JP2005039209A - Reinforcement method for solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcement method for a solar cell, capable of providing a solar cell mechanical strength and sufficiently preventing the mechanical degradation of the solar cell; a photopolymer composite for reinforcing the solar cell, a sheet-like photopolymer composite, and the manufacturing method of a reinforced solar cell; and the usage of the photopolymer composite for reinforcing the solar cell. <P>SOLUTION: The reinforcement method for the solar cell is to provide the layer of the photopolymer composite on the light receiving surface and/or the back surface of the solar cell having a light receiving surface electrode and a back surface electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for reinforcing a solar cell, a photosensitive resin composition and a sheet-shaped photosensitive resin composition for reinforcing the solar cell, a method for producing a reinforced solar cell, and a method for reinforcing the solar cell. It relates to the use of the photosensitive resin composition.

  In recent years, solar power generation systems have been attracting attention for global environmental problems and energy problems, especially the global warming, and the high cost efficiency technology that has been introduced into mass production processes and solar cell efficiency technologies. An excellent technique and a manufacturing process technique are required (see, for example, Non-Patent Documents 1 and 2).

There are various types of solar cells, which are roughly divided into silicon and compounds. Silicon is divided into a crystal system and an amorphous system, and the crystal system includes a single crystal and a polycrystal. The compound has a single crystal and polycrystalline, GaAs system as a single crystal, the polycrystalline CdS, CdTe, and the like CulnGaSe _2. Most of the solar cells are single crystal silicon / polycrystalline silicon / amorphous silicon, and each of them is characterized by high efficiency and abundant resources but high cost. Cost reduction is indispensable for the spread of photovoltaic power generation systems, and it is necessary to reduce the cost of silicon wafers. Therefore, the specific gravity has shifted to polycrystalline silicon, but polycrystalline silicon is more efficient than single crystalline silicon. There is a tendency to be inferior. Amorphous silicon is a product developed to reduce manufacturing costs, and single crystal silicon and polycrystalline silicon do not consume energy in the manufacturing process but tend to have the lowest efficiency. Therefore, it can be said that a polycrystalline silicon solar cell having an excellent balance between cost performance and efficiency is the mainstream of the present solar cell.

  In the manufacture of polycrystalline silicon solar cells, first, an ingot obtained by melting and re-solidifying a silicon raw material with a crucible is cut into blocks and cut with a wire saw to produce a silicon wafer. Next, the silicon wafer is etched (removed surface damage layer), diffusing agent is applied (PN junction formation), antireflection film is formed, back surface and front surface (light receiving surface) electrodes are formed, and solder coating is performed. Crystalline silicon solar cells are manufactured.

  Since the output per solar cell is small, a solar cell is used as a module by connecting a plurality of cells. A solar cell module is made by connecting a number of solar cells that can obtain a required voltage in series, and packaging with glass, film, transparent resin, or the like in order to provide weather resistance and mechanical strength.

Tatsuo Saga and two others, “High efficiency of crystalline solar cells”, Sharp Technical Report, April 2001, No. 79, p. 49-52 Shintaro Hashimoto, “Opening the Future with a Solar Power Generation Business”, Sharp Technical Journal, August 2002, No. 83, p. 40-44

  However, with the recent reduction in cost of solar cells due to cost reduction, there is a problem that the solar cells are mechanically deteriorated particularly in the module manufacturing process.

  An object of the present invention is to solve the above-described problems, and can provide a solar cell with mechanical strength and can sufficiently prevent mechanical deterioration of the solar cell. Of a reinforcing resin method, a photosensitive resin composition and a sheet-like photosensitive resin composition for reinforcing a solar battery cell, a method for producing a reinforced solar battery cell, and a photosensitive resin composition for reinforcing a solar battery cell Is to provide use.

  In order to achieve the above object, the present invention provides a solar cell characterized in that a layer of a photosensitive resin composition is provided on the light receiving surface and / or the back surface of a solar cell provided with a light receiving surface electrode and a back electrode. A method for reinforcing a cell is provided.

  According to the reinforcing method of the present invention, the layer of the photosensitive resin composition is formed on the solar battery cell, so that the mechanical strength of the solar battery cell is improved, and mechanical deterioration such as damage to the solar battery cell is caused. It can be sufficiently prevented. In addition, the reinforced solar battery cell reinforced by the above-described reinforcing method is unlikely to be mechanically deteriorated during the manufacturing (production) process of the solar battery module. Therefore, the productivity of the solar cell module can be improved.

Here, especially when the solar battery cell is a thin film type, the mechanical strength of the solar battery cell is sufficiently improved by the reinforcing method, and mechanical deterioration is sufficiently prevented. Moreover, as the solar cell, Si, GaAs, CdTe, include at least one kind of semiconductor element-type solar cells selected from the CulnGaSe _2.

  In the reinforcing method, the layer of the photosensitive resin composition is provided on the light receiving surface and / or the back surface of the solar battery cell, and the layer of the photosensitive resin composition is provided as the layer of the photosensitive resin composition. It is preferable to provide a thickness not less than the thickness of the light receiving surface electrode or the back electrode provided on the surface and not more than the thickness of the solar battery cell. Moreover, when providing the layer of the said photosensitive resin composition on the said light-receiving surface and a back surface, the thickness of the layer of the photosensitive resin composition on the said light-receiving surface is the photosensitive resin composition on the said back surface. It is preferable to provide the thickness within a range of ± 10% of the thickness of the layer.

  Moreover, when providing the layer of the said photosensitive resin composition on the said back surface, it is preferable to provide the layer of the said photosensitive resin composition so that a part of said back electrode may be exposed. Further, when the photosensitive resin composition layer is provided on the light receiving surface, the photosensitive resin composition layer may be provided as necessary so that a part of the light receiving surface electrode is exposed. preferable.

  The layer of the photosensitive resin composition provided by the reinforcing method preferably has a light transmittance of 85% or more in the visible light region. When the layer of the photosensitive resin composition satisfies such a condition, the solar battery cell can sufficiently absorb sunlight, and the energy efficiency of the solar battery cell can be maintained at a high level.

  The present invention also provides a photosensitive resin composition for reinforcing a solar cell by laminating on a light receiving surface and / or a back surface of a solar cell provided with a light receiving surface electrode and a back electrode, and the photosensitive resin composition. The present invention provides a sheet-like photosensitive resin composition characterized by forming a product into a sheet shape, and use of such a photosensitive resin composition.

  The photosensitive resin composition comprises (A) a polymer binder (more preferably a vinyl polymerization polymer binder having an acid value of 10 to 46 mgKOH / g), and (B) at least one ethylenically unsaturated group in the molecule. It is preferable to contain a photopolymerizable compound having a double bond and (C) a photopolymerization initiator.

  Moreover, it is preferable that the said sheet-like photosensitive resin composition is a sheet | seat in which the external shape process or the window opening process was made | formed. By using such a sheet-like photosensitive resin composition, the electrode of the solar battery cell can be easily exposed and used. As a result, the productivity of the solar cell module can be further improved.

  Further, the present invention provides a sheet-like photosensitive resin composition comprising the sheet-like photosensitive resin composition of the present invention laminated on the light-receiving surface and / or the back surface of a solar cell provided with a light-receiving surface electrode and a back-surface electrode. A method for producing a reinforced solar cell, characterized by curing an object.

  According to the reinforcing method of the present invention, it is possible to sufficiently prevent mechanical deterioration such as damage to solar cells. Further, according to the use of the photosensitive resin composition for reinforcing the solar battery cell of the present invention, the sheet-like photosensitive resin composition, and the photosensitive resin composition for reinforcing the solar battery cell, the solar battery cell The solar cell can be easily reinforced without lowering the energy efficiency. Moreover, according to the manufacturing method of the reinforced solar cell of this invention, the solar cell comprised so that mechanical deterioration, such as a damage, can fully be prevented can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding thereto, (meth) acrylate means acrylate and corresponding methacrylate, (meth) acryloyl group means acryloyl group and The corresponding methacryloyl group is meant.

  In the solar cell reinforcing method of this embodiment, first, a photosensitive resin composition layer (not cured) is laminated on the light receiving surface and / or the back surface of the solar cell. Next, the photosensitive resin composition layer is cured to provide a layer (cured product) of the photosensitive resin composition. Here, the photosensitive resin composition layer may be laminated by applying a solution of the photosensitive resin composition on the solar battery cell, and by arranging the sheet-like photosensitive resin composition on the solar battery cell. You may laminate.

  In addition, when using a sheet-like photosensitive resin composition, the photosensitive resin composition layer (non-cured sheet-like photosensitive resin is formed on the light-receiving surface and / or the back surface of the solar battery cell while keeping the pressure below atmospheric pressure. The photosensitive resin composition layer is preferably laminated by a lamination method in which the composition) is bonded.

  According to the above laminating method, since the photosensitive resin composition layer before curing has appropriate tackiness, it becomes possible to easily bond the photosensitive resin composition layer before curing and the solar battery cell, Furthermore, sufficient adhesiveness is obtained by the anchor effect. Moreover, it becomes possible to prevent that an air void mixes between a photovoltaic cell and the photosensitive resin composition layer by bonding together under atmospheric pressure.

  Moreover, it is preferable that the said lamination | stacking method performs the bonding of the photosensitive resin composition layer on the light-receiving surface and / or back surface of a photovoltaic cell within the vacuum apparatus provided with the elastic body inside. That is, in the above laminating method, the photosensitive resin composition layer is applied to the light receiving surface and / or the back surface of the solar battery cell in the vacuum device while keeping the inside of the vacuum device having the elastic body on the inside at a pressure lower than the atmospheric pressure. It is preferable to carry out by combining them. By bonding the photosensitive resin composition layer to the solar battery cell in a vacuum apparatus, it becomes easy to make the condition below atmospheric pressure. In addition, an elastic body is provided inside the vacuum apparatus, and the solar battery cell and the photosensitive resin composition layer are pressed against each other by the elastic body at the time of bonding. Therefore, there is no mechanical deterioration of the solar battery cell in the production process of the solar battery module, and no damage or the like occurs, so that the productivity is excellent.

  For example, the apparatus shown in FIG. 1 is used for bonding the photosensitive resin composition layer to the solar battery cell. FIG. 1 is a schematic diagram illustrating an example of a bonding apparatus used in a method for reinforcing solar cells. In the apparatus shown in FIG. 1, a transport roll B1 is disposed at one end and a take-up roll B2 is disposed at the other end. A lower base film B3 is movably attached to the transport roll B1 and the take-up roll B2. The lower base film B3 is supported with a predetermined tension by tension rolls B4, B5, and B6, and can move without causing deflection by these rolls. In the laminating apparatus, an upper base film A3 is disposed to face a part of the lower base film B3, and the upper base film A3 is attached to the transport roll A1 and the take-up roll A2 at both ends thereof. The upper base film A3 is also supported by tension rolls A4, A5, and A6 with a predetermined tension, and can move without causing deflection by these rolls.

  In the apparatus shown in FIG. 1, a set table 1, a vacuum device 2, a film moving chuck 3, and a roll 4 are arranged in this order along the lower base film B3 from the upstream in the moving direction of the lower base film B3. The vacuum apparatus 2 includes hot plates (vacuum / heating / pressurizing hot plates) 2a and 2b, and the hot plate 2a is movable in a predetermined direction. In the present embodiment, the heating plates 2a and 2b are arranged so that the base films A3 and B3 can be sandwiched by the movement of the heating plate 2a. Further, the hot plates 2a and 2b are configured to be hermetically sealed by being combined with each other. Inside the hot plates 2a and 2b, a housing part (not shown) is formed so as to accommodate solar cells, and an elastic body (for example, a diaphragm) is provided in the housing part.

  As described above, in the apparatus shown in FIG. 1, the base films A3 and B3 for transporting the substrate are attached to the transport roll A1 and the transport roll B1. 10-100 micrometers is preferable, as for the film thickness of base film A3, B3, it is more preferable that it is 15-50 micrometers, and it is still more preferable that it is 20-30 micrometers. If the film thickness of the base film is less than 10 μm, there is a tendency that the base film is easily cut during the conveyance of the substrate, and if the film thickness of the base film exceeds 100 μm, the thermal conductivity to the substrate in a certain time tends to decrease. . The base films A3 and B3 are fed by the moving amount of the film moving chuck 3.

The solar battery cell used in the present embodiment is a solar battery cell containing a semiconductor compound, such as a semiconductor element type solar battery made of silicon (single crystal, polycrystalline, amorphous), GaAs, CdTe, CulGaSe ₂ or the like. Is mentioned. The thinner the solar cell, the lower the cost, but the mechanical strength tends to be significantly inferior as it is, and sufficient solar power can be obtained by laminating the photosensitive resin composition layer as in this embodiment. The mechanical strength of the battery cell can be obtained. Here, especially when the solar battery cell is a thin film type, the mechanical strength of the solar battery cell is sufficiently improved by the reinforcing method, and mechanical deterioration is sufficiently prevented.

  As shown in FIG. 2, the solar battery cell 10 has a light receiving surface (front surface) 11 a and a back surface 11 b on which a light receiving surface electrode 13 such as silver or aluminum and a back surface electrode 15 are formed. That is, in the solar cell 10, the light receiving surface electrode 13 and the back surface electrode 15 are formed on the light receiving surface 11 a and the back surface 11 b of the substrate 11, respectively. For example, in the case of a crystalline silicon solar cell, the substrate 11 is formed by forming a pn junction and an antireflection film on a silicon wafer.

  The photosensitive resin composition layer used in this embodiment is preferably obtained by applying and drying a solution of a photosensitive resin composition (described in detail later) on a base film (support) called a photosensitive film. used. That is, the photosensitive resin composition in the photosensitive film which has a support body and the photosensitive resin composition layer (sheet-like photosensitive resin composition) in which the photosensitive resin composition was formed in the sheet form on this support body. Layer can be used. In this photosensitive film, a protective film may be present on the surface of the photosensitive resin composition layer opposite to the base film (support).

  More specifically, the above laminating methods include the following first, second, and third laminating methods.

That is, the first lamination method is
(1-1) a step of introducing solar cells into the vacuum device 2 provided with an elastic body inside;
(1-2) a step of setting the photosensitive resin composition layer on the light receiving surface (front surface) and / or the back surface of the solar battery cell introduced into the vacuum device 2;
(1-3) A step of evacuating the inside of the vacuum device 2 in which the solar cells are introduced;
(1-4) supplying atmospheric pressure or pressurized fluid from the outside of the elastic body provided in the vacuum device 2.

The second lamination method is
(2-1) A step of introducing a solar battery cell in which a photosensitive resin composition layer is set in advance in a vacuum device 2 provided with an elastic body on the inside;
(2-2) A step of evacuating the inside of the vacuum apparatus 2 in which the solar cells are introduced;
(2-3) supplying atmospheric pressure or pressurized fluid from the outside of the elastic body provided in the vacuum device 2.

The third lamination method is
(3-1) a step of introducing solar cells while setting the photosensitive resin composition layer in the vacuum device 2 provided with an elastic body inside;
(3-2) A step of evacuating the inside of the vacuum device 2 in which the solar cells are introduced;
(3-3) supplying atmospheric pressure or pressurized fluid from the outside of the elastic body provided in the vacuum device 2.

  In the steps (1-3), (2-2), and (3-2) described above, the inside of the vacuum device 2 can be reduced to atmospheric pressure or less by evacuating the inside of the vacuum device 2.

  In the above-described steps (1-4), (2-3), and (3-3), the photosensitive resin composition layer and the solar cell are supplied by supplying atmospheric pressure or pressurized fluid from the outside of the elastic body. The cells can be pressed and bonded together. Furthermore, the adhesiveness of the photosensitive resin composition layer and a photovoltaic cell can be improved more by heating with pressurization.

  When the photosensitive resin composition layer of the photosensitive film is set in the solar battery cell 10, the protective film present in some cases is removed and the lower base film B <b> 3 conveyed on the set table 1 by the conveying roll B <b> 1. The photosensitive film is set so that the support comes into contact with the substrate. The photovoltaic cell 10 is placed on the photosensitive resin composition layer of the photosensitive film, and the upper base film A3, the lower base film B3, the photosensitive film and the photovoltaic cell 10 are heated under pressure by the forward movement of the film moving chuck 3. It is drawn into the vacuum device 2 having the boards 2a and 2b. That is, the solar battery cell 10 in which the photosensitive resin composition layer is set in advance in the vacuum device 2 can be introduced. At this time, the surface shape of the photosensitive resin composition layer after removal of the protective film is not particularly limited.

  In addition, when mounting the photovoltaic cell 10 on the photosensitive resin composition layer, either the light-receiving surface 11a or the back surface 11b may be sufficient as the surface where the photovoltaic cell 10 contact | connects the photosensitive resin composition layer. Moreover, you may set the photosensitive resin composition layer on both surfaces of the light-receiving surface 11a or the back surface 11b of the photovoltaic cell 10. FIG. When the photosensitive resin composition layer is set on both surfaces of the solar battery cell 10, mechanical deterioration of the solar battery cell 10 can be further prevented.

  Moreover, when setting a photosensitive film in the photovoltaic cell 10, the photovoltaic cell 10 is arrange | positioned on the lower base film B3, and the photosensitive property of a photosensitive film on the photovoltaic cell 10 is moved, moving the lower base film B3. The resin composition layer may be set to introduce the solar battery cell into the vacuum device 2. That is, the solar battery cell 10 can be introduced while setting the photosensitive resin composition layer in the vacuum device 2. First, the photosensitive resin composition layer is disposed on the lower base film B3, and the solar battery cell 10 is placed on the photosensitive resin composition layer while the lower base film B3 is moved and introduced into the vacuum device 2. May be set.

  Moreover, the photosensitive resin composition layer is previously arranged on the upper base film A3 at a predetermined interval, and the solar cells 10 are arranged on the lower base film B3 at the same interval as the photosensitive resin composition layer. Then, the upper base film A3 and the lower base film B3 are respectively introduced into the vacuum apparatus 2, and the photosensitive resin composition layer and the solar battery cell 10 are brought into contact with each other in the apparatus 2 to thereby form the photosensitive resin composition layer. You may set to a photovoltaic cell. That is, the photosensitive resin composition layer is set in the solar battery cell 10 introduced into the vacuum device 2. In this case, the photosensitive resin composition layer may be disposed on either the upper base film A3 or the lower base film B3, or may be disposed on both. In addition, when the photosensitive resin composition layer is arrange | positioned in both upper base film A3 and lower base film B3, the photovoltaic cell 10 is set on any one photosensitive resin composition layer.

  Next, the lower heating platen 2a is raised, the heating plates 2a and 2b are sealed, and the inside of the vacuum device 2 is evacuated to an atmospheric pressure or lower, whereby the inside (housing portion) can be brought into a vacuum state. The evacuation is performed after the steps (1-2), (2-1), and (3-1). The evacuation at this time is more preferably less than atmospheric pressure, and further preferably a vacuum degree of 20 hPa. The evacuation time is preferably 5 to 60 seconds, more preferably 10 to 30 seconds, and still more preferably 15 to 20 seconds. If the evacuation time is less than 5 seconds, the inside of the heating plate (accommodating portion) does not reach a sufficient vacuum state, and there is a tendency that air voids are mixed when a film or the like is bonded, and the evacuation time is 60 If it exceeds 2 seconds, it will be left in the hot plate for a long time, so that the photosensitive film and the solar battery cells are partially stuck together and air voids tend to be mixed. The pressure is preferably 0.1 to 1.0 MPa, more preferably 0.2 to 0.7 MPa, and still more preferably 0.3 to 0.6 MPa. If the pressure is less than 0.1 MPa, there is a tendency to cause problems such as insufficient adhesion, and if the pressure exceeds 1.0 MPa, the solar battery cell may be damaged.

  FIG. 3 is a schematic cross-sectional view (a schematic cross-sectional view in a hot platen (example of solar cell back surface bonding)) showing a state where solar cells are introduced into a vacuum apparatus. In FIG. 3, the photosensitive resin composition layer 7 and the solar battery cell 10 are disposed between the upper and lower transport base films A3 and B3. In addition, although the photosensitive resin composition layer 7 is formed on the support body of the said photosensitive film, illustration of a support body is abbreviate | omitted.

  When the predetermined evacuation time ends, compressed air is supplied to the diaphragm, and the diaphragm expands and is pressed against the lower base film B3, the photosensitive film 7, the solar battery cell 10, and the upper base film A3 in this order. The pressurization time at this time can be set, and it is preferably 10 to 300 seconds, more preferably 20 to 90 seconds, and still more preferably 30 to 60 seconds. If the pressurization time is less than 10 seconds, there is a tendency to cause problems such as insufficient adhesion, and if the pressurization time exceeds 300 seconds, the solar cell 10 tends to be deformed.

  Here, a part of the diaphragm is formed of an elastic body, and when an atmospheric pressure or a pressurized fluid is supplied to the inside of the diaphragm from the outside, the diaphragm expands. And a photosensitive film and a photovoltaic cell are pressurized mutually with the pressure mentioned above. In addition, as for the diaphragm, the part used for pressurization should just be comprised with the elastic body. Examples of the elastic body include rubber.

  The solar cell 10 and the photosensitive film are heated and bonded by the heaters in the hot plates 2a and 2b. That is, the solar battery cell 10 and the photosensitive resin composition layer 7 of the photosensitive film are heated and adhered by the heater while being pressurized by the diaphragm. At this time, the temperature in the upper and lower panels 2a and 2b can be set, preferably 50 to 150 ° C, more preferably 60 to 130 ° C, and still more preferably 70 to 110 ° C. If the temperature in the upper and lower plates 2a and 2b is less than 50 ° C., there is a tendency to cause problems such as insufficient adhesion. If the temperature in the upper and lower plates 2a and 2b exceeds 150 ° C., depending on the pressurization time, the photosensitive film There is a tendency that a low boiling point compound or the like contained in the photosensitive resin composition layer 7 volatilizes.

  When the predetermined pressurization time ends, the diaphragm is depressurized and the inside returns to the atmospheric state. Thereafter, the lower heating platen 2a is lowered to be in a state where it can be taken out, and the solar battery cell to which the photosensitive resin composition layer of the photosensitive film is bonded can be taken out by transporting the transport base films A3 and B3.

  As shown in FIG. 2, the solar battery cell 10 has electrodes 13 and 15 such as silver and aluminum formed on the light receiving surface 11 a and the back surface 11 b. Therefore, in order to expose and take out the electrodes 13 and 15, as shown in FIG. 3, as shown in FIG. 3, the electrode corresponding portions of the photosensitive resin composition layer 7 are preliminarily processed by using a cutter, a punch, etc. By performing the processing, a hole (processed portion) 8 or the like is provided as shown in FIG. And when bonding the photosensitive resin composition layer 7 to the photovoltaic cell 10, this processed part 8 is correctly aligned and bonded to the electrode (electrode outlet) 15.

  Thereafter, the entire surface is irradiated with an actinic ray for exposure, and the base film (support) present in some cases is removed, whereby the electrode can be easily taken out. The electrode thus exposed is used when manufacturing a solar cell module described later. In addition, the photosensitive resin composition layer hardens | cures by exposure of actinic light, and the layer of the hardened photosensitive resin composition is provided on the light-receiving surface and / or back surface of a photovoltaic cell.

  Further, as another method for exposing the electrodes 13 and 15, after the photosensitive resin composition layer is bonded to the solar battery cell, a mask is used so that the electrode take-out portion can be removed, and actinic rays are exposed in an image shape. To do. After removing the base film (support) present in some cases, the electrode can be taken out by dissolving and removing unnecessary portions of the photosensitive resin composition layer with a developer.

  As the light source of the actinic light, a known light source, for example, a light source that effectively emits ultraviolet light, visible light, or the like, such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, or a xenon lamp is used.

  As the developer, a so-called semi-aqueous developer composed of an alkaline substance and one or more organic solvents is used. Examples of the alkaline substance include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and ammonium hydroxide, carbonates such as sodium carbonate and potassium carbonate, phosphates such as trisodium phosphate, and borax. Borate, sodium metasilicate, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 1,3- Examples include organic amines such as diaminopropanol-2 and morpholine, and other commonly used alkali substances, and these are used alone or in combination of two or more. It is desirable to maintain the pH of the developer as small as possible within a limit where the resist can be sufficiently developed. The pH is preferably 8 to 12, and more preferably 9 to 10.

  Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, and the like. Or in combination of two or more. The concentration of the organic solvent is usually in the range of 2 to 50% by volume. The temperature can be adjusted according to the developability. A small amount of a surface active agent and an antifoaming agent may be mixed in the developer. Development can be performed by immersing the substrate in the developer or spraying the developer.

  Moreover, alkali development and solvent development can also be selected according to the development type of the photosensitive resin composition layer.

  Thus, the photosensitive resin composition layer of the solar battery cell 10 to which the photosensitive resin composition layer is bonded is cured, and the layer of the photosensitive resin composition is provided. As described above, the method for curing the photosensitive resin composition layer includes a method for curing the photosensitive resin composition layer by irradiation with actinic rays. Further, such irradiation with actinic rays is performed in an image form, and unnecessary portions of the photosensitive resin composition layer are removed with a developer, whereby the electrodes of the solar battery cell 10 can be easily exposed and used. As a result, the productivity of the solar cell module can be further improved.

  In the reinforcing method, the layer of the photosensitive resin composition is provided on the light receiving surface 11a and / or the back surface 11b of the solar battery cell 10, and the layer of the photosensitive resin composition is a layer of the photosensitive resin composition. It is preferable that the light receiving surface electrode 11a or the back surface electrode 11b provided on the surface provided with a thickness not less than the thickness of the solar battery cell 10. Moreover, when providing the layer of the said photosensitive resin composition on the said light-receiving surface 11a and the back surface 11b, the thickness of the layer of the photosensitive resin composition on the said light-receiving surface 11a is the photosensitivity on the said back surface 11b. The thickness of the layer of the conductive resin composition is preferably provided so as to be within a range of ± 10%. Adjustment of the thickness of the photosensitive resin composition layer can be performed by adjusting the thickness of the photosensitive resin composition layer to be used.

  Moreover, when providing the layer of the said photosensitive resin composition on the said back surface 11b, it is preferable to provide the layer of the said photosensitive resin composition so that a part of said back surface electrode 15 may be exposed. Further, when the photosensitive resin composition layer is provided on the light receiving surface 11a, the photosensitive resin composition layer is provided as necessary so that a part of the light receiving surface electrode 13 is exposed. It is preferable. In addition, the electrodes 13 and 15 should just be exposed so that it can utilize, when manufacturing a solar cell module. In order to provide the photosensitive resin composition layer so that a part of the electrodes 13 and 15 is exposed, specifically, the photosensitive resin composition that has been subjected to processing such as outer shape processing and window opening processing as described above. The layer may be used, or the photosensitive resin composition layer may be bonded to the solar battery cell 10 and then exposed to actinic rays in an image form.

  A reinforced solar battery cell can be obtained by the method for reinforcing a solar battery cell described above. The manufacturing method of the reinforced solar battery cell is, for example, on the light receiving surface 11a and / or the back surface 11b of the solar battery cell 10 provided with the light receiving surface electrode 13 and the back electrode 15 in the same manner as the above-described solar cell reinforcing method. The sheet-like photosensitive resin composition (photosensitive resin composition layer) is laminated, and the sheet-like photosensitive resin composition is cured.

  4-6 is a figure which shows one Embodiment of the reinforced photovoltaic cell, respectively, FIG. 4 is a perspective view, FIG. 5 (a) is a top view, FIG.5 (b) is a bottom view, FIG. It is II sectional drawing of 5 (a) and (b). In the reinforced solar battery cell 20 shown in these drawings, a layer 21 of a photosensitive resin composition is provided on the light receiving surface and the back surface of the solar battery cell. The layer 21 of the photosensitive resin composition is processed so that at least a part of the elongated light-receiving surface electrode 13 and the hemispherical back surface electrode 15 is exposed.

  The reinforced solar battery cell 20 of the present embodiment has sufficient mechanical strength because the cured photosensitive resin composition layer 21 is provided on the light receiving surface and the back surface of the solar battery cell, Mechanical deterioration such as breakage hardly occurs. Accordingly, even when a plurality of cells are connected and sealed to form a module, the solar battery cell is hardly damaged, and the productivity of the solar battery module can be improved.

  The photosensitive resin composition layer 21 (particularly, the photosensitive resin composition layer provided on the light receiving surface) preferably has a light transmittance of 85% or more in the visible light region, and 90% or more. More preferably, it is 95% or more. When the layer of the photosensitive resin composition satisfies such a condition, the solar battery cell can sufficiently absorb sunlight, and the energy efficiency of the solar battery cell can be maintained at a high level. In addition, when the light transmittance is lower than 85%, there is a tendency to cause a problem that the energy efficiency of sunlight is lowered.

  FIG. 7 is an explanatory diagram showing a state in which a plurality of reinforced solar cells are connected in the manufacturing process of the solar cell module. In FIG. 7, each reinforced solar battery cell 20 is arranged such that the light receiving surface electrode 13 and the back surface electrode 15 are electrically connected by a conducting wire (aluminum or the like) 30.

  The reinforced solar cells thus electrically connected are further modularized using a back film, glass, and sealing resin. In general, in the case of a residential power solar cell, white plate tempered glass is used for glass, ethylene vinyl acetate (EVA) is used for sealing resin, and tedla film is used for the back film.

  The photosensitive resin composition layer in the present embodiment comprises (A) a polymer binder (preferably a vinyl polymerization polymer binder having an acid value of 10 to 46 mgKOH / g), and (B) at least one ethylene in the molecule. A photosensitive resin composition containing, as essential components, a photopolymerizable compound having a polymerizable unsaturated double bond and (C) a photopolymerization initiator (preferably a photopolymerization initiator that generates free radicals by actinic rays). preferable.

  The (A) polymer binder is obtained, for example, by copolymerizing a vinyl monomer having an acidic polar group such as (meth) acrylic acid or p-vinylbenzoic acid with other various vinyl monomers. Can do. Examples of other various vinyl monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene, benzyl (meth) acrylate, 2 -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2, 3 -Dibromopropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, acrylamide, (meth) acrylonitrile, etc. are mentioned, These are used individually or in combination of 2 or more types.

  When development is not required, it may be obtained as a copolymer of vinyl monomers having no acidic polar group. For example, Evaflex (registered trademark) (Mitsui, a copolymer of ethylene and vinyl acetate)・ Product name) manufactured by DuPont Polychemical Co., Ltd.

  The weight average molecular weight of the (A) polymer binder is preferably 20,000 to 200,000. If it is less than 20,000, the flexibility of the resist tends to be low and resist chipping tends to occur. If it exceeds 200,000, the developability tends to decrease.

As the photopolymerizable compound having at least one ethylenically unsaturated double bond in the molecule (B), for example,
(1) Diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, hexapropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,6-hexane Diol (meth) acrylate, dipentaerythritol penta (meth) acrylate, (meth) acrylate of polyhydric alcohols such as trimethylolpropane tri (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate,
(2) 2,2-bis [4- (meth) acryloxypolyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloxypolyethoxypolypropoxyphenyl] propane, bisphenol A, epichlorohydrin type epoxy Low molecular weight unsaturated polyesters such as epoxy (meth) acrylates such as (meth) acrylic acid adducts of resin, 1: 2: 2 molar ratio condensates of phthalic anhydride-neopentyl glycol- (meth) acrylic acid, etc. (Meth) acrylate having a benzene ring in the molecule,
(3) an adduct of trimethylolpropane triglycidyl ether with (meth) acrylic acid,
(4) A urethane (meth) acrylate compound obtained by reaction of trimethylhexamethylene diisocyanate with a (meth) acrylic acid monoester of a dihydric alcohol can be used.

  Examples of the (C) photopolymerization initiator include, for example, 1-hydroxy-cyclohexyl-phenyl-ketone [IRGACURE184 (manufactured by Ciba Specialty Chemicals Co., Ltd., product name)] which is excellent in compatibility and low yellowing property, benzophenone, benzophenones such as p, p-dimethylaminobenzophenone, p, p-diethylaminobenzophenone, p, p-dichlorobenzophenone, mixtures thereof, anthraquinones such as 2-ethylanthraquinone and t-butylanthraquinone, 2-chloro Examples include thioxanthone, benzoin isopropyl ether, benzoin ethyl ether, benzyl, 2,4,5-triarylimidazole dimer, and the like. These may be used alone or in combination of two or more. As the photopolymerization initiator, among the materials described above, those that do not easily absorb sunlight are preferable, and materials that are low yellowing are more preferable. By using such a material, the light transmittance after curing of the photosensitive resin composition can be adjusted to a range sufficient to be used for reinforcing the solar battery cell.

  In the photosensitive resin composition in the present embodiment, the total amount of the component (A) and the component (B) is 100 parts by weight within the range of 40 to 80 parts by weight of the component (A) and 20 to 60 parts by weight of the component (B). It is preferable to use 0.1 to 10 parts by weight of component (C) with respect to 100 parts by weight. When the amount of component (A) used exceeds 80 parts by weight, the sensitivity tends to decrease, and when it is less than 40 parts by weight, the handleability tends to decrease due to the stickiness of the photosensitive layer. Even if the amount of component (C) used exceeds 10 parts by weight, there is a tendency that there is no particular advantage, and when it is less than 0.1 parts by weight, the sensitivity tends to decrease.

  Moreover, in the photosensitive resin composition in this embodiment, each component mentioned above is suitably selected so that the light transmittance after hardening satisfy | fills the conditions mentioned above.

  In addition, dye, a plasticizer, a pigment, a flame retardant, a stabilizer, an adhesiveness imparting agent, etc. can also be added to the photosensitive resin composition used for this embodiment as needed.

  The photosensitive resin composition is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether or a mixed solvent thereof as necessary. And it can apply | coat as a solution about 25 to 70 weight% of solid content, and can be set as the photosensitive resin composition layer.

  The photosensitive resin composition layer of the present embodiment can be produced by, for example, forming a sheet shape by applying and drying a solution of the photosensitive resin composition on a base film (support). Examples of the base film (support) used here include polymer films such as polyethylene terephthalate, polypropylene, polyethylene, and polyester. A similar polymer film can be used as the protective film used in some cases. The thickness of these polymer films is preferably 1 to 100 μm.

  The application can be performed by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater. Moreover, drying can be performed at 70-150 degreeC and about 5 to 30 minutes. Further, the amount of the remaining organic solvent in the photosensitive resin composition layer is preferably 2% by weight or less from the viewpoint of preventing the organic solvent from diffusing in the subsequent step.

  The photosensitive film is stored, for example, as it is or by further laminating a protective film on the other surface of the photosensitive resin composition layer and winding it around a cylindrical core. In addition, it is preferable to wind up so that a support body may become the 1st outer side at this time. An end face separator is preferably installed on the end face of the roll-shaped photosensitive film roll from the viewpoint of end face protection, and a moisture-proof end face separator is preferably installed from the viewpoint of edge fusion resistance. Moreover, as a packing method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. In the examples and comparative examples, “part” means part by weight, and “%” means% by weight.

  The materials shown in Table 1 were blended to obtain a photosensitive resin composition solution.

  Next, the obtained photosensitive resin composition solution was uniformly applied onto a 24 μm-thick polyethylene terephthalate film (trade name G2-19, manufactured by Teijin Ltd.), and 10 times with a hot air convection dryer at 100 ° C. After drying for a minute, the film is protected with a protective film made of polyethylene (tensile strength in the film longitudinal direction: 16 Mpa, tensile strength in the film width direction: 12 Mpa, product name: NF-15, manufactured by Tamapoly Co., Ltd.). Obtained. The film thickness after drying of the photosensitive resin composition layer was 50 μm. Table 2 shows the results of an experiment for bonding to the polycrystalline silicon solar battery cell using the obtained photosensitive film. In addition, bonding of Examples 1-3 was performed as follows using the apparatus of the structure similar to the bonding apparatus shown by FIG. First, a solar battery cell in which a photosensitive resin composition layer was set was introduced into a vacuum device at a predetermined temperature. Next, the inside of the vacuum device was evacuated for a predetermined time, and the photosensitive resin composition layer and the solar battery cell were pressurized with a diaphragm in the vacuum device for a predetermined time. And the photovoltaic cell with which the photosensitive resin composition layer was bonded together was taken out from the vacuum apparatus. Table 2 also shows the conditions at the time of bonding in Examples 1 to 3. In Reference Example 1, the photosensitive resin composition layer was bonded to the solar battery cell using an atmospheric laminator in the apparatus.

* 1 Equipment: HLM-1500 Hitachi AIC Co., Ltd.
Laminating speed: 1.0 m / min, roll temperature: 110 ° C.,
Pressure: 0.4 Mpa.
* 2 ○: No peeling, ×: There is peeling.

  As can be seen from the results shown in Table 2, the photosensitive resin composition layer is bonded without damaging the solar battery cells by using an apparatus having the same configuration as the bonding apparatus shown in FIG. I was able to.

  Next, the photosensitive resin composition layer of the solar battery cell on which the photosensitive resin composition layer was laminated was irradiated with actinic rays to cure the photosensitive resin composition layer. Thus, the layer of the photosensitive resin composition was provided on the solar battery cell, and the reinforced solar battery cell was obtained.

  Next, using a UV spectrometer (Hitachi spectrophotometer U-3310 (Hitachi)), the light transmittance in the wavelength region of 300 to 900 nm after 60 minutes after exposure of the photosensitive resin composition layer was measured. The sample for light transmittance measurement was produced as follows. First, the photosensitive resin composition layer of the photosensitive film was laminated on a glass substrate at a speed of 1.0 m / min using a 110 ° C. heat roll while peeling off the protective film. That is, it has a three-layer structure of a glass substrate, a photosensitive resin composition layer, and a polyethylene terephthalate film. Next, using a large UV irradiation machine (manufactured by Oak Co., Ltd.) QRM-2317-F-00 having a high pressure mercury lamp lamp from the polyethylene terephthalate film side, the photosensitive resin composition layer is irradiated with ultraviolet rays, and this is irradiated with light. A sample for measuring transmittance was used. And on the measurement side of the UV spectrometer, a sample for measuring light transmittance from which a polyethylene terephthalate film has been peeled, that is, a sample made of a glass substrate and a layer of a cured photosensitive resin composition, and a glass substrate on the reference side, Continuous measurement was performed up to 300 to 900 μm. The results are shown in FIG. FIG. 8 is a graph showing the measurement results of the light transmittance of the layer of the cured photosensitive resin composition. As can be seen from the results shown in FIG. 8, it was confirmed that the layer of the photosensitive resin composition had a light transmittance of 85% or more in the visible light region. Moreover, the layer of the photosensitive resin composition has a light transmittance of 90% or more with respect to light having a wavelength of 400 to 900 nm, and it was confirmed that the layer is suitable for reinforcing the solar battery cell.

It is a schematic diagram which shows an example of the bonding apparatus used for the reinforcement method of a photovoltaic cell. It is a perspective view which shows an example of a photovoltaic cell. It is a schematic cross section which shows a mode that the photovoltaic cell was introduce | transduced in the vacuum apparatus. It is a perspective view showing one embodiment of a reinforced solar cell. Fig.5 (a) is a top view of the reinforced solar cell shown in FIG. 4, and FIG.5 (b) is a bottom view of the reinforced solar cell shown in FIG. It is sectional drawing of the reinforced photovoltaic cell shown in FIG. It is explanatory drawing which shows a mode that the several reinforced solar cell was connected in the manufacturing process of a solar cell module. It is a graph which shows the measurement result of the light transmittance of the layer of the hardened photosensitive resin composition.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Solar cell, 11 ... Board | substrate, 11a ... Light-receiving surface, 11b ... Back surface, 13 ... Light-receiving surface electrode, 15 ... Back electrode, 20 ... Reinforced solar cell, 21 ... Layer of photosensitive resin composition.

Claims (10)

  A method for reinforcing a solar cell, comprising providing a layer of a photosensitive resin composition on a light receiving surface and / or a back surface of a solar cell including a light receiving surface electrode and a back electrode.   The photosensitive resin composition layer has a thickness not less than the thickness of the light-receiving surface electrode or the back electrode provided on the surface on which the photosensitive resin composition layer is provided and not more than the thickness of the solar battery cell. The method for reinforcing a solar cell according to claim 1, wherein the method is provided in the solar cell.   The photosensitive resin composition layer on the light-receiving surface and the back surface, the thickness of the photosensitive resin composition layer on the light-receiving surface is the thickness of the photosensitive resin composition layer on the back surface 3. The method for reinforcing a solar cell according to claim 1, wherein the solar cell is provided so as to have a thickness within a range of ± 10%.   The layer of the said photosensitive resin composition is provided on the said back surface so that a part of said back surface electrode may be exposed, The reinforcement of the photovoltaic cell as described in any one of Claims 1-3 characterized by the above-mentioned. Method.   5. The layer of the photosensitive resin composition is provided on the light receiving surface as necessary so that a part of the light receiving surface electrode is exposed. 6. Solar cell reinforcement method.   The method for reinforcing a solar cell according to claim 1, wherein the light transmittance of the layer of the photosensitive resin composition in the visible light region is 85% or more.   The photosensitive resin composition for laminating | stacking on the light-receiving surface and / or back surface of a photovoltaic cell provided with the light-receiving surface electrode and the back surface electrode, and reinforcing the said photovoltaic cell.   A sheet-like photosensitive resin composition comprising the photosensitive resin composition according to claim 7 formed into a sheet shape.   The sheet-shaped photosensitive resin composition according to claim 8 is laminated on the light-receiving surface and / or the back surface of a solar battery cell having a light-receiving surface electrode and a back-surface electrode, and the sheet-shaped photosensitive resin composition is cured. A method for producing a reinforced solar cell, characterized by comprising:   Use of the photosensitive resin composition for reinforce | strengthening the said photovoltaic cell laminated | stacked on the light-receiving surface and / or back surface of a photovoltaic cell provided with the light-receiving surface electrode and the back surface electrode.

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