JP2013211286A - Wiring board, solar cell module, and manufacturing method of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which achieves low costs and enables an aluminium foil to be easily joined to a joined member, and to provide a solar cell module and a manufacturing method of the wiring board.SOLUTION: Multiple fine particles 61, which may be inserted into an aluminium foil 3, an insulative adhesive layer 2, and an insulative resin layer 4, are dispersed between the aluminium foil 3 forming a wiring pattern and the insulative adhesive layer 2 and between the aluminium foil 3 and the insulative resin layer 4.

Description

  The present invention relates to a wiring board, a solar cell module, and a manufacturing method of the wiring board.

Conventionally, for example, it is known that a metal such as copper, gold, or silver is used for a wiring pattern of an electric circuit formed on a substrate. In recent years, it has been studied to replace a cheaper aluminum or aluminum alloy (hereinafter simply referred to as aluminum) thin film instead of these metals.
When the aluminum foil is left in the air, the surface is covered with an oxide film. When this oxide film is present, the adhesion between the aluminum foil and the adhesive or insulating material, which is a member to be joined to the aluminum foil, is deteriorated. For this reason, various techniques for improving the adhesion between the aluminum foil and the adhesive or insulating material have been studied. For example, a technique for removing an oxide film by treating the surface of an aluminum foil with a chemical solution is disclosed (for example, see Patent Document 1).

JP 2002-59293 A

  However, in the above-described prior art, after the surface of the aluminum foil is treated with a chemical solution, it is necessary to perform operations such as water washing, draining, and drying, and there is a problem that the removal operation of the oxide film is troublesome and costly. .

  Therefore, the present invention has been made in view of the above-described circumstances, and is a wiring board, a solar cell module, and a wiring board capable of easily joining an aluminum foil and a member to be joined at low cost. A manufacturing method is provided.

  In order to solve the above-described problems, a wiring board according to the present invention includes a sheet-like base material, an aluminum foil that forms a wiring pattern on one surface of the base material, and a member to be joined to the aluminum foil. The wiring board is characterized in that a plurality of fine particles that can be inserted between the aluminum foil and the member to be joined are dispersed.

  The wiring board according to the present invention is characterized in that the member to be joined is at least one of an insulating adhesive and an insulating resin.

  The wiring board according to the present invention is characterized in that the fine particles are metal particles mainly containing at least one of nickel and zinc.

  In the wiring board according to the present invention, the fine particles are formed such that the diameter of the circumscribed circle is larger than the value of the surface roughness of the aluminum foil and the value of the surface roughness of the bonded member. Features.

  The wiring board according to the present invention is characterized in that the hardness of the fine particles is set to be higher than the hardness of the aluminum foil.

  The solar cell module according to the present invention has a wiring board and a connection electrode for wiring, and the connection electrode is connected to the aluminum foil via at least one of solder and silver paste. A battery cell is provided.

  A method of manufacturing a wiring board according to the present invention includes a sheet-like base material, an aluminum foil that forms a wiring pattern on one surface of the base material, and a wiring board in which a member to be joined is joined to the aluminum foil. In the manufacturing method, on the surface of the aluminum foil, a fine particle spraying step for spraying a plurality of fine particles that can be inserted into the aluminum foil, and after the fine particle spraying step, the plurality of fine particles are pressed and inserted into the aluminum foil. A pressing step of embedding a part of the fine particles in the aluminum foil, and a bonding step of disposing a bonded member on the surface of the aluminum foil after the pressing step and bonding the bonded member and the aluminum foil. It is characterized by that.

  According to the present invention, a plurality of fine particles bite into the aluminum foil and the member to be joined, and the adhesion between the aluminum foil and the member to be joined can be improved. For this reason, an aluminum foil and a to-be-joined member can be joined easily at low cost.

It is a typical exploded sectional view showing a schematic structure of a solar cell module in an embodiment of the present invention. It is a typical top view showing a schematic structure of a wiring board in an embodiment of the present invention. It is the A section enlarged view of FIG.

(Solar cell module)
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic exploded sectional view showing a schematic configuration of a wiring board according to the present invention and a solar cell module as a semiconductor device, and FIG. 2 is a schematic plan view showing a schematic configuration of the wiring board. These are the A section enlarged views of FIG.
As shown in FIGS. 1 and 2, the solar cell module 50 includes a solar cell 20 in which a plurality of wiring connection electrodes 20 a are provided on the back surface 20 c side opposite to the light receiving surface 20 b that receives light for power generation. A wiring substrate 10 for wiring the solar cells 20, a sealing material 30 that is stacked on the wiring substrate 10 and the solar cells 20 to seal the solar cells 20, and a stack on the sealing material 30. The transparent substrate 40 is provided.

(Solar cell)
The solar cell 20 performs power generation by photoelectrically converting light incident from the light receiving surface 20b, and is an appropriate method as long as it is a so-called back contact type solar cell in which the connection electrode 20a is provided on the back surface 20c. Can be adopted. Although FIG. 1 is a schematic diagram, the illustration is simplified, but the number of connection electrodes 20a can be appropriately set to two or more as needed.
Moreover, as the planar view shape of the photovoltaic cell 20, as shown by a two-dot chain line in FIG. 2, for example, an appropriate shape such as a rectangular shape in plan view can be adopted. Although not shown in FIGS. 1 and 2, a plurality of solar cells 20 in the solar cell module 50 are arranged adjacent to each other with a gap along the surface direction of the wiring board 10. .

(Wiring board)
The wiring board 10 includes a back sheet 6, a base material 1, and an insulating adhesive layer 2 laminated in this order, and an aluminum foil 3 and an insulating resin layer that protects the aluminum foil 3 on the insulating adhesive layer 2. (Solder resist layer) 4 is laminated.

The back sheet 6 constitutes one outer surface in the stacking direction of the wiring substrate 10 to suppress moisture, oxygen, and the like from entering the wiring substrate 10 and the solar cell module 50. It is a sheet-like member. For this reason, the back sheet 6 has a barrier function as a shield material.
As a material of the back sheet 6, an appropriate resin material having excellent barrier properties against moisture and oxygen, an aluminum foil, or a composite laminated film of an aluminum foil and an appropriate resin can be used.

  The base material 1 is a member that supports the aluminum foil 3 via the insulating adhesive layer 2, and is composed of, for example, a flexible sheet-like member. Moreover, it is preferable that the base material 1 consists of a material excellent in electrical insulation. For example, the base material 1 can employ a resin material formed into a sheet or film.

As a material of the base material 1, for example, a resin material such as acrylic, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyimide, urethane, epoxy, melamine, styrene, or a resin material obtained by copolymerization thereof can be used. .
Moreover, the material of the base material 1 can also use the material which mixed the organic filler or the inorganic filler etc. as needed for control of heat insulation, elasticity, or an optical characteristic.

  Furthermore, the base material 1 can employ a laminated film in which a plurality of the above resin materials are laminated, or a composite laminated film in which a layer of the above resin material and a metal foil such as an aluminum foil are laminated. is there. In addition, for example, when the above-mentioned composite laminated film is used, the back sheet 6 is deleted when the base material 1 has the necessary strength and moisture or oxygen barrier properties as the outer surface of the solar cell module 50. And it is good also as a structure in which the base material 1 serves as the function of the back sheet | seat 6. FIG.

  The insulating adhesive layer 2 is a layered portion for fixing the aluminum foil 3 to the surface of the base material 1 and, for example, urethane, acrylic, epoxy, polyimide, olefin, which is a curable resin, or a copolymer thereof. It is formed by curing the cured curable adhesive. The kind of curable adhesive is not specifically limited, For example, a thermosetting adhesive, a UV curable adhesive, etc. can be employ | adopted suitably. Moreover, you may use the adhesive layer which is not a step hardening type as the insulating adhesive layer 2. FIG.

  The aluminum foil 3 forms a wiring pattern for wiring the solar cells 20. The aluminum foil 3 has an appropriate plan view shape depending on the arrangement of the connection electrodes 20 a of the solar cells 20, and the insulating adhesive layer 2 is interposed therebetween. The base material 1 is laminated and joined to the base material 1 integrally. As a material of the aluminum foil 3, it is desirable to use, for example, high-purity aluminum such as 1N30 material in order to ensure as good electrical conductivity as possible.

As a wiring pattern of the aluminum foil 3, for example, as shown in FIG. 2, four linear portions 3 a ₁ , 3 a ₂ , 3 a ₃ , 3 a ₄ (hereinafter, linear portions 3 a ₁ to 3) having a substantially constant line width. 3a ₄ ) may be described as a comb-like portion 3A arranged in a comb-like shape, and four linear portions 3b ₁ , 3b ₂ , 3b ₃ , 3b ₄ (which have a substantially constant line width). Hereinafter, the linear portions 3b _{1 to} 3b ₄ may be described as comb-like portions 3B arranged in a comb-tooth shape, and these comb-tooth-like portions 3A and 3B are mutually connected. An example of the pattern that penetrates into the gap between the shaped parts and is arranged in close proximity to each other can be given.

In this example, the comb-like portions 3A and 3B correspond to the positive electrode wiring and the negative electrode wiring of the power generation output, respectively. Further, above the comb-like portions 3A and 3B (on the side of the solar battery cell 20), as shown by a two-dot chain line in FIG. 2, the solar battery cell 20 is positioned so as to cover the comb-like portions 3A and 3B from above. Be placed. At such a connection position, the solar battery cell 20 includes a total of 24 connection electrodes 20a (two points in FIG. 2), three above each of the linear portions 3a _{1 to} 3a ₄ and 3b _{1 to} 3b ₄ . (See chain line).
In addition, the shape of the pattern of the aluminum foil 3 shown in FIG. 2 and the number and arrangement of the connection electrodes 20a of the solar battery cells 20 are merely examples, and are not limited thereto.

The insulating resin layer 4, the entire except for the portion where the aluminum foil 3 on insulative adhesive layer 2 is formed, and each linear portion 3a 1 _{to 3 A} 4 in each pattern of the aluminum foil _3, 3b ₁ ~ It is formed so as to cover the side edges of 3b _4. Thereby, the aluminum foil 3 is protected. The insulating resin layer 4 is formed by applying an insulating resin by a known method such as a screen printing method or a photolithography method.

Here, as shown in FIG. 3, between the linear portions _{3a 1 ~3a 4, 3b 1 ~3b} 4 insulating adhesive layer 2 and the aluminum foil 3, and the linear portions _3a 1 _~3a 4, 3b _A plurality of fine particles 61 are respectively dispersed between _{1 to} 3b ₄ and the insulating resin layer 4. Then, the plurality of fine particles 61 are embedded in the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4 in a state where they are bitten.

  The fine particles 61 are metal particles mainly composed of at least one of nickel (Ni) and zinc (Zn), and can be inserted into the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4. Thus, it has a shape having a plurality of protrusions. Nickel and zinc have close electronegativity with aluminum, and relatively long-term reliability is good even if they are physically bitten into the aluminum foil 3.

  The hardness of the fine particles 61 is set higher than any hardness of the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4. Since the hardness of aluminum (Al) is higher than the hardness of the adhesive or resin, the hardness higher than any of the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4 means that aluminum. Needless to say, it is higher than the hardness of the foil 3.

  Further, the fine particles 61 are formed such that the diameter E1 of the circumscribed circle S1 (see the two-dot chain line in FIG. 3) is larger than the surface roughness value of the aluminum foil 3. More desirably, when the fine particles 61 are formed so that the diameter E1 is larger than the value of the surface roughness of the aluminum foil 3, and smaller than the film thickness of the insulating adhesive layer 2 or the insulating resin layer 4. Good. For example, the diameter E1 of the circumscribed circle S1 of the fine particles 61 is set to about 1 to 20 μm.

Figure 1, back to FIG. 2, on the linear portion _3a of each pattern of the aluminum foil _{3 1 ~3a 4, 3b 1 ~3b} 4 is conductively connected member 7 is disposed opposable position to the connection electrodes 20a, The aluminum foil 3 and the connection electrode 20 a of the solar battery cell 20 are connected via the conductive connection material 7.
The conductive connecting material 7 is not particularly limited as long as electrical connection between the aluminum foil 3 and the connection electrode 20a is possible. Preferable examples of the conductive connecting material 7 include solder and silver paste. As the solder, a solder containing tin, silver, copper, bismuth, lead, a flux component, etc., or a solder for aluminum can be used.

As a silver paste, a paste containing silver particles can be used for a silicone-based cured resin, an epoxy-based cured resin, a urethane-based cured resin, an acrylic-based cured resin, etc. Solder melting method and silver paste curing method A well-known method can be used according to each material. For example, techniques such as hot air reflow, IR reflow, oven heating, hot plate heating, and vacuum pressure lamination can be used.

If the sealing material 30 can seal and insulate the photovoltaic cell 20, it can be comprised from an appropriate material. Examples of suitable materials for the sealing material 30 include an ethylene / vinyl acetate copolymer (EVA) film.
The translucent substrate 40 is a member that guides incident light to the light receiving surface 20 b of the solar battery cell 20 and forms an outer surface opposite to the back sheet 6 in the solar battery module 50. In this embodiment, the structure which adhere | attached the glass panel on the surface of the sealing material 30 is employ | adopted.

(Production method)
Next, a method for manufacturing the wiring substrate 10 and the solar cell module 50 will be described with reference to FIGS.
As shown in FIG. 1 to FIG. 3, first, an insulating adhesive layer 2 is formed on a substrate 1, and this insulating adhesive layer 2 is a line of each pattern of an aluminum foil 3 to be formed later. A plurality of fine particles 61 are sprayed at positions corresponding to the shape portions 3a _{1 to} 3a ₄ and 3b _{1 to} 3b ₄ (particulate spraying step).

Then, the plurality of fine particles 61 are pressed by laminating or the like (pressing step). Then, each fine particle 61 is inserted into the insulating adhesive layer 2 and bites in. At this time, it presses so that a part of each fine particle 61 may bite, and it will be in the state where a plurality of fine particles 61 protrude from the surface of insulating adhesive layer 2. Note that the pressing force by lamination or the like is set to, for example, about 1 × 10 ⁵ [N / m ² ] or more, preferably about 1 × 10 ⁶ [N / m ² ] or more. About 1 × 10 ⁵ [N / m ² ] is the optimum pressure for laminating the solar cell module. Further, by setting the pressure to about 1 × 10 ⁶ [N / m ² ] or more, the fine particles 61 can be firmly entrapped. it can.

  Subsequently, the aluminum foil 3 on which the wiring pattern is not formed is laminated and bonded onto the insulating adhesive layer 2. At this time, an oxide film layer 71 is formed on the surface of the aluminum foil 3 by being exposed to the air. However, a plurality of fine particles 61 bite into the aluminum foil 3 due to the pressing force of the laminate. Thereby, the insulating adhesive layer 2 and the aluminum foil 3 are adhered to each other.

  Here, the hardness of the fine particles 61 is set higher than the hardness of the aluminum foil 3, and the fine particles 61 have a diameter E1 of the circumscribed circle S1 (see a two-dot chain line in FIG. 3) of the surface roughness of the aluminum foil 3. It is formed to be larger than the value. For this reason, each fine particle 61 surely breaks through the oxide film layer 71, and the fine particle 61 surely bites into the aluminum foil 3.

Next, a resist corresponding to the wiring pattern is formed by patterning on the surface of the aluminum foil 3, and the aluminum foil 3 that is not covered with the resist is removed by etching by chemical etching. Form. The film thickness T1 of the aluminum foil 3 is set to about 50 μm, for example. Thereafter, the resist on the wiring pattern is removed to form the respective linear portions 3a _{1 to} 3a ₄ and 3b _{1 to} 3b ₄ .
Here, when chemical etching is performed, if an aluminum etching solution residue remains on the insulating adhesive layer 2, it causes electric migration, and therefore it is desirable to include a residue removal step.

Subsequently, the formed wiring pattern, i.e., the linear portions _3a 1 _{to 3 A} 4 of the aluminum foil _3, 3b 1 to ～3B _4, again spraying a plurality of particles 61 (particle spraying step).
Then, the plurality of fine particles 61 are pressed by laminating or the like (pressing step). Then, each fine particle 61 breaks through the oxide film layer 71, and the fine particle 61 bites into the aluminum foil 3. At this time, in the same manner as when a plurality of fine particles 61 are dispersed on the surface of the insulating adhesive layer 2 described above, pressing is performed so that a part of each fine particle 61 bites. Then, a plurality of fine particles 61 protrude from the surface of the aluminum foil 3. Note that the pressing force is also set to about 1 × 10 ⁵ [N / m ² ] or more, preferably about 1 × 10 ⁶ [N / m ² ] or more, as described above, by the lamination or the like here.

Thereafter, whole body except a portion where the aluminum foil 3 on insulative adhesive layer 2 is formed, and the side edges of each linear portion _{3a 1 ~3a 4, 3b 1 ~3b} 4 in each pattern of the aluminum foil 3 The insulating resin layer 4 is formed so as to cover it. Then, some of the plurality of fine particles 61 are embedded in the insulating resin layer 4 (bonding step). Thereby, the aluminum foil 3 and the insulating resin layer 4 are adhered.
In this way, the aluminum foil 3 for forming the wiring pattern is laminated on the insulating adhesive layer 2, and the wiring board 10 is manufactured.

Next, the conductive connecting material 7 is disposed on the wiring board 10. For example, when the conductive connecting material 7 is a solder, it is heated and melted on the aluminum foil 3 or the heat-melted solder is dropped on the aluminum foil 3.
Here, the wiring substrate 10 is provided with an insulating resin layer 4 that protects the aluminum foil 3. The insulating resin layer 4 not only protects the aluminum foil 3 but also conducts from the aluminum foil 3. It also functions as a protective wall that prevents the connecting material 7 from leaking out.
Normally, it is difficult to connect the aluminum foil 3 and the solder. However, since the fine particles 61 mainly composed of nickel or zinc exist on the aluminum foil 3, the connection with a normal solder or silver paste is possible.

Subsequently, the connection electrode 20a on the back surface of the solar battery cell 20 is placed on the conductive connection material 7 in a state where the conductive connection material 7 is dissolved, and then the conductive connection material 7 is cooled. Thereby, the wiring pattern of the aluminum foil 3 and the connection electrode 20 a of the solar battery cell 20 are fixed in a conductive state via the conductive connection material 7.
Next, the film-shaped sealing material 30 and the translucent substrate 40 are laminated and a laminated laminating process is performed, thereby sealing the solar battery cell 20 and bonding the translucent substrate 40. Thereby, the solar cell module 50 is manufactured.

Thus, in the embodiment described above, between the each linear portion _{3a 1 ~3a 4, 3b 1 ~3b} 4 insulating adhesive layer 2 and the aluminum foil 3, and the linear portions _3a 1 _~3a 4, _3b 1 ~ 3b ₄ and the insulating resin layer 4 are each dispersed with a plurality of fine particles 61, and the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4 are in a state where the plurality of fine particles 61 have engulfed. Since it is embedded, the adhesiveness between the insulating adhesive layer 2 and the aluminum foil 3 and between the aluminum foil 3 and the insulating resin layer 4 can be enhanced. For this reason, the aluminum foil 3 and the insulating adhesive layer 2 and the insulating resin layer 4 can be easily joined at low cost.

  The fine particles 61 are metal particles mainly composed of at least one of nickel and zinc, and the hardness thereof is set higher than the hardness of the aluminum foil 3. In addition to this, the fine particles 61 are formed so that the diameter E1 of the circumscribed circle S1 (see the two-dot chain line in FIG. 3) is larger than the value of the surface roughness of the aluminum foil 3. For this reason, each fine particle 61 can pierce the oxide film layer 71 reliably, and the fine particle 61 can be surely entrapped in the aluminum foil 3. Therefore, the adhesiveness between the insulating adhesive layer 2 and the aluminum foil 3 and between the aluminum foil 3 and the insulating resin layer 4 can be reliably increased.

  Furthermore, in order to improve the adhesiveness between the insulating adhesive layer 2 and the aluminum foil 3 and between the aluminum foil 3 and the insulating resin layer 4, the aluminum foil 3 does not need to be treated with a chemical solution, so that the solar cell module 50 is manufactured. Cost can be further reduced.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the example in which the solar cell module 50 is formed after the wiring substrate 10 is manufactured in advance has been described. However, when it is not necessary to manufacture the wiring substrate 10 alone, the wiring substrate 10 is used. A part of the manufacturing process may be performed simultaneously with other manufacturing processes of the solar cell module 50.

Further, in the embodiment described above, between the each linear portion _{3a 1 ~3a 4, 3b 1 ~3b} 4 insulating adhesive layer 2 and the aluminum foil 3, and the linear portions _3a 1 _~3a 4, _3b 1 ~ A case where a plurality of fine particles 61 are respectively scattered between 3b ₄ and the insulating resin layer 4 has been described. However, not limited to this, between the each linear portion _{3a 1 ~3a 4, 3b 1 ~3b} 4 , and the each linear portion _{3a 1 ~3a 4, 3b 1 ~3b} 4 and the insulating resin layer 4 A plurality of fine particles 61 may be dispersed only in at least one of the regions. Furthermore, it is not necessary to the linear portion _3a 1 _{~3a 4,} 3b 1 more particles 61 throughout the ～3B ₄ of aluminum foil 3 is sprayed, may be sprayed intermittently particles 61 in a predetermined position .

In the above-described embodiment, the case where the fine particles 61 are formed of a metal containing at least one of nickel and zinc as a main component has been described. However, the present invention is not limited to this, and various materials can be applied to the fine particles 61 as long as the fine particles 61 can be inserted into the insulating adhesive layer 2, the aluminum foil 3, and the insulating resin layer 4. is there.
For example, even when the fine particles 61 are made of aluminum, the surface of the aluminum foil 3 becomes rough by spraying a plurality of fine particles 61 on the aluminum foil 3, so that the aluminum foil 3 and the insulating adhesive It is possible to improve the adhesion with the layer 2 and the insulating resin layer 4.

1 Base material 2 Insulating adhesive layer (Insulating adhesive)
3 Aluminum foil 4 Insulating resin layer (insulating resin)
7 Conductive Connection Material 10 Wiring Board 20 Solar Cell 20a Connection Electrode 50 Solar Cell Module 61 Fine Particle

Claims (7)

A sheet-like substrate;
An aluminum foil that forms a wiring pattern on one surface of the substrate;
A wiring board in which a member to be joined is joined to the aluminum foil,
A wiring board characterized in that a plurality of fine particles that can be inserted between the aluminum foil and the member to be joined are dispersed.   The wiring board according to claim 1, wherein the member to be bonded is at least one of an insulating adhesive and an insulating resin.   The wiring substrate according to claim 1, wherein the fine particles are metal particles containing at least one of nickel and zinc as a main component.   The fine particles are formed so that the diameter of the circumscribed circle is larger than the value of the surface roughness of the aluminum foil and the value of the surface roughness of the bonded member. Item 4. The wiring board according to any one of Items 3 to 3.   The wiring board according to claim 1, wherein the hardness of the fine particles is set to be higher than the hardness of the aluminum foil. The wiring board according to any one of claims 1 to 5,
A solar battery comprising a connection electrode for wiring, and the connection electrode connected to the aluminum foil via at least one of solder and silver paste module. A sheet-like substrate;
An aluminum foil that forms a wiring pattern on one surface of the substrate;
A method of manufacturing a wiring board in which a member to be joined is joined to the aluminum foil,
On the surface of the aluminum foil, a fine particle spraying step of spraying a plurality of fine particles that can be inserted into the aluminum foil,
After the fine particle spraying step, pressing the plurality of fine particles and inserting into the aluminum foil, a pressing step of embedding a part of the fine particles in the aluminum foil,
A method for manufacturing a wiring board, comprising: a bonding step of disposing a member to be bonded on the surface of the aluminum foil after the pressing step, and bonding the member to be bonded and the aluminum foil.

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