesive sheet such as EVA that joins the back sheet. It can adhere | attach and can prevent that a water | moisture content permeates into an electric power generation area | region from an edge part.

Further, when the solar cell film 2 is polished to form the peripheral region 3 (S50), since the generation of laser marks in the peripheral region 3 is suppressed, the laser marks are used as a trigger for cracks and microcracks in the substrate. Is not generated, and the minute gap for generating the capillary phenomenon with the outside is not increased, so that moisture can be prevented from entering the power generation region from the end.
That is, if the length of the line irradiated with laser in the peripheral region 3 exceeds 10 mm, the region of the laser mark generated here becomes larger than 50% with respect to the entire width of the peripheral region 3, and the substrate edge It becomes difficult to secure a sufficient seal and adhesive surface to approach On the other hand, if it exceeds 10 mm, streaks or chips are generated in the peripheral polishing step (S50) as a trigger of laser marks, and moisture intrusion due to capillary action newly generated here is likely to occur. When the test result is observed, in the peripheral polishing step (S50), 7 mm or less is more preferable in order to surely suppress the occurrence of streaks and chips caused by laser marks. Needless to say, the length of the line irradiated with laser in the surrounding region 3 needs to be 0 mm or more from the configuration of the power generation region.

  When the solar cell module manufactured as described above was observed with a microscope in the vicinity of the substrate end of the peripheral region 3 after the peripheral region formation (S50), no laser trace was found. In addition, it was confirmed that a defective polished surface portion such as a substrate chip or a microcrack could not be confirmed, and a sound surface state was obtained.

(Example)
Next, the present embodiment will be described more specifically with reference to examples.

  First, the structure of the solar cell panel manufactured by the present example will be described. FIG. 7 is a schematic view showing the configuration of the solar cell module manufactured according to this example. The solar cell module is a silicon-based solar cell, and includes a substrate 1, a transparent electrode layer 4, a solar cell photoelectric conversion layer 5, and a back electrode layer 6. The photoelectric conversion layer 5 is a silicon-based thin film solar cell such as an amorphous silicon solar cell. A tandem solar cell including the second cell layer 52 may be used as the first cell layer 51. Here, the silicon-based is a generic name including silicon (Si), silicon carbide (SiC), and silicon germanium (SiGe).

  Next, an embodiment of a method for manufacturing a solar cell panel of the present invention will be described. Here, a multi-junction type (tandem type) solar cell using a layer in which an amorphous silicon solar cell and a crystalline silicon solar cell are stacked as a solar cell photoelectric conversion layer 5 on a glass substrate as the substrate 1 is taken as an example. Will be described. 8A to 8D are schematic views showing an embodiment of a method for manufacturing a solar cell panel according to the present invention.

(1) FIG. 8A (a):
A soda float glass substrate (1.4 m × 1.1 m × plate thickness: 4 mm) is used as the substrate 1. It is desirable that the end face of the substrate is corner chamfered or rounded to prevent breakage.
(2) FIG. 8A (b):
As the transparent electrode layer 4, a transparent electrode film mainly composed of a tin oxide film (SnO ₂ ) is formed into a film at about 500 ° C. to 800 nm at 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 electrode layer 4, in addition to the transparent electrode film, an alkali barrier film (not shown) may be formed between the substrate 1 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 at 50 nm to 150 nm.
(3) FIG. 8A (c):
Thereafter, the substrate 1 is placed on an XY table, and the first harmonic (1064 nm) of the YAG laser is incident from the film surface side of the transparent electrode film as indicated by the arrow in the figure. The laser power is adjusted so as to be suitable for the processing speed, and the transparent electrode layer is divided into transparent electrode layers by moving the transparent electrode film relative to the direction perpendicular to the series connection direction of the solar cells 7 and the laser beam. Laser etching is performed in a strip shape having a width of about 6 mm to 15 mm so as to form the groove 9. At this time, as already described with reference to FIG. 6, laser etching is performed so that the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region.
(4) FIG. 8A (d):
Using a plasma CVD apparatus, a p layer film / i layer film / n layer film (first cell layer 51) made of an amorphous silicon thin film as the photoelectric conversion layer 5 at a reduced pressure atmosphere: 30 to 1000 Pa and a substrate temperature: about 200 ° C. Sequentially form a film. The photoelectric conversion layer 5 is formed on the transparent electrode layer 4 using SiH ₄ gas and H ₂ gas as main raw materials. The p-layer, i-layer, and n-layer are stacked in this order from the sunlight incident side. In the present embodiment, the photoelectric conversion layer 5 is a p-layer: B-doped amorphous SiC and mainly a film thickness of 10 nm to 30 nm, an i-layer: amorphous Si and a film thickness of 200-350 nm, and an n-layer: p-doped microcrystalline Si. The film thickness is 30 nm 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.

Next, a microcrystalline silicon thin film as the second cell 52 is formed on the first cell layer 51 by a plasma CVD apparatus at a reduced pressure atmosphere: 3000 Pa or less, a substrate temperature: about 200 ° C., and a plasma generation frequency: 40 MHz to 100 MHz. A microcrystalline p-layer film / a microcrystalline i-layer film / a microcrystalline n-layer film are sequentially formed.
In this embodiment, the second cell 52 is mainly composed of a microcrystalline p layer: B-doped microcrystalline SiC and a film thickness of 10 nm to 50 nm, and a microcrystalline i layer: mainly microcrystalline Si, and a film thickness of 1.2 μm to 3.0 μm. Microcrystalline n layer: Mainly composed of p-doped microcrystalline Si, with a film thickness of 20 nm to 50 nm.

  In forming a microcrystalline silicon thin film, particularly a microcrystalline i-layer film, by plasma CVD, the distance d between the plasma discharge electrode and the surface of the substrate 1 is preferably 3 mm to 10 mm. If it is smaller than 3 mm, it is difficult to keep the distance d constant from the accuracy of each component device in the film forming chamber corresponding to the large substrate, and there is a possibility that the discharge becomes unstable because it is too close. When it is larger than 10 mm, it is difficult to obtain a sufficient film forming speed (1 nm / s or more), and the uniformity of the plasma is lowered and the film quality is lowered by ion bombardment.

  A GZO (Ga-doped ZnO) film serving as a semi-reflective film is used to improve the contact between the first cell layer 51 and the second cell layer 52 and to obtain current matching, and the film thickness is 20 nm. The film may be formed by ˜100 nm using a sputtering apparatus. Further, the intermediate contact layer 53 may not be provided.

(5) FIG. 8A (e)
The 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 5 as indicated by an 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 the lateral side of about 100 to 150 μm of the laser etching line (transparent electrode layer dividing groove 9) of the transparent electrode layer 4 is formed on the groove 30. Laser etching to form It may be incident from the substrate 1 side, and in this case, the second cell layer 52 can be etched using the high gas vapor pressure generated by the energy absorbed in the amorphous silicon thin film of the first cell layer 51. Furthermore, laser etching can be performed stably. The position of the laser etching line is selected in consideration of positioning intersection so as not to intersect with the etching line in the previous process.

(6) FIG. 8B (a)
As the back electrode layer 6, an Ag film / Ti film is sequentially formed by a sputtering apparatus at about 150 ° C. in a reduced pressure atmosphere. In this embodiment, the back electrode layer 6 is formed by stacking an Ag film: 200 to 500 nm and a Ti film having a high anticorrosive effect: 10 to 20 nm in this order as a protective film. For the purpose of reducing contact resistance between the n-layer and the back electrode layer 6 and improving light reflection, a GZO (Ga-doped ZnO) film is formed between the photoelectric conversion layer 5 and the back electrode layer 6 in a film thickness: 50 to 100 nm, a sputtering apparatus. May be provided by forming a film.
(7) FIG. 8B (b)
The 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 substrate 1 side as shown by the arrow in the figure. Laser light is absorbed by the photoelectric conversion layer 5, and the back electrode layer 6 is exploded and removed using the high gas vapor pressure 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 the lateral side of about 250 to 400 μm of the laser etching line (transparent electrode layer dividing groove 9) of the transparent electrode layer 4 is formed in the groove 31. Laser etching to form
(8) FIG. 8B (c) and FIG. 8C (a)
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 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 substrate 1 side. Laser light is absorbed by the transparent electrode layer 4 and the photoelectric conversion layer 5, and the back electrode layer 6 explodes using the high gas vapor pressure generated at this time, and the back electrode layer 6 / photoelectric conversion layer 5 / transparent electrode layer 4 is removed. Pulse oscillation: 1 to 10 kHz, the laser power is adjusted so as to be suitable for the processing speed, and the position of 5 to 20 mm from the end of the substrate 1 is placed in the X-direction insulating groove 8 as shown in FIG. Laser etching to form At this time, the Y-direction insulating groove does not need to be provided because the film surface polishing removal process in the peripheral region of the substrate 1 is performed in a later step. FIG. 8B (C) shows a cross section in the X direction and a cross section in the Y direction for convenience in order to show the laser irradiation position.
At this time, as already described with reference to FIG. 6, laser etching is performed so that the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region.
In addition, although the laser beam in the above process is made into a YAG laser, there exists what can use a YVO4 laser, a fiber laser, etc. similarly.

(9) FIG. 8C (a: view from the solar cell film side, b: view from the substrate side of the light receiving surface)
In order to ensure a healthy adhesion / seal surface with the back sheet 33 via EVA or the like in a later process, the laminated film around the substrate 1 (peripheral region 3) has a step and is easy to peel off. Remove. When removing the film over the entire circumference of the substrate 1 at 5 to 20 mm from the end of the substrate 1, the X direction is closer to the substrate end than the insulating groove 8 provided in the above-described step of FIG. The back electrode layer 6 / photoelectric conversion layer 5 / transparent electrode layer 4 are removed by using grinding stone polishing, blast polishing or the like on the substrate end side with respect to the groove 9 near the side portion. At this time, in order to perform polishing so that there is no residual film, a slight amount of the exposed surface of the substrate 1 is also polished. Polishing debris and abrasive grains were removed by cleaning the substrate 1.
(10) FIG. 8D (a)
At the terminal box mounting portion, an opening through window is provided in the back sheet 33 and the current collector plate is taken out. A plurality of layers of insulating materials are installed in the opening through window portion to suppress intrusion of moisture and the like from the outside.
It processes so that it can collect electric power from the photovoltaic cell 7 of the one end lined up in series and the photovoltaic cell 7 of the other end part using copper foil, and can take out electric power from the terminal box part of a photovoltaic panel back side. In order to prevent a short circuit with each part, the copper foil arranges an insulating sheet wider than the copper foil width.
After the current collecting copper foil or the like is disposed at a predetermined position, an adhesive filler sheet made of EVA (ethylene vinyl acetate copolymer) or the like is disposed so as to cover the entire solar cell module and not protrude from the substrate 1.
A back sheet 33 having a high waterproof effect is installed on the EVA. In this embodiment, the back sheet 33 has a three-layer structure of PET 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 33 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.

(11) FIG. 8D (b)
The terminal box 32 is attached to the back side of the solar cell module with an adhesive. The copper foil and the output cable of the terminal box 32 are connected with solder or the like, and the inside of the terminal box is filled with a sealing agent (potting agent) and sealed. This completes the solar cell panel.

(12) FIG. 8D (c)
A power generation inspection and a predetermined performance test are performed on the solar cell panel formed through the steps up to FIG. The power generation inspection is performed using a solar simulator of AM1.5 and solar radiation standard sunlight (1000 W / m ² ).
(13) FIG. 8D (d)
Before and after the power generation inspection (FIG. 8D (c)), a predetermined performance inspection is performed including an appearance inspection.

(I) Insulation inspection:
A DC: 1000V load is applied between the output terminal of the laminated solar cell panel and the conductive portion such as the end face of the substrate and the back sheet, and it is confirmed that the resistance value ≧ 100 MΩ.
(Ii) Dielectric strength test DC: 3800V (or 2200V) was applied for 1 minute between the output terminal of the laminated solar cell panel and the conductive part such as the substrate end face or back sheet to confirm that there was no dielectric breakdown. To do.

  By the said manufacturing method, the solar cell panel used as the product using this invention was manufactured, and it confirmed that the characteristic was not different from the thing by the conventional process.

  In addition, a high-temperature and high-humidity test (JISC8938) was performed on the solar cell panel manufactured in this example. That is, after performing light exposure for 20 hours and stabilizing the performance in advance, the performance (open circuit voltage Voc, short circuit current Isc, and maximum output Pmax) and appearance after 1000 hours at a temperature of 85 ° C. and a humidity of 85% It was confirmed that there was no change. Further, the performance after 1500 hours was measured as an evaluation time for the unique long-term durability (open circuit voltage Voc, short-circuit current Isc, maximum output Pmax, and appearance observation) by extending beyond the evaluation time of JISC8938.

  As a comparative example, a solar cell panel was prepared in which laser etching was performed up to the edge of the substrate during laser etching of the transparent electrode layer and laser etching of the insulating groove. And the high temperature / humidity test was done like the solar cell panel manufactured by the present Example.

  The result of the high temperature and high humidity test is shown in FIG. In addition, about each of an Example and a comparative example, the measurement for 3 panels was performed. Regarding Voc, Isc, and Pmax, the average value after 1000 hours of the comparative example is shown as 100%.

  As a result, in the comparative example, after 1500 hours, all of Voc, Isc and Pmax were lower than 100%. Further, after 1500 hours, in one of the three panels, although it was very small, a trace that appeared to be a flooded channel from the edge of the substrate was observed.

  On the other hand, in Examples, the values of Voc, Isc, and Pmax were almost 100% after 1000 hours and 1500 hours, and it was confirmed that there was almost no change in performance over time. Also, no change was observed in appearance. From this, it was confirmed that the solar cell panel of the example had less performance change and further improved the reliability as compared with the comparative example.

In the above embodiment, the case where a tandem solar cell having an amorphous silicon photoelectric conversion layer as a top cell and a crystalline (microcrystalline) silicon photoelectric conversion layer as a bottom cell is used as the solar cell has been described. However, the present invention is not limited to this example.
For example, a single-layer amorphous silicon solar cell having only an amorphous silicon photoelectric conversion layer as a photoelectric conversion layer, or a multi-junction solar cell provided with one or more other photoelectric conversion layers in addition to a top cell and a bottom cell The present invention can be similarly applied to other types of thin film solar cells.

(Second Embodiment)
Next, the second embodiment will be described. The present embodiment is further devised with respect to the first embodiment in the step of laser etching the transparent electrode layer (S12) and the step of forming an insulating groove (S40). Since other points can be the same as those in the first embodiment, a detailed description thereof will be omitted.

  FIG. 10 is an explanatory diagram for explaining the state of the step (S12) of laser-etching the transparent electrode layer 4. The substrate 1 on which the transparent electrode layer 4 is formed on the entire main surface is disposed on the XY table 14. A laser beam 12 generated by an oscillator 10 is irradiated on the substrate 1. In the portion irradiated with the laser beam 12, the transparent electrode layer 4 is etched. The XY table 14 is movable in the X direction and the Y direction by the driving device 13. At the time of laser irradiation, the driving device 13 moves the XY table 14 in the Y direction, and moves the substrate 1 by a predetermined pitch in the X direction when the irradiation position of the laser beam 12 passes through the substrate 1. And a relative movement of the irradiation position of the laser beam 12 are performed. Thereby, the irradiation position of the laser on the board | substrate 1 changes, and the transparent electrode layer division | segmentation groove | channel 9 is formed along a Y direction.

A shutter 11 is provided on the optical path of the laser beam 12. Opening and closing of the shutter 11 is controlled by a shutter control device 17. The shutter control device 17 is exemplified by a computer. The shutter control device 17 acquires information on the substrate position (irradiation position information) from the drive device 13 by using an encoder or the like with the drive amount of the XY table 14 attached to the drive shaft, and controls the shutter 11 based on the acquired information. Open and close. At that time, the shutter control device 17 opens and closes the shutter so that the line irradiated with the laser exceeds the power generation region and becomes 10 mm or less in the surrounding region. More preferably, the shutter 11 is opened and closed so that the length of the line irradiated with the laser in the region to be the surrounding region 3 is 7 mm or less.
Here, the opening / closing of the shutter has been described by taking ON / OFF of the laser beam 12 on the optical path as an example. However, even if the laser beam 12 on the optical path is not turned off by a shield, the angle of the optical mirror can be changed, This is a general term for changes in the conditions of the laser beam 12 that are performed so that the film to be processed is not substantially etched, such as changing the focal position of the laser beam 12 by changing the position of the optical lens.

  Also in the step of forming the insulating groove (S40), similarly to S12, the shutter control device 17 controls the opening and closing of the shutter 11, whereby the laser irradiation position is controlled. During laser irradiation, the driving device 13 moves the XY table 14 in the X direction. As in S12, the shutter control device 17 opens and closes the shutter so that the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region. More preferably, the shutter 11 is opened and closed so that the length of the line irradiated with the laser in the region to be the surrounding region 3 is 7 mm or less.

  As in this embodiment, by controlling the opening and closing of the shutter 11 based on the driving amount of the XY table, the laser irradiation position can be accurately controlled. Therefore, it is possible to adhere to the surrounding area 3 and an adhesive sheet such as EVA that joins the back sheet without making a continuous minute gap that causes capillary action from the outside, and moisture from the edge of the substrate. Intrusion into the power generation area can be prevented.

(Third embodiment)
Subsequently, a third embodiment will be described. In the present embodiment, the step of laser etching the transparent electrode layer (S12) and the step of forming an insulating groove (S40) are further devised with respect to the above-described embodiments. Since the other points can be the same as those of the above-described embodiment, detailed description thereof is omitted.

  FIG. 11 is an explanatory diagram for explaining the state of the step of laser etching the transparent electrode layer 4 (S12). The substrate 1 on which the transparent electrode layer 4 is formed on the entire main surface is disposed on the XY table 14. A laser beam 12 generated by an oscillator 10 is irradiated on the substrate 1 in a pulse shape. In the portion irradiated with the laser beam 12, the transparent electrode layer 4 is etched. The XY table 14 is movable in the X direction and the Y direction by the driving device 13. At the time of laser irradiation, the driving device 13 moves the XY table 14 in the Y direction. By appropriately selecting the moving speed of the substrate 1 and the pulse generation frequency of the laser beam 12, the transparent electrode layer 4 is processed into dots by pulsed irradiation, and some of these dots overlap. Thereby, the irradiation position of the laser on the board | substrate 1 changes, and the transparent electrode layer division | segmentation groove | channel 9 is formed along a Y direction.

  The oscillator 10 generates a laser beam by pulse oscillation. An oscillation control device 18 is connected to the oscillator 10. The oscillation control device 18 is exemplified by a computer. The oscillation control device 18 acquires information indicating the amount of movement of the XY table 14 from the drive device 13 and controls the laser oscillation frequency of the oscillator 10. At that time, a relatively high frequency (several kHz to several kHz) is applied to a position (laser irradiation line 9L in the first embodiment) to be irradiated with laser so that the transparent electrode layer 4 is continuously removed. The laser is oscillated at 10 kHz. On the other hand, on the extended line of the laser irradiation line 9L, the laser oscillation frequency is changed to a sufficiently low frequency so that the transparent electrode layer 4 is not continuously removed. By changing the laser oscillation frequency to a sufficiently low frequency, continuous laser irradiation is not performed, and the area that is not to be etched is not irradiated with laser, or even when irradiated, the distance between dots is wide and continuous. The separation groove is not formed, and the heat influence on the substrate 1 can be reduced.

  As described above, the oscillation control device 18 controls the oscillation frequency of the laser so that the line irradiated with the laser substantially exceeds the power generation region and is 10 mm or less in the surrounding region. . More preferably, the length of the line irradiated with the laser in the region to be the surrounding region 3 is set to 7 mm or less.

  Also in the step of forming the insulating groove (S40), as in S12, the oscillation control device 18 controls the laser oscillation conditions of the oscillator 10, whereby the substantial laser irradiation position is controlled. Similarly to S12, the oscillation control device 18 controls the oscillation conditions so that the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region. More preferably, the oscillation conditions are controlled so that the length of the line irradiated with the laser in the region to be the surrounding region 3 is 7 mm or less.

  As in this embodiment, by controlling the laser oscillation frequency based on the drive amount of the XY table, it is possible to accurately control the laser irradiation position and secure a non-etched area. Become. Therefore, it is possible to adhere to the surrounding area 3 and the adhesive sheet such as EVA that joins the back sheet without making a continuous minute gap that causes capillary action with the outside, and moisture from the edge of the substrate. Intrusion into the power generation area can be prevented.

(Fourth embodiment)
Subsequently, a fourth embodiment will be described. In the present embodiment, the step of laser etching the transparent electrode layer (S12) and the step of forming an insulating groove (S40) are further devised with respect to the above-described embodiments. Since the other points can be the same as those of the above-described embodiment, detailed description thereof is omitted.

  FIG. 12 is an explanatory diagram for explaining the state of the step (S12) of laser-etching the transparent electrode layer 4. The substrate 1 on which the transparent electrode layer 4 is formed on the entire main surface is disposed on the XY table 14.

  In the present embodiment, a mask 15 is further disposed on the substrate 1. As the mask 15, a mask that absorbs less light and is less likely to be deformed even when irradiated with laser light is preferable, and prevents the laser light from reaching the etching target film of the substrate 1. An example of such a mask is a metal mask. For example, an Al-based plate having a thickness of 1 to 3 mm or a SUS plate having a high reflectance by surface polishing can be preferably used. The XY table 14 may be provided with a mechanism such that the mask 15 is automatically positioned near the substrate surface when the substrate 1 is placed on the XY table 14.

  The mask 15 is disposed so as to cover a region that is not to be etched (on the extended line of the laser irradiation line 9L). A laser beam 12 is applied to the substrate 1 on which the mask 15 is arranged. In the power generation region (planned), the transparent electrode layer 4 is etched by laser irradiation, and the transparent electrode layer dividing groove 9 is formed. On the other hand, in the region not to be etched, the substrate 1 is protected by the mask 15 and etching is not performed. As described above, by arranging the mask 15, the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region. More preferably, the length of the line irradiated with the laser in the region to be the surrounding region 3 is set to 7 mm or less.

  Also in the step of forming the insulating groove (S40), the region to be non-etched is protected by the mask 15 as in S12. Then, the line irradiated with the laser exceeds the power generation region and is 10 mm or less in the surrounding region. More preferably, the length of the line irradiated with the laser in the region to be the surrounding region 3 is set to 7 mm or less.

  Also by arranging the mask 15 as in the present embodiment, the line irradiated with the laser can exceed the power generation region and be 10 mm or less (more preferably 7 mm or less) in the surrounding region. At this time, there is no need for an apparatus for controlling the laser irradiation by monitoring the laser irradiation position on the substrate. The position of laser etching can be reliably controlled at low cost by a simple operation of arranging the mask 15. Therefore, it is possible to adhere to the surrounding area 3 and the adhesive sheet such as EVA that joins the back sheet without making a continuous minute gap that causes capillary action with the outside, and moisture from the edge of the substrate. Intrusion into the power generation area can be prevented.

(Fifth embodiment)
Subsequently, a fifth embodiment will be described. In the present embodiment, the step of laser etching the transparent electrode layer (S12) and the step of forming an insulating groove (S40) are further devised with respect to the above-described embodiments. Since the other points can be the same as those of the above-described embodiment, detailed description thereof is omitted.

  FIG. 13 is an explanatory diagram for explaining the state of the step (S12) of laser-etching the transparent electrode layer 4. The substrate 1 on which the transparent electrode layer 4 is formed on the entire main surface is disposed on the XY table 14. Similar to the fourth embodiment, the mask 15 is disposed so as to protect the non-etched region. The transparent electrode layer 4 is irradiated with a laser beam 12 generated by an oscillator (not shown in FIG. 12).

  In the present embodiment, cooling air is blown onto the substrate 1 by the cooling nozzle 16 during laser irradiation. Thus, by blowing air onto the substrate 1, the substrate 1 is cooled, and the surface of the substrate 1 is deformed by the heat generated during laser irradiation, or chipping based on minute grooves on the substrate surface. Generation of streaks can be prevented. Further, thermal expansion of the substrate 1 can be prevented, and laser etching can be performed with high accuracy.

The cooling air is preferably blown to the laser irradiation surface side of the substrate 1. The temperature of the blown air is preferably close to the substrate temperature from the viewpoint of ensuring the precision of microfabrication. In order to deal with the substrate after the film forming process and the cleaning process, the temperature is about 30 ° C to 35 ° C. The preheated air is preferred. Further, by blowing cooling air, the evaporated transparent electrode layer (SnO ₂ or the like) is reattached as a residue, and short-circuiting between adjacent ones of the patterned transparent electrode layers 4 can be suppressed. Therefore, it is possible to adhere to the surrounding area 3 and the adhesive sheet such as EVA that joins the back sheet without making a continuous minute gap that causes capillary action with the outside, and moisture from the edge of the substrate. Intrusion into the power generation area can be prevented.

(Sixth embodiment)
Subsequently, a sixth embodiment will be described. In the present embodiment, the step (S50) of polishing the surrounding region is further devised with respect to the above-described embodiments. Since the other points can be the same as those of the above-described embodiment, detailed description thereof is omitted.

  FIG. 14 is a block diagram schematically showing a configuration of a blast polishing apparatus used when polishing the surrounding region 3. The blast polishing apparatus 20 includes a compressor 21, an injection pressure adjusting valve 22, a feeder 23, a pressure tank 24, a cyclone 25, a dust collector 26, a nozzle 27, a blast nozzle driving device 28, and a recovery hopper 29. At the time of polishing, the abrasive material is sprayed from the feeder 23 to the substrate 1 through the nozzle 27, and the substrate 1 masks the unnecessary portion (the solar cell film remaining region), so that the solar cell film 2 in the peripheral region 3 is masked. Is removed. At this time, polishing is performed until the solar cell film 2 is removed without leaving, so that the exposed surface of the substrate 1 is slightly shaved with an abrasive. The position of the nozzle 27 can be moved by a blast nozzle driving device 28. As a result, the abrasive can be sprayed to a desired position on the substrate 1. The injected abrasive is collected by the collection hopper 29 and sent to the cyclone 25. In the cyclone 25, the abrasive is separated from defective abrasive that becomes dusty and fine and cannot be reused. Dust and defective abrasive are sent to the dust collector, and the abrasive is sent to the pressure tank 24. The abrasive sent to the pressure tank is sent again to the feeder 23 and sprayed onto the substrate 1 through the nozzle 27. A compressor 21 is connected to the pressure tank 24 and the feeder 23 via an injection pressure adjustment valve 22. By adjusting the injection pressure adjusting valve 22, the injection pressure of the abrasive is adjusted.

  FIG. 15A is an explanatory diagram for explaining the spray position of the abrasive on the substrate 1. In the present embodiment, first, the surrounding region 3 is formed by a plurality of polishing processes at least twice. First, the outer side which is the substrate end side in the peripheral region 3 (planned) is polished (first polishing step). Next, the inner side which is the power generation region side of the region polished in the first polishing step is polished (second polishing step). In the second polishing step, a region partially lapped (for example, 5 mm) with the polishing region in the first polishing step is polished. When an unpolished region exists in the surrounding region 3 after the second polishing step, the inner side on the power generation region side of the main polishing region in the second polishing step in the surrounding region 3 (planned) is further added. 3 Polishing is performed as a polishing process. Further, when there is an unpolished region in the surrounding region 3, the number of polishings may be continued to the third and fourth polishing steps. Thus, the entire surrounding region 3 is polished. In FIG. 15A, the first and second polishing steps in the X direction are performed after the first and second polishing steps in the Y direction are completed, but continuous polishing from the Y direction to the X direction is performed. You may carry out like this.

  Here, the relative feed rate in the second polishing step is increased with respect to the relative feed rate of the blast nozzle 27 relative to the substrate 1 in the first polishing step (relative feed rate at the blast injection position, eg, 20 m / min) (example). : 30 m / min). FIG. 16A is a graph showing the relationship between the abrasive injection amount per unit time, the grinding depth of the substrate 1, and the relative feed speed of the blast nozzle. In the figure, the nozzle feed speed is a relative value. That is, when the nozzle relative feed rate = 18 and the nozzle relative feed rate = 30, the nozzle relative feed rate = 30 is faster. As shown in FIG. 16A, when the relative feed speed of the nozzle is fast (nozzle feed speed = 30), the grinding depth on the surface of the substrate 1 becomes small. Further, if the abrasive injection amount per unit time is reduced, the grinding depth is reduced.

  When the surrounding region 3 is polished, the polishing is performed so that the solar cell film 2 is completely removed. At this time, not only the solar cell film 2 but also the exposed surface of the underlying substrate 1 is polished. When the amount of polishing of the exposed surface of the substrate 1 increases, microcracks and chips are easily generated on the exposed surface of the substrate 1 exposed in the peripheral region 3 of the substrate 1. In particular, chipping lines are likely to occur due to a minute laser processing groove remaining on the surface of the substrate 1 exposed in the surrounding area 3. As in the present embodiment, by increasing the relative feed rate in the second polishing step, the amount of polishing of the substrate 1 exposed surface, which is the base, can be reduced, and the generation of chipping lines, microcracks, and chips on the substrate exposed surface can be reduced. Can be prevented. As shown in FIG. 15B, at the end of the first polishing step, the region where the second polishing step is scheduled to be performed is also slightly polished. Therefore, the first polishing step can be performed by reducing the polishing amount in the second polishing step. It is possible to make the polishing region implemented by the polishing and the second polishing substantially uniform throughout the polishing area.

  In addition, since the amount of polishing is reduced, variation in the amount of polishing is reduced, and quality monitoring becomes easy. Therefore, it is possible to adhere to the surrounding area 3 and the adhesive sheet such as EVA that joins the back sheet without forming a continuous minute gap that becomes a capillary phenomenon with the outside, and to adhere moisture from the edge of the substrate. Can be prevented from entering the power generation area.

(Seventh embodiment)
Subsequently, a seventh embodiment will be described. In the sixth embodiment, the relative feed speed of the nozzle 27 is increased in the second polishing step, whereas in the present embodiment, the spray pressure of the abrasive on the surface of the substrate 1 is decreased in the second polishing step. Since other points can be the same as those in the sixth embodiment, detailed description thereof is omitted.

  FIG. 16B is a graph showing the relationship between the abrasive spray pressure (blast spray pressure), the abrasive spray amount, and the grinding depth of the substrate 1 on the surface of the substrate 1. In the figure, the injection amount is shown as a relative value. That is, the injection amount = 4.2 indicates that the abrasive injection amount per unit time is larger than the injection amount = 3.1. As shown in FIG. 16B, the grinding depth decreases as the spray pressure of the abrasive on the surface of the substrate 1 decreases. Further, when the abrasive spray amount is reduced, the grinding depth is reduced. Accordingly, as shown in FIG. 15B, the second polishing step is performed by polishing the abrasive pressure on the surface of the substrate 1 in the second polishing step in a region where the abrasive pressure is lower than that in the first polishing step. The amount of polishing of the substrate 1 in the process is reduced. As a result, as in the sixth embodiment, it is possible to prevent generation of microcracks and chipping on the exposed surface of the substrate and minimize the amount of polishing of the substrate 1. Usually, since the spray pressure of the abrasive on the surface of the substrate 1 tends to decrease from the vicinity of the center of the nozzle 27 toward the periphery, it is possible to appropriately select a polishing region overlapping in the first polishing step and the second polishing step. In the second polishing step, there is a region to be polished overlapping with the first polishing step. For this reason, the spray pressure of the abrasive material on the surface of the substrate 1 in the second polishing step in the region of 50% or more is substantially equal to the area near the center of the nozzle 27 where the first polishing step is performed on the surface of the substrate 1. Therefore, it can be made smaller than the spraying pressure of the abrasive on the surface of the substrate 1 in the first polishing step. That is, as shown in FIG. 15C, at the end of the first polishing process, since the region where the second polishing process is scheduled to be performed is also slightly polished, the position of the second polishing process nozzle 27 is appropriately selected. By reducing the polishing amount in the second polishing step, it becomes possible to make the polishing region implemented by the first polishing and the second polishing substantially uniform throughout the polishing area. In addition, since the amount of polishing is reduced, variation in the amount of polishing is reduced, and quality monitoring becomes easy. Therefore, it is possible to adhere to the surrounding area 3 and the adhesive sheet such as EVA that joins the back sheet without making a continuous minute gap that causes capillary action with the outside, and moisture from the edge of the substrate. Intrusion into the power generation area can be prevented.

  The abrasive injection pressure can be adjusted by an injection pressure adjusting valve 22 (see FIG. 13). The injection pressure adjusting valve 22 can be configured by providing a bumper or the like in the middle of the piping, and can be easily adjusted.

  Further, as shown in FIGS. 16A and 16B, when the abrasive spray amount per unit time is reduced, the grinding depth is reduced. Therefore, the polishing amount of the substrate 1 can be reduced by making the abrasive injection amount in the second polishing step smaller than the abrasive injection amount in the first polishing step by providing a bypass passage for the abrasive injection. it can. Even in this case, it is possible to prevent the generation of microcracks and chips on the substrate surface. In addition, since the amount of polishing is reduced, variation in the amount of polishing is reduced, and quality monitoring becomes easy.

  The first to seventh embodiments have been described above. Note that these embodiments are not independent from each other, and can be used in combination without any contradiction.

It is a figure which shows the structure of a solar cell module. It is a graph which shows the surface roughness of a surrounding area. It is explanatory drawing for demonstrating the laser trace of a surrounding area. It is a figure which shows the structure of the solar cell module of 1st Embodiment. It is a flowchart which shows the manufacturing method of the solar cell module of 1st Embodiment. It is an enlarged view which expands and shows a part of FIG. It is sectional drawing which shows the structure of a solar cell panel. It is process sectional drawing which shows the manufacturing method of a solar cell panel. It is process sectional drawing which shows the manufacturing method of a solar cell panel. It is process sectional drawing which shows the manufacturing method of a solar cell panel. It is process sectional drawing which shows the manufacturing method of a solar cell panel. It is a figure which shows the result of a high temperature, high humidity test. It is explanatory drawing which shows the mode of the transparent electrode layer laser etching process in 2nd Embodiment. It is explanatory drawing which shows the mode of the transparent electrode layer laser etching process in 3rd Embodiment. It is explanatory drawing which shows the mode of the transparent electrode layer laser etching process in 4th Embodiment. It is explanatory drawing which shows the mode of the transparent electrode layer laser etching process in 5th Embodiment. It is a schematic block diagram which shows the structure of a blast grinding | polishing apparatus. It is explanatory drawing which shows the mode of the process of grind | polishing a surrounding area. It is explanatory drawing which shows the mode of the grinding | polishing amount which grind | polishes a surrounding area | region. It is explanatory drawing which shows the mode of the grinding | polishing amount which grind | polishes a surrounding area | region. It is the graph which showed the relationship between abrasive injection amount and grinding depth. It is the graph which showed the relationship between abrasive injection pressure, abrasive injection amount, and grinding depth.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Solar cell film 3 Surrounding area 4 Transparent electrode layer 5 Photoelectric conversion layer 6 Back surface electrode layer 7 Photoelectric conversion cell 8 Insulating groove (X direction)
DESCRIPTION OF SYMBOLS 9 Transparent electrode layer dividing groove 10 Oscillator 11 Shutter 12 Laser beam 13 Drive apparatus 14 XY table 15 Mask 16 Cooling nozzle 17 Shutter control apparatus 18 Oscillation control apparatus 20 Blast polishing apparatus 21 Compressor 22 Injection pressure adjustment valve 23 Feeder 24 Pressure Tank 25 Cyclone 26 Dust collector 27 Nozzle 28 Blast nozzle drive device 29 Recovery hopper 30 Groove 31 Groove 32 Terminal box 33 Backsheet 50 Solar cell panel 51 First cell layer 52 Second cell layer 53 Intermediate contact layer 101 Substrate 102 Solar cell membrane 103 Surrounding region 104 Transparent electrode layer 105 Photoelectric conversion layer 106 Back electrode layer 107 Solar cell 108 Insulating groove 109 Transparent electrode layer dividing groove 110 Micro crack portion (laser mark)

Claims (10)

A photoelectric conversion unit forming step of forming a photoelectric conversion unit divided into a plurality of photoelectric conversion cells on the main surface of the translucent substrate;
After the photoelectric conversion unit forming step, a peripheral region forming step of forming a peripheral region by removing the photoelectric conversion unit formed on the peripheral portion of the main surface;
Comprising
The photoelectric conversion unit formation step includes
A transparent electrode layer forming step of forming a transparent electrode layer on the main surface of the translucent substrate;
The transparent electrode layer forming step includes
A transparent electrode layer forming step of forming the transparent electrode layer on the main surface;
A transparent electrode layer etching step of performing laser etching so that the formed transparent electrode layer is divided so as to correspond to each of the plurality of photoelectric conversion cells;
In the transparent electrode layer etching step,
The length of the line over which the laser is applied to the transparent electrode layer is beyond the end of the power generation region, which is a region from which power is extracted during power generation, and within the range of the surrounding region before removing the photoelectric conversion unit. Irradiate a laser so that the line is 10 mm or less and the line does not reach the end of the translucent substrate,
The surrounding region forming step is performed by at least two or more polishing steps.
A first polishing step that is an initial polishing step among the plurality of polishing steps , and polishes a part of the end surface side of the translucent substrate in the region to be formed of the surrounding region;
After the first polishing step, at least a second polishing step of polishing the inner side that is the power generation region side of the region polished in the first polishing step,
The method of manufacturing a photoelectric conversion device, wherein the plurality of polishing steps are performed so that the polishing amount is substantially uniform over the entire surrounding region. It is a manufacturing method of the photoelectric conversion device according to claim 1,
Furthermore,
An insulating groove etching step, which is performed after the photoelectric conversion unit forming step, and forms a groove by laser etching a part of the photoelectric conversion unit so that the translucent substrate is exposed,
Comprising
When irradiating the photoelectric conversion unit with a laser in the insulating groove etching step, the edge of the power generation region, which is a region where power is extracted during power generation, and before the photoelectric conversion unit is removed A length of a line irradiated with a laser within a range is 10 mm or less , and the laser is irradiated so that the line does not reach an end of the translucent substrate . Production method. It is a manufacturing method of the photoelectric conversion device according to claim 2,
In the surrounding area forming step, the photoelectric conversion unit is removed so that the surrounding area is formed with a width of 5 mm or more and 20 mm or less from an end portion of the translucent substrate. Method. It is a manufacturing method of the photoelectric conversion device according to claim 2 or 3,
At least one of the transparent electrode layer etching step and the insulating groove etching step is:
Obtaining irradiation position information indicating the irradiation position of the laser on the translucent substrate;
And a step of opening and closing a shutter arranged on the optical path of the laser based on the obtained irradiation position information. It is a manufacturing method of the photoelectric conversion device according to claim 2 or 3,
In at least one of the transparent electrode layer etching step and the insulating groove etching step, when irradiating a laser, irradiate a laser generated by pulse oscillation,
At least one of the transparent electrode layer etching step and the insulating groove etching step is:
Obtaining irradiation position information indicating the irradiation position of the laser on the translucent substrate;
And a step of controlling the oscillation frequency of the laser based on the obtained irradiation position information. It is a manufacturing method of the photoelectric conversion device according to claim 2 or 3,
At least one of the transparent electrode layer etching step and the insulating groove etching step is:
A mask placement step of placing a mask that blocks laser light so that a region that is not etched is covered on an extension of the line to be etched; and
And a step of irradiating at least one of the layer for performing the transparent electrode layer etching on the substrate on which the mask is disposed and the layer for performing the insulating groove etching after the mask placing step. A method for manufacturing a photoelectric conversion device. It is a manufacturing method of the photoelectric conversion device according to any one of claims 2 to 6,
At least one of the transparent electrode layer etching step and the insulating groove etching step is:
And a step of controlling the substrate temperature by spraying a gas onto the translucent substrate. It is a manufacturing method of the photoelectric conversion device according to any one of claims 1 to 7 ,
Before SL polishing amount in the second polishing step, a method for manufacturing a photoelectric conversion device, characterized in that less than polishing amount in the first polishing step. It is a manufacturing method of the photoelectric conversion device according to claim 8,
In the first polishing step and the second polishing step, polishing is performed by blast polishing,
The method of manufacturing a photoelectric conversion device, wherein a relative feed speed of the blast injection position in the second polishing step with respect to the translucent substrate is faster than a relative feed speed of the blast injection position in the first polishing step. It is a manufacturing method of the photoelectric conversion device according to claim 8,
In the first polishing step and the second polishing step, polishing is performed by blast polishing,
The blast spray pressure in the surrounding area on the translucent substrate in the second polishing step is lower than the blast spray pressure in the peripheral area on the translucent substrate in the first polishing step. A method for manufacturing a photoelectric conversion device.

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