JP2012109414A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module which improves production efficiency and light utilization efficiency.SOLUTION: A solar cell module 50 includes: a circuit board 20 in which circuit layers 22 are formed on a surface of an insulation base material 21; solar cells 50 disposed on a front surface side of the circuit board 20 and having electrodes 51 on a rear surface; a first sealing material 70 disposed between the circuit board 20 and the solar cells 50 and sealing the solar cells 50 from a rear surface side; and a second sealing material sealing the solar cells 50 from a front surface side. A sealing resin 71 of the first sealing material 70 includes a filler 72 and a pigment 73, and a conductive filler 72a which electrically connects the electrodes 51 and the circuit layers 22 is adopted as the filler 72. The pigment 73 performs wavelength conversion on wavelength light which transmits through the solar cells 50 to convert the light into wavelength light that the solar cells 50 can absorb.

Description

  The present invention relates to a solar cell module including a back contact type solar cell including both a positive electrode (P-type semiconductor electrode) and a negative electrode (N-type semiconductor electrode) on the back surface.

  In recent years, solar power generation, which is a power generation system using natural energy, has been rapidly spread. As shown in FIG. 5, a solar cell module for photovoltaic power generation includes a light transmissive substrate 202 disposed on the light receiving side, a back sheet 201 disposed on the back surface side, a light transmissive substrate 202 and a back. A large number of solar cells 203 are arranged between the sheets 201. The solar battery cell 203 is sealed by being sandwiched between sealing materials 204 such as an ethylene / vinyl acetate copolymer (EVA) film.

  Conventionally, in a solar cell module, a large number of solar cells 203, 203... Are electrically connected in series with a wiring member 205 having a width of 1 to 3 mm. Since the solar battery cell 203 is provided with a negative electrode (N-type semiconductor electrode) on the front surface side which is a light receiving surface of the sun and a positive electrode (P-type semiconductor electrode) on the back surface side, The wiring member 205 overlaps the light receiving surface of the battery cell 203, and the area efficiency of photoelectric conversion tends to be reduced. Furthermore, since the wiring member 205 has a structure that wraps around from the front side to the back side of the solar battery cell 203, the wiring member 205 may be disconnected due to a difference in thermal expansion of each member.

  In order to solve these problems, for example, in Patent Documents 1 and 2, both the positive electrode and the negative electrode are installed on the back surface of the solar battery cell, and these electrodes are electrically connected by the circuit layer on the substrate. Contact-type solar cells have been proposed. In the solar cell of this system, it is possible to connect in series on the back surface of the cell, and the light receiving area on the cell surface is not sacrificed, and the reduction of the area efficiency of photoelectric conversion can be prevented. Further, since it is not necessary to have a structure in which the wiring member is wrapped around from the front side to the back side, disconnection due to the difference in thermal expansion of each member can be prevented. In addition, mounting of a photovoltaic cell is performed by connecting an electrode and a circuit layer using a conductive adhesive before sealing a photovoltaic cell with a sealing material.

JP 2009-111122 A JP 2009-224597 A

However, in the above-described back contact solar cell module, even if the light is incident on the solar cell, a part of the light is transmitted to the back surface side without being absorbed by the solar cell. Therefore, due to the presence of sunlight that does not contribute to power generation, it has been difficult to sufficiently improve the light utilization efficiency.
Moreover, since mounting of the photovoltaic cell is performed using a conductive adhesive, there is a problem that the operation becomes complicated and the production efficiency is lowered.

  This invention is made | formed in view of such a subject, and it aims at providing the solar cell module which can aim at the improvement of the utilization efficiency of light, aiming at the improvement of production efficiency.

In order to solve the above problems, the present invention proposes the following means.
That is, a solar cell module according to the present invention includes a circuit board in which a circuit layer is formed on the surface of an insulating substrate, a solar battery cell disposed on the surface side of the circuit board and having an electrode on the back surface, A first sealing material interposed between the circuit board and the solar battery cell for sealing the solar battery cell from the back surface side; and a second sealing material for sealing the solar battery cell from the front surface side; The first sealing material contains a filler and a pigment in a sealing resin, and the filler includes a conductive filler capable of electrically connecting at least the electrode and the circuit layer, and the pigment However, it has the function to convert the wavelength light which permeate | transmits the said photovoltaic cell into the wavelength light which this photovoltaic cell can absorb.

According to the solar cell module having such characteristics, the conductivity between the electrode and the circuit layer is ensured by the conductive filler in the first sealing material interposed between the solar cell and the circuit layer. . That is, anisotropic conductivity by the conductive filler is expressed by sandwiching the first sealing material between the solar battery cell and the circuit board, thereby causing no short circuit in the solar battery cell or the circuit layer, The electrode and the circuit layer are electrically connected.
Moreover, the light which permeate | transmitted the photovoltaic cell and arrived in the 1st sealing material is wavelength-converted into the wavelength light which a photovoltaic cell can absorb by injecting into a pigment | dye. And the said wavelength-converted light injects into a photovoltaic cell again through reflection by a filler.

Moreover, in the solar cell module according to the present invention, the wavelength light transmitted through the solar cell is ultraviolet light, and the wavelength light that can be absorbed by the solar cell is visible light.
That is, in general, a solar battery cell has a property of transmitting ultraviolet light outside the wavelength range because the light absorption wavelength band is set in the visible light wavelength range. Therefore, ultraviolet light that has passed through the solar cells is converted into visible light by the dye in the first sealing material, and is incident again on the solar cells through reflection by the filler, thereby improving the light utilization efficiency. Is possible.

Furthermore, in the solar cell module according to the present invention, it is preferable that the pigment is dispersed and mixed in the resin.
Thereby, the wavelength of light that has passed through the solar cell and entered the first sealing material can be efficiently converted by the pigment dispersed and mixed in the sealing resin. Therefore, the light use efficiency can be further improved.

In the solar cell module according to the present invention, the pigment may be supported on the surface of the filler.
When the dye is dispersed and mixed in the sealing resin, the dispersed dyes condense with the passage of time, resulting in unevenness in the wavelength conversion of the light, resulting in a decrease in the light utilization efficiency. There is a fear.
In this respect, since the pigment is supported on the surface of the filler, self-condensation between the pigments can be avoided, and the light use efficiency can be maintained high over a long period of time.

Furthermore, in the solar cell module according to the present invention, the filler may be porous and the pigment may be supported in the pores of the filler.
By holding the pigment in the pores of the filler, the pigment can be protected from the surroundings, and deterioration over time can be prevented. In addition, since the electronic state of the dye is stabilized, the wavelength conversion function can be prevented from being lowered, and the wavelength conversion can be reliably performed over a long period.

  Furthermore, in the solar cell module according to the present invention, the insulating base material is preferably formed by impregnating a glass fiber with an insulating resin.

According to the solar cell module of the present invention, the electrode and the circuit layer are electrically connected by the conductive filler in the first sealing material interposed between the solar cell and the circuit layer. Therefore, it is not necessary to separately perform the mounting process of the solar battery cell, and the production efficiency can be improved.
In addition, since light that does not contribute to power generation that has passed through the solar cell can be converted to wavelength light that can be absorbed by the solar cell by the dye, it can be guided to the solar cell again through reflection by the filler. The light use efficiency can be improved.

It is a cross-sectional schematic diagram of the solar cell module of the embodiment of the present invention. It is the elements on larger scale of FIG. It is a figure explaining the relationship between a filler and a pigment | dye, Comprising: (a) is a pigment | dye isolate | separated from a filler, (b) is a pigment | dye carry | supported on the surface of a filler, (c) is a pigment | dye. It is a figure explaining the case where is supported in the filler. It is a figure explaining the other example of a 1st sealing material. It is a cross-sectional schematic diagram of the conventional solar cell module.

Hereinafter, embodiments of the solar cell module of the present invention will be described.
FIG. 1 shows a solar cell module of the present embodiment. The solar cell module 10 includes a circuit board 20, a back sheet 30 disposed on the back side of the circuit board 20, a translucent base material 40 disposed on the front side of the circuit board 20 and forming a light receiving surface, A solar battery cell 50 disposed between the circuit board 20 and the translucent substrate 40 and a sealing layer 60 for sealing the solar battery cell 50 are provided.

The circuit board 20 is configured by integrally laminating a circuit layer 22 on the surface of an insulating base material 21.
As the insulating substrate 21, a plate-shaped member made of a composite material containing fibers and resin, that is, a prepreg obtained by impregnating or applying a thermosetting resin to a fiber substrate and drying it is used. Examples of the fibers used for the insulating substrate 21 include glass fibers, aramid fibers, fluorine fibers, polyester fibers, polyarylate fibers, and the like. Among these, it is preferable to employ glass fiber from the viewpoint of affinity with thermosetting resin, insulation reliability, and material cost.

  The resin is preferably an addition polymerization type thermosetting resin that cures without generating by-products. Examples of the addition polymerization type thermosetting resin include epoxy resin, unsaturated polyester resin, phenol resin, diallyl phthalate resin, acrylic resin, cyanate resin, cyanate ester resin-epoxy resin, cyanate ester-maleimide resin, cyanide. Acid ester-maleimide-epoxy resin, maleimide resin, maleimide-vinyl resin, bisallylnadiimide resin, and the like can be given. A thermosetting resin may be used individually by 1 type, and may use 2 or more types together.

  The circuit layer 22 is a layer electrically connected to a solar battery cell 50 to be described later, and is laminated on the surface of the insulating base material 21 by pressure bonding. The circuit layer 22 has a circuit pattern for electrically connecting a plurality of solar cells 50 arranged on the insulating base material 21 in series. As a material constituting the circuit layer 22, a material having a low electric resistance, for example, copper, aluminum, iron-nickel alloy, or the like is used, but the material is formed from a material having a lower linear expansion coefficient than the resin constituting the circuit layer 22. It is preferable that In addition, a conductive polymer can be used as the material of the circuit layer 22.

  The back sheet 30 is a layer for adjusting air permeation, and is laminated and fixed to the back surface of the circuit board 20. The backsheet 30 is made of a material having long-term reliability such as weather resistance and insulation. For example, a fluororesin film, a low oligomer / heat-resistant polyethylene terephthalate (PET) film / polyethylene naphthalate (PEN) film, silica ( SiO2) vapor deposition film, aluminum foil or the like is used.

  The translucent substrate 40 is a member that is disposed on the outermost surface of the solar cell module 10 to form a light receiving surface, and for example, a glass substrate, a transparent resin substrate, or the like is used. Examples of the transparent resin constituting the transparent resin substrate include acrylic resin, polycarbonate, and polyethylene terephthalate.

  The solar battery cell 50 is an element that generates power by absorbing light having, for example, a rectangular flat plate shape. In the present embodiment, the solar battery cell 50 extends along the surface direction of the solar battery module 10 and includes a plurality of solar battery cells 50. The side surfaces are arranged at a predetermined interval so that the side surfaces thereof face each other. As the solar cell 50, for example, a single crystal silicon type, a polycrystalline silicon type, an amorphous silicon type, a compound type, or a dye-sensitized type is used. Among these, the single crystal silicon type is preferable in terms of excellent power generation efficiency. In addition, these solar cells 50 have the property of absorbing visible light and generating power while transmitting ultraviolet light.

  Note that visible light is light that can be visually recognized by humans, light having a wavelength of 360 nm to 400 nm on the short wavelength side and light having a wavelength of 760 nm to 830 nm on the long wavelength side, and ultraviolet light having a wavelength of 10 nm to 400 nm. Means light.

  The solar battery cell 50 is provided with a plurality of electrodes 51 so as to protrude from the back surface side, and the power generated in the solar battery cell 50 is extracted to the outside through the electrodes 51. Has been.

  The sealing layer 60 is a layer for sealing the entire solar battery cell 50, and the first sealing material 70 disposed on the back surface side of the solar battery cell 50 and the front surface side of the solar battery cell 50. The second sealing material 80 is arranged.

As shown in FIG. 2, the first sealing material 70 is a so-called anisotropic conductive film composed of a sealing resin 71 and a filler 72 and a pigment 73 contained in the sealing resin 71. In the present embodiment, the filler 72 includes a conductive filler 72a and a nonconductive filler 72b.
The first sealing material 70 is disposed between the solar battery cell 50 and the circuit board 20, whereby the surface of the first sealing material 70 is in contact with the back surface of the solar battery cell 50 and the electrode 51. ing.

  As the sealing resin 71, a synthetic resin having a high light transmittance is used, and it is preferable to use a material having durability such as heat resistance, high temperature resistance, high humidity resistance, and weather resistance, and electrical insulation. As a material that satisfies this condition, for example, a thermoplastic synthetic resin material mainly composed of EVA (ethylene vinyl acetate copolymer) or PVB (polyvinyl butyral) having a vinyl acetate content of 20 to 30% is used. Is done. In addition, synthetic resin materials such as ethylene / (meth) acrylic acid ester copolymers and polyvinylidene fluoride may be used.

The conductive filler 72a is a particle made of an electrically conductive metal (gold, silver, platinum, nickel, copper, aluminum, zinc, brass, an alloy thereof, or the like) dispersed and mixed in the sealing resin 71. The conductive filler 72a has a role of connecting the circuit layer 22 and the electrode 51 of the solar battery cell 50 in the first sealing material 70 in the thickness direction of the first sealing material 70, that is, The first sealing material 70 has an anisotropic conductive function. The diameter of the conductive filler 72a is preferably set to be approximately the same as or slightly smaller than the thickness of the first sealing material 70. Depending on the thickness of the first sealing material 70, for example, 10 to 50 μm It is set in the range, preferably in the range of 10 μm to 20 μm.
Further, the non-conductive filler 72b is a particle having a diameter set smaller than that of the conductive filler 72a, and for example, layered silicate or zeolite is used. As the nonconductive filler 72b, particles made of metal or resin may be used.

  As the dye 73, a phosphor having a function of converting the wavelength of light incident on the dye 73 and emitting it is used. In particular, the dye 73 has a function of converting the wavelength of ultraviolet light, which is wavelength light transmitted through the solar battery cell 50, into visible light, which is wavelength light that can be absorbed by the solar battery cell 50.

  Specifically, the following phosphors can be employed as the dye 73. That is, nitride phosphor, sulfide phosphor, thiogallate phosphor, oxynitride phosphor, silicate phosphor, aluminate phosphor, YAG phosphor, rhodamine phosphor, CdSe-ZnS quantum Among various phosphors such as a nanophosphor such as a dot, it can be appropriately employed according to the wavelength band that can be absorbed by the solar battery cell 50 to be used.

For example, as shown in FIG. 3A, such a dye 73 is dispersed and arranged separately from the filler 72 in the sealing resin 71.
Further, for example, as shown in FIG. 3B, the dye 73 may be supported on the surface of the filler 72. Thus, the form in which the pigment 73 is supported on the surface of the filler 72 is easy, for example, by chemically modifying the pigment 73 on the surface of the filler 72 or by bringing the filler 72 and the pigment 73 into contact with opposite charges. Can be produced.

  Further, for example, as shown in FIG. 3C, a form in which porous particles are employed as the filler 72 and the dye 73 is supported in the pores of the porous particles may be employed. Similar to the above, such a form can be easily created by chemically modifying the dye 73 in the pores of the filler 72 or introducing the dye 73 into the holes with opposite charges on both. In addition, as the filler 72 which makes a porous particle, the nonelectroconductive filler 72b which consists of layered silicate, a zeolite, etc. as mentioned above corresponds. Further, even when the conductive filler 72a is used, a form in which the pigment 73 is supported in the conductive filler 72a can be created by using a porous metal or conductive material.

  The first sealing material 70 is configured to contain the filler 72 and the dye 73 in the sealing resin 71, whereas the second sealing material 80 is sealed without containing the filler 72 and the dye 73. It consists only of the resin 81. The second sealing material 80 is disposed between the solar battery cell 50 and the translucent base material 40, whereby the surface of the second sealing material 80 is the surface and side surface of the solar battery cell 50. Touching. As the sealing resin 81 of the second sealing material 80, the same material as the sealing resin 71 of the first sealing material 70 can be used.

Next, a method for manufacturing the solar cell module 10 will be described.
First, a metal foil is bonded onto the insulating base material 21, and the circuit layer 22 is formed by etching the metal foil, whereby the circuit board 20 is obtained. Thereafter, the back sheet 30 is bonded to the back surface of the insulating base material 21 in the circuit board 20.

  Subsequently, each member is laminated | stacked on the surface side of the circuit board 20 in order of the 1st sealing material 70, the photovoltaic cell 50, and the 2nd sealing material 80. FIG. At this time, the electrode 51 of the solar battery cell 50 is in a state of facing the circuit layer 22 with the first sealing material 70 interposed therebetween. In addition, as the 1st sealing material 70, the EVA sheet (sealing resin 71) etc. which contain the conductive filler 72a and the nonelectroconductive filler 72b, the pigment | dye 73, etc. as the filler 72, for example are used, and the 2nd sealing material 80 is used. As the above, an EVA sheet (sealing resin 81) that does not contain the filler 72 and the pigment 73 is used. Then, heat treatment is performed while applying pressure from the surface side of the second sealing material 80 using, for example, a flat plate. Thereby, the solar cell 50 is sealed by the sealing layer 60 formed by melting and integrating the sealing resin 71 of the first sealing material 70 and the sealing resin 81 of the second sealing material 80.

  Here, when pressure is applied in the thickness direction to the molten first sealing material 70 by performing the heat treatment while applying pressure as described above, the solar battery cell 50 and the circuit board 20 that are opposed to each other. The conductive filler 72a is in contact with the electrode 51 and the circuit layer 22 at a place where the facing distance is the shortest, that is, at a place where the electrode 51 of the solar battery cell 50 and the circuit layer 22 of the circuit board 20 face each other. Thus, the electrode 51 and the circuit layer 22 are electrically connected in the thickness direction of the first sealing material 70 via the conductive filler 72a. In addition, since the said conductive filler 72a is disperse-mixed in the 1st sealing material 70, the some adjacent conductive filler 72a does not contact, and a short circuit arises in the electrode 51 or the circuit layer 22. FIG. There is no.

  Then, the solar cell module 10 of this embodiment can be obtained by joining the translucent base material 40 to the surface of the second sealing material 80 in the sealing layer 60.

  According to the solar cell module 10 having such characteristics, the electrode 51 of the solar cell 50 is provided by the conductive filler 72a in the first sealing material 70 interposed between the solar cell 50 and the circuit board 20. And the circuit layer 22 of the circuit board 20 can be secured. That is, by sandwiching the first sealing material 70 between the solar battery cell 50 and the circuit board 20, the conductive filler 72 a of the first sealing material 70 contacts the electrode 51 and the circuit layer 22. Thereby, anisotropic conductivity due to the conductive filler 72 a is expressed, and the desired electrode 51 and the circuit layer 22 can be electrically connected without causing a short circuit in the electrode 51 or the circuit layer 22.

  Since the electrical connection between the electrode 51 and the circuit layer 22 can be performed simultaneously with the sealing of the solar battery cell 50 by performing the pressure heating process as described above, the mounting of the solar battery cell 50 is performed. There is no need to perform a separate process, and production efficiency can be improved.

  Further, the wavelength light that has passed through the solar cell 50 and reached the first sealing material 70, that is, ultraviolet light, is visible light that is absorbed by the solar cell 50 by entering the dye 73. Wavelength converted to light. And this visible light injects into the photovoltaic cell 50 again from the back side through the reflection by the filler 72 containing the electroconductive filler 72a and the nonelectroconductive filler 72b. Thereby, the light that has not contributed to the power generation by the solar battery cell 50 can be contributed to the power generation, and the light utilization efficiency can be improved.

  Moreover, in the photovoltaic cell 50, since the light absorption wavelength band is set in the visible light wavelength range as described above, ultraviolet light outside the wavelength range is transmitted. In this regard, in the present embodiment, the ultraviolet light transmitted through the solar battery cell 50 is converted into visible light by the pigment 73 in the first sealing material 70 and is incident on the solar battery cell 50 again through reflection by the filler 72. By doing so, it becomes possible to improve the utilization efficiency of light.

  Further, as shown in FIG. 3A, when the pigment 73 is separated from the filler 72 and dispersed in the sealing resin 71, the light incident on the first sealing material 70 is transmitted to the first sealing material 70. Wavelength conversion can be performed evenly and efficiently over the entire area. Therefore, the light use efficiency can be further improved.

  Here, when the filler 72 is dispersed and mixed in the sealing resin 71 as described above, the dispersed pigments 73 are condensed with the passage of time, resulting in unevenness in wavelength conversion of light. The light utilization efficiency may decrease. On the other hand, as shown in FIG. 3B, by supporting the pigment 73 on the surface of the filler 72, self-condensation between the pigments 73 can be avoided, and the light use efficiency can be kept high over a long period of time. it can.

  Furthermore, as shown in FIG. 3C, when the dye 73 is held in the pores of the filler 72, the dye 73 can be protected from the surroundings, so that aging can be prevented. . Further, since the electronic state of the dye 73 is stabilized, the wavelength conversion function can be prevented from being lowered, and the wavelength conversion can be reliably performed over a long period.

As mentioned above, although embodiment of this invention was described in detail, unless it deviates from the technical idea of this invention, it is not limited to these, A some design change etc. are possible.
For example, as the first sealing material 70, an adhesive containing a filler 72 and a dye 73, that is, using an anisotropic conductive adhesive, and as the second sealing material 80, an adhesive not containing the filler 72 is used. Also good. Also by this, energization with the electrode 51 of the photovoltaic cell 50 and the circuit layer 22 of the circuit board 20 can be easily ensured while securely sealing the photovoltaic cell 50.

  Furthermore, in the embodiment, the filler 72 in the first sealing material 70 includes not only the conductive filler 72a but also the nonconductive filler 72b. However, the nonconductive filler 72b is necessarily included. There is no need, for example, as shown in FIG. 4, it may be a structure containing only the conductive filler 72a. In this case, the light wavelength-converted by the pigment 73 is guided to the solar battery cell 50 through the reflection of only the conductive filler 72a. This also makes it possible to improve the light utilization efficiency.

  Moreover, when the non-conductive filler 72b is contained in the first sealing material 70, the linear expansion coefficient of the first sealing material 70 can be changed by adjusting the content. By utilizing this, the separation of the solar battery cell 50 can be prevented by setting the linear expansion coefficient of the first sealing material 70 to an intermediate value between the linear expansion coefficients of the solar battery cell 50 and the circuit board 20. .

  Further, by forming a metal film on the surface of the non-conductive filler 72b or making the refractive index of the non-conductive filler larger than that of the sealing resin 71, the reflection efficiency by the non-conductive filler 72b is improved. It is possible to further improve the use efficiency of.

DESCRIPTION OF SYMBOLS 10 Solar cell module 20 Circuit board 21 Insulating base material 22 Circuit layer 30 Back sheet 40 Translucent base material 50 Solar cell 60 Sealing layer 70 First sealing material 71 Sealing resin 72 Filler 72a Conductive filler 72b Non-conductive Filler 73 dye 80 second sealing material 81 sealing resin

Claims (6)

A circuit board having a circuit layer formed on the surface of an insulating base;
A solar battery cell disposed on the front side of the circuit board and having an electrode on the back surface;
A first sealing material interposed between the circuit board and the solar battery cell to seal the solar battery cell from the back side;
A second sealing material for sealing the solar battery cell from the surface side;
The first sealing material contains a filler and a pigment in the sealing resin,
The filler includes a conductive filler capable of electrically connecting at least the electrode and the circuit layer,
The solar cell module, wherein the dye has a function of converting wavelength light transmitted through the solar cell into wavelength light that can be absorbed by the solar cell. The wavelength light transmitted through the solar cell is ultraviolet light,
The solar cell module according to claim 1, wherein the wavelength light that can be absorbed by the solar cell is visible light.   The solar cell module according to claim 1 or 2, wherein the pigment is dispersed and mixed in the sealing resin.   The solar cell module according to claim 1 or 2, wherein the pigment is supported on a surface of the filler.   The solar cell module according to claim 1 or 2, wherein the filler is porous and the pigment is supported in pores of the filler.   The solar cell module according to any one of claims 1 to 5, wherein the insulating base material is formed by impregnating a glass fiber with an insulating resin.

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