JP4330241B2 - Solar cell module - Google Patents

Description

【００３８】
表１より、１０００時間経過後であれば、従来ＰＶＦだけを用いたものでは、初期特性が９５％を切り、ＪＩＳの規格をクリアできないのに対して、本発明の太陽電池モジュールであれば、初期特性より特性の変化率が少なく９５％以上の特性を十分に満足しており、ＪＩＳの規格はクリアしている。また、裏面部材として、積層フィルムを用いたものより良好な特性が得られている。
【００３９】
このように、この発明によれば、強化ガラスと水分との相互作用によって析出するＮａイオンの太陽電池素子への到達を抑制でき、耐湿性が向上する。
【００４０】
尚、上記した実施の形態において、封止樹脂としてＥＶＡを用いているが、シリコーン、ポリ塩化ビニル、ＰＶＢ（ポリビニルブチラール）、ポリウレタンを用いることができる。
【００４１】
上記した実施形態においては、太陽電池素子として、ＨＩＴ構造の太陽電池素子を用いた場合につき説明したが、この発明は、他の単結晶シリコンや多結晶シリコンを用いた結晶系太陽電池素子、非晶質系太陽電池素子を用いた太陽電池モジュールにも適用することができる。
【００４２】
【発明の効果】
以上説明したように、この発明によれば、表面強化ガラスから析出したナトリウムイオンを太陽電池素子まで到達するのが抑制でき、屋外における長期な使用に耐えうる高い信頼性の太陽電池モジュールを提供することができる。
【図面の簡単な説明】
【図１】表裏から光を入射させるように構成した太陽電池素子の一例を示す模式的斜視図である。
【図２】この発明の第１の実施形態に係る太陽電池モジュールの模式的断面図である。
【図３】この発明の第２の実施形態に係る太陽電池モジュールの模式的断面図である。
【図４】この発明の第３の実施形態に係る太陽電池モジュールの模式的断面図である。
【図５】従来の太陽電池モジュールの模式的断面図である。
【符号の説明】
１ 太陽電池素子
２ 表面側透光性フィルム材
３ 封止樹脂
４ 裏面側透光性フィルム材
５ スペーサ
６ 空気層[0001]
The present invention relates to a solar cell module, and is particularly suitable for use in a double-sided solar cell module that allows light to be incident from both the front and back sides by having a translucent surface member and back member. Is.
[0002]
[Prior art]
Solar cell devices that directly convert light energy into electrical energy use inexhaustible sunlight as an energy source, and are expected to be an alternative energy source to fossil energy such as oil and coal due to environmental issues, and are being put to practical use. Yes. In order to use such a solar cell device as an actual energy source, a solar cell module whose output is increased by connecting a plurality of solar cell elements electrically in series or in parallel is generally used.
[0003]
As shown in FIG. 5, the conventional solar cell module is one-sided power generation, and a plurality of solar cell elements 110... EVA (ethylene vinyl acetate) are provided between the surface tempered glass 100 and the back surface member 101. The structure is sealed with a light-transmitting and insulating resin 102.
[0004]
The solar cell element 110 is composed of single crystal silicon, polycrystalline silicon, or the like, and the solar cell elements 110 are connected in series and / or in parallel by connecting members 111 made of a metal thin plate such as a copper foil plate. The back member 101 is a laminated film in which a metal foil such as an aluminum (Al) foil is sandwiched with a plastic film in order to prevent moisture from entering from the back surface.
[0005]
[Problems to be solved by the invention]
Since a solar cell module is generally used outdoors for a long time, it needs to have excellent weather resistance as well as mechanical strength. In the structure described above, the mechanical strength is maintained by the surface strengthened glass 100. And regarding weather resistance, since the laminated film which sandwiched the metal foil with the plastic film is used as the back surface member 101, the moisture permeation from the outside is suppressed, and high power generation performance is obtained over a long period of time. However, there was still room for improvement.
[0006]
In addition, in order to effectively use the light of the solar cell element, the solar cell is configured so that light is incident from both the front and back surfaces of the solar cell element, with a transparent electrode structure not only on the light incident side electrode but also on the back side electrode. Devices have been proposed. In such a structure, a translucent member is used for the back member. When a translucent resin film is used as the back member, moisture can easily enter as compared with a laminated film in which a metal foil is sandwiched with a plastic film. In addition, it has been proposed to use a film having a low water permeability as the translucent resin film, but there is still room for improvement.
[0007]
The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a solar cell module with improved reliability by improving moisture resistance.
[0008]
[Means for Solving the Problems]
First, in order to investigate the cause of the decrease in power generation performance due to the ingress of moisture, the present inventors sandwiched an aluminum (Al) foil with PVF (polyvinyl fluoride) on the back member 101 in the structure shown in FIG. Two types of modules, a solar cell module using the laminated film and a solar cell module using only the PVF film, were prepared, and a moisture resistance test (JIS C8917) was performed on each of them. This test examines the solar cell characteristics before and after 1000 hours in a constant temperature bath maintained at 85 ° C. and a humidity of 93%, and an output value of 95% or more is defined as a pass criterion. Yes. Here, the test was carried out with the time taken in the thermostatic oven set at 1000 hours. As a result, the obtained output change rate was 99.0% when the laminated film was used for the back member, and 92.0% when the PVF film was used. And when intensively examining these two types of solar cell modules, the amount of sodium present in 1 g of the resin sealing the solar cell element is 0.3 μg / g when using a laminated film, When the PVF film was used, it was 3 μg / g, which was correlated with the rate of change in output. It was found that the power generation performance decreased as the amount of sodium in the resin increased.
[0009]
The increase in the amount of sodium is considered to be due to the presence of moisture that has entered the module. That is, when a laminated film is used for the back member, moisture enters from the outer periphery of the solar cell module. However, when a resin film is used for the back member, moisture enters even if it passes through the resin film. Therefore, the amount of moisture entering the module increases when the resin film is used as the back member.
[0010]
Then, when moisture enters the module, sodium ions precipitated from the surface glass move through the resin containing moisture to reach the surface of the solar cell element, and further diffuse to the inside of the solar cell element. In order to reduce the power generation performance, it is presumed that the power generation performance is reduced when the resin film is used on the back surface.
[0011]
Therefore, the present invention is intended to improve reliability by suppressing sodium precipitated from the surface glass from reaching the surface of the solar cell element.
[0012]
The solar cell module according to the present invention is a solar cell module which is made in consideration of the above-described matters and has surface tempered glass disposed on the surface side of a plurality of solar cell elements . It has a heterojunction formed of a crystalline silicon substrate and an amorphous silicon layer, and has a structure that allows light to enter from both the front and back surfaces, and a surface-side translucent film material on each of the surface side and the back side of the solar cell element And the back side translucent film material is disposed, and the solar cell element is resin-sealed between the front side translucent film material and the back side translucent film material, and the front side of the front side film material Further, the surface tempered glass is arranged through an air layer.
[0015]
A spacer member may be disposed between the surface tempered glass and the surface side translucent film material, and an air layer may be formed therebetween.
[0016]
The spacer member may be formed of a high thixotropic adhesive.
[0017]
By providing the air layer as described above, the solar cell element does not come into contact with the surface glass member via the EVA sealing resin or the like, so that sodium ions precipitated from the surface glass member are prevented from reaching the solar cell element. it can.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0019]
First, an example of the solar cell element 1 used in the present invention will be described with reference to FIG. FIG. 1 is a schematic perspective view showing an example of a solar cell element configured to allow light to enter from both front and back surfaces. This solar cell element has a structure in which substantially intrinsic amorphous silicon is sandwiched between a single crystal silicon substrate and an amorphous silicon layer, defects at the interface are reduced, and characteristics of the heterojunction interface are improved. (Hereinafter referred to as the HIT structure) in which the light can be incident from both the front and back surfaces.
[0020]
As shown in FIG. 1, an intrinsic amorphous silicon layer 11 is formed on an n-type single crystal silicon substrate 10, and a p-type amorphous silicon layer 12 is formed thereon. A light-receiving surface side transparent electrode 13 made of ITO or the like is provided on the entire surface of the p-type amorphous silicon layer 12, and a comb-shaped collector electrode 14 made of silver (Ag) or the like is formed on the light-receiving surface side transparent electrode 13. Has been. The back surface of the substrate 10 has a so-called BSF (Back Surface Field) structure in which an internal electric field is introduced into the back surface of the substrate. That is, a highly doped n-type amorphous silicon layer 16 is provided on the back surface side of the substrate 10 via the intrinsic amorphous silicon layer 15. A back-side transparent electrode 17 made of ITO or the like is formed on the entire surface of the highly doped n-type amorphous silicon layer 16, and a comb-shaped collecting electrode 18 made of silver (Ag) or the like is formed thereon. In this way, the back side also has a BSF structure in which an intrinsic amorphous silicon layer is sandwiched between the crystalline silicon substrate and the highly doped amorphous silicon layer, defects at the interface are reduced, and the characteristics of the heterojunction interface are improved. It has become.
[0021]
A plurality of solar cell elements 1 shown in FIG. 1 are connected in series and / or in parallel by a connection member such as a solder dip copper foil (not shown). Then, as shown in FIG. 2, EVA (between the front side translucent film member 2 and the rear side translucent film member 4 having a thickness of 0.1 to 1 mm made of PVF (polyvinyl fluoride) or the like is used. A submodule is formed by sealing with (ethylene / vinyl / acetate) resin 3.
[0022]
The sub-module is formed by stacking each member and holding it in a bag vacuumed to about 100 Pa, then heating the whole to about 150 ° C. and then crimping it from the back member side with a silicone sheet using atmospheric pressure. To do. After the EVA sheet is softened and temporarily bonded by this process, it is formed by a so-called vacuum laminating process in which the EVA sheet is held again in a constant temperature bath at about 150 ° C. for about 1 hour to cross-link the EVA. The planar size of the submodule is the same as that of the surface tempered glass 20.
[0023]
Next, a silicone resin or the like is formed on the translucent film member 2 in a portion corresponding to the gap between the solar cell elements 1 on the surface side of the surface tempered glass 20 with an area that does not prevent light from entering the solar cell element 1. A highly thixotropic adhesive is applied to form the spacer 5.
[0024]
In addition, as for the spacer 5 provided on the translucent film member 2 of the part corresponding to the gap between the solar cell elements 1... It also serves to prevent sagging due to its own weight.
[0025]
Next, the submodule and the surface tempered glass 20 are overlapped and bonded with silicon of the spacer 5. By using the spacer 5 to join the surface tempered glass 20 and the submodule, the air layer 6 is provided between the surface side of the solar cell element 1 of the submodule and the surface tempered glass 20.
[0026]
The frame 30 is attached around the solar cell module thus formed. The frame 30 is attached by fixing the periphery of the solar cell module with silicone rubber or the like, or by forming a step portion into which the solar cell module is fitted in the frame 30 in advance. You may comprise so that both may be fixed by inserting in.
[0027]
As described above, in this embodiment, the surface strengthened glass 20 having mechanical strength is provided on one surface of the solar cell module via the air layer 6. By comprising in this way, since the solar cell element 1 does not contact the surface tempered glass 20 via the EVA sealing resin 2, the sodium (Na) ion deposited from the surface tempered glass 20 reaches the solar cell element 1. Can be suppressed.
[0028]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0029]
The difference from the first embodiment described above is that, as a material for the spacer member, in addition to the highly thixotropic silicon resin spacer 5, the second spacer 7 made of a film plate such as acrylic or polycarbonate having a thickness of 1 to 5 mm is used. It was.
[0030]
Since it is the same as the said embodiment until it forms a submodule, description is abbreviate | omitted and it demonstrates from the adhesion | attachment of the surface tempered glass 20 and a submodule.
[0031]
A second spacer 7 made of a film plate made of acrylic or polycarbonate having a thickness of 1 to 5 mm is prepared. This 2nd spacer 7 is processed into the area which does not prevent the light incidence to the solar cell element 1 in the part corresponding to the clearance gap between the solar cell elements 1 .... Then, a double-sided tape is attached to the adhesive surface of the second spacer 7 or an adhesive silicon resin is applied. The second spacer 7 is disposed on the translucent film member 2 at a portion corresponding to the gap between the solar cell elements 1. The periphery of the submodule is coated with a highly thixotropic silicon resin in the same manner as in the above embodiment to form the spacer 5.
[0032]
In this case, the height of the space 6 between the submodule and the surface tempered glass 20 is determined by the thickness of the solid second spacer 7, and a space height with little variation can be formed. And the flame | frame 30 is attached to the circumference | surroundings of the solar cell module formed in this way.
[0033]
In both of the embodiments described above, the submodule and the surface glass 20 are bonded to each other and then attached to the aluminum frame 30. By attaching the frame 30, the submodule and the surface tempered glass 20 have a space. It may be configured to be fixed. Further, the structure of the frame 30 allows the submodule and the surface tempered glass 20 to be fixed with a space without providing a spacer.
[0034]
In the above-described embodiment, the submodule is formed in advance. As shown in FIG. 4, the spacer member 8 made of a high thixo material is provided on the gap between the solar cell elements 1. A sealing resin 9 such as EVA is provided in the periphery so that the back transparent film 4 and the front glass 20 are integrated, and a space 6 is provided between the surface of the solar cell element 1 and the front glass 20. It can also be configured. Also in this structure, since the solar cell element 1 does not contact the surface tempered glass 20 via the EVA sealing resin, Na ions precipitated from the surface tempered glass 20 are difficult to reach the solar cell element 1.
[0035]
Next, the solar cell module of the present invention having the above-described structure and the solar cell module having the conventional structure are prepared and the results of the moisture resistance test are shown. This test examines the characteristics of the solar cell before and after 1000 hours in a constant temperature bath maintained at 85 ° C. and 93% humidity, and the output value is determined to be 95% or more as a criterion for acceptance. Yes.
[0036]
The sample according to the present invention has the structure shown in FIG. 2, and transparent PVF films are used on the front and back sides. As a conventional example, it is the thing of the structure shown in FIG. 5, and what used only the transparent film which consists of PVF as a back surface member, and what used the laminated film which sandwiched the PVF film and aluminum foil as a back surface member. Each prepared. The thickness of the sealed EVA resin sheet was the same in all samples, and the solar cell element having a double-sided incident type HIT structure was used. The results are shown in Table 1.
[0037]
[Table 1]

[0038]
From Table 1, if it is after 1000 hours, with the conventional PVF only, the initial characteristics are less than 95%, JIS standards can not be cleared, whereas the solar cell module of the present invention, The change rate of the characteristic is smaller than the initial characteristic, and the characteristic of 95% or more is sufficiently satisfied, and the JIS standard is cleared. Moreover, the characteristic better than what used the laminated | multilayer film as a back surface member is acquired.
[0039]
Thus, according to this invention, the arrival of Na ions, which are precipitated by the interaction between the tempered glass and moisture, to the solar cell element can be suppressed, and the moisture resistance is improved.
[0040]
In the above embodiment, EVA is used as the sealing resin, but silicone, polyvinyl chloride, PVB (polyvinyl butyral), and polyurethane can be used.
[0041]
In the above-described embodiment, the case where a solar cell element having a HIT structure is used as the solar cell element has been described. However, the present invention is not limited to a crystalline solar cell element using other single crystal silicon or polycrystalline silicon, The present invention can also be applied to a solar cell module using a crystalline solar cell element.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress the sodium ions precipitated from the surface tempered glass from reaching the solar cell element, and provide a highly reliable solar cell module that can withstand long-term use outdoors. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an example of a solar cell element configured to allow light to enter from the front and back sides.
FIG. 2 is a schematic cross-sectional view of the solar cell module according to the first embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of a solar cell module according to a second embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of a solar cell module according to a third embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of a conventional solar cell module.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Solar cell element 2 Front surface side translucent film material 3 Sealing resin 4 Back surface side translucent film material 5 Spacer 6 Air layer

Claims (3)

A solar cell module in which surface tempered glass is arranged on the surface side of a plurality of solar cell elements,
The solar cell element, which has a hetero junction formed from a single crystal silicon substrate and an amorphous silicon layer, is from both sides and the light incidence structure capable,
A front-side translucent film material and a back-side translucent film material are respectively arranged on the front surface side and the back surface side of the solar cell element, and the solar cell element is interposed between the front-side translucent film material and the back-side translucent film material. While sealing the solar cell element with resin,
Wherein the surface side of the front film member, double-sided incidence type solar cell module, characterized in that a said surface strengthened glass through an air layer.   The solar cell module according to claim 1, wherein a spacer member is disposed between the surface tempered glass and the surface side translucent film material, and an air layer is formed therebetween.   The solar cell module according to claim 2, wherein the spacer member is formed of a high thixotropic adhesive.

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