JP2018056145A - Photovoltaic module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic module having high degree-of-freedom in selection of a material of a sealing layer, and ensuring better generation efficiency.SOLUTION: A photovoltaic module 100 includes a heterojunction photovoltaic element 10, multiple first micro wirings 21 bonded and fixed to a first electrode 15 on one side of the photovoltaic element 10 by a first adhesive layer 22, and a first resin film 23 sandwiching the multiple first micro wirings 21 between one side of the photovoltaic element 10, and bonded to one side of the photovoltaic element 10 via the first adhesive layer 22. The photovoltaic module 100 further includes a translucent first protective layer 40, and a first sealing layer 30 filling between the first protective layer 40 and the first resin film 23. The first adhesive layer 22 is composed of a resin material containing a copolymer (e.g., ionomer) of ethylene and unsaturated carboxylic acid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photovoltaic module.

  As a kind of photovoltaic module, there is a type having a heterojunction photovoltaic element.

The heterojunction type photovoltaic device includes a first amorphous semiconductor film and a first conductive type second amorphous system on one surface side of a first conductive type (mainly n-type) crystalline semiconductor substrate. A semiconductor film, a first translucent electrode film, and a first electrode are provided in this order. Here, the first amorphous semiconductor film is an intrinsic amorphous semiconductor film, or the first conductivity type amorphous system having an impurity concentration lower than that of the second amorphous semiconductor film. It is a semiconductor film.
Further, the photovoltaic element has an intrinsic amorphous semiconductor film, a second conductive type (mainly p-type) amorphous semiconductor film, and a second light-transmitting electrode on the other surface side of the crystalline semiconductor substrate. The membrane and the second electrode are provided in this order.

The photovoltaic module is bonded to one surface of the photovoltaic element via the first adhesive layer and a plurality of first fine wirings bonded and fixed to the first electrode on one surface of the photovoltaic element by the first adhesive layer. And a first resin film sandwiching a plurality of first fine wirings between one surface of the photovoltaic device, a translucent substrate, and between the translucent substrate and the first resin film And a filled first sealing layer.
Further, the photovoltaic module includes a plurality of second fine wirings bonded and fixed to the second electrode on the other surface of the photovoltaic element by the second adhesive layer, and the other of the photovoltaic elements via the second adhesive layer. A second resin film bonded to the surface and sandwiching a plurality of second fine wirings between the other surface of the photovoltaic element, a back sheet or a second translucent substrate, and a back sheet or first And a second sealing layer filled between the translucent substrate 2 and the second resin film.

  Patent Document 1 describes an epoxy adhesive, an acrylic adhesive, a rubber adhesive, a silicon adhesive, and a polyvinyl ether adhesive as materials for the first adhesive layer.

JP 2005-536894 A

As described above, the heterojunction photovoltaic device has an amorphous semiconductor film on both surfaces of a crystalline semiconductor substrate.
Here, the amorphous semiconductor film is vulnerable to moisture and sodium.
For this reason, when a material having an insufficient barrier property against moisture or sodium is used as the material of the sealing layer, the amorphous semiconductor film is deteriorated.

Moreover, the material of the 1st contact bonding layer described in patent document 1 has very weak tolerance with respect to an ultraviolet-ray. For this reason, when using such a material, generally, the first adhesive layer is protected by including an ultraviolet absorber in the first sealing layer.
However, when the first sealing layer contains an ultraviolet absorber, ultraviolet light cannot be effectively used for power generation.

  The present invention has been made in view of the above problems, and provides a photovoltaic module that has a high degree of freedom in selecting a material for a sealing layer and can obtain better power generation efficiency.

The present invention
A photovoltaic module comprising photovoltaic elements,
The photovoltaic element is
A first conductivity type crystalline semiconductor substrate;
A first amorphous semiconductor film, a first conductive type second amorphous semiconductor film, a first translucent electrode film, a first electrode, on one surface side of the crystalline semiconductor substrate; In this order,
An intrinsic third amorphous semiconductor film, a second conductivity type fourth amorphous semiconductor film, a second translucent electrode film, and a second electrode are formed on the other surface side of the crystalline semiconductor substrate. And in this order,
The first amorphous semiconductor film is a first conductivity type having an impurity concentration lower than that of the second amorphous semiconductor film, or is intrinsic.
The photovoltaic module further includes
A plurality of first fine wires bonded and fixed to the first electrode on one surface of the photovoltaic element by a first adhesive layer;
The first resin having the plurality of first fine wirings sandwiched between the one surface of the photovoltaic element and bonded to the one surface of the photovoltaic element via the first adhesive layer With film,
A translucent first protective layer;
A first sealing layer filled between the first protective layer and the first resin film;
A plurality of second fine wires bonded and fixed to the second electrode on the other surface of the photovoltaic element by a second adhesive layer;
The second resin having the plurality of second fine wirings sandwiched between the other surface of the photovoltaic element and bonded to the other surface of the photovoltaic element via the second adhesive layer With film,
A second protective layer;
A second sealing layer filled between the second protective layer and the second resin film;
With
The first adhesive layer provides a photovoltaic module composed of a resin material containing a copolymer of ethylene and an unsaturated carboxylic acid.

  According to the present invention, it is possible to provide a photovoltaic module that has a high degree of freedom in selecting the material of the sealing layer and that can obtain better power generation efficiency.

It is typical sectional drawing which shows the layer structure of the photovoltaic module which concerns on embodiment. It is a typical top view of the photovoltaic module concerning an embodiment. It is typical sectional drawing which shows a part of photovoltaic module which concerns on embodiment. It is typical sectional drawing which shows an example of the wiring sheet used for manufacture of the photovoltaic module which concerns on embodiment. It is a typical top view which shows an example of the wiring sheet used for manufacture of the photovoltaic module which concerns on embodiment. It is typical sectional drawing which shows another example of the wiring sheet used for manufacture of the photovoltaic module which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

As shown in FIG. 1, the photovoltaic module 100 according to this embodiment includes a photovoltaic element 10.
The photovoltaic device 10 includes a first conductive type crystalline semiconductor substrate 11, a first amorphous semiconductor film 12 and a first conductive type second semiconductor film on one surface side of the crystalline semiconductor substrate 11. The amorphous semiconductor film 13, the first translucent electrode film 14, and the first electrode 15 are provided in this order.
The photovoltaic element 10 further includes an intrinsic third amorphous semiconductor film 16, a second conductivity type fourth amorphous semiconductor film 17, and a second conductive film on the other surface side of the crystalline semiconductor substrate 11. The translucent electrode film 18 and the second electrode 19 are provided in this order.
The first amorphous semiconductor film 12 is a first conductivity type having an impurity concentration lower than that of the second amorphous semiconductor film 13 or is intrinsic.
The photovoltaic module 100 further includes a plurality of first fine wirings 21 bonded and fixed to the first electrode 15 on one surface of the photovoltaic element 10 by the first adhesive layer 22, and one surface of the photovoltaic element 10. A first resin film 23 sandwiched between the plurality of first fine wirings 21 and bonded to one surface of the photovoltaic element 10 via the first adhesive layer 22, and a translucent first protective layer 40 and a first sealing layer 30 filled between the first protective layer 40 and the first resin film 23.
The photovoltaic module 100 further includes a plurality of second fine wirings 51 bonded and fixed to the second electrode 19 on the other surface of the photovoltaic element 10 by the second adhesive layer 52, and the other surface of the photovoltaic element 10. A second resin film 53 bonded to the other surface of the photovoltaic device 10 via the second adhesive layer 52, a second protective layer 70, And a second sealing layer 60 filled between the second protective layer 70 and the second resin film 53.
And the 1st contact bonding layer 22 is comprised by the resin material containing the copolymer (for example, ionomer) of ethylene and unsaturated carboxylic acid.
Details will be described below.

  The photovoltaic device 10 is a heterojunction photovoltaic device.

The conductivity type of each component of the photovoltaic element 10 will be described. The crystalline semiconductor substrate 11 is, for example, n-type. In this case, the second amorphous semiconductor film 13 is n-type, and the first amorphous semiconductor film 12 is intrinsic or n ⁻ -type (n-type having a lower impurity concentration than the second amorphous semiconductor film 13). The fourth amorphous semiconductor film 17 is p-type.

  The crystal semiconductor substrate 11 is not particularly limited as long as it is a crystal having n-type semiconductor characteristics, and a known substrate can be used. Examples of the n-type crystal semiconductor composing the crystalline semiconductor substrate 11 include SiC, SiGe, SiN and the like in addition to silicon (Si). Silicon is preferable from the viewpoint of productivity. The crystalline semiconductor substrate 11 may be a single crystal or a polycrystal. Both surfaces (one surface and the other surface) of the crystalline semiconductor substrate 11 are preferably subjected to uneven processing (not shown) in order to make light confinement due to irregular reflection of light more effective. For example, a large number of pyramidal irregularities can be formed by immersing the substrate material in an etching solution containing about 1 to 5% by mass of sodium hydroxide or potassium hydroxide.

  The first amorphous semiconductor film 12, the second amorphous semiconductor film 13, the third amorphous semiconductor film 16, and the fourth amorphous semiconductor film 17 are each made of a silicon thin film. it can.

The first amorphous semiconductor film 12 is stacked on one surface of the crystalline semiconductor substrate 11 (upper surface in FIG. 1).
The second amorphous semiconductor film 13 is stacked on one surface (the upper surface in FIG. 1) of the first amorphous semiconductor film 12.
The total thickness of the first amorphous semiconductor film 12 and the second amorphous semiconductor film 13 is not particularly limited, but is preferably 1 nm to 20 nm, for example, and more preferably 4 nm to 10 nm. By setting the film thickness within such a range, it is possible to reduce the short-circuit current and the occurrence of carrier recombination in a well-balanced manner.

The first translucent electrode film 14 is stacked on one surface (the upper surface in FIG. 1) of the second amorphous semiconductor film 13.
Examples of the transparent electrode material constituting the first translucent electrode film 14 include indium tin oxide (ITO), tungsten-doped indium oxide (InWO), and cerium-doped indium oxide (ITO). Well-known materials such as Indium Cerium Oxide (ICO), IZO (Indium Zinc Oxide), AZO (aluminum doped ZnO), and GZO (gallium doped ZnO) can be exemplified.

  The third amorphous semiconductor film 16 is stacked on the other surface (the lower surface in FIG. 1) of the crystalline semiconductor substrate 11. In other words, the third amorphous semiconductor film 16 is interposed between the crystalline semiconductor substrate 11 and the fourth amorphous semiconductor film 17. The film thickness of the third amorphous semiconductor film 16 is not particularly limited, but may be, for example, 1 nm or more and 10 nm or less.

  The fourth amorphous semiconductor film 17 is stacked on one surface (the lower surface in FIG. 1) of the third amorphous semiconductor film 16. Although the film thickness of the 4th amorphous semiconductor film 17 is not specifically limited, For example, 1 nm or more and 20 nm or less are preferable, and 3 nm or more and 10 nm or less are more preferable.

  The second translucent electrode film 18 is stacked on one surface (the lower surface in FIG. 1) of the fourth amorphous semiconductor film 17. The material constituting the second translucent electrode film 18 is the same as that of the first translucent electrode film 14.

Here, intrinsic means that impurities are not intentionally doped. Therefore, the intrinsic amorphous semiconductor film includes impurities that are originally included in the raw material and impurities that are unintentionally mixed in the manufacturing process.
Moreover, an amorphous system means that not only an amorphous body but a microcrystal body is included.
The n-type amorphous semiconductor film refers to a film containing impurities of about 10 ⁻⁵ or more with respect to silicon as a number density ratio of elements contained in the thin film.

The first electrode 15 is, for example, a finger electrode, or a metal film formed on the entire surface of one surface (the upper surface in FIG. 1) of the first light-transmissive electrode film 14.
Similarly, the second electrode 19 is, for example, a finger electrode or a metal film formed on the entire surface of one surface (the lower surface in FIG. 1) of the second translucent electrode film 18.
As a material of the finger electrode constituting the first electrode 15 and the second electrode 19, a conductive adhesive such as a silver paste or a metal conductor such as a copper wire can be used. The width of the finger electrode is, for example, about 20 μm or more and 80 μm or less.
In addition, as a material of the metal film constituting the first electrode 15 and the second electrode 19, silver, a silver alloy, an aluminum alloy, or the like can be used.

The plurality of first fine wirings 21 are, for example, a plurality of wires or bus bars arranged in parallel to each other.
Hereinafter, a configuration when the first fine wiring 21 is a wire will be described.
In this case, the first fine wiring 21 has a core 21a and a low melting point metal film 21b coated on the surface of the core 21a. Examples of the metal material of the core 21a include copper. An example of the metal material of the low melting point metal film 21b is an alloy of indium and tin.
The diameter of the first fine wiring 21 is preferably 100 μm or more and 400 μm or less, and more preferably 200 μm or more and 300 μm or less.
The second fine wiring 51 is configured in the same manner as the first fine wiring 21.

In addition, when the 1st electrode 15 is a finger electrode, the some 1st fine wiring 21 is orthogonally crossed with the 1st electrode 15 (refer FIG. 2).
Similarly, when the second electrode 19 is a finger electrode, the plurality of second fine wirings 51 are orthogonal to the second electrode 19.

The first adhesive layer 22 is translucent.
The 1st contact bonding layer 22 is comprised by the resin material containing the copolymer of ethylene and unsaturated carboxylic acid.

  Examples of the copolymer of ethylene and unsaturated carboxylic acid include an ionomer of a copolymer of ethylene and unsaturated carboxylic acid. The ionomer of the copolymer of ethylene and unsaturated carboxylic acid may contain a metal species derived from an alkali metal such as lithium or sodium, or a polyvalent metal such as calcium, magnesium, cerium, zinc or aluminum. it can. Generally, ionomers are known to have excellent transparency and a high storage elastic modulus E ′ at high temperatures. Further, the ionomer neutralization degree of the copolymer of ethylene and unsaturated carboxylic acid according to this embodiment is preferably 80% or less, and more preferably 60% or less from the viewpoint of adhesiveness. Most preferably, it is 40% or less.

  The unsaturated carboxylic acid component in the ionomer of a copolymer of ethylene and an unsaturated carboxylic acid or a copolymer of ethylene and an unsaturated carboxylic acid includes acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, maleic acid. Examples thereof include monomethyl acid and maleic anhydride. Among these, (meth) acrylic acid is preferable as the unsaturated carboxylic acid component. Therefore, the ethylene / unsaturated carboxylic acid copolymer is preferably an ethylene / (meth) acrylic acid copolymer. The ethylene / unsaturated carboxylic acid copolymer according to the present embodiment is not limited to a binary copolymer of ethylene and unsaturated carboxylic acid, but an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer. Also included are multicomponent copolymers containing ethylene and unsaturated carboxylic acids. Examples of the unsaturated carboxylic acid ester component in the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer include alkyl esters having 1 to 20 carbon atoms of various carboxylic acids used as the unsaturated carboxylic acid component described above. It is done. Specifically, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a 2-ethylhexyl group, and an isooctyl group.

  The content of unsaturated carboxylic acid units such as (meth) acrylic acid units in the copolymer of ethylene and unsaturated carboxylic acid or its ionomer according to the present embodiment is preferable from the viewpoint of realizing excellent ultraviolet transparency. Is 2 wt% or more and 30 wt% or less, more preferably 9 wt% or more and 25 wt% or less, and most preferably 12 wt% or more and 20 wt% or less.

  From the viewpoint of improving the transparency and adhesiveness of the copolymer of ethylene and unsaturated carboxylic acid, the content of the unsaturated carboxylic acid with respect to the total amount of the copolymer is preferably 1% by weight or more. On the other hand, the content of the unsaturated carboxylic acid with respect to the total amount of the copolymer is preferably 20% by weight or less, and more preferably 15% by weight or less from the viewpoint of reducing hygroscopicity.

  The copolymer of ethylene and unsaturated carboxylic acid according to this embodiment can be obtained by performing a radical copolymerization reaction under high temperature and high pressure conditions. Further, an ionomer of a copolymer of ethylene and unsaturated carboxylic acid can be obtained by reacting a copolymer of ethylene and unsaturated carboxylic acid with a metal compound.

  Examples of the resin material forming the first adhesive layer 22 include antioxidants such as hydroquinone monobenzyl ether and triphenyl phosphite, thermal stabilizers such as lead stearate and barium laurate, fine titanium oxide, Various additives such as fillers such as zinc oxide, pigments, dyes, lubricants, antiblocking agents, foaming agents, foaming aids, crosslinking agents, crosslinking aids, flame retardants, and the like may be blended.

  In the resin material forming the first adhesive layer 22, for example, a metal fatty acid salt such as cadmium or barium may be arbitrarily blended as a discoloration preventing agent.

The light transmittance at a wavelength of 350 nm of the first adhesive layer 22 measured according to JIS-K7105 is preferably 70% or more. By doing so, light energy derived from ultraviolet rays can be efficiently contributed to power generation. In this specification, light energy derived from ultraviolet rays refers to light energy derived from light in a wavelength region of less than 380 nm.
By using the above-described material as the material of the first adhesive layer 22, such light transmittance can be realized.
Such a light transmittance can be realized more reliably by adopting a configuration in which the first adhesive layer 22 does not substantially contain an ultraviolet absorber.
In addition, the light transmittance in the wavelength of 350 nm of the 1st contact bonding layer 22 measured according to JIS-K7105 becomes like this. Preferably, it is 75% or more, More preferably, it is 80% or more. By doing so, it becomes possible to more effectively contribute light energy derived from ultraviolet rays to power generation.

  The layer thickness T (FIG. 3) of the first adhesive layer 22 can be, for example, 8 μm or more and 100 μm or less, and preferably 16 μm or more and 75 μm or less. As will be described later, when the first fine wiring 21 is a wire having a diameter D, the layer thickness T of the first adhesive layer 22 is preferably set in a range of D / 6 ± D / 12. That is, as an example, when the first fine wiring 21 is a wire having a diameter of 300 μm, the layer thickness T can be set to 25 μm or more and 75 μm or less. Here, the layer thickness T of the first adhesive layer 22 is a layer thickness in a range where the layer thickness of the first adhesive layer 22 is substantially constant in the interval between adjacent wires (see FIG. 3). ).

The 1st resin film 23 is formed with the material containing 1 or more selected from the group which consists of a fluororesin and an acrylic resin, for example.
Examples of the fluororesin include tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polychlorotriethylene. Examples include fluoroethylene (PCTFE), chlorotrifluoroethylene / ethylene copolymer (PCTFEE), polyvinyl fluoride (PVF), and polyvinylidene fluoride (PVDF). Among these, at least one selected from the group consisting of tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and polyvinyl fluoride (PVF) is preferable.
Examples of the acrylic resin include acrylic acid ester polymers and methacrylic acid ester polymers. Among these, a methacrylic resin that is a polymer mainly composed of methyl methacrylate units is preferable. Examples of the methacrylic resin include polymethyl methacrylate (PMMA), a copolymer of methyl methacrylate and another monomer, and the like.
The thickness of the 1st resin film 23 can be 5 micrometers or more and 100 micrometers or less (preferably 10 micrometers or more and 80 micrometers or less), for example.

The first sealing layer 30 is translucent.
The material of the first sealing layer 30 may be the same as that of the first adhesive layer 22, TPO (olefin elastomer), or silicon resin.
The layer thickness of the 1st sealing layer 30 can be 300 micrometers or more and 500 micrometers or less, for example.
Here, the thickness of the first sealing layer 30 is set to be thicker than the protruding length of the first fine wiring 21 from the adhesive layer 22 (the protruding length to the first protective layer 40 side).
Here, the surface of the first protective layer 40 on the first sealing layer 30 side may be embossed. In that case, it is preferable to fill the unevenness of the embossment in the first protective layer 40 with the first sealing layer 30. For this reason, it is preferable that the thickness of the first sealing layer 30 has at least a thickness obtained by adding the height of the unevenness of the emboss to the protruding length of the first fine wiring 21 from the adhesive layer 22.

  The first protective layer 40 is a translucent substrate. Examples of the material of the first protective layer 40 include glass, acrylic resin, polycarbonate, polyester, fluorine-containing resin, and the like.

  The second protective layer 70 may be a translucent substrate similar to the first protective layer 40, or may be a non-translucent (eg, light reflective) backsheet. As the back sheet, for example, a single-layer or multi-layer sheet formed of a metal such as tin, aluminum, and stainless steel, an inorganic material such as glass, a polyester, an inorganic vapor-deposited polyester, a fluorine-containing resin, and a thermoplastic resin such as polyolefin. Is mentioned.

When the second protective layer 70 is a translucent substrate, the photovoltaic module 100 can receive light on both sides (the first protective layer 40 side and the second protective layer 70 side). In this case, the second adhesive layer 52 can be made of the same material as the first adhesive layer 22. The second resin film 53 can be made of the same material as the first resin film 23.
The second sealing layer 60 can be made of the same material as the first sealing layer 30. However, when light reception on both sides is not necessary, the second sealing layer 60 may contain a pigment or the like as described later.

In the case where the second protective layer 70 is a non-translucent back sheet, the light receiving surface of the photovoltaic module 100 is one side (the first protective layer 40 side). In this case, the material of the second adhesive layer 52 can be the same resin material as that of the first adhesive layer 22.
In addition, the material of the second sealing layer 60 when the second protective layer 70 is a non-translucent backsheet may be the same as that of the first sealing layer 30, but in this case, the second sealing layer 60 Since the stop layer 60 is not required to be transparent, it is preferable to blend a pigment, a dye, and an inorganic filler from the viewpoint of improving the power generation efficiency. Examples of the pigment include white pigments such as titanium oxide and calcium carbonate, blue pigments such as ultramarine, and black pigments such as carbon black. In particular, blending an inorganic pigment such as titanium oxide is preferable from the viewpoint of preventing the insulation resistance of the photovoltaic module 100 from being lowered. The amount of the inorganic pigment is preferably 0 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, based on 100 parts by weight of the ethylene / polar monomer copolymer. Most preferably, it is 4 parts by weight or more and 50 parts by weight or less.
The material of the second resin film 53 when the second protective layer 70 is a non-translucent back sheet may be the same as that of the first resin film 23, or may be other resin materials.

The second adhesive layer 52 can have the same thickness as the first adhesive layer 22.
That is, when the second fine wiring 51 is a wire having a diameter D, the layer thickness T of the second adhesive layer 52 is preferably set in a range of D / 6 ± D / 12. That is, as an example, when the second fine wiring 51 is a wire having a diameter of 300 μm, the layer thickness T can be set to 25 μm or more and 75 μm or less.
The second resin film 53 can have the same thickness as the first resin film 23.

The second protective layer 70 may be a hard substrate such as a glass substrate, or may be a flexible resin sheet.
When the second protective layer 70 is a hard substrate such as a glass substrate, the second adhesive layer 52 can have the same thickness as the first adhesive layer 22.
On the other hand, when the second protective layer 70 is a flexible resin sheet, even if the second fine wiring 51 protrudes on the back surface side (the lower side in FIG. 1) of the second sealing layer 60, The second protective layer 70 can be deformed along the protruding portion of the second fine wiring 51 (the surface of the second protective layer 70 has a shape reflecting the protruding portion of the second fine wiring 51). Therefore, the second protective layer 70 can suitably protect the back surface of the photovoltaic module 100 while being in close contact with the second sealing layer 60 and the second fine wiring 51. For this reason, when the second protective layer 70 is a flexible resin sheet, the second sealing layer 60 can be made thinner than the first sealing layer 30. Even when the second protective layer 70 is a flexible resin sheet, it is needless to say that the thickness of the second sealing layer 60 may be equal to the thickness of the first sealing layer 30.

  Note that a plurality of photovoltaic modules 100 are usually used in series. By using a plurality of photovoltaic modules 100 connected in series, the generated voltage can be increased.

  Next, an example of a method for manufacturing the photovoltaic module 100 will be described.

  First, in the photovoltaic device 10, the first amorphous semiconductor film 12, the second amorphous semiconductor film 13, and the first light-transmissive electrode film 14 are arranged in this order on one surface of the crystalline semiconductor substrate 11. On the other hand, the third amorphous semiconductor film 16, the fourth amorphous semiconductor film 17, and the second translucent electrode film 18 are formed in this order on the other surface of the crystalline semiconductor substrate 11. Further, the first electrode 15 is formed on one surface (the upper surface in FIG. 1) of the first light-transmissive electrode film 14, and the first surface (the lower surface in FIG. 1) of the second light-transmissive electrode film 18. It is obtained by forming the second electrodes 19 respectively.

  Next, for example, a first wiring sheet (see the wiring sheet 200 shown in FIGS. 4 and 5) in which the first resin film 23, the first adhesive layer 22, and the first fine wiring 21 are integrated, and the first protection. A layer 40 and a sheet-like first sealing layer 30 are prepared.

Here, the wiring sheet 200 will be described.
The wiring sheet 200 includes a resin film (the first resin film 23 or the second resin film 53) and an adhesive layer (the first adhesive layer 22 or the second adhesive layer 52) laminated on each other, and the resin film side in the adhesive layer. Has fine wiring (first fine wiring 21 or second fine wiring 51) provided on the opposite surface.
As shown in FIG. 4, it is preferable that a part of each fine wiring is embedded in the adhesive layer, and by doing so, the integrity of the adhesive layer and the fine wiring can be improved. .
In addition, as shown in FIG. 5, the fine wiring is preferably a plurality of wires arranged in parallel to each other, and in this way, the amount of the metal material used for forming the fine wiring is reduced. Can be reduced.
The resin film is formed of a material including one or more selected from the group consisting of a fluororesin and an acrylic resin. The thickness of the resin film is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 80 μm or less. When the light receiving surface of the photovoltaic module 100 is a single surface, the first resin film 23 arranged on the light receiving surface side preferably has a light transmittance of 70% or more at a wavelength of 350 nm measured according to JIS-K7105. . By doing so, it is possible to realize a module capable of efficiently contributing to the power generation by light energy derived from ultraviolet rays. Moreover, when the light-receiving surface of the photovoltaic module 100 is both surfaces, it is preferable that the 2nd resin film 53 is 70% or more of the light transmittance in the wavelength of 350 nm measured according to JIS-K7105. By doing so, it is possible to realize a module capable of efficiently contributing to the power generation by light energy derived from ultraviolet rays.

Next, the first wiring sheet is interposed between the first electrode 15 on one side of the photovoltaic element 10 and the first protective layer 40, and between the first wiring sheet and the first protective layer 40. The first sealing layer 30 is interposed.
Similarly, a second wiring sheet (see the wiring sheet 200 shown in FIGS. 4 and 5) in which the second resin film 53, the second adhesive layer 52, and the second fine wiring 51 are integrated, and the second protective layer 70. And a sheet-like second sealing layer 60 are prepared.
Then, the second wiring sheet is interposed between the second electrode 19 on the other surface of the photovoltaic element 10 and the second protective layer 70, and the second wiring sheet is interposed between the second wiring sheet and the second protective layer 70. Two sealing layers 60 are interposed.
Then, these are collectively heated and pressurized from both sides, whereby the first fine wiring 21 is welded to the first electrode 15 via the first adhesive layer 22 and the first sealing layer 30 is interposed. The first resin film 23 and the first protective layer 40 are welded, the second fine wiring 51 is welded to the second electrode 19 through the second adhesive layer 52, and the second sealing layer 60 is used. The second resin film 53 and the second protective layer 70 are welded.
At this time, the core 21 a and the first electrode 15 are welded by melting the low melting point metal film 21 b on the surface layer of the first fine wiring 21.
Similarly, the low melting point metal film (not shown) on the surface layer of the second fine wiring 51 is melted, so that the core (not shown) of the second fine wiring 51 and the second electrode 19 are welded.
Thus, the photovoltaic module 100 can be obtained.

  Here, the example in which the wiring sheet 200 having the structure shown in FIG. 4 is used as the first wiring sheet and the second wiring sheet has been described, but the structure shown in FIG. 6 is used as the first wiring sheet and the second wiring sheet. The wiring sheet 200 may be used. In this case, a resin film (first resin film 23, second resin film 53) is prepared separately from the wiring sheet 200 (first wiring sheet, second wiring sheet).

Here, according to the study by the present inventor, when the plurality of first fine wirings 21 are a plurality of wires arranged in parallel to each other, when the outer diameter of the wires is D (FIG. 3), The layer thickness T (FIG. 3) of the one adhesive layer 22 is preferably set in a range of D / 6 ± D / 12. For example, when the outer diameter D of the wire is 300 μm, the layer thickness T is preferably in the range of 50 μm ± 25 μm.
By doing so, as shown in FIG. 3, the first fine wiring 21 can be more securely welded to the first electrode 15 by suppressing the floating of the first fine wiring 21 from the first electrode 15. In addition, the first resin film 23 can be bonded to the first electrode 15 with sufficient adhesive strength by the first adhesive layer 22. In addition, by setting the layer thickness T of the first adhesive layer 22 to D / 6-D / 12 or more, reliability is reduced due to the formation of voids (cavities) around the first fine wiring 21. Can be suppressed.

Similarly, when the plurality of second fine wirings 51 are a plurality of wires arranged in parallel to each other and the outer diameter of the wires is D, the layer thickness T of the second adhesive layer 52 is D / 6. It is preferable to be set within a range of ± D / 12.
By doing so, it is possible to suppress the floating of the second fine wiring 51 from the second electrode 19, and more reliably weld the second fine wiring 51 to the second electrode 19, and the second resin. The film 53 can be adhered to the second electrode 19 with sufficient adhesive strength by the second adhesive layer 52. In addition, by setting the layer thickness T of the second adhesive layer 52 to be equal to or greater than D / 6-D / 12, a reduction in reliability due to the formation of voids around the second fine wiring 51 is suppressed. Can do.

According to the photovoltaic module 100 according to the embodiment as described above, the resin including the heterojunction photovoltaic element 10 and the first adhesive layer 22 including a copolymer of ethylene and unsaturated carboxylic acid. It is composed of materials. Here, a copolymer of ethylene and an unsaturated carboxylic acid (such as an ionomer) has a characteristic of low moisture permeability. For this reason, even if a material having a relatively high moisture permeability is selected as the first protective layer 40, the second amorphous semiconductor film 13 and the first amorphous semiconductor are formed by the first adhesive layer 22. The membrane 12 can be protected from moisture. Therefore, for example, the sodium component contained in the first protective layer 40 can also be prevented from migrating to the second amorphous semiconductor film 13 and the first amorphous semiconductor film 12 side together with moisture.
For this reason, the freedom degree of selection of the material of the 1st sealing layer 30 becomes high.
In addition, copolymers of ethylene and unsaturated carboxylic acids (such as ionomers) have good resistance to ultraviolet rays. Therefore, even when the first sealing layer 30 does not substantially contain the ultraviolet absorber, it is possible to ensure good resistance of the first adhesive layer 22. For this reason, since ultraviolet light can be used effectively for power generation, better power generation efficiency can be obtained.

  In particular, when the copolymer in the resin material (resin material containing a copolymer of ethylene and unsaturated carboxylic acid) constituting the first adhesive layer 22 is an ionomer, good transparency of the first adhesive layer 22; Since the ultraviolet resistance and the low transmittance of moisture can be realized, the above-described effects can be obtained more reliably.

Further, by setting the light transmittance at a wavelength of 350 nm of the first adhesive layer 22 measured according to JIS-K7105 to 70% or more, it becomes possible to efficiently contribute to the power generation of light energy derived from ultraviolet rays. Therefore, good power generation efficiency of the photovoltaic module 100 can be obtained. The light transmittance is more preferably 75% or more, and more preferably 80% or more.
Regarding the light transmittance of the first sealing layer 30, the light transmittance at a wavelength of 350 nm of the first sealing layer 30 measured according to JIS-K7105 can be set to 70% or more. Good power generation efficiency can be obtained. This light transmittance is also preferably 75% or more, and more preferably 80% or more.

  Further, in the case where the plurality of first fine wirings 21 are a plurality of wires arranged in parallel to each other, and the outer diameter of the wire is D, the layer thickness T of the first adhesive layer 22 is D / 6 ± D / 12 can be set. By doing so, as shown in FIG. 3, the first fine wiring 21 can be more securely welded to the first electrode 15 by suppressing the floating of the first fine wiring 21 from the first electrode 15. In addition, the first resin film 23 can be bonded to the first electrode 15 with sufficient adhesive strength by the first adhesive layer 22.

When the second protective layer 70 is translucent, the second adhesive layer 52 is made of a resin material containing a copolymer of ethylene and an unsaturated carboxylic acid, like the first adhesive layer 22. be able to. By doing so, the same effect as that of the first adhesive layer 22 is obtained by the second adhesive layer 52.
That is, even if a material having a relatively high moisture permeability is selected as the second protective layer 70, the fourth amorphous semiconductor film 17 and the third amorphous semiconductor film are formed by the second adhesive layer 52. 16 can be protected from moisture. Therefore, for example, migration of the sodium component contained in the second protective layer 70 to the fourth amorphous semiconductor film 17 and the third amorphous semiconductor film 16 side together with moisture can be suppressed.
For this reason, the freedom degree of selection of the material of the 2nd protective layer 70 becomes high.
In addition, copolymers of ethylene and unsaturated carboxylic acids (such as ionomers) have good resistance to ultraviolet rays. Therefore, even if the second protective layer 70 does not substantially contain the ultraviolet absorber, it is possible to ensure good resistance of the second adhesive layer 52. For this reason, since ultraviolet light can be used effectively for power generation, better power generation efficiency can be obtained.
In particular, when the copolymer in the resin material (resin material containing a copolymer of ethylene and unsaturated carboxylic acid) constituting the second adhesive layer 52 is an ionomer, good transparency of the second adhesive layer 52, Since the ultraviolet light resistance and the low moisture transmittance can be realized, the above-described effects can be obtained more reliably.

Further, by making the light transmittance at a wavelength of 350 nm of the second adhesive layer 52 measured according to JIS-K7105 for the second adhesive layer 52 to be 70% or more, light energy derived from ultraviolet rays contributes to power generation efficiently. Therefore, good power generation efficiency of the photovoltaic module 100 can be obtained. This light transmittance is also preferably 75% or more, and more preferably 80% or more.
Regarding the light transmittance of the second protective layer 70, the light transmittance at a wavelength of 350 nm of the second sealing layer 70 measured according to JIS-K7105 can be set to 70% or more. Power generation efficiency can be obtained. This light transmittance is also preferably 75% or more, and more preferably 80% or more.

  In addition, the conductivity type of each component of the photovoltaic device 10 may be reversed from the above example.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

The photovoltaic module according to the example was manufactured by the following method.
A light-transmitting substrate (first protective layer), a first sealing layer (using a resin sheet 1 described later), a first wiring sheet (using a wiring sheet 1 described later), and a photovoltaic element were stacked in this order. Furthermore, on the photovoltaic element, a second wiring sheet (using a wiring sheet 1 described later), a second sealing layer (using a resin sheet 3 described later), and a back sheet (second protective layer) in this order. These were stacked and laminated using a vacuum laminator to produce a photovoltaic module.

  The photovoltaic module according to the comparative example uses the resin sheet 4 described later as the first sealing layer and the second sealing layer, and uses the wiring sheet 2 described later as the first wiring sheet and the second wiring sheet, respectively. Other than that, it produced similarly to the photovoltaic module concerning an Example.

<Wiring sheet 1>
A base sheet (corresponding to a first resin film or a second resin film) formed of tetrafluoroethylene / ethylene copolymer (ETFE) having a thickness of 25 μm, and a thickness formed on one surface of the base sheet A metal micro-wiring with a diameter of 300 μm is arranged at equal intervals on the surface of the sheet having a thickness of 75 μm resin sheet 2 (which will be described later: corresponding to the first adhesive layer or the second adhesive layer) and thermocompression-bonded. By doing this, the wiring sheet 1 was produced. In the obtained wiring sheet 1, wires were embedded in the resin sheet 2.

<Wiring sheet 2>
The wiring sheet 2 was produced by heat-pressing the metal fine wiring with a diameter of 300 micrometers on the surface of the resin sheet 4 (after-mentioned) with a thickness of 100 micrometers, arranging it at equal intervals. In the obtained wiring sheet 2, wires were embedded in the resin sheet 4.

Each of the resin sheets 1 to 4 includes at least one of an A layer ((A) -1 or (A) -2) described later and a B layer ((B) -1 or (B) -2) described later. It is a single layer or multilayer resin sheet having any one layer.
<Resin sheet 1>
The resin sheet 1 is a three-layer sheet having a structure in which (A) -1 which is a surface layer, (B) -1 which is an intermediate layer, and (A) -1 which is a surface layer are laminated in this order. It has become.

<Resin sheet 2>
The resin sheet 2 is a single-layer sheet and is configured by (A) -1.

<Resin sheet 3>
The resin sheet 3 is a three-layer sheet, and has a structure in which (A) -2 which is a surface layer, (B) -2 which is an intermediate layer, and (A) -2 which is a surface layer are laminated in this order. It has become.

<Resin sheet 4>
The resin sheet 4 is a single layer sheet and is made of an ethylene-vinyl acetate copolymer.

  Hereinafter, the raw materials and blending of each layer will be described.

<Raw material>
-1. Resin
Resin / ionomer for (A layer) 1: Zinc ionomer (degree of neutralization 10) of ethylene / methacrylic acid / butyl acrylate terpolymer (methacrylic acid unit content = 5 mass%, butyl acrylate 7 mass%) %, MFR11g / 10min)
Ionomer 2: Zinc ionomer of ethylene / methacrylic acid copolymer (methacrylic acid unit content = 8.5% by mass) (neutralization degree 18%, MFR 6 g / 10 min)

Resin and ionomer for (B layer): Zinc ionomer of ethylene / methacrylic acid / butyl acrylate terpolymer (methacrylic acid unit content = 5 mass%, butyl acrylate 7 mass%) (degree of neutralization 10) %, MFR11g / 10min)
-Ionomer 4: Zinc ionomer of ethylene / methacrylic acid copolymer (methacrylic acid unit content = 12% by mass) (degree of neutralization 36%, MFR 1.5 g / 10 min)

-2. Additive-
Antioxidant: Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (manufactured by BASF, Irganox 1010)
UV absorber: 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenolLight stabilizer: bis (2,2,6,6, -tetramethyl-4-piperidyl ) Sebacate silane coupling agent: N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane

In addition, as the stabilizer masterbatch 1 used for the A layer and the B layer, the same resin as the resin for each layer, the antioxidant, the ultraviolet absorber, and the light stabilizer are resin / antioxidant / ultraviolet absorber. / Light stabilizer = 93.7 / 0.3 / 4/2 The mass ratio was used and the mixture was extruded in advance with a biaxial extruder.
Further, as the stabilizer buster batch 2 used for the A layer and the B layer, the same resin as the resin for each layer, an antioxidant, an ultraviolet absorber, and a light stabilizer are used as a resin / antioxidant / light stabilizer. = Mixed at a mass ratio of 96/2/2 and extruded in advance using a twin screw extruder.
As a white masterbatch, a white masterbatch PE-M 13N4700 manufactured by Dainichi Seika Kogyo Co., Ltd., an antioxidant, an ultraviolet absorber, and a light stabilizer are mixed at a predetermined mass ratio, and a twin-screw extruder is previously prepared. What was produced in (1) was used.

-3. Formulation
<A layer>
(A) -1: ionomer 1 / stabilizer masterbatch 2 / silane coupling agent = 90/10 / 0.2
(A) -2: ionomer 2 / stabilizer masterbatch 1 / white masterbatch / silane coupling agent = 85/10/5 / 0.2

<B layer>
(B) -1: ionomer 3 / stabilizer masterbatch 2 = 90/10
(B) -2: ionomer 4 / stabilizer master batch 1 / white master batch = 85/10/5

<Production of resin sheet>
Resin sheets 1 and 3, which are multilayer resin sheets, are each extruded into two types and three layers of multilayer cast molding machine (manufactured by Tanabe Plastics Machinery), feed block type (manufactured by EDI), 40 mmφ single screw extruder, and die width 500 mm extrusion It was produced by forming into a sheet shape at a processing temperature of 140 ° C. using a machine.
In addition, the resin sheets 2 and 4 which are single layer resin sheets are respectively obtained by using a single layer T-die molding machine (manufactured by Tanabe Plastics Machinery Co., Ltd.), a 40 mmφ single screw extruder, and a die width 500 mm extruder. In the same manner as in 1 and 3, the sheet was formed into a sheet shape at a processing temperature of 140 ° C.
In addition, the wiring sheet 1 having a laminated structure of the base sheet and the resin sheet 2 was manufactured by supplying the base sheet from the feeding portion of the molding machine and heat-pressing the resin sheet 2 with a nip roll at the time of molding. .

  Measurements and evaluations performed using the photovoltaic modules of Examples and Comparative Examples will be described below.

Wiring connection quality (EL image):
The wiring connection quality of the photovoltaic modules according to the examples and comparative examples was evaluated by an EL (electroluminescence) method. That is, an EL image was acquired in a state where a current was inputted to each photovoltaic module to emit light, and the quality was evaluated.
For obtaining the EL image of each photovoltaic module, an EL image inspection device (manufactured by ITES, PVX100) was used. The measurement conditions for acquiring the EL image were as follows: shutter time 15 seconds, aperture 8, ISO sensitivity 800, input voltage 0.73V to the photovoltaic module, and input current 8A to the photovoltaic module.
And the obtained EL image was confirmed visually and the quality of wiring connection was evaluated.
The evaluation results were as follows: ○: no shadow (good connection), ×: shadow (part of wiring connection was difficult).
The results were ○ in the example and × in the comparative example.

Power generation efficiency (Pmax):
About the photovoltaic module which concerns on an Example and a comparative example, power generation efficiency (Pmax) was measured.
That is, while changing the bias voltage input to each photovoltaic module, the current was measured, and the obtained data was plotted to obtain an IV curve (not shown).
Here, in the measurement of current, Sumitomo Heavy Industries, Ltd. M130-DDYTB383 J-JA was used.
The bias voltage is changed in the range of -0.1V to 0.8V. Within this range, the bias voltage is changed in increments of 0.02V from -0.1V to 0.4V. The bias voltage was changed in increments of 0.01V up to 0.8V.
Further, AM1.5G and 1SUN were adopted as measurement conditions, and measurement was performed at 25 ° C.
Then, with respect to the obtained IV curve, a point at which the product of voltage and current becomes maximum, that is, “maximum output = power generation efficiency (Pmax)” was obtained.
As a result, the power generation efficiency (Pmax) was 21.1 in the example and 19.8 in the comparative example.

Fill factor (FF):
Furthermore, the fill factor (FF) of the photovoltaic module which concerns on an Example and a comparative example was calculated | required using the measurement result of said electric power generation efficiency (Pmax).
Here, the current when the voltage is 0 V is referred to as a short-circuit current (Isc), and the voltage when no current is flowing through the photovoltaic module is referred to as an open-circuit voltage (Voc).
The fill factor (FF) is power generation efficiency (Pmax) / (Voc × Isc), which is 0.789 in the example and 0.743 in the comparative example.

  Moreover, the measurement and evaluation performed using said wiring sheets 1 and 2 are demonstrated below.

-Light transmittance of the resin sheet at a wavelength of 350 nm: The light transmittance at a wavelength of 350 nm of the resin sheet was measured according to JIS-K7105 under the condition of 25 ° C. The unit is%.
In the wiring sheet 1 of the example, the light transmittance at a wavelength of 350 nm was 85%.
On the other hand, in the wiring sheet 2 of the comparative example, the light transmittance at a wavelength of 350 nm was 4.3%.

-Total light transmittance: Under the conditions of 25 degreeC, the total light transmittance of the resin sheet was measured according to JIS-K7105. The unit is%.
In the wiring sheet 1 of the example, the total light transmittance was 89.6%.
On the other hand, in the wiring sheet 2 of the comparative example, the total light transmittance was 92.2%.

DESCRIPTION OF SYMBOLS 10 Photoelectric power generation element 11 Crystal semiconductor substrate 12 1st amorphous semiconductor film 13 2nd amorphous semiconductor film 14 1st translucent electrode film 15 1st electrode 16 3rd amorphous semiconductor film 17 4th Amorphous semiconductor film 18 Second translucent electrode film 19 Second electrode 21 First fine wiring 21a Core 21b Low melting point metal film 22 First adhesive layer 23 First resin film 30 First sealing layer 40 First protection Layer 51 second fine wiring 52 second adhesive layer 53 second resin film 60 second sealing layer 70 second protective layer 100 photovoltaic module 200 wiring sheet

Claims (5)

A photovoltaic module comprising photovoltaic elements,
The photovoltaic element is
A first conductivity type crystalline semiconductor substrate;
A first amorphous semiconductor film, a first conductive type second amorphous semiconductor film, a first translucent electrode film, a first electrode, on one surface side of the crystalline semiconductor substrate; In this order,
An intrinsic third amorphous semiconductor film, a second conductivity type fourth amorphous semiconductor film, a second translucent electrode film, and a second electrode are formed on the other surface side of the crystalline semiconductor substrate. And in this order,
The first amorphous semiconductor film is a first conductivity type having an impurity concentration lower than that of the second amorphous semiconductor film, or is intrinsic.
The photovoltaic module further includes
A plurality of first fine wires bonded and fixed to the first electrode on one surface of the photovoltaic element by a first adhesive layer;
The first resin having the plurality of first fine wirings sandwiched between the one surface of the photovoltaic element and bonded to the one surface of the photovoltaic element via the first adhesive layer With film,
A translucent first protective layer;
A first sealing layer filled between the first protective layer and the first resin film;
A plurality of second fine wires bonded and fixed to the second electrode on the other surface of the photovoltaic element by a second adhesive layer;
The second resin having the plurality of second fine wirings sandwiched between the other surface of the photovoltaic element and bonded to the other surface of the photovoltaic element via the second adhesive layer With film,
A second protective layer;
A second sealing layer filled between the second protective layer and the second resin film;
With
The said 1st contact bonding layer is a photovoltaic module comprised by the resin material containing the copolymer of ethylene and unsaturated carboxylic acid.   The photovoltaic module according to claim 1, wherein the copolymer is an ionomer.   The photovoltaic module according to claim 1 or 2, wherein a light transmittance at a wavelength of 350 nm of the first adhesive layer measured according to JIS-K7105 is 70% or more. The plurality of first fine wirings are a plurality of wires arranged in parallel to each other,
If the outer diameter of the wire is D,
4. The photovoltaic module according to claim 1, wherein a thickness T of the first adhesive layer is set in a range of D / 6 ± D / 12. 5. The second protective layer is translucent;
The photovoltaic module according to any one of claims 1 to 4, wherein the second adhesive layer is made of a resin material containing a copolymer of ethylene and an unsaturated carboxylic acid.

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