WO2014073223A1 - Method for manufacturing solar cell, printing mask, solar cell, and solar cell module - Google Patents

Abstract

The purpose of the present invention is to obtain a method for manufacturing a solar cell capable of reducing the amount of a metallic paste constituting an electrode material while retaining the same level of power generation efficiency in the solar cell. A method for manufacturing a solar cell including a screen printing step for applying a paste containing a conductive material constituting the electrode material to the electrode-formation surface of a substrate, via a printing mask corresponding to an electrode shape having a bus electrode part and a grid electrode part, wherein the method for manufacturing the solar cell is characterized in that the screen printing step includes a step for applying the paste using the printing mask, there being used in the printing mask a screen mesh woven by arranging a larger number of filaments in the bus electrode part than in the grid electrode part.

Description

SOLAR CELL MANUFACTURING METHOD, PRINT MASK, SOLAR CELL, AND SOLAR CELL MODULE

The present invention relates to a method for manufacturing a solar cell, a printing mask, a solar cell, and a solar cell module.

Currently, solar cells constituting solar cell modules are mainly provided with electrodes on each of a front surface that is a light receiving surface of a substrate material such as silicon and a back surface on the opposite side. In recent years, solar cells in which electrodes are formed only on the back surface of both surfaces have been put into practical use, but solar cells in which electrodes are formed on both surfaces are still widely used.

For example, in patent document 1, the following procedures are employ | adopted at the time of manufacture of a solar cell. First, a reflection structure of sunlight on the surface of a substrate material such as silicon is changed, and a texture structure (unevenness) for taking the reflected light into the substrate is formed by a technique such as etching. Next, a pn bond is formed by a technique such as diffusion. Next, an antireflection film for reducing the reflection of sunlight by a light interference effect is formed on at least one surface of the substrate material using a silicon nitride film or the like. Next, a pattern is formed on the antireflection film, a metal paste is applied, the metal paste is heated, the antireflection film is melted by glass contained in the metal paste, and firing is performed for electrical connection with the substrate. To form an electrode. Further, the substrate material is immersed in an etching solution having a property of dissolving the glass component to dissolve the glass component contained in the electrode, thereby reducing the electrical resistance of the electrode.
For example, Patent Documents 2 and 3 disclose a method for manufacturing a solar cell having electrodes on both the front surface side and the back surface side of a substrate material.

Generally, as a method for forming a solar cell electrode, a simple method such as screen printing is employed. A printing mask used for screen printing is a material to be printed by fixing a base material called a screen mesh made of metal thread or chemical fiber to a mask frame, and fixing the part other than the part that allows metal paste to pass through with resin. Used for patterning.

In order to reduce the cost of the solar cell module, it is extremely difficult to realize the cost reduction of the constituent material of the solar cell, which occupies a large proportion in price. For example, it is necessary to review everything from the substrate material, which is a base material, to the materials and consumables used in each process. Among them, a metal paste material used as an electrode material is usually made of silver as a conductive metal, but it is very expensive. However, simply reducing the amount of electrode material used increases the resistance loss at the electrode and reduces the power generation efficiency of the solar cell. Therefore, it is required to reduce the amount of metal paste used without reducing the power generation efficiency of the solar cell.

In the grid electrode for collecting the current on the surface side of the solar cell, since the portion where the grid electrode is arranged does not generate power, the grid electrode width is preferably narrow. However, since the electrical resistance increases and the resistance loss increases only by reducing the electrode width, it is desirable that the grid electrode is thicker. As the thickness of the grid electrode is increased, the resistance loss is reduced and the power generation efficiency of the solar cell is improved.
When a conventional screen printing mask is used, the thickness of the electrode is determined by mask specifications such as the screen mesh wire diameter and opening width.

In the printing mask, the specifications are expressed using the number of yarns per inch (25.4 mm) used for the screen mesh (hereinafter referred to as mesh count) and the wire diameter of the yarns. For example, 200 yarns per inch and a yarn having a wire diameter of 40 μm are expressed as “200φ40”. Therefore, the larger the number, the finer the mesh, and the relatively smaller the wire diameter.

In the conventional printing mask, the screen mesh is attached to the mask frame so that the warp or weft of the screen mesh is inclined 20 to 30 degrees with respect to the grid electrode pattern. This is because when the grid electrode pattern and the yarn are parallel, the pattern edge is covered with the yarn, so that a precise electrode pattern cannot be formed.

In the solar cell module, the bus electrode of the solar cell is soldered to the back bus electrode of the adjacent solar cell with a soldered copper wire and connected in series.
In the present specification, the bus electrode refers to a bus electrode on the surface side. The electrode on the back side bus is described as the back bus electrode.
In a bus electrode for soldering and connecting solar cells with a soldered copper wire, bonding strength by soldering is required, so there is a limit to reducing the bus electrode width.
Therefore, in order to reduce the amount of metal paste used in the bus electrode, it is necessary to reduce the thickness of the bus electrode.
However, since the bus electrode thickness is determined by mask specifications such as the screen mesh wire diameter and opening width as in the case of the grid electrode, if the grid electrode thickness is increased in order to improve power generation efficiency, the bus electrode thickness is increased. It will also be thicker.
In the bus electrode, since the collected current flows on the soldered copper wire soldered on the bus electrode, increasing the thickness of the bus electrode does not reduce the resistance loss and does not improve the power generation efficiency. .

Japanese Patent No. 4486622 (see paragraph 0014) Japanese Patent No. 4319006 (see paragraph 0019) Japanese Patent No. 4481869 (see paragraph 0052)

In order to improve the power generation efficiency of the solar cell, when the thickness of the grid electrode is increased, the thickness of the bus electrode is also increased, and the amount of metal paste used is increased.
On the other hand, if the thickness of the bus electrode is reduced in order to reduce the amount of metal paste used, the thickness of the grid electrode is also reduced, resulting in a problem that the power generation efficiency of the solar cell is significantly reduced.

The present invention was made to solve the above problems, and a solar cell manufacturing method capable of reducing the amount of metal paste used as an electrode material while maintaining the same power generation efficiency of the solar cell, It aims at obtaining the printing mask used in the manufacturing method, a solar cell provided with the electrode manufactured by the manufacturing method, and a solar cell module.

In the method for manufacturing a solar cell according to the present invention, a paste containing a conductive material as an electrode material is applied to an electrode forming surface of a substrate through a print mask corresponding to the electrode shape having a bus electrode portion and a grid electrode portion. A method of manufacturing a solar cell including a screen printing process,
The screen printing step includes the step of applying the paste using the printing mask using a screen mesh in which the bus electrode portion has a larger number of yarns than the grid electrode portion and is reticulated. To do.
The printing mask of the present invention is a printing mask used when applying a paste containing a conductive material as an electrode material to the electrode forming surface of the substrate,
The screen mesh for holding the paste is characterized in that the bus electrode portion is formed by arranging yarns in a larger number than the grid electrode portion.

According to the present invention, it is possible to reduce the amount of metal paste used in the grid electrode by using a printing mask using a screen mesh in which the yarn is arranged in a larger number than the grid electrode portion in the bus electrode portion. The amount of metal paste used at the bus electrode can be reduced. Thereby, the manufacturing cost of the solar cell can be reduced while maintaining the power generation efficiency of the solar cell at the same level.

1 is an external view showing the surface of a solar cell including electrodes formed by the method for manufacturing a solar cell according to the first embodiment of the present invention. FIG. 2 is an external view showing the back surface of the solar cell. 3 is a cross-sectional view of the EE portion of the solar cell shown in FIGS. 1 and 2. FIG. FIG. 4 is a schematic cross-sectional view of a stage portion of a printing machine used in a screen printing process. FIG. 5 is an enlarged cross-sectional view of the main part of FIG. FIG. 6 is a plan view showing an example of a substrate material on which an electrode is formed by the method of Embodiment 1 of the present invention. FIG. 7 is a plan view showing an example of a substrate material on which an electrode is formed by the method of Embodiment 1 of the present invention. FIG. 8 is a top view showing a printing mask used in the screen printing process. FIG. 9 is an enlarged cross-sectional view of the FF portion of the grid electrode portion of FIG. FIG. 10 is an enlarged cross-sectional view of the GG portion of the bus electrode portion of FIG. FIG. 11 is a schematic plan view of a mask (blank) before forming an electrode pattern in the printing mask used in the method of Embodiment 1 of the present invention. FIG. 12 is an enlarged plan view showing details of the screen mesh according to the first embodiment of the present invention. 13 is a cross-sectional view of the HH portion of the screen mesh of FIG. FIG. 14 is a schematic plan view after an electrode pattern is formed on a printing mask used in the electrode forming method according to Embodiment 1 of the present invention. 15 is an enlarged plan view showing details of a part of the configuration shown in FIG. FIG. 16 is a schematic diagram enlarging a part of the grid electrode portion of the screen mesh according to the first embodiment. FIG. 17 is a list showing transmission thicknesses of grid electrode portions of the screen mesh according to the first embodiment. FIG. 18 is a schematic enlarged view of a part of the bus electrode portion of the screen mesh according to the first embodiment. FIG. 19 is a list showing transmission thicknesses of bus electrode portions of the screen mesh according to the first embodiment. FIG. 20 is a list summarizing the comparison between the conventional example and the present embodiment. FIG. 21 is an enlarged plan view showing details of the screen mesh according to the second embodiment of the present invention. 22 is a cross-sectional view of the JJ portion of the screen mesh of FIG. FIG. 23 is a list showing the angles of the densely packed portions of the screen mesh of the second embodiment where the yarns are densely packed. FIG. 24 is a list showing the widths of the dense portions where the yarns are dense, of the screen mesh of the second embodiment. FIG. 25 is a schematic cross-sectional view illustrating the procedure of the method for manufacturing the solar cell module according to Embodiment 3 of the present invention. FIG. 26 is a schematic cross-sectional view illustrating the procedure of the method for manufacturing the solar cell module according to Embodiment 3 of the present invention.

Hereinafter, embodiments of a method for forming a solar cell electrode, a printing mask, a solar cell, and a solar cell module according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
A method for forming an electrode for a solar cell, a printing mask, and a solar cell according to Embodiment 1 of the present invention will be described.
FIG. 1 is a diagram illustrating a surface that is a light-receiving surface of a solar cell including an electrode formed by the method for forming an electrode of a solar cell according to the first embodiment of the present invention. FIG. 2 is a diagram showing a back surface opposite to the light receiving surface of the solar cell shown in FIG. 3 is a cross-sectional view taken along the line EE of FIGS. A surface electrode composed of a grid electrode 21 and a bus electrode 22 is provided on the surface of the solar cell 1. The grid electrode 21 and the bus electrode 22 are orthogonal to each other.
The horizontal direction indicated by the arrow X in FIGS. 1 and 2 is the longitudinal direction of the grid electrode 21. The vertical direction indicated by the arrow Y in FIGS. 1 and 2 is the longitudinal direction of the bus electrode 22.
A back aluminum electrode 23 and a back bus electrode 24 are provided on the back surface of the solar cell 1.

FIG. 3 shows a cross-sectional view taken along the line EE of FIGS. In the figure, the upper side is a light receiving surface (surface). On the upper surface of the p-type silicon substrate 31, an n layer 32 is formed by phosphorus diffusion, and a photoelectric conversion part having a pn junction is formed. An antireflection film 33 is formed on the n layer 32. A bus electrode 22 is provided above the antireflection film 33. The antireflection film 33 under the bus electrode 22 is melted by firing, and the bus electrode 22 is in electrical contact with the n layer 32. On the back side, a back aluminum electrode 23 and a back bus electrode 24 are provided.

Next, the electrode formation method of the surface electrode of the solar cell concerning this Embodiment 1 is demonstrated. FIG. 4 is a schematic cross-sectional view of the stage portion of the printing machine used in the screen printing process. In the screen printing process, the metal paste 5 is applied to the electrode forming surface of the substrate material 3 through the printing mask 2. FIG. 5 is an enlarged view of a main part of FIG.
The printing machine shown in FIGS. 4 and 5 includes a stage 4 for placing the substrate material 3, and the stage 4 includes a suction mechanism 7 for fixing the substrate material 3. The suction mechanism 7 fixes the substrate material 3 to the stage 4 by sucking air at the stage 4.

The printing mask 2 includes a mask frame 6, a warp thread 11, and a weft thread 12, and includes a screen mesh 9 attached to the printing surface side of the mask frame 6 and a photosensitive emulsion 10.
FIG. 5 is drawn with the stage 4 and the mask frame 6 omitted.

6 and 7 are plan views showing examples of substrate materials for forming electrodes according to the first embodiment. As the substrate material 3, for example, a square shape shown in FIG. 6 or a rounded quadrangular shape having four corners of an arc as shown in FIG. 7 is used. The one side M of the square shape shown in FIG. 6 and the one side equivalent width M of the rounded square shape shown in FIG. 7 are, for example, 156 mm.

As the substrate material 3, for example, a silicon wafer that is a thin plate-like silicon is used. The substrate material 3 may be made of any material as long as an electrode can be formed by a screen printing process.

The metal paste 5 includes a conductive material as an electrode material, and the components are adjusted so as to maintain a desired viscosity. Typical conductive materials used for the metal paste 5 include gold, silver, copper, platinum and palladium. The metal paste 5 contains one or more of these conductive materials.

The printing machine applies the metal paste 5 to the electrode forming surface of the substrate material 3 through the print mask 2 by scanning the squeegee 8 on the print mask 2 on which the metal paste 5 is placed. In the printing mask 2, the metal paste 5 is not passed through the portion covered with the photosensitive emulsion 10, but the metal paste 5 is passed through the portion where the screen mesh 9 is exposed. The pattern is transferred onto the electrode forming surface.

The metal paste 5 applied to the substrate material 3 by screen printing becomes an electrode by a process generally called firing. In the baking step, heat treatment is performed so that the peak temperature is 900 ° C. or lower, preferably 750 to 800 ° C. The heat treatment time in the firing furnace is generally within 2 minutes.

When the separation of the p-type electrode and the n-type electrode (hereinafter referred to as pn separation) is performed prior to the formation of the electrode by screen printing, in order to suppress the occurrence of leakage current due to the adhesion of the electrode material, It is necessary to suppress adhesion of the metal paste 5 to 13 and to provide a margin 14. For this purpose, it is desirable to form a pattern so that the peripheral portion of the printing mask is covered with the photosensitive emulsion 10. Also, when performing pn separation by laser processing or the like after electrode formation, it is desirable to suppress adhesion of the metal paste 5 to the outer edge side surface 13 and to provide a margin 14 in order to suppress the occurrence of leakage current.

The solar cell electrode is formed by the process as described above. In addition, a solar cell is manufactured with the manufacturing method similar to the past except the formation method of the electrode for solar cells.

Next, the printing mask 2 used for electrode formation of the surface electrode of the solar cell according to the first embodiment will be described in detail.
FIG. 8 is a top view showing the printing mask 2 used in the screen printing process, and FIG. 9 is an enlarged sectional view of the FF portion (grid electrode portion) of FIG. FIG. 9 is a cross-sectional view at an angle parallel to the weft 12. The horizontal direction indicated by the arrow X in FIG. 8 is the longitudinal direction of the grid electrode 21. The vertical direction indicated by the arrow Y in FIG. 8 is the longitudinal direction of the bus electrode 22.
The screen mesh 9 has warp yarns 11, weft yarns 12 and photosensitive emulsion 10. The photosensitive emulsion 10 is provided with a grid electrode opening 41.

FIG. 10 is an enlarged cross-sectional view of the GG portion (bus electrode portion) of FIG. FIG. 10 is a cross-sectional view at an angle parallel to the weft 12.
The screen mesh 9 has warp yarns 11, weft yarns 12 and photosensitive emulsion 10. The photosensitive emulsion 10 is provided with a bus electrode opening 42.
The printing mask 2 according to the present embodiment is characterized in that the screen mesh for holding the paste is netted so that two threads are formed at the bus electrode portion.

FIG. 11 is a schematic diagram of a mask (blank) before forming an electrode pattern in the printing mask used in the electrode forming method of the first embodiment. FIG. 12 is an enlarged view of the square ABCD in FIG. The square part ABCD in FIG. 11 corresponds to the outer peripheral corner part ABCD in FIG.
The vertical direction indicated by the arrow X in FIG. 11 is the direction in which the grid electrode 21 is in the longitudinal direction. The horizontal direction indicated by the arrow Y in FIG. 11 is the direction in which the bus electrode 22 is in the longitudinal direction. FIG. 11 is a layout view in which FIG. 8 is rotated 90 degrees clockwise.
The mask (blank) is composed of a screen mesh 9 and a mask frame 6.
A screen mesh 9 is attached to the printing surface side of the mask frame 6.

A method for making the screen mesh 9 will be described with reference to FIGS.
FIG. 12 is a plan view showing a method for making the screen mesh 9. The screen mesh 9 has warp threads 111 to 120 and weft threads 131 to 140.
In the figure, in order to clarify how warp yarns are connected, diagonal lines are provided for each warp yarn.
The conventional screen mesh is netted so that the warp and weft alternate alternately, but the screen mesh 9 of the first embodiment is netted so that the top and bottom are partially continuous.

The weft 131 is below the warp 111, above the warp 112, 113, below the warp 114, above the warp 115, below the warp 116, above the warp 117, below the warp 118, above the warp 119, below the warp 120. Netted to pass through. Here, the warp yarns 112 and 113 are different from conventional nets in that they pass the upper side continuously.

FIG. 13 is a sectional view taken along line HH in FIG. It is sectional drawing in a weft 131 part.
Since the weft 131 passes below the warp 111 and above the warp 112, the position of the weft 131 is changed from the bottom to the top between the warp 111 and the warp 112. Therefore, a certain distance is required between the warp yarn 111 and the warp yarn 112 in order to pass the weft 131. Usually, the interval between the warp yarn 111 and the warp yarn 112 needs to be about 2 to 4 times the diameter of the weft yarn 131.

On the other hand, since the weft 131 passes over the warp 112 and the warp 113, the position does not change between the warp 112 and the warp 113. Accordingly, the distance between the warp yarn 112 and the warp yarn 113 is not limited at the position of the weft yarn 131 and can be brought close to each other.

The weft 132 is above the warp 111, below the warp 112, 113, above the warp 114, below the warp 115, above the warp 116, below the warp 117, above the warp 118, below the warp 119, above the warp 120. Netted to pass through. Here, the warp yarns 112 and 113 are different from conventional nets in that they pass continuously on the lower side.

The weft 133 is below the warp 111, above the warp 112, below the warp 113, 114, above the warp 115, below the warp 116, above the warp 117, below the warp 118, above the warp 119, below the warp 120. Netted to pass through. Here, the warp yarns 113 and 114 are different from the conventional nets in that they pass through the lower side continuously.

When attention is paid to the place where the weft passes continuously above or below the warp, the following is obtained.
The weft 131 passes above the warp yarns 112 and 113.
The weft 132 passes under the warp yarns 112 and 113.
The weft thread 133 passes below the warp threads 113 and 114.
The weft yarn 134 passes above the warp yarns 113 and 114.
The weft 135 passes below the warps 113 and 114.
The weft thread 136 passes under the warp threads 114 and 115.
The weft thread 137 passes above the warp threads 114 and 115.
The weft 138 passes under the warp yarns 114 and 115.
The weft 139 passes below the warp yarns 115 and 116.
The weft yarn 140 passes above the warp yarns 115 and 116.

Since the distance between the warp yarns can be reduced at the place where the warp yarns pass on the same side, the following is a focus on the distance between the warp yarns.
At the position of the weft 131, the warps 112 and 113 can be brought close to each other.
At the position of the weft 132, the warps 112, 113 can be brought closer.
At the position of the weft thread 133, the warp threads 113 and 114 can be brought close to each other.
At the position of the weft yarn 134, the warp yarns 113 and 114 can be brought close to each other.
The warp yarns 113 and 114 can be brought close to each other at the position of the weft yarn 135.
At the position of the weft 136, the warps 114, 115 can be brought close to each other.
At the position of the weft thread 137, the warp threads 114 and 115 can be brought close to each other.
At the position of the weft thread 138, the warp threads 114 and 115 can be brought close to each other.
At the position of the weft thread 139, the warp threads 115 and 116 can be brought close to each other.
At the position of the weft 140, the warps 115, 116 can be brought closer.

By configuring in this way, the distance between the warp yarns can be reduced, so that the warp yarns can be arranged more densely than the conventional example. That is, the number of warp yarns per unit length can be increased.

When paying attention to the warp, the warp 113 is at the same upper side as the warp 112 at the position of the weft 132 and is therefore close to the warp 112. Since the weft 133 is on the same upper side as the warp 114, it is close to the warp 114.
That is, the position of the warp yarn 113 is shifted from the warp yarn 112 side to the warp yarn 114 side at an intermediate position 161 between the weft yarn 132 and the weft yarn 133.
Similarly, the position of the warp yarn 114 is shifted from the warp yarn 113 side to the warp yarn 115 side at an intermediate position 162 between the weft yarn 135 and the weft yarn 136.
Similarly, the position of the warp yarn 115 is shifted from the warp yarn 114 side to the warp yarn 116 side at an intermediate position 163 between the weft yarn 138 and the weft yarn 139.

In this way, by forming a net so that the warp yarns that are continuous every three weft yarns are shifted laterally, a dense portion 150 where the distance between the warp yarns is short is formed diagonally as in the region surrounded by the broken line in FIG. be able to. The dense spot 150 is continuously formed in the Y direction from the upper end to the lower end of the mesh.
An angle formed by the dense portion 150 and warps other than the dense portion is defined as θ2.

In the present embodiment, the example in which the continuous warp yarns are shifted to the side for every three weft yarns has been described, but it is not limited to every three weft yarns. Any configuration such as every one weft, every two wefts, every four wefts, every five wefts, etc. may be used.
By changing this configuration, the angle θ2 of the densely-packed portion 150 formed obliquely can be changed.

FIG. 14 is a schematic view after the electrode pattern is formed in the printing mask used in the electrode forming method of the first embodiment. FIG. 15 is an enlarged view of a part of FIG.
The vertical direction indicated by the arrow X in FIG. 14 is the longitudinal direction of the grid electrode 21. The horizontal direction indicated by the arrow Y in FIG. 14 is the longitudinal direction of the bus electrode 22.

As shown in FIGS. 14 and 15, the printing mask 2 is obtained by coating and forming a pattern of the photosensitive emulsion 10 on the screen mesh 9, and the screen mesh 9 and the photosensitive emulsion 10 covering a part of the screen mesh 9. And a mask frame 6.
The photosensitive emulsion 10 has an opening 20 composed of a grid electrode opening 41 and a bus electrode opening 42. The grid electrode openings 41 are arranged so that the vertical direction and the X direction in FIG. The bus electrode openings 42 are arranged so that the horizontal direction and the Y direction in FIG.

The screen mesh 9 is affixed to the mask frame 6 by rotating from the arrangement of FIG. 12 so that the dense location 150 overlaps the bus electrode opening 42. When rotated clockwise (θ2 + 90 °) from the arrangement of FIG. 12, the Y direction becomes the horizontal direction and overlaps with the bus electrode opening 42 of FIG.

In the pattern of FIG. 14, four bus electrode openings 42 are provided. Four dense places 150 are provided on the screen mesh 9 so as to overlap the four places, and the dense places 150 are rotated and pasted so as to be in the horizontal direction, and then the bus electrode openings 42 are arranged at the dense places. It may be installed according to 150.

Thus, by arranging the dense locations 150 of the screen mesh 9 and the bus electrode openings 42 so as to coincide with each other, the warp yarns can be densely arranged only at the positions of the bus electrode openings 42.

According to the printing mask 2, as shown in FIG. 5, the metal paste 5 is blocked from passing through the portion covered with the photosensitive emulsion 10, and the metal paste 5 is applied to the portion where the screen mesh 9 is exposed, that is, the opening 20. Let it pass. The mask frame 6 holds the photosensitive emulsion 10 and the screen mesh 9.

The configuration of the printing mask 2 may be appropriately changed as long as it has characteristics suitable for screen printing for electrode formation. For example, the printing mask 2 generally uses stainless steel as a screen mesh material, but instead of stainless steel, a screen mesh made of a synthetic fiber material or a screen mesh made of a metal material other than stainless steel is used. It may be what you do. The printing mask 2 may be used by attaching a metal member pattern to a screen mesh in place of the photosensitive emulsion 10.

The discharge amount of the metal paste that passes through the screen mesh 9 will be described with reference to FIGS. 16 and 18.
FIG. 16 shows an enlarged schematic view of a part of the grid electrode portion of the screen mesh of the first embodiment. In the first embodiment of the present invention, the configuration of the screen mesh of the grid electrode portion is the same as the configuration of the conventional screen mesh.
The warp yarns 401 and 402 are formed with a warp yarn wire diameter Dv1.
The warp yarns 401 and 402 are arranged at an interval of the warp yarn opening width Wv1.
The warp pitch Pv1 is a total value of the warp opening width Wv1 and the warp wire diameter Dv1.

The weft yarns 403 and 404 are formed with a weft yarn diameter Dh1.
The wefts 403 and 404 are arranged with an interval of the weft opening width Wh1.
The weft pitch Ph1 is a total value of the weft opening width Wh1 and the weft wire diameter Dh1.
The weft 403 passes below the warp yarn 401 and passes above the warp yarn 402.
The weft 404 passes above the warp 401 and passes below the warp 402.
Generally, the warp yarn diameter Dv1 and the weft yarn diameter Dh1 are the same. Further, the warp opening width Wv1 and the weft opening width Wh1 are the same.

As an index indicating the amount of paste discharged from the screen mesh, an index called transmission thickness is used. The transmission thickness will be described based on FIG.
After the screen mesh is removed, the paste filled in the screen mesh opening by the thickness of the screen mesh (= thickness) spreads to the place where the screen mesh was present due to surface tension. The thickness becomes thinner than that.
The thickness after the paste spreads is called the transmission thickness. Although it is an index generally referred to as a permeation volume or a permeation volume, it is an index having a dimension of length, and is referred to as a permeation thickness in this specification. The transmission thickness is expressed by the following equation.
Permeation thickness = (opening area × 紗 thickness) / (warp pitch Pv1 × weft pitch Ph1)
Opening area = warp opening width Wv1 x weft opening width Wh1
Warp pitch Pv1 = warp yarn opening width Wv1 + warp yarn wire diameter Dv1
Weft pitch Ph1 = Weft opening width Wh1 + Weft wire diameter Dh1

紗 Thickness is usually the same as (warp yarn diameter + weft yarn diameter). A screen mesh that has been crushed after knitting yarn can have a thickness of about 50% of the warp wire diameter + the weft wire diameter.

FIG. 17 shows a list of calculated transmission thicknesses of the grid electrode part.
The warp yarn diameter Dv1 and the weft yarn diameter Dh1 were the same. The warp opening width Wv1 and the weft opening width Wh1 were the same.
In addition, since the structure of the conventional screen mesh is the same as the structure of the screen mesh of a grid electrode part, the permeation | transmission thickness of the conventional screen mesh also becomes the same thickness.
A1 is “200φ40”. In A1, since 200 yarns are arranged per 25.4 mm, the pitch is 25.4 mm / 200 = 127 μm. The opening width is equal to the value obtained by subtracting the wire diameter from the pitch. In A1, since the wire diameter is 40 μm, the opening width is 87 μm. The thickness is assumed to be equal to the thickness of a general screen mesh. The thickness shown in FIG. 17 is that of a general screen mesh.
In A1, the transmission height is 29.6 μm.
A2 is “250φ30”. In A2, the transmission height is 22.8 μm.
A3 is “290φ20”. In A3, the transmission height is 20.8 μm.
A4 is “360φ16”. In A4, the transmission height is 16.7 μm.

FIG. 18 shows an enlarged schematic view of a part of the bus electrode portion of the screen mesh according to the first embodiment.
The warp yarns 441, 442, 443, and 444 are formed with the warp wire diameter Dv2.
The warp yarn 443 and the warp yarn 444 are arranged with the warp yarn adjacent width Wv3.
Similarly, the warp yarn 441 and the warp yarn 442 are arranged with the warp yarn adjacent width Wv3.
The warp yarn 442 and the warp yarn 443 are arranged with a warp yarn opening width Wv2.
The warp pitch Pv2 is a total value of two warp opening width Wv2, warp adjacent width Wv3, and warp wire diameter Dv1.

The weft yarns 445 and 446 are formed with a weft yarn wire diameter Dh2.
The weft 445 and the weft 446 are arranged with a weft opening width Wh2.
The weft 445 passes below the warp yarns 441 and 442 and passes above the warp yarns 443 and 444.
The weft 446 passes above the warp yarns 441 and 442 and passes below the warp yarns 443 and 444.
The weft pitch Ph2 is a total value of the weft opening width Wh2 and the weft wire diameter Dh2.
Generally, the warp yarn diameter Dv2 and the weft yarn diameter Dh2 are the same. The warp opening width Wv2 and the weft opening width Wh2 are the same.

In the first embodiment, the transmission thickness is expressed by the following equation.
Permeation thickness = (opening area × 紗 thickness) / (warp pitch Pv2 × weft pitch Ph2)
Opening area = (warp yarn opening width Wv2 + warp yarn adjacent width Wv3) × weft yarn opening width Wh2
Warp pitch Pv2 = warp yarn opening width Wv2 + warp yarn adjacent width Wv3 + 2 × warp yarn wire diameter Dv2
Weft pitch Ph2 = weft opening width Wh2 + weft wire diameter Dh2

FIG. 19 shows a list of calculated transmission thicknesses of the screen mesh according to the present embodiment.
The adjacent ratio is a ratio between the warp adjacent width Wv3 and the warp wire diameter Dv2.
When the adjacent ratio is 0, it indicates that the two warps are closely arranged.
When the adjacency ratio is 0.5, it indicates that the two warp yarns are arranged with an interval of half the wire diameter of the warp yarns.
The warp yarn opening width Wv2 and the weft yarn opening width Wh2 were the same as the opening widths Wv1 and Wh1 of the grid electrode portion.

B1 is the case where the wire diameter and opening width are the same as “200φ40”, and two warps are closely arranged. In B1, the transmission height is 22.5 μm.
B2 is the case where the same wire diameter and opening width as “250φ30” are used, and two warp yarns are closely arranged. In B2, the transmission height is 17.6 μm.
B3 is the case where the wire diameter and opening width are the same as “290φ20”, and two warps are closely arranged. In B3, the transmission height is 17.0 μm.
B4 is the case where the wire diameter and opening width are the same as “360φ16”, and two warp yarns are closely arranged. In B4, the transmission height is 13.6 μm.
C1 is the case where the same wire diameter and opening width as “200φ40” are used, and two warps are arranged with half the wire diameter open. In C1, the transmission height is 20.1 μm.
C2 is the case where the same wire diameter and opening width as “250φ30” are used, and two warps are arranged with half the wire diameter open. In C2, the transmission height is 15.8 μm.
C3 is the case where the wire diameter and opening width are the same as “290φ20”, and two warps are arranged with half the wire diameter open. In C3, the transmission height is 15.5 μm.
C4 is the case where the same wire diameter and opening width as “360φ16” are used, and two warps are arranged with half the wire diameter open. In C4, the transmission height is 12.5 μm.

FIG. 20 shows a table summarizing comparison of transmission thicknesses of the grid electrode portion and the bus electrode portion.
Since the configuration of the screen mesh of the grid electrode portion is the same as the configuration of the conventional screen mesh, FIG. 20 is also a comparison of the transmission thickness of the bus electrode portion of the conventional example and the first embodiment.
The transmission thickness ratio is a ratio of the transmission thickness of the bus electrode portion to the transmission thickness of the grid electrode portion.
With a wire diameter of 40 μm and an opening width of 87 μm, the transmission thickness of the bus electrode portion is reduced to 76% when two warps are closely arranged. When two warp yarns are arranged with half the wire diameter open, the transmission thickness is reduced to 84%.
With a wire diameter of 30 μm and an opening width of 72 μm, if two warps are arranged closely, the transmission thickness of the bus electrode portion is reduced to 77%. When two warp yarns are arranged with half the wire diameter open, the transmission thickness is reduced to 84%.
With a wire diameter of 20 μm and an opening width of 68 μm, the transmission thickness of the bus electrode portion is reduced to 81% when two warps are closely arranged. When two warp yarns are arranged with half the wire diameter open, the transmission thickness is reduced to 86%.
With a wire diameter of 16 μm and an opening width of 55 μm, the transmission thickness of the bus electrode portion is reduced to 82% when two warps are closely arranged. When two warp yarns are arranged with half the wire diameter open, the transmission thickness is reduced to 86%.
As described above, according to the first embodiment, the bus electrode transmission thickness can be reduced without changing the transmission thickness of the grid electrode.

As shown in FIGS. 12 and 15, the screen mesh 9 used for the printing mask 2 is arranged so that the dense location 150 and the bus electrode opening 42 overlap each other.
By arranging in this way, the transmission thickness at the bus electrode can be reduced without changing the transmission thickness of the metal paste 5 at the grid electrode. That is, the amount of the metal paste 5 used at the bus electrode can be reduced without changing the shape of the grid electrode.
For example, when two warps are arranged with a half of the wire diameter with a wire diameter of 20 μm and an opening width of 68 μm, the amount of metal paste used in the bus electrode is reduced to 86% as the transmission thickness decreases. be able to.
In the first embodiment, the effect when the wire diameter of the warp and the wire diameter of the weft is the same has been described. However, the same effect can be obtained when the wire diameter of the warp and the wire diameter of the weft are changed. The diameter and the wire diameter of the weft may be changed.

Thus, by densely arranging the warp yarns so that the two yarns are on the same side, it is possible to form a dense portion where the warp yarns are partially densely arranged. By arranging the dense locations and the bus electrode openings so as to coincide with each other, the paste is applied to a substrate material such as silicon by using a screen mesh in which a larger number of threads are arranged in the bus electrode portion than in the grid electrode portion. The amount of metal paste used for the bus electrode can be reduced without changing the amount of paste used for the grid electrode. Thereby, the usage-amount of a metal paste can be reduced, keeping the electric power generation efficiency of a solar cell comparable.

In the electrode forming method according to the first embodiment of the present invention, by using the above-described printing mask, it is possible to reduce the amount of metal paste used for the front bus electrode even if a conventional printing machine is used. . For this reason, according to the present embodiment, it is possible to obtain a reduction in the amount of metal paste used by a screen printing method similar to the conventional method except that the printing mask is changed. Moreover, the electrode formation method of this invention can be easily implemented by adding to the specification of a printing mask with respect to the method of a comparative example. The electrode forming method of the present invention is particularly useful for an electrode on the light receiving surface side of a solar cell.

By using the electrode forming method according to the first embodiment of the present invention, by using a printing mask using a screen mesh in which a larger number of yarns are arranged in the bus electrode portion than in the grid electrode portion, the grid electrode is used. The amount of metal paste used at the bus electrode can be reduced without reducing the amount of metal paste used at the bus. Thereby, the manufacturing cost of the solar cell can be reduced while maintaining the power generation efficiency of the solar cell at the same level.

As described above, the solar cell manufacturing method, the printing mask, and the solar cell according to the present embodiment are useful for reducing the cost of the solar cell.

Embodiment 2. FIG.
The printing mask according to the second embodiment of the present invention will be described in detail.
The solar cell electrode forming method and solar cell according to the second embodiment of the present invention are the same as those of the first embodiment except for the print mask and the electrode shape formed thereby.

21 and 22 show the configuration of the screen mesh 501 according to the second embodiment of the present invention, in which the configuration in which the warp yarns are continuous is changed.
The second embodiment is different from the first embodiment in that a plurality of adjacent portions of warp yarns are continuously provided.
FIG. 21 is a diagram showing a method for making the screen mesh 501. The screen mesh 501 has warps 511 to 520 and wefts 531 to 540.
The weft 531 is netted so as to pass under the warp yarns 511 and 512, above the warp yarns 513 and 514, below the warp yarns 515 and 516, above the warp yarns 517 and 518, below the warp yarn 519, and above the warp yarn 520. That is, the nets are formed so that four sets of warp yarns continuously passing on the same side are arranged adjacent to each other.

FIG. 22 is a sectional view taken along line JJ in FIG. It is sectional drawing in a weft 531 part.
Since the weft 531 passes under the warp 512 and above the warp 513, the position of the weft 531 is changed from the bottom to the top between the warp 512 and the warp 513. Accordingly, the gap between the warp yarn 512 and the warp yarn 513 requires a certain amount of space in order to pass the weft yarn 531.

Similarly, since the weft 531 passes above the warp 514 and below the warp 515, the position is changed from the top to the bottom between the warp 514 and the warp 515. Accordingly, the gap between the warp yarn 514 and the warp yarn 515 needs a certain distance in order to pass the weft yarn 531.

Similarly, since the weft 531 passes under the warp 516 and above the warp 517, a certain distance is required between the warp 516 and the warp 517 in order to pass the weft 531.
In addition, since the weft 531 passes over the warp 518 and under the warp 519, the warp 518 and the warp 519 need a certain distance to pass the weft 531.

On the other hand, since the weft 531 passes under the warp 511 and the warp 512, the position does not change between the warp 511 and the warp 512. Therefore, there is no restriction | limiting in the space | interval of the warp yarn 511 and the warp yarn 512, and it can approach.

Similarly, since the weft 531 passes over the warp 513 and the warp 514, the position does not change between the warp 513 and the warp 514. Therefore, the distance between the warp yarn 513 and the warp yarn 514 is not limited and can be approached.
Further, since the weft 531 passes under the warp 515 and the warp 516, the distance between the warp 515 and the warp 516 is not limited and can be made closer.
Further, since the weft 531 passes over the warp 517 and the warp 518, the distance between the warp 517 and the warp 518 is not limited and can be made closer.

When attention is paid to the location where the weft thread passes continuously above or below the warp thread, it is as follows.
The weft 531 passes below the warp yarns 511 and 512, above the warp yarns 513 and 514, below the warp yarns 515 and 516, and above the warp yarns 517 and 518.
The weft 532 passes above the warp yarns 511 and 512, below the warp yarns 513 and 514, above the warp yarns 515 and 516, and below the warp yarns 517 and 518.
The weft 533 passes below the warp yarns 511 and 512, above the warp yarns 513 and 514, below the warp yarns 515 and 516, and above the warp yarns 517 and 518.
The weft 534 passes below the warp yarns 512 and 513, above the warp yarns 514 and 515, below the warp yarns 516 and 517, and above the warp yarns 518 and 519.
The weft 535 passes above the warp yarns 512 and 513, below the warp yarns 514 and 515, above the warp yarns 516 and 517, and below the warp yarns 518 and 519.
The weft 536 passes below the warp yarns 512 and 513, above the warp yarns 514 and 515, below the warp yarns 516 and 517, and above the warp yarns 518 and 519.
The weft 537 passes below the warp yarns 513 and 514, above the warp yarns 515 and 516, below the warp yarns 517 and 518, and above the warp yarns 519 and 520.
The weft 538 passes above the warp yarns 513 and 514, below the warp yarns 515 and 516, above the warp yarns 517 and 518, and below the warp yarns 519 and 520.
The weft 539 passes below the warps 513, 514, above the warps 515, 516, below the warps 517, 518, and above the warps 519, 520.
The weft 540 passes below the warp yarns 514 and 515, above the warp yarns 516 and 517, below the warp yarns 518 and 519, and above the warp yarn 520.

Since the distance between the warp yarns can be reduced at the place where the warp yarns pass on the same side, the following is a focus on the distance between the warp yarns.
At the positions of the weft yarns 531, 532, 533, the warp yarns 511, 512 can be brought close to each other. Moreover, the warp yarns 513 and 514 can be brought close to each other. Moreover, the warp yarns 515 and 516 can be brought close to each other. Moreover, the warp yarns 517 and 518 can be brought close to each other.
At the positions of the weft yarns 534, 535, and 536, the warp yarns 512 and 513 can be brought close to each other. Moreover, the warp yarns 514 and 515 can be brought close to each other. Further, the warps 516 and 517 can be brought close to each other. Moreover, the warp yarns 518 and 519 can be brought close to each other.
At the positions of the weft yarns 537, 538, 539, the warp yarns 513, 514 can be brought close to each other. Moreover, the warp yarns 515 and 516 can be brought close to each other. Moreover, the warp yarns 517 and 518 can be brought close to each other. Moreover, the warp yarns 519 and 520 can be brought close to each other.
At the position of the weft 540, the warps 514, 515 can be brought closer to each other. Further, the warps 516 and 517 can be brought close to each other. Moreover, the warp yarns 518 and 519 can be brought close to each other.

By comprising in this way, since the space | interval of a warp yarn can be closely approached, a warp yarn can be arrange | positioned more densely than a prior art example. That is, the number of warp yarns per unit length can be increased.
Moreover, since the places where the warp yarns are densely arranged can be formed continuously, the width of the places where the warp yarns are densely arranged can be freely set.

When paying attention to the warp, the warp 512 is located on the same upper side as the warp 511 at the position of the weft 533, and thus is close to the warp 511. Since the position of the weft 534 is on the same upper side as the warp 513, it is close to the warp 513.
That is, the position of the warp yarn 512 is shifted from the warp yarn 511 side to the warp yarn 513 side at an intermediate position between the weft yarn 533 and the weft yarn 534.
Similarly, the position of the warp yarn 513 is shifted from the warp yarn 512 side to the warp yarn 514 side at an intermediate position between the weft yarn 536 and the weft yarn 537.
Similarly, the position of the warp yarn 514 is shifted from the warp yarn 513 side to the warp yarn 515 side at an intermediate position between the weft yarn 533 and the weft yarn 534. Further, the position is shifted from the warp yarn 513 side to the warp yarn 515 side at an intermediate position between the weft yarn 539 and the weft yarn 540.

In this way, by forming the net so that the warp yarns that are continuous every three weft yarns are shifted laterally, the dense portion 550 in which the distance between the warp yarns is short is formed diagonally as in the region surrounded by the broken line in FIG. be able to. The dense spot 550 is continuously formed in the Y direction from the upper end to the lower end of the mesh.

The angle and width of the crowded area 550 are calculated.
When the warp cycle for shifting the warp yarns to the side is Nh2 and the warp yarn continuous group in which the warp yarns are continuous is Nv2, the crowded portion angle θ2 that is an angle formed by the warp yarn and the crowded portion 550, and the crowded portion angle θ2 of the crowded portion 550. The crowded portion width L2 which is the width in the direction perpendicular to is expressed as follows.
tan θ2 = Pv2 / (Nh2 × Ph2)
cos θ2 = (Nv2 × Pv2) / L2

FIG. 23 shows a calculation example of the crowded portion angle θ2 when the warp period Nh2 is changed.
The weft yarn pitch Ph2 and the warp yarn pitch Pv2 were calculated under the condition of C3 in FIG. In this example, the weft pitch Ph2 is 88 μm and the warp pitch Pv2 is 118 μm.
When the warp period Nh2 is increased, the crowded portion angle θ2 is decreased. In the state of three warp cycles in FIG. 21, the crowded portion angle θ2 is 24.1 °.

The warp period Nh2 need not be constant over the entire length in the Y direction. For example, by alternately providing two warp cycles and three warp cycles, the dense portion angle θ1 is between 33.9 ° when the warp cycle is 2 and 24.1 ° when the warp cycle is 3 can do.
In this manner, by adjusting the warp yarn period, it is possible to realize an arbitrary crowded portion angle θ2.

FIG. 24 shows a calculation example of the crowded portion width L2 when the warp yarn period Nh2 and the warp yarn continuous set Nv2 are changed.
The weft yarn pitch Ph2 and the warp yarn pitch Pv2 were calculated under the condition of C3 in FIG. In this example, the weft pitch Ph2 is 88 μm and the warp pitch Pv2 is 118 μm.
When the warp cycle Nh2 is 3, and the warp yarn continuous set Nv2 is 15, the crowded portion width L2 is 1932 μm≈1.9 mm.

That is, when the bus width is 2 mm, the wire diameters Dv2 and Dh2 are 20 μm, the warp opening width Wv2, the weft opening width Wh1 is 68 μm, the warp adjacent width Wv3 is 10 μm, the warp period Nh2 is 3, and the warp continuous group Nv2 is 15 sets. Then, the stainless steel mesh is rotated by (24.1 + 90) ° and attached to the printing mask, so that the bus opening and the dense portion can be arranged to coincide with each other.

In consideration of the positioning accuracy of the bus electrode opening and the dense portion width, it is desirable that the dense portion width is slightly smaller than the bus electrode width.

As described above, according to the second embodiment of the present invention, by forming the warp so that the two yarns are partially on the same side, a dense portion where the warp yarns are partially arranged is formed. Can do.
In addition, since the places where the warp yarns are densely arranged can be formed continuously, the dense portion width which is the width of the place where the warp yarns are densely arranged can be freely selected.
In addition, by changing the warp yarn period in which the warp yarns are laterally shifted and the warp yarn continuous set in which the warp yarns are continuous, the dense point angle θ2 that is an angle formed by the warp yarns and the dense points can be freely selected.
By arranging the dense locations and the bus electrode openings so as to coincide with each other, the paste is applied to a substrate material such as silicon by using a screen mesh in which a larger number of threads are arranged in the bus electrode portion than in the grid electrode portion. The amount of metal paste used for the bus electrode can be reduced without changing the amount of paste used for the grid electrode. Thereby, the usage-amount of a metal paste can be reduced, keeping the electric power generation efficiency of a solar cell comparable.

In the electrode forming method according to the second embodiment of the present invention, the use amount of the metal paste used for the front bus electrode can be reduced by using the above-described printing mask even if a usual printing machine is used. . For this reason, according to the present embodiment, it is possible to obtain a reduction in the amount of metal paste used by a screen printing method similar to the conventional method except that the printing mask is changed. Moreover, the electrode formation method of this invention can be easily implemented by adding to the specification of a printing mask with respect to the method of a comparative example. The electrode forming method of the present invention is particularly useful for an electrode on the light receiving surface side of a solar cell.

By using the electrode forming method according to the second embodiment of the present invention, by using a printing mask using a screen mesh in which a larger number of yarns are arranged in the bus electrode portion than in the grid electrode portion, the grid electrode is used. The amount of metal paste used at the bus electrode can be reduced without reducing the amount of metal paste used at the bus. Thereby, the manufacturing cost of the solar cell can be reduced while maintaining the power generation efficiency of the solar cell at the same level.
In addition, since the places where the warp yarns are densely arranged can be formed continuously, the dense portion width which is the width of the place where the warp yarns are densely arranged can be freely selected.
Further, by changing the warp yarn period in which the warp yarns are shifted laterally and the warp yarn continuous set in which the warp yarns are continuous, the dense portion angle, which is the angle formed by the warp yarns and the dense portions, can be freely selected.

As described above, the solar cell manufacturing method, the printing mask, and the solar cell according to the second embodiment are useful for reducing the cost of the solar cell.

Embodiment 3 FIG.
A solar cell module according to Embodiment 3 of the present invention will be described in detail.
25 and 26 are schematic cross-sectional views illustrating the procedure of the method for manufacturing the solar cell module according to the third embodiment. The upper side of FIGS. 25 and 26 is the light receiving surface side.
FIG. 25 is a diagram of the solar cell module installed state and a state where the upper side is the light receiving surface side. When assembling the solar cell module, the top and bottom of FIG. 25 are reversed.
First, the translucent resin member 16 is installed on the translucent substrate 15. The translucent resin member 16 is provided with a solar cell 17 with wiring. The solar cell with wiring 17 has a predetermined number of solar cells 1 (see FIG. 1) created by using the first embodiment or the second embodiment of the present invention arranged in parallel, and is adjacent to the bus electrode of the solar cell. The back bus electrode of the battery is formed by soldering with a soldered copper wire and connecting the wires in series.
The material used for the wiring may be any conductive material other than the copper wire with solder.
The solar cell with wiring 17 is installed on the translucent resin member 16 with the back surface of each solar cell 1 facing upward and the front surface facing the translucent substrate 15.

Further, a translucent resin member 16 and a back sheet 18 are installed on the solar cell 17 with wiring. FIG. 25 shows a state in which the translucent substrate 15, the translucent resin member 16, the solar cell 17 with wiring, the translucent resin member 16, and the back sheet 18 are stacked in order from the top of the figure.

By performing a heat treatment in a state where these members are pressure-bonded, as shown in FIG. 26, a translucent resin layer 19 in which the solar cell with wiring 17 is sealed, a translucent substrate 15, and a back sheet. A solar cell module integrated with 18 is produced. By using the solar cell 1 provided with the electrode formed by the method for forming a solar cell electrode according to the first or second embodiment of the present invention, the metal paste while maintaining the power generation efficiency of the solar cell at the same level The manufacturing cost of the solar cell module can be lowered by reducing the usage amount of the solar cell module and the manufacturing cost of the solar cell module.

It is desirable to use a vacuum thermocompression bonding device called a laminator for the heating and pressure bonding treatment in the production of the solar cell module. The laminator heat-deforms the translucent resin member 16 and the back sheet 18 and further integrates them by thermosetting, and seals the solar cell in the translucent resin layer 19.

The vacuum thermocompression bonding apparatus heats and crimps each member in a reduced pressure environment. Thereby, between the translucent board | substrate 15 and the translucent resin member 16, between the translucent resin member 16 and the solar cell 17 with a wiring, between the solar cell 17 with a wiring, and the translucent resin member 16, a translucent resin member 16 and the back sheet 18 can prevent gaps and bubbles from remaining, and can press the members with uniform pressure.

The heating and pressure-bonding process in the vacuum thermocompression bonding apparatus is performed at a temperature of 200 degrees or less, preferably 150 to 200 degrees. It is assumed that the temperature in the heating and pressure bonding processes can be appropriately changed depending on the material of the translucent resin member 16 and the like.

As the translucent substrate 15, for example, a glass substrate is used. The translucent board | substrate 15 should just be able to permeate | transmit sunlight, and is good also as what consists of materials other than glass. The translucent resin member 16 is one of resins such as ethylene vinyl acetate, polyvinyl butyral, epoxy, acrylic, urethane, olefin, polyester, silicon, polystyrene, polycarbonate, and rubber. Contains one or more. As long as the translucent resin member 16 can transmit sunlight, any material other than those listed here may be used.

As the back sheet 18, a sheet made of one or a plurality of resins such as polyester, polyvinyl, polycarbonate and polyimide is used. The back sheet 18 may be made of any material other than those listed here as long as it has sufficient strength, moisture resistance and weather resistance for protecting the solar cell module. The back sheet 18 may be made of not only a resin material but also a composite material obtained by bonding metal foil materials in order to improve strength, moisture resistance, and weather resistance. Further, the back sheet 18 may be formed by bonding a metal material having a high reflectance or a transparent member having a high refractive index to a resin material by vapor deposition or the like.

The end face of the solar cell module may be protected with a tape made of a rubber-based resin member or the like in order to improve the adhesiveness of the laminating process and prevent moisture from entering from the outside. For example, butyl rubber or the like is used as the rubber-based resin member. Furthermore, the solar cell module may be provided with a frame that surrounds the outer periphery in view of ease of handling as a structure. The frame is configured using a metal member such as aluminum or an aluminum alloy, for example.

By the electrode forming method according to the first embodiment or the second embodiment, the third embodiment can obtain an inexpensive solar cell module by a simple method without significantly changing the method of the comparative example. This is very useful industrially.

1 solar cell, 2 printing mask, 3 substrate material, 4 stage, 5 metal paste, 6 mask frame, 7 suction mechanism, 8 squeegee, 9 screen mesh, 10 photosensitive emulsion, 11 warp, 12 weft, 13 outer edge, 14 margins, 15 translucent substrate, 16 translucent resin member, 17 solar cell with wiring, 18 back sheet, 19 translucent resin layer, 20 opening, 21 grid electrode, 22 bus electrode, 23 back aluminum electrode, 24 back bus electrode, 31 p-type silicon substrate, 32 n layer, 33 antireflection film, 41 grid electrode opening, 42 bus electrode opening, 111-120 warp, 131-140 weft, 150 crowded location, 161 warp 113 Intermediate position between weft 132 and weft 133, weft 135 and weft of warp 114 Intermediate position with 136, 163 intermediate position between weft 138 and weft 139 of warp 115, 401, 402 warp, 403, 404 weft, 441, 442, 443, 444 warp, 445, 446 weft, 501 screen mesh, 511- 520 warp yarns, 531-540 weft yarns, 550 dense locations, Dv1 warp wire diameter, Wv1 warp opening width, Pv1 warp pitch, Dh1 weft wire diameter, Wh1 weft opening width, Ph1 weft pitch, Dv2 warp wire diameter, Wv2 warp opening width, Wv3 Warp Thread Adjacent Width, Pv2 Warp Thread Pitch, Dh2 Weft Thread Diameter, Wh2 Weft Thread Opening Width, Ph2 Weft Thread Pitch, Nh2 Warp Thread Period, Nv2 Warp Yarn Continuous Set, θ2 Concentration Location Angle, L2 Concentration Location Width.

Claims (8)

1. Solar cell manufacturing method including screen printing step of applying paste containing conductive material as electrode material to electrode forming surface of substrate through printing mask corresponding to electrode shape having bus electrode portion and grid electrode portion Because
   The screen printing step includes the step of applying the paste using the printing mask using a screen mesh in which the bus electrode portion has a larger number of yarns than the grid electrode portion and is reticulated. A method for manufacturing a solar cell.
2. The screen mesh warp and weft are alternately made up and down, and a plurality of warp yarns are partially positioned on the same side of the upper side or the lower side, and the positions of the weft yarns that are continuous with the warp yarns are sequentially shifted. 2. The sun according to claim 1, wherein the printed mask is formed by forming the densely packed portions of the warp yarns obliquely and arranging a bus electrode pattern in accordance with the densely located portions. Battery manufacturing method.
3. The method for manufacturing a solar cell according to claim 1 or 2, wherein the printing mask is used in which the number of continuous warps is two on the same side.
4. A printing mask used when applying a paste containing a conductive material as an electrode material to an electrode forming surface of a substrate,
   A printing mask comprising a screen mesh for holding the paste, in which a string is formed by arranging a larger number of yarns in a bus electrode portion than in a grid electrode portion.
5. In the printing mask having the screen mesh in which warp yarns and weft yarns are alternately made up and down, a plurality of the warp yarns are continuously located on the same side of the upper side or the lower side, and the warp yarns are continuous. 5. The printing mask according to claim 4, wherein by shifting the position of the weft yarn in order, the dense portions where the warp yarns are continuous are formed obliquely, and a bus electrode pattern is arranged in accordance with the dense portions.
6. The printing mask according to claim 4 or 5, wherein the number of continuous warp yarns on the same side is two.
7. A solar cell formed by using the method for manufacturing a solar cell according to claim 1.
8. A solar cell module, wherein a plurality of solar cells according to claim 7 are arranged, and the adjacent solar cells are connected to each other by bus electrodes formed by the printing mask.

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