JP5889738B2 - Solar cell module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell module and a manufacturing method thereof.

  Solar cells are expected as new energy sources because they directly convert clean and inexhaustible sunlight into electricity.

The solar cell is used, for example, as a solar cell module in which a plurality of solar cells are connected via tab wires.
As the conventional tab wire, a type in which solder is applied to the surface of the copper wire has been used. And the electrode of the photovoltaic cell and the tab wire were connected via solder. However, since a high temperature is required for solder connection, the panel of the light receiving surface is cracked or warped, and a short circuit due to solder that has leaked out (leaked) from the tab wire has occurred, causing problems.

Therefore, adhesives such as conductive adhesives and insulating adhesives have been used as connection materials in place of solder. For example, a solar battery module in which a surface electrode of a solar battery cell and a tab wire are connected via a conductive adhesive has been proposed (see, for example, Patent Document 1).
However, in this proposed technique, the tab wire is not connected to the solar cell due to curing shrinkage of the conductive adhesive due to heating and pressing when connecting the surface electrode of the solar battery cell and the tab wire, and stress concentration on the conductive adhesive. There exists a problem that connection reliability falls, such as peeling from a battery cell. This problem becomes more prominent when the tab line is thinned to increase the light receiving area for the purpose of further increasing the photoelectric efficiency in recent years.

  Therefore, the present condition is that provision of a solar cell module excellent in connection reliability and a method for manufacturing the same is required.

JP 2010-258006 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a solar cell module excellent in connection reliability and a manufacturing method thereof.

Means for solving the problems are as follows. That is,
<1> A solar battery cell having an electrode, a tab wire, and a first adhesive,
The electrode of the solar battery cell and the tab wire are connected via the first adhesive,
At least in the connection region where the electrode of the solar battery cell and the tab wire are connected, the tab wire has two or more conductors, and the conductors are connected via a second adhesive. This is a solar cell module.
<2> The solar cell module according to <1>, wherein an average thickness in a connection direction of the conductor is 9 μm to 200 μm.
<3> The ratio (A / B) of the sum (A) of the average thickness (μm) in the connecting direction of each conductor in the tab line and the average width (μm) (B) of the tab line is 0.009 to The solar cell module according to any one of <1> to <2>, which is 0.250.
<4> The solar cell module according to any one of <1> to <3>, wherein the conductor contains one of copper and aluminum.
<5> The solar cell module according to any one of <1> to <4>, wherein the number of conductors in the tab line is 2 to 5.
<6> The solar cell module according to any one of <1> to <5>, which is any one of a crystalline solar cell module and a thin film solar cell module.
<7> The solar cell according to any one of <1> to <6>, wherein at least one of the first adhesive and the second adhesive is any one of a conductive adhesive and an insulating adhesive. It is a module.
<8> An arrangement step of arranging at least the first adhesive, the first conductor, the second adhesive, and the second conductor in this order on the electrode of the solar battery cell;
A covering step of covering the solar battery cell with a sealing resin, and further covering the sealing resin with either a moisture-proof backsheet or a glass plate;
A pressing step of pressing either the moisture-proof backsheet or the glass plate;
And a heating step of heating the heating stage on which the solar battery cell is placed.

  ADVANTAGE OF THE INVENTION According to this invention, the said various problems in the past can be solved, the said objective can be achieved, and the solar cell module which is excellent in connection reliability, and its manufacturing method can be provided.

FIG. 1 is a schematic top view showing an example of a thin film solar cell module. FIG. 2 is an exploded perspective view showing an example of a crystalline solar cell module. FIG. 3 is a schematic cross-sectional view showing an example of a crystalline solar cell module. FIG. 4 is a schematic cross-sectional view of an example of a tab line used in the present invention. FIG. 5 is a schematic top view of a crystalline solar cell model. FIG. 6 is a cross-sectional photograph of a thin film solar cell model (Example 2) in which tab wires are arranged.

(Solar cell module)
The solar cell module of the present invention has at least a solar cell, a tab wire, and a first adhesive, and, if necessary, other resins such as a sealing resin, a moisture-proof backsheet, and a glass plate. It has a member.
In the solar battery module, the electrode of the solar battery cell and the tab wire are connected via the first adhesive.

<Solar cell>
The solar battery cell is not particularly limited as long as it has electrodes, and can be appropriately selected according to the purpose.For example, the solar battery cell has at least a photoelectric conversion element as a photoelectric conversion unit, a finger electrode, and a bus bar electrode. Furthermore, it has other members as required.

  Examples of the solar battery cell include a thin film solar battery cell and a crystalline solar battery cell. Examples of the thin film solar cell include an amorphous silicon solar cell, a compound solar cell (CIS solar cell, CdS / CdTe solar cell), a dye-sensitized solar cell, and an organic thin film solar cell. And microcrystalline silicon solar cells (tandem solar cells). Examples of the crystalline solar battery cell include a single crystal silicon solar battery cell and a polycrystalline silicon solar battery cell.

  The solar battery cell may have a bus bar-less structure without a bus bar electrode.

  There is no restriction | limiting in particular as average thickness of the said photovoltaic cell, According to the objective, it can select suitably.

-Finger electrode-
The finger electrode is an electrode that collects electricity generated in the photoelectric conversion unit. The finger electrode is formed on the solar battery cell in a direction substantially orthogonal to the tab line.

  There is no restriction | limiting in particular as a material of the said finger electrode, Although it can select suitably according to the objective, For example, silver, gold | metal | money, copper, tin, nickel etc. are mentioned.

There is no restriction | limiting in particular as an average width | variety of the said finger electrode, Although it can select suitably according to the objective, 20 micrometers-200 micrometers are preferable, and 20 micrometers-100 micrometers are more preferable.
The average width can be obtained, for example, by measuring the width of the finger electrode at any 10 points of the finger electrode and averaging the measured values.

  There is no restriction | limiting in particular as a formation method of the said finger electrode, According to the objective, it can select suitably, For example, silver paste is printed on the said photoelectric conversion element so that the said finger electrode may become a desired pattern shape. Can be formed. Examples of the printing method include screen printing.

-Bus bar electrode-
The bus bar electrode is an electrode that further collects electricity collected by the finger electrodes and transmits the electricity to the tab wire.
In the solar cell having a bus barless structure, electricity is directly transmitted from the finger electrode to the tab wire.

  There is no restriction | limiting in particular as a material of the said bus-bar electrode, Although it can select suitably according to the objective, For example, silver, gold | metal | money, copper, tin, nickel etc. are mentioned.

There is no restriction | limiting in particular as an average width | variety of the said bus-bar electrode, Although it can select suitably according to the objective, 500 micrometers-5,000 micrometers are preferable, and 800 micrometers-2,000 micrometers are more preferable.
The average width can be obtained, for example, by measuring the width of the bus bar electrode at any 10 points of the bus bar electrode and averaging the measured values.

The method for forming the bus bar electrode is not particularly limited and may be appropriately selected depending on the purpose. For example, a silver paste is printed on the photoelectric conversion element so that the bus bar electrode has a desired pattern shape. Can be formed. Examples of the printing method include screen printing.
The bus bar electrode and the finger electrode may be formed simultaneously. For example, the bus bar electrode and the finger electrode are simultaneously formed by screen-printing a silver paste on the photoelectric conversion element using a printing plate having a pattern shape capable of forming a desired bus bar electrode and a desired finger electrode. can do.

<First adhesive>
There is no restriction | limiting in particular as said 1st adhesive agent, According to the objective, it can select suitably, For example, a conductive adhesive, an insulating adhesive agent, etc. are mentioned.

-Conductive adhesive-
The conductive adhesive is not particularly limited and may be appropriately selected depending on the purpose. For example, the conductive adhesive contains at least conductive particles, and preferably includes a film-forming resin, a curable resin, and a curing agent. A conductive adhesive containing other components as necessary is also included.

--Conductive particles--
The conductive particles are not particularly limited and may be appropriately selected depending on the purpose. For example, nickel particles, gold-coated nickel particles, resin particles with a resin core coated with Ni, and resin cores with Ni coated. Furthermore, resin particles whose outermost surface is coated with Au can be mentioned.

--- Film-forming resin--
There is no restriction | limiting in particular as said film formation resin, According to the objective, it can select suitably, For example, phenoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin Resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, phenoxy resin is particularly preferable.

--Curable resin--
There is no restriction | limiting in particular as said curable resin, According to the objective, it can select suitably, For example, an epoxy resin, an acrylate resin, etc. are mentioned.
In the said solar cell module, the said curable resin may be hardened | cured independently, and may be hardened with the hardening | curing agent mentioned later.

---- Epoxy resin ---
There is no restriction | limiting in particular as said epoxy resin, According to the objective, it can select suitably, For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, those modified epoxy resins, alicyclic type An epoxy resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

--- Acrylate resin ---
The acrylate resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol Propane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2, 2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) i Cyanurates, such as urethane acrylate, and the like. These may be used individually by 1 type and may use 2 or more types together.
Moreover, what made the said acrylate into the methacrylate is mentioned, These may be used individually by 1 type and may use 2 or more types together.

--Curing agent--
The curable resin is preferably used in combination with a curing agent. There is no restriction | limiting in particular as said hardening | curing agent, According to the objective, it can select suitably, For example, imidazole represented by 2-ethyl 4-methylimidazole; Lauroyl peroxide, butyl peroxide, benzyl peroxide, Organic peroxides such as dilauroyl peroxide, dibutyl peroxide, benzyl peroxide, peroxydicarbonate and benzoyl peroxide; anionic curing agents such as organic amines; cations such as sulfonium salts, onium salts and aluminum chelators System curing agents and the like.
Among these, combinations of epoxy resins and imidazoles, and combinations of acrylate resins and organic peroxides are particularly preferable.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a silane coupling agent, a filler, a softener, an accelerator, anti-aging agent, a coloring agent (pigment, dye) , Organic solvents, ion catcher agents and the like. There is no restriction | limiting in particular in the addition amount of the said other component, According to the objective, it can select suitably.

-Insulating adhesive-
The insulating adhesive is not particularly limited and may be appropriately selected depending on the purpose. For example, the insulating adhesive contains a film-forming resin, a curable resin, and a curing agent, and, if necessary, other Insulating adhesives containing these components may be mentioned.
The film-forming resin, the curable resin, the curing agent, and the other components in the insulating adhesive are not particularly limited and may be appropriately selected depending on the purpose. For example, the conductive adhesive Examples thereof include the film-forming resin, the curable resin, the curing agent, and the other components exemplified in the description of the agent.

  The first adhesive may be used in a liquid form or in a film form when the solar cell module is manufactured.

<Tab line>
The tab line includes two or more conductors at least in a connection region where the electrode of the solar battery cell and the tab line are connected. The conductors are connected via a second adhesive.

-Conductor-
The material of the conductor is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include copper, aluminum, iron, gold, silver, nickel, palladium, chromium, molybdenum, and alloys thereof. Can be mentioned.
The conductor preferably contains either copper or aluminum.

  There is no restriction | limiting in particular as a shape of the said conductor, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

  There is no restriction | limiting in particular as a structure of the said conductor, According to the objective, it can select suitably, A single layer structure may be sufficient and a laminated structure may be sufficient. Examples of the single layer structure include a single layer structure made of copper, aluminum, or the like. Examples of the laminated structure include a laminated structure having a base material made of copper, aluminum or the like and a plating layer. Examples of the material of the plating layer include gold, silver, tin, and solder.

There is no restriction | limiting in particular as average thickness of the connection direction of the said conductor, Although it can select suitably according to the objective, 9 micrometers-200 micrometers are preferable, and 9 micrometers-150 micrometers are more preferable. When the average thickness is less than 9 μm, the extraction efficiency of electricity generated by the solar battery cells may be lowered, and when it exceeds 200 μm, the connection reliability may be lowered. When the average thickness is within the more preferable range, it is advantageous in that connection reliability is more excellent.
The average thickness can be obtained, for example, by measuring the thickness in the connection direction of the conductor at any 10 points of the conductor and averaging the measured values.
It can be said that the connection direction is a direction orthogonal to the surface of the solar battery cell.

  There is no restriction | limiting in particular as the number of the said conductors in the said tab wire, Although it can select suitably according to the objective, 2-5 are preferable and 2-3 are more preferable. If the number exceeds 5, the tab wire may be misaligned in the pressing step when manufacturing the solar cell module, which may result in a decrease in connection reliability and a connection failure. When the number is within the more preferable range, it is advantageous in that connection reliability is more excellent.

The material of each of the two or more conductors in the tab line may be the same or different.
The average thickness in the connecting direction of the two or more conductors in the tab line may be the same or different.

Examples of the structure of the tab line include a structure arranged as follows.
(1) Conductor / second adhesive / conductor (2) Conductor / second adhesive / conductor / second adhesive / conductor (3) Conductor / second adhesive / conduct Body / second adhesive / conductor / second adhesive / conductor (4) conductor / second adhesive / conductor / second adhesive / conductor / second adhesive / conductive Body / second adhesive / conductor (5) conductor / second adhesive / conductor / second adhesive / conductor / second adhesive / conductor / second adhesive / conductive Body / second adhesive / conductor

  When an insulating adhesive is used for the first adhesive and the second adhesive, the electrical connection with the electrodes of the solar battery cell and the electrical connection between the conductors are facilitated. The conductor preferably has a protrusion on its surface. There is no restriction | limiting in particular as a material of the said protrusion, a shape, a magnitude | size, and a structure, According to the objective, it can select suitably. In addition, the thickness in the connection direction of the conductor when the conductor has a protrusion on the surface is a thickness of a portion excluding the protrusion.

-Second adhesive-
There is no restriction | limiting in particular as said 2nd adhesive agent, According to the objective, it can select suitably, For example, the adhesive agent similar to the said 1st adhesive agent etc. are mentioned. The component of the first adhesive and the component of the second adhesive may be the same or different.

  When the number of the conductors in the tab line is 3 or more, the second adhesive is used in two or more places. At this time, the components of the second adhesive in two or more places are the same. It may be different or different.

There is no restriction | limiting in particular as an average width | variety of the said tab line, Although it can select suitably according to the objective, 500 micrometers-10,000 micrometers are preferable, and 800 micrometers-4,000 micrometers are more preferable.
The average width can be obtained, for example, by measuring the width of the conductor in the tab line at any 10 points of the tab line and averaging the measured values. The width of the conductor is a direction orthogonal to the connection direction.

  There is no particular limitation on the ratio (A / B) of the sum (A) of the average thickness (μm) in the connecting direction of each conductor in the tab line and the average width (μm) (B) of the tab line. Depending on the purpose, it can be appropriately selected, but 0.009 to 0.250 is preferable, and 0.009 to 0.150 is more preferable. When the ratio (A / B) is less than 0.009, the extraction efficiency of electricity generated by the solar battery cell may be lowered, and when it exceeds 0.250, the connection reliability may be lowered. is there. When the ratio (A / B) is within the more preferable range, it is advantageous in that connection reliability is further improved.

<Resin for sealing>
The sealing resin is not particularly limited and may be appropriately selected depending on the purpose. For example, ethylene / vinyl acetate copolymer (EVA), ethylene / vinyl acetate / triallyl isocyanurate (EVAT), Examples include polyvinyl butyrate (PVB), polyisobutylene (PIB), silicone resin, polyurethane resin, and the like.

<Dampproof back sheet>
There is no restriction | limiting in particular as said moisture-proof backsheet, According to the objective, it can select suitably, For example, the laminated body of polyethylene terephthalate (PET), aluminum (Al), PET, Al, and polyethylene (PE) etc. Can be mentioned.

<Glass plate>
There is no restriction | limiting in particular as said glass plate, According to the objective, it can select suitably, For example, a soda-lime float glass plate etc. are mentioned.

  The solar cell module may be a thin film solar cell module using the thin film solar cell, or may be a crystalline solar cell module using the crystalline solar cell.

An example of the solar cell module of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic top view showing an example of a thin-film solar cell module 200. In the thin-film solar cell module 200 of FIG. 1, thin-film solar cells 32 made of thin-film photoelectric conversion elements are arranged in series on a substrate 38 in a planar direction. Then, the surface electrode (not shown) of the thin film solar cell 32c at one end and the surface electrode (not shown) of the thin film solar cell 32d at the other end are provided with a conductive adhesive layer (not shown). Thus, a tab wire 3 for power extraction is connected.

  FIG. 2 is an exploded perspective view showing an example of a crystalline solar cell module. The crystalline solar cell module 1 includes strings 4 in which a plurality of crystalline solar cells 2 are connected in series by tab wires 3 serving as interconnectors, and further includes a matrix 5 in which a plurality of strings 4 are arranged. In the crystalline solar cell module 1, the matrix 5 is sandwiched between the sealing resin sheets 6, and together with the front cover 7 provided on the light receiving surface side and the moisture-proof back sheet 8 provided on the back surface side. And laminated. Finally, the crystalline solar cell module 1 is formed by attaching a metal frame 9 such as aluminum around the periphery.

Moreover, as shown in FIG. 3, each crystalline solar cell 2X, 2Y, 2Z of the crystalline solar cell module has a crystalline photoelectric conversion element 10 made of a silicon substrate. The crystalline photoelectric conversion element 10 is provided with a bus bar electrode 11 serving as a surface electrode on the light receiving surface side and a finger electrode 12 serving as a collecting electrode formed in a direction substantially orthogonal to the bus bar electrode 11. The crystalline photoelectric conversion element 10 is provided with an Al back electrode 13 made of aluminum on the back side opposite to the light receiving surface.
Then, the bus bar electrode 11 on the surface of the solar battery cell 2 and the Al back electrode 13 of the adjacent solar battery cell 2 are electrically connected by the tab wire 3, thereby constituting the strings 4 connected in series. . The connection between the tab wire 3 and the bus bar electrode 11 and the connection between the tab wire 3 and the Al back electrode 13 are performed by, for example, the conductive adhesive film 17.

  FIG. 4 is a schematic cross-sectional view showing an example of a tab line. The tab wire 3 is a laminated body in which a first conductor 3a, a second adhesive 3b, and a second conductor 3c are laminated in this order. The second adhesive 3b is formed using, for example, a conductive adhesive film.

(Method for manufacturing solar cell module)
The manufacturing method of the solar cell module of the present invention includes at least a disposing step, a covering step, a pressing step, and a heating step, and further includes other steps as necessary.
The manufacturing method of the solar cell module of this invention can be used suitably for manufacture of the said solar cell module of this invention.

<Arrangement process>
As the arrangement step, at least a first adhesive, a first conductor, a second adhesive, and a second conductor are arranged in this order on the electrode of the solar battery cell. If there is, there is no restriction | limiting in particular, According to the objective, it can select suitably.
The first conductor, the second adhesive, and the second conductor form a tab line in the solar cell module of the present invention.

  Examples of the solar battery cell include the solar battery cell exemplified in the description of the solar battery module of the present invention.

Examples of the first adhesive and the second adhesive include the first adhesive and the second adhesive exemplified in the description of the solar cell module of the present invention.
There is no restriction | limiting in particular as average thickness in the connection direction of a said 1st adhesive agent and a said 2nd adhesive agent, Although it can select suitably according to the objective, 3 micrometers-100 micrometers are preferable, and 5 micrometers-50 micrometers are more. Preferably, 10 μm to 35 μm is more preferable.
The average thickness can be obtained, for example, by measuring the thickness in the connecting direction at any 10 points of the first adhesive and the second adhesive and averaging the measured values.

  Examples of the first conductor and the second conductor include the conductors exemplified in the description of the solar cell module of the present invention.

An example of the arrangement step will be described.
A film-like conductive adhesive (conductive adhesive film, first adhesive) slit to the same width as the bus bar electrode is placed on the bus bar electrode of the solar battery cell. Subsequently, a copper foil (first conductor) having the same width as that of the bus bar electrode is placed on the first adhesive. Subsequently, a film-like conductive adhesive (conductive adhesive film, second adhesive) slit to the same width as the bus bar electrode is placed on the first conductor. Subsequently, a copper foil (second conductor) having the same width as that of the bus bar electrode is placed on the second adhesive. An arrangement | positioning process can be performed by the above.

Another example of the arrangement step will be described.
First, a two-layer body in which a film-like conductive adhesive (adhesive) is placed on a copper foil (conductor) is prepared. The width of the two-layer body is set to the same width as the bus bar electrode of the solar battery cell.
Subsequently, the two-layer body (first two-layer body) is placed on the bus bar electrode of the solar battery cell so that the adhesive (first adhesive) and the bus bar electrode are in contact with each other. Further, another two-layer body (second two-layer body) is placed on the placed two-layer body (first two-layer body), and the first two-layer body conductor (first And the second two-layer adhesive (second adhesive) are in contact with each other. An arrangement | positioning process can be performed by the above.

Another example of the arrangement step will be described.
First, a four-layer body in which two two-layer bodies on which a film-like conductive adhesive (adhesive) is placed on a copper foil (conductor) is prepared. The width of the four-layer body is set to the same width as the bus bar electrode of the solar battery cell.
Subsequently, the four-layer body is placed on the bus bar electrode of the solar battery cell so that the adhesive (first adhesive) and the bus bar electrode are in contact with each other. An arrangement | positioning process can be performed by the above.

  After the arrangement step, the first conductor, the second conductor, and the electrode of the solar battery cell may be electrically connected or may not be electrically connected. .

<Coating process>
The covering step is not particularly limited as long as it is a step of covering the solar battery cell with a sealing resin and further covering the sealing resin with either a moisture-proof backsheet or a glass plate. Can be selected as appropriate.

  The solar cell module manufacturing method as described above is preferably performed using a reduced pressure laminator. The method of using the reduced pressure laminator can be performed with reference to the method described in JP 2010-283059 A, for example.

  The sealing resin, the moisture-proof backsheet, and the glass plate are not particularly limited and can be appropriately selected according to the purpose. For example, the examples exemplified in the description of the solar cell module of the present invention. Examples thereof include a sealing resin, the moisture-proof backsheet, and the glass plate.

<Pressing step and heating step>
The pressing step is not particularly limited as long as it is a step of pressing either the moisture-proof backsheet or the glass plate, and can be appropriately selected according to the purpose. The pressure to press and the time to press are arbitrary.

  The heating step is not particularly limited as long as it is a step of heating the heating stage on which the solar battery cell is placed, and can be appropriately selected according to the purpose. The sealing resin can be heated by heating the heating stage. Further, the first adhesive and the second adhesive can be heated.

  There is no restriction | limiting in particular as heating temperature in the said heating process, Although it can select suitably according to the objective, 50 to 250 degreeC is preferable and 100 to 200 degreeC is more preferable. When the heating temperature is less than 50 ° C., sealing may be insufficient, and when it exceeds 250 ° C., an organic resin contained in an adhesive, a sealing resin, or the like may be thermally decomposed. When the heating temperature is within the more preferable range, it is advantageous in terms of sealing reliability.

  There is no restriction | limiting in particular as the heating time in the said heating process, Although it can select suitably according to the objective, 1 second-1 hour are preferable, 5 seconds-30 minutes are more preferable, and 10 seconds-20 minutes are especially. preferable. If the heating time is less than 1 second, sealing may be insufficient. When the heating time is within the particularly preferable range, it is advantageous in terms of sealing reliability.

  There is no restriction | limiting in particular as an order which starts the said press process and the said heating process, According to the objective, it can select suitably.

  In the arrangement step, when the first conductor, the second conductor, and the electrode of the solar battery cell are not electrically connected, the pressing step and the heating step cause the first conductor, One conductor, the second conductor, and the electrode of the solar battery cell may be electrically connected.

By doing so, the solar cell module of the present invention is manufactured.
Further, for example, the solar cell module of the present invention can be manufactured by forming a matrix in which a plurality of strings in which a plurality of solar cells are directly connected are arranged and sealing the matrix.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Production of solar cell module model>
-Conductor-
A copper foil (average thickness 9 μm) slit to an average width of 2,000 μm was used as the conductor.

-Conductive adhesive film-
A conductive adhesive film (SP100 series, average thickness 25 μm, manufactured by Sony Chemical & Information Device Co., Ltd.) was prepared and used by slitting to an average width of 2,000 μm.

-Fabrication of thin-film solar cell module model-
A glass substrate (length 100 mm × width 100 mm × thickness 0.7 mm) having a silver electrode formed on the entire surface was prepared. This is a thin film solar cell model.

A conductive adhesive film (first adhesive), a conductor (first conductor), a conductive adhesive film (second adhesive), and a conductor on the electrode of the thin-film solar cell model (Second conductor) was disposed in this order, and then temporarily attached. The temporary bonding conditions were a heating temperature of 70 ° C., a pressure of 0.5 MPa, and 1 second, and a heating tool was used.
As described above, a thin film solar cell model with a tab line in which the first adhesive and the tab wire were laminated on the electrode of the thin film solar cell model was obtained. The tab wire is a laminated body in which a first conductor, a second adhesive, and a second conductor are laminated. Two laminates were arranged on the electrode of the thin-film solar cell model with an interval of 8.0 cm.

Subsequently, the obtained thin-film solar cell model with tab wires was covered with a sealing resin, and the sealing resin was further covered with a moisture-proof backsheet. As the sealing resin, an ethylene / vinyl acetate copolymer having a thickness of 500 μm was used. A PET film was used for the back sheet.
The sealing resin was sealed with a laminator. Specifically, vacuuming was performed at 100 ° C. for 5 minutes, followed by laminating at a press time of 5 minutes and 0.1 MPa, and then curing in an oven at 155 ° C. for 45 minutes.
As described above, a thin film solar cell module model was obtained.

<Evaluation>
The thin film solar cell module obtained above was subjected to the following evaluation. The results are shown in Table 1.

-Connection reliability-
The resistance value between two tab wires of the obtained thin film solar cell module model was measured.
Resistance values after initial, after TC200, and after TC400 were measured using a digital multimeter (manufactured by Yokogawa Electric Co., Ltd., digital multimeter 7555), and evaluated according to the following evaluation criteria.
The TC200 has a temperature increase from −40 ° C. to 85 ° C. (temperature increase rate 2 ° C./min), a hold at 85 ° C. for 35 minutes, and a temperature decrease from 85 ° C. to −40 ° C. (temperature decrease rate 2 ° C./min). ) And hold at -40 [deg.] C. for 35 minutes as one cycle, and a test for 200 cycles. The TC400 indicates a test in which the cycle is performed 400 times.
〔Evaluation criteria〕
◎: Less than 10 mΩ ○: 10 mΩ or more and less than 20 mΩ Δ: 20 mΩ or more and less than 100 mΩ ×: 100 mΩ or more

(Examples 2 to 8)
In Example 1, except that the material of the conductor, the average thickness of the conductor, and the average width of the tab line were respectively changed to the material of the conductor, the average thickness of the conductor, and the average width of the tab line shown in Table 1. In the same manner as in Example 1, a thin film solar cell module model was prepared and evaluated. The results are shown in Table 1.
In Example 7, the average width of the conductive adhesive film was 800 μm. In Example 8, the average width of the conductive adhesive film was 1,500 μm.
Here, the cross-sectional photograph of the thin film solar cell model (Example 2) in which the tab wires are arranged is shown in FIG. A tab wire formed by connecting the first conductor 3a and the second conductor 3c via the second adhesive 3b is disposed on the solar cell model 2a via the conductive adhesive film 17. Yes.

Example 9
In Example 1, except that a conductive adhesive film (third adhesive) and a conductor (third conductor) were further arranged in this order on the second conductor during temporary attachment. In the same manner as in Example 1, a thin film solar cell module model was prepared and evaluated. The results are shown in Table 1.

(Example 10)
As a crystalline solar cell model, a glass substrate on which finger electrodes 12 with an average width of 100 μm and bus bar electrodes 11 with an average width of 2,000 μm were formed as shown in FIG. Specifically, a pattern of finger electrodes 12 and bus bar electrodes 11 as shown in FIG. 5 is formed by screen printing and baking a silver paste on a glass substrate (length 125 mm × width 125 mm × thickness 0.7 mm). Crystalline solar cell model 2 ′ was obtained.
On the bus bar electrode of the obtained crystalline solar cell model, the conductive adhesive film (first adhesive) shown in Example 1 and the conductor (first conductor) shown in Example 1 were implemented. The conductive adhesive film (second adhesive) shown in Example 1 and the conductor (second conductor) shown in Example 1 were disposed in this order, and then temporarily attached. The temporary bonding conditions were a heating temperature of 70 ° C., a pressure of 0.5 MPa, and 1 second, and a heating tool was used.
In this way, a crystalline solar cell model with a tab line in which the first adhesive and the tab line were laminated on the bus bar electrode of the crystalline solar cell model was obtained. The tab wire is a laminated body in which a first conductor, a second adhesive, and a second conductor are laminated.
In Example 1, a crystalline solar cell module model was prepared and evaluated in the same manner as in Example 1, except that the tabbed crystalline solar cell model obtained above was used. The results are shown in Table 1.

(Examples 11 to 13)
In Example 1, the average thickness of the first conductor, the average thickness of the second conductor, and the average width of the tab line are the average thickness of the first conductor described in Table 2, and the second conductor A thin film solar cell module model was prepared and evaluated in the same manner as in Example 1 except that the average thickness and the average width of the tab line were changed. The results are shown in Table 2.

(Example 14)
In Example 4, a thin-film solar cell module model was prepared and evaluated in the same manner as in Example 4 except that the average thickness of the conductive adhesive film was changed to 10 μm. The results are shown in Table 2.

(Example 15)
In Example 4, a thin-film solar cell module model was produced and evaluated in the same manner as in Example 4 except that the average thickness of the conductive adhesive film was changed to 35 μm. The results are shown in Table 2.

(Comparative Example 1)
-Fabrication of soldered tab wire-
Copper foil having an average thickness of 400 μm was slit into an average width of 2 mm (2,000 μm).
The slit copper foil was plated with Sn (96.5 mass%) / Ag (3 mass%) / Cu (0.5 mass%) lead-free solder to obtain a soldered tab wire.

-Fabrication of thin-film solar cell model with tab wires-
The soldered tab wire obtained above was arranged on the electrode of the thin-film solar cell model prepared in Example 1 so that the electrode and the solder of the soldered tab wire were in contact with each other. Two soldered tab wires were arranged, and the interval between them was the same as in Example 1.
Then, using a soldering iron, it was heated at a heating temperature of 240 ° C. to obtain a thin film solar cell model with a tab wire.

-Fabrication of thin-film solar cell module model-
Subsequently, the obtained thin-film solar cell model with tab wires was covered with a sealing resin, and the sealing resin was further covered with a moisture-proof backsheet. As the sealing resin, an ethylene / vinyl acetate copolymer having a thickness of 500 μm was used. A PET film was used for the back sheet.
The sealing resin was sealed with a laminator. Specifically, vacuuming was performed at 100 ° C. for 5 minutes, followed by laminating at a press time of 5 minutes and 0.1 MPa, and then curing in an oven at 155 ° C. for 45 minutes.
As described above, a thin film solar cell module model was obtained.
The obtained thin film solar cell module model was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 2)
A thin-film solar cell module in the same manner as in Example 1, except that the average thickness of the first conductor was changed to 400 μm and the second adhesive and the second conductor were not used in Example 1. A model was created and evaluated. The results are shown in Table 2.

(Comparative Example 3)
In Comparative Example 1, a thin-film solar cell module was prepared and evaluated in the same manner as Comparative Example 1 except that the average thickness of the copper foil was changed to 200 μm. The results are shown in Table 2.

(Comparative Example 4)
In Comparative Example 2, a thin-film solar cell module was produced and evaluated in the same manner as in Comparative Example 2 except that the average thickness of the first conductor was changed to 200 μm. The results are shown in Table 2.

It has confirmed that the solar cell module produced in Examples 1-15 was excellent in connection reliability.
As the average thickness of the conductor, it was confirmed that 9 μm to 150 μm was very preferable since the conduction resistance was very excellent even after TC400 (see, for example, Examples 1 to 4 and Example 11). As the sum of the average thicknesses of the conductors in the tab wire, it was confirmed that 18 μm to 300 μm was very preferable since the conduction resistance was very excellent even after TC400 (for example, Examples 1 to 4 and Example 11). reference).
As the ratio (A / B) of the sum (A) of the average thickness (μm) of each conductor in the tab wire and the average width (μm) (B) of the tab wire, the conduction resistance is very excellent even after TC400. From the point, it was confirmed that 0.009 to 0.150 is very preferable (for example, see Examples 1 to 4, 8 to 9, and 11).
As the material of the conductor, it was confirmed that both copper and aluminum have excellent connection reliability (for example, see Examples 4 and 6).
As the type of the solar cell module, it was confirmed that the connection reliability was excellent in both the thin-film solar cell module and the crystalline solar cell module (for example, see Examples 4 and 10).
On the other hand, in Comparative Examples 1 and 2, the conduction resistance was very large in TC200 and TC400, and the connection reliability was not sufficient. Further, in Comparative Examples 3 and 4, the conduction resistance increased with TC400, and the connection reliability was not sufficient.

  Since the solar cell module of the present invention is excellent in connection reliability, it can be particularly suitably used for a solar cell module in which the tab line is thinned for increasing the light receiving area for the purpose of increasing the photoelectric efficiency.

DESCRIPTION OF SYMBOLS 1 Crystalline solar cell module 2 Crystalline solar cell 3 Tab wire 3a 1st conductor 3b 2nd adhesive agent 3c 2nd conductor 4 Strings 5 Matrix 6 Sheet 7 Surface cover 8 Back sheet 9 Metal frame 10 Crystal System photoelectric conversion element 11 Bus bar electrode 12 Finger electrode 13 Al back electrode 17 Conductive adhesive film 32 Thin film solar cell 32a Thin film solar cell model 38 Base material 200 Thin film solar cell module

Claims (8)

A solar cell having an electrode, a tab wire, and a first adhesive;
The electrode of the solar battery cell and the tab wire are connected via the first adhesive,
At least in the connection region where the electrode of the solar battery cell and the tab wire are connected, the tab wire has two or more conductors, and the conductors are connected via a second adhesive ,
The first adhesive is a conductive adhesive containing conductive particles,
The second adhesive is a conductive adhesive having an average thickness of 10 μm to 35 μm containing conductive particles,
The ratio (A / B) of the sum (A) of the average thickness (μm) in the connection direction of the conductors in the tab line to the average width (μm) (B) of the tab line is 0.009 to It is 0.250, The solar cell module characterized by the above-mentioned.   The solar cell module according to claim 1, wherein an average thickness in a connecting direction of the conductor is 9 μm to 200 μm. The ratio (A / B) of the total (A) of the average thickness (μm) in the connecting direction of each conductor in the tab line and the average width (μm) (B) of the tab line is 0.009 to 0.150. The solar cell module according to any one of claims 1 to 2.   The solar cell module according to any one of claims 1 to 3, wherein the conductor contains one of copper and aluminum.   The solar cell module according to any one of claims 1 to 4, wherein the number of conductors in the tab wire is 2 to 5.   The solar cell module according to any one of claims 1 to 5, which is either a crystalline solar cell module or a thin film solar cell module. The average thickness of a 1st adhesive agent is 10 micrometers-35 micrometers, The solar cell module in any one of Claim 1 to 6. A method for manufacturing a solar cell module according to any one of claims 1 to 7,
An arrangement step of arranging at least the first adhesive, the first conductor, the second adhesive, and the second conductor in this order on the electrode of the solar battery cell;
A covering step of covering the solar battery cell with a sealing resin, and further covering the sealing resin with either a moisture-proof backsheet or a glass plate;
A pressing step of pressing either the moisture-proof backsheet or the glass plate;
And a heating step of heating the heating stage on which the solar cells are placed. A method for manufacturing a solar cell module, comprising: