JP2016167641A - Solar battery module and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery module having a tab line that can maintain an excellent shape condition and secure sufficient connection reliability, and a manufacturing method for the same.SOLUTION: On front and back surfaces of a tab line 3 are formed uneven portions 21 including a plurality of convex portions and concave portions which are alternately provided in the width direction thereof and continuous over the longitudinal direction thereof. One end of the uneven portion 21 is connected to a bus bar electrode 11 through an adhesive resin material, and the other end of the uneven portion 21 is connected to a back surface electrode 13 through an adhesive resin material. In the tab line 3, an uneven angle at which a line segment formed by connecting the apex of a convex portion and the apex of a concave portion adjacent to the convex portion intersects to a line segment formed by connecting the apexes of concave portions at both the sides of the convex portion ranges from not less than 10° to not more than 50°.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a solar cell module in which connection electrodes of a plurality of solar cells are electrically connected to each other by tab wires, and a method for manufacturing the solar cell module.

  Generally, a solar cell is used as a solar cell module that realizes an output of 100 W or more by connecting a plurality of solar cells in series.

  In the crystalline silicon solar cell module, a plurality of adjacent solar cells are connected by tab wires made of a conductive material such as a ribbon-like copper foil solder-coated as an interconnector. One end of the tab wire is connected to the surface electrode of one solar cell, and the other end is connected to the back electrode of the adjacent solar cell, thereby connecting the solar cells in series.

  In recent years, as a tab line, one having an uneven portion formed on one surface has been proposed. For example, as shown in FIG. 11, the tab line 100 is formed in a long shape, and the uneven portion 102 is formed on the light receiving side surface 101a. As shown in FIG. 12, the concavo-convex portion 102 is formed by alternately providing a plurality of convex portions 102 a and concave portions 102 b extending in the longitudinal direction of the tab wire 100 in the width direction.

  The tab wire 100 is connected to the front surface electrode 103 a of the solar battery cell 103 through the conductive adhesive film 104 on the back surface 101 b. Thereby, since the uneven | corrugated | grooved part 102 is orient | assigned to the light-receiving surface side, the incident light is scattered by the uneven | corrugated | grooved part 102. The scattered light is reflected by the protective glass surface and reenters the light receiving surface. Thereby, the solar cell module provided with the tab wire 100 exhibits a light containment effect and improves the power generation efficiency, and as a result, the power generation efficiency can be improved.

  Patent Document 1 describes a configuration of a solar cell module including strings in which a plurality of solar cells are arranged in series by tab wires having uneven portions formed on the surface on the light receiving side. .

  On the other hand, Patent Document 2 describes a solar cell module including a tab wire having a concavo-convex portion formed on the surface facing the connection electrode. The convex portion of the tab wire described in Patent Document 2 is in contact with the connection electrode, and a conductive resin material is filled between the tab wire and the connection electrode. And the connection reliability (adhesion strength) of a tab wire can be improved by making the height of an uneven | corrugated | grooved part high.

JP 2010-16300 A JP 2008-147567 A

  As described above, the solar cell including the tab line having the uneven portion formed on one surface and the surface opposite to the surface on the surface electrode on the front electrode and the back electrode is not attached to the surface when the tab wire is bonded. There will be a difference in pressure applied to the back surface. For this reason, in the solar battery cell, stress strain occurs on the surface electrode side and the back electrode side. A solar battery cell may be cracked or warped when stress strain occurs.

  Here, in crystalline silicon solar cells, it has become a problem to procure a large amount of silicon as a raw material at a low cost. In recent years, a silicon wafer is made extremely thin (for example, 200 μm to 150 μm) using a polycrystalline silicon ingot. It has begun to be used for cutting and mass production. In such a thin solar cell, cracks and warpage due to stress strain are more likely to occur.

  Moreover, there is a possibility that the flat surfaces facing the front electrode and the back electrode cannot be connected to the front electrode and the back electrode with sufficient adhesive strength.

  The present invention has been proposed in view of such a conventional situation, and can maintain a good shape state of the solar battery cell and obtain sufficient connection reliability with the tab wire. It is an object of the present invention to provide a solar cell module capable of achieving the above and a method for manufacturing such a solar cell module.

  In order to solve the above-described problem, a solar battery module according to the present invention includes, among a plurality of solar battery cells, another solar battery cell adjacent to one of the surface electrode of the predetermined solar battery cell and the predetermined solar battery cell. In the solar cell module in which the back electrode is connected by a tab line, the tab line is an unevenness in which a plurality of convex portions and concave portions that are continuous in the longitudinal direction are alternately provided in the width direction on both the front and back surfaces. Part is formed, one end is connected to the surface electrode and the other end is connected to the back electrode via the adhesive resin material, respectively, connecting the apex of the convex part and the apex of the concave part adjacent to the convex part The concavo-convex angle formed by the line segment and the line segment connecting the apexes of the concave portions adjacent to both sides of the convex portion is 10 ° or more and 50 ° or less.

  Moreover, in order to solve the subject mentioned above, the manufacturing method of the solar cell module which concerns on this invention is adjacent to one of the surface electrode of a predetermined solar cell, and one of a predetermined solar cell among several solar cells. In the method for manufacturing a solar battery module in which the back electrode of another solar battery cell is connected by a tab wire, a crimping process for crimping the tab wire to each of the front electrode and the back electrode of the solar battery cell via an adhesive resin material The tab line is formed on each of the front and back surfaces with a plurality of protrusions and recesses that are alternately provided in the width direction on the front and back surfaces. The concavo-convex angle formed by the line segment connecting the apexes of the adjacent recesses and the line segment connecting the apexes of the recesses adjacent to both sides of the convex part is 10 ° or more and 50 ° or less. One end of the tab wire The electrode and the other end of the tab wire are connected to the back electrode via an adhesive resin material.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to prevent a distortion of a photovoltaic cell and maintaining a favorable shape state, it becomes possible to obtain sufficient connection reliability between tab wires.

It is a disassembled perspective view which shows the structure of a solar cell module. It is longitudinal direction sectional drawing of the string of a photovoltaic cell. It is a perspective view which shows the photovoltaic cell connected by the tab wire. It is sectional drawing of a photovoltaic cell. It is width direction sectional drawing of a tab line. It is width direction sectional drawing of an electroconductive adhesive film. It is a schematic diagram which shows an example of the form of a conductive adhesive film. It is a schematic diagram for demonstrating the temporary crimping | compression-bonding process of a tab wire. It is a schematic diagram for demonstrating the main crimping | compression-bonding process of a tab wire. It is sectional drawing of a photovoltaic cell. It is a perspective view which shows the solar cell connected by the conventional tab wire. It is sectional drawing of the width direction of the conventional tab wire.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings.

[Solar cell module]
FIG. 1 is an exploded perspective view showing a configuration of a solar cell module 1 having a tab wire to which the present invention is applied. The solar cell module 1 includes strings 4 in which a plurality of solar cells 2 are connected in series by tab wires 3 serving as interconnectors, and includes a matrix 5 in which a plurality of strings 4 are arranged.

  In the solar cell module 1, a matrix 5 is sandwiched between sheets 6 of a sealing adhesive, laminated together with a front cover 7 provided on the light receiving surface side and a back sheet 8 provided on the back surface side, and is surrounded by aluminum. It is formed by attaching a metal frame 9 such as.

  As the sealing adhesive for the sheet 6, for example, a translucent sealing material such as ethylene vinyl acetate resin (EVA) is used. Moreover, as the surface cover 7, for example, a light-transmitting material such as glass or light-transmitting plastic is used. Further, as the back sheet 8, a laminated body in which glass or aluminum foil is sandwiched between resin films is used.

  FIG. 2 is a longitudinal sectional view of the strings 4 formed by connecting the solar cells 2 in series. Each solar battery cell 2 includes a photoelectric conversion element 10. The photoelectric conversion element 10 is formed by stacking a crystalline silicon solar cell module using a single crystal silicon photoelectric conversion element, a polycrystalline photoelectric conversion element or the like, a cell made of amorphous silicon, and a cell made of microcrystalline silicon or amorphous silicon germanium. Various photoelectric conversion elements 10 such as a thin-film silicon solar cell using the photoelectric conversion element that has been made can be used.

  Further, the light receiving surface of the photoelectric conversion element 10 is provided with a bus bar electrode 11 and finger electrodes 12 that are collector electrodes formed in a direction substantially orthogonal to the bus bar electrode 11 as surface electrodes. A back electrode 13 made of aluminum, silver, or the like is provided on the surface of the photoelectric conversion element 10 opposite to the light receiving surface.

  Each solar battery cell 2 forms a string 4 by electrically connecting a bus bar electrode 11 of a predetermined solar battery cell 2 and a back electrode 13 of an adjacent solar battery cell 2 by a tab wire 3. To do.

  Specifically, at one end 3a of the tab wire 3, one surface 30b of the tab wire 3 is connected to the bus bar electrode 11 of the solar battery cell 2 via the conductive adhesive film 15a. Further, the other surface 30a of the tab wire 3 at the other end 3b of the tab wire 3 is connected to the back surface electrode 13 of the solar battery cell 2 adjacent to the other via the conductive adhesive film 15b.

  The finger electrode 12 is formed by applying Ag paste and heating. The finger electrode 12 is formed over substantially the entire light receiving surface of the solar battery cell 2. The finger electrodes 12 are formed with lines having a width of about 100 μm, for example, at a predetermined interval, for example, every 2 mm.

  The bus bar electrode 11 is formed by the same method as the finger electrode 12. The bus bar electrode 11 intersects with the bus bar electrode 11 in the form of a line, for example, 1 mm wide on the surface of the photoelectric conversion element 10 serving as the light receiving surface of the solar battery cell 2 in order to reduce the area that blocks incident light and suppress shadow loss. It is formed to do.

  The number of bus bar electrodes 11 is appropriately set in consideration of the size and resistance of the solar battery cell 2. A conductive adhesive film 15 a is provided on the bus bar electrode 11, and an end portion 3 a of the tab wire 3 is provided thereon. Thereby, the bus-bar electrode 11 is connected with the surface 30b of the edge part 3a of the tab wire 3 via the electroconductive adhesive film 15a.

  The back electrode 13 is formed of an electrode made of aluminum, silver, or the like on the back surface of the photoelectric conversion element 10 by, for example, screen printing or sputtering. The back electrode 13 is connected to the surface 30a of the end 3b of the tab wire 3 through the conductive adhesive film 15b.

  In this way, the solar battery cell 2 included in the solar battery module 1 is mechanically connected to the tab wire 3 on both the front and back surfaces and electrically connected to the adjacent solar battery cell 2 via the tab wire 3. .

[Tab line]
As shown in FIG. 3, the tab wire 3 is formed in a long shape using, for example, a ribbon-like copper foil having a thickness of 50 to 300 μm, and gold plating, silver plating, tin plating, solder plating, etc. as necessary. Is given. As for the tab wire 3, the uneven | corrugated | grooved part 21 is formed in the longitudinal direction in each of one surface 30a and the other surface 30b. The tab wire 3 has one end 3a fixed and connected to the bus bar electrode 11 of the solar cell 2, and the other end 3b fixed and connected to the back surface electrode 13 of the adjacent solar cell. Is done.

  Specifically, as shown in FIG. 4, the tab line 3 has a plurality of convex portions 31 and concave portions 32 that are continuous in the longitudinal direction of the tab line 3 on both the front and back surfaces, that is, both surfaces 30a and 30b. The concavo-convex portion 21 is formed by being provided on the surface. The concavo-convex portion 21 is formed by press-molding a plated ribbon-like copper foil or the like.

  Further, the uneven portion may be subjected to a surface treatment by a known method. The convex portions are not limited to those having an acute angle, and may be slightly rounded within a range in which the concave / convex angle α can be measured.

  The tab line 3 has a front and back symmetrical shape with the center line m1 as a boundary in the cross section in the width direction. Thereby, the photovoltaic cell 2 in which the front and back symmetrical tab wires 3 are connected to the bus bar electrode 11 and the back surface electrode 13 can prevent the warpage caused by the stress strain generated when the tab wires 3 are connected.

  That is, the tab wire 3 has a symmetrical shape on the front and back sides, so that when the tab wire 3 is connected to each of the bus bar electrode 11 and the back surface electrode 13 by heating and pressing described later, stress is applied evenly on the front side and the back side of the solar cell 2. . For this reason, the photovoltaic cell 2 can minimize the stress difference applied to the front surface and the back surface on the light receiving surface side. Thereby, since the photovoltaic cell 2 can suppress the stress distortion resulting from the shape of the tab wire 3 in front and back both surfaces to the minimum, it becomes possible to prevent generation | occurrence | production of a crack and curvature.

  As shown in FIG. 5, the uneven portion 21 on the surface 30b of the end 3a of the tab wire 3 is connected to the bus bar electrode 11 of the solar cell 2 through the conductive adhesive film 15a. The As will be described later, the conductive adhesive film 15a enters the concave portion 32 of the concave-convex portion 21 when the binder resin flows by heating. Thereby, as will be described later, the tab wire 3 having a predetermined unevenness angle can increase the connection strength between the bus bar electrode 11 and the back electrode 13 of the solar battery cell 2.

  Further, in the predetermined solar cell 2, incident light incident on the uneven portion 21 on the surface 30a of the end portion 3a of the tab wire 3 is scattered by the uneven portion 21 on the light receiving surface side, and the scattered light is glass. The light is reflected by the front cover 7 and enters the light receiving surface. Thereby, the photovoltaic cell 2 can improve high power generation efficiency.

  Further, the uneven portion 21 on the surface 30a of the end portion 3b of the tab wire 3 is connected to the back surface electrode 13 of the solar battery cell 2 adjacent to the predetermined solar battery cell 2 through the conductive adhesive film 15b. Also in this connection, the conductive adhesive film 15b enters the concave portion 32 of the concave and convex portion 21 by the flow of the binder resin by heating, so that the connection reliability (adhesion strength) with the back electrode 13 can be increased.

  Thus, as for the tab wire 3 with which the solar cell module 1 is provided, the uneven | corrugated | grooved part 21 which has a predetermined | prescribed uneven | corrugated angle is formed in front and back both surfaces 30a and 30b. Thereby, in the solar cell module 1, in the predetermined solar cell 2, the tab wire 3 and the bus bar electrode 11, the tab wire 3 and the back electrode 13 are mechanically connected with high adhesive strength, respectively, and the predetermined solar cell The bus bar electrode 11 of the battery cell 2 and the back electrode 13 of the solar battery cell 2 adjacent to the predetermined solar battery cell 2 are electrically connected with high connection reliability.

  Next, the unevenness angle of the uneven portion 21 will be described. As shown in FIG. 4 above, in the cross section in the width direction of the tab line 3, a line segment a1b1 connecting the vertex b1 of the convex portion 31 and the vertex (lowest point) a1 of the concave portion 32 adjacent to both sides of the convex portion 31. And the angle formed by the line segment a1a1 connecting the vertices a1 of the concave portions 32 adjacent to the convex portion 31 is defined as the concave / convex angle α of the tab line 3. The cross section of the tab line 3 has a symmetrical shape with the center line m1 as a boundary. For this reason, also on the other surface 30b, the same uneven | corrugated angle (alpha) can be obtained from the convex part 31 and the recessed part 32. FIG.

  The unevenness angle α is preferably 10 ° or more and 50 ° or less, and particularly preferably 20 ° or more and 40 ° or less. By setting the concavo-convex angle α to be 10 ° or more and 50 ° or less, incident light can be scattered and reflected by the surface cover 7, and a light containment effect can be exhibited in the solar cell module 1 to increase power generation efficiency. it can.

  Further, by setting the unevenness angle α to 10 ° or more, a sufficient amount of the conductive adhesive film 15 (conductive adhesive films 15a and 15b) enters the concave portion 32 of the concave and convex portion 21 due to the flow caused by heating. 3 and the bus bar electrode 11, and the connection reliability in the tab wire 3 and the back electrode 13 can be enhanced.

Then, as shown in FIG. 5, the tab wire 3 is connected to the bus bar electrode 11 of the solar battery cell 2 with the uneven portion 21 of the surface 30 b bonded to the conductive adhesive film 15 a with high adhesive strength. When incident light is incident on the uneven portion 21 of the surface 30 a, the incident light is scattered by the uneven portion 21.
Then, the scattered light is reflected by the surface cover 7, which is a protective glass surface, and reenters the photoelectric conversion element 10.

  In this way, the solar cell module 1 can exhibit the light containment effect and improve the power generation efficiency. As a result, the solar cell module 1 can improve the power generation efficiency, and a sufficient amount of conductive adhesion to the concave portion 32 of the concavo-convex portion 21. When the film 15a enters, the connection reliability between the tab wire 3 and the bus bar electrode 11 can be improved.

[Conductive adhesive film]
For example, as shown in FIG. 6, the conductive adhesive film 15 includes a thermosetting binder resin layer 23 containing conductive particles 24 at a high density. The conductive adhesive film 15 preferably has a minimum melt viscosity of 100 to 100,000 Pa · s from the viewpoint of indentability.

  If the minimum melt viscosity of the conductive adhesive film 15 is too low, the resin will flow in the process of low pressure bonding to main curing, and connection failure and protrusion to the cell light-receiving surface are likely to occur, causing a reduction in light receiving rate. Moreover, even if the minimum melt viscosity is too high, defects are likely to occur when the film is adhered, and the connection reliability may be adversely affected. The minimum melt viscosity can be measured while a sample is loaded in a predetermined amount of rotational viscometer and raised at a predetermined temperature increase rate.

  The conductive particles 24 used for the conductive adhesive film 15 are not particularly limited, and examples thereof include metal particles such as nickel, gold, and copper, resin particles that are gold-plated, and resin particles that are gold-plated. The outermost layer of the particles may be an insulating coating. In addition, by containing flat flaky metal particles as the conductive particles 24, the number of the conductive particles 24 that overlap each other can be increased, and good conduction reliability can be ensured.

  Moreover, it is preferable that the electroconductive adhesive film 15 is 10-10000 kPa * s at the normal temperature vicinity, More preferably, it is 10-5000 kPa * s. When the viscosity of the conductive adhesive film 15 is in the range of 10 to 10,000 kPa · s, when the conductive adhesive film 15 is, for example, a tape-shaped reel body described later, so-called protrusion can be prevented, A predetermined tack force can be maintained.

  The composition of the binder resin layer of the conductive adhesive film 15 is not particularly limited as long as it does not impair the above-described characteristics, but more preferably a film-forming resin, a liquid epoxy resin, a latent curing agent, a silane cup Contains a ring agent.

  The film-forming resin corresponds to a high molecular weight resin having an average molecular weight of 10,000 or more, and preferably has an average molecular weight of about 10,000 to 80,000 from the viewpoint of film formation. As the film-forming resin, various resins such as an epoxy resin, a modified epoxy resin, a urethane resin, and a phenoxy resin can be used. Among them, a phenoxy resin is preferably used from the viewpoint of the film formation state, connection reliability, and the like. .

  The liquid epoxy resin is not particularly limited as long as it has fluidity at room temperature, and all commercially available epoxy resins can be used. Specific examples of such epoxy resins include naphthalene type epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, bisphenol type epoxy resins, stilbene type epoxy resins, triphenolmethane type epoxy resins, phenol aralkyl type epoxy resins. Resins, naphthol type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, and the like can be used. These may be used alone or in combination of two or more. Moreover, you may use it combining suitably with other organic resins, such as an acrylic resin.

  As the latent curing agent, various curing agents such as a heat curing type and a UV curing type can be used. The latent curing agent does not normally react but is activated by some trigger and starts the reaction. The trigger includes heat, light, pressurization, etc., and can be selected and used depending on the application. When a liquid epoxy resin is used, a latent curing agent made of imidazoles, amines, sulfonium salts, onium salts, or the like can be used.

  As the silane coupling agent, epoxy, amino, mercapto sulfide, ureido, and the like can be used. Among these, in this Embodiment, an epoxy-type silane coupling agent is used preferably. Thereby, the adhesiveness in the interface of an organic material and an inorganic material can be improved.

  Moreover, it is preferable to contain an inorganic filler as another additive composition. By containing an inorganic filler, the fluidity of the resin layer during pressure bonding can be adjusted, and the particle capture rate can be improved. As the inorganic filler, silica, talc, titanium oxide, calcium carbonate, magnesium oxide and the like can be used, and the kind of the inorganic filler is not particularly limited.

  FIG. 7 is a schematic diagram showing an example of the form of the conductive adhesive film 15. The conductive adhesive film 15 is provided with a release substrate 25 on one surface thereof to form a film laminate, and is formed into a tape shape. The tape-like conductive adhesive film 15 is wound and laminated on the reel 26 so that the peeling base material 25 is on the outer peripheral side, thereby forming a reel body 27.

  There is no restriction | limiting in particular as the peeling base material 25, PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), PTFE (Polytetrafluoroethylene) etc. can be used. In addition, the conductive adhesive film 15 may have a structure having a transparent cover film on the surface opposite to the surface on which the release substrate 25 is provided.

  At this time, you may use the tab wire 3 as a cover film affixed on a binder resin layer. By previously laminating and integrating the tab wire 3 and the conductive adhesive film 15, the peeling base material 25 is peeled off in actual use, and the conductive adhesive film 15 is placed on the bus bar electrode 11 or the back electrode 13. By bonding, the tab wire 3 can be connected to the bus bar electrode 11 and the back electrode 13. The conductive adhesive film 15 is not limited to a reel body shape, and may be, for example, a strip shape.

  When the conductive adhesive film 15 is provided as the reel body 27, by setting the viscosity of the conductive adhesive film 15 in the range of 10 to 10000 kPa · s, deformation of the conductive adhesive film 15 is prevented, and a predetermined dimension is set. Can be maintained. Similarly, when two or more conductive adhesive films 15 are stacked in a strip shape, deformation can be prevented and a predetermined dimension can be maintained.

  The conductive adhesive film 15 can be manufactured, for example, by the following method. First, the conductive particles 24, the film-forming resin, the liquid epoxy resin, the latent curing agent, and the silane coupling agent are dissolved in a solvent. As the solvent, toluene, ethyl acetate or the like, or a mixed solvent thereof can be used. And the solution for resin production obtained by making it melt | dissolve is apply | coated on a peeling sheet, and a solvent is volatilized. Thereby, the conductive adhesive film 15 is obtained.

[Manufacturing process]
Next, the manufacturing process of the solar cell module 1 will be described. In the solar cell module 1, the temporary bonding step of temporarily bonding the conductive adhesive film 15 to the bus bar electrode 11 and the back electrode 13, the arranging step of arranging the solar cells 2, and the tab wire 3 on the conductive adhesive film 15. Temporary press-bonding step that is arranged on the bus bar electrode 11 and the back electrode 13 by hot pressing at low temperature and low pressure, and the conductive adhesive film 15 is thermally cured by hot pressing from the tab wire 3, and the tab wire 3 and the bus bar. A main pressure bonding step of connecting the electrode 11 and the back electrode 13.

  First, the uncured conductive adhesive film 15 is temporarily pasted on the bus bar electrode 11 and the back electrode 13 of each solar battery cell 2 (temporary pasting step). In the temporary attachment step of the conductive adhesive film 15, for example, the conductive adhesive film 15 wound around the reel body 27 is transported to a predetermined position on the front and back sides of the solar battery cell 2 and pressed by the temporary attachment head. Then, the conductive adhesive film 15 is temporarily attached.

  By heating the conductive adhesive film 15 with a temporary sticking head (not shown) at a temperature (for example, 40 to 60 ° C.) that does not cause the main curing to occur for a predetermined time (for example, 1 to 5 seconds). The conductive adhesive film 15 is temporarily attached to the solar battery cell 2. The solar cells 2 to which the conductive adhesive film 15 is temporarily attached are arranged in the order in which they are connected in series.

  Next, the tab wire 3 is temporarily pressure-bonded onto the conductive adhesive film 15 with respect to each solar battery cell 2 arranged at a predetermined position facing the pair of upper and lower temporary pressure-bonding heads 26 (temporary pressure-bonding step). At this time, as shown in FIGS. 2 and 8, one of the tab wires 3 is formed on the bus bar electrode 11 formed on the surface of the preceding one solar battery cell 2 through the uncured conductive adhesive film 15 a. The end 3a is temporarily crimped. And the other end part 3b of the tab wire 3 is temporarily crimped | bonded to the back surface electrode 13 of the other subsequent photovoltaic cell 2 via the uncured conductive adhesive film 15b.

  Similarly, a tab is formed on the bus bar electrode 11 formed on the surface of the solar battery cell 2 and on the back electrode 13 of the solar battery cell 2 subsequent to the solar battery cell 2 through an uncured conductive adhesive film 15. One end 3a and the other end 3b of the wire 3 are temporarily crimped. In this way, adjacent solar cells 2 are connected in series with the tab wire 3.

  As described above, in the tab wire 3, the surface 30b on which the concave and convex portion 21 is formed is temporarily crimped onto the bus bar electrode 11 at one end 3a, and the concave and convex portion 21 is formed on the other end 3b. The front surface 20 a is temporarily pressure-bonded to the back electrode 13.

  In the temporary crimping step, the temporary crimping of the tab wire 3 is performed by the temporary crimping head 26. The temporary press-bonding head 26 is heated to a temperature (for example, about 70 to 100 ° C.) at which the curing reaction of the conductive adhesive film 15 does not proceed, and presses the tab wire 3 for a predetermined time with the pressing surface 26a. Therefore, the conductive adhesive film 15 temporarily fixes the tab wire 3 on the bus bar electrode 11 and the back electrode 13 when the binder resin exhibits fluidity and exhibits high adhesive strength.

  Next, as shown in FIG. 9, the plurality of solar cells 2 to which the tab wires 3 are temporarily fixed are transported and supported directly below the pair of upper and lower heating and pressing heads 28, and then are pressed by the pressing surface 28 a of the heating and pressing head 28. The tab wire 3 is finally press-bonded to the bus bar electrode 11 and the back electrode 13 of the solar battery cell 2 to cure the conductive adhesive film 15 (main press-bonding step).

  At this time, the plurality of solar cells 2 are configured so that the preceding solar cell 2 is moved up and down in synchronization with a pair of heating and pressing heads 28 provided above and below, so that the tab wire 3 is moved to a predetermined pressure ( For example, the pressure is about 3 MPa to 12 MPa. The heating and pressing head 28 is heated to a predetermined temperature (for example, about 180 to 220 ° C.) at which the conductive adhesive film 15 is cured. Therefore, the binder resin is thermally cured in the conductive adhesive film 15, and the tab wire 3 and the bus bar electrode 11 or the back electrode 13 are electrically and mechanically connected.

  By such a main pressure bonding, the conductive adhesive film 15 enters the concave portion 32 of the concave-convex portion 21 having the concave-convex angle α of 10 to 50 °, so that the connection reliability between the bus bar electrode 11 and the back electrode 13 can be improved. It becomes. Moreover, high conduction reliability can be obtained by increasing the particle trapping rate in the recess 32.

  When the tab wire 3 is finally crimped to the preceding solar cell 2 by the heating and pressing head 28, the pair of heating and pressing heads 28 are separated from the tab wire 3, and the subsequent solar cell 2 is connected to the pair of heating and pressing heads 28. It is transported directly below. In this way, the solar cells 2 are conveyed one by one directly below the heating and pressing head 28, and the tab wires 3 are sequentially bonded to the bus bar electrode 11 and the back electrode 13, and in series with the adjacent solar cells 2. It will be connected to.

  Thus, in the manufacturing process of the solar cell module 1, each of the bus bar electrode 11 and the back electrode 13 is connected to the tab wire 3 by the conductive adhesive film 15. Alternatively, either of Ag and Ag can be used, but by using a back surface Al current collecting electrode as the back surface electrode 13, it is not necessary to provide a conventional Ag electrode for solder connection, so the manufacturing process of the solar battery cell is shortened. , Have production technical advantages.

  In the manufacturing process of the solar cell module 1, the tab wire 3 having the concavo-convex portions 21 on both sides and the bus bar electrode 11 and the back electrode 13 are connected through the thermosetting resin. By applying the same pressure from both sides of the tab wire 3 to the tab wire 3 having the same shape on both sides, the stress strain in the solar cell 2 can be minimized and the cracking and warping of the solar cell 2 can be suppressed. .

  Moreover, since the solar cell module 1 is provided with the tab wire 3 of the front and back symmetrical shape which provided the uneven | corrugated | grooved part 21 in front and back both surfaces, when connecting the front and back both surfaces of the solar cell 2 simultaneously, the surface and back surface of the solar cell 2 Therefore, the generation of cracks and warpage of the solar battery cell 2 can be prevented. For example, even when the solar battery cell 2 is very thin, such an effect by suppressing the stress strain can be obtained.

  Moreover, the solar cell module 1 can express the light confinement effect by a scattered light by raising the uneven | corrugated angle (alpha) in the uneven | corrugated | grooved part 21 of the tab wire 3 to 10-50 degrees, and can improve electric power generation efficiency, and surface electrode Stable conduction reliability and connection reliability can be realized on the side and back electrode side.

  Although the present embodiment has been described above, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  In the present embodiment described above, the conductive adhesive film 15 is used as the adhesive resin material to connect each of the bus bar electrode 11 and the back electrode 13 and the tab wire 3, but other adhesive resin materials are used. You may make it use. When a non-conductive adhesive film is used as the adhesive resin material, conduction is achieved by directly contacting the convex portion 31 of the concave-convex portion 21 of the tab wire 3 with each of the bus bar electrode 11 and the back electrode 13. Moreover, it replaces with providing these adhesive films, and you may make it apply | coat paste-form adhesives, such as an electrically conductive paste and a nonelectroconductive paste, by appropriate thickness. By applying the conductive paste or the non-conductive paste at an appropriate thickness, the same effects as those of the conductive adhesive film 15 and the non-conductive adhesive film can be obtained.

  Moreover, in embodiment mentioned above, although the solar cell module 1 provided with the single-sided light reception type solar cell 2 was demonstrated, it was not limited to this, For example, the double-sided light reception type solar cell 2A shown in FIG. 10 was provided. It is good also as a solar cell module. Solar cell 2 </ b> A includes finger electrode 12 and bus bar 11 instead of back electrode 13. In addition, the solar battery module including the solar battery cell 2 </ b> A is provided with a surface cover 7 instead of the back sheet 8.

  Thus, also in the solar cell module provided with the double-sided light receiving solar cell 2A, the front and back surfaces of each solar cell 2A are connected simultaneously with the tab wire 3 by using the tab wires 3 having a symmetrical shape. In this case, the stress strain generated on the front surface side and the back surface side of the solar battery cell 2 can be suppressed to the minimum, so that the solar battery cell 2 can be prevented from being cracked or warped. Further, stable conduction reliability and connection reliability can be realized on the surface electrode (bus bar electrode 11, finger electrode 12) side and the back electrode 13 side. Furthermore, it is possible to further improve the power generation efficiency by providing the tab wire 3 having the uneven portions 21 formed on both sides.

<4. Example>
Next, specific examples of the present invention will be described. The scope of the present invention is not limited to the following examples. In this example, the tab wires shown in the following Examples 1 to 5 and Comparative Examples 1 to 5 were connected to the solar battery cell 2 as shown in FIG.

Example 1
First, one single-sided solar cell was prepared. An uncured conductive adhesive film (trade name: SP100 series, manufactured by Sony Chemical & Information Device Co., Ltd.) is applied to each of the bus bar electrode and the back electrode provided in the solar cell by a temporary sticking head, and the heating temperature is 180 ° C. Temporary pasting was performed by heating and pressurizing at 2 MPa for 15 seconds. Next, on the conductive adhesive film temporarily pasted on the bus bar electrode of the solar battery cell, and on the conductive adhesive film temporarily pasted on the back electrode of the solar battery cell, the concave-convex part of the concave-convex angle α = 10 °. The tab wires formed on both sides were crimped. The pressure bonding was performed by heating and pressing at 180 ° C. and a pressure of 2 MPa for 15 seconds using a pressure bonding head.

(Example 2)
The same process as in Example 1 was performed except that the tab line in which the uneven part having the uneven angle α = 20 ° was formed on both sides was used instead of the tab line in Example 1.

(Example 3)
The same processing as in Example 1 was performed except that the tab line in which the uneven part having the uneven angle α = 30 ° was formed on both surfaces was used instead of the tab line in Example 1.

Example 4
The same process as in Example 1 was performed except that the tab line in which the uneven part having the uneven angle α = 40 ° was formed on both sides was used instead of the tab line in Example 1.

(Example 5)
The same process as in Example 1 was performed except that the tab line in which the uneven part having the uneven angle α = 50 ° was formed on both sides was used instead of the tab line in Example 1.

(Comparative Example 1)
The same process as in Example 1 was performed except that the tab line in which the uneven part having the uneven angle α = 5 ° was formed on both sides was used instead of the tab line in Example 1.

(Comparative Example 2)
The same processing as in Example 1 was performed except that the tab line in which the uneven part with the unevenness angle α = 60 ° was formed on both sides was used instead of the tab line in Example 1.

(Comparative Example 3)
Instead of the tab line of Example 1, a tab line having an uneven part with an uneven angle α = 30 ° formed on one side was used. In the tab line connected to the bus bar electrode, the surface on which the uneven portion is formed is the light receiving surface side, and in the tab line connected to the back electrode, the surface on which the uneven portion is formed is opposed to the back electrode ([Table 1] "One side (1)"). Except this, the same processing as in Example 1 was performed.

(Comparative Example 4)
Instead of the tab line of Example 1, a tab line having an uneven part with an uneven angle α = 30 ° formed on one side was used. In the tab line connected to the bus bar electrode, the surface on which the uneven portion is formed is opposed to the bus bar electrode, and in the tab line connected to the back electrode, the surface opposite to the surface on which the uneven portion is formed is the back electrode. ("One side (2)" in [Table 1]). Except this, the same processing as in Example 1 was performed.

(Comparative Example 5)
The same process as in Example 1 was performed except that the tab line in Example 1 was used instead of the tab line having a planar shape on which both of the concave and convex portions were not formed.

<Evaluation of power generation efficiency>
The power generation efficiency (%) per photovoltaic cell after connecting the tab wires was measured with a solar simulator (model PVS1116i-M (JIS C8913) manufactured by Nisshinbo Mechatronics Inc.). A power generation efficiency of 16% or more was evaluated as ◎, 15.75 to 16% as ◯, 15.6 to 15.75% as Δ, and 15.6% or less as ×. The evaluation results are shown in [Table 1].

<Evaluation of connection reliability>
A 90 ° peel test (JIS K6854-1) was conducted to peel the tab wire from the conductive adhesive film bonded to each of the bus bar electrode and the back electrode in the 90 ° direction, and the peel strength (N / cm) was measured. Based on the measured peel strength, the connection reliability in each of the tab wire and the bus bar electrode and the tab wire and the back electrode was evaluated. The connection reliability was evaluated with a peel strength of 10 N / cm or more as ◎, 8 to 10 N / cm as ○, 6 to 8 N / cm as Δ, and 6 N / cm or less as ×. The evaluation results are shown in [Table 1].

<Evaluation of warpage amount>
With the solar cell placed on a flat surface (the convex surface due to warpage was placed on the lower side), the maximum height (mm) from the flat surface at the four corners of the solar battery cell was measured as the amount of warpage (mm). The amount of warpage was evaluated as 1 mm or less, ◯, 1 mm or more and less than 2.5 mm as Δ, and 2.5 mm or more as x. The evaluation results are shown in [Table 1].

<Comprehensive evaluation>
Of the evaluation items for power generation efficiency, connection reliability, and warpage, none of the evaluation results has a x evaluation result, and those that can be used without any problem in practice are evaluated as a comprehensive evaluation. What obtained the result was set as comprehensive evaluation x. The evaluation results of the comprehensive evaluation are shown in [Table 1].

  As shown in [Table 1], in Examples 1 to 5 in which the concavo-convex angle α is 10 ° or more and 50 ° or less, the incident light is incident on the concavo-convex portion having the concavo-convex angle α so that a favorable scattering angle is obtained. Scattered light could be obtained, and the light containment effect was expressed by the scattered light, and a high value in power generation efficiency could be obtained. In particular, in Example 3 in which the unevenness angle α was 30 °, the light confinement effect was best exhibited and the highest power generation efficiency could be obtained.

  Moreover, in Examples 1-5, since the uneven | corrugated angle (alpha) was 10 degrees or more and 50 degrees or less, since the filling amount of the binder resin of the electroconductive adhesive film which flows by heating and enters into a recessed part is sufficient, it is a tab. The connection reliability between the wire and the bus bar electrode, and the tab wire and the back electrode was good. In particular, in Examples 4 and 5 in which the concavo-convex angle α was set to 40 ° or more, it was possible to obtain a higher connection reliability by obtaining a larger amount of binder filling in the concave portion.

  Moreover, in Examples 1-5, since the front and back symmetrical shape tab line was provided, generation | occurrence | production of curvature was able to be suppressed to the minimum.

  Thus, in Examples 1-5, the comprehensive evaluation result which can be used practically without a problem from the evaluation result of power generation efficiency, connection reliability, and the amount of curvature was obtained.

  In particular, in Examples 2 to 4, since the concavo-convex angle α is set to 20 ° or more and 40 ° or less, the scattering angle of incident light can be set to a more favorable value, thereby further increasing the power generation efficiency. I was able to get it. Moreover, when the unevenness angle is 20 °, the filling amount of the binder resin of the conductive adhesive film that flows by heating and enters the recesses can be increased, and high connection reliability can be obtained.

  On the other hand, in Comparative Examples 1, 2, 4, and 5, the power generation efficiency was low. This is because, in Comparative Example 1, the unevenness angle α of the uneven portions formed on both sides of the tab line was too small, and in Comparative Example 2, the uneven angle α of the uneven portions formed on both sides of the tab line was too large. In Comparative Example 4, since the surface of the tab line in the planar shape is the light receiving surface side, in Comparative Example 5, both surfaces of the tab line are in the planar shape (concave / convex angle α = 0 °). This is probably because the containment effect could not be fully exhibited.

  In Comparative Examples 1 and 3 to 5, the connection reliability between the tab wire and the bus bar electrode, and the tab wire and the back electrode was not good. In Comparative Example 1, since the unevenness angle α is too small, it is considered that the connection reliability was not good because the amount of the binder resin filled in the conductive adhesive film that flowed by heating and entered the recess was not sufficient. .

  Further, in Comparative Example 3, since the surface of the tab line on the light receiving surface side that is connected to the bus bar electrode has a planar shape, the filling amount of the binder resin cannot be obtained at all on the tab line surface having the planar shape. The connection reliability between the tab line on the light receiving surface side and the bus bar electrode was not good. In Comparative Example 4, the surface of the tab wire on the back surface side that is connected to the back surface electrode has a planar shape, so that the amount of binder resin filling cannot be obtained at all on the tab wire surface having this planar shape. The connection reliability between the tab wire and the back electrode was not good.

  Further, in Comparative Example 5, since both sides of the tab wire have a planar shape, it is not possible to obtain a binder resin filling amount at all on the tab wire surface having the planar shape, either on the bus bar electrode side or on the back electrode side. Even connection reliability was not good.

  Further, in Comparative Examples 3 and 4, since the tab wires are connected to the front and back asymmetrical tab wires, the amount of warpage is caused because stress strain occurs at the bus bar electrode side and the back electrode side of the solar battery cells when the tab wires are connected. It is thought that it was big.

DESCRIPTION OF SYMBOLS 1 Solar cell module, 2 Solar cell, 3 Tab wire, 4 Strings, 5 matrix, 10 Photoelectric conversion element, 11 Bus bar electrode, 12 Finger electrode, 13 Back surface electrode, 15 Conductive adhesive film 21 Uneven part

In order to solve the above-described problem, a solar battery module according to the present invention includes, among a plurality of solar battery cells, another solar battery cell adjacent to one of the surface electrode of the predetermined solar battery cell and the predetermined solar battery cell. In the solar cell module in which the back electrode is connected by a tab line, the tab line is an unevenness in which a plurality of convex portions and concave portions that are continuous in the longitudinal direction are alternately provided in the width direction on both the front and back surfaces. Part is formed , is a front and back object shape with the center line as a boundary in the cross section in the width direction, one end of the surface electrode and the other end are connected to the back electrode via an adhesive resin material, An unevenness angle formed by a line segment connecting the apex of the convex part and the apex of the concave part adjacent to the convex part and a line segment connecting the apexes of the concave part adjacent to both sides of the convex part is more than 30 ° 4 ° Ri der hereinafter the recesses and protrusions of the tab line located on the surface side of the solar cell, and the concave and convex portions of the tab line located on the back side of the solar cell, the tab wire width direction the same position, the adhesive resin material is Ru nonconductive adhesive film der containing no conductive adhesive film or conductive particles containing conductive particles.

In addition, in order to solve the above-described problem, a method for manufacturing a solar cell module according to the present invention includes a predetermined surface electrode of a solar cell and one of the predetermined solar cells among a plurality of solar cells. In the method for manufacturing a solar cell module in which a back electrode of another adjacent solar battery cell is connected by a tab wire, the tab wire is connected to each of the front electrode and the back electrode of the solar cell via an adhesive resin material. The tab wire is formed with uneven portions formed by alternately providing a plurality of convex portions and concave portions continuous in the longitudinal direction on both the front and back surfaces of the tab wire in the width direction. A cross-sectional shape that is symmetrical with respect to the center line in the cross section, and a line segment connecting the apex of the convex part and the apex of the concave part adjacent to the convex part, and the apex of the concave part adjacent to both sides of the convex part Connect Uneven angles minutes and forms is at 30 ° to 40 °, and the concave and convex portions of the tab line located on the surface side of the solar cell, the recess of the tab line located on the back side of the solar cell and In the crimping step, one end of the tab wire is used as the front surface electrode, and the other end of the tab wire is used as the back electrode. As the adhesive resin material, a conductive adhesive film containing conductive particles or a non-conductive adhesive film not containing conductive particles is used .

Claims (4)

Among the plurality of solar cells, a solar cell module in which a surface electrode of a predetermined solar cell and a back electrode of another solar cell adjacent to one of the predetermined solar cells are connected by a tab wire In
The tab line is
On both the front and back surfaces, there are formed concavo-convex portions in which a plurality of convex portions and concave portions continuous in the longitudinal direction are alternately provided in the width direction,
One end thereof is connected to the front surface electrode, and the other end is connected to the back surface electrode via an adhesive resin material,
An unevenness angle formed by a line segment connecting the apex of the convex part and the apex of the concave part adjacent to the convex part and a line segment connecting the apexes of the concave part adjacent to both sides of the convex part is The solar cell module which is 10 degrees or more and 50 degrees or less.   The solar cell module according to claim 1, wherein the uneven angle is 20 ° or more and 40 ° or less.   The solar cell module according to claim 1, wherein the adhesive resin material is a conductive adhesive film containing conductive particles or a non-conductive adhesive film containing no conductive particles. Among the plurality of solar cells, a solar cell module in which a surface electrode of a predetermined solar cell and a back electrode of another solar cell adjacent to one of the predetermined solar cells are connected by a tab wire In the manufacturing method of
A crimping step of crimping the tab wire to each of the front electrode and the back electrode of the solar battery cell via an adhesive resin material;
The tab line is formed on both the front and back surfaces with a plurality of protrusions and recesses that are alternately provided in the width direction, and adjacent to the apex of the protrusions and the protrusions. The concavo-convex angle formed by the line segment connecting the apexes of the recesses and the line segment connecting the apexes of the recesses adjacent to both sides of the convex part is 10 ° or more and 50 ° or less,
In the crimping step, a method for manufacturing a solar cell module, wherein one end of the tab wire is connected to the front surface electrode, and the other end of the tab wire is connected to the back surface electrode via the adhesive resin material.

Images