JP2006060028A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a space is prone to arise between a solar cell module and a lead wire arranged on its underside during lamination or bridging and air bubbles are generated and are prone to remain in sealing material of the solar cell module, since the underside of the solar cell module has large asperities and the lead wire can not easily respond to the asperities because it is coated with insulating material. <P>SOLUTION: The solar cell module has a translucent substrate, a filling material on the light receiving surface side, several solar cell elements electrically connected by connection tabs, the filling material on the back side and a protective material of the underside which are layered in sequence. At the same time, the lead wire for getting out the electric output of the solar cell elements is placed on the underside of the solar cell elements and is further taken out to the underside of the protective material of the underside through a slit or a hole formed in the protective material of the underside. In this case, at least a part of the lead wire which is in contact with the underside of the solar cell elements is coated with adhesive agent or joining material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solar cell module, and more particularly to a solar cell module with improved reliability by improving the wiring material inside the solar cell module.

  Solar cell elements are often manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate. For this reason, a solar cell element is weak to a physical impact, and when a solar cell element is attached outdoors, it is necessary to protect this from rain. Further, since one solar cell element has a small electrical output, it is necessary to use a plurality of solar cell elements that are electrically connected in series or in parallel.

  For this reason, usually a plurality of solar cell elements are connected in series and parallel, and the plurality of connected solar cell elements are sealed with a filler between the translucent substrate and the back surface protective material, and the solar cell module is It is usually made.

  FIG. 5 shows an example of the connection state of solar cell elements inside the solar cell module. FIG. 5 shows four solar cell elements connected in series with each other, and two solar cell elements connected in series in this way, and further connected in series.

  In FIG. 5, 1 is a solar cell element, 2 is a connection tab, 3 is a lateral wiring, 4 is a coupling wiring, and 5 is a lead wire.

  The solar cell element 1 is manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate as described above, and electrodes are provided on the light receiving surface side and the back surface side thereof. The connection tab 2 is attached to the electrode of the solar cell element 1 by soldering or the like in order to connect the solar cell elements 1 in series or in parallel. The horizontal wiring 3 further connects the linearly connected solar cell elements in the horizontal direction. In a solar cell module, generally, as shown in FIG. 5, a predetermined number of solar cell elements 1 are connected by connection tabs 2, and a predetermined number of them are connected by lateral wiring 3.

  The joint wiring 4 connects the connection tabs connected to the electrodes of the same polarity of the solar cell elements at both ends of the connected solar cell elements 1. In many cases, both the lateral wiring 3 and the coupling wiring 4 are used by cutting the entire surface of a copper foil having a width of about 3 to 8 mm into a predetermined length.

  The lead wire 5 transmits electric power generated in the solar cell element 1 to a terminal box (not shown) provided on the back surface of the back surface protective material of the solar cell module, and one end thereof is soldered to the coupling wiring 4 or the like. The other end is taken out to the back side of the back surface protection material through a slit provided in the back surface protection material, and this lead wire is connected to a terminal in a terminal box formed on the back surface protection material. Yes.

Here, in many cases, the lead wire 5 is a copper foil having a width of about 3 to 8 mm, which is solder-coated on the entire surface and cut into a predetermined length. The position of the lead wire 5 is as shown in FIG. Since it arrange | positions at the back surface side of a battery element, it coat | covers with the insulating material except the connection part of the both ends so that it may not short-circuit with the back surface side electrode and the connection tab 2 of the solar cell element 1. FIG. (See Patent Document 1)
As described above, a plurality of solar cell elements connected by connection tabs, lateral wirings and coupling wirings are bonded between a translucent substrate such as glass and a back surface protective material with an ethylene-vinyl acetate copolymer (hereinafter referred to as ethylene). -Vinyl acetate copolymer is abbreviated to EVA from above and below, and these are heated and pressurized under reduced pressure by a laminating apparatus, so that EVA etc. are fused and other Integrate with members.

  Further, the sealing material is cross-linked in the integrated panel in a cross-linking furnace.

Prior art document information related to the invention of this application includes the following.
Japanese Patent Laid-Open No. 9-326497

  However, when EVA or the like is used for the above-mentioned light receiving surface side filler and back surface side filler, when the temperature is rapidly increased or maintained at a higher temperature in order to perform crosslinking in a short time at the time of lamination or crosslinking In addition, the decomposition rate of the organic peroxide contained in EVA as a crosslinking agent is increased, and the generated decomposition gas remains as bubbles without being completely degassed from the panel portion of the solar cell module.

  Such residual bubbles deteriorate the appearance of the solar cell module and also reduce the long-term reliability of the solar cell module.

  When there is a slight space between the members of the panel portion of the solar cell module, the bubbles remain and the gas generated in the vicinity is taken into this space and grows, generating bubbles and remaining. It has been understood through experiments by the present inventors that it is easy to do this.

  The back surface side of the solar cell element 1 has large unevenness due to the presence of electrodes and connection tabs 2, and the lead wire 5 is covered with an insulating material so that it is difficult to follow the unevenness. There is a problem that a space is easily formed between the lead wire 5 and the disposed lead wire at the time of lamination or cross-linking, and bubbles as described above are easily generated and remain.

  The present invention has been made in view of the above problems, and its purpose is to prevent a space from being formed between the solar cell element 1 and the lead wire 5 disposed on the back side thereof during lamination or crosslinking. Therefore, it is an object of the present invention to provide a solar cell module which has no appearance of bubbles and does not remain, has a good appearance, and has improved long-term reliability.

  In the solar cell module of the present invention, a translucent substrate, a light receiving surface side filler, a plurality of solar cell elements electrically connected by connection tabs, a back surface side filler, and a back surface protective material are stacked. And a lead wire for taking out the electrical output of the solar cell element is disposed on the back surface side of the solar cell element, and further, the back surface through a slit or hole formed on the back surface protection material In the solar cell module, the adhesive is applied to at least a portion of the lead wire in contact with the back surface side of the solar cell element.

  Moreover, as for the other solar cell module of this invention, it is desirable that the said back surface side filler is an ethylene vinyl acetate copolymer (EVA).

  According to the solar cell module of the present invention, the translucent substrate, the light receiving surface side filler, the plurality of solar cell elements electrically connected by the connection tabs, the back surface side filler, and the back surface protective material. It arranges sequentially so that it may overlap, and arranges the lead wire for taking out the electric output of the solar cell element on the back side of the solar cell element, and further through the slit or hole formed on the back surface protection material It is a solar cell module that is taken out on the back side of the back surface protective material, and by applying an adhesive or an adhesive to at least a portion of the lead wire that contacts the back side of the solar cell element, the back surface of the solar cell element With the adhesive or adhesive applied to the surface of the insulation of the lead wire, the lead wire is in contact with the rugged portion even once due to pressing during lamination. Since there will be no separation between the solar cell element and the lead wire, there will be no generation of bubbles or residue during lamination or crosslinking, and the solar cell module will have a good appearance and solar cell module The long-term reliability of can also be improved.

  Further, according to another solar cell module of the present invention, the back side filler is made of an ethylene vinyl acetate copolymer (EVA), so that EVA is more fillable than other materials such as PVB. Is excellent, and bubbles can be easily generated in the space, so that the above-described effect can be ensured.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a view showing a state in which solar cell elements are connected in series using a connection tab during the production of the solar cell module according to the present invention.

  In FIG. 1, 21a and 21b are solar cell elements, 22a and 22b are connection tabs, 23 is a light receiving surface side bus bar electrode of the solar cell element, and 24 is a finger electrode.

  The solar cell elements 21a and 21b are made of, for example, single crystal silicon or polycrystalline silicon having a thickness of about 0.3 to 0.4 mm and a size of about 150 mm square. Inside the solar cell elements 21a and 21b, a PN junction is formed in which a P layer containing a large amount of P-type impurities such as boron and an N layer containing a large amount of N-type impurities such as phosphorus are in contact.

  The bus bar electrode 23 and the finger electrode 24 are formed by screen-printing silver paste or the like, and the surface of the bus bar electrode 23 is solder-coated on almost the entire surface in order to easily protect and connect the connection tab. A large number of finger electrodes 24 having a width of about 0.1 to 0.2 mm are formed in parallel with the sides of the solar cell elements to collect photogenerated carriers. Further, the bus bar electrode 23 collects the collected carriers and has a width of about 2 mm so as to attach a connection tab, and is formed about two to three so as to intersect the finger electrode 24 perpendicularly. Such bus bar electrodes 23 and finger electrodes 24 are similarly formed on the back surfaces of the solar cell elements 21a and 21b.

  For the connection tabs 22a and 22b, a strip-shaped solar cell element connection wiring material made of copper foil is coated with solder on the entire surface thereof by solder plating or dipping of about 20 to 70 μm on one side. The widths of the connection tabs 22a and 22b are set to be equal to or less than the width of the bus bar electrode 23 so that the connection tabs 22a and 22b themselves do not shade the light receiving surface of the solar cell element when soldering. The lengths of the connection tabs 22a and 22b overlap almost all of the bus bar electrodes 23, and further overlap the non-light-receiving surface bus bar electrodes (not shown) of the adjacent solar cell elements. When a general 150 mm square polycrystalline silicon solar cell element is used, the connection tabs 22a and 22b have a width of about 1 to 3 mm and a length of about 160 to 250 mm. The reason why the connection tabs 22a and 22b overlap almost all of the light receiving surface side bus bar electrode 23 is to reduce the resistance component of the solar cell element.

  A method of connecting the bus bar electrode 23 of the solar cell element 21a and the connection tab 22a by soldering is as follows.

  First, the connection tab 22a is disposed on the bus bar electrode 23 of the solar cell element 21a. While holding the connection tab 22a with a pressing pin, hot air is blown to melt and connect the solder of both the bus bar electrode 23 of the solar cell element 21a and the connection tab 22a.

  Further, the other end of the connection tab 22a is arranged on the bus bar electrode on the back surface side of the other solar cell element 21b, and the solder is similarly melted and connected. At this time, the distance between the solar cell elements 21a and 21b is about 1 to 5 mm.

  FIGS. 2A and 2B show lead wires used in the solar cell module according to the present invention. FIG. 2 (a) shows the appearance of the lead wire according to the present invention, and FIG. 2 (b) shows its cross section.

  2A and 2B, 20 is a lead wire, 25 is an insulating material, 26 is an attachment portion at both ends of the conductive material, 27 is an applied adhesive or adhesive, and 28 is a conductive material.

  The insulating material 25 of the lead wire 20 is made of a stable material that does not change its shape and insulation when the solar cell module is mounted outdoors for 10 to 20 years. For example, a polyethylene terephthalate (PET) film is used. Is done. As the conductive material 28 of the lead wire 20, a copper foil having a width of about 3 to 8 mm and a surface coated with about 20 to 70 μm on one side by plating or dipping is cut into a predetermined length in many cases. .

  In the conductive material 28, a pressure-sensitive adhesive or adhesive for coating is applied to the surface of the insulating material 25 that contacts the conductive material 28, and the conductive material is arranged on the coated surface, and the insulating material 25 is bent so that it is folded. The surface of the conductive material 28 is covered with the insulating material 25 as shown in FIG. 2B. As a result, the conductive material 28 is insulated by the insulating material 25 leaving the attachment portions 26 at both ends thereof. The attachment portions 26 at both ends of the lead wire 20 are portions without an insulating material, which are provided about 1 to 3 cm in order to be connected to the terminals in the coupling wiring or the terminal box by soldering or the like.

  Furthermore, the lead wire 20 according to the present invention is characterized in that an adhesive or an adhesive 27 is applied to at least a portion of the surface of the insulating material that contacts the back side of the solar cell element when the lead wire 20 is attached.

  These adhesives or adhesives 27 are acrylic adhesives, silicone adhesives, EVA adhesives, epoxy adhesives, urethane adhesives, acrylic adhesives in consideration of heat resistance and long-term stability. Etc. can be used.

  FIG. 3 shows an example of a state in which a lead wire is attached to the coupling wiring of solar cell elements at one end of a plurality of solar cell elements connected in series according to the present invention.

  In FIG. 3, reference numerals 20, 21a, 21b, 22a, 22b, 25 and 26 are the same as in FIG. 1 and FIGS. 2A and 2B, 20 is a lead wire, 21a and 21b are solar cell elements, and 22a and 22b are connected. Tabs, 25 are insulating materials, 26 are attachment portions at both ends of the conductive material, 30 is a joint wiring, and 31 is a portion where the lead wire 20 is in contact with the solar cell element 21b.

  The coupling wiring 30 connects the connection tabs connected to the electrodes of the same polarity of the solar cell element at one end of the solar cell element 21b, and has a predetermined length obtained by solder-coating the entire surface of a copper foil having a width of about 3 to 8 mm. It is often used after cutting.

  The attachment portion 26 at one end of the above-described lead wire 20 is attached to the coupling wiring 30 by soldering or the like. The attachment position is such that the other end of the lead wire 20 is located at a position where a terminal box for leading electrical output to an external circuit is attached.

  The other end of the lead wire 20 is taken out to the back side of the back surface protection material through a slit or hole provided in the back surface protection material of the solar cell module, and this lead wire is taken into a terminal box formed on the back surface protection material. Connect to the terminal.

  Moreover, since the lead wire 20 is arrange | positioned in the back surface side of the solar cell element 2b so that the light which injects into a solar cell element may not be interrupted, the back surface of the lead wire 20 and the solar cell element 21b is contacting partially. Become. Since the adhesive or adhesive 27 is applied in advance to the portion 31 where the lead wire 20 is in contact with the solar cell element 21b as described above, it is applied to the back surface of the solar cell element 21b when pressed in a laminating process or the like. Even if there is unevenness such as an electrode, it does not stick or adhere, and there is no space in this part. As a result, there is no generation or residual of bubbles in lamination or cross-linking, so that the appearance of the solar cell module is improved and the long-term reliability of the solar cell module is improved.

  Note that the portion to which the pressure-sensitive adhesive or adhesive is applied may be at least applied to the portion 31 where the lead wire 20 is in contact with the solar cell element, but is larger than that portion in consideration of positioning errors and the like. There is no problem even on the entire surface of one side of the lead wire on the solar cell element side.

  FIG. 4 is a diagram showing an example of the structure of the panel portion of the solar cell module according to the present invention.

  In FIG. 4, 41 is a translucent board | substrate, 42 is a light-receiving surface side filler, 43 is a solar cell element, 44 is a back surface side filler, 45 is a back surface protection material, 46 is a connection tab, 47 shows a lead wire.

  Hereinafter, each member will be described.

  As the translucent substrate 41, a substrate made of glass or polycarbonate resin is used. As for the glass plate, white plate glass, tempered glass, double tempered glass, heat ray reflective glass and the like are used, but generally white plate tempered glass having a thickness of about 3 mm to 5 mm is used. On the other hand, when a substrate made of a synthetic resin such as polycarbonate resin is used, a substrate having a thickness of about 5 mm is often used.

  The light-receiving surface side filler 42 and the back surface side filler 44 are made of an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) or polyvinyl butyral (PVB), and have a thickness of about 0.4 to 1 mm by a T die and an extruder. The one formed into a sheet shape is used. These are heated and pressed under reduced pressure by a laminating apparatus, so that they are softened and fused to be integrated with other members.

  EVA and PVB may be colored white or the like by containing titanium oxide, pigment, or the like. However, in the light-receiving surface side filler 42 of the solar cell module according to the present invention, it enters the solar cell element 43 when colored. Transparent because the amount of light decreases and power generation efficiency decreases.

  Moreover, EVA or PVB used for the back surface side filler 44 may be transparent, or may contain titanium oxide, a pigment, or the like and be colored white or the like according to the surrounding installation environment where the solar cell module is installed.

  Furthermore, the solar cell element 43 is made of a single crystal silicon or a polycrystalline silicon substrate having a thickness of about 0.3 to 0.4 mm as described above.

  As described in detail above, the connection tab 46 is a copper foil or the like subjected to solder coating.

  The back surface protective material 45 is made of a weather-resistant fluorine-based resin sheet sandwiched with an aluminum foil, a polyethylene terephthalate (PET) sheet deposited with alumina, or silica so as not to transmit moisture. In addition, a slit or hole is provided at a predetermined position of the back material 45, and a lead wire 47 is previously drawn out from the slit or hole to the surface of the back material using tweezers or the like.

  As described above, the lead wire 47 is covered with an insulating material except for the attachment portion, and when attached, an adhesive or adhesive is applied to at least a portion of the surface of the insulation material that contacts the back surface side of the solar cell element. It has been applied.

  Next, a method for manufacturing a solar cell module will be described.

  In manufacturing the solar cell module, the light receiving surface side filler 42, the solar cell element 43 connected to the connection tab 46 and the lead wire 47 on the translucent substrate 41, and the back surface side filler 44, back surface protection thereon. The materials 45 are sequentially stacked. In such a state, they are set in a laminator, and are heated at 100 to 200 ° C., for example, for 15 minutes to 1 hour while being pressurized under reduced pressure, so that they are integrated. Further, if the crosslinking is insufficient, heating is performed at 100 to 200 ° C. for a necessary time in a crosslinking furnace.

  EVA is superior in filling properties compared to other materials such as PVB. Since bubbles are easily generated in the space portion, the above-mentioned effect can be ensured by making the back surface side filler 44 according to the present invention with EVA having excellent filling properties. For this reason, it is desirable that the back surface side filler 44 according to the present invention is made of EVA.

  Furthermore, a module frame and a terminal box were attached to each side of the solar cell panel unit in which the above-described translucent substrate, light receiving surface side filler, solar cell element, back surface side filler, and back surface protective material were integrated by lamination. Thereafter, each corner portion of the module frame is screwed to complete the solar cell module.

  This module frame is often made of aluminum or resin in consideration of the strength and cost required for the solar cell panel. When it is made of aluminum, it is often made by extruding aluminum, and its surface is often subjected to alumite treatment or clear coating.

  In addition, this invention is not limited to the said embodiment, Many corrections and changes can be added within the scope of the present invention. For example, the solar cell element is not limited to a crystalline solar cell such as single crystal or polycrystalline silicon, but can also be applied to a thin film solar cell and further coated with a connection tab or an electrode of the solar cell element. The solder can be applied to lead-free solder in addition to eutectic solder containing lead, etc., and further can be applied to a solar cell element without solder coating.

The state which connected the solar cell elements which concern on this invention in series using the connection tab is shown. (A) The external appearance of the lead wire which concerns on this invention is shown.

(B) The cross section of the lead wire which concerns on this invention is shown.
FIG. 3 shows an example of a state in which a lead wire is attached to the coupling wiring of solar cell elements at one end of a plurality of solar cell elements connected in series according to the present invention. An example of the structure of the panel part of the solar cell module which concerns on this invention is shown. An example of the connection state of the solar cell element inside a solar cell module is shown.

Explanation of symbols

1: Solar cell element 2: Connection tab 3; Lateral wiring 4: Coupling wiring 5: Lead wire 20, 47: Lead wires 21a, 21b, 43: Solar cell elements 22a, 22b, 46: Connection tab 23: Bus bar electrode 24 : Finger electrode 25: Insulating material 26: Attachment portion 27 at both ends of the conductive material 27: Applied adhesive or adhesive 28: Conductive material 30: Bonded wiring 31: Portion where the lead wire contacts the solar cell element 41: Translucent substrate 42: Light receiving surface side filler 44: Back surface side filler 45: Back surface protective material

Claims (2)

A transparent substrate, a light receiving surface side filler, a plurality of solar cell elements electrically connected by a connection tab, a back surface side filler, and a back surface protective material are sequentially disposed so as to overlap, and A lead wire for taking out the electrical output of the solar cell element is arranged on the back side of the solar cell element, and is further taken out to the back side of the back side protective material through a slit or hole formed on the back side protective material. A solar cell module, wherein an adhesive or an adhesive is applied to at least a portion of the lead wire that contacts the back surface side of the solar cell element. The solar cell module according to claim 1, wherein the back surface side filler is made of an ethylene vinyl acetate copolymer (EVA).

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