JP2008160049A - Solar cell module and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable solar cell module with improved diode heat dissipation properties having a simple structure in which a terminal box is not provided, and to provide a method of manufacturing the solar cell module. <P>SOLUTION: A light-transmissive front surface component, a back surface component opposing the front surface component, a solar cell element hermetically sealed between the front surface component and the back surface component by a sealing resin material, and a diode connected to the solar cell element and of which at least one portion is provided outside of an area hermetically sealed by the sealing resin material are included. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  The solar cell module is formed by connecting a plurality of solar cell elements and encapsulating with a light-transmitting substrate and a filler mainly composed of ethylene vinyl acetate copolymer (EVA), and the connection between the solar cell elements is as follows. For example, as shown in FIG.

  FIG. 6 schematically shows a connection structure of a general solar cell module, where 1 is a solar cell element, 1a is a specific solar cell element therein, and 1b is a solar cell element group. 2 and 3 are bypass diodes, 4 is a positive output terminal of the solar cell module, 5 is a negative terminal of the solar cell module, and 6 is an intermediate output unit.

  The positive side output terminal 4 and the negative side terminal 5 of the solar cell module are respectively connected to the positive side and the negative side of the solar cell elements at both ends of the connected solar cell elements in order to connect the solar cell module and the external circuit. It is provided as follows.

Here, a technique has been proposed in which the bypass diodes 2 and 3 are disposed inside the solar cell module in a state of being covered with a filler together with the solar cell elements (see, for example, Patent Document 1).
JP 2000-164910 A

  However, according to the above-described technique, when the bypass diode generates heat, the surrounding filler may be altered by the heat and the characteristics of the solar cell element may be deteriorated. Further, the solar cell module may be deteriorated in characteristics due to stress caused by foaming of the filler.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a highly reliable solar cell module and a solar cell module with a simple structure in which a terminal box is not provided and the heat dissipation of a diode is improved. It is to provide a manufacturing method.

  The solar cell module of the present invention is hermetically sealed using a sealing resin material between a translucent surface member, a back member facing the surface member, and the front member and the back member. A solar cell element and a diode that is installed at least partly outside the region hermetically sealed with the sealing resin material and connected to the solar cell element.

  The sealing resin material is preferably an ethylene-vinyl acetate copolymer (EVA).

  Moreover, it is desirable to have a curable resin that hermetically seals the diode on the surface member.

  The curable resin is preferably made of at least one of silicon sealant, silicon rubber, ethylene propylene rubber (EPDM), and fluorine rubber.

  The curable resin preferably contains a ceramic material.

  The diode is preferably covered with a cover member. In particular, the cover member is preferably made of an insulating resin material.

  The diode is preferably installed on the surface member via a high heat dissipation material.

  The diode is preferably a bypass diode connected in parallel between the input side and the output side of the solar cell element.

  The diode is preferably a backflow prevention diode connected in series to the output side of the solar cell element.

  The backflow prevention diode is connected in series with at least one output side of the solar cell element in a parallel circuit in which a plurality of the solar cell elements are connected in parallel between the input side and the output side. It is desirable.

  Moreover, the manufacturing method of the solar cell module of the present invention includes a step of hermetically sealing a solar cell element between a surface member having translucency and a back surface member facing the surface member using a sealing resin material. And a step of installing a diode for connecting to the solar cell element outside a region at least part of which is hermetically sealed with the sealing resin material, and a curable resin for the diode. And a step of covering so as to be in contact with.

  The solar cell module of the present invention is hermetically sealed using a sealing resin material between a translucent surface member, a back member facing the surface member, and the front member and the back member. A solar cell element and a diode that is at least partially installed outside the region hermetically sealed with the sealing resin material and connected to the solar cell element. The deterioration and the foaming of the sealing resin material based on it can be suppressed, and the characteristic fall of a solar cell module can be suppressed.

  Moreover, the manufacturing method of the solar cell module of the present invention includes a step of hermetically sealing a solar cell element between a surface member having translucency and a back surface member facing the surface member using a sealing resin material. And a step of installing a diode for connecting to the solar cell element outside a region at least part of which is hermetically sealed with the sealing resin material, and a curable resin for the diode. And the step of covering so as to be in contact with the solar cell module, it is possible to suppress the deterioration and foaming of the encapsulating resin material based on the heat generation of the diode, and to manufacture a solar cell module with reduced productivity.

  In any of the inventions, a terminal box having an expensive and complicated internal shape is not required, so that the cost of the solar cell module can be reduced, and soldering work and maintenance work of the bypass diode can be facilitated. Can do.

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

≪Solar cell module≫
FIG. 1 is a diagram showing a solar cell module of the present invention, where (a) is a plan view seen from the light-receiving surface side, and (b) is a cross-sectional view taken along line XX described in (a). (C) is an expanded sectional view which shows the attachment part structure of the bypass diode formed by cut | disconnecting by the YY line | wire as described in (a).

  In FIG. 1, 9 is a surface member (translucent substrate), 10 is a solar cell element, 11 is a connection tab, 12 is an output wiring, 13 and 14 are sealing resin materials (13 is a light-receiving surface side filler, and 14 is (Back side filler), 15 is a back member, 17 is a cover member, and 18 is an output cable.

  As the translucent substrate 9, 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 translucent substrate 9 is preferably curved from the viewpoint of increasing the heat dissipation area of a bypass diode 20 described later.

  The solar cell element 10 is 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. Inside the solar cell element 10, a PN junction (not shown) 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. Further, electrodes are formed on the front and back surfaces of the solar cell element 10 by screen printing silver paste or the like, and the surface of the electrode is solder coated over almost the entire surface in order to protect it and make it easy to attach the connection tab 11. May be.

  The connection tab 11 has a thickness of about 0.1 to 1 mm, and the width is the same as the width of the electrode of the solar cell element 10 so that the connection tab 11 itself does not shade on the light receiving surface of the solar cell element 10. Less than that. Further, the length of the connection tab 11 overlaps almost all of the electrodes, and further, the connection tab 11 overlaps with the gap between predetermined solar cell elements and the back surface side electrode of the adjacent solar cell element. For example, when using a solar cell element having a polycrystalline silicon substrate with a side length of 150 mm, the connection tab 11 has a width of about 1 to 3 mm and a length of about 280 to 320 mm. The reason why the connection tab 11 overlaps almost all the electrodes of the solar cell element 10 is to reduce the electrical resistance component. The connection tab 11 is made of a highly conductive metal material such as silver, copper, or aluminum, and a copper foil material is preferable in consideration of its conductivity and ease of solder coating. Further, the connection tab 11 is solder-coated on the entire surface so that it can be easily soldered to the electrode of the solar cell element 10. This is done by dipping or plating a copper foil or the like into a solder bath to coat a solder of about 20 to 70 microns on one side.

  The output wiring 12 is for connecting the solar cell element groups linearly connected by the connection tab 11 to each other. Like the connection tab 11, the output wiring 12 is solder having a thickness of about 0.1 to 1 mm and a width of about 5 to 15 mm. Coated copper foil or the like is used.

  The light-receiving surface side filler 13 and the back surface side filler 14 protect the solar cell element 10 and the connection tab 11 and the like, and hermetically seal them to prevent performance degradation of the solar cell element and generation of rust. For example, an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) or polyvinyl butyral (hereinafter abbreviated as PVB) is preferably used, and the thickness is 0 by a T die and an extruder. A sheet formed in a sheet shape of about 4 to 1 mm is used. These are softened and fused to be integrated with other members by heating under reduced pressure with a laminating apparatus.

  Here, EVA or PVB as the light receiving surface side filler 13 is preferably used in a transparent state from the viewpoint of power generation efficiency. On the other hand, EVA or PVB used for the back surface side filler 14 may contain titanium oxide, pigment, or the like and be colored white or the like according to the surrounding installation environment where the solar cell module is installed.

  The back member 15 serves to protect the inside of the solar cell module from external impacts and to block moisture from entering. For example, a fluorine-based fluorine-based material that sandwiches an aluminum foil so as not to transmit moisture. A resin sheet, a polyethylene terephthalate (PET) sheet on which alumina or silica is deposited, and the like are used.

  The output cable 18 leads the output from the solar cell element 10 to the outside. Like the connection tab 11, the output cable 18 is a solder-coated copper foil having a thickness of about 0.1 to 1 mm and a width of about 5 to 15 mm or a diameter of 3 The lead wire etc. which coat | covered the copper twisted wire of about-5 mm with the insulating resin are used.

  Next, the bypass diode, which is a characteristic part of the present invention, will be described in detail with reference to FIGS.

<First Example>
FIG.1 (c) is sectional drawing which shows the attachment part structure of the bypass diode based on this invention. In FIG.1 (c), 20 is a bypass diode, 21 is a connection terminal of a bypass diode, 22 shows curable resin.

  The bypass diode 20 is connected between the output wirings 12 by soldering or the like so as to be opposite to the diode polarity of the solar cell element 10. The shape of the bypass diode 20 is often flat or cylindrical, but there is no special rule, and the connection terminal 21 extends outside the bypass diode 20 so that the connection to the output wiring 12 is easy. desirable. The rated current of the bypass diode 20 may be optimally determined in consideration of the size of the solar cell elements of the solar cell module to be used, the number in series, and the like.

  For example, in the solar cell module provided with the bypass diode 20 as shown in FIG. 6, when all of the solar cell elements 1 are exposed to light, the bypass diode 20 connected in the reverse direction has a current. Does not flow.

  However, when a shadow is generated on a specific solar cell element 1a and power generation becomes insufficient, the solar cell element 1a becomes a resistor and generates heat (a so-called hot spot phenomenon). Since a potential difference between the product of the resistance value and the flowing current is generated in the electrode, the voltage across the bypass diode 20 is reversed as compared with the normal state, and the current flows through the bypass diode 20 so that a shadowed solar cell element is generated. The current flowing through 1a is reduced, the heat generation of solar cell element 1a is suppressed, and the deterioration of characteristics of solar cell element 1a can be suppressed.

  In this way, by disposing the bypass diode 20 on the surface member 9 and outside the sealing resin materials 13 and 14, the alteration and foaming of the sealing resin materials 13 and 14 based on the heat generated by the bypass diode 20 is suppressed. Thus, it is possible to manufacture a solar cell module that suppresses the damage of the bypass diode 20 and the deterioration of the characteristics of the solar cell element 1 with high productivity.

  Further, since a terminal box having an expensive and complicated internal shape is not required, the cost of the solar cell module can be reduced, and soldering work and maintenance work of the bypass diode 20 can be facilitated.

  The curable resin 22 is in close contact with the bypass diode 20 and the translucent substrate 9 and exhibits moisture resistance and thermal conductivity, and a highly fluid elastic body that can be cured under predetermined conditions is used. desirable. For example, silicon sealant, silicon rubber, ethylene propylene rubber (EPDM), fluorine rubber, etc. are preferably used. Moreover, the thing which does not change a physical property or a shape with respect to the outdoor use over the long term of a solar cell module is preferable.

  This curable resin 22 contains ceramic particles such as alumina (thermal conductivity 400 × 10 −4 cal / cm · sec · ° C.) and zirconia (thermal conductivity 70 × 10 −4 cal / cm · sec · ° C.). The thermal conductivity can be improved without impairing the insulating property of the curable resin 22.

  As for the size and content of the ceramic particles, in the tests repeatedly conducted by the inventors, the diameter of the ceramic particles is preferably 0.1 mm or more and 1.2 mm or less. The weight ratio is desirably 5% or more and 40% or less. If the ceramic particle size is 0.1 mm or more, a great effect on heat conduction is obtained regardless of the content, and if it is 1.2 mm or less, the adhesion rate of the resin can be improved. If the content is 5% or more, a great effect on heat conduction is obtained, and if it is 40% or less, the adhesion rate of the resin can be improved.

  The cover member 17 is provided for protecting the bypass diode 20 and the curable resin 22 and the like therein from an impact such as wind or lightning, and for radiating heat generated by the bypass diode 20. The cover member 17 can be made of a metal such as aluminum or stainless steel, or an insulating resin material such as polypropylene or epoxy resin. However, even when an external voltage is applied due to electric leakage or lightning, the bypass diode 20 can be Since it can protect, it is desirable to consist of insulating resin. The shape of the cover member 17 may be determined according to the size and shape of the bypass diode 20.

<Second Example>
FIG. 2 is an enlarged cross-sectional view showing another embodiment of the attachment structure of the bypass diode in the solar cell module of the present invention.

  The high heat dissipating material (heat dissipating plate) 24 is composed of a flat plate made of a metal such as aluminum, copper, brass or stainless steel having a thickness of about 0.2 to 0.5 mm and a length and width of about 20 to 50 mm. Solder coating may be used to protect the surface from rust. Needless to say, the above-described alumina and zirconia can also be used as the high heat dissipation material according to the present invention.

  The adhesive 25 is an epoxy or acrylic adhesive, and may contain metal powder such as copper in order to improve thermal conductivity.

  As shown in FIG. 2, the attachment part of the bypass diode 20 is applied to the main surface of the heat sink 24 with an adhesive 25 with a brush or the like, and is attached to the position of the translucent substrate 9 on which the bypass diode 20 is placed. wear. Thereafter, the bypass diode 20 is placed on the heat sink 24 and connected to the output wiring 12 as described above.

  In this way, by placing the bypass diode 20 on the portion of the translucent substrate 9 without the filler via the heat sink 24, a solar cell element with insufficient power generation occurs, and the bypass diode 20 When heat is generated, heat can be conducted to a wider portion of the light-transmitting substrate 9, and heat dissipation can be improved.

  Next, in addition to the above-described bypass diode, the effect of the present invention is achieved even in the case of a solar cell module using a backflow prevention diode. This will be described in detail below with reference to FIGS.

<Third embodiment>
FIG. 4 is a plan view showing a third embodiment of the solar cell module according to the present invention. FIG. 5 schematically shows FIG. In this solar cell module, a solar cell element group A and a solar cell element group B in which a plurality of solar cell elements are connected in series with each other are arranged on the same translucent substrate 9, and the solar cell element group A and the solar cell module The battery element group B is connected in parallel to constitute a parallel circuit. Between the solar cell element group A and the solar cell element group B, a cover member 17 containing a backflow prevention diode 30 is disposed.

  The backflow prevention diode 30 is configured so that when a potential difference occurs between one solar cell element group and another solar cell element group connected in parallel, the lower potential of the solar cell element group having the higher potential is reduced. It is provided to prevent a current from flowing into the solar cell element group, and is connected to the connected solar cell element group by soldering or the like in the forward direction.

  In particular, the backflow prevention diode 30 has a higher temperature than the bypass diode 20 described above because the current continues to flow during power generation in the solar cell groups A and B, and the above-described alteration of the filler, foaming and backflow prevention diode. 30 characteristic deterioration is likely to occur.

  Therefore, the backflow prevention diode 30 and the fillers 13 and 14 are not in direct contact with each other by hermetically sealing the backflow prevention diode 30 with the curable resin and the translucent substrate outside the filler as described above. It becomes possible to improve heat dissipation and to suppress the quality change and foaming of the fillers 13 and 14. Also, soldering work and maintenance work for the backflow prevention diode 30 are easier than when the terminal box is used.

  Further, as with the bypass diode 20 described above, if ceramic particles such as alumina or zirconia are included in the curable resin embedding the backflow prevention diode 30, the thermal conductivity is improved without impairing the insulating properties of the curable resin. Because it can be made desirable. Further, it is desirable to provide the cover member 17 in order to protect the backflow prevention diode 30 and the curable resin from an impact such as wind or lightning strike.

  Further, the backflow prevention diode 30 is placed on a portion of the translucent substrate 9 that is not filled with a heat sink, so that when the backflow prevention diode 30 generates heat, a wider portion of the translucent substrate 9 is placed. Heat can be conducted and heat dissipation can be improved.

  In the above-described third embodiment, the solar cell module in which the solar cell element groups are connected in parallel has been described as an example. However, in the case where a solar cell array is configured by connecting solar cell modules formed of series circuits in parallel. The solar cell modules may be connected in parallel through the backflow prevention diode 30 according to the present invention.

≪Solar cell module manufacturing method≫
Next, a method for manufacturing a solar cell module according to the present invention will be described.

  FIG. 3 is a cross-sectional view for explaining the method for manufacturing the solar cell module of the present invention.

  First, as shown in FIG. 3A, the light receiving surface side filler 13 is placed on the translucent substrate 9, and the solar cell element 10 to which the connection tab and the output cable 18 are connected is placed thereon. Furthermore, the back surface side filler 14 and the back surface sheet 15 are laminated | stacked in order on it. At this time, the output wiring 12 extends to portions outside the light receiving surface side filler 13 and the back surface side filler 14 where the bypass diode 20 is disposed. When this is set in a laminator and heated at 100 to 200 ° C. under reduced pressure, for example, for 15 minutes to 1 hour, these are integrated and a solar cell panel part is completed.

  Next, as shown in FIG. 3B, the connection terminals 21 of the bypass diode 20 and the backflow prevention diode 30 are connected to the output wiring 12 of the solar cell panel portion by soldering or the like.

  Then, as shown in FIG. 3C, a cover member 17 in which a predetermined amount of the above-described curable resin 22 is previously placed is covered so as to cover the bypass diode 20 and the backflow prevention diode 30.

  As described above, the solar cell module according to the present invention is manufactured.

  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 solder used for soldering can be implemented by other lead-free solder such as tin-lead eutectic solder.

It is a figure which shows the solar cell module of this invention, (a) is the top view seen from the light-receiving surface side, (b) is a figure which shows the cross-sectional structure formed by cut | disconnecting by the XX line as described in (a). (C) is a figure which shows the expanded cross-section which shows the attachment part structure of the bypass diode formed by cut | disconnecting by the YY line | wire as described in (a). It is a structural diagram which shows the expanded cross section which shows the other Example of the attachment part structure of the bypass diode in the solar cell module of this invention. It is structural drawing which shows the cross section for demonstrating the manufacturing method of the solar cell module of this invention. It is a top view which shows the 3rd Example of this invention. It is a top view which shows typically the 3rd Example of this invention. It is a top view which shows typically the connection structure of a general solar cell module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Solar cell element 1a; One specific solar cell element 1b, A, B; Solar cell element group 2, 3, 20; Bypass diode 3; Bypass diode 4; Plus side output terminal 5; Intermediate output section 9; surface member (translucent substrate)
10; solar cell element 11; connection tab 12; output wiring 13; light receiving surface side filler 14; back surface side filler 15; back surface member 17; cover members 17a to 17f: cover members 17g and 17h provided in the bypass diode: Cover member 18 provided in backflow prevention diode; output cable 20; bypass diode 21; bypass diode connection terminal 22; curable resin 24; high heat dissipation material (heat dissipation plate)
25; Adhesive 30; Backflow prevention diode

Claims (12)

A surface member having translucency;
A back member facing the front member;
A solar cell element hermetically sealed using a sealing resin material between the front surface member and the back surface member,
A solar cell module comprising: a diode that is installed outside the region hermetically sealed by the sealing resin material and connected to the solar cell element.   The solar cell module according to claim 1, wherein the sealing resin material is an ethylene-vinyl acetate copolymer (EVA).   The solar cell module according to claim 1, further comprising a curable resin that hermetically seals the diode on the surface member.   The solar cell module according to claim 3, wherein the curable resin is made of at least one of silicon sealant, silicon rubber, ethylene propylene rubber (EPDM), and fluorine rubber.   The solar cell module according to claim 3 or 4, wherein the curable resin contains a ceramic material.   The solar cell module according to any one of claims 1 to 5, wherein the diode is covered with a cover member.   The solar cell module according to claim 6, wherein the cover member is made of an insulating resin material.   The solar cell module according to claim 1, wherein the diode is installed on the surface member via a high heat dissipation material.   The solar cell module according to any one of claims 1 to 8, wherein the diode is a bypass diode connected in parallel between an input side and an output side of the solar cell element.   The solar cell module according to any one of claims 1 to 8, wherein the diode is a backflow prevention diode connected in series to an output side of the solar cell element.   The backflow prevention diode is connected in series with at least one output side of the solar cell element in a parallel circuit in which a plurality of the solar cell elements are connected in parallel between the input side and the output side. The solar cell module according to claim 10. A step of hermetically sealing the solar cell element using a sealing resin material between the translucent surface member and the back surface member facing the surface member;
A step of installing a diode for connecting to the solar cell element outside a region at least partially hermetically sealed with the sealing resin material;
And a step of covering the diode with a curable resin so as to be in contact with the diode.

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