JP2014229663A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solar cell module in which bonding of a tab wire and an electrode can be facilitated and bond strength can be enhanced while forming an electrode by using a paste such as an adhesive.SOLUTION: A solar cell module includes a first solar cell 60a having a surface electrode 36, formed of a conductive paste, on the light-receiving surface side, a second solar cell 60b arranged adjacently to the first solar cell 60a on the first direction side, and having a back electrode 37 formed on the back side 62, i.e., the reverse side of the light-receiving surface, a tab wire 34 extending in the first direction and being bonded to the surface electrode 36 of the first solar cell 60a, and the back electrode 37 of the second solar cell 60b, and a plurality of metal pieces 38 being bonded onto a region to which the tab wire 34 of the surface electrode 36 is bonded.

Description

  The present invention relates to a solar cell module having a strip-shaped tab wire that connects a solar cell and another adjacent solar cell in series.

  2. Description of the Related Art Conventionally, a solar battery module is used in which a plurality of solar cells each having a surface electrode on a surface forming a light receiving surface and a back electrode on a back surface are arranged side by side. In such a solar cell module, in order to connect one solar cell and another solar cell adjacent thereto in series, the surface electrode of one solar cell and the other solar cells adjacent to each other A strip-shaped tab line connecting the back electrode may be used.

  Generally, the strip-shaped tab wire is arranged extending in the connecting direction on the front surface and the back surface of the solar battery cell. The tab wire is made of a highly conductive metal, such as copper foil, coated with solder. In the connection of the tab wire, the tab wire is arranged and heated on the electrode such as the front surface electrode and the back surface electrode, and the tab wire and the solar battery cell are crimped partially or over the entire length to connect the electrode and the tab wire Figured. The heating at the time of this crimping may be performed at a temperature of about 200 to 400 ° C.

  Here, there is a solar battery cell in which amorphous silicon is stacked on a silicon wafer as one means for improving the efficiency of the solar battery cell. Due to the nature of amorphous silicon, it is difficult to perform electrode firing at a temperature of about 200 to 400 ° C. when manufacturing an electrode of a solar battery cell. Therefore, for example, Patent Document 1 discloses a technique for forming an electrode using an adhesive containing conductive particles.

JP 2002-270863 A

  However, in the electrode formation using the adhesive, the area of the conductive particles exposed on the electrode surface is easily reduced by the adhesive covering the surface of the electrode. For this reason, the joint area between the tab wire and the electrode is reduced during soldering, and it is difficult to ensure sufficient solder wettability. If sufficient solder wettability cannot be obtained, the solder joint strength will be low, and it may be difficult to maintain connection reliability against the stress caused by temperature changes in the installation environment of the solar cell module. .

  The present invention has been made in view of the above, and can facilitate the joining of the tab wire and the electrode and improve the joining strength while forming the electrode using a paste such as an adhesive. It aims at obtaining a solar cell module.

  In order to solve the above-described problems and achieve the object, the present invention provides a first solar cell in which a surface electrode is formed on the light-receiving surface side with a conductive paste containing conductive particles, and a first solar cell. A second solar cell disposed adjacent to the battery cell on the first direction side and having a back electrode formed on the back surface opposite to the light receiving surface, and extending along the first direction, A tab wire bonded to the front surface electrode of the first solar battery cell, the back surface electrode of the second solar battery cell, and a plurality of metal pieces bonded to a region of the surface electrode where the tab line is bonded; It is characterized by providing.

  According to the present invention, the metal piece on the surface electrode is electrically and mechanically joined to the conductive particles in the conductive paste. Further, the soldering between the metal piece and the tab wire can be easily performed. Therefore, conventionally, even when the electrode is formed with a conductive paste that is covered with a conductive paste and the area of the conductive particles that can be soldered on the electrode surface is likely to be small, it is easy to join the tab wire. And improvement in bonding strength can be achieved.

FIG. 1 is a perspective view of a solar cell module according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a solar battery cell included in the solar battery module as viewed from the surface. FIG. 3 is a bottom view of a solar battery cell included in the solar battery module as seen from the back side. 4 is a cross-sectional view taken along the line BB shown in FIG. FIG. 5 is a cross-sectional view taken along the line CC shown in FIG. FIG. 6 is a partial cross-sectional view of a portion A of the solar cell panel shown in FIG. FIG. 7 is a plan view of a solar battery cell with tab wires joined thereto.

  Below, the solar cell module concerning embodiment of this invention is demonstrated in detail based on drawing. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a solar cell module 80 according to the first embodiment of the present invention. The solar cell module 80 includes a solar cell panel 70 formed by resin-sealing a plurality of solar cells 60 (60a, 60b) arranged vertically and horizontally on the XY plane in the figure, and the outer edge of the solar cell panel 70 all around the periphery. And a frame member 10 surrounding the frame member 10.

  The several photovoltaic cell 60 is connected in series along the X direction which is a 1st direction by the tab wire mentioned later. In addition, depending on the site | part of the solar cell panel 70, there also exists a location where the photovoltaic cell 60 is connected along the Y direction.

  The frame member 10 is made by extrusion molding of aluminum or the like, and covers the outer edge of the solar cell panel 70 over the entire circumference with a U-shaped portion having a U-shaped cross section. The frame member 10 is fixed to the solar cell panel 70 via a butyl-based sealing material or a silicon-based adhesive, and reinforces the solar cell panel 70, and the solar cell panel 70 is used in a building such as a house or a building. It should be attached to a stand (not shown) provided.

  FIG. 2 is a plan view of the solar battery cell 60 included in the solar battery module 80 as viewed from the surface 61. FIG. 3 is a bottom view of the solar battery cell 60 included in the solar battery module 80 as seen from the back surface 62. 4 is a cross-sectional view taken along the line BB shown in FIG. FIG. 5 is a cross-sectional view taken along the line CC shown in FIG.

  For the solar cell 60, an n-type silicon substrate having a thickness of about 100 to 300 μm is used. A P-type amorphous layer and an n-type amorphous layer are formed on the silicon substrate.

  As shown in FIGS. 2 and 4, a surface-treated light receiving surface is formed on the surface 61 of the solar battery cell 60. On the light receiving surface, a surface grid electrode 33 and a surface bus electrode 36 are provided as surface electrodes for extracting electric energy converted by the solar battery cell 60.

  A plurality of the surface grid electrodes 33 are formed in parallel in a direction orthogonal to the first direction (X direction) that is the connection direction of the solar cells 60. The surface grid electrode 33 is formed over the entire surface 61 of the solar battery cell 60 in order to take out the electric power generated on the light receiving surface without waste.

  The surface bus electrode 36 is formed so as to be orthogonal to the surface grid electrode 33, that is, to extend in parallel with the connection direction of the solar battery cells 60. In the present embodiment, two surface bus electrodes 36 are formed.

  The surface grid electrode 33 and the surface bus electrode 36 are formed using a conductive paste containing conductive particles, for example, a conductive adhesive. The surface grid electrode 33 is formed by applying a plurality of conductive adhesives to the surface 61 of the solar battery cell 60 in a linear shape having a width of about 100 μm. The surface grid electrodes 33 are formed with an interval of about 2 mm.

  The surface bus electrode 36 is formed by applying a conductive adhesive to the surface 61 of the solar battery cell 60 in a strip shape having a width of about 1 mm. The surface bus electrode 36 is formed at a distance of a quarter of the cell width from the end of the solar battery cell 60 so as to be orthogonal to the surface grid electrode 33. The surface grid electrode 33 and the surface bus electrode 36 thus formed are electrically connected.

  A plurality of copper pieces (metal pieces) 38 are arranged on the surface bus electrode 36 (on the region of the surface electrode where the tab line is joined). Since the copper piece 38 is disposed after the application of the conductive adhesive, when the adhesive is dried, the copper piece 38 is bonded onto the surface bus electrode 36 and mechanically connected. Moreover, the surface bus electrode 36 and the surface grid electrode 33, and the copper piece 38 will be electrically connected by contacting the conductive particles contained in the conductive adhesive.

  As shown in FIGS. 3 and 5, the back surface 62 (surface opposite to the front surface 61) of the solar battery cell 60 is provided with a back surface collecting grid electrode 32 and a back surface tab line connecting electrode 37 as back surface electrodes. Yes.

  A plurality of back surface collecting grid electrodes 32 are formed in parallel in a direction orthogonal to the first direction (X direction) which is the connection direction of solar cells 60. The back surface collecting grid electrode 32 is formed over the entire back surface 62 of the solar battery cell 60.

  The back surface tab line connection electrode 37 is formed so as to be orthogonal to the back surface current collecting grid electrode 32, that is, to extend in parallel with the connection direction of the solar cells 60. In the present embodiment, two back surface tab line connection electrodes 37 are formed.

  The back surface collecting grid electrode 32 and the back surface tab line connecting electrode 37 are formed in the same manner as the front surface grid electrode 33 and the front surface bus electrode 36 by using a conductive paste containing conductive particles, for example, a conductive adhesive. .

  A plurality of copper pieces (metal pieces) 38 are disposed on the back surface tab line connection electrode 37 (on the region of the back surface electrode where the tab line is joined). Since the copper piece 38 is disposed after application of the conductive adhesive, when the adhesive is dried, the copper piece 38 is bonded to the back surface tab line connecting electrode 37 and mechanically connected. Moreover, the back surface tab wire connection electrode 37 and the back surface current collecting grid electrode 32 and the copper piece 38 are electrically connected by contacting with the conductive particles contained in the conductive adhesive.

  FIG. 6 is a partial cross-sectional view of a portion A of the solar cell panel 70 shown in FIG. FIG. 7 is a plan view of the solar battery cell 60 to which the tab wire is joined. In addition, the cut surface of a partial sectional view is along the BB line shown in FIG. In FIG. 6, the thickness of elements constituting the solar cell panel 70 is exaggerated. Further, one of the solar cells 60 adjacent in the X direction will be described as a solar cell 60a (first solar cell) and the other as a solar cell 60b (second solar cell).

  The laminated body constituting the solar battery panel 70 includes a glass layer 21 made of transparent glass, a plurality of solar battery cells 60 (60a, 60b), and a tab wire that connects these solar battery cells 60 in series from the light receiving surface side. A cell arrangement layer 25 in which 34 is sealed with a resin such as EVA and a backsheet layer 23 made of PET, PVF (polyvinyl fluoride) or the like and having excellent weather resistance are laminated in this order. In FIG. 6, the hatching of the glass layer 21, the cell arrangement layer 25, and the back sheet layer 23 is omitted.

  One end of the tab wire 34 is joined to the front surface bus electrode 36 of the solar battery cell 60a, and the other end is connected to the back surface tab line connecting electrode 37 of the solar battery cell 60b. At this time, the tab wire 34 is solder-bonded to the copper piece 38 adhered on the front surface bus electrode 36 and the copper piece 38 adhered on the back surface tab line connecting electrode 37.

  Unlike the conductive adhesive constituting the front surface bus electrode 36 and the back surface tab line connection electrode 37, the copper piece 38 is not covered with the adhesive, so that the oxide film can be easily removed by supplying the flux. It is possible to achieve solder joints with good wettability.

  Therefore, compared with the case where the copper piece 38 is not provided on the front surface bus electrode 36 and the back surface tab line connection electrode 37, the electrical and mechanical joining between the front surface electrode and the back surface electrode and the tab wire 34 is facilitated. In addition, the bonding strength can be improved.

  In the present embodiment, only the connection between two adjacent solar battery cells 60a and 60b has been described, but actually, a plurality of solar battery cells 60 are connected in series by repeating the same connection. Is done.

  Moreover, although the copper piece which used copper was mentioned and demonstrated as a metal piece adhere | attached on the surface bus electrode 36 and the back surface tab line connection electrode 37, it is not restricted to this, You may use another metal. For example, a silver piece using silver, an aluminum piece using aluminum, or an aluminum alloy piece using an aluminum alloy may be used.

  As described above, the solar cell module according to the present invention is suitable for being applied to a solar cell module having a strip-shaped tab line that connects another solar cell adjacent to the solar cell in series.

  10 frame member, 21 glass layer, 23 back sheet layer, 25 cell arrangement layer, 32 back surface collecting grid electrode (back surface electrode), 33 surface grid electrode (surface electrode), 34 tab wire, 36 surface bus electrode (surface electrode) ), 37 Back surface tab wire connection electrode (back surface electrode), 38 Copper piece (metal piece), 60 solar cell, 60a solar cell (first solar cell), 60b solar cell (second solar cell) Cell), 61 surface, 62 back surface, 70 solar cell panel, 80 solar cell module.

Claims (5)

A first solar cell in which a surface electrode is formed on the light receiving surface side with a conductive paste containing conductive particles;
A second solar cell that is arranged adjacent to the first direction side with respect to the first solar cell and has a back electrode formed on the back side opposite to the light receiving surface;
A tab line that extends along the first direction and is joined to the surface electrode of the first solar cell and the back electrode of the second solar cell;
A solar cell module comprising: a plurality of metal pieces adhered on a region of the surface electrode to which the tab wire is bonded. The back electrode is formed of a conductive paste containing conductive particles,
2. The solar cell module according to claim 1, further comprising a plurality of metal pieces bonded on a region of the back electrode to which the tab wire is bonded.   The solar cell module according to claim 1, wherein the metal piece is copper.   The solar cell module according to claim 1, wherein the metal piece is silver.   The solar cell module according to claim 1, wherein the metal piece is aluminum or an aluminum alloy.

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