JP6628196B2 - Solar cell module - Google Patents

Description

  The present invention relates to a solar cell module.

  Conventionally, solar cell modules have been developed as photoelectric conversion devices that convert light energy into electric energy. A solar cell module is expected as a new energy source because it can directly convert inexhaustible sunlight into electricity, and has a smaller environmental load and is cleaner than power generation using fossil fuels.

  The solar cell module has, for example, a structure in which a plurality of solar cell elements are sealed with a filling member between a front surface protection member and a back surface protection member. In a solar cell module, a plurality of solar cell elements are arranged in a matrix. A plurality of solar cell elements arranged linearly along one of the row direction and the column direction form a string in which two adjacent solar cell elements are connected by tab wiring.

  In Patent Literature 1, a solar cell in which a connection layer made of a resin containing a plurality of conductive particles is arranged between a tab wiring connecting two solar cell elements and a bus bar electrode formed on the surface of the solar cell element. Battery modules have been proposed.

JP 2008-135654 A

  However, in the conventional solar cell module, stress may occur in the tab wiring or the solar cell element between the solar cell elements due to expansion and contraction of the solar cell element and the tab wiring due to the temperature cycle.

  Then, this invention is made in order to solve the said subject, and an object of this invention is to provide the solar cell module which can reduce the stress of a tab wiring and a solar cell element.

  In order to solve the above problem, a solar cell module according to the present invention is arranged on two solar cell elements adjacent in a direction parallel to a light receiving surface, and on one surface and the other back surface of the two solar cell elements. A tab wire for electrically connecting the two solar cell elements; a plurality of finger electrodes formed on the front surface and the rear surface for collecting light-receiving charges generated by the solar cell elements; and the front surface and the rear surface. A bus bar electrode formed so as to extend in a direction intersecting each of the plurality of finger electrodes, and a bus bar electrode for electrically connecting the plurality of finger electrodes; An adhesive member for adhering the bus bar electrode and the tab wiring so as to be overlapped when viewed, and at least one of the front surface and the rear surface The film thickness of the intersecting portion which intersects with the finger electrodes of the bus bar electrode is thicker than the thickness of the sandwiched by intersection adjacent portions of the bus bar electrode.

  ADVANTAGE OF THE INVENTION According to the solar cell module which concerns on this invention, it becomes possible to reduce the stress of a tab wiring and a solar cell element.

FIG. 1 is a schematic plan view of the solar cell module according to Embodiment 1. FIG. 2 is a plan view of the solar cell element according to Embodiment 1. FIG. 3 is a cross-sectional view illustrating a stacked structure of the solar cell element according to Embodiment 1. FIG. 4 is a structural cross-sectional view of the solar cell module according to Embodiment 1 in the column direction. FIG. 5A is a structural cross-sectional view of the solar cell element according to Embodiment 1 in the column direction. FIG. 5B is a structural sectional view of a conventional solar cell element in a column direction. FIG. 5C is a diagram showing a modification of the structural cross section in the column direction of the solar cell element according to Embodiment 1. FIG. 6 is a plan view and a cross-sectional view illustrating an electrode configuration of the solar cell element according to Embodiment 1. FIG. 7 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification 1 of Embodiment 1. FIG. 8 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification 2 of Embodiment 1. FIG. 9A is a plan view and a cross-sectional view illustrating an electrode configuration of the solar cell element according to Embodiment 2. FIG. 9B is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification Example 1 of Embodiment 2. FIG. 9C is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification 2 of Embodiment 2. FIG. 10 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification 3 of Embodiment 2. FIG. 11A is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Embodiment 3. FIG. 11B is a diagram showing a step of forming electrodes of a solar cell element according to a modification of the third embodiment. FIG. 12 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to another embodiment. FIG. 13 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to another embodiment.

  Hereinafter, a solar cell module according to an embodiment of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement and connection forms of the constituent elements, and the like shown in the following embodiments are merely examples, and do not limit the present invention. Therefore, among the components in the following embodiments, components that are not described in independent claims that represent the highest concept of the present invention are described as arbitrary components.

  Each drawing is a schematic diagram, and is not necessarily illustrated exactly. In each of the drawings, the same components are denoted by the same reference numerals.

  In the present specification, the “front surface” of the solar cell element means a surface on which more light can enter the inside than the “back surface” which is the opposite surface (more than 50% to 100% of the light is on the front surface). From the inside), and also includes the case where no light enters the inside from the “back side” side. Further, the “front surface” of the solar cell module refers to a surface on which light on the side facing the “front surface” of the solar cell element can enter, and the “back surface” refers to a surface on the opposite side. Further, a description such as "providing a second member on a first member" is not intended only when the first and second members are provided in direct contact with each other, unless otherwise specified. That is, this description includes the case where another member exists between the first and second members. In addition, the description of “substantially **” is intended to include not only exactly the same but also substantially recognized as the same when describing “substantially the same” as an example.

(Embodiment 1)
[1-1. Basic configuration of solar cell module]
An example of the basic configuration of the solar cell module according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a schematic plan view of a solar cell module 1 according to Embodiment 1. FIG. The solar cell module 1 shown in FIG. 1 includes a plurality of solar cell elements 11, tab wires 20, crossover wires 30, and a frame 50.

  The solar cell element 11 is a flat photovoltaic cell which is two-dimensionally arranged on the light receiving surface and generates electric power by light irradiation.

  The tab wiring 20 is a wiring member arranged on the surface of the solar cell element 11 and electrically connecting the solar cell elements 11 adjacent in the column direction. Note that the tab wiring 20 may have a light diffusion shape on the light incident side surface. The light diffusion shape is a shape having a light diffusion function. With this light diffusion shape, light incident on the tab wiring 20 can be diffused on the surface of the tab wiring 20, and the diffused light can be redistributed to the solar cell element 11.

  The wiring 30 is a wiring member that connects the solar cell strings. The solar cell string is an aggregate of a plurality of solar cell elements 11 arranged in the column direction and connected by the tab wiring 20. A light diffusion shape may be formed on the light incident side surface of the crossover wiring 30. Thereby, the light incident between the solar cell element 11 and the frame body 50 is diffused across the surface of the wiring 30, and the diffused light can be redistributed to the solar cell element 11.

  The frame body 50 is an outer frame member that covers an outer peripheral portion of a panel in which the plurality of solar cell elements 11 are two-dimensionally arranged.

  Although not shown, a light diffusing member may be arranged between adjacent solar cell elements 11. Thereby, the light incident on the gap region between the solar cell elements 11 can be redistributed to the solar cell elements 11, so that the light collection efficiency of the solar cell elements 11 is improved. Therefore, it is possible to improve the photoelectric conversion efficiency of the entire solar cell module.

[1-2. Structure of solar cell element]
The structure of the solar cell element 11, which is a main component of the solar cell module 1, will be described.

  FIG. 2 is a plan view of the solar cell element 11 according to Embodiment 1. As shown in the figure, the solar cell element 11 has a substantially square shape in plan view. The solar cell element 11 is, for example, 125 mm long × 125 mm wide × 200 μm thick. A plurality of stripe-shaped bus bar electrodes 112 are formed on the surface of the solar cell element 11 in parallel with each other, and a plurality of stripe-shaped finger electrodes 111 are formed in parallel with each other so as to be orthogonal to the bus bar electrodes 112. I have. The bus bar electrode 112 and the finger electrode 111 constitute the collector electrode 110.

  For example, the collector electrode 110 can be formed by a printing method such as screen printing using a thermosetting resin-type conductive paste using a resin material as a binder and conductive particles such as silver particles as a filler. .

  The line width of the bus bar electrode 112 is, for example, 150 μm, the line width of the finger electrode 111 is, for example, 100 μm, and the pitch of the finger electrodes 111 is, for example, 2 mm. The tab wiring 20 is joined on the bus bar electrode 112.

  FIG. 3 is a cross-sectional view illustrating a stacked structure of solar cell element 11 according to Embodiment 1. FIG. 3 is a sectional view of the solar cell element 11 taken along the line III-III in FIG. As shown in FIG. 3, an i-type amorphous silicon film 121 and a p-type amorphous silicon film 122 are formed in this order on a main surface of an n-type single crystal silicon wafer 101. The n-type single-crystal silicon wafer 101, the i-type amorphous silicon film 121, and the p-type amorphous silicon film 122 form a photoelectric conversion layer, and the n-type single-crystal silicon wafer 101 becomes a main power generation layer. Further, the light receiving surface electrode 102 is formed on the p-type amorphous silicon film 122. As shown in FIG. 2, on the light receiving surface electrode 102, a collecting electrode 110 including a plurality of bus bar electrodes 112 and a plurality of finger electrodes 111 is formed. FIG. 3 shows only the finger electrodes 111 among the collecting electrodes 110.

  On the back surface of the n-type single crystal silicon wafer 101, an i-type amorphous silicon film 123 and an n-type amorphous silicon film 124 are formed in this order. Further, a light receiving surface electrode 103 is formed on the n-type amorphous silicon film 124, and a collecting electrode 110 including a plurality of bus bar electrodes 112 and a plurality of finger electrodes 111 is formed on the light receiving surface electrode 103.

  Note that even if the p-type amorphous silicon film 122 is formed on the back surface side of the n-type single crystal silicon wafer 101 and the n-type amorphous silicon film 124 is formed on the light receiving surface side of the n-type single crystal silicon wafer 101, respectively. Good.

  Note that, as shown in FIG. 3, the pitch of the finger electrodes 111 on the back surface may be smaller than the pitch of the finger electrodes on the front surface. In other words, the number of finger electrodes 111 on the back surface may be larger than the number of finger electrodes on the front surface. That is, the area occupancy of the collector electrode formed on the back surface may be higher than the area occupancy of the collector electrode formed on the front surface. Here, the area occupancy of the collector electrode is a ratio of the total area of the bus bar electrodes 112 and the finger electrodes 111 in plan view to the area of the solar cell element 11 in plan view.

  In the case of the above-described electrode arrangement on the back surface, the current collection efficiency on the back surface increases, but the light shielding loss increases as compared with the front surface. However, since the solar cell element 11 according to the present embodiment is a single-sided light-receiving type in which the light-receiving surface is the front surface, the effect of the increase in current collection efficiency on the back surface is more significant than the effect of the increase in light-blocking loss on the back surface. large. Therefore, the current collection effect of the solar cell element 11 can be improved.

  The solar cell element 11 according to the present embodiment has a structure in which the n-type single-crystal silicon wafer 101 and the p-type amorphous silicon film 122 or the n-type amorphous silicon film 124 are provided to improve pn junction characteristics. , An i-type amorphous silicon film 121 is provided.

  Solar cell element 11 according to the present embodiment is a single-sided light-receiving type, and light-receiving surface electrode 102 on the front side of n-type single-crystal silicon wafer 101 serves as a light-receiving surface. Carriers generated in the n-type single-crystal silicon wafer 101 are diffused as photocurrents into the light-receiving surface electrodes 102 and 103 on the front surface side and the rear surface side, and are collected by the collecting electrode 110.

The light receiving surface electrodes 102 and 103 are transparent electrodes made of, for example, ITO (indium tin oxide), SnO ₂ (tin oxide), ZnO (zinc oxide), or the like. The light-receiving surface electrode 103 on the back side may be a non-transparent metal electrode. In addition, an electrode formed on the entire surface of the light receiving surface electrode 103 may be used instead of the collector electrode 110 as the back electrode.

  Note that the solar cell element according to the present embodiment may be of a double-sided light receiving type. In this case, the light receiving surface electrode 102 on the front side and the light receiving surface electrode 103 on the back side of the n-type single crystal silicon wafer 101 are light receiving surfaces. Carriers generated in the n-type single-crystal silicon wafer 101 are diffused as photocurrents into the light receiving surface electrodes 102 and 103 on the front surface side and the rear surface side, and are collected by the collecting electrode 110. The light receiving surface electrodes 102 and 103 are transparent electrodes.

[1-3. Structure of solar cell module]
Next, a specific structure of solar cell module 1 according to the present embodiment will be described.

  FIG. 4 is a structural cross-sectional view of the solar cell module 1 according to Embodiment 1 in the column direction. Specifically, FIG. 4 is a cross-sectional view taken along line IV-IV of the solar cell module 1 of FIG. The solar cell module 1 shown in FIG. 1 includes a solar cell element 11 having a collector electrode 110 formed on the front and back surfaces, a tab wiring 20, an adhesive member 40, a surface filling member 70A and a back surface filling member 70B, The front surface protection member 80 and the back surface protection member 90 are provided.

  The tab wiring 20 is a long conductive wiring, for example, a ribbon-shaped metal foil. The tab wiring 20 can be produced, for example, by cutting a metal foil, such as a copper foil or a silver foil, whose entire surface is covered with silver, solder, or the like, into a strip having a predetermined length. In two solar cell elements 11 adjacent in the column direction, the tab wiring 20 arranged on the front surface of one solar cell element 11 is also arranged on the back surface of the other solar cell element 11. More specifically, the lower surface of one end of the tab wiring 20 is joined to the bus bar electrode 112 (see FIG. 2) on the front surface side of one of the solar cell elements 11 along the longitudinal direction of the bus bar electrode 112. The upper surface of the other end of the tab wiring 20 is joined to the bus bar electrode on the back surface side of the other solar cell element 11 along the longitudinal direction of the bus bar electrode 112. Thereby, the solar cell string including the plurality of solar cell elements 11 arranged in the column direction has a configuration in which the plurality of solar cell elements 11 are connected in series in the column direction.

  The tab wiring 20 and the bus bar electrode 112 (see FIG. 2) are joined by the adhesive member 40. That is, the bonding member 40 bonds the bus bar electrode 112 and the tab wiring 20 such that the bus bar electrode 112 and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Thereby, the tab wiring 20 is connected to the solar cell element 11 via the adhesive member.

  As the adhesive member 40, for example, a conductive adhesive paste, a conductive adhesive film, an anisotropic conductive film, a conductive adhesive tape, or the like can be used. The conductive adhesive paste is, for example, a paste adhesive in which conductive particles are dispersed in a thermosetting adhesive resin material such as an epoxy resin, an acrylic resin, or a urethane resin. The conductive adhesive film and the anisotropic conductive film are formed into a film by dispersing conductive particles in a thermosetting adhesive resin material. Further, as the bonding member 40, a non-conductive bonding agent can be used. In this case, by appropriately designing the application thickness of the resin adhesive, the resin adhesive is softened at the time of pressurization during thermocompression bonding, and the surface of the bus bar electrode 112 and the tab wiring 20 are brought into direct contact with each other to provide electrical connection. Can be connected.

  According to this configuration, the plurality of finger electrodes 111 collect light-receiving charges generated by the solar cell element 11, and the bus bar electrodes 112 are formed so as to extend in a direction crossing each of the plurality of finger electrodes 111. The received charges are transmitted to the tab wiring 20.

  Further, as shown in FIG. 4, a front surface protection member 80 is provided on the front surface side of the plurality of solar cell elements 11, and a rear surface protection member 90 is provided on the back surface side. A surface filling member 70A is disposed between the surface including the plurality of solar cell elements 11 and the surface protection member 80, and a back surface filling member is provided between the surface including the plurality of solar cell elements 11 and the back surface protection member 90. The member 70B is arranged. The front surface protection member 80 and the back surface protection member 90 are fixed by a front surface filling member 70A and a back surface filling member 70B, respectively.

  The surface protection member 80 is a protection member arranged on the surface side of the solar cell element 11. The surface protection member 80 is a member for protecting the inside of the solar cell module 1 from wind and rain, external impact, fire, and the like, and ensuring long-term reliability of the solar cell module 1 in outdoor exposure. From this viewpoint, the surface protection member 80 can be made of, for example, a glass having a light-transmitting property and a water-blocking property, or a resin material having a film-like or plate-like hard light-transmitting and water-blocking property.

  The back surface protection member 90 is a protection member arranged on the back surface side of the solar cell element 11. The back surface protection member 90 is a member that protects the back surface of the solar cell module 1 from the external environment. For example, a resin film such as polyethylene terephthalate or a laminated film having a structure in which an Al foil is sandwiched between resin films is used. Can be.

  The surface filling member 70A is a filler filled in a space between the plurality of solar cell elements 11 and the surface protection member 80, and the back surface filling member 70B is formed of the plurality of solar cell elements 11 and the back surface protection member 90. It is a filler filled in the space between them. The front surface filling member 70A and the back surface filling member 70B have a sealing function for shielding the solar cell element 11 from the external environment. By arranging the surface filling member 70A and the back surface filling member 70B, it is possible to ensure high heat resistance and high moisture resistance of the solar cell module 1 which is assumed to be installed outdoors.

  The surface filling member 70A is made of a translucent polymer material having a sealing function. As the polymer material of the surface filling member 70A, for example, a translucent resin material such as ethylene vinyl acetate (EVA) is used.

  The back surface filling member 70B is made of a polymer material having a sealing function. Here, the back surface filling member 70B is, for example, white processed. As the polymer material of the back surface filling member 70B, for example, a resin material obtained by subjecting EVA or the like to white processing is used.

  In addition, it is preferable that the surface filling member 70A and the back surface filling member 70B are the same material system from the viewpoint of simplification of the manufacturing process and the adhesion of the interface between the surface filling member 70A and the back surface filling member 70B. The front filling member 70A and the back filling member 70B are formed by laminating two resin sheets (a translucent EVA sheet and a white EVA sheet) sandwiching a plurality of solar cell elements 11 (cell strings) (lamination processing). It is formed by doing.

[1-4. Adhesion structure between tab wiring and solar cell element]
FIG. 5A is a structural cross-sectional view of the solar cell element 11 according to Embodiment 1 in the column direction. More specifically, FIG. 5A is a cross-sectional view in which the vicinity of the surface of solar cell element 11 in the structural cross-sectional view of FIG. 4 is enlarged. As shown in the figure, the bus bar electrode 112 and the tab wiring 20 are bonded by the bonding member 40.

  FIG. 5B is a structural sectional view of a conventional solar cell element in a column direction. As shown in FIG. 5B, in the conventional solar cell module, the solar cell element 11 and the tab wiring 20 are uniformly bonded by the adhesive member 540 over the entire area of the solar cell element 11 in the longitudinal direction of the tab wiring 20. ing. For this reason, when the solar cell element 11 and the tab wiring 20 repeat expansion and contraction due to the temperature cycle, stress may occur in the tab wiring 20 or the solar cell between the solar cells.

  On the other hand, in the solar cell module 1 according to the present embodiment, the thickness of the bus bar electrode 112 at the intersection Px where the bus bar electrode 112 and the finger electrode 111 intersect is such that the bus bar sandwiched between the adjacent intersections Px It is characterized in that it is thicker than the film thickness of the non-intersecting portion Py of the electrode 112. According to this configuration, the bus bar electrode 112 and the tab wiring 20 are closest to each other at the intersection Px and are in an electrically conductive state, and at the non-intersection Py, the bus bar electrode 112 and the tab wiring 20 are connected via the adhesive member 40. Separate. That is, the bus bar electrode 112 and the tab wiring 20 are intermittently contacted or closest to the bus bar electrode 112 in the longitudinal direction. In other words, the amount (thickness) of the resin material (adhesive member 40) interposed between the bus bar electrode 112 and the tab wiring 20 in the non-intersecting portion Py depends on the distance between the bus bar electrode 112 and the tab wiring 20 in the intersecting portion Px. Is larger (thicker) than the amount (thickness) of the adhesive member 40 interposed in the second member. For this reason, even if the solar cell element 11 and the tab wiring 20 repeat thermal expansion and thermal contraction, the stress generated in the long direction due to the difference in the thermal expansion coefficient between the solar cell element 11 and the tab wiring 20 does not intersect. It can be alleviated by the portion Py. Therefore, stress on the tab wiring 20 between the solar cell elements and the solar cell elements can be reduced.

  If the bus bar electrode 112 and the tab wiring 20 are electrically connected at the intersection Px, the received charge generated in the solar cell element 11 and collected by the finger electrode 111 is transmitted to the tab wiring 20. Is possible. Therefore, at the non-intersecting portion Py, the bus bar electrode 112 and the tab wiring 20 need not be bonded via the bonding member 40.

  FIG. 5C is a diagram showing a modification of the structural cross section in the column direction of the solar cell element according to Embodiment 1. As shown in the figure, for example, when the adhesive member 40 is a non-conductive adhesive made of resin, the surface of the bus bar electrode 112 and the tab wiring 20 are brought into direct contact at the intersection Px. What is necessary is just to electrically connect. As a result, the bus bar electrode 112 and the tab wiring 20 are intermittently contacted in the longitudinal direction of the tab wiring 20, and the solar cell element 11 and the tab wiring 20 are secured while maintaining electrical connection at the intersection Px. The stress generated in the longitudinal direction due to the difference in the coefficient of thermal expansion with the non-intersecting portion Py can be reduced.

  In addition, between the bus bar electrode 112 and the tab wiring 20 at the non-intersecting portion Py, the surface filling member 70A or the back surface filling member 70B may be interposed instead of the adhesive member 40 interposed.

[1-5. Connection configuration between collector electrode and tab wiring according to the first embodiment]
FIG. 6 is a plan view and a cross-sectional view illustrating an electrode configuration of solar cell element 11A according to Embodiment 1. More specifically, FIG. 6 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

  As shown in the perspective plan view of FIG. 6, a bus bar electrode 112A and a plurality of finger electrodes 111A orthogonal to and parallel to the bus bar electrode 112A are arranged on the surface of the solar cell element 11A. The bonding member 40 for bonding the bus bar electrode 112A and the tab wiring 20 is arranged such that the bus bar electrode 112A and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 6, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11A. Is formed in a region facing the finger electrode 111A and the bus bar electrode 112A on the lower surface of the substrate.

  Here, the electrode width W1s of the finger electrode 111A at the intersection Px between the bus bar electrode 112A and the finger electrode 111A is wider than the electrode width W1n of the non-intersection portion Pz, which is another part of the finger electrode 111A.

  As described above, for example, the finger electrode 111A and the bus bar electrode 112A are screen-printed using a thermosetting resin-type conductive paste using a resin material as a binder and conductive particles such as silver particles as a filler. Is formed by the printing method described above. In this case, the finger electrodes 111A and the bus bar electrodes 112A are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass through in a mesh pattern. For this reason, if the line width of the screen mask is relatively widened, the line width of the printed electrode can be relatively widened and the film thickness can be relatively thick. Here, as a method of controlling the thickness of the electrode, for example, by adjusting the mesh of the screen plate used during screen printing, and the specifications of the emulsion, to narrow or widen the opening of the emulsion And reducing or increasing the amount of paste discharged. This makes it possible to positively execute the control of reducing or increasing the film thickness of the electrode.

  Due to the difference in electrode width (W1s> W1n) between the intersecting portion Px and the non-intersecting portion Pz of the finger electrode 111A and the correlation between the electrode width and the film thickness by screen printing, the film thickness at the intersecting portion Px of the finger electrode 111A is Is thicker than the film thickness at the non-intersecting portion Pz of the finger electrode 111A.

  Therefore, as shown in the cross-sectional view of FIG. 6, the intersection Px of the bus bar electrode 112A is thicker than the non-intersection Py of the bus bar electrode 112A.

  As described above, the tape-shaped or sheet-shaped resin material serving as the adhesive member 40 is softened by being thermocompression-bonded between the bus bar electrode 112A and the tab wiring 20, for example. Thereby, the tab wiring 20 and the bus bar electrode 112A are joined.

  According to the thickness distribution in the longitudinal direction of the bus bar electrode 112A and the bonding method using the resin material, the bus bar electrode 112A and the tab wiring 20 are in contact with or closest to each other at the intersection Px, and The bus bar electrode 112A and the tab wiring 20 are separated via the resin material.

  According to the above connection configuration, even when the solar cell element 11A and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11A and the tab wiring 20 are maintained while maintaining electrical continuity between the bus bar electrode 112A and the tab wiring 20. The stress generated in the longitudinal direction can be reduced due to the difference in the coefficient of thermal expansion from the coefficient of thermal expansion. Therefore, as compared with the case where the bus bar electrode 112A and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11A between the solar cell elements 11A is reduced. Can be reduced.

  In FIG. 6, an electrode group that extends in a direction parallel to the finger electrode 111A, intersects with the bus bar electrode 112A, and is shorter than the finger electrode 111A may be arranged between the adjacent finger electrodes 111A. Although this electrode group is for reinforcing the adhesion between the tab wiring 20 and the solar cell element 11A, the electrode group may be regarded as a finger electrode 111A. That is, the thickness of the bus bar electrode 112 at the intersection where the bus bar electrode 112 intersects with the electrode group may be greater than the thickness of the non-intersecting portion of the bus bar electrode 112 sandwiched between adjacent intersections. Thereby, the stress generated in the longitudinal direction due to the difference in the thermal expansion coefficient between the solar cell element 11 and the tab wiring 20 can be reduced by the non-intersecting portion, while ensuring electrical connection at the intersecting portion. Further, in the following embodiments and modifications thereof, similarly, an electrode group arranged between a plurality of finger electrodes can be regarded as a finger electrode, and the same effect can be obtained. .

  In FIG. 6, the length in the extending direction of the finger electrode 111 </ b> A at the intersection Px may be larger or smaller than the width of the tab wiring 20. However, the length of the intersection Px in the extending direction is smaller than the width of the tab wiring 20 (the intersection Px covers the tab wiring 20 so that the intersection Px does not block light incident on the solar cell element 11A). Preferably).

[1-6. Connection configuration between collector electrode and tab wiring according to Modification 1 of Embodiment 1]
FIG. 7 is a plan view and a cross-sectional view illustrating an electrode configuration of solar cell element 11B according to Modification Example 1 of Embodiment 1. More specifically, FIG. 7 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11B according to this modification is different from the electrode configuration of the solar cell element 11A shown in FIG. 6 only in the configuration of the bus bar electrode 112B. In the following, description of the same points as those of the electrode configuration of solar cell element 11A shown in FIG. 6 will be omitted, and different points will be mainly described.

  As shown in the perspective plan view of FIG. 7, a bus bar electrode 112B and a plurality of finger electrodes 111B crossing the bus bar electrode 112B and being parallel to each other are arranged on the surface of the solar cell element 11B. The bonding member 40 that bonds the bus bar electrode 112B and the tab wiring 20 is arranged so that the bus bar electrode 112B and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 7, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11B. Is formed in a region facing the finger electrode 111B and the bus bar electrode 112B on the lower surface of the substrate.

  The bus bar electrode 112B does not have a linear shape parallel to the elongate direction where the tab wiring 20 is arranged, but has a component that extends in an oblique direction with respect to the elongate direction. Has a zigzag shape that converts

  Here, the electrode width W1s of the finger electrode 111B at the intersection Px between the bus bar electrode 112B and the finger electrode 111B is wider than the electrode width W1n of the non-intersection part Pz, which is another part of the finger electrode 111B.

  Due to the difference in electrode width between the intersecting portion Px and the non-intersecting portion Pz of the finger electrode 111B and the correlation between the electrode width and the film thickness by screen printing, the film thickness at the intersecting portion Px of the finger electrode 111B becomes smaller than the finger electrode 111B. Is thicker than the film thickness at the non-intersecting portion Pz.

  Therefore, as shown in the cross-sectional view of FIG. 7, the intersection Px of the bus bar electrode 112B is thicker than the non-intersection Py of the bus bar electrode 112B.

  According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112B, at the intersection Px, the bus bar electrode 112B and the tab wiring 20 are in contact with or closest to each other, and at the non-crossing part Py, the bus bar electrode 112B and the tab wiring 20 , And are separated by the resin material.

  According to the above connection configuration, even when the solar cell element 11B and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical connection between the bus bar electrode 112B and the tab wiring 20 is maintained, and the solar cell element 11B and the tab wiring 20 are maintained. The stress generated in the longitudinal direction can be reduced due to the difference in the coefficient of thermal expansion from the coefficient of thermal expansion. Therefore, the stress of the tab wiring 20 between the solar cell elements 11B and the solar cell element 11B can be reduced.

[1-7. Connection configuration between collector electrode and tab wiring according to Modification 2 of Embodiment 1]
FIG. 8 is a plan view and a cross-sectional view illustrating an electrode configuration of solar cell element 11C according to Modification 2 of Embodiment 1. More specifically, FIG. 8 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11C according to the present modification specifies a region where a characteristic electrode configuration is formed as a cell end region, as compared with the electrode configuration of the solar cell element 11A shown in FIG. Only the difference. In the following, description of the same points as those of the electrode configuration of solar cell element 11A shown in FIG. 6 will be omitted, and different points will be mainly described.

  As shown in the perspective plan view of FIG. 8, a bus bar electrode 112C and a plurality of finger electrodes 111CC and 111CP orthogonal to the bus bar electrode 112C and parallel to each other are arranged on the surface of the solar cell element 11C. Further, the bonding member 40 for bonding the bus bar electrode 112C and the tab wiring 20 is arranged so that the bus bar electrode 112C and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 8, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11C. Are formed in a region facing the finger electrodes 111CC, 1111CP and the bus bar electrode 112A on the lower surface of the substrate.

  Finger electrode 111CC is formed in central region Ac of solar cell element 11C, and finger electrode 111CP is formed in end area Ap of solar cell element 11C.

  Here, the electrode width W1ps of the finger electrode 111CP at the intersection Px between the bus bar electrode 112C and the finger electrode 111CP is wider than the electrode width W1pn of the non-intersection portion Pz, which is another part of the finger electrode 111CP.

  Due to the difference in electrode width between the intersecting portion Px and the non-intersecting portion Pz of the finger electrode 111CP and the correlation between the electrode width and the film thickness by screen printing, the film at the intersecting portion Px of the finger electrode 111CP in the end region Ap. The thickness is larger than the film thickness at the non-intersecting portion Pz of the finger electrode 111CP.

  Accordingly, as shown in the cross-sectional view of FIG. 8, the intersection Px of the bus bar electrode 112C in the end region Ap is thicker than the non-intersection Py of the bus bar electrode 112C.

  According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112C, at the intersection Px in the end region Ap, the bus bar electrode 112C is in contact with or closest to the tab wiring 20, and at the non-intersection Py in the end region Ap. The bus bar electrode 112C and the tab wiring 20 are separated from each other via the resin material.

  According to the above connection configuration, even when the solar cell element 11B and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical connection between the bus bar electrode 112B and the tab wiring 20 is maintained, and the solar cell element 11B and the tab wiring 20 are maintained. The stress generated in the longitudinal direction due to the difference in the coefficient of thermal expansion from 20 can be reduced in the end region Ap of the solar cell element 11C. Therefore, the stress of the tab wiring 20 between the solar cell elements 11C and the solar cell element 11C can be reduced more effectively, particularly in the end region Ap where the tab wiring 20 is easily subjected to stress.

(Embodiment 2)
In the solar cell module according to the present embodiment, as in solar cell module 1 according to Embodiment 1, the intersection Px that intersects the finger electrode of the bus bar electrode is thicker than the non-intersection portion Py of the bus bar electrode. And In order to realize this, in the first embodiment, the electrode width W1s of the finger electrode 111A at the intersection Px is wider than the electrode width W1n of the non-intersection Pz of the finger electrode 111A. On the other hand, in the present embodiment, the electrode width of the bus bar electrode is smaller than the electrode width of the finger electrode.

  The basic configuration and the like of the solar cell module according to the present embodiment are the same as those according to the first embodiment, and thus description thereof is omitted. Hereinafter, the electrode configuration and cross-sectional structure of solar cell element 11D different from the first embodiment This will be mainly described.

[2-1. Connection configuration between collector electrode and tab wiring according to Embodiment 2]
FIG. 9A is a plan view and a cross-sectional view illustrating an electrode configuration of solar cell element 11D according to Embodiment 2. More specifically, FIG. 9A is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

  As shown in the perspective plan view of FIG. 9A, a bus bar electrode 112D and a plurality of finger electrodes 111D that are orthogonal to and parallel to the bus bar electrode 112D are arranged on the surface of the solar cell element 11D. Further, the bonding member 40 for bonding the bus bar electrode 112D and the tab wiring 20 is arranged so that the bus bar electrode 112D and the tab wiring 20 overlap when the light receiving surface is viewed in a plan view. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 9A, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11D. Is formed in a region facing the finger electrode 111D and the bus bar electrode 112D on the lower surface of the substrate.

  Here, the electrode width W2n of the bus bar electrode 112D is smaller than the electrode width W1n of the finger electrode 111D.

  The finger electrodes 111D and the bus bar electrodes 112D can be formed by, for example, a printing method such as screen printing. In this case, the finger electrodes 111D and the busbar electrodes 112D are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass therethrough in a mesh pattern. For this reason, when the line width of the screen mask is relatively widened, the line width of the printed electrode is relatively wide, and the film thickness is relatively thick.

  Due to the difference in electrode width between the bus bar electrode 112D and the finger electrode 111D, and the correlation between the electrode width and the film thickness by screen printing, the thickness of the finger electrode 111D is larger than the thickness of the bus bar electrode 112D.

  Therefore, as shown in the cross-sectional view of FIG. 9A, the intersection Px of the bus bar electrode 112D is thicker than the non-intersection Py of the bus bar electrode 112D.

  As described above, the tape-shaped or sheet-shaped resin material as the adhesive member 40 is softened by being thermocompression-bonded between the bus bar electrode 112D and the tab wiring 20, for example. Thereby, the tab wiring 20 and the bus bar electrode 112D are joined.

  According to the thickness distribution in the longitudinal direction of the bus bar electrode 112D and the bonding method using the resin material, the bus bar electrode 112D and the tab wiring 20 are in contact with or closest to the intersection Px, and The bus bar electrode 112D and the tab wiring 20 are separated via the resin material.

  According to the above-described connection configuration, even when the solar cell element 11D and the tab wiring 20 repeat thermal expansion and thermal contraction, the solar cell element 11D and the tab wiring 20 are maintained while maintaining electrical continuity between the bus bar electrode 112D and the tab wiring 20. The stress generated in the longitudinal direction can be reduced due to the difference in the coefficient of thermal expansion from the coefficient of thermal expansion. Therefore, compared to the case where the bus bar electrode 112D and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the longitudinal direction, the stress of the tab wiring 20 and the solar cell element 11D between the solar cell elements 11D is reduced. Can be reduced.

[2-2. Connection configuration between collector electrode and tab wiring according to Modification 1 of Embodiment 2]
FIG. 9B is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification Example 1 of Embodiment 2. More specifically, FIG. 9B is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11H according to this modification is different from the electrode configuration of the solar cell element 11D shown in FIG. 9A in that the characteristic electrode configuration is different between the cell end region and the cell central region. Is different. In the following, the same points as those of the electrode configuration of solar cell element 11D shown in FIG. 9A will not be described, and different points will be mainly described.

  As shown in the perspective plan view of FIG. 9B, a bus bar electrode 112H and a plurality of finger electrodes 111HC and 111HP that are orthogonal to and parallel to the bus bar electrode 112H are arranged on the surface of the solar cell element 11H. The bonding member 40 that bonds the bus bar electrode 112H and the tab wiring 20 is arranged so that the bus bar electrode 112H and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the bonding member 40 is not shown in the perspective plan view of FIG. 9B, the bonding member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11H. Is formed in a region facing the finger electrodes 111HC, 1111HP and the bus bar electrode 112H on the lower surface of the.

  Finger electrode 111HC is formed in central region Ac of solar cell element 11H, and finger electrode 111HP is formed in end area Ap of solar cell element 11H.

  Here, the electrode width W1np of the finger electrode 111HP is wider than the electrode width W1nc of the finger electrode 111HC.

  Due to the difference between the electrode widths of the finger electrodes 111HP and 111HC, and the correlation between the electrode width and the film thickness by screen printing, the electrode film thickness at the intersection Pxp between the finger electrode 111HP and the bus bar electrode 112H in the end region Ap is: The electrode thickness at the intersection Pxc between the finger electrode 111HC and the bus bar electrode 112H in the central region Ac is larger than the electrode thickness.

  When the tab wiring 20 is bonded to the bus bar electrode 112H having the above-described relationship of the electrode thickness, a cross-sectional structure as shown in a cross-sectional view of FIG. 9B is obtained. That is, the distance between the tab wiring 20 and the bus bar electrode 112H at the non-intersecting portion Pyp between the finger electrode 111HP and the bus bar electrode 112H in the end region Ap is the non-intersecting portion Pyc between the finger electrode 111HC and the bus bar electrode 112H in the central region Ac. Is larger than the distance between the tab wiring 20 and the bus bar electrode 112H.

  9B shows a cross-sectional view of the non-intersecting portions Pyp and Pyc cut in the extending direction of the finger electrodes. Here, (1) the distance between the tab wiring 20 and the bus bar electrode 112H at the non-intersecting portion Pyp is larger than the distance between the tab wiring 20 and the bus bar electrode 112H at the non-intersecting portion Pyc, and (2) the non-intersecting portion Since the cross-sectional area Sp of the adhesive member 40 at the non-intersecting portion Pyc is equal to the cross-sectional area Sp of the adhesive member 40 at the non-intersecting portion Pyc, the bonding width of the tab wiring 20 and the adhesive member 40 at the non-intersecting portion Pyp in the above-described extending direction. Wp40 is smaller than the bonding width Wc40 between the tab wiring 20 and the bonding member 40 in the extending direction in the non-intersecting portion Pyc.

  Therefore, the adhesive strength between the tab wiring 20 and the bus bar electrode 112H at the non-intersecting portion Pyp in the end region Ap is lower than the adhesive strength between the tab wiring 20 and the bus bar electrode 112H at the non-intersecting portion Pyc in the end region Ac. .

  According to the above-described bonding structure between the tab wiring 20 and the bus bar electrode 112H, the bus bar electrode 112H and the tab wiring 20 are in contact with or closest to the intersection Pxp and Pxc, and the bus bar electrode 112H and the tab are non-crossing parts Pyp and Pyc. It is separated from the wiring 20 via the resin material. Further, the non-intersecting portion Pyp has a lower adhesive strength than the non-intersecting portion Pyc.

  According to the above connection configuration, even if the solar cell element 11H and the tab wiring 20 repeatedly undergo thermal expansion and thermal contraction, electrical connection between the bus bar electrode 112H and the tab wiring 20 is maintained, while the solar cell element 11H and the tab wiring 20 are maintained. The stress generated in the longitudinal direction due to the difference in the coefficient of thermal expansion from 20 can be reduced in the end region Ap of the solar cell element 11H. Therefore, especially in the end region Ap where the tab wiring 20 is easily subjected to stress, the stress of the tab wiring 20 between the solar cell elements 11H and the stress of the solar cell element 11H can be more effectively reduced.

[2-3. Connection configuration between collector electrode and tab wiring according to Modification 2 of Embodiment 2]
FIG. 9C is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element according to Modification 2 of Embodiment 2. More specifically, FIG. 9C is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11J according to this modification is different from the electrode configuration of the solar cell element 11D shown in FIG. 9A in that the characteristic electrode configuration is different between the cell end region and the cell central region. Is different. Hereinafter, the same points as those of the electrode configuration of solar cell element 11D shown in FIG. 9A will not be described, and different points will be mainly described.

  As shown in the perspective plan view of FIG. 9C, on the surface of solar cell element 11J, bus bar electrodes 112JC and 112JP, and a plurality of finger electrodes 111J orthogonal to bus bar electrodes 112JC or 112JP and parallel to each other are arranged. Further, an adhesive member 40 for bonding the bus bar electrodes 112JC and 112JP and the tab wiring 20 is arranged such that the bus bar electrodes 112JP and 112JP and the tab wiring 20 overlap when the light receiving surface is viewed in plan. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 9C, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11J. Is formed in a region facing the finger electrode 111J and the bus bar electrodes 112JC and 112JP on the lower surface of the.

  The bus bar electrode 112JC is formed in the central region Ac of the solar cell element 11J, and the bus bar electrode 112JP is formed in the end region Ap of the solar cell element 11J.

  Here, the electrode width W2np of the bus bar electrode 112JP is smaller than the electrode width W2nc of the bus bar electrode 112JP.

  Due to the difference between the electrode widths of the bus bar electrodes 112JC and 112JP, and the correlation between the electrode width and the film thickness by screen printing, the electrode film thickness at the intersection Pxp between the finger electrode 111J and the bus bar electrode 112JP in the end region Ap is: The electrode thickness at the intersection Pxc between the finger electrode 111J and the bus bar electrode 112JC in the central region Ac is thinner. The electrode film thickness at the non-intersecting portion Pyp between the finger electrode 111J and the bus bar electrode 112JP in the end region Ap is smaller than the electrode film thickness at the non-intersecting portion Pyc between the finger electrode 111J and the bus bar electrode 112JC in the central region Ac. Become.

  When the tab wiring 20 is bonded to the bus bar electrodes 112JC and 112JP having the above-described relationship of the electrode film thickness, a cross-sectional structure as shown in a cross-sectional view of FIG. 9C is obtained.

  9C shows a cross-sectional view of the non-intersecting portions Pyp and Pyc cut in the extending direction of the finger electrodes. Here, (1) the cross-sectional area of the bus bar electrode 112JP at the non-intersecting portion Pyp is smaller than the cross-sectional area of the bus bar electrode 112JP at the non-intersecting portion Pyc, and (2) the cross-sectional area of the bonding member 40 at the non-intersecting portion Pyp. Since Sp and the cross-sectional area Sc of the adhesive member 40 at the non-intersecting portion Pyc are equal, the adhesive width Wp40 of the tab wiring 20 and the adhesive member 40 in the extending direction at the non-intersecting portion Pyc is equal to that at the non-intersecting portion Pyc. The width is smaller than the bonding width Wc40 between the tab wiring 20 and the bonding member 40 in the extending direction.

  Therefore, the adhesive strength between the tab wiring 20 and the bus bar electrode 112JP at the non-intersecting portion Pyp of the end region Ap is lower than the adhesive strength between the tab wiring 20 and the bus bar electrode 112JC at the non-intersecting portion Pyc of the end region Ac. .

  According to the above-described bonding structure between the tab wiring 20 and the bus bar electrodes 112JC and 112JP, the bus bar electrodes 112JP and 112JC and the tab wiring 20 are in contact with or closest to each other at the intersection portions Pxp and Pxc, and the bus bar is formed at the non-intersecting portions Pyp and Pyc. The electrodes 112JP and 112JC are separated from the tab wiring 20 via the resin material. Further, the non-intersecting portion Pyp has a lower adhesive strength than the non-intersecting portion Pyc.

  According to the above connection configuration, even when the solar cell element 11J and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical connection between the bus bar electrodes 112JC and 112JP and the tab wiring 20 is maintained, and the solar cell element 11J and the tab wiring 20 are connected to each other. The stress generated in the longitudinal direction due to the difference in the thermal expansion coefficient from the tab wiring 20 can be reduced in the end region Ap of the solar cell element 11J. Therefore, especially in the end region Ap where the tab wiring 20 is easily stressed, the stress of the tab wiring 20 between the solar cell elements 11J and the stress of the solar cell element 11J can be reduced more effectively.

[2-4. Connection configuration between collector electrode and tab wiring according to Modification 3 of Embodiment 2]
FIG. 10 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element 11E according to a third modification of the second embodiment. More specifically, FIG. 10 is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged. The electrode configuration of the solar cell element 11E according to this modification is different from the electrode configuration of the solar cell element 11D shown in FIG. 9A only in the arrangement of the bus bar electrodes 112E. In the following, the same points as those of the electrode configuration of solar cell element 11D shown in FIG. 9A will not be described, and different points will be mainly described.

  As shown in the perspective plan view of FIG. 10, on the surface of the solar cell element 11E, a bus bar electrode 112E and a plurality of finger electrodes 111E crossing the bus bar electrode 112E and parallel to each other are arranged. The bonding member 40 that bonds the bus bar electrode 112E and the tab wiring 20 is arranged so that the bus bar electrode 112E and the tab wiring 20 overlap when the light receiving surface is viewed in a plan view. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 10, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11E, or Is formed in a region facing the finger electrode 111E and the bus bar electrode 112E on the lower surface of the substrate.

  The bus bar electrode 112E is formed of two parallel wires extending in the longitudinal direction where the tab wires 20 are arranged.

  Here, the electrode width W2n of each of the two wires forming the bus bar electrode 112E is wider than the electrode width W1n of the finger electrode 111E.

  Due to the difference in electrode width between the wiring forming the bus bar electrode 112E and the finger electrode 111E, and the correlation between the electrode width and the film thickness by screen printing, the thickness of the finger electrode 111E is determined by the thickness of the wiring forming the bus bar electrode 112E. It becomes thicker than the film thickness.

  Therefore, as shown in the cross-sectional view of FIG. 10, the intersection Px of the bus bar electrode 112E is thicker than the non-intersection Py of the bus bar electrode 112E.

  According to the film thickness distribution in the longitudinal direction of the bus bar electrode 112E, the bus bar electrode 112E and the tab wiring 20 are in contact with or closest to the intersection Px, and the bus bar electrode 112E and the tab wiring 20 are not in the non-crossing part Py. , And are separated by the resin material.

  Furthermore, the conductivity of the bus bar electrode 112E can be improved by arranging a plurality of wirings forming the bus bar electrode 112E by an amount corresponding to the electrode width of the bus bar electrode 112E being smaller than the electrode width of the finger electrode 111E.

  According to the above connection configuration, even if the solar cell element 11E and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical conduction between the bus bar electrode 112E and the tab wiring 20 is ensured, and the conductivity of the bus bar electrode 112E is improved. At the same time, the stress generated in the longitudinal direction due to the difference in the thermal expansion coefficient between the solar cell element 11E and the tab wiring 20 can be reduced. Therefore, the stress of the tab wiring 20 between the solar cell elements 11E and the solar cell element 11E can be reduced.

(Embodiment 3)
[3-1. Connection configuration between collector electrode and tab wiring according to Embodiment 3]
FIG. 11A is a plan view and a cross-sectional view illustrating an electrode configuration of solar cell element 11F according to Embodiment 3. More specifically, FIG. 11A is a perspective plan view and a sectional view in which the vicinity of the surface of the solar cell element 11 in the structural sectional view of FIG. 4 is enlarged.

  As shown in the perspective plan view of FIG. 11A, a bus bar electrode 112F and a plurality of finger electrodes 111F orthogonal to and parallel to the bus bar electrode 112F are arranged on the surface of the solar cell element 11F. The bonding member 40 that bonds the bus bar electrode 112F and the tab wiring 20 is arranged so that the bus bar electrode 112F and the tab wiring 20 overlap when the light receiving surface is viewed in a plan view. Although the bonding member 40 is not shown in the perspective plan view of FIG. 11A, the bonding member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11F. Is formed in a region facing the finger electrode 111F and the bus bar electrode 112F on the lower surface of the.

  Here, the thickness t1n of the plurality of finger electrodes 111F is greater than the thickness t2n of the bus bar electrode 112F.

  The finger electrodes 111F and the bus bar electrodes 112F can be formed by, for example, a printing method such as screen printing. In this case, the finger electrodes 111F and the bus bar electrodes 112F are simultaneously formed using a screen mask that allows the resin-type conductive paste to pass therethrough in a mesh pattern. In the present embodiment, a plurality of times of screen printing are executed when forming the finger electrodes 111F and the bus bar electrodes 112F. For example, the bus bar electrode 112F and the first-layer finger electrode 111F1 are formed by the first screen printing. After that, in the second screen printing, an electrode layer is not formed on the bus bar electrode 112F, and the second layer finger electrode 111F2 is formed only on the first layer finger electrode 111F1.

  According to the above-described manufacturing method, the thickness of the finger electrode 111F becomes larger than the thickness of the busbar electrode 112F without increasing the electrode width of the finger electrode relatively to the busbar electrode. Therefore, it is possible to reduce the light blocking loss as compared with the case where the electrode width of the finger electrode is relatively wide with respect to the bus bar electrode.

  Therefore, as shown in the cross-sectional view of FIG. 11A, the intersection Px of the bus bar electrode 112F is thicker than the non-intersection Py of the bus bar electrode 112F.

  As described above, the tape-shaped or sheet-shaped resin material, which is the adhesive member 40, is softened by being sandwiched between the bus bar electrode 112F and the tab wiring 20 and thermocompression-bonded. Thereby, the tab wiring 20 and the bus bar electrode 112F are joined.

  According to the thickness distribution in the longitudinal direction of the bus bar electrode 112F and the bonding method using the resin material, at the intersection Px, the bus bar electrode 112F and the tab wiring 20 are in contact or closest contact, and at the non-intersection Py, The bus bar electrode 112F and the tab wiring 20 are separated via the resin material.

  According to the above connection configuration, even if the solar cell element 11F and the tab wiring 20 repeat thermal expansion and thermal contraction, the electrical connection between the bus bar electrode 112F and the tab wiring 20 is ensured, and the light blocking loss is reduced. The stress generated in the longitudinal direction can be reduced. Therefore, the stress of the tab wiring 20 and the solar cell element 11F between the solar cell elements 11F is reduced as compared with the case where the bus bar electrode 112F and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the long direction. Can be reduced.

[3-2. Forming Step of Collector Electrode According to Modification of Third Embodiment]
In this modification, a screen printing method having a process different from that of the collector electrode screen printing method described in Embodiment 3 will be described.

  FIG. 11B is a diagram showing a step of forming electrodes of solar cell element 11 </ b> K according to a modification of the third embodiment. The electrode configuration when viewing solar cell element 11K in plan view is the same as the electrode configuration when viewing solar cell element 11F according to Embodiment 3 in plan view.

  As shown in FIG. 11B, a bus bar electrode 112K and a plurality of finger electrodes 111K1 and 111K2 that are orthogonal to and parallel to the bus bar electrode 112K are arranged on the surface of the solar cell element 11K. The plurality of finger electrodes 111K1 are, for example, odd-numbered finger electrodes of all finger electrodes, and the plurality of finger electrodes 111K2 are, for example, even-numbered finger electrodes of all finger electrodes. Electrodes.

  Here, as shown in the AA cross-sectional view of FIG. 11B, the electrode film thickness at the intersection between the plurality of finger electrodes 111K2 and the bus bar electrode 112K is larger than the electrode film thickness of the plurality of finger electrodes 111K1 and the bus bar electrode 112K. thick.

  The finger electrodes 111K1 and 111K2 and the busbar electrode 112K can be formed by, for example, a printing method such as screen printing. In this case, the finger electrodes 111K1 and 111K2 and the bus bar electrode 112K are simultaneously formed by using a screen mask that allows the resin-type conductive paste to pass through the mesh pattern. In the present modification, a plurality of times of screen printing are executed when forming the finger electrodes 111K1 and 111K2 and the bus bar electrode 112K. For example, the first screen printing forms the bus bar electrode 112K and the finger electrode 111K1. Thereafter, finger electrodes 111K2 are formed by the second screen printing.

  According to the above-mentioned manufacturing method, the film thickness of the intersection between the plurality of finger electrodes 111K2 and the bus bar electrode 112K can be reduced without increasing the electrode width of the finger electrode relative to the bus bar electrode. Thicker than thick.

  Therefore, it is possible to reduce the light blocking loss as compared with the case where the electrode width of the finger electrode is relatively wide with respect to the bus bar electrode.

  A tape-shaped or sheet-shaped resin material, which is the adhesive member 40, is thermocompression-bonded to the solar cell element 11 </ b> K thus formed, between the bus bar electrode 112 </ b> K and the tab wiring 20. Thereby, the tab wiring 20 and the bus bar electrode 112K are joined.

  According to the thickness distribution in the longitudinal direction of the bus bar electrode 112K and the bonding method using the resin material, at the intersection between the finger electrode 111K2 and the bus bar electrode 112K, the bus bar electrode 112K and the tab wiring 20 are in contact with each other. The bus bar electrode 112K and the tab wiring 20 are separated from each other via the resin material in other portions.

  According to the above connection configuration, even when the solar cell element 11K and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical continuity between the bus bar electrode 112K and the tab wiring 20 is ensured, and light-blocking loss is reduced, The stress generated in the longitudinal direction can be reduced. Therefore, as compared with the case where the bus bar electrode 112K and the tab wiring 20 are joined by the adhesive member having a uniform thickness in the long direction, the stress of the tab wiring 20 and the solar cell element 11K between the solar cell elements 11K is reduced. Can be reduced.

  In the electrode forming step of the solar cell element according to Embodiment 3 and its modifications, the material of the conductive paste used is, for example, a conductive paste containing at least one of Ag, Cu, and Ni; A conductive paste containing conductive particles such as Ni powder or Ag-coated Cu powder may be used. It is not necessary to use the same conductive paste material for the first screen printing and the second screen printing. For example, in the first screen printing in which the bus bar electrode and (part of) the finger electrode are formed, a conductive paste material (Ag paste) having a low resistivity is used to give priority to current collection efficiency, and the finger electrode (one part) is used. In the second screen printing in which only the second part is formed, a conductive paste material (a conductive paste containing Ag-coated Ni powder or Ag-coated Cu powder) having a relatively high resistivity in consideration of cost is used. May be used.

(Other embodiments)
As described above, the solar cell module according to the present invention has been described based on the first to third embodiments and their modifications, but the present invention is not limited to the above-described embodiments and their modifications. .

  For example, in the first to third embodiments and their modifications, the solar cell elements 11 and 11A to 11K only need to have a function as a photovoltaic voltage, and are not limited to the structure of the solar cell element.

  Further, in the above-described first to third embodiments and their modifications, the configuration in which the electrode configuration having the above-described characteristics is applied to the surface of the solar cell element has been described. May be applied only to the back surface of the solar cell element, or to both the front surface and the back surface.

  Further, the bus bar electrode and the finger electrode need not be straight lines but may be curved lines.

  In the solar cell module according to the above-described embodiment, a configuration in which a plurality of solar cell elements are arranged in a matrix in a plane has been described, but the invention is not limited to the matrix. For example, an annular arrangement or a configuration arranged in a one-dimensional linear or curved shape may be used.

  In addition, a form obtained by applying various modifications conceived by those skilled in the art to the above-described first to third embodiments and their modifications, and first to third embodiments and their modifications without departing from the spirit of the present invention. Embodiments realized by arbitrarily combining the components and functions in the examples are also included in the present invention.

  In addition, as a solar cell module according to another embodiment, the following electrode configuration is exemplified. The basic configuration and the like of the solar cell module according to the present embodiment are the same as those according to the first to third embodiments, and thus description thereof is omitted. Hereinafter, the electrode configuration of solar cell element 11G different from the first embodiment and The description will focus on the sectional structure.

  FIG. 12 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element 11G according to another embodiment.

  As shown in the perspective plan view of FIG. 12, two parallel busbar electrodes 112G and a plurality of finger electrodes 111G that are orthogonal to and parallel to the busbar electrodes 112G are arranged on the surface of the solar cell element 11G. . However, the bonding member 40 that bonds the finger electrode 111G and the tab wiring 20 is arranged so that the two bus bar electrodes 112G and the tab wiring 20 do not overlap when the light receiving surface is viewed in a plan view. Although the adhesive member 40 is not shown in the perspective plan view of FIG. 12, the adhesive member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11G. Is formed in a region facing the finger electrode 111G on the lower surface of the substrate.

  As described above, the tape-shaped or sheet-shaped resin material serving as the adhesive member 40 is softened by being thermocompressed while being sandwiched between the finger electrode 111G and the tab wiring 20, for example. Thereby, the tab wiring 20 and the finger electrode 111G are joined.

  By joining the tab wiring 20 and the finger electrode 111G with the above-mentioned resin material, the finger electrode 111G and the tab wiring 20 are in contact or closest contact with each other at the overlapping portion of the tab wiring 20 and the finger electrode 111G, and at the non-overlapping portion, The tab wiring 20 and the surface of the solar cell element 11G are separated via the resin material. If the finger electrode 111G and the tab wiring 20 are electrically connected to each other in the overlapping portion, the received charge generated in the solar cell element 11G and collected by the finger electrode 111G is transmitted to the tab wiring 20. Is possible. For this reason, in the non-overlapping part, the surface of the solar cell element 11G and the tab wiring 20 need not be bonded via the bonding member 40.

  According to the above connection configuration, even when the solar cell element 11G and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical conduction between the finger electrode 111G and the tab wiring 20 is ensured, and the solar cell element 11G and the tab wiring 20 are maintained. The stress generated in the longitudinal direction of the tab wiring 20 due to the difference in the coefficient of thermal expansion from that of the tab wiring 20 can be reduced. Therefore, the stress of the tab wiring 20 between the solar cell elements 11G and the stress of the solar cell element 11G can be reduced as compared with the case where the bus bar electrode and the tab wiring are joined by the adhesive member having a uniform thickness over the long direction. .

  In FIG. 12, a configuration in which the bus bar electrode 112G is not formed may be employed.

  FIG. 13 is a plan view and a cross-sectional view illustrating an electrode configuration of a solar cell element 11L according to another embodiment.

  As shown in the perspective plan view of FIG. 13, on the surface of the solar cell element 11L, there are no bus bar electrodes, and a plurality of finger electrodes 111G parallel to each other are arranged. As shown in the sectional view of FIG. 13, an adhesive member 40 for adhering the plurality of finger electrodes 111G and the tab wiring 20 is arranged. Although the bonding member 40 is not shown in the perspective plan view of FIG. 13, the bonding member 40 is formed on the entire lower surface of the tab wiring 20 facing the solar cell element 11L, or Is formed in a region facing the finger electrode 111G on the lower surface of the substrate.

  By joining the tab wiring 20 and the finger electrode 111G with the above-described resin material, the finger electrode 111G and the tab wiring 20 are in contact or closest contact with each other at the overlapping portion of the tab wiring 20 and the finger electrode 111G, and at the non-overlapping portion, The tab wiring 20 and the surface of the solar cell element 11L are separated via the resin material. According to the above connection configuration, even when the solar cell element 11L and the tab wiring 20 repeat thermal expansion and thermal contraction, electrical conduction between the finger electrode 111G and the tab wiring 20 is ensured, while the solar cell element 11L and the tab wiring 20 are maintained. The stress generated in the longitudinal direction of the tab wiring 20 due to the difference in the coefficient of thermal expansion from that of the tab wiring 20 can be reduced. Therefore, the stress of the tab wiring 20 between the solar cell elements 11L and the stress of the solar cell element 11L can be reduced as compared with the case where the bus bar electrode and the tab wiring are joined by the adhesive member having a uniform thickness in the long direction. .

  Further, in addition to the electrode configuration of the solar cell element 11L illustrated in FIG. 13, the electrode width of the finger electrode 111G in the end region Ap is different from the electrode configuration of the finger electrode 111G in the central region Ac, as in the configuration of the finger electrode illustrated in FIG. 9B. Or the thickness of the finger electrode 111G in the end region Ap may be larger than the thickness of the finger electrode 111G in the central region Ac.

  When the tab wiring 20 is adhered to the finger electrode 111G having the above-described electrode film thickness relationship, the distance between the tab wiring 20 and the surface of the solar cell element in the non-overlapping portion of the end region Ap is equal to the center region Ac. The distance is larger than the distance between the tab wiring 20 and the surface of the solar cell element in the non-overlapping portion.

  Therefore, the adhesive strength between the tab wiring 20 and the solar cell element in the non-overlapping portion of the end region Ap is lower than the adhesive strength between the tab wiring 20 and the solar cell element in the non-overlapping portion of the end region Ac. .

  According to the above connection configuration, even if the solar cell element 11L and the tab wiring 20 repeatedly undergo thermal expansion and thermal contraction, electrical conduction between the finger electrode 111G and the tab wiring 20 is maintained, while the solar cell element 11L and the tab wiring 20 are maintained. The stress generated in the longitudinal direction due to the difference in the coefficient of thermal expansion from 20 can be reduced in the end region Ap of the solar cell element 11L. Therefore, in particular, in the end region Ap where the tab wiring 20 is easily subjected to stress, the stress of the tab wiring 20 and the solar cell element 11L between the solar cell elements 11L can be reduced more effectively.

DESCRIPTION OF SYMBOLS 1 Solar cell module 11, 11A, 11B, 11C, 11D, 11E, 11F, 11G, 11H, 11J, 11K, 11L Solar cell element 20 Tab wiring 40 Adhesive member 111, 111A, 111B, 111C, 111CC, 111CP, 111D, 111E, 111F, 111F1, 111F2, 111G, 111HC, 111HP, 111J, 111K1, 111K2 Finger electrodes 112, 112A, 112B, 112C, 112D, 112E, 112F, 112G, 112H, 112JC, 112JP, 112K Busbar electrodes

Claims (9)

Two solar cell elements adjacent in a direction parallel to the light receiving surface,
A wiring member that is disposed on one surface and the other back surface of the two solar cell elements and electrically connects the two solar cell elements;
A plurality of finger electrodes formed on the front surface and the back surface, and collecting received light charges generated by the solar cell element,
A bus bar electrode that is formed to extend in a direction intersecting each of the plurality of finger electrodes on the front surface and the back surface, and electrically connects the plurality of finger electrodes;
An adhesive member that adheres the bus bar electrode and the wiring member so that the bus bar electrode and the wiring member overlap when the light receiving surface is viewed in a plan view,
In at least one end region of the front surface and the back surface, a film thickness of an intersection portion of the bus bar electrode that intersects with the finger electrode is larger than a film thickness of a portion sandwiched between the adjacent intersection portions of the bus bar electrode. Thick,
In one even without prior Kisukuna, the thickness of the intersecting portion of the bus bar electrode in the edge region is greater than the thickness of the crossing portion of the bus bar electrode in the central region,
The wiring member has a curved portion between the two solar cell elements,
Solar cell module. Two solar cell elements adjacent in a direction parallel to the light receiving surface,
A wiring member that is disposed on one surface and the other back surface of the two solar cell elements and electrically connects the two solar cell elements;
A plurality of finger electrodes formed on the front surface and the back surface, and collecting received light charges generated by the solar cell element,
A bus bar electrode that is formed to extend in a direction intersecting each of the plurality of finger electrodes on the front surface and the back surface, and electrically connects the plurality of finger electrodes;
An adhesive member that adheres the bus bar electrode and the wiring member so that the bus bar electrode and the wiring member overlap when the light receiving surface is viewed in a plan view,
In at least one end region of the front surface and the back surface, a film thickness of an intersection portion of the bus bar electrode that intersects with the finger electrode is larger than a film thickness of a portion sandwiched between the adjacent intersection portions of the bus bar electrode. Thick,
In one even without prior Kisukuna, electrode thickness in the non-intersection of the finger electrodes and the bus bar electrode in the end region is thinner than the electrode thickness in the non-intersection of the finger electrodes and the bus bar electrode in the central region,
The wiring member has a curved portion between the two solar cell elements,
Solar cell module. Two solar cell elements adjacent in a direction parallel to the light receiving surface,
A wiring member that is arranged on one surface and the other back surface of the two solar cell elements and electrically connects the two solar cell elements;
A plurality of finger electrodes formed on the front surface and the back surface, and collecting received light charges generated by the solar cell element,
A bus bar electrode formed on the front surface and the back surface so as to extend in a direction intersecting with each of the plurality of finger electrodes, and electrically connecting the plurality of finger electrodes;
An adhesive member that adheres the bus bar electrode and the wiring member so that the bus bar electrode and the wiring member overlap when the light receiving surface is viewed in a plan view,
In at least one end region of the front surface and the back surface, a film thickness of an intersection portion of the bus bar electrode that intersects with the finger electrode is larger than a film thickness of a portion sandwiched between the adjacent intersection portions of the bus bar electrode. Thick,
The wiring member has a curved portion between the two solar cell elements,
Only in the end regions of the one of the central region and the edge region even without prior Kisukuna, the thickness of the intersecting portion of the bus bar electrode, the film of the sandwiched by intersection adjacent portions of the bus bar electrode Thicker than thicker solar module. The solar cell module according to any one of claims 1 to 3, wherein an electrode width of the finger electrode at the intersection is wider than an electrode width of another part of the finger electrode. The solar cell module according to claim 1, wherein an electrode width of the bus bar electrode is smaller than an electrode width of the finger electrode. The solar cell module according to claim 1, wherein a thickness of the plurality of finger electrodes is greater than a thickness of the bus bar electrode. The adhesive member is a resin,
The solar cell module according to any one of claims 1 to 6, wherein the resin is interposed between the bus bar electrode and the wiring member. The solar cell module according to claim 7, wherein the bus bar electrode and the wiring member intermittently contact in the direction. Two solar cell elements adjacent in a direction parallel to the light receiving surface,
A wiring member that is disposed on one surface and the other back surface of the two solar cell elements and electrically connects the two solar cell elements;
A plurality of finger electrodes formed on the front surface and the back surface, and collecting received light charges generated by the solar cell element,
An adhesive member that adheres the plurality of finger electrodes and the wiring member so that the plurality of finger electrodes and the wiring member intersect when the light receiving surface is viewed in a plan view,
In the central region and the end region of at least one of the front surface and the rear surface, the thickness of the finger electrode in the end region is larger than the thickness of the finger electrode in the central region.
Solar cell module.

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