JP2008235818A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module for improving productivity by suppressing cell cracks. <P>SOLUTION: The solar cell module has a first solar cell C<SB>11</SB>where busbar electrodes 21a, 21b with a first direction as a longitudinal direction are arranged on a main surface; a connection member 12 for electrically connecting the first solar cell C<SB>11</SB>crossing the busbar electrodes 21a, 21b on the main surface of the first solar cell C<SB>11</SB>and a second solar cell C<SB>21</SB>adjacent to a second direction substantially orthogonally crossing the first direction; and cushionings 13a-13e inserted into at least one portion between the connection member 12 and the main surface of the solar cell C<SB>11</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device that is sensitive to infrared rays, visible light, and short-wave electromagnetic waves, and more particularly to a solar cell module that converts these radiation energy into electrical energy.

  Solar cells are attracting attention as a new environmentally friendly energy source because they can directly convert light from the sun, a clean and inexhaustible energy source, into electricity.

  When such a solar battery is used as a power source (energy source), the output per solar battery cell is about several watts at most, so it is not used for each solar battery cell, but as shown below. In general, it is used as a solar cell module in which a plurality of solar cells are arranged in a matrix and these are electrically connected in series to increase the output to 100 W or more (for example, see Patent Document 1). ).

  First, a predetermined number of solar cells are arranged along a straight line, and a plurality of strings are formed by connecting them in series with tab wiring extending in the direction of the straight line. Then, a plurality of strings are arranged in the short direction substantially perpendicular to the straight line, and the tab wirings on the solar cells located at the ends of the adjacent strings are electrically connected by a connecting member extending in the short direction. . As described above, a plurality of solar cells arranged in a matrix can be connected in series.

Further, the applicant arranges the electrodes of different polarities of the solar cells located at the ends of the adjacent strings so as to face in the same direction, and the connecting member is arranged on the main surface of the solar cells. There has been proposed a solar cell module adhered to a tab wiring on the back surface side of a solar cell located at an end (Japanese Patent Application No. 2006-99978). The tab wiring extending in the straight direction and the connecting member extending in the short direction intersect on the main surface of the first solar cell, and are electrically connected to each other at the intersecting portion.
JP 2006-278904 A

  However, since the thickness of the intersection between the connecting member and the tab wiring is increased compared to other portions of the main surface of the first solar cell, the tab wiring, the connecting member, and the solar cell are embedded with a filler. During the laminating process, stress may concentrate on the intersecting portion and cell cracks may occur. Moreover, a cell crack may generate | occur | produce when a connection member and the main surface of a photovoltaic cell contact directly.

  The objective of this invention is providing the solar cell module which suppressed the cell crack and improved productivity.

  A feature of the present invention is that a first solar cell in which a bus bar electrode having a first direction as a longitudinal direction is disposed on a main surface, and the bus bar electrode intersects with the main surface of the first solar cell. A connecting member that electrically connects the first solar cell and a second solar cell adjacent to a second direction substantially orthogonal to the first direction; and the connecting member And a cushioning material inserted in at least a portion between the main surface of the first solar cell and the gist of the present invention.

  In the characteristics of the present invention, it is desirable that the buffer material is bonded to the main surface of the connection member and the first solar battery cell.

  In the feature of the present invention, it is desirable that the cushioning material is embedded without a gap between the connecting member and the main surface of the first solar battery cell.

  In the feature of the present invention, it is desirable that the buffer material is made of a thermoplastic resin.

  By inserting a buffer material between the connection member and the main surface of the first solar battery cell, pressure concentration at the intersection between the connection member and the bus bar electrode can be suppressed. Moreover, it can suppress that a connection member and the main surface of a photovoltaic cell contact directly by inserting a buffer material. Therefore, cell cracking due to stress concentration at the intersection or direct contact between the connecting member and the solar battery cell can be suppressed. Therefore, according to this invention, the solar cell module which suppressed the cell crack and improved productivity can be provided.

  When the interface between the connection member and the first solar battery cell is in an unadhered state, gas stays at the interface due to this. Appearance defects of the solar cell module occur due to gas retention. Therefore, by adhering the buffer material to the main surface of the connection member and the first solar battery cell, the interface between the connection member and the first solar battery cell can be brought into an adhesive state, so outgas stays at the interface. Can be suppressed. Therefore, the appearance defect of the solar cell module due to gas retention can be suppressed.

  By embedding the buffer material between the connecting member and the main surface of the first solar cell without a gap, stress concentration at the intersection between the connecting member and the bus bar electrode and direct contact between the connecting member and the solar cell are further increased. Can be suppressed. Further, since the buffer material is adhered to the entirety between the connection member and the main surface of the first solar battery cell, the generation of member outgas at the interface and the outgas retention at the interface are further suppressed. can do.

  Since the thermoplastic resin softens when heated and becomes easy to mold, the cushioning material is made of a thermoplastic resin, so that the cushioning material can be inserted between the connecting member and the main surface of the first solar cell by a simple method. Can be made.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals.

With reference to FIG. 1, the structure of the solar cell module concerning embodiment of this invention is demonstrated. The solar cell module includes a plurality of solar cell groups G _{1 to} G _{n formed} by electrically connecting a predetermined number of solar cells arranged in the first direction (X direction) in series, and a plurality of solar cells. And a connection member 12 that electrically connects the battery groups G _{1 to} G _n in series. FIG. 1 illustrates a case where the solar cell module includes n solar cell groups. The n solar cell groups are referred to as first to nth solar cell groups G _{1 to} G _n . A translucent surface member and a back surface cover material are bonded to the light receiving surface side and the back surface side of these solar cell groups G _{1 to} G _n via a sealing resin (not shown).

Each of the _{first to} n-th solar cell groups G _{1 to} G _n electrically connects a predetermined number of solar cells and a predetermined number of solar cells arranged in the X direction in series. Tab wiring 11a, 11b is provided. Solar cell groups _G 1 ~G _n of first through n in FIG. 1 will be described the case where each comprising k number of the solar cell _C 1 -C _k. The first solar cell group _{G 1} includes a solar cell _C 11 _{-C 1k,} the second solar cell group _{G 2} comprises a solar cell _C 21 _{-C 2k.} Similarly, the third to n-th solar cell groups G _{3 to} G _n include solar cells C _{31 to} C _3k ,..., C _{n1 to} C _nk .

The k solar cells C _{11 to} C _1k included in the first solar cell group G ₁ are arranged in order along the first direction (X direction). In each of the solar cells C _{11 to} C _1k , electrodes having different polarities are provided on the first main surface and the second main surface facing the first main surface, respectively. The k solar cells C _{11 to} C _1k are alternately arranged so that electrodes having different polarities in adjacent solar cells face the same direction. The solar cells C _{11 to} C _{1k each} have a photoelectric conversion unit that generates a photogenerated carrier by light incidence from both surfaces of the first and second main surfaces, and a positive / negative sign for taking out the photogenerated carrier generated by the photoelectric conversion unit. A pair of electrodes. A pair of positive and negative electrodes is provided on each of the first main surface and the second main surface. Here, a case where the positive electrode is formed on the first main surface side and the negative electrode is formed on the second main surface side will be described. The positive electrode of the solar cell _{C 11} (first main surface), a negative electrode (second main surface) of the solar cell _{C 12,} the positive electrode (first main surface) of the solar cell _{C 13,} · · · solar cell The positive electrodes (first main surfaces) of the cells C _1k are arranged to face the same direction.

k pieces of the solar cell C ₁₁ -C _1k are electrically connected in series two of the wiring member 11a, 11b is the same side of the first solar cell and the third solar cells adjacent in the X direction By connecting the electrodes exposed on the surface, the first solar cell and the third solar cell adjacent in the X direction are electrically connected in series. 2 of the wiring member 11a, 11b, respectively, connected between the negative electrode exposed to the surface side of the positive electrode and the solar cell C ₁₂ which is exposed on the surface side of the solar cell C _11, the solar cell C ₁₂ connects between the negative electrode which is exposed to the outside on the back side of the positive electrode and the solar cell C ₁₃ which is exposed to the outside on the back side, ..., the solar cell C _1k-1 on the back side to the exposed the positive electrode and the solar cell The negative electrode exposed on the back side of C _1k is connected.

The k solar cells C _{1 to} C _k and the tab wirings 11a and 11b included in the other second to nth solar cell groups G _{2 to} G _n are also the first except for the differences shown below. a solar cell group _{G 1} comprises k number of solar cells _C 11 _{-C 1k} and the wiring member 11a, the same structure as 11b. The difference is that the second, fourth, sixth, ..., the solar cell group _G 2 of the second _n, G _4, G 6, ..., in _{G n,} the negative electrode of the solar cell _{C 1} (second main surface) of the solar cell C ₂ positive electrode (first main surface), a negative electrode (second main surface of the solar cell C _3), the negative electrode of the ... solar cell C _k (second main Are arranged in the same direction. That is, the order of replacement of the negative electrode and the positive electrode in the even-numbered solar cell groups G ₂ , G ₄ , G ₆ ,..., _Gn is changed to the odd-numbered solar cell groups G ₁ , G ₃ , G ₅ ,. • Reverse for G _n−1 .

The first to n-th solar cell groups G _{1 to} G _n are in order in the short direction (second direction: Y direction) of the solar cell group substantially perpendicular to the first direction (X direction). Are listed. Therefore, the solar cell C _{11 (the} first solar cell) and the solar cell C ₂₁ located in the second end of the solar cell group G _{2 (second} located at a first end of the solar cell group G ₁ The solar cells) are arranged so that electrodes having different polarities face in the same direction. That is, the positive electrode of the solar cell C ₁₁ in the surface side of the solar cell module (first principal surface) and a negative electrode of the solar cell C ₂₁ (second main surface) is placed. Similarly, solar cell C _2k (first solar cell) located at one end of _second solar cell group G ₂ and solar cell C _3k (first solar cell) located at one end of _third solar cell group G ₃ 2 solar cells) are arranged such that electrodes of different polarities face in the same direction, ..., solar cells C _n- positioned at one end of the ( _{n-1) th} solar cell group _{Gn-1. 11} (first solar battery cell) and solar battery cell C _n1 (second solar battery cell) located at one end of _n-th solar battery group G _n so that electrodes having different polarities face the same direction. Be placed.

The connection member 12 electrically connects the two solar cell groups G _{1 to} G _n adjacent in the Y direction in series. The connecting member 12 electrically connects the first solar cell and the second solar cell located at one end of each of the two solar cell groups G _{1 to} G _n adjacent in the Y direction in series. The first solar cell and the second solar cell located at one end of two solar cell groups G _{1 to} G _n adjacent in the Y direction are arranged such that electrodes having different polarities face the same direction. Therefore, the connection member 12 connects the electrodes exposed on the back surface side or the front surface side of the solar cell module. In the example of FIG. 1, it has shown about the case where the electrode exposed on the back surface side, ie, the anti-light-receiving surface side, of a solar cell module is connected. Connecting member 12, respectively, between the solar cells _{C 11} and the solar cell _{C 21,} between the solar cells _{C 2k} and the solar cell _{C 3k,} between solar cells _{C 31} and the solar cell _{C 41,} · .... Between the photovoltaic cell Cn _-11 and the photovoltaic cell _Cn1 is connected in series. In this way, the connection member 12 electrically connects the _{first to nth} solar cell groups G _{1 to} G _n in series.

  The solar cell module has a cell structure in which solar cells are arranged in a k × n matrix. A region where the k × n solar cells are arranged is referred to as a “cell region”. The connection member 12 connects between the first solar cell and the second solar cell adjacent in the Y direction within this cell region.

Solar cell modules C _1k and C _nk located at both ends of a series of first to n-th solar cell groups G _{1 to} G _n electrically connected in series by the connecting member 12 include solar cell modules. An output terminal T1 and an output terminal T2 for taking out the electric power generated by are connected to each other.

  The solar cell module further includes a thermoplastic filler that surrounds the components shown in FIG. 1, and a surface protective material and a back surface protective material bonded by the filler. In FIG. 1, the display of the filler, the surface protective material, and the back surface protective material is omitted, but the cross-sectional configuration thereof will be described with reference to FIG. 3.

FIG. 2 is an enlarged plan view showing the configuration of the back surface side of the solar cells C ₁₁ and C ₂₁ located at one end of the first solar cell groups G ₁ and G ₂ . Referring to FIG. 2, the configuration of the electrical connection to the connecting member 12 between the solar cells C _{11 (the} first solar cell) and the solar cell C _{21 (second} solar cells) .

Although not shown, the solar cell C ₁₁ and the solar cell C ₂₁ are photoelectric conversion units that generate photogenerated carriers by light incident from both surfaces of the first and second main surfaces, and the photoelectric conversion units And a plurality of narrow finger electrodes formed on the first and second main surfaces, respectively, and a collector electrode composed of a wide bus bar electrode.

  The collector electrode is an electrode that collects photogenerated carriers generated by the photoelectric conversion unit, and is formed in a comb shape, for example, by combining a finger electrode extending in the Y direction and a bus bar electrode extending in the X direction. . The finger electrode is an electrode for collecting photogenerated carriers generated by the photoelectric conversion unit, and is arranged over almost the entire light incident surface of the photoelectric conversion unit. The bus bar electrode is an electrode for collecting photogenerated carriers collected by a plurality of finger electrodes. The bus bar electrode has a line shape with a predetermined interval along the X direction so as to intersect all the finger electrodes. Formed. The finger electrode and the bus bar electrode are made of a conductive metal material obtained by firing, for example, silver paste. Further, the number of bus bar electrodes per solar battery cell is appropriately set in consideration of the size and resistance of the solar battery cell. In the embodiment of the present invention, a case where one solar battery cell includes two bus bar electrodes will be described, but the number of bus bar electrodes included in one solar battery cell may be three or more.

The connection member 12 is a wiring having the longitudinal direction in the Y direction, and the bus bar electrodes 21a and 21b of the solar battery cell C ₁₁ (first solar battery cell) and the solar battery cell C ₂₁ (second solar battery cell). disposed on the crosses solar cells _{C 11} and the bus bar electrode 21a of the solar cell _{C 21,} and 21b. The connecting member 12 is bonded to the bus bar electrodes 21a and 21b at the four intersecting portions La and Lb. That is, the four bus bar electrodes 21a and 21b extending in the X direction and the one connecting member 12 extending in the Y direction intersect at four intersecting portions La and Lb and are electrically connected to each other. Each of the bus bar electrodes 21a and 21b and the connection member 12 is, for example, a wiring obtained by tin plating the surface of a copper foil. In FIG. 2, the finger electrodes are omitted.

With reference to FIG. 3, the cross-sectional structure of the solar cell module containing a filler, a surface protection material, and a back surface protection material is demonstrated. 3 is a cross-sectional view taken along the line AA in FIG. On the solar cells _{C 11} and the solar cell _{C 21,} bus bar electrodes 21a, 21b are disposed respectively. Connecting member 12 is provided with a solar cell _{C 11} and the bus bar electrode 21a of the solar cell _{C 21,} disposed on the 21b, are adhered bus bar electrode 21a, the 21b. Cushioning material 13a~13e is inserted between the main surface of the connecting member 12 and the solar cell _{C 11} and the solar cell _{C 21.} Thereby, the pressure concentration to the intersection parts La and Lb between the connecting member 12 and the bus bar electrodes 21a and 21b is suppressed. Further, the principal surface of the connecting member 12 and the solar cell _{C 11} and the solar cell _{C 21} is directly contact is suppressed by inserting a cushioning material 13 a to 13 e. Therefore, cell cracking in the laminating process can be suppressed, and the productivity and yield of the solar cell module can be improved. A metal foil may be bonded onto the bus bar electrodes 21a and 21b.

Cushioning material 13a~13e is adhered to the main surface of the connecting member 12 and the solar cell _{C 11, C 21.} When the interface between the connection member and the solar battery cell is not bonded, the gas from the member stays at the interface due to this. The appearance of the solar cell module is impaired due to gas retention (exterior appearance defect). Therefore, the interface between the connection member 12 and the solar cells C ₁₁ , C ₂₁ is brought into an adhesive state by bonding the buffer materials 13 a to 13 e to the main surfaces of the connection member 12 and the solar cells C ₁₁ , C _21. Therefore, it is possible to suppress the outgas from the member from staying at the interface. Therefore, the appearance defect of the solar cell module due to gas retention can be suppressed. In addition, the connection between the bus bar electrodes 21a and 21b and the connection member 12 can be kept good for a long time.

In the example of FIG. 3, the buffer materials 13 a to 13 e are embedded without a gap between the connection member 12 and the main surfaces of the solar cells C ₁₁ and C ₂₁ . Accordingly, connecting member 12 and the bus bar electrodes 21a, 21b and the intersection La, it is possible to further suppress the direct contact of the stress concentration and connection to Lb member 12 and the solar cell _{C 11, C 21.} Further, by a gap with no embedded cushioning material 13a~13e it is bonded to the entire between the main surface of the connecting member 12 and the solar cell C _11, C _21, that outgas from members at the interface to reside Further suppression can be achieved.

In the example of FIG. 3, since two bus bar electrodes are formed on each of the solar cells C ₁₁ , C ₂₁ , the gap between the solar cells C ₁₁ , C ₂₁ and the connection member 12 is in the region 5. It divides | segments and the buffer materials 13a-13e are inserted in the 5 area | region, respectively. The planar shapes of the five cushioning materials 13a to 13e are substantially equal to the shapes of the five regions excluding the intersecting portions La and Lb of the connecting member 12 in FIG. Thus, only between the connecting member 12 and the solar cell _{C 11, C 21,} by placing a cushioning material 13 a to 13 e, the material cost of the cushioning material 13 a to 13 e can be reduced. Note that the planar shape of the cushioning material is not limited to the case shown here, and may be other shapes as shown in FIGS. 4 and 5.

Solar cell C ₁₁ , solar cell C ₂₁ , bus bar electrodes 21 a and 21 b, connection member 12 and buffer materials 13 a to 13 e are embedded in filler 22, and surface protective material 24 and back surface protective material are filled by filler 22. 23 is bonded.

As materials of the buffer materials 13a to 13e and the filler 22, for example, thermoplastic resins such as ethylene vinyl acetate copolymer (EVA), silicone resin, polyvinyl chloride, polyvinyl butyral (PVB), polyurethane, and the like can be used. Since the thermoplastic resin is easily molded softens when heated, by using a thermoplastic resin as a buffer material 13 a to 13 e, connecting the cushioning material 13 a to 13 e in a simple manner member 12 and the solar cell _C 11, C It can be inserted between ₂₁ main surfaces. Moreover, since EVA is excellent in adhesiveness with glass or a resin film, the adhesiveness with the surface protective material 24 and the back surface protective material 23 is improved by using it as the filler 22.

  The surface protective material 24 is made of a light transmissive material such as a glass substrate or a light transmissive plastic. The back surface protective material 23 may be made of, for example, a film such as polyethylene terephthalate (PET), or a material having a three-layer structure of PET / aluminum foil / PET.

  (A) A method for manufacturing a solar cell module will be described. First, solar cells are produced by a well-known method, and a predetermined number of solar cells are electrically connected in series by tab wirings 11a and 11b to produce a string. A plurality of strings are electrically connected in series using the connecting member 12.

  (B) Next, on the surface protective material 24 made of a light transmissive material such as a glass substrate or a light transmissive plastic, the surface side filling material 22 made of sheet-like EVA, the tab wirings 11a and 11b, and the connection member 12, a plurality of solar battery cells electrically connected in series, a back surface side filler 22 made of sheet-like EVA, and a back surface protective material 23 made of a film such as PET are laminated in order.

  (C) Then, a laminating process is performed. Specifically, the laminate is placed in a decompression vessel, the decompression vessel is evacuated, and then temporarily crimped by thermocompression bonding at 150 ° C. for 10 minutes. Then, the filler 22 and the buffer materials 13a to 13e are completely cross-linked by heating at 150 ° C. for 1 hour. The solar cell module is completed through the above steps. Then, you may attach a terminal box and a metal frame as needed.

As described above, the present invention has been described by one embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.
(First modification)
In the example of FIG. 3, the case where the cushioning members 13 a to 13 e are divided into five regions excluding the intersecting portions La and Lb of the connecting member 12 in FIG. 2 has been described. The buffer materials 13a to 13e may be combined as shown in FIG. FIG. 4 is a plan view showing a state in which the connection member 12 is excluded from the configuration on the back surface side of the solar cells C ₁₁ and C ₂₁ located at one end of the first and second solar cell groups G ₁ and G ₂ . is there. The connecting member 12 is disposed in the area indicated by the dotted line. Cushioning member 15, connecting member 12 and the bus bar electrodes 21a, 21b and the intersection La, except Lb, it is inserted between the main surface of the connecting member 12 and the solar cell _{C 11} and the solar cell _{C 21,} connected In a region where the member 12 is not arranged, they are connected to each other to form an integral body. Thereby, handling of the buffer material 15 becomes easy, and production efficiency and throughput improve.

In the example of FIG. 4, the buffer material 15 is inserted only in a part between the connection member 12 and the main surfaces of the solar cells C ₁₁ and C ₂₁ , and the buffer material 15 is not inserted in the remaining part. The bus bar electrodes 21a and 21b and the buffer material 15 are arranged with a predetermined gap in the Y direction. This will reduce the accuracy of alignment between the solar cells C _11, C ₂₁ and the buffer material 15, thereby improving the productivity and yield of the solar cell module.
(Second modification)
The example of FIG. 5 differs from FIG. 4 in that the cushioning material 14 is embedded without a gap between the connecting member 12 and the main surfaces of the solar cells C ₁₁ and C ₂₁ . Therefore, the bus bar electrodes 21a and 21b and the buffer material 15 are disposed adjacent to each other in the Y direction. Other configurations are the same as those in FIG. Thus, as in the embodiment, the connecting member 12 and the bus bar electrodes 21a, 21b and the intersection La, further suppressed direct contact stress concentration and connection to Lb member 12 and the solar cell _{C 11, C 21} can do.

4 and 5, it is desirable that the buffer materials 14 and 15 are bonded to the main surfaces of the connection member 12 and the solar cells C ₁₁ and C ₂₁ . Appearance defects of the solar cell module due to gas retention can be suppressed.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

FIG. 1 is a plan view showing a configuration of a light receiving surface side of a solar cell module according to an embodiment of the present invention. FIG. 2 is an enlarged plan view showing the configuration of the back side of the solar cells C ₁₁ and C ₂₁ located at one end of the first and second solar cell groups G ₁ and G ₂ . FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2 and is a view for explaining a cross-sectional configuration of a solar cell module including a filler, a surface protective material, and a back surface protective material. FIG. 4 shows the configuration of the back surface side of the solar cells C ₁₁ , C ₂₁ located at one end of the first and second solar cell groups G ₁ , G ₂ in the first modification, excluding the connection member 12. FIG. FIG. 5 shows the configuration of the back surface side of the solar cells C ₁₁ and C ₂₁ located at one end of the first and second solar cell groups G ₁ and G ₂ in the second modification, excluding the connection member 12. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11a, 11b ... Tab wiring 12 ... Connection member 13a-13e, 14, 15 ... Buffer material 21a, 21b ... Bus-bar electrode 22 ... Filler material 23 ... Back surface protection material 24 ... Surface protection material C ... Solar cell G ... Solar cell group La, Lb ... intersections T1, T2 ... output terminals

Claims (4)

A first solar cell in which a bus bar electrode having a first direction as a longitudinal direction is disposed on the main surface;
A second solar cell adjacent to the first solar cell and a second direction substantially orthogonal to the first direction intersecting the bus bar electrode on the main surface of the first solar cell. A connection member that electrically connects the cell;
A solar cell module comprising: a cushioning material inserted into at least a portion between the connection member and a main surface of the first solar cell.   The solar cell module according to claim 1, wherein the buffer material is bonded to main surfaces of the connection member and the first solar cell.   The solar cell module according to claim 1 or 2, wherein the buffer material is embedded between the connecting member and the main surface of the first solar cell without a gap.   The solar cell module according to claim 1, wherein the buffer material is made of a thermoplastic resin.

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