JP2004207575A - Solar battery panel and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery panel with high productivity by obtaining a substrate for ensuring the strength withstanding a stress caused by the self-weight of the substrate itself and a thermal stress acting on the substrate so as to reduce the probability of destruction, and also to provide a manufacturing method of the solar battery panel. <P>SOLUTION: In the solar battery panel wherein a plurality of solar battery films are layered on the substrate 1, semi-cylindrical R-chamfer process is applied to an end of the substrate 1 so as to ensure the strength withstanding self-weight deformation and a thermal stress acting on the substrate 1. Further, the manufacturing method of the solar battery panel is built up, wherein the substrate receiving the R-chamfer process is subjected to film forming processing and thereafter the resulting substrate is split as required. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solar cell panel used for photovoltaic power generation and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, solar energy has been known as clean energy that does not adversely affect the environment and ecosystem. In using solar energy, solar cells that convert sunlight into electricity have been widely used in recent years. Such a solar cell is generally known as a solar cell panel configured in a plate shape so as to increase power generation efficiency by sunlight.
[0003]
To briefly explain the structure of a solar cell panel, a solar cell panel has a structure in which a plurality of films such as a transparent electrode film, a semiconductor film, and a metal electrode film are stacked on a transparent substrate such as soda glass. A protective sealant for sealing these solar cell films (transparent electrode film, semiconductor film, metal electrode film) is provided at the peripheral end. Also, the solar cell films referred to above are generally covered with an adhesive sheet, a cover glass, or the like.
[0004]
In manufacturing such a solar cell panel, if there is a chip at the edge of the substrate, there is a problem that the substrate such as glass is chipped when the semiconductor layer is removed. Therefore, in order to avoid this, it has already been disclosed that it is desirable to form the semiconductor layer in a polygonal shape or an arc shape so that the corners of the surface on which the semiconductor layer is formed have substantially no right angle or acute angle portion ( See Patent Document 1.).
[0005]
[Patent Document 1]
Japanese Patent No. 3243229 (18th and 21st paragraphs, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, the chamfering of the substrate end disclosed in the above-mentioned conventional technique is difficult to mechanically remove the substrate surface on which the film forming process has been performed, if the substrate end is not chamfered. This is performed because there is a problem that chipping becomes a defect. When a defect occurs at the edge of the substrate, there is a possibility that the substrate may be split from the defective portion due to a thermal stress caused by a variation in the temperature distribution of the solar cell panel. The thermal stress referred to here is generated due to heat input in a usage condition by sunlight, and is greatly different from a thermal stress in a heat treatment required in a manufacturing process such as a film forming process.
[0007]
Here, with reference to the drawings, a description will be given of the thermal stress generated on the substrate by the heat treatment with the substrate heating heater. As shown in the graph of FIG. 5, when the deformation is constrained by fixing the outer peripheral portion of the substrate, the relationship between the maximum temperature difference in the plane that is the extending direction of the substrate and the generated thermal stress is as follows. As the temperature difference on the substrate surface increases, the thermal stress generated on the substrate increases proportionately. The thickness of the substrate used in the analysis shown in the graph was 4 mm, and the size was about 1 m square.
[0008]
According to the measurement result of the temperature of the solar cell panel when heated by receiving sunlight, the temperature rises by about 50 ° C. from about 30 ° C. in the morning to about 80 ° C. in the noon in summer, and about 0 ° C. in the morning in winter. 50 ° C. increase from 50 ° C. to 50 ° C. during the day. Thus, the temperature rise does not change in summer and winter, and the heat load applied to the panel is considered to be equivalent. This temperature rise does not mean that the solar radiation at midday is suddenly received, and the heating is moderate, so that the temperature difference in the substrate surface hardly occurs. However, the panel temperature also changes when the sunlight is suddenly blocked by the clouds. In this case, the temperature change of the solar cell panel is about 20 ° C. in midsummer and about 10 ° C. in midwinter, and the temperature difference in the substrate surface caused by this temperature change is 20 ° C. or less. When this temperature difference is compared with the graph of FIG. 5, the stress generated in the substrate is 1 kgf / mm ² or less.
[0009]
However, in the heat treatment at around 200 ° C. during the film formation of the substrate, the temperature difference on the substrate surface can easily exceed 50 ° C. In this case, the thermal stress generated on the substrate is caused by the heat input of sunlight. It is likely that about 3 kgf / mm ^{2, which} is larger than the thermal stress caused by the above, will also act. That is, in a manufacturing process such as a film forming process, since a difference between a normal temperature range before heating and a temperature range after heating is large, a large variation easily occurs in a temperature distribution on a substrate surface, and as a result, Large thermal stress is likely to occur. Of course, one method is to reduce the temperature difference between the substrates by improving the heating method using a heater for heating the substrate and the like, and to heat the heating means for uniformly heating the substrate having a larger area. The method and configuration can also increase the size and cost of the device.
[0010]
Further, as shown in a graph showing the relationship between the temperature difference between the front and back surfaces of the substrate and the generated thermal stress in FIG. 6, when a difference in temperature occurs between the front surface and the back surface of the substrate when the substrate is heated, the temperature distribution is reduced. It is conceivable that the variation causes a thermal stress to warp the substrate. This thermal stress increases proportionally as the temperature difference between the front and back surfaces increases as shown in the figure.
[0011]
Even in this case, the temperature difference generated between the front and back of the solar cell panel due to the heat input of sunlight is small, and the generated thermal stress is small. On the other hand, in the heating of about 200 ° C. by deposition process or the like, the temperature difference of the substrate is likely that exceeding 50 ° C., by this, thermal stress of great about 2 kgf / mm ² strength than the generation stress Is likely to act on the substrate.
[0012]
Further, the substrate heated for performing the film forming process is returned to room temperature at a certain stage, but at this time, a large amount of heat is generated at the edge of the substrate as compared with the center side of the substrate. A large temperature difference is likely to occur between the end and the center. This is also true when heating.
[0013]
This will be described based on the analysis result shown in the graph of FIG. FIG. 7 shows a change in generated stress in the axial direction (extending direction of the substrate edge) with time when a substrate uniformly heated to 180 ° C. is left in an environment at normal temperature (20 ° C.). Things.
[0014]
According to this, read that axial stress increases rapidly every time, after lapse of 60 seconds generated in an end portion about 0.7 kgf / mm ² of the thermal stress is the maximum value of the substrate of the thermal stress are doing. This is caused by a large difference in temperature between the end of the substrate and the center because the heat dissipation speed of the end of the substrate is higher than that of the center of the substrate.
[0015]
As described above, in the heat treatment in the process of manufacturing a solar cell panel such as film formation, a large amount of heat is applied to the substrate. There is a need for a substrate having a strength that can withstand the above.
[0016]
Further, the prior art does not disclose a processing shape for preventing a defect at an end portion of a substrate from being caused by a load applied by the substrate's own weight or the like when the substrate is transported in a solar cell panel manufacturing process.
[0017]
Also, when trying to increase the area of the substrate, the weight of the substrate itself increases, so that a large amount of stress due to its own weight acts on the lower end of the substrate in the transfer process, There is a high possibility that the substrate will be broken such that the substrate is cracked.
[0018]
The present invention has been made in view of the above circumstances, and reduces the probability of destruction by obtaining a substrate that has sufficient strength to withstand the stress generated by the substrate's own weight and the thermal stress acting on the substrate, thereby reducing productivity. It is an object of the present invention to provide a solar cell panel with high reliability and a method for manufacturing a solar cell panel.
[0019]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is characterized in that in a solar cell panel in which a solar cell film composed of a plurality of films is laminated on a substrate, an R-chamfering process is performed on an end of the substrate.
[0020]
According to a second aspect of the present invention, in the solar cell panel according to the first aspect, the shape obtained by the R-chamfering processing is a semi-cylindrical shape.
[0021]
According to such a configuration, the thermal stress due to the weight caused by the weight of the substrate, the thermal stress due to the variation in the temperature distribution in the heat treatment in the manufacturing process such as the case of forming a film, or the thermal stress due to the variation in the temperature distribution in the heat radiation action. , Etc., the substrate has sufficient strength on the end side to withstand these stresses, and breakage such as cracking is avoided. In addition, since the cross-sectional shape at the end of the substrate is formed in a semi-cylindrical shape by the R chamfering, the strength is accurately secured, and defects are less likely to occur at the end.
[0022]
The invention according to claim 3 is a method for manufacturing a solar cell panel in which a solar cell film including a plurality of films is stacked on a substrate, wherein the edge of the substrate is subjected to an R chamfering process, and then the solar cell film is manufactured. It is characterized by applying a film.
[0023]
According to such a manufacturing method, even if a thermal stress occurs in the substrate due to a difference in the temperature distribution of the substrate when the substrate is heated during film formation, the strength capable of withstanding the thermal stress by the R chamfering process of the end portion is increased. Since the substrate has the substrate, the substrate is not damaged by heat treatment during film formation. That is, the problem in the heat treatment can be eliminated by manufacturing a solar cell panel by forming a substrate that can withstand the thermal influence during film formation in advance. This means that the substrate after the film is formed is subjected to a R-chamfering process so that the substrate is formed for the purpose of avoiding generation of defects in the strength against heat input by sunlight and the manufacturing process after the film formation. to differ greatly.
[0024]
According to a fourth aspect of the present invention, in the method for manufacturing a solar cell panel according to the third aspect, the solar cell panel on which the solar cell film is formed is divided to form a small solar cell panel. And
[0025]
According to such a manufacturing method, a film is formed on a substrate whose strength is ensured by performing R chamfering, and the substrate on which the film is formed is divided to form a small solar cell panel. Therefore, even when a relatively large substrate is used to manufacture a small solar cell panel, the substrate can be divided in a film-formed state without damaging the substrate.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 shown in FIG. 1 is a soda glass substrate, which is a component of a solar cell panel. As shown in FIG. 1A, the substrate 1 is a large-area substrate 1 having a size of 1.1 m × 1.4 m and a thickness of 4 mm.
FIG. 1B shows a cross section taken along line AA of FIG. 1 (a) and a cross section taken along line BB of FIG. 1 (b). Are the same.) As shown in the figure, the edges of all four sides of the substrate 1 are subjected to an R chamfering process with a radius r.
[0027]
Describing the R chamfering shown in FIG. 1B in detail, the center of this rounded shape is on the center line in the thickness direction of the substrate 1, and the rounding radius r is r = 2.5 according to 4 mm of the substrate thickness. ３3 mm. That is, by defining the rounding radius r = 2.5 to 3 mm larger than the substrate thickness of 4 mm, the cross-sectional shape of the end portion of the substrate 1 is formed in a “kamaboko shape”.
[0028]
In addition, the above-mentioned R chamfering process is obtained, for example, by abutting a disc-shaped polishing jig having an arc-shaped concave portion having a radius r set on the outer periphery thereof and polishing the same. However, the present invention is not limited to this.
[0029]
In the above-described R-chamfering processing of the substrate end, the distance between the processed end and the processed end opposite to this end is determined by the dimension of the substrate 1 of the solar cell panel as a product ( In this case, it is needless to say that it is formed so as to satisfy the dimension of 1.1 m or 1.4 m.).
[0030]
Now, regarding the characteristics of the substrate 1 on which the edge of the substrate has been subjected to the rounded chamfering process, a comparison between the substrate 1 and the substrate subjected to the C chamfering process with the C chamfering dimension of 1 mm will be described below. Will be described.
[0031]
FIG. 2 measures the frictional resistance of the ends of the two test substrates 1a and 1b (the R-chamfered test substrate 1a and the C-chamfered test substrate 1b), which are assumed to be the above-described respective substrates. It is the schematic of the structure which showed the test apparatus for forming a defect | defect and the chip | tip which becomes a defect in the edge part of each test board | substrate 1a and 1b produced by resistance (it is also called "a chip | chip"). (A) is a front view, and (b) is a side view of (a).
[0032]
Each of the test substrates 1a and 1b is arranged on the surface plate 21 so that the extending direction is upright with respect to the surface of the surface plate 21, and the holding metal fittings 22 installed on the surface plate 21 are attached to the test substrates 1a and 1b. Be pinched. A silicon nitride plate 23 (20 mm × 20 mm × 6 mm) simulating a friction coefficient of about 0.7 in a vacuum is brought into contact with upper ends of the test substrates 1 a and 1 b. Further, on the upper surface of the silicon nitride plate 23, the pressing jig 26 is pressed against located this upward load F _N in the vertically downward by the pressing jig 26, the substrate 1a through the silicon nitride plate 23 , 1b.
[0033]
Further, the side surface of the silicon nitride plate 23, connecting rod 25 disposed in the lateral direction are connected, the lateral load F _H is applied through the load cell 24 to the connecting rod 25. That is, by acting lateral load F _H silicon nitride plate 23 which is pressed in the vertical direction, rubbing the contact portion between the lower surface of the silicon nitride plates 23 test substrate 1a, an upper end 1b, the frictional force Occurs.
Incidentally, the load _{F N} to load vertically downward relative to the surface plate 21 was set to 147N and 294 N. These figures take the former into account for a substrate mass of 15 kg, and the latter take into account twice the substrate mass.
[0034]
The test results of the frictional resistance may be changed depending on the degree of the polishing process on the end surface, and thus the description is omitted. However, the test substrate 1a with the R chamfered in this test and the test substrate with the C chamfered are used. At each of the end portions 1b and 1b, a very slight "chip" (defect) was generated to the extent that it was not visible. When observing the degree of the chipping with a micrograph, the degree of the chipping is smaller in the test substrate 1a with the R chamfering, and the sharp chipping is formed at the obtuse corner in the test substrate 1b with the C chamfering. It was confirmed that the occurrence was relatively large.
That is, it was confirmed that the degree of the defect was smaller in the case of the end shape of the R chamfer than in the case of the end shape of the C chamfer.
[0035]
Now, the strength of each of the test substrates 1a and 1b obtained in the test for measuring such frictional resistance is confirmed by a four-point bending test as shown in the schematic diagram of FIG. In this test, the test substrates 1a and 1b were chamfered, and the ends rubbed with the silicon nitride plate 23 were placed on the lower side, and the 180 mm ends were separated by a spacing of 160 mm. It is installed on both support portions S1 and S2. Then, a load such that the total load becomes a load P at two force points from above the test substrates 1a and 1b is applied between the support portions S1 and S2 to the test substrates 1a and 1b. 3 (b) and 3 (c) show the dimensions and shapes of the test substrates 1b and 1a as viewed from arrow C in FIG. 3 (a).
[0036]
The results of the above-described four-point bending test are shown in a graph showing the relationship between stress and fracture probability shown in FIG. 4, and the results are summarized below.
[0037]
Considering the thermal stress already described in the problem to be solved by the present invention, and assuming that this stress value is 3 kgf / mm ² , the material indicated by the thick solid line rounded in a semicircular shape is obtained. In (test substrate 1a), it can be seen that the destruction probability is 4 × 10 ⁻⁴ .
On the other hand, in the material (test substrate 1b) indicated by the bold broken line with the C chamfer, it can be read that the fracture probability is 1.5 × 10 ⁻² at the same stress value.
In this way, the substrate that has been chamfered has a much lower probability of breaking than the substrate that has been chamfered, and this relationship can be read even when thermal stress is further applied.
[0038]
In addition, it has already been confirmed by experiments that the substrate subjected to the R chamfering is less likely to have a defect or a chipping as compared to the substrate subjected to the C chamfering, or that the degree of the chipping is small. explained. Considering this, referring to the graph of FIG. 4, the probability of destruction in the four-point bending test of the test substrates 1a and 1b in which the chipping has occurred after the measurement test of the frictional resistance has been determined. Although a slight increase in the probability of destruction due to the formation is recognized, it can be confirmed that the probability is lower than that of the C-chamfered material.
[0039]
Further, referring to the graph of FIG. 4, when a vertical load of 147 N is applied in the measurement test of the frictional resistance, even if a stress of ^{2 to} 6 kgf / mm ² is applied, no crack is present. It was confirmed that the fracture probability was almost the same as that of the case described above, and a favorable result was obtained in which the fracture probability was much lower than in the case where the C chamfer was performed.
Further, when a vertical load of 294N is applied in consideration of a load acting dynamically such as at the time of conveyance, even if a stress of 3 kgf / mm ² is applied to the substrate, the probability of destruction is 3 × 10 ⁻³ , and C Good results were obtained with a lower probability of failure than when chamfering was applied.
[0040]
As described above, according to the substrate 1 on which the radius r = 2.5 to 3 mm and the rounded chamfering process is performed, a relatively large stress acts on the substrate itself due to its own weight during the transfer. For the substrate 1 placed in a state where it may be damaged by a large thermal stress due to heat treatment such as film formation in a manufacturing process, a strength capable of withstanding this stress is secured to reduce the probability of destruction. It has become possible to greatly reduce it. Therefore, the area of the substrate can be increased, and the productivity of the solar cell panel can be greatly improved.
[0041]
When manufacturing a small-sized solar cell panel, a large-sized substrate whose one side exceeds 1 m is formed into a film, and a cover glass or the like is attached, and then divided to form a small-sized solar cell panel. Can be easily performed. In other words, it is possible to stably manufacture a substrate that is easily damaged due to cracking or the like because it is a large-area type, and manufactures a small-sized solar cell panel by dividing the large-sized substrate easily and by reducing steps. Will be able to
[0042]
【The invention's effect】
The solar cell panel of the present invention described above has the following effects.
According to the first and second aspects of the present invention, the edge of the substrate is rounded so that the strength of the substrate is increased. It is possible to obtain a favorable solar cell panel in which the probability of destruction is reduced while ensuring high strength that can withstand the occurrence of stress in a situation or heat treatment or the like. This is most effective especially for a large-sized substrate in which the probability of destruction of the substrate tends to increase. In addition, by forming the shape into a semi-cylindrical shape as the R-chamfering process, the strength can be accurately secured, and the occurrence of defects can be prevented, so that a decrease in the strength can be more accurately avoided.
[0043]
According to the third aspect of the present invention, a method of manufacturing a solar cell panel in which a solar cell film is formed after performing an R chamfering process on an end portion of the substrate. Even if a difference occurs and a thermal stress acts on the substrate, it is possible to manufacture the solar cell panel accurately and reliably without damaging the substrate by securing the strength that can withstand the thermal stress. In addition, by performing R chamfering at a stage before film formation, it is possible to avoid the occurrence of defects in the substrate during the transport process when performing the film forming process, and to accurately and correctly mount the solar cell panel without damaging the substrate. It is possible to reliably manufacture. Further, by improving the strength of the substrate as described above, it is possible to manufacture a large-area solar cell panel by increasing the size of the substrate.
[0044]
According to the fourth aspect of the present invention, a film is formed on the substrate subjected to the chamfering process, and the substrate can be divided to form a small solar cell panel. By reliably obtaining and dividing without causing damage, it is possible to manufacture and provide a small-sized solar cell panel at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic view of a substrate used for a solar cell panel according to an embodiment of the present invention, wherein (a) is a perspective view of the substrate, and (b) is a cross section AA and a cross section B- of (a). It is sectional drawing of the board | substrate edge part in which the rounded chamfer shape in B was given.
FIGS. 2A and 2B are schematic diagrams showing a schematic configuration of a test apparatus for forming a defect at a substrate end while measuring a frictional resistance at the substrate end; FIG. 2A is a front view, and FIG. is there.
FIGS. 3A and 3B are schematic diagrams schematically showing a four-point bending test on the substrate, and FIGS. 3B and 3C are projection views showing the dimensions and shapes of the test substrates in the direction of arrow C in FIG. .
FIG. 4 is a graph showing the relationship between the stress acting on the substrate and the probability of destruction of the substrate.
FIG. 5 is a graph showing a relationship between a temperature difference on a substrate surface and a generated thermal stress.
FIG. 6 is a graph showing a relationship between a temperature difference between front and back surfaces of a substrate and a generated thermal stress.
FIG. 7 is a graph showing a change in axial stress over time at the end of the substrate where the temperature decreases.
[Explanation of symbols]
Reference Signs List 1 substrate 1a test substrate 1b subjected to rounded chamfering test substrate b test substrate r subjected to C chamfering rounding radius

Claims (4)

In a solar cell panel in which a solar cell film composed of a plurality of films is laminated on a substrate,
A solar cell panel, wherein an end of the substrate is subjected to R chamfering from a first surface to a second surface facing the first surface. The solar cell panel according to claim 1,
The solar cell panel is characterized in that the shape obtained by the R chamfering processing is a semi-cylindrical shape. In a method for manufacturing a solar cell panel in which a plurality of solar cell films are stacked on a substrate,
A method of manufacturing a solar cell panel, comprising: forming a solar cell film after performing an R-chamfering process from a first surface at an end of the substrate to a second surface facing the first surface. The method for manufacturing a solar cell panel according to claim 3,
A method for manufacturing a solar cell panel, comprising dividing a solar cell panel on which a solar cell film is formed to form a small-sized solar cell panel.

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