JP5288790B2 - Solar cell module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell module in which a resin adhesive is disposed between a wiring material and a main surface of a solar cell, and a manufacturing method thereof.

  Solar cells are expected as a new energy source because they can directly convert clean and inexhaustible sunlight into electricity.

  Generally, the output per solar cell is about several watts. Therefore, when a solar cell is used as a power source for a house or a building, a solar cell module whose output is increased by connecting a plurality of solar cells is used. The solar cell module is configured by connecting a plurality of solar cells arranged according to the first direction to each other by a wiring material. The wiring material is usually soldered onto the main surface of the solar cell.

  Here, a technique has been proposed in which a resin adhesive that is thermoset at a temperature lower than the melting temperature of the solder is interposed between the wiring material and the main surface of the solar cell, and the wiring material is thermally bonded to the main surface of the solar cell. (For example, refer to Patent Document 1).

According to such a technique, the influence which the temperature change at the time of heat-bonding a wiring material has on a solar cell can be made small compared with the case where a wiring material is soldered.
JP 2005-101519 A

  Here, since the surface of the wiring material is generally flat, when the wiring material is thermally bonded to the main surface of the solar cell, pressure is uniformly applied to the resin adhesive. Therefore, the gas confined in the resin adhesive is easily removed from the end of the resin adhesive, but is difficult to remove from the center of the resin adhesive. Therefore, the gas confined in the center of the resin adhesive may remain as a lump (cavity). As described above, as a result of a reduction in the bonding area between the wiring material and the solar cell, there is a problem in that the current collection efficiency of the solar cell and the adhesiveness of the wiring material are reduced.

  Therefore, the present invention has been made in view of the above problems, and by promoting degassing from the resin adhesive, a solar cell module that improves the current collection efficiency of the solar cell and the adhesiveness of the wiring material, and It aims at providing the manufacturing method.

  The solar cell module according to the first feature of the present invention is a wiring member that electrically connects the first and second solar cells arranged in the first direction and the first and second solar cells. The first and second solar cells are formed on a main surface of the photoelectric conversion unit that generates a photogenerated carrier by receiving light, and collects the photogenerated carrier. And a wiring member is disposed along the first direction on the main surface of the first and second solar cells, and the wiring member and the main members of the first and second solar cells. Between the surfaces, a resin adhesive is disposed, and the outer periphery of the wiring member is formed in a convex shape toward the first and second solar cells in a cut surface substantially orthogonal to the first direction, A connection region that electrically connects the wiring member and the collecting electrode in a second direction substantially orthogonal to the first direction. Width, and gist larger than approximately half the width of the wiring member.

  In the first feature of the present invention, the current collecting electrode includes a plurality of fine wire electrodes that collect photogenerated carriers from the photoelectric conversion unit, and a bus bar electrode that collects photo generated carriers from the thin wire electrodes. Is formed along the first direction, the wiring member is disposed on the bus bar electrode, the resin adhesive includes a plurality of conductive particles, and the connection region is included in the resin adhesive. It may be formed by particles. Further, the bus bar electrode has a protruding portion formed in a convex shape toward the wiring material, the protruding portion is formed at an end portion in the second direction of the bus bar electrode, and the protruding portion is recessed into the wiring material. It is preferable.

  In the first feature of the present invention, the current collecting electrode includes a plurality of fine wire electrodes for collecting photogenerated carriers from the photoelectric conversion portion, and the connection region has a portion of the fine wire electrode embedded in the wiring material. May be formed.

  The manufacturing method of the solar cell module according to the second feature of the present invention includes a wiring for electrically connecting the first and second solar cells and the first and second solar cells arranged along the first direction. A method for manufacturing a solar cell module comprising a material, wherein first and first current collector electrodes for collecting photogenerated carriers are formed on a main surface of a photoelectric conversion unit that generates photogenerated carriers by receiving light. A process A for producing two solar cells, and a process B for thermocompression bonding the wiring material along the first direction via a resin adhesive on the main surfaces of the first and second solar cells, in the first direction The outer periphery of the wiring member is formed in a convex shape toward the first and second solar cells, and in step B, in the second direction substantially orthogonal to the first direction, the outer periphery of the wiring member is formed in the second direction substantially orthogonal to the first direction. The width of the connection area that electrically connects the And gist to be larger than approximately half of.

  According to such a method for manufacturing a solar cell module, the outer periphery of the wiring member is formed in a convex shape toward the current collecting electrode. For this reason, in the thermocompression bonding process of the wiring material, first, pressure is applied to the central portion in the second direction of the resin adhesive, and then pressure is gradually applied to the end portion. That is, the end portion of the resin adhesive is pressed with a time delay from the central portion.

  Therefore, the gas confined in the resin adhesive is gradually pushed out from the central portion to the end portion. That is, the degassing of the resin adhesive is gradually performed from the central portion to the end portion. Thus, since deaeration of the resin adhesive is promoted, it is possible to suppress a lump of gas remaining as a cavity in the resin adhesive after the thermocompression bonding process of the wiring member.

  In the thermocompression bonding process of the wiring material, since the width of the connection region is made larger than approximately half of the width of the wiring material, the electrical connection between the wiring material and the collecting electrode can be sufficiently ensured.

  In the second feature of the present invention, the resin adhesive includes a plurality of conductive particles, and in step B, the particle size of the particles contained in the resin adhesive is set to a predetermined particle size or more, thereby connecting. The width of the region may be larger than approximately half of the width of the wiring material.

  In the second feature of the present invention, in step B, the width of the connection region is increased by setting the pressure at the time of thermocompression bonding on the main surfaces of the first and second solar cells to a predetermined pressure or higher. You may make it larger than about half of the width | variety of a wiring material.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell module which improved the current collection efficiency of the solar cell, and the adhesiveness of the wiring material by accelerating | stimulating the deaeration from a resin adhesive, and its manufacturing method can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

1. First embodiment (schematic configuration of solar cell module)
A schematic configuration of the solar cell module 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an enlarged side view of a solar cell module 100 according to the present embodiment.

  The solar cell module 100 includes a solar cell string 1, a light receiving surface side protective material 2, a back surface side protective material 3, and a sealing material 4. The solar cell module 100 is configured by sealing the solar cell string 1 between the light-receiving surface side protective material 2 and the back surface side protective material 3.

  The solar cell string 1 includes a plurality of solar cells 10, a wiring material 11, and a resin adhesive 12. The solar cell string 1 is configured by connecting a plurality of solar cells 10 arranged in the first direction to each other by a wiring material 11.

  Solar cell 10 has a light receiving surface on which sunlight is incident and a back surface provided on the opposite side of the light receiving surface. The light receiving surface and the back surface are the main surfaces of the solar cell 10. Current collecting electrodes are formed on the light receiving surface and the back surface of the solar cell 10. The configuration of the solar cell 10 will be described later.

  The wiring member 11 is joined to the collector electrode formed on the light receiving surface of one solar cell 10 and the collector electrode formed on the back surface of another solar cell 10 adjacent to the one solar cell. . Thereby, one solar cell 10 and the other solar cell 10 are electrically connected. The wiring material 11 includes a thin plate-like low resistance (copper or the like) and a soft conductor (eutectic solder or the like) plated on the surface of the low resistance.

  The resin adhesive 12 is disposed between the wiring material 11 and the solar cell 10. That is, the wiring material 11 is joined to the solar cell 10 via the resin adhesive 12. The resin adhesive 12 is preferably cured at a temperature not higher than the melting point of the eutectic solder, that is, not higher than about 200 ° C. Examples of the resin adhesive 12 include a two-component reaction type adhesive in which a curing agent is mixed with an epoxy resin, an acrylic resin, or a urethane resin in addition to a thermosetting resin adhesive such as an acrylic resin or a highly flexible polyurethane type. An agent or the like can be used. In this embodiment, a strip-shaped film sheet adhesive mainly composed of an epoxy resin is used as the resin adhesive 12.

  The resin adhesive 12 includes a plurality of conductive particles. As the conductive particles, nickel, nickel with gold coating, or the like can be used.

  The light receiving surface side protective material 2 is disposed on the light receiving surface side of the sealing material 4 and protects the surface of the solar cell module 100. As the light-receiving surface side protective material 2, glass having translucency and water shielding properties, translucent plastic, or the like can be used.

  The back surface side protective material 3 is disposed on the back surface side of the sealing material 4 and protects the back surface of the solar cell module 100. As the back surface side protective material 3, a resin film such as PET (Polyethylene Terephthalate), a laminated film having a structure in which an Al foil is sandwiched between resin films, and the like can be used.

  The sealing material 4 seals the solar cell string 1 between the light receiving surface side protective material 2 and the back surface side protective material 3. As the sealing material 4, a translucent resin such as EVA, EEA, PVB, silicon, urethane, acrylic, or epoxy can be used.

  An Al frame (not shown) can be attached to the outer periphery of the solar cell module 100 having the above configuration.

(Configuration of solar cell)
Next, the configuration of the solar cell 10 will be described with reference to FIG. FIG. 2 is a plan view of the solar cell 10.

  As shown in FIG. 2, the solar cell 10 includes a photoelectric conversion unit 20, a thin wire electrode 30, and a bus bar electrode 40.

  The photoelectric conversion unit 20 generates photogenerated carriers by receiving sunlight. The photogenerated carrier refers to holes and electrons generated by absorption of sunlight into the photoelectric conversion unit 20. The photoelectric conversion unit 20 has an n-type region and a p-type region inside, and a semiconductor junction is formed at the interface between the n-type region and the p-type region. The photoelectric conversion unit 20 can be formed using a semiconductor substrate made of a crystalline semiconductor material such as single crystal Si or polycrystalline Si, or a semiconductor material such as a compound semiconductor material such as GaAs or InP. The photoelectric conversion unit 20 has a structure in which the characteristics of the heterojunction interface are improved by sandwiching a substantially intrinsic amorphous silicon layer between the single crystal silicon substrate and the amorphous silicon layer, that is, a so-called HIT. You may have a structure.

  The thin wire electrode 30 is an electrode that collects photogenerated carriers from the photoelectric conversion unit 20. As shown in FIG. 2, the thin wire electrode 30 is formed in a line shape along a second direction substantially orthogonal to the first direction. A plurality of thin wire electrodes 30 are formed over substantially the entire light receiving surface of the photoelectric conversion unit 20. The fine wire electrode 30 can be formed using a resin-type conductive paste using a resin material as a binder and conductive particles such as silver particles as a filler. As shown in FIG. 1, the thin wire electrodes are similarly formed on the light receiving surface and the back surface of the photoelectric conversion unit 20.

  The bus bar electrode 40 is an electrode that collects photogenerated carriers from the plurality of thin wire electrodes 30. As shown in FIG. 2, the bus bar electrode 40 is formed along the first direction so as to intersect the thin wire electrode 30. The bus bar electrode 40 can be formed using a resin-type conductive paste using a resin material as a binder and conductive particles such as silver particles as a filler. As shown in FIG. 1, the bus bar electrode is also formed on the light receiving surface of the photoelectric conversion unit 20.

  Here, the number of bus bar electrodes 40 can be set to an appropriate number in consideration of the size of the photoelectric conversion unit 20 and the like. The solar cell 10 according to this embodiment includes two bus bar electrodes 40. Therefore, the plurality of thin wire electrodes 30 and the bus bar electrodes 40 are formed in a lattice shape on the light receiving surface and the back surface of the photoelectric conversion unit 20.

  Next, as an example of the configuration of the solar cell 10, a case where the photoelectric conversion unit 20 has a HIT structure will be described with reference to FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG.

  As shown in FIG. 3, the photoelectric conversion unit 20 includes an ITO film 20a, a p-type amorphous silicon layer 20b, an i-type amorphous silicon layer 20c, an n-type single crystal silicon substrate 20d, and an i-type amorphous silicon layer. 20e, an n-type amorphous silicon layer 20f and an ITO film 20g.

  A p-type amorphous silicon layer 20b is formed on the light-receiving surface side of the n-type single crystal silicon substrate 20d via an i-type amorphous silicon layer 20c. An ITO film 20a is formed on the light receiving surface side of the p-type amorphous silicon layer 20b. On the other hand, an n-type amorphous silicon layer 20f is formed on the back side of the n-type single crystal silicon substrate 20d via an i-type amorphous silicon layer 20e. An ITO film 20g is formed on the back side of the n-type amorphous silicon layer 20f.

  The fine wire electrode 30 and the bus bar electrode 40 are formed on the light receiving surface side of the ITO film 20a and the back surface side of the ITO film 20g, respectively.

  The solar cell module 100 having the solar cell 10 having such a configuration is called a HIT solar cell module.

(Configuration of solar cell string)
Next, the configuration of the solar cell string 1 will be described with reference to FIGS. 4 and 5. FIG. 4 shows a state in which the wiring member 11 is disposed on the bus bar electrode 40 shown in FIG. FIG. 5 is an enlarged cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 4, the resin adhesive 12 is disposed on the bus bar electrode 40 formed in a line shape along the first direction. The width of the resin adhesive 12 in the second direction is larger than the width of the bus bar electrode 40 in the second direction.

  Further, the wiring member 11 is disposed along the bus bar electrode 40 on the resin adhesive 12. That is, the wiring material 11 is disposed along the first direction on the main surface of the solar cell 10. The width of the wiring member 11 in the second direction is substantially equal to the width of the bus bar electrode 40.

  As described above, the bus bar electrode 40, the resin adhesive 12, and the wiring material 11 are sequentially arranged on the photoelectric conversion unit 20. The wiring member 11 and the bus bar electrode 40 are electrically connected.

  As shown in FIG. 5, the wiring member 11 includes a low resistance body 11a, a soft conductor 11b, and a soft conductor 11c. The soft conductor 11b is located between the low resistance body 11a and the solar cell 10, and the soft conductor 11c is located on the low resistance body 11a. The width of the wiring member 11 in the second direction is W2.

  In the third direction substantially perpendicular to the main surface of the solar cell 10, the thickness T1 of the soft conductor 11b decreases from the center in the second direction toward the end in the second direction. Therefore, the outer periphery of the wiring member 11 is formed in a convex shape toward the solar cell 10 on the cut surface substantially orthogonal to the first direction. As shown in FIG. 5, the wiring material 11 has the same external shape on the light receiving surface side and the back surface side.

  A resin adhesive 12 is inserted between the wiring member 11 and the solar cell 10. The resin adhesive 12 includes a plurality of particles 13 having conductivity. As shown in FIG. 5, the plurality of particles 13 are embedded in the soft conductor 11 b, the particles 13 embedded in the soft conductor 11 b and the bus bar electrode 40, or embedded in the resin adhesive 12. Particles 13 are included.

  The wiring member 11 and the bus bar electrode 40 are electrically connected by the particle 13 embedded in the soft conductor 11 b and the particle 13 sandwiched between the soft conductor 11 b and the bus bar electrode 40.

  In the present embodiment, a region where the soft conductor 11b and the bus bar electrode 40 are electrically connected is referred to as a connection region C. The connection region C is formed by a plurality of particles 13. Therefore, the connection region C is a region in which the distance between the soft conductor 11b and the bus bar electrode 40 is substantially equal to or smaller than the particle size of the particle 13 in a cut surface substantially orthogonal to the first direction.

  Here, the width W1 of the connection region C in the second direction is larger than approximately half of the width W2 of the wiring member 11. That is, at both ends of the connection region C, the interval between the particles 13 sandwiched between the soft conductor 11b and the bus bar electrode 40 is larger than about half of the width W2 of the wiring member 11.

(Method for manufacturing solar cell module)
Next, a method for manufacturing the solar cell module 100 according to this embodiment will be described.

  First, a 100 mm square n-type single crystal silicon substrate 20d is anisotropically etched with an alkaline aqueous solution to form fine irregularities on the light receiving surface of the n-type single crystal silicon substrate 20d. Further, the light receiving surface of the n-type single crystal silicon substrate 20d is washed to remove impurities.

  Next, an i-type amorphous silicon layer 20c and a p-type amorphous silicon layer 20b are sequentially stacked on the light-receiving surface side of the n-type single crystal silicon substrate 20d using a CVD (chemical vapor deposition) method. Similarly, an i-type amorphous silicon layer 20e and an n-type amorphous silicon layer 20f are sequentially stacked on the back side of the n-type single crystal silicon substrate 20d.

  Next, an ITO film 20a is formed on the light receiving surface side of the p-type amorphous silicon layer 20b by using a PVD (physical vapor deposition) method. Similarly, an ITO film 20g is formed on the back side of the n-type amorphous silicon layer 20f. Thus, the photoelectric conversion unit 20 is manufactured.

  Next, an epoxy thermosetting silver paste is arranged in a predetermined pattern on the light receiving surface and the back surface of the photoelectric conversion unit 20 by using a printing method such as a screen printing method or an offset printing method. As shown in FIG. 2, the predetermined pattern is a lattice shape formed by two bus bar electrodes 40 extending along the first direction and a plurality of thin wire electrodes 30 extending along the second direction. Say.

  The silver paste is heated under predetermined conditions to volatilize the solvent, and then further dried for about the main drying. Thus, the solar cell 10 is produced.

  Next, as shown in FIG. 6, the wiring member 11 is thermocompression bonded onto the bus bar electrode 40 through the resin adhesive 12 including a plurality of particles 13. Thereby, the wiring material 11 and the solar cell 10 are mechanically and electrically connected. Specifically, first, the resin adhesive 12 and the wiring member 11 are sequentially arranged on the bus bar electrodes 40 formed on the light receiving surface and the back surface of the photoelectric conversion unit 20. Next, the wiring member 11 is pressed against the solar cell 10 by the heater block 50 heated to about 180 ° C. for about 15 seconds. As a result, the plurality of particles 13 are embedded in the soft conductor 11 b and are sandwiched between the soft conductor 11 b and the bus bar electrode 40.

  The Mohs hardness of nickel, which is the material of the particles 13, solder, which is the material of the soft conductor 11b, and silver paste, which is the material of the bus bar electrode 40, is 3.5, 1.8, and 2.5, respectively. . Therefore, the particles 13 are embedded in the soft conductor 11b by pressing the wiring member 11 against the solar cell 10.

  Here, the electrical connection between the wiring member 11 and the solar cell 10 is made by a connection region C in which the distance between the soft conductor 11b and the bus bar electrode 40 is a region that is substantially equal to or smaller than the particle size of the particles 13. .

  In the present embodiment, in the second direction, the width W1 of the connection region C is set to be larger than approximately half of the width W2 of the wiring material 11.

  Specifically, in order to make the width W1 of the connection region C larger than approximately half of the width W2 of the wiring member 11, the following three methods can be employed.

  The first method is a method in which the pressure when pressing the wiring member 11 against the solar cell 10 by the heater block 50 is set to a predetermined value or more.

  The second method is a method in which the particle size of the particles 13 included in the resin adhesive 12 is set to a predetermined particle size or more.

  The third method is a method of reducing the curvature of the outer periphery of the wiring member 11 at the cut surface substantially orthogonal to the first direction. That is, this is a technique using a wiring material 11 that is nearly flat. Specifically, the curvature of the outer periphery of the wiring member 11 is controlled by changing the speed at which the low resistance body 11a is pulled up from the plating bath of the soft conductor 11b or the shape of a die used for lifting from the plating bath. To do.

  In the actual crimping process, the width W1 of the connection region C is made to be the width W2 of the wiring member 11 by interlocking the pressure for pressing the heater block 50, the particle size of the particles 13 and the curvature of the outer periphery of the wiring member 11 as one unit. Larger than about half of

  Thus, the solar cell string 1 is created.

  Next, an EVA (sealing material 4) sheet, a solar cell string 1, an EVA (sealing material 4) sheet, and a PET sheet (back surface side protection material 3) are sequentially placed on the glass substrate (light-receiving surface side protection material 2). Laminate to make a laminate.

  Next, the laminated body is temporarily pressure-bonded by thermocompression bonding in a vacuum atmosphere, and then EVA is completely cured by heating under a predetermined condition. Thus, the solar cell module 100 is manufactured.

  Note that a terminal box, an Al frame, or the like can be attached to the solar cell module 100.

(Function and effect)
According to the manufacturing method of the solar cell module 100 according to the present embodiment, in the step of thermocompression bonding the wiring material 11 on the main surface of the solar cell 10 via the resin adhesive 12 including the particles 13, The width W1 of the connection region C that is electrically connected to the bus bar electrode 40 is set to be larger than substantially half of the width W2 of the wiring member 11. The outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40 at a cut surface substantially orthogonal to the first direction.

  Thus, the outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40. Therefore, in the thermocompression bonding step, first, pressure is applied to the central portion in the second direction of the resin adhesive 12, and then pressure is gradually applied to the end portion. That is, the end of the resin adhesive 12 is pressed with a time delay from the center.

  Therefore, the gas confined in the resin adhesive 12 is gradually pushed out from the central portion to the end portion. That is, the degassing of the resin adhesive 12 is gradually performed from the central portion to the end portion. Thus, since deaeration of the resin adhesive 12 is accelerated | stimulated, it can suppress that the lump of gas remains in the resin adhesive 12 as a cavity after a thermocompression bonding process.

  Further, in the thermocompression bonding step, the width W1 of the connection region C is set to be larger than substantially half of the width W2 of the wiring material 11. Therefore, electrical connection between the wiring member 11 and the solar cell 10 (bus bar electrode 40) can be sufficiently ensured.

  As a result, the current collection efficiency of the solar cell 10 and the adhesion of the wiring member 11 to the solar cell 10 (bus bar electrode 40) can be improved.

  In the present embodiment, the connection region C is formed by a plurality of particles 13. Therefore, the connection region C is a region in which the distance between the soft conductor 11b and the bus bar electrode 40 is substantially equal to or smaller than the particle size of the particle 13 in a cut surface substantially orthogonal to the first direction.

  Therefore, by setting the pressure for pressing the wiring member 11 against the solar cell 10 by the heater block 50 to a predetermined value or more, the width W1 of the connection region C can be made larger than substantially half of the width W2 of the wiring member 11. By pressing the wiring member 11 against the solar cell 10 (bus bar electrode 40) with a large pressure, the width W1 of the connection region C can be increased as a result of the deformation of the soft conductor 11b.

  Further, by setting the particle size of the particles 13 included in the resin adhesive 12 to be equal to or larger than a predetermined particle size, the width W1 of the connection region C can be made larger than approximately half of the width W2 of the wiring member 11. This is because the connection region C is a region in which the distance between the soft conductor 11b and the solar cell 10 (bus bar electrode 40) is substantially equal to or smaller than the particle size of the particles 13. Thus, by increasing the particle size of the particles 13, the width W1 of the connection region C can be increased.

  Further, by reducing the curvature of the outer periphery of the wiring member 11 at the cut surface substantially orthogonal to the first direction, the width W1 of the connection region C can be made larger than substantially half of the width W2 of the wiring member 11. This is because if the wiring member 11 is close to a flat shape, the width of the region where the distance between the wiring member 11 and the solar cell 10 (bus bar electrode 40) is substantially equal to or smaller than the particle size of the particle 13 can be increased.

2. Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings. The difference between the present embodiment and the first embodiment is that the bus bar electrode has a protrusion protruding toward the wiring member. Therefore, in the following, description of the same or similar parts as in the first embodiment will be omitted. (Configuration of solar cell string)
The configuration of the solar cell string 1 according to this embodiment will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 7, the bus bar electrode 40 according to the present embodiment has a protrusion 40 a formed in a convex shape toward the wiring member 11. The protrusion 40a is formed at the end of the bus bar electrode 40 in the second direction. The protrusion 40 a is recessed into the soft conductor 11 b included in the wiring material 11. The height of the protrusion 40a in the third direction is preferably substantially equal to the thickness T1 of the soft conductor 11b. Such a protrusion 40a can be formed by the following first to third methods.

  The first method is a method of increasing the interval between the frame for fixing the screen and the photoelectric conversion unit 20 when the bus bar electrode 40 is formed on the photoelectric conversion unit 20 by the screen printing method.

  First, the photoelectric conversion unit 20 and the frame are fixed at a predetermined interval. Next, a silver paste is extruded onto the photoelectric conversion unit 20 from the opening of the screen. At this time, the screen is pushed up to the photoelectric conversion unit 20 side by the squeegee and then moved up to the original position.

  Here, the screen has a portion in which the opening portion of the wire stretched in a lattice shape on the frame is crushed by the emulsion, and a portion in which the emulsion is lost in the shape of the bus bar electrode 40. Therefore, when the screen splashes, the silver paste is lifted by being pulled by the screen at the boundary between the portion where the emulsion is formed and the portion where the emulsion is lost. As a result, a protrusion 40 a is formed at the end of the bus bar electrode 40. Such protrusions 40a can be formed higher as the screen rises larger, that is, as the distance between the frame for fixing the screen and the photoelectric conversion unit 20 increases.

  The second method is a method of increasing the printing speed when the bus bar electrode 40 is formed on the photoelectric conversion unit 20 by the screen printing method. The printing speed is a moving speed of the squeegee when the silver paste is pushed out from the opening portion of the screen onto the photoelectric conversion unit 20.

  Increasing the speed of the squeegee moves up the screen faster. As the screen pops up quickly, the silver paste is pulled to the screen at the boundary between the part where the emulsion is formed and the part where the emulsion is missing. As a result, a protrusion 40 a is formed at the end of the bus bar electrode 40. Such a protrusion 40a can be formed higher as the screen splashes faster, that is, as the printing speed increases.

  The third method is a method of increasing the viscosity of the silver paste that is a material of the bus bar electrode 40 when the bus bar electrode 40 is formed on the photoelectric conversion unit 20 by the screen printing method. As described above, the silver paste is lifted together with the screen at the boundary between the portion where the emulsion is formed and the portion where the emulsion is missing. At this time, the higher the viscosity of the silver paste, the easier it is to be pulled by the screen. That is, the higher the viscosity of the silver paste, the higher the protrusion 40a can be formed.

  Also in this embodiment, as shown in FIG. 7, the outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40, and the width W1 of the connection region C in the second direction is the wiring member. 11 is greater than approximately half of the width W2.

(Function and effect)
In the solar cell module 100 according to the present embodiment, the outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40 at a cut surface substantially orthogonal to the first direction, as in the first embodiment. The width W1 of the connection region C is larger than substantially half of the width W2 of the wiring member 11.

  Therefore, in the step of connecting the wiring member 11, the degassing of the resin adhesive 12 can be promoted, and the wiring member 11 and the bus bar electrode 40 can be electrically connected in the connection region C.

  Furthermore, in the solar cell module 100 according to the present embodiment, the bus bar electrode 40 has a protruding portion 40 a formed in a convex shape toward the wiring member 11. The protrusion 40 a is formed at the end of the bus bar electrode 40 in the second direction and is recessed into the wiring member 11.

  As described above, the protrusion 40 a is recessed into the wiring material 11, whereby the mechanical connection strength between the wiring material 11 and the bus bar electrode 40 can be improved and the electrical connection between the wiring material 11 and the bus bar electrode 40 is achieved. Can be improved. As a result, the current collection efficiency of the solar cell 10 and the adhesiveness of the wiring material 11 can be further improved.

3. Third Embodiment Next, a third embodiment of the present invention will be described with reference to the drawings. The difference between the present embodiment and the first embodiment is that the solar cell according to the present embodiment does not include a bus bar electrode as a collecting electrode. Therefore, in the following description, description of the same or similar parts as those in the first embodiment is omitted.

(Schematic configuration of solar cell module)
A schematic configuration of the solar cell module 200 according to the present embodiment will be described with reference to FIG. FIG. 8 is an enlarged side view of the solar cell module 200 according to the present embodiment.

  The solar cell module 200 is configured by sealing the solar cell string 60 with the sealing material 4 between the light receiving surface side protective material 2 and the back surface side protective material 3.

  The solar cell string 60 includes a plurality of solar cells 70, a wiring material 11, and a resin adhesive 72. The solar cell string 60 is configured by connecting a plurality of solar cells 70 arranged according to the first direction to each other by the wiring member 11.

  The resin adhesive 72 is a strip-shaped film sheet adhesive mainly composed of an epoxy resin. However, the resin adhesive 72 does not include conductive particles.

  Other configurations are the same as those in the first embodiment.

(Configuration of solar cell)
Next, the configuration of the solar cell 70 will be described with reference to FIG. FIG. 9 is a plan view of the solar cell 70 on the light receiving surface side.

  As shown in FIG. 9, the solar cell 70 includes a photoelectric conversion unit 20 and a thin wire electrode 30. The solar cell 70 does not include a bus bar electrode as a collecting electrode.

  Other configurations are the same as those in the first embodiment.

(Configuration of solar cell string)
Next, the configuration of the solar cell string 60 will be described with reference to FIGS. 10 to 12. FIG. 10 shows a state in which the wiring member 11 is disposed on the solar cell 70. FIG. 11 is an enlarged cross-sectional view taken along the line DD in FIG. 12 is an enlarged cross-sectional view taken along the line E-E in FIG. 10.

  As shown in FIG. 10, two resin adhesives 72 are arranged on the solar cell 70 along the first direction. Further, the wiring member 11 is disposed along the first direction on the resin adhesive 72. The width of the wiring material 11 in the second direction is narrower than the width of the resin adhesive 72.

  Thus, on the solar cell 70, the resin adhesive 72 and the wiring material 11 are arrange | positioned in order.

  As shown in FIG. 11, the wiring member 11 includes a low resistance body 11a, a soft conductor 11b, and a soft conductor 11c. The width of the wiring member 11 in the second direction is W2.

  In the third direction substantially perpendicular to the main surface of the solar cell 70, the thickness T1 of the soft conductor 11b decreases from the center in the second direction toward the end. That is, the outer periphery of the wiring member 11 is formed in a convex shape toward the solar cell 70 on the cut surface substantially orthogonal to the first direction.

  As shown in FIG. 12, the upper end portion of the fine wire electrode 30 is embedded in the soft conductor 11b. That is, a part of the thin wire electrode 30 is embedded in the wiring material 11. Thereby, the thin wire electrode 30 and the wiring material 11 are electrically and mechanically connected.

  In the present embodiment, as shown in FIGS. 11 and 12, a region where the thin wire electrode 30 and the soft conductor 11 b are electrically connected is referred to as a connection region F. The connection region F is formed by embedding a part of the thin wire electrode 30 in the wiring material 11.

  Here, the width W1 of the connection region F in the second direction is larger than substantially half of the width W2 of the wiring member 11, as shown in FIG.

(Method for manufacturing solar cell module)
Next, a method for manufacturing the solar cell module 200 according to this embodiment will be described.

  First, the photoelectric conversion unit 20 similar to that described in the first embodiment is manufactured.

  Next, using a printing method such as a screen printing method or an offset printing method, a plurality of epoxy thermosetting silver pastes are provided along the second direction on the light receiving surface and the back surface of the photoelectric conversion unit 20. Apply. Next, the silver paste is heated under predetermined conditions to volatilize the solvent, and then further heated to perform the main drying. In this way, the thin wire electrode 30 is formed. Thus, the solar cell 70 is manufactured.

  Next, the wiring member 11 is thermocompression-bonded on the solar cell 70 via the resin adhesive 72. Thereby, the wiring material 11 and the solar cell 70 are mechanically and electrically connected. Specifically, first, the resin adhesive 72 and the wiring material 11 are sequentially arranged on the light receiving surface and the back surface of the photoelectric conversion unit 20. Next, the wiring member 11 is pressed against the solar cell 70 for about 15 seconds by a heater block heated to about 180 ° C.

  Electrical connection between the wiring member 11 and the solar cell 70 is made by a region where a part of the thin wire electrode 30 is embedded in the wiring member 11, that is, a connection region F. Here, in the present embodiment, the width W1 of the connection region F in the second direction is set to be larger than substantially half of the width W2 of the wiring member 11.

  Specifically, in order to make the width W1 of the connection region F larger than substantially half of the width W2 of the wiring member 11, the following two methods can be employed.

  The first method is a method in which the pressure for pressing the wiring member 11 against the solar cell 70 by the heater block 50 is set to a predetermined value or more.

  The second method is a method of reducing the curvature of the outer periphery of the wiring member 11 at the cut surface substantially orthogonal to the first direction. That is, this is a technique using a wiring material 11 that is nearly flat. Specifically, the curvature of the outer periphery of the wiring member 11 is controlled by changing the speed at which the low resistance body 11a is pulled up from the plating bath of the soft conductor 11b or the shape of a die used for lifting from the plating bath. To do.

  In the actual crimping process, the pressure W for pressing the heater block 50 and the curvature of the wiring member 11 are linked together to make the width W1 of the connection region F larger than substantially half of the width W2 of the wiring member 11. . Thus, the solar cell string 60 is manufactured.

  Next, an EVA (sealing material 4) sheet, a solar cell string 60, an EVA (sealing material 4) sheet, and a PET sheet (back surface side protection material 3) are sequentially placed on the glass substrate (light-receiving surface side protection material 2). Laminate to make a laminate.

  Next, the laminated body is temporarily pressure-bonded by thermocompression bonding in a vacuum atmosphere, and then EVA is completely cured by heating under a predetermined condition. Thus, the solar cell module 200 is manufactured.

  Note that a terminal box, an Al frame, or the like can be attached to the solar cell module 200.

(Function and effect)
According to the method for manufacturing the solar cell module 200 according to the present embodiment, in the step of thermocompression bonding the wiring material 11 on the main surface of the solar cell 70 via the resin adhesive 72, the wiring material 11 and the fine wire electrode 30 The width W1 of the connection region F that electrically connects the two is made larger than substantially half of the width W2 of the wiring member 11. The outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40 at a cut surface substantially orthogonal to the first direction.

  Thus, the outer periphery of the wiring member 11 is formed in a convex shape toward the bus bar electrode 40. Therefore, in the thermocompression bonding step, first, pressure is applied to the center portion in the second direction of the resin adhesive 72, and then pressure is gradually applied to the end portions. Accordingly, the degassing of the resin adhesive 72 is gradually performed from the central portion to the end portion. As described above, as a result of the degassing of the resin adhesive 72 being promoted, it is possible to suppress the lump of gas remaining in the resin adhesive 72 as a cavity after the thermocompression bonding step.

  Further, in the thermocompression bonding process, the width W1 of the connection region F is set to be larger than substantially half of the width W2 of the wiring member 11. Therefore, the electrical connection between the wiring member 11 and the solar cell 70 (thin wire electrode 30) can be sufficiently ensured.

  As a result, the current collection efficiency of the solar cell 70 and the adhesion of the wiring member 11 to the solar cell 70 (thin wire electrode 30) can be improved.

(Other embodiments)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  Moreover, in the said embodiment, although the multiple thin wire electrode 30 was formed on the back surface of the photoelectric conversion part 20, you may form so that the back surface whole surface may be covered. The present invention does not limit the shape of the thin wire electrode 30 formed on the back surface of the photoelectric conversion unit 20.

  Moreover, in the said 1st Embodiment, although the width | variety in the 2nd direction of the resin adhesive 12 was made larger than the width | variety in the 2nd direction of the bus-bar electrode 40, you may be substantially equivalent or small.

  Moreover, in the said 2nd Embodiment, although the projection part 40a was formed smaller than the thickness T1 of the soft conductor 11b, you may form the height of the projection part 40a larger than the thickness T1 of the soft conductor 11b. That is, the protrusion 40a may reach the low resistance body 11a.

  Moreover, in the said 3rd Embodiment, although the width | variety in the 2nd direction of the resin adhesive 72 was made larger than the width | variety in the 2nd direction of the wiring material 11, you may be substantially equivalent or small.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  Examples of solar cells used in the solar cell module according to the present invention will be specifically described below, but the present invention is not limited to those shown in the following examples, and the gist thereof is not changed. However, it can be implemented with appropriate modifications.

（実施例）
まず、寸法１００ｍｍ角のｎ型単結晶シリコン基板を用いて光電変換部を作製した。 Examples 1 to 8 and Comparative Examples 1 to 5 were produced based on the following Table 1.

(Example)
First, a photoelectric conversion part was manufactured using an n-type single crystal silicon substrate having a size of 100 mm square.

  A thin wire electrode and a bus bar electrode were formed in a comb shape on the light receiving surface and the back surface of the photoelectric conversion unit by screen printing using an epoxy thermosetting silver paste. The thickness (height) of the bus bar electrode was 50 μm and the width was 1.5 mm. In this way, a solar cell was produced.

  Next, a wiring material was prepared by plating SnAgCu-based solder into a convex shape on the upper and lower surfaces of a flat copper foil having a width of 1.5 mm. Specifically, as shown in Table 1, the thicknesses of the central part and the end part in the width direction of the wiring material were varied for each example.

  The thickness of the wiring material was controlled by changing the shape of the die, which is a member for pulling up the copper foil from the solder bath.

  Next, an epoxy resin adhesive was applied to the bus bar electrode formed on the light receiving surface of one solar cell and the bus bar electrode formed on the back surface of another adjacent solar cell. As the epoxy resin-based adhesive, one obtained by kneading about 50000 nickel particles in 1 mm 3 of epoxy resin was used. The particle size of the nickel particles was set for each example as shown in Table 1.

  Next, a wiring material was placed on the epoxy resin adhesive.

  Next, it heated for 60 second, pressing from the upper and lower sides of a wiring material with the metal head heated at 200 degreeC. The pressurizing force of the metal head was set for each example as shown in Table 1.

  The solar cell which concerns on Examples 1-8 was produced as mentioned above.

(Comparative example)
The solar cell string which concerns on Comparative Examples 1-5 of this invention was produced based on the said Table 1. The difference in the manufacturing method between the comparative example and the above example is the setting of the thickness between the central portion and the end portion in the width direction of the wiring material, the particle size of the nickel particles, and the pressure applied to the metal head.

  Other steps are the same as those in the above embodiment.

(Output measurement)
Hereinafter, the results of measuring the outputs of the solar cells according to Examples 1 to 8 and Comparative Examples 1 to 5 before and after thermally bonding the wiring materials will be examined with reference to Table 1.

  In Table 1, the output ratio is a relative value of the solar cell output after the wiring material is thermally bonded to the solar cell output before the wiring material is thermally bonded.

  Moreover, about Examples 1-8 and Comparative Examples 1-5, the width | variety of the connection area | region where a wiring material and a bus-bar electrode electrically connect was measured. Here, the connection region is a region where the distance between the solder and the bus bar electrode is approximately equal to or less than the particle size of the nickel particles. In Table 1, the width of the connection region with respect to the width of the wiring material in the second direction is shown as a relative value.

  From the results of Comparative Examples 1 and 2 and Examples 1 and 2, it was confirmed that the connection region can be increased by increasing the pressure-bonding pressure of the wiring material. Moreover, it was confirmed that the output fall of a solar cell can be suppressed, so that a connection area | region is enlarged. This is a result of reducing the contact resistance between the wiring member and the bus bar electrode by increasing the connection region.

  Similarly, from the results of Examples 3 to 6, it was confirmed that a decrease in the output of the solar cell can be suppressed by increasing the pressure-bonding pressure of the wiring member to increase the connection region.

  Moreover, when the results of Examples 1 and 2, Examples 3 to 6, and Comparative Examples 3 and 4 were compared, it was confirmed that when the particle size of the nickel particles was increased, the output decrease of the solar cell could be suppressed. This is because the connection region is a region in which the distance between the solder and the bus bar electrode is approximately equal to or smaller than the particle size of the nickel particles. The connection region is formed by nickel particles in the epoxy resin adhesive.

  When the results of Comparative Example 2 and Examples 7 and 8 were compared, it was confirmed that the connection region could be increased as the thickness difference between the central portion and the end portion of the solder was smaller. This is because the width of the connection region formed by the nickel particles can be increased as the wiring material is closer to a flat shape.

  On the other hand, from the result of Comparative Example 5, it was confirmed that when the wiring member is formed in a flat shape, the connection region is remarkably reduced. As a result, the output of the solar cell was significantly reduced by thermocompression bonding of the wiring material. This is because, since the wiring material is formed in a flat shape, the degassing of the epoxy resin adhesive cannot be promoted, and a gas lump remains as a cavity in the epoxy resin adhesive. That is, in Examples 1 to 8, deaeration of the epoxy resin adhesive is promoted.

It is a side view of the solar cell module 100 which concerns on 1st Embodiment of this invention. 1 is a plan view of a solar cell 10 according to a first embodiment of the present invention. It is sectional drawing in the AA cut surface of FIG. It is a figure which shows the state which joined the wiring material 11 to the bus-bar electrode 40 of FIG. It is sectional drawing in the BB cut surface of FIG. It is a figure for demonstrating the manufacturing method of the solar cell module 100 which concerns on 1st Embodiment of this invention. It is an expanded sectional view of the solar cell module 100 which concerns on 2nd Embodiment of this invention. It is a side view of the solar cell module 200 which concerns on 3rd Embodiment of this invention. It is a top view of the solar cell 10 which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which joined the wiring material 11 to the solar cell 10 which concerns on 3rd Embodiment of this invention. It is sectional drawing in the DD cut surface of FIG. It is sectional drawing in the EE cut surface of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solar cell string 2 ... Light-receiving surface side protective material 3 ... Back surface side protective material 4 ... Sealing material 10 ... Solar cell 11 ... Wiring material 11a ... Low resistance 11b ... Soft conductor 11c ... Soft conductor 12 ... Resin adhesion Agent 13 ... Particle 20 ... Photoelectric conversion part 20a ... ITO film 20b ... p-type amorphous silicon layer 20c ... i-type amorphous silicon layer 20d ... n-type single crystal silicon substrate 20e ... i-type amorphous silicon layer 20f ... n-type amorphous silicon layer 20g ... ITO film 30 ... fine wire electrode 40 ... bus bar electrode 40a ... projection 50 ... heater block 60 ... solar cell string 70 ... solar cell 72 ... resin adhesive 100 ... solar cell module 200 ... Solar cell module C ... Connection area F ... Connection area W1 ... Width W2 ... Width

Claims (11)

First and second solar cells arranged along a first direction;
A wiring member for connecting the first and second solar cell electrical manner,
A resin adhesive disposed between the wiring member and the main surface of the first solar cell;
With
The first solar cell is:
A photoelectric conversion unit that generates photogenerated carriers by receiving light; and
A collector electrode formed on the main surface of the photoelectric conversion unit and collecting the photogenerated carrier;
Have
The wiring member, in a cutting plane perpendicular to the first hand direction,
A convex portion in contact with the current collecting electrode;
A non-contact portion that is separated from the current collecting electrode and is bonded to the current collecting electrode through the resin adhesive,
A solar cell module. In the second direction perpendicular to the direction the first way, the width of the connection region for connecting the collector electrode and the wiring member electrically the solar greater claim 1, wherein than half the width of the wiring member Battery module. The resin adhesive does not include conductive particles,
The solar cell module according to claim 2, wherein the width of the connection region is a width in which the wiring member is in contact with the current collecting electrode.   The solar cell module according to claim 2 or 3, wherein a width of the resin adhesive in the second direction is larger than a width of the wiring member in the second direction. The current collecting electrode includes a plurality of fine wire electrodes for collecting the photogenerated carriers from the photoelectric conversion unit,
The solar cell module according to any one of claims 1 to 4 , wherein the connection region is formed by embedding a part of the thin wire electrode in the wiring member. The current collecting electrode includes a plurality of thin wire electrodes that collect the photogenerated carriers from the photoelectric conversion unit, and a bus bar electrode that collects the photo generated carriers from the thin wire electrodes,
The bus bar electrode is formed along the first direction,
The wiring member is disposed on the bus bar electrode,
The resin adhesive includes a plurality of conductive particles,
The solar cell module according to claim 1 , wherein the connection region is formed by the particles contained in the resin adhesive. First and second solar cells arranged along a first direction, a solar cell module comprising a wiring member for connecting the first and second solar cell electrical manner,
The first and second solar cells include a photoelectric conversion unit that generates photogenerated carriers by receiving light, and a plurality of thin wire electrodes that are formed on a main surface of the photoelectric conversion unit and collect the photogenerated carriers. A bus bar electrode formed along the first direction for collecting the photogenerated carriers from the thin wire electrode,
The wiring member is disposed on the bus bar electrode on the main surface of the first and second solar cells,
The bus bar electrode has a protrusion formed in a convex shape toward the wiring member,
The protrusion is formed at an end of the bus bar electrode in the second direction,
The protrusion is embedded in the wiring member;
Between the wiring material and the main surface of the first and second solar cells, a resin adhesive containing a plurality of conductive particles is disposed,
The cutting plane perpendicular to the first hand direction, the outer periphery of the wiring member is convexly formed toward the first and second solar cells,
In the second direction substantially orthogonal to the first direction, the width of the connection region that electrically connects the wiring member and the current collecting electrode is greater than half the width of the wiring member,
The connection region is a solar cell module formed by the particles contained in the resin adhesive. First and second solar cells arranged along a first direction, a manufacturing method of a solar cell module and a wiring member for connecting the first and second solar cells electrical manner,
Preparing the first and second solar cells by forming current collecting electrodes for collecting the photogenerated carriers on the main surface of the photoelectric conversion unit that generates photogenerated carriers by receiving light;
The cutting plane perpendicular to the direction the first way, the outer periphery of the wiring member is a convex portion is formed toward the first solar cell,
On the main surface of the first and second solar cells, the wiring material is thermocompression bonded below the melting point of the convex portion along the first direction via a resin adhesive,
In a second direction perpendicular to the first hand direction, it is brought into contact with the convex portion to the collector electrode,
The manufacturing method of the solar cell module which makes the said wiring material and the said collector electrode adhere | attach through the said resin adhesive agent while separating from the said collector electrode. The method for manufacturing a solar cell module according to claim 8, wherein a width of a connection region for electrically connecting the wiring member and the current collecting electrode is larger than half of a width of the wiring member. The resin adhesive is seen containing a plurality of particles having conductivity,
10. The solar cell module according to claim 9, wherein a width of the connection region is made larger than a half of a width of the wiring member by setting a particle size of the particles contained in the resin adhesive to be equal to or larger than a predetermined particle size. Manufacturing method. By making the pressure at the time of thermocompression bonding the wiring material on the main surfaces of the first and second solar cells to be equal to or higher than a predetermined pressure, the width of the connection region is larger than half of the width of the wiring material. The manufacturing method of the solar cell module of Claim 9.

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