JP4738147B2 - Solar cell module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell module in which a plurality of solar cell elements are connected by a connection tab and a method for manufacturing the solar cell module, and more particularly to a solar cell module having improved bonding strength between the solar cell element and the connection tab and a method for manufacturing the solar cell module. It is.

  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 electric output, it is necessary to use a plurality of solar cell elements that are electrically connected in series or in parallel.

  For this reason, the wiring material is cut to an appropriate length (hereinafter, this wiring material is cut to an appropriate length is called a connection tab), and a plurality of solar cell elements are connected in series and parallel using this, Usually, the solar cell module is formed by arranging the connected solar cell elements between a light-transmitting substrate and a back sheet in a state of being covered with a filler.

  FIG. 1 is a plan view of a light receiving surface side of a typical solar cell module, FIG. 2 is a partially exploded cross-sectional view of the module, and FIG. 3 is a plan view of a state where a connection tab is soldered to a solar cell element. FIG.

  In the figure, 1 is a translucent light receiving surface side member, 2 is a solar cell element, 3 is a wiring member, 4 is a module frame, and 5 is a solar cell element connected by the wiring member. Group (solar cell element string), 6 is a lateral wiring member, 7 is a back surface side member, 8 is a light receiving surface side filler, and 9 is a back surface side filler.

  As the translucent substrate 1 that is the translucent light receiving surface side member, a substrate made of glass, polycarbonate resin, or the like is used.

  The light receiving surface side filler 8 and the back surface side filler 9 are made of an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) or polyvinyl butyral (PVB), and are formed into a sheet shape having a thickness of about 0.4 to 1 mm. Softened and fused.

  For the back side member 7, for example, a sheet having weather resistance and moisture resistance is used.

  The solar cell element 2 includes, for example, a PN bonded silicon substrate, a light receiving surface side electrode, and a back surface side electrode. Examples of the electrode on the light receiving surface side include a bus bar electrode 21 and finger electrodes 22, which are formed by screen printing a silver paste or the like. The surface of the bus bar electrode 21 is also a region where the protection and connection tabs 3 are soldered, and may be solder coated over almost the entire surface. Similarly, bus bar electrodes, finger electrodes, and the like are formed on the back surface (non-light receiving surface) side of the solar cell element 2.

  The connection tab 3 is for electrically connecting the solar cell elements 2 to each other, and is formed in a strip shape obtained by applying a solder coat to the surface of a copper foil or the like and cutting it to an appropriate length. Then, one end side of the connection tab 3 is soldered to the bus bar electrode on the light receiving surface side of one adjacent solar cell element, and the other end side is soldered to the bus bar electrode on the back side of the other solar cell element. It was attached.

When attaching the connection tab 3 to the bus bar electrode 21 of the solar cell element 1, the connection tab 3 is positioned on the bus bar electrode 21 of the solar cell element 2 as shown in FIG. Is pushed down, and the connection tab 3 is pressed against the bus bar electrode 21. In this state, hot air of about 400 to 500 ° C. is blown from the nozzle 85 to the connection tab 3 for about 1 or 2 seconds to melt the solder coated on the surface of the connection tab 3 or the solder coated on the surface of the bus bar electrode 21. Then, both are joined. Thereafter, when the solder is solidified, the pressing pin 86 is raised. In this manner, the connection tabs 3 are soldered to the bus bar electrodes on the other surface (back surface) side following the bus bar electrodes 21 on the one surface (light receiving surface) side of the solar cell element 2. (Refer to the prior art in Patent Document 1)
The solar cell elements 2 connected in this way are further connected by a lateral wiring member to form an electrically connected solar cell element group 5.

In producing such a solar cell module, a sheet serving as the light receiving surface side filler 8 is placed on the translucent substrate 1, and the solar cell element 2 connected by the connection tab 3 or the like is further disposed thereon. . Furthermore, the sheet | seat used as the back surface side filler 9 is arrange | positioned on it, and the sheet | seat used as the back surface member 7 is laminated | stacked sequentially. 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. Thereafter, the module frame 4 is attached to the outer periphery of the integrated laminate (solar cell panel).
Japanese Patent Laid-Open No. 11-312820

  As described above, when the connection tab 3 is attached to the bus bar electrode 21 of the solar cell element 2 by soldering, the temperature becomes 200 ° C. or higher at the time of attachment, so the heat of the silicon substrate of the solar cell element 2 and the copper foil of the connection tab 3 When the temperature returns to room temperature due to the difference in expansion coefficient, the solar cell element 2 is warped.

  In particular, in recent solar cell modules, the use of solder that does not substantially contain lead is increasing due to environmental considerations. When using solder that does not substantially contain lead Then, since the soldering temperature is increased due to the physical properties of the solder, the degree of warping of the solar cell element may be further increased before and after soldering the connection tab as described above.

  Due to the warpage of the solar cell element 2, the bonding strength between the bus bar electrode 21 and the connection tab 3 of the solar cell element 2 decreases, and in some cases, the connection tab 3 is peeled off from the bus bar electrode 21, and the solar cell module manufacturing process In some cases, the yield of the solar cell module may be reduced, and the reliability of the solar cell module may be reduced.

  In particular, the connection tab 3 is made of a low resistance connection wiring material, such as a thin copper foil having a rectangular cross section and a width of several millimeters, with a solder coating on the entire surface of the connection tab 3 having a length of several hundred meters, This is wound on a reel or the like and cut into an appropriate length when used. For this reason, there is no solder coat at the cut end of the connection tab 3. Therefore, since this cut end is not soldered to the bus bar electrode 21 of the solar cell element 2, this cut end is a starting point from which the connection tab 3 is peeled off from the bus bar electrode 21 when stress is applied due to warping. There were many things.

  The present invention has been made in view of such problems, and its purpose is to strengthen the bonding strength between the electrode and the connection tab when the connection tab is soldered to the electrode on the solar cell element. Thus, it is to provide a solar cell module with a stable yield and a method for manufacturing the same.

The present invention has electrode portions on the light receiving surface side and the back surface side between the translucent light receiving surface side member and the back surface member, and is electrically connected to the electrode portions via a strip-shaped connection tab. In the solar cell module in which the plurality of solar cell elements are arranged, the connection tab has a bent portion that is bent toward the electrode portion side of the solar cell element at both ends in the longitudinal direction, and the bent portion and The space formed by the solar cell element is a solar cell module that is filled with solder .

  The connection tab and the electrode portion are soldered, and the angle of the bent portion of the connection tab before soldering is 110 ° to 160 °.

The present invention has electrode portions on the light-receiving surface side and the back surface side between the translucent light-receiving surface side member and the back surface member, and is electrically connected to the electrode portions via a strip-shaped connection tab. In the method for manufacturing a solar cell module in which a plurality of solar cell elements are arranged, when the both ends of the strip-shaped connection tab are brought into contact with the electrode portions of the solar cell element, the connection tab is separated from the electrode. It is pre-bent on the electrode part side of the solar cell element so that a space is formed, and a connection tab is arranged via solder on the electrode part of the solar cell element so that the space part is filled with solder, It is a method for manufacturing a solar cell module, wherein the connection tab is soldered to the electrode portion by blowing hot air to the overlapping portion of the electrode portion and the connection tab.

  Further, the bending angles of both end portions of the connection tab before soldering are 110 ° to 160 °, respectively.

  Further, a flux is applied to both ends of the connection tab.

  Furthermore, between the translucent light receiving surface side member and the back surface member, there are electrode portions on the light receiving surface side and the back surface side, respectively, and the electrode portions are electrically connected to each other via a strip-shaped connection tab. In the solar cell module in which a plurality of solar cell elements are arranged, the cross-sectional shape in the width direction of the connection tab is substantially straight on the surface side in contact with the electrode portion of the solar cell element, and the surface in contact with the electrode portion of the solar cell element The opposite side surface is convex.

  Moreover, it is desirable to provide a bent portion that is bent toward the electrode portion of the solar cell element at both ends in the longitudinal direction of the connection tab.

  Moreover, it is desirable that the connection tab and the electrode portion are soldered, and the angle of the bent portion of the connection tab before soldering is 110 ° to 160 °.

Between the translucent light receiving surface side member and the back surface member, there are a plurality of electrode portions on the light receiving surface side and the back surface side, respectively, and electrically connected to the electrode portions via a strip-shaped connection tab. In the solar cell module in which the solar cell elements are arranged,
The connection tab has bent portions that are bent toward the electrode portions of the solar cell element at both ends in the longitudinal direction, and the space formed by the bent portion and the solar cell element is filled with solder. It is . Thereby, when joining a connection tab to the electrode part (bus-bar electrode) of a solar cell element, the cut surface which is not solder-coated of the both ends of a connection tab faces the electrode side of a solar cell element. For this reason, the solder on the bus bar electrode of the solar cell element or the solder on the solder coated surface of the connection tab goes around this cut, and the cut is also joined to the electrode portion by the solder. Therefore, even when the connection tab has a stress due to the warp of the solar cell element as described above, the connection tab is not peeled off from the electrode. It can be produced.

  Further, in the above solar cell module, the bending angle of the bent portions at both ends of the connection tab before soldering to the solar cell element is set to 110 ° to 160 °, respectively. It is possible to ensure the effect of wrapping around the cut and joining the cut to the electrode portion by solder.

Between the translucent light receiving surface side member and the back surface member, a plurality of suns each having an electrode portion on the light receiving surface side and the back surface side and electrically connected to each other via a strip-shaped connection tab In the method for manufacturing a solar cell module in which a battery element is arranged, a space is formed between the connection tab and the electrode when contacting the electrode part of the solar cell element at both ends of the strip-shaped connection tab. As described above, it is bent in advance on the electrode part side of the solar cell element, and a connection tab is disposed on the electrode part of the solar cell element via solder so that the space part is filled with solder, and the electrode part and By soldering the connection tab to the electrode portion by blowing hot air on the overlapping portion of the connection tab, the solder-coated cut ends at both ends of the connection tab face the electrode side of the solar cell element. The bent portion is to be reliably heated with so made. As a result, the solder on the electrodes of the solar cell element or the solder on the solder coating surface of the connection tabs wrap around this cut, and the cut is also joined to the bus bar electrode by the solder. Therefore, even when stress is applied to the cut edge of the connection tab due to the warp generated in the solar cell element, the connection tab does not become a starting point from peeling off from the bus bar electrode, and the yield is stabilized in the solar cell module manufacturing method. It becomes possible.

  Furthermore, in the above solar cell module manufacturing method, the bending angle of both end portions of the connection tab before soldering is set to 110 ° to 160 °, respectively, so that the solder wraps around the cut of the connection tab, and the cut is also connected to the bus bar by the solder. The effect of being bonded to the electrode can be ensured.

  Further, in the above solar cell module manufacturing method, by applying a flux to the bent portions of both end portions of the connection tab before soldering, the cut end of the connection tab is securely joined to the electrode portion by soldering. As a result, the effect of improving the bonding strength can be ensured.

  Further, a plurality of electrodes having electrode portions on the light receiving surface side and the back surface side between the translucent light receiving surface side member and the back surface member and electrically connected to each other via a strip-shaped connection tab. In the solar cell module in which the solar cell elements are arranged, the cross-sectional shape in the width direction of the connection tab is substantially linear on the surface side in contact with the electrode portion of the solar cell element, and the surface in contact with the electrode portion of the solar cell element; By making the opposite surface have a convex shape, when this connection tab is soldered to the electrode part of the solar cell element, a solder fillet is formed at the lower part of the side surface of the connection tab, and the connection tab is joined to the electrode part. The strength can be increased.

  Further, by providing a bent portion that is bent toward the electrode portion side of the solar cell element at both ends in the longitudinal direction of the connection tab 100, when the connection tab is joined to the electrode portion of the solar cell element, the connection tab The cut ends of the both end portions that are not solder-coated face the electrode side of the solar cell element. For this reason, the solder on the bus bar electrode of the solar cell element or the solder on the solder coated surface of the connection tab goes around this cut, and the cut is also joined to the electrode portion by the solder. Therefore, even when the connection tab has a stress due to the warp of the solar cell element as described above, the connection tab is not peeled off from the electrode. It can be produced.

  In addition, the connection tab and the electrode portion are soldered, and the angle of the bent portion of the connection tab before soldering is 110 ° to 160, so that the solder wraps around the cut edge of the connection tab. Further, the effect of joining the cut bar to the bus bar electrode by the solder can be ensured.

  Hereinafter, the solar cell module of the present invention and the manufacturing method thereof will be described with reference to the accompanying drawings.

  FIG. 1 is a plan view of a light receiving surface side of a typical solar cell module, FIG. 2 is a partially exploded cross-sectional view of the module, and FIG. 3 is a plan view of a state where a connection tab is soldered to a solar cell element. FIG. 4 is a perspective view of a strip-shaped connection tab used in the solar cell module of the present invention, and FIG. 5 is a side view thereof.

  As the translucent substrate 1 that is the light receiving surface side member, 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 8 and the back surface side filler 9 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 or PVB may contain titanium oxide, pigment, or the like and be colored white, etc., but in the light-receiving surface side filler 8 in the method for manufacturing a solar cell module according to the present invention, the solar cell element 2 is colored. It is transparent because the amount of light incident on it decreases and power generation efficiency decreases.

  Moreover, EVA or PVB used for the back surface side filler 9 may be transparent, or may be colored white or the like by containing titanium oxide, pigment, or the like according to the surrounding installation environment where the solar cell module is installed.

  As the back surface sheet 7 as the back surface member, a weather-resistant fluorine-based resin sheet sandwiching aluminum foil so as not to transmit moisture, a polyethylene terephthalate (PET) sheet deposited with alumina or silica, or the like is used.

  The solar cell element 2 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 square. Inside the solar cell element 2 is formed a PN junction (not shown) 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 21 and the finger electrode 22 are formed by screen printing silver paste or the like. The surface of the bus bar electrode 21 is also a region where the protection and connection tabs 3 are soldered, and may be solder coated over almost the entire surface. The finger electrodes 22 have a width of about 0.1 to 0.2 mm and are formed in parallel with the sides of the solar cell element 2 to collect photogenerated carriers. In addition, the bus bar electrodes 21 are formed to collect the collected carriers and have a width of about 2 mm so as to attach the connection tabs, and about two bus bar electrodes 21 intersect the finger electrodes 22 perpendicularly. Such bus bar electrodes and finger electrodes are similarly formed on the back surface (non-light receiving surface) side of the solar cell element 2.

  The connection tab 3 is used to electrically connect the solar cell elements 2 to each other, and is used by applying a solder coat to the surface of a copper foil or the like and cutting it to an appropriate length. Then, one end side of the connection tab 3 is soldered to the bus bar electrode on the light receiving surface side of one adjacent solar cell element, and the other end side is soldered to the bus bar electrode on the back side of the other solar cell element. It was attached.

  And in producing such a solar cell module, the light receiving surface side filler 8 is placed on the translucent substrate 1, and the solar cell element 2 connected by the connection tab 3 or the like is further disposed thereon, Further, the back side filler 9 and the back sheet 7 are sequentially laminated thereon. In such a state, it is set in a laminator and heated at 100 to 200 ° C., for example, for 15 minutes to 1 hour while being pressurized under reduced pressure, thereby producing a solar cell panel in which these are integrated. Thereafter, the module frame 4 is attached to the outer peripheral portion of the panel.

  In this invention, as shown in FIG. 4, FIG. 5, the connection tab soldered to the bus-bar electrode 21 of the solar cell element 2 is shown. In the figure, 41 and 43 are linear portions, 42 is an inclined portion between solar cell elements, 40 and 44 are bent portions provided at both ends, and a1 and a2 are angles formed by the bent portions and the linear portions, respectively.

  The strip-like connection tab 3 according to the present invention is appropriately formed by soldering a low-resistance solar cell element connection wiring material such as copper foil on the entire surface thereof with a solder coating of about 20 to 70 μm on one side by plating or dipping. Cut to length and used. The width of the connection tab 3 is equal to or less than the width of the bus bar electrode 21 of the solar cell element 2 so that the connection tab 3 itself does not shade the light receiving surface of the solar cell element 2 when soldering. The length of the connection tab 3 overlaps almost all of the bus bar electrodes 21 of the solar cell elements 2, and further overlaps the bus bar electrodes on the non-light-receiving surface of the adjacent solar cell elements 2 with the interval between the predetermined solar cell elements 2. . When a general 150 mm square solar cell element 2 is used, the connection tab 3 has a width of about 1 to 3 mm and a length of about 200 to 300 mm. The reason why the connection tab 3 overlaps almost all the bus bar electrodes 21 of the solar cell element 2 is to reduce the resistance component of the solar cell element 21.

  Furthermore, one end of the connection tab 3 according to the present invention is bent toward the surface connected to the solar cell element 2 to form a bent portion 40, and between the solar cell elements that are the central portion of the connection tab 3. The located portion is bent in the same direction to the extent corresponding to the thickness of the solar cell element 2, and the inclined portion 42 is formed. Further, the other end portion 44 of the connection tab 3 is also bent toward the surface connected to the other solar cell element (that is, in a direction facing the bent portion 40), so that a bent portion 44 is formed. The width of the bent portions 40 and 44 at both ends is optimally about 2 to 7 mm.

  Further, at this time, the angle (inner angle on the joining surface side) a1 formed by the straight portion 41 and the bent portion 40 of the connection tab and the angle a2 formed by the straight portion 43 and the bent portion 44 are based on tests repeatedly performed by the inventor. And it is desirable that it is 110 degrees-160 degrees.

  Such a connection tab 3 is soldered to the solar cell element 2 through the attachment process shown in FIGS. FIG. 6 is a cross-sectional view showing a state in which the connection tab according to the present invention is arranged on the bus bar electrode of the solar cell element, and FIG. 7 is connected to the electrode of the solar cell element by soldering. It is sectional drawing which shows a mode.

  6 and 7, 69 is a pressing pin, 60 is a hot air blowing nozzle, 69a is an end pressing pin, 60a is an end hot air blowing nozzle, 61 is a hot air blowing direction from the end hot air blowing nozzle, 62 is The space part formed between solar cell elements by the bending part of a connection tab edge part is shown.

  In order to attach the connection tab 3 according to the present invention to the bus bar electrode 21 of the solar cell element 2 by soldering, the connection tab 3 is first arranged on the bus bar electrode 21 of the solar cell element 2. At this time, since the connection tab 3 is formed with the bent portion 40 as described above, it is separated from the end portion of the bus bar electrode 21 except for the end portion on the bent side as shown in FIG. The curved side is set to the bus bar electrode 21 side.

  In this state, the pressing pin 69 and the hot air blowing nozzle 60 are lowered to a position where the connection tab is fixed on the bus bar electrode 21 of the solar cell element 2 by the pressing pin 69. At this time, the position of the pressing pin 69a at the end is substantially the same as the length of the bent portion 40 of the connection tab 3 from the boundary between the bent portion 40 of the connection tab 3 and the straight portion 41 on the straight portion 41 of the connection tab 3. Try to be as far away.

  By pressing the connection tab 3 onto the bus bar electrode 21 of the solar cell element 2 with the pressing pins 69 and 69a in this way, as shown in FIG. 7, the connection tab 3 and the bus bar are located closer to the center than the position of the pressing pin 69a. The electrode 21 is in contact. Further, on the end side from the position of the end pressing pin 69 a, the position of the end pressing pin 69 a is set to the length of the bent portion 40 of the connection tab 3 from the boundary line between the bent portion 40 and the straight portion 41 of the connection tab 3. Since the boundary between the bent portion 40 and the straight portion 41 of the connection tab 3 is a vertex, an isosceles triangle is drawn, and the cut end at the end of the connection tab 3 is a bus bar. It will face the electrode 21 side.

  In such a state, hot air of about 400 to 500 ° C. is blown from the hot air blowing nozzle 60 onto the connection tab 3 for about 1 to 3 seconds.

  At this time, in the connection tab mounting method according to the present invention, the hot air is blown from an oblique direction so that the hot air blowing direction 61 from the hot air blowing nozzle 60a at the end is substantially perpendicular to the bent portion 60 of the connecting tab. Like that.

  By doing so, the cut at the end of the connection tab 3 faces the bus bar electrode 21 side, and hot air efficiently hits the bent portion 40 of the connection tab 3, so that the cut at the end of the connection tab 3 is soldered. And is joined to the bus bar electrode 21 by soldering.

  Further, the bent portion 40 at the end of the connection tab 3 also melts the solder inside the space 62 (inside the isosceles triangle) formed between the solar cell element 2 and this portion is almost filled with solder. Thus, a solder fillet is formed, and the bonding strength with the bus bar electrode 21 becomes strong at the end of the connection tab 3.

  Therefore, even when stress is applied to the solar cell element 2 due to warping, the connection tab 3 is not peeled off from the bus bar electrode 21 from the cut end or the end of the connection tab 3, and the yield in the solar cell module manufacturing method is as follows. Is stable.

  Furthermore, in the method for attaching the connection tab 3 according to the present invention, it is desirable to apply a flux in advance to the bent portion 40 (particularly, the cut end portion) of the connection tab 3. The application method can be performed by dipping the bent portion 40 in a flux tank and drying it. The flux to be applied is preferably an RMA type so that cleaning after soldering is unnecessary.

  By previously applying flux to the bent portion 40 of the connection tab 3 in this way, the solderability of this portion is improved, and the cut end of the connection tab 3 is covered with solder, and the bus bar electrode 21 is covered. The effect of joining by solder and the inside of the space 62 are almost filled with solder, and the effect of strengthening the joining strength with the electrode at the end of the connection tab can be ensured.

  In the above description, the case where the connection tab 3 is joined to the bus bar electrode 21 formed on one main surface of the solar cell element 2, for example, the light receiving surface, is described. The bent portion 44 is soldered to the bus bar electrode on the back side of the other solar cell element to be connected by the same attachment method.

  In FIG. 5, it is desirable that the angles a1 and a2 of the bent portions 40 and 44 be 110 ° to 160 °. If the angle is less than 110 °, the angle becomes steep. Therefore, when the connection tab 3 is attached to the bus bar electrode 21 of the solar cell element 2, a portion that is not soldered to the bus bar electrode 21 may occur. The resistance component of the battery module may increase and the electrical output may decrease. If the angle exceeds 160 °, the solder on the bus bar electrode 21 of the solar cell element 2 or the solder on the solder tab surface of the connection tab 3 does not sufficiently wrap around the cut edge of the connection tab 3. The electrode 21 may not be joined. For this reason, the non-soldered cut ends at both ends of the connection tab 3 are surely directed to the bus bar electrode side of the solar cell element 2, and solder on the bus bar electrode 21 of the solar cell element 2 or solder on the solder coated surface of the connection tab 3 is The angles a1 and a2 are preferably 160 ° or less in order to melt and wrap around the cut, and the cut is also stably joined to the bus bar electrode by solder.

  FIG. 9 is a perspective view showing another embodiment of the connection tab according to the present invention. In FIG. 9, 100 is a connection tab, 101 is a surface of the connection tab in contact with the electrode portion of the solar cell element, 102 is a surface of the connection tab opposite to the surface of the electrode portion of the solar cell element, and 103 is a width direction of the connection tab. The cross section of is shown.

  In the connection tab 100, the shape of the cross-section 103 in the width direction is such that there are fine irregularities such as a solder coat surface on the surface 101 side of the connection tab in contact with the electrode part of the solar cell element, but a substantially flat substantially straight line On the surface 102 side of the connection tab opposite to the surface in contact with the electrode portion of the solar cell element, the thickness of the central portion in the width direction is a convex shape that is thicker than both ends.

  For example, in the connection tab 100, the width of the copper foil used for this is 1.5 mm, the thickest part is 0.2 mm, the cross-sectional shape is a circle with a diameter of 3 mm, and the chord length is 1.5 mm. By the way, it is a convex shape cut out.

  A copper foil having such a cross-sectional shape can be freely produced by making the shape of the extrusion port when the copper material is extruded into a strip shape into a desired shape. Further, the surface of the strip-shaped copper foil, which is about 20 to 70 μm on one side and is solder-coated (not shown) as uniformly as possible by plating or dipping, is cut into an appropriate length and used as a connection tab.

  FIG. 10 is a cross-sectional view showing a state in which the connection tab 100 is connected to the bus bar electrode 21 of the solar cell element 2 by soldering. In FIG. 10, reference numeral 104 denotes a solder fillet, and 105 denotes a solder layer.

  As described above, when the connection tab 100 is soldered onto the bus bar electrode 21 of the solar cell element 2 by hot air or the like, the solder layer 105 is formed between the bus bar electrode 21 and the connection tab 100, and the sun of the connection tab 100 is also formed. The solder that coats the surface 102 opposite to the surface in contact with the electrode portion of the battery element also melts and flows down by its own weight. For this reason, solder accumulates in the lower part of the side surface of the connection tab in contact with the connection tab 100 and the bus bar electrode 21, and a solder fillet is formed so as to connect both the connection tab 100 and the bus bar electrode 21. By forming this fillet, the bonding strength between the connection tab and the electrode portion can be strengthened.

  Further, when the solar cell elements connected by the connection tabs are sealed with the light receiving surface side filler 8 and the back surface side filler 9 as described above to produce a solar cell module and install it outdoors, the temperature change of the solar cell module In addition, since there is a difference in thermal expansion coefficient between the light receiving surface side filler 8 and the back surface side filler 9 such as EVA and the solar cell element, when the cross-sectional shape of the connection tab is rectangular, the light receiving surface side filler 8 and Although the force (deformation) due to thermal expansion and contraction of the back surface side filler 9 is received by the side surface of the connection tab, the bonding strength between the connection tab and the electrode portion may be reduced. 100, the force due to thermal expansion and contraction of the back surface side filler 9 can be escaped by the convex shape on the surface 102 side opposite to the surface in contact with the electrode portion of the solar cell element as described above. Bond strength between the electrode and electrode Do not be.

  Furthermore, one end of the connection tab 100 according to the present invention is bent toward the surface connected to the solar cell element 20 as described above to form a bent portion, and further, the solar cell that is the central portion of the connection tab 100 The portions located between the elements are bent in the same direction to the extent corresponding to the thickness of the solar cell element 20 to form an inclined portion. Moreover, the other end part of the connection tab 100 is also bend | folded to the surface side connected to another solar cell element, and a bending part is formed. The width of the bent portions at both ends is optimally about 2 to 7 mm.

  Further, as described above, the angle formed by the straight portion and the bent portion of the connection tab (inner angle on the surface to be joined) and the angle formed by the straight portion and the bent portion are based on the results of experiments conducted repeatedly by the present inventors. And it is desirable that it is 110 degrees-160 degrees.

  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 be applied to a thin film solar cell.

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

It is a top view of a typical solar cell module. It is an exploded sectional view of the portion of a solar module. It is a top view of the state which connected the connection tab to the solar cell element. The perspective view of the connection tab which concerns on this invention is shown. 1 shows a cross-sectional view of a connection tab according to the present invention. It is sectional drawing which shows the state which has arrange | positioned the connection tab which concerns on this invention on the bus-bar electrode of a solar cell element. It is sectional drawing which shows a mode that the connection tab which concerns on this invention is connected on the bus-bar electrode of a solar cell element by soldering. 1 shows a conventional device for connecting a connection tab to a solar cell element. It is a perspective view which shows another Example of the connection tab which concerns on this invention. It is sectional drawing of the state which connected the connection tab which concerns on this invention to the bus-bar electrode of a solar cell element by soldering.

Explanation of symbols

2: solar cell element 3, 100: connection tab 21: bus bar electrode 22: finger electrode 6, 60a, 85: hot air blowing nozzle 69, 69a, 86: pressing pin 40, 44: bent part a1, a2: bent part Angle 102; surface 102 of the connection tab that contacts the electrode portion of the solar cell element; surface 103 of the connection tab opposite to the surface of the electrode portion of the solar cell element; cross section 104 of the connection tab in the width direction; solder fillet 105; Solder layer

Claims (5)

Between the translucent light receiving surface side member and the back surface member, there are a plurality of electrode portions on the light receiving surface side and the back surface side, respectively, and electrically connected to the electrode portions via a strip-shaped connection tab. In the solar cell module in which the solar cell elements are arranged,
The connection tab has bent portions that are bent toward the electrode portions of the solar cell element at both ends in the longitudinal direction, and the space formed by the bent portion and the solar cell element is filled with solder. and a solar cell module, characterized by that. 2. The solar cell module according to claim 1, wherein the connection tab and the electrode portion are soldered, and the angle of the bent portion of the connection tab before soldering is 110 ° to 160. Between the translucent light receiving surface side member and the back surface member, a plurality of suns each having an electrode portion on the light receiving surface side and the back surface side and electrically connected to each other via a strip-shaped connection tab In the method for manufacturing a solar cell module in which a battery element is arranged, a space is formed between the connection tab and the electrode when contacting the electrode part of the solar cell element at both ends of the strip-shaped connection tab. As described above, it is bent in advance on the electrode part side of the solar cell element, and a connection tab is disposed on the electrode part of the solar cell element via solder so that the space part is filled with solder, and the electrode part and A method for manufacturing a solar cell module, wherein the connection tab is soldered to the electrode portion by blowing hot air over the overlapping portion of the connection tab. The solar cell module manufacturing method according to claim 3, wherein bending angles of both end portions of the connection tab before soldering are 110 ° to 160 °, respectively. 4. The method for manufacturing a solar cell module according to claim 3, wherein a flux is applied to both ends of the connection tab.

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