JPWO2018235315A1 - Solar cell and solar cell module - Google Patents

Abstract

a semiconductor substrate having a pn junction; a light receiving surface bus electrode (12B) provided extending in the first direction on the light receiving surface side of the semiconductor substrate; and a back surface side facing the opposite side of the light receiving surface of the semiconductor substrate A plurality of back surface connection electrodes provided in a distributed manner along one direction. The light-receiving surface bus electrode (12B) has a plurality of through holes (60) penetrating in the thickness direction of the light-receiving surface bus electrode along the first direction. It arrange | positions in the position which opposes the area | region except the several through-hole (60), and the thickness direction of a semiconductor substrate.

Description

  The present invention relates to a solar battery cell constituting a solar battery module by being connected with a lead wire, and a solar battery module using the solar battery cell.

  When modularizing solar cells, lead wires made of rectangular copper wires are joined to each solar cell by soldering in order to connect a plurality of solar cells in series and take out the electrical output. The The lead wire usually shrinks when cooled from the high temperature state immediately after soldering to room temperature. And the solar cell after soldering of a lead wire generate | occur | produces curvature by shrinkage | contraction of a lead wire. The warpage of the solar battery cell causes damage to the solar battery cell.

  A grid electrode for extracting electricity generated in the solar battery cell and a bus electrode for collecting electricity from all the grid electrodes are disposed on the light receiving surface and the back surface of the solar battery cell. The grid electrode is being thinned and increased in number in order to improve the power generation area of the solar battery cell. On the other hand, the bus electrode is difficult to be thinned because of the relationship between securing the adhesive strength between the solar battery cell and the lead wire and the placement accuracy. Furthermore, the heat treatment during the formation of the grid electrode and the bus electrode causes damage to the power generation layer and lowers the power generation efficiency of the solar battery cell, so that the area of the electrode material is reduced as much as possible in combination with the use of expensive silver. There is a need.

  In Patent Document 1, the electrode paste is screen-printed so that the bus bar portion formed on the main surface of the semiconductor substrate partially has a slit portion in which a plurality of slits are arranged along the longitudinal direction of the bus bar portion. Printing by law is disclosed. According to the technique of Patent Document 1, the area of the bus bar electrode can be reduced while maintaining good adhesive strength between the bus bar electrode and the lead wire. It has not been solved.

  On the other hand, for the back surface of the solar battery cell, a bus electrode is required for joining to the back surface lead wire as well as the light receiving surface, but the bus electrode arranged in a straight line requires a large amount of electrode material, Arrangement of island-shaped junction electrodes instead of linear shapes has been studied.

Japanese Patent No. 4284368

  However, in recent years, the thickness of silicon substrates used for solar cells has been decreasing year by year and is expected to continue to decrease in the future. In the manufacturing process of the solar cell module, warpage due to the difference in thermal expansion coefficient between the lead wire and the solar battery cell is generated, and thus it is necessary to reduce warpage in the module manufacturing process. The occurrence of this warpage becomes more prominent as the silicon substrate becomes thinner.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the photovoltaic cell which can suppress the curvature of the photovoltaic cell resulting from joining of the lead wire to a photovoltaic cell.

  In order to solve the above-described problems and achieve the object, the present invention provides a semiconductor substrate having a pn junction, and a light-receiving surface bus electrode provided extending in the first direction on the light-receiving surface side of the semiconductor substrate. And a plurality of back surface connection electrodes provided in a distributed manner along the first direction on the back surface side facing away from the light receiving surface of the semiconductor substrate. The light-receiving surface bus electrode has a plurality of through holes penetrating in the thickness direction of the light-receiving surface bus electrode along the first direction, and the back surface connection electrode has a region excluding the plurality of through-holes in the light-receiving surface bus electrode. It arrange | positions in the position which opposes in the thickness direction of a semiconductor substrate.

  The solar cell concerning this invention has an effect that the curvature of the photovoltaic cell resulting from joining of the lead wire to a photovoltaic cell can be suppressed.

The perspective view which looked at the solar cell module concerning Embodiment 1 of this invention from the light-receiving surface side. The exploded perspective view which looked at the solar cell module concerning Embodiment 1 of this invention from the light-receiving surface side. Sectional drawing of the principal part of the solar cell module concerning Embodiment 1 of this invention. The perspective view which looked at the solar cell array concerning Embodiment 1 of this invention from the back surface side The perspective view which looked at the solar cell string concerning Embodiment 1 of this invention from the light-receiving surface side The perspective view which looked at the solar cell string concerning Embodiment 1 of this invention from the back surface side The top view which looked at the photovoltaic cell concerning Embodiment 1 of this invention from the light-receiving surface side The top view which looked at the photovoltaic cell concerning Embodiment 1 of this invention from the back surface side which faced the opposite side to the light-receiving surface side. It is sectional drawing which shows the structure of the photovoltaic cell concerning Embodiment 1 of this invention, and is principal part sectional drawing in the IX-IX line in FIG. It is sectional drawing which shows the structure of the photovoltaic cell concerning Embodiment 1 of this invention, and is principal part sectional drawing in the XX line in FIG. The top view which shows the shape of the light-receiving surface bus electrode of the photovoltaic cell concerning Embodiment 1 of this invention. The top view which shows the state which soldered the lead wire on the light-receiving surface bus electrode of the photovoltaic cell concerning Embodiment 1 of this invention. It is sectional drawing which shows the structure of the photovoltaic cell concerning Embodiment 1 of this invention, and is principal part sectional drawing in the XIII-XIII line | wire in FIG. It is sectional drawing which shows the structure of the photovoltaic cell concerning Embodiment 1 of this invention, and is principal part sectional drawing in the XIV-XIV line | wire in FIG. The flowchart explaining the procedure of the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. Sectional drawing which shows the principal part which shows the manufacturing process of the photovoltaic cell concerning Embodiment 1 of this invention. The flowchart which shows the procedure of the manufacturing method of the solar cell module concerning Embodiment 1 of this invention. The top view which looked at the photovoltaic cell concerning Embodiment 2 of this invention from the light-receiving surface side The top view which looked at the photovoltaic cell concerning Embodiment 2 of this invention from the back surface side which faced the opposite side to the light-receiving surface side. Sectional drawing which shows the structure of the solar cell module concerning Embodiment 2 of this invention. The figure which shows the structural conditions of the light-receiving surface electrode of the photovoltaic cell concerning Embodiment 2 of this invention. The figure which shows the structure conditions of the back surface connection electrode of the photovoltaic cell concerning Embodiment 2 of this invention. Sectional drawing which shows the structure of the photovoltaic cell concerning Embodiment 3 of this invention. The figure which shows the structural conditions of the light-receiving surface electrode of the photovoltaic cell concerning Embodiment 3 of this invention. The figure which shows the structure conditions of the back surface connection electrode of the photovoltaic cell concerning Embodiment 3 of this invention.

  Below, the photovoltaic cell and solar cell module concerning embodiment of this invention are 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 100 according to Embodiment 1 of the present invention as viewed from the light receiving surface side. FIG. 2 is an exploded perspective view of the solar cell module 100 according to the first embodiment of the present invention as viewed from the light receiving surface side. FIG. 3 is a cross-sectional view of main parts of the solar cell module 100 according to the first embodiment of the present invention. As shown in FIGS. 1 to 3, in the solar cell module 100 according to the first embodiment, the light receiving surface side of the solar cell array 70 is covered with the light receiving surface side sealing material 33 and the light receiving surface protection unit 31. The back surface side facing the light receiving surface in the array 70 is covered with the back surface side sealing material 34 and the back surface protection portion 32, and the periphery of the outer peripheral edge portion is surrounded by a reinforcing frame 40.

  FIG. 4 is a perspective view of the solar cell array 70 according to the first embodiment of the present invention as viewed from the back side. FIG. 5 is a perspective view of the solar cell string 50 according to the first embodiment of the present invention viewed from the light receiving surface side. FIG. 6: is the perspective view which looked at the solar cell string 50 concerning Embodiment 1 of this invention from the back surface side.

  As shown in FIG. 4, the solar cell array 70 is configured by a plurality of solar cell strings 50 being electrically and mechanically joined in series or in parallel by lateral lead wires 25 and output lead wires 26.

  Further, as shown in FIGS. 3 to 6, the solar cell string 50 includes a plurality of solar cells 10 each having a quadrangular shape arranged adjacent to each other, electrically and mechanically connected to each other in series by lead wires 20. Has been configured. As shown in FIGS. 3 to 6, the plurality of solar cells 10 are connected in series in the X direction in the drawing, which is the first direction, by lead wires 20. The first direction is a connection direction of the plurality of solar cells 10 connected by the lead wire 20.

  In the solar cell string 50, an electrode formed on the light receiving surface side which is the first main surface of one of the two adjacent solar cells 10 and the two adjacent solar cells 10. The electrodes formed on the back surface side, which is the second main surface of the other solar battery cell 10, are alternately connected by lead wires 20. The lead wire 20 is solder-bonded at one end to a back surface connection electrode 13B formed on the back surface side of the solar cell 10 to be described later, and the light receiving surface bus electrode 12B formed on the light receiving surface side of the adjacent solar cell 10. The other end side is solder-joined. That is, the lead wire 20 connected to the light receiving surface bus electrode 12 </ b> B formed on the light receiving surface side of the solar battery cell 10 is connected to the back surface connection electrode 13 </ b> B formed on the back surface side of the adjacent solar battery cell 10. A plurality of solar cells 10 are connected in series.

  FIG. 7 is a plan view of the solar battery cell 10 according to the first embodiment of the present invention as viewed from the light receiving surface side. FIG. 8: is the top view which looked at the photovoltaic cell 10 concerning Embodiment 1 of this invention from the back surface side which faces the opposite side to the light-receiving surface side. FIG. 9 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view of the main part along the line IX-IX in FIG. FIG. 10 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view taken along line XX in FIG. 9 and 10, the lead wire 20 connected to the solar battery cell 10 is also shown.

  The solar cell 10 includes a semiconductor substrate 11 having a rectangular shape in which an impurity diffusion layer is formed and a pn junction is formed. That is, in the solar cell 10, n is an impurity diffusion layer in which n-type impurities are diffused by phosphorus diffusion on the light-receiving surface side of the semiconductor substrate 1 made of p-type silicon which is the first conductivity type. A type impurity diffusion layer 2 is formed. The n-type impurity diffusion layer 2 is formed on the light receiving surface 11 </ b> A side of the semiconductor substrate 11. The outer shape of the semiconductor substrate 11 has a square shape, that is, a rectangular shape in the surface direction of the semiconductor substrate 11.

  In the solar cell 10, a concavo-convex shape is formed on the light receiving surface 11 </ b> A side of the semiconductor substrate, which is the first main surface of the semiconductor substrate 11, by texture etching in order to increase the light collection rate. That is, minute irregularities are formed as a texture structure on the surface of the semiconductor substrate 11. The minute unevenness increases the area of the light receiving surface 11A that absorbs light from the outside, suppresses the reflectance at the light receiving surface 11A, and has a structure for confining light. In FIG. 9 and FIG. 10, the illustration of minute irregularities is omitted for convenience. Further, in the solar cell 10, the antireflection film 3 made of a silicon nitride film is formed on the light receiving surface 11 </ b> A side of the semiconductor substrate that is the first main surface of the semiconductor substrate 11.

  As the semiconductor substrate 1, a p-type single crystal silicon substrate or a p-type polycrystalline silicon substrate can be used. The semiconductor substrate 1 is not limited to this, and an n-type single crystal silicon substrate, an n-type polycrystalline silicon substrate, or another silicon-based substrate may be used. The antireflection film 3 may be a silicon oxide film.

  In the solar cell 10, a light receiving surface electrode 12 is formed on the light receiving surface 11 </ b> A side of the semiconductor substrate, and a back electrode 13 is formed on the back surface 11 </ b> B side of the semiconductor substrate that is the second main surface of the semiconductor substrate 11.

  On the light receiving surface side of the semiconductor substrate 1, the above-described light receiving surface electrode 12 is provided so as to penetrate the antireflection film 3 and be electrically connected to the n-type impurity diffusion layer 2. As the light receiving surface electrode 12, a plurality of elongated light receiving surface grid electrodes 12G are provided side by side in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11. The light receiving surface grid electrode 12 </ b> G is an electrode for collecting the photocurrent generated by the solar battery cell 10 from the light receiving surface 11 </ b> A side of the semiconductor substrate 11. The light-receiving surface grid electrode 12G is electrically connected to the n-type impurity diffusion layer 2 at the bottom surface portion. The light receiving surface grid electrode 12G is a paste electrode formed by applying and baking a conductive paste having metal particles in a desired range.

  In addition, a light receiving surface bus electrode 12B that is electrically connected to the light receiving surface grid electrode 12G is provided orthogonal to the light receiving surface grid electrode 12G in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11. As shown in FIG. 7, the light-receiving surface bus electrodes 12 </ b> B are provided in four lines in a line over almost the entire length of the solar cells 10 along the first direction that is the connecting direction of the solar cells 10. . That is, the longitudinal direction of the light-receiving surface bus electrode 12 </ b> B is the same direction as the first direction described above, and is a connection direction of the plurality of solar cells 10 connected by the lead wires 20. The light receiving surface bus electrode 12B is arranged in the same direction as the second direction orthogonal to the first direction in the surface of the semiconductor substrate 11. The light receiving surface bus electrode 12B is connected to all the light receiving surface grid electrodes 12G. The light-receiving surface bus electrode 12B is electrically connected to the n-type impurity diffusion layer 2 at the bottom surface portion. For convenience, FIGS. 1, 2, 4 and 5 show a case where the light receiving surface bus electrodes 12B are provided in two rows.

  The light-receiving surface bus electrode 12B is an electrode provided for collecting the photocurrent collected by the light-receiving surface grid electrode 12G and electrically joining the lead wire 20. The light-receiving surface bus electrode 12B is a paste electrode formed by applying and baking a conductive paste having metal particles in a desired range. When the solar cell module 100 is manufactured using the solar cells 10, the lead wires 20 are soldered to the light receiving surface bus electrodes 12 </ b> B as shown in FIGS. 9 and 10. 9 and 10, only the light receiving surface bus electrode 12B of the light receiving surface electrode 12 is shown.

  FIG. 11 is a plan view showing the shape of the light-receiving surface bus electrode 12B of the solar battery cell 10 according to the first embodiment of the present invention. As shown in FIGS. 7 and 11, a plurality of through holes 60 penetrating the light receiving surface bus electrode 12B in the thickness direction are provided in the light receiving surface bus electrode 12B in the in-plane direction of the solar battery cell 10, that is, the semiconductor substrate. 11 is provided in a stepping stone shape along the first direction in the in-plane direction. FIG. 7 shows a case where seven through holes 60 are provided in the light-receiving surface bus electrode 12B along the first direction as an example.

  That is, the light-receiving surface bus electrode 12B includes a plurality of first regions 61 in which the through holes 60 are not provided and a plurality of second regions 62 in which the through holes 60 are provided in the first direction. The plurality of first regions 61 and the plurality of second regions 62 are alternately provided in the extending direction of the light-receiving surface bus electrode 12B, that is, in the first direction. In the second region 62, adjacent first regions 61 in the extending direction of the light-receiving surface bus electrode 12B are connected to each other by a connection portion 63 provided in the outer edge region in the width direction of the light-receiving surface bus electrode 12B. Accordingly, all the first regions 61 and the second regions 62 in one light-receiving surface bus electrode 12B are electrically connected.

  Further, the soldering of the lead wire 20 to the light receiving surface bus electrode 12B is mainly performed by soldering the first region 61 and the lead wire 20. Therefore, the soldering area between the light receiving surface bus electrode 12 </ b> B and the lead wire 20 is approximated to the soldering area between the first region 61 and the lead wire 20.

  By providing the plurality of through holes 60 in the light-receiving surface bus electrode 12B, the amount of electrode material used for the light-receiving surface bus electrode 12B can be reduced, and the manufacturing cost of the solar battery cell 10 can be reduced.

  Further, the size and position of the through hole 60 may be matched with the size and position of the back surface connection electrode 13B described later. The dimension and position of the back connection electrode 13B are determined in consideration of the characteristics of the solar battery cell 10.

  Further, an increase in the electrical resistance of the light receiving surface bus electrode 12B due to the provision of the through hole 60 in the light receiving surface bus electrode 12B can be suppressed by increasing the height of the light receiving surface bus electrode 12B.

  As shown in FIG. 11, the light-receiving surface bus electrode 12B has the same width in the longitudinal direction, the width in the first region 61 is equal to the width in the second region 62, and both ends in the second direction. The part is a straight line parallel to the first direction. The second direction corresponds to the Y direction in FIG. Then, when manufacturing the solar cell module 100 by connecting the lead wire 20 to the electrode of the solar battery cell 10, the lead wire 20 having the same width as the light receiving surface bus electrode 12B is positioned at the position in the second direction. The light-receiving surface bus electrode 12B is soldered to the light-receiving surface bus electrode 12B in a state of being overlapped with the bus electrode 12B.

  FIG. 12 is a plan view showing a state where the lead wire 20 is soldered onto the light-receiving surface bus electrode 12B of the solar battery cell 10 according to the first embodiment of the present invention. FIG. 13 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view taken along line XIII-XIII in FIG. FIG. 14 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a main-portion cross-sectional view taken along line XIV-XIV in FIG.

  As shown in FIGS. 13 and 14, the lead wire 20 is overlapped on the light receiving surface bus electrode 12B in a position parallel to the light receiving surface bus electrode 12B and overlapping the light receiving surface bus electrode 12B in the width direction of the lead wire 20. And soldered to the upper surface of the light-receiving surface bus electrode 12B. That is, the lead wire 20 is soldered to the light-receiving surface bus electrode 12B in a state where the side surface 20b in the width direction of the lead wire overlaps the side surface 12Ba of the light-receiving surface bus electrode in the width direction in the second direction. The longitudinal direction of the lead wire 20 soldered to the light-receiving surface bus electrode 12B is the same direction as the longitudinal direction of the light-receiving surface bus electrode 12B, and is the same direction as the first direction described above, that is, the X direction. The width direction of the lead wire 20 soldered to the light-receiving surface bus electrode 12B is the same direction as the width of the light-receiving surface bus electrode 12B, and is the same direction as the second direction described above, that is, the Y direction.

  As shown in FIG. 12, the lead wire 20 has the same width in the longitudinal direction, and has the same width as the width of the light-receiving surface bus electrode 12B. Therefore, as shown in FIG. 13, in the plurality of second regions 62 provided with the through holes 60, the width of the lead wire 20 is the width of the second region 62, that is, two connections facing each other in the second direction. This is the same dimension as the length between the outer side surfaces 63a of the part. The outer side surface 63a of the connection portion corresponds to the side surface 12Ba of the light receiving surface bus electrode in the second region 62. As shown in FIG. 14, in the plurality of first regions 61 where the through hole 60 is not provided, the width of the lead wire 20 is the width of the first region 61, that is, the length of the first region 61 in the second direction. Same dimensions.

  Soldering of the lead wire 20 to the light-receiving surface bus electrode 12B in the plurality of second regions 62 provided with the through-holes 60 leads to the connection portion 63 provided in the outer edge region in the width direction of the light-receiving surface bus electrode 12B. The soldering with the wire 20 is performed at both ends in the width direction of the lead wire 20.

  The width of the light receiving surface bus electrode 12B is 0.6 mm or more and 1.2 mm or less. The width of the light receiving surface grid electrode 12G is 30 μm or more and 80 μm or less. The width of the connection part 63 is 60 μm or more and 160 μm or less. The width of the connecting portion 63 is about 1/15 or more and 1/5 or less of the width of the light receiving surface bus electrode 12B. When the width of the light-receiving surface bus electrode 12B is within the above range, the amount of electrode material used for the light-receiving surface bus electrode 12B is reduced, and the electrical property of the light-receiving surface bus electrode 12B due to the provision of the through hole 60 Considering the increase in resistance, the width of the connecting portion 63 is most preferably about 1/10 of the width of the light receiving surface bus electrode 12B.

  Further, when the width of the light receiving surface grid electrode 12G is in the above range, the width of the connecting portion 63 is about twice as large as the width of the light receiving surface grid electrode 12G. In consideration of the reduction in the amount of electrode material used for the light-receiving surface bus electrode 12B and the increase in the electrical resistance of the light-receiving surface bus electrode 12B due to the provision of the through holes 60, the width of the connecting portion 63 is the light receiving Although it depends on the height of the surface bus electrode 12B, a width of about twice the width of the light receiving surface grid electrode 12G is most preferable.

  When the width of the light receiving surface grid electrode 12G is thinned, if the number of the light receiving surface grid electrodes 12G is increased by the thinning of the width of the light receiving surface grid electrode 12G, the amount of received light and the electrode resistance loss are the same. Since the distance through which the carriers flow through the n-type impurity diffusion layer 2 before reaching the light-receiving surface grid electrode 12G is shortened, the resistance loss in the n-type impurity diffusion layer 2 is reduced. For this reason, the thinning of the width of the light receiving surface grid electrode 12G is preferable from the viewpoint of resistance loss. However, the lower limit width is selected as the width of the light receiving surface grid electrode 12G due to manufacturing limitations. In particular, when the light receiving surface grid electrode 12G is formed by inexpensive screen printing, the lower limit width of the light receiving surface grid electrode 12G that can be formed in thinning is 30 μm or more and 100 μm or less.

  The width of the connecting portion 63 is also preferably made thin from the viewpoint of reducing the amount of electrode material used. However, the lower limit width is selected from the manufacturing limitations and the solar cell 10 characteristics. The light receiving surface grid electrode 12G and the connecting portion 63 are simultaneously printed by screen printing using a single print mask together with the light receiving surface bus electrode 12B. Accordingly, the height of the light receiving surface grid electrode 12G, the height of the connection portion 63, and the height of the light receiving surface bus electrode 12B printed by screen printing are approximately the same. When the height of the light receiving surface grid electrode 12G and the height of the connection portion 63 are the same height, the connection portion 63 has several, ie, two, three, five, and six light receiving surface grid electrodes 12G. Therefore, the width of the connecting portion 63 is preferably about twice that of the light receiving surface grid electrode 12G.

  As described above, both ends of the light-receiving surface bus electrode 12B in the second direction are linearly parallel to the first direction. That is, in the light receiving surface bus electrode 12B, the outer side surface 63a of the two connecting portions facing each other in the second direction is a straight line parallel to the first direction. When the solar cell module 100 is manufactured by connecting the lead wire 20 to the electrode of the solar battery cell 10, the light-receiving surface bus electrode 12B has a side surface of the light-receiving surface bus electrode in the width direction in the second direction. The lead wire 20 is soldered in a state where the side surface 20b in the width direction of the lead wire overlaps 12Ba. That is, the position of the side surface 12Ba of the light receiving surface bus electrode and the position of the side surface 20b in the width direction of the lead wire are the same in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11.

  Therefore, in a state where the lead wire 20 is soldered to the light receiving surface bus electrode 12 </ b> B, the connection portion 63 does not protrude outward from the first region 61. That is, in a state where the lead wire 20 is soldered to the light receiving surface bus electrode 12B, the connection portion 63 is included in the lead wire 20 in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11.

  For this reason, the solar cell 10 is caused by the presence of the connecting portion 63 in a state of protruding from the lead wire 20 without being soldered to the lower surface of the lead wire 20 in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11. Thus, a decrease in the amount of received light of the solar battery cell 10 can be prevented. That is, the light receiving surface bus electrode 12B protruding from the lead wire 20 prevents an unnecessary shadow from being formed on the light receiving surface 11A of the semiconductor substrate 11, thereby preventing a decrease in photoelectric conversion efficiency.

  For example, when the connection portion 63 is provided so as to protrude outward from the first region 61 in the second direction, the connection portion 63 extends from the lead wire 20 connected to the light receiving surface bus electrode 12B. As a result, the amount of received light of the solar battery cell 10 is reduced, which causes a decrease in photoelectric conversion efficiency.

  Further, since both end portions in the second direction of the light-receiving surface bus electrode 12B are formed in a straight line parallel to the first direction, the connection portion 63 connects the first regions 61 adjacent in the first direction. The semiconductor substrate 11 is connected with the shortest distance in the in-plane direction. For this reason, it is possible to suppress the resistance loss in the second region 62 caused by the photocurrent collected in the light-receiving surface bus electrode 12 </ b> B flowing through the connection portion 63 having a narrower width than the first region 61.

  In addition, when the light receiving surface grid electrode 12G and the lead wire 20 are soldered, stress at the time of soldering concentrates on the light receiving surface grid electrode 12G and the light receiving surface grid electrode 12G may be disconnected. In the solar cell 10, the connection portion 63 is soldered to the lead wire 20 in the second region 62, and the light receiving surface grid electrode 12 </ b> G and the lead wire 20 are not soldered. For this reason, the photovoltaic cell 10 can suppress disconnection of the light receiving surface grid electrode 12G due to soldering between the light receiving surface grid electrode 12G and the lead wire 20.

  Further, when the solar battery cell 10 is manufactured by connecting the lead wire 20 to the electrode of the solar battery cell 10 and manufacturing the solar battery module 100, the general lead wire 20 having the same width in the longitudinal direction can be used. Thus, the lead wire 20 having a shape exclusively for the solar battery cell 10 is not necessary.

  The solar cell module 100 uses a general lead wire 20 having the same width in the longitudinal direction. Thereby, when the lead wire 20 is soldered to the solar battery cell 10, the positioning of the solar battery cell 10 and the lead wire 20 in the longitudinal direction of the light receiving surface bus electrode 12B and the lead wire 20, that is, the light receiving surface bus electrode. Positioning of 12B and the lead wire 20 becomes unnecessary. Therefore, the solar cell module 100 can be easily manufactured because the light-receiving surface bus electrode 12B and the lead wire 20 can be soldered at an arbitrary position in the longitudinal direction between the light-receiving surface bus electrode 12B and the lead wire 20.

  On the other hand, on the back surface 11B side of the semiconductor substrate, as shown in FIGS. 6 and 8, a back surface collecting electrode 13A containing aluminum (Al) and a plurality of dot-like back surface connecting electrodes 13B containing silver (Ag) are formed. The back electrode 13 is configured. In addition, a region around the surface of the back surface of the semiconductor substrate 1 that is in contact with the back surface collecting electrode 13A is a back surface electric field layer for improving the open-circuit voltage and the short-circuit current. A back surface field (BSF) layer 4 which is a p + region diffused at a high concentration is formed on the surface layer on the side.

  The back surface collecting electrode 13 </ b> A is an electrode provided for forming the BSF layer 4 and collecting the photocurrent generated in the solar cell 10 from the back surface 11 </ b> B side of the semiconductor substrate 11. Cover almost the whole area. The back surface collecting electrode 13A is a paste electrode formed by applying a conductive paste having Al metal particles as an electrode material to a desired range and baking it.

  The back connection electrode 13B is an electrode provided for taking out the photocurrent collected by the back surface collection electrode 13A to the outside and making contact with the external electrode. That is, the back surface connection electrode 13 </ b> B is an electrode provided for joining with the lead wire 20. Similar to the light receiving surface bus electrode 12B, the back surface connection electrode 13B is provided along a first direction that is a connecting direction of the solar cells 10. The back connection electrode 13B is a paste electrode formed by applying a conductive paste having Ag metal particles as an electrode material to a desired range and baking it.

  The back connection electrode 13B is disposed at a position facing the light receiving surface bus electrode 12B with the semiconductor substrate 11 in between. Further, as shown in FIG. 8, the back surface connection electrodes 13 </ b> B are dispersed and arranged in a stepping stone shape over almost the entire length of the solar battery cells 10 along the first direction that is the connection direction of the solar battery cells 10. It is provided in a row. By forming the back connection electrode 13B in a stepping stone shape, the amount of silver used can be suppressed and the manufacturing cost can be suppressed.

  9 and 10, the position of the back surface connection electrode 13B is the position of the through hole 60 in the light receiving surface bus electrode 12B in the in-plane direction of the solar battery cell 10, that is, the in-plane direction of the semiconductor substrate 11. The position does not match. In other words, the first region 61 of the light-receiving surface bus electrode 12 </ b> B and the back surface connection electrode 13 </ b> B are arranged at opposing positions in the thickness direction of the semiconductor substrate 11 with the semiconductor substrate 11 interposed therebetween. Therefore, the first region 61 of the light-receiving surface bus electrode 12B and the back surface connection electrode 13B are arranged at corresponding positions in the surface of the semiconductor substrate 11.

  Therefore, in one solar cell 10, the lead wire 20 soldered to the light receiving surface bus electrode 12B on the light receiving surface side and the lead wire 20 connected to the back surface connecting electrode 13B on the back surface side In the in-plane direction of the semiconductor substrate 11, that is, in the in-plane direction of the semiconductor substrate 11, is soldered to the solar battery cell 10 at the same position. That is, in one solar battery cell 10, the lead wire 20 soldered to the light receiving surface side of the solar battery cell 10 and the lead wire 20 soldered to the back surface side of the solar battery cell 10 Soldering is performed at an opposite position in the thickness direction.

  Then, the area of the first region 61 of the light receiving surface bus electrode 12B and the area of the back surface connection electrode 13B in the in-plane direction of the solar battery cell 10 are substantially the same, so that the light receiving surface bus electrode 12B and the lead wire 20 are the same. And the soldering area of the back connection electrode 13B and the lead wire 20 are substantially equal.

  Thereby, in the photovoltaic cell 10 concerning this Embodiment 1, when the lead wire 20 is soldered to the photovoltaic cell 10 in order to form the several photovoltaic cell 10, the lead wire 20 and the light-receiving surface bus | bath Most of the internal stress generated in the connection portion between the electrode 12B and the connection portion between the lead wire 20 and the back surface connection electrode 13B can be offset.

  When the solar cell module 100 is manufactured by connecting the lead wire 20 to the electrode of the solar battery cell 10, the lead wire 20 is soldered to the light receiving surface bus electrode 12B and the back surface connection electrode 13B as shown in FIGS. Attached. When the light-receiving surface bus electrode 12B does not have the through holes 60 and the back surface connection electrodes 13B are dispersed and arranged in a stepping stone shape, the area of the light-receiving surface bus electrode 12B in the surface of the semiconductor substrate 11 and the semiconductor The difference from the area of the back connection electrode 13B in the plane of the substrate 11 becomes large. For this reason, the internal stress which arises in the connection part of the lead wire 20 and the light-receiving surface bus electrode 12B which originates in the soldering of the lead wire 20 at the time of preparation of the solar cell module 100, and the lead wire 20 and the back surface connection electrode 13B. The difference between the internal stress and the internal stress generated in the connection portion increases. In this case, internal stress generated in the connection portion between the lead wire 20 and the light-receiving surface bus electrode 12B on the light-receiving surface side of the solar battery cell 10, and connection between the lead wire 20 and the back-surface connection electrode 13B on the back surface side of the solar battery cell 10. The internal stress generated in the portion cannot be balanced, and the difference in the internal stress causes the warpage of the solar battery cell 10.

  As a result, warpage due to a difference in thermal expansion coefficient between the lead wire 20 made of metal and the silicon of the semiconductor substrate 11 occurs. In general, the thermal expansion coefficient of the metal constituting the lead wire 20 is larger than that of silicon. Therefore, when the light receiving surface bus electrode 12B does not have the through holes 60 and the back surface connection electrodes 13B are dispersed and arranged in a stepping stone shape, that is, the area of the light receiving surface bus electrode 12B in the surface of the semiconductor substrate 11 is the semiconductor. When the area of the back surface connection electrode 13B in the plane of the substrate 11 is larger than the area of the back surface connection electrode 13B, the solar cell 10 is warped convexly on the back surface side after soldering.

  On the other hand, in the solar cell 10, the first region 61 of the light-receiving surface bus electrode 12 </ b> B and the back surface connection electrode 13 </ b> B are arranged at corresponding positions in the surface of the semiconductor substrate 11, and the in-plane direction of the solar cell 10. The area of the first region 61 of the light receiving surface bus electrode 12B and the area of the back surface connection electrode 13B are substantially the same so that the soldering area between the light receiving surface bus electrode 12B and the lead wire 20 and the back surface connection The soldering area between the electrode 13B and the lead wire 20 becomes substantially equal. Thereby, the fixing position of the light-receiving surface bus electrode 12B and the lead wire 20 by soldering and the fixing position of the back surface connection electrode 13B and the lead wire 20 by soldering become the same position in the surface of the semiconductor substrate 11, In the solar cell 10, the above-described internal stress can be balanced on the light receiving surface side and the back surface side of the solar cell 10. For this reason, the photovoltaic cell 10 can suppress the curvature of the photovoltaic cell 10 resulting from soldering of the lead wire 20 to the photovoltaic cell 10 at the time of production of the photovoltaic cell module 100. Therefore, the solar cell 10 can reduce the damage rate of the solar cell 10 due to the warp of the solar cell 10 when the solar cell module 100 is manufactured.

  And in the in-plane direction of the photovoltaic cell 10, the area of the 1st area | region 61 of the light-receiving surface bus electrode 12B and the area of the back surface connection electrode 13B are made into the exact same area, The light-receiving surface of the photovoltaic cell 10 The balance of the internal stress described above on the side and the back side can be accurately taken.

  Moreover, in the photovoltaic cell 10, since the curvature of the photovoltaic cell 10 at the time of preparation of the photovoltaic module 100 can be suppressed as described above, it is possible to cope with the thinning of the semiconductor substrate 11, and a thinner semiconductor. It is possible to reduce the cost of the semiconductor substrate 11 using the substrate 11 and to realize an inexpensive solar battery cell 10.

  In addition, the structure of the photovoltaic cell 10 concerning this Embodiment 1 mentioned above is an example, and is not limited to said description about the structure of a bulk type photovoltaic cell.

  7 and 8 show a case where the number of the light receiving surface bus electrodes 12B and the back surface connecting electrodes 13B is four as a representative example, the number of the light receiving surface bus electrodes 12B and the back surface connecting electrodes 13B is as described above. It is not limited to description.

  Next, a method for manufacturing the solar battery cell 10 according to the first embodiment will be described with reference to FIGS. 15 to 22. FIG. 15 is a flowchart for explaining the procedure of the manufacturing process of the solar battery cell 10 according to the first embodiment of the present invention. FIGS. 16-22 is principal part sectional drawing which shows the manufacturing process of the photovoltaic cell 10 concerning Embodiment 1 of this invention. 20 to 22 show diagrams corresponding to FIG.

  First, as the semiconductor substrate 1, as shown in FIG. 16, for example, a square p-type single crystal silicon substrate that is most frequently used for consumer solar cells is prepared. Here, the thickness and dimensions of the semiconductor substrate 1 are not particularly limited. As an example, the thickness of the semiconductor substrate 1 is 200 μm, and the outer dimension in the surface direction of the semiconductor substrate 1 is 156 mm × 156 mm.

  Since the semiconductor substrate 1 is manufactured by slicing a silicon ingot formed by cooling and solidifying molten silicon with a wire saw, damage at the time of slicing remains on the surface. Therefore, first, the semiconductor substrate 1 is immersed in an acid solution or a heated alkaline solution to etch the surface while also removing the damaged layer, and is generated when the semiconductor substrate 1 is cut out and close to the surface of the semiconductor substrate 1. Remove existing damage areas. An example of the alkaline solution is an aqueous sodium hydroxide solution.

  Next, in step S <b> 10, minute unevenness (not shown) is formed as a texture structure on the light receiving surface side surface of the semiconductor substrate 1. The minute irregularities are formed, for example, by immersing the semiconductor substrate 1 in a mixed solution of sodium hydroxide and isopropyl alcohol, which is an alkaline aqueous solution, and performing wet etching of the semiconductor substrate 1.

  Next, in step S20, the semiconductor substrate 1 having fine textures formed on the surface as a texture structure is put into a thermal diffusion furnace and heated in an atmosphere of phosphorus (P) which is an n-type impurity to A pn junction is formed on the entire surface. Through this process, phosphorus is diffused from the surface of the semiconductor substrate 1 to the semiconductor substrate 1 to form an n-type impurity diffusion layer 2 on the surface layer of the semiconductor substrate 1 as shown in FIG. Thereby, the semiconductor substrate 11 having a pn junction is obtained.

The n-type impurity diffusion layer 2 is formed, for example, by putting the semiconductor substrate 1 into a thermal diffusion furnace and in a mixed atmosphere of phosphorus oxychloride (POCl ₃ ) gas and oxygen gas, for example, at a temperature of about 750 ° C. to 900 ° C. This is done by heating. The concentration of phosphorus diffused in the surface layer of the semiconductor substrate 1 can be controlled by conditions such as the concentration of phosphorus oxychloride gas, the ambient temperature, and the heating time. Here, on the surface after the formation of the n-type impurity diffusion layer 2, a phosphor glass layer (not shown), which is a hybrid of a silicon oxide film containing phosphorous oxide as a main component and phosphorous oxide, is formed. For this reason, the phosphorus glass layer on the surface of the n-type impurity diffusion layer 2 is removed using a chemical such as a hydrofluoric acid aqueous solution.

  Next, in step S30, a pn separation step for electrically insulating the back electrode 13 as a p-type electrode and the light-receiving surface electrode 12 as an n-type electrode is performed, and as shown in FIG. The end n-type impurity diffusion layer 2 is removed. Since the n-type impurity diffusion layer 2 is uniformly formed on the surface of the semiconductor substrate 1, the light receiving surface 11A and the back surface 11B of the semiconductor substrate 11 are in an electrically connected state. Therefore, when the back electrode 13 and the light receiving surface electrode 12 are formed on the semiconductor substrate 11, the back electrode 13 and the light receiving surface electrode 12 are electrically connected. In order to break this electrical connection, pn separation is performed. Examples of the pn separation include end face etching using plasma etching or melt separation using laser processing.

  Next, in step S40, on the light receiving surface side of the semiconductor substrate 11, that is, on the n-type impurity diffusion layer 2, for example, nitriding as an antireflection film 3 as shown in FIG. 19 for surface protection and photoelectric conversion efficiency improvement. A silicon (SiN) film is formed. The antireflection film 3 is formed by using, for example, a plasma-enhanced chemical vapor deposition (PECVD) method, and a silicon nitride film is formed as the antireflection film 3 using a mixed gas of silane and ammonia. To do. The film thickness and refractive index of the antireflection film 3 are set to values that most suppress light reflection.

  Next, an electrode is formed. First, in step S50, the light receiving surface electrode 12 is printed on the light receiving surface side of the semiconductor substrate 11 by screen printing. That is, as shown in FIG. 20, a silver electrode paste 12a, which is an electrode material paste containing silver and glass frit, is printed in the shape of the light receiving surface electrode 12 on the antireflection film 3 on the light receiving surface side of the semiconductor substrate 11. The Here, the silver electrode paste 12a is printed in the shape of the light-receiving surface bus electrode 12B including the plurality of first regions 61 and the plurality of second regions 62 shown in FIGS. Thereafter, the silver electrode paste 12a is dried.

  Next, in step S60, the back electrode 13 is printed on the back surface of the semiconductor substrate 11 by screen printing. The printing of the back surface collecting electrode 13A and the printing of the back surface connecting electrode 13B do not cause any problem, but here, the case where the back surface connecting electrode 13B is printed first is shown.

  First, as shown in FIG. 21, a silver electrode paste 13b, which is an electrode material paste containing silver and glass frit, is printed on the back surface of the semiconductor substrate 11 in the shape of the back surface connection electrode 13B. The silver electrode paste 13b is a print mask having an opening pattern at a position corresponding to a position where the first region 61 of the light receiving surface bus electrode 12B is formed on the light receiving surface of the semiconductor substrate 11 in the back surface of the semiconductor substrate 11. Printed using. Thereafter, the silver electrode paste 13b is dried at a temperature of 200 ° C. for 5 minutes.

  Next, as shown in FIG. 21, an aluminum electrode paste 13a, which is an electrode material paste containing aluminum and glass frit, is printed on the back surface of the semiconductor substrate 11 in the shape of the back surface collecting electrode 13A. The aluminum electrode paste 13a is printed using a print mask having an opening pattern on the entire back surface of the back surface of the semiconductor substrate 11 except for a part of the print region of the back surface connection electrode 13B and an outer edge region. The aluminum electrode paste 13a is printed so that at least a part thereof is electrically connected to the silver electrode paste 13b. Thereafter, the aluminum electrode paste 13a is dried at a temperature of 200 ° C. for 5 minutes.

  Thereafter, in step S70, electrode firing is performed to perform a firing process on the printed paste. By firing the electrode paste printed on the semiconductor substrate 11, as shown in FIG. 22, the light receiving surface grid electrode 12G and the light receiving surface bus electrode 12B as the light receiving surface electrode 12, and the back surface collecting electrode 13A as the back electrode 13 And the back connection electrode 13B. Firing is performed at about 750 ° C. or more and 900 ° C. or less in an air atmosphere using an infrared heating furnace. The selection of the firing temperature is performed in consideration of the structure of the solar battery cell 10 and the type of electrode paste.

  By baking, on the light receiving surface side of the semiconductor substrate 11, the silver of the light receiving surface electrode 12 penetrates through the antireflection film 3 which is an insulating film through the fire, and the n-type impurity diffusion layer 2 and the light receiving surface electrode 12 are electrically connected. Connect to. Thereby, the n-type impurity diffusion layer 2 can obtain a good resistive junction with the light-receiving surface electrode 12.

  On the other hand, on the back surface side of the semiconductor substrate 11, the aluminum electrode paste 13a and the silver electrode paste 13b are baked to form the back surface collecting electrode 13A and the back surface connection electrode 13B, and are configured by aluminum and silver. The alloy part which does not do is formed.

  When the back surface collecting electrode 13A is formed, the aluminum electrode paste 13a also reacts with the p-type single crystal silicon on the back surface of the semiconductor substrate 11 and solidifies after the reaction, whereby the BSF layer 4 which is a p + layer containing aluminum. Is formed. That is, in the n-type impurity diffusion layer 2 formed on the back surface 11B side of the semiconductor substrate 11, the region immediately below the back surface collecting electrode 13A is changed to the BSF layer 4 by the diffusion of aluminum. Further, in the n-type impurity diffusion layer 2 formed on the back surface side of the semiconductor substrate 11, the region other than the region immediately below the back surface collecting electrode 13 </ b> A is diffused into a p-type region.

  Below, the method to manufacture the solar cell module 100 provided with the photovoltaic cell 10 concerning this Embodiment 1 is demonstrated. FIG. 23 is a flowchart showing the procedure of the method for manufacturing the solar cell module 100 according to the first embodiment of the present invention.

  First, in step S110, a plurality of solar cells are formed by soldering and joining the lead wires 20 to the light-receiving surface bus electrode 12B of one solar cell 10 and the back surface connection electrode 13B of the other solar cell 10. 10 are electrically connected by the lead wire 20, and the solar cell string 50 is formed.

  Next, in step S120, the sheet of the light receiving surface side sealing material 33, the solar cell string 50, the sheet of the back surface side sealing material 34, and the back surface protection portion 32 are sequentially stacked on the light receiving surface protection portion 31, and the laminate. Is formed.

  Next, in step S130, the laminate is mounted on a laminating apparatus, and heat treatment and laminating treatment are performed for about 30 minutes at a temperature of about 140 ° C. or higher and 160 ° C. or lower. Thereby, each member of a laminated body is integrated via the light-receiving surface side sealing material 33 and the back surface side sealing material 34, and the solar cell module 100 is obtained.

  Thereafter, the outer edge of the solar cell module 100 is held by the frame 40 over the entire circumference.

  As described above, in the solar battery cell 10 according to the first embodiment, the plurality of through holes 60 are provided in the light receiving surface bus electrode 12B. Thereby, in the photovoltaic cell 10, the usage-amount of the electrode material used for the light-receiving surface bus electrode 12B can be reduced, and the manufacturing cost of the photovoltaic cell 10 can be reduced.

  Further, in the solar cell 10 according to the first embodiment, the first region 61 of the light-receiving surface bus electrode 12B and the back surface connection electrode 13B are arranged at corresponding positions in the surface of the semiconductor substrate 11, and the semiconductor substrate 11 Through the semiconductor substrate 11 in the thickness direction. Thereby, the photovoltaic cell 10 can suppress the curvature of the photovoltaic cell 10 resulting from the soldering of the lead wire 20 to the photovoltaic cell 10 at the time of production of the photovoltaic cell module 100. It is possible to reduce the breakage rate of the solar battery cell 10 due to the warp of the solar battery cell 10 at the time of production.

  Moreover, in the photovoltaic cell 10 concerning this Embodiment 1, the light-receiving surface bus electrode 12B is made into the same width | variety over a longitudinal direction, and the both ends in a 2nd direction are linear form parallel to a 1st direction. The width of the light receiving surface bus electrode 12B is the same as the width of the lead wire 20 connected to the width of the light receiving surface bus electrode 12B and having the same width in the longitudinal direction. When the solar cell module 100 is manufactured, the position of the side surface 12Ba of the light receiving surface bus electrode on both sides of the light receiving surface bus electrode 12B in the second direction and the width direction of the lead wires on both sides of the lead wire 20 in the second direction. The position of the side surface 20 b of the semiconductor substrate 11 is the same position in the in-plane direction of the light receiving surface 11 A of the semiconductor substrate 11. The position of the side surface 12Ba of the light receiving surface bus electrode and the position of the side surface 20b in the width direction of the lead wire are the same in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11. Thereby, the solar cell 10 prevents a decrease in the amount of light received by the solar cell 10 due to the light-receiving surface bus electrode 12B protruding from the lead wire 20 in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. A decrease in photoelectric conversion efficiency can be prevented.

  Moreover, since the photovoltaic cell 10 can suppress the curvature of the photovoltaic cell 10 at the time of production of the photovoltaic module 100, the cost of the semiconductor substrate 11 is reduced by using a thinner semiconductor substrate 11, and the inexpensive photovoltaic cell 10. Can be realized.

  Therefore, according to the photovoltaic cell 10 concerning this Embodiment 1, there exists an effect that the curvature of the photovoltaic cell resulting from joining of the lead wire to a photovoltaic cell can be suppressed.

Embodiment 2. FIG.
FIG. 24 is a plan view of the solar battery cell 110 according to the second embodiment of the present invention as viewed from the light receiving surface side. FIG. 25: is the top view which looked at the photovoltaic cell 110 concerning Embodiment 2 of this invention from the back surface side which faces the light-receiving surface side and the opposite side. FIG. 26: is principal part sectional drawing which shows the structure of the solar cell module concerning Embodiment 2 of this invention. FIG. 26 is a diagram corresponding to FIG. 3, and is a cross-sectional view of a main part of the solar cell module according to the second embodiment configured by the solar cells 110. The cross-sectional view of the solar battery cell 110 in FIG. 26 is a main-portion cross-sectional view taken along the line XXIII-XXIII in FIG. FIG. 27 is a diagram illustrating the configuration conditions of the light-receiving surface electrode 112 of the solar battery cell 110 according to the second embodiment of the present invention. FIG. 28 is a diagram showing the configuration conditions of the back surface connection electrode 113B of the solar battery cell 110 according to the second embodiment of the present invention.

  The solar battery cell 110 according to the second exemplary embodiment includes a light receiving surface grid electrode 12G and a light receiving surface bus electrode 112B instead of the light receiving surface electrode 12 including the light receiving surface grid electrode 12G and the light receiving surface bus electrode 12B. A light receiving surface electrode 112 is provided. Further, the solar battery cell 110 includes a back surface electrode 113 composed of the back surface current collecting electrode 13A and the back surface connection electrode 113B instead of the back surface electrode 13 composed of the back surface current collecting electrode 13A and the back surface connection electrode 13B. . The solar battery cell 110 has the same configuration as that of the solar battery cell 10 according to the first embodiment except for the configuration of the light-receiving surface electrode 112 and the back electrode 113. In the solar cell 110, the same configuration as that of the solar cell 10 according to the first embodiment is denoted by the same reference numeral, and detailed description thereof is omitted.

  The light receiving surface bus electrode 112B is different in arrangement from the light receiving surface bus electrode 12B. The back connection electrode 113B is different in arrangement from the back connection electrode 13B.

  Four light-receiving surface bus electrodes 112 </ b> B are provided in the solar battery cell 110. In the solar cell 110, the semiconductor substrate 11 has a rectangular shape, and has a first end side portion and a second end side portion which are a pair of end portions parallel to each other. Here, the first end side portion is a side on one end 101 side which is one end portion of the solar battery cell 110 in the first direction. The second end side portion is the other end portion of the solar battery cell 110 in the first direction, which is parallel to the one end 101 and on the other end 102 side opposite to the one end 101 in the first direction. It is. In each light-receiving surface bus electrode 112B, the first region 611, the first region 612, the first region 613, and the first region 614 from the one end 101 side to the other end 102 side in the first direction in the first direction. , A first region 615, a first region 616, a first region 617, and a first region 618 are arranged.

  Here, the one end 101 side of the solar cell 110 in the first direction is an end portion side on the side where the adjacent solar cell 110 to which the light-receiving surface bus electrode 112B is connected by the lead wire 20 is arranged. 24 corresponds to the left side of the solar battery cell 110 in FIG. In the solar cell 110, the end portion on the side where the adjacent solar cell 110 to which the light-receiving surface bus electrode 112B is connected by the lead wire 20 is disposed is the end portion on the interconnection side on the light-receiving surface side.

  In addition, the other end 102 side of the solar cell 110 in the first direction is an end portion side on the side where the adjacent solar cell 110 to which the light receiving surface bus electrode 112B is connected by the lead wire 20 is not disposed, and FIG. 26 corresponds to the right side of the solar battery cell 110 in FIG. In the solar cell 110, the end on the side where the adjacent solar cell 110 to which the light receiving surface bus electrode 112B is connected by the lead wire 20 is not disposed is the end on the non-interconnect side on the light receiving surface side.

  The length of the first region in the longitudinal direction of the light-receiving surface bus electrode 112B, that is, the length of the first region in the first direction is the length of the first region 611, the first region length A1, the first region. The length of 612 is the first region length A2, the length of the first region 613 is the first region length A3, the length of the first region 614 is the first region length A4, and the length of the first region 615 is The first region length A5, the length of the first region 616 is the first region length A6, the length of the first region 617 is the first region length A7, and the length of the first region 618 is the first region length. A8.

  In the first direction, the distance from one end 101 of the solar battery cell 110 to the first region 611 is a distance B1, the distance between the first region 611 and the first region 612 is a distance B2, and the first region 612 is The distance between the first region 613 is a distance B3, the distance between the first region 613 and the first region 614 is a distance B4, the distance between the first region 614 and the first region 615 is a distance B5, The distance between the first region 615 and the first region 616 is a distance B6, the distance between the first region 616 and the first region 617 is a distance B7, and the distance between the first region 617 and the first region 618 is A distance from the first region 618 to the other end 102 of the solar battery cell 110 is a distance B9.

  Four back surface connection electrodes 113B are provided in the solar battery cell 110. The same number of back surface connection electrodes 113B as the number of the first regions 61 of the light receiving surface bus electrode 112B are provided at positions corresponding to the first regions 61 in the surface of the semiconductor substrate 11. In each back connection electrode 113B, the back connection electrode 1131, the back connection electrode 1132, the back connection electrode 1133, the back connection electrode 1134, from the one end 101 side to the other end 102 side of the solar battery 110 in the first direction, A back connection electrode 1135, a back connection electrode 1136, a back connection electrode 1137, and a back connection electrode 1138 are arranged.

  The back surface connection electrode 113 </ b> B is disposed at a position corresponding to the first region 61 within the surface of the semiconductor substrate 11. Therefore, in the plane of the semiconductor substrate 11, the back surface connection electrode 1131 is at a position corresponding to the first region 611, the back surface connection electrode 1132 is at a position corresponding to the first region 612, and the back surface connection electrode 1133 is at the first position. In the position corresponding to the region 613, the back surface connection electrode 1134 is in a position corresponding to the first region 614, the back surface connection electrode 1135 is in the position corresponding to the first region 615, and the back surface connection electrode 1136 is in the first region 616. The back connection electrode 1137 is disposed at a position corresponding to the first region 617, and the back connection electrode 1138 is disposed at a position corresponding to the first region 618.

  Here, the one end 101 side of the solar cell 110 in the first direction described above is an end side on the side where the adjacent solar cell 110 to which the back surface connection electrode 113B is connected by the lead wire 20 is not disposed. In the solar cell 110, the end on the side where the adjacent solar cell 110 to which the back connection electrode 113B is connected by the lead wire 20 is not disposed is the end on the non-interconnect side on the back side.

  Moreover, the other end 102 side of the solar battery cell 110 in the first direction is an end portion side on the side where the adjacent solar battery cell 110 to which the back surface connection electrode 113B is connected by the lead wire 20 is disposed. In the solar cell 110, the end on the side where the adjacent solar cell 110 to which the back connection electrode 113B is connected by the lead wire 20 is disposed is an end on the interconnect side on the back side.

  The length of the back surface connection electrode 113B in the first direction is such that the back surface connection electrode 1131 is the back surface connection electrode length C1, the back surface connection electrode 1132 is the back surface connection electrode length C2, and the back surface connection electrode 1133 is long. Is the back connection electrode length C3, the back connection electrode 1134 is the back connection electrode length C4, the back connection electrode 1135 is the back connection electrode length C5, and the back connection electrode 1136 is the back surface. The connection electrode length C6, the length of the back connection electrode 1137 is the back connection electrode length C7, and the length of the back connection electrode 1138 is the back connection electrode length C8.

  In the first direction, the distance from one end 101 of the solar battery cell 110 to the back surface connection electrode 1131 is a distance D1, the distance between the back surface connection electrode 1131 and the back surface connection electrode 1132 is a distance D2, and the back surface connection electrode 1132 is The distance between the back surface connection electrode 1133 is a distance D3, the distance between the back surface connection electrode 1133 and the back surface connection electrode 1134 is a distance D4, the distance between the back surface connection electrode 1134 and the back surface connection electrode 1135 is a distance D5, and the back surface The distance between the connection electrode 1135 and the back connection electrode 1136 is a distance D6, the distance between the back connection electrode 1136 and the back connection electrode 1137 is a distance D7, and the distance between the back connection electrode 1137 and the back connection electrode 1138 is The distance D8 and the distance from the back connection electrode 1138 to the other end 102 of the solar battery cell 110 are the distance D9.

  The semiconductor substrate 11 has, for example, a 156 mm square shape. The first region length A1, the first region length A2, the first region length A3, the first region length A4, the first region length A5, the first region length A6 and the first region length A7 are: For example, 5 mm. The first region length A8 is longer than the first region length A1 to the first region length A7, for example, 11 mm. The distance B1 and the distance B9 are, for example, 0.5 mm. The distance B2 and the distance B8 are, for example, 7 mm. The distance B3, the distance B4, the distance B5, the distance B6, and the distance B7 are, for example, 19 mm.

  Back connection electrode length C1, back connection electrode length C2, back connection electrode length C3, back connection electrode length C4, back connection electrode length C5, back connection electrode length C6, back connection electrode length C7 and back The connection electrode length C8 is, for example, 5 mm. The distance D9 is longer than the distance D1, and there is a relationship of distance D1 <distance D9. For example, the distance D1 = 0.5 mm and the distance D9 = 6.5 mm. The distance D2 and the distance D8 are 7 mm, for example. The distance D3, the distance D4, the distance D5, the distance D6, and the distance D7 are, for example, 19 mm.

  On the light receiving surface side of the solar battery cell 110, it is preferable to provide the light receiving surface bus electrode 112B up to both ends of the solar battery cell 110 in the first direction. On the other hand, on the back surface side of the solar battery cell 110, particularly on the other end 102 side that is the lead wire connection side, the distance from the end surface of the solar battery cell 110 to the back surface connection electrode 113B can be increased in the first direction. preferable.

  The light receiving surface side of the solar battery cell 110 is a convex curved surface. That is, since the back surface collecting electrode 13A using an electrode material containing aluminum is formed on the entire back surface of the solar battery cell 110, warpage due to the difference in thermal expansion coefficient between aluminum and silicon occurs in the solar battery cell 110. To do. In general, since the thermal expansion coefficient of aluminum is larger than the thermal expansion coefficient of silicon, the solar battery cell 110 is warped to protrude toward the light receiving surface after the heat treatment for firing the electrodes.

  When the lead wire 20 is soldered to the solar battery cell 110, the light receiving surface is convex, and therefore, between the solar battery cell 110 and the lead wire 20, it is perpendicular to the light receiving surface of the solar battery cell 110. The stress which peels the lead wire 20 occurs. And the stress which peels becomes the largest in the edge part of the photovoltaic cell 110. FIG.

  Therefore, on the light receiving surface side of the solar battery cell 110, the light receiving surface bus electrode 112B on the end side of the solar battery cell 110 and the lead wire are provided by providing the light receiving surface bus electrode 112B to both ends of the semiconductor substrate 11 in the first direction. The joint strength between 20 and 20 can be increased. That is, as described above, the light-receiving surface grid electrode 12G is formed up to a position where the distance B1 and the distance B9 are 0.5 mm in the first direction. Then, the light receiving surface bus electrodes 112B are provided up to the light receiving surface grid electrodes 12G at both ends in the first direction, and the light receiving surface bus electrodes 112B are provided up to the positions at both ends of the semiconductor substrate 11 in the first direction. Thereby, the photovoltaic cell 110 can further increase the bonding strength between the light receiving surface bus electrode 112B and the lead wire 20 on the end side. Further, since both ends of the light-receiving surface bus electrode 112B in the first direction are configured by the first region, the bonding strength between the light-receiving surface bus electrode 112B and the lead wire 20 on the end side can be increased. . When both ends of the light-receiving surface bus electrode 112B in the first direction are configured by the second region 62, the end portion of the light-receiving surface bus electrode 112B is soldered to the lead wire 20 only by the connection portion 63. Bond strength decreases.

  Moreover, in the solar cell 110, the semiconductor substrate 11 has a first end side that is an end of the solar cell 110 in the first direction and a solar cell on the opposite side to the first end side in the first direction. A rectangular shape having a second end side which is an end of the cell 110; Then, the distance between the back connection electrode 113B adjacent to the second end side and the second end side is made longer than the distance between the back connection electrode 113B adjacent to the first end side and the first end side. ing.

  The solar battery cell 10 according to the first embodiment described above has a symmetric configuration in the first direction with respect to the center position in the first direction. Therefore, when the photovoltaic cells 10 are connected to each other by the lead wires 20, as shown in FIG. 3, the lead wire 20 is arranged from the lower left to the upper right in the drawing, and the adjacent photovoltaic cells 10 are connected to each other. 3 is equivalent to the configuration in which the lead wires 20 are arranged from the upper left to the lower right and the adjacent solar cells 10 are connected to each other with respect to the adjacent solar cells 10 shown in FIG.

  On the other hand, the solar battery cell 110 according to the second embodiment has an asymmetric configuration in the first direction with respect to the center position in the first direction. Therefore, when the photovoltaic cells 110 are connected to each other by the lead wires 20, as shown in FIG. 26, the lead wires 20 are arranged from the lower left to the upper right in the drawing, and the adjacent solar cells 110 are connected to each other. 26, the lead wires 20 are arranged from the upper left to the lower right, and the adjacent solar cells 110 are not equivalent to the configuration of connecting the adjacent solar cells 110 to each other.

  Here, the configuration in which the lead wires 20 are arranged from the lower left to the upper right and connect the adjacent solar cells 10 to each other is the left solar cell among the solar cells 10 arranged on the left and right as shown in FIG. The back surface connection electrode 13 </ b> B of the cell 10 and the light receiving surface bus electrode 12 </ b> B of the right solar cell 10 are connected by a lead wire 20. In addition, the configuration in which the lead wire 20 is arranged from the upper left to the lower right and connects the adjacent solar cells 10 is the light receiving surface bus of the left solar cell 10 among the solar cells 10 arranged on the left and right. In this configuration, the electrode 12 </ b> B and the back surface connection electrode 13 </ b> B of the right solar cell 10 are connected by the lead wire 20.

  On the back surface side of the solar battery cell 110 having the above-described configuration, the back surface connection from the end face of the solar battery cell 110 is performed on the other end 102 side of the solar battery cell 110 that is the end portion of the solar battery cell 110 on the back side. Increasing the distance to the electrode 113B, that is, the distance D9 from the back connection electrode 1138 to the other end 102 of the solar battery cell 110 has the following effects.

  As shown in FIG. 26, the solar cell module according to Embodiment 2 is configured such that a plurality of solar cells 110 are connected by lead wires 20 and the other solar cell 110b is connected from the back side of one solar cell 110a. The lead wire 20 is connected in a curved shape to the light receiving surface side. That is, the solar cell module according to Embodiment 2 includes the second end side portion of one solar cell 110 disposed on the left side in FIG. 26 and the other solar cell disposed on the right side in FIG. It arrange | positions in the state which the 1st edge part of the cell 110 opposed, and the one photovoltaic cell 110 and the other photovoltaic cell 110 are adjacent in a 1st direction. In addition, the solar cell module according to the second embodiment includes the lead wire 20 that connects the back surface connection electrode 113B of one solar cell 110 and the light receiving surface bus electrode 112B of the other solar cell 110. Then, the lead wire 20 connects the back surface connection electrode 113B on the second end side in one solar cell 110 and the light receiving surface bus electrode 112B on the first end side in the other solar cell 110. To do.

  The length of the bending portion 20a that bends the lead wire 20 in a curved shape by setting the distance D1 <distance D9 and wiring the lead wire 20 from the back surface side of the solar cell 110a to the light receiving surface side of the adjacent solar cell 110b. Therefore, the bending radius of the bent portion 20a of the lead wire 20 is increased, and the stress concentration on the bent portion 20a of the lead wire 20 is reduced. In particular, the solar cell module is designed with a life expectancy of 10 years or longer. However, due to the difference in coefficient of linear expansion between the light receiving surface glass serving as the light receiving surface protection unit 31 and the lead wire 20, the temperature of day and night Due to the cycle, repeated stress is generated in the bent portion 20a of the lead wire 20 to cause disconnection, which causes failure. Here, by increasing the bending radius of the bent portion 20a of the lead wire 20, the repeated stress applied to the bent portion 20a can be reduced, so that a solar cell module excellent in long-term reliability can be realized.

  In the solar battery 110, the first region 61 other than the end portion on the non-interconnection side on the light receiving surface side, that is, the first region 61 other than the other end 102 side, and the back surface connection electrode 113B include the light receiving surface and the back surface. It is preferable to provide in the corresponding position. That is, the first region 611 to the first region 617 are preferably provided at positions corresponding to the back surface connection electrode 1131 to the back surface connection electrode 1137 in the plane of the solar battery cell 110, respectively. Thereby, except for the first region 618 and the back surface connection electrode 1138, the fixing position between the light receiving surface bus electrode 112B and the lead wire 20 and the fixing position between the back surface connection electrode 113B and the lead wire 20 by soldering are the semiconductor. The position is the same in the plane of the substrate 11. Thereby, the photovoltaic cell 110 suppresses the curvature of the photovoltaic cell 110 resulting from the soldering of the lead wire 20 to the photovoltaic cell 110 at the time of production of the photovoltaic module, similarly to the photovoltaic cell 10 described above. be able to. Therefore, the solar battery cell 110 can reduce the damage rate of the solar battery cell 110 due to the warp of the solar battery cell 110 when the solar battery module is manufactured.

  In the light-receiving surface bus electrode 112B, the interval between the first regions adjacent on the end portion side in the first direction includes the interval between the first regions adjacent in the central portion in the first direction. It is preferable that the distance is shorter than the interval between adjacent first regions on the inner side. That is, in the light-receiving surface bus electrode 112B, the length of the second region on the end side in the first direction is preferably shorter than the length of the second region on the inner side in the first direction. Therefore, (distance B2 = distance D2 = distance B8 = distance D8) <(distance B3 = distance D3, distance B4 = distance D4, distance B5 = distance D5, distance B6 = distance D6, distance B7 = distance D7). Is preferred.

  As described above, when the lead wire 20 is soldered to the solar cell 110, the solar cell 110 has a convex light-receiving surface side. Therefore, the solar cell 110 has a solar cell between the solar cell 110 and the lead wire 20. The stress at which the lead wire 20 is peeled in the direction perpendicular to the light receiving surface of the battery cell 110 is greatest on the end side in the first direction. On the other hand, by making the length of the second region on the end side in the first direction shorter than the length of the second region on the inner side in the first direction, the end portion side in the first direction The bonding strength between the light receiving surface bus electrode 112B and the lead wire 20 can be increased.

  As described above, in the solar battery cell 110 according to the second embodiment, except for the first region 618 and the back surface connection electrode 1138, the fixing position between the light receiving surface bus electrode 112B and the lead wire 20, and soldering The fixing position of the back connection electrode 113B and the lead wire 20 is the same position in the surface of the semiconductor substrate 11. Thereby, the photovoltaic cell 110 can reduce the damage rate of the photovoltaic cell 110 by the curvature of the photovoltaic cell 110 at the time of preparation of a photovoltaic module similarly to the photovoltaic cell 10 mentioned above.

  Moreover, in the photovoltaic cell 110 concerning this Embodiment 2, it is from the end surface of the photovoltaic cell 110 in the other end 102 side of the photovoltaic cell 110 which is the edge part of the interconnection side in the back surface side in the photovoltaic cell 110. The distance to the back connection electrode 113B is increased. Thereby, the length of the bending part 20a which bends the lead wire 20 which connects the adjacent photovoltaic cell 110 to curve shape becomes long. As a result, the stress concentration on the bent portion 20a of the lead wire 20 can be reduced, and due to the difference in coefficient of linear expansion between the light receiving surface glass serving as the light receiving surface protecting portion 31 and the lead wire 20, the daytime and nighttime can be reduced. Since the repeated stress applied to the bent portion 20a by the temperature cycle can be reduced, a solar cell module excellent in long-term reliability can be realized.

Embodiment 3 FIG.
FIG. 29 is a cross-sectional view showing the configuration of the solar battery cell 210 according to the third embodiment of the present invention. FIG. 29 is a cross-section along the longitudinal direction of the light-receiving surface electrode 212 that passes through the through hole 60, and illustration of the back surface collecting electrode 13A is omitted for easy understanding. FIG. 30 is a diagram illustrating the configuration conditions of the light-receiving surface electrode 212 of the solar battery cell 210 according to the third embodiment of the present invention. FIG. 31 is a diagram showing the configuration conditions of the back surface connection electrode 213B of the solar battery cell 210 according to the third embodiment of the present invention.

  The photovoltaic cell 210 according to the third embodiment includes a light receiving surface electrode 212 having a light receiving surface bus electrode 212B instead of the light receiving surface bus electrode 112B. Moreover, the solar cell 210 according to the third embodiment includes a back surface electrode 213 having a back surface connection electrode 213B instead of the back surface connection electrode 113B. Solar cell 210 has the same configuration as that of solar cell 110 according to the second embodiment except for the configuration of light-receiving surface electrode 212 and back electrode 213. In the solar cell 210, the same reference numerals are given to the same configurations as those of the solar cell 10 according to the first embodiment or the solar cell 110 according to the second embodiment, and detailed description thereof is omitted.

  The light receiving surface bus electrode 212B is different in arrangement from the light receiving surface bus electrode 112B. The rear surface connection electrode 213B is different in arrangement from the rear surface connection electrode 113B.

  The four light receiving surface bus electrodes 212B are provided in the solar battery cell 210 in the same manner as the light receiving surface bus electrode 112B. In each light-receiving surface bus electrode 212B, the first region 611, the first region 612, the first region 613, the first region 614, the first region 615, and the first region 616 are the same as the light-receiving surface bus electrode 112B. The first region 617 and the first region 618 are arranged along the first direction. Similarly to the back surface connection electrode 113B, the back surface connection electrodes 213B are distributed in 8 locations in a stepping stone shape over the substantially entire length of the solar cell 210 along the first direction, and are provided in 4 rows. .

  The same number of back surface connection electrodes 213B as the number of the first regions 61 of the light receiving surface bus electrode 212B are provided at positions corresponding to the first regions 61 in the surface of the semiconductor substrate 11.

  The first region 61 located on the light receiving surface bus electrode 212B other than the end side in the first direction, that is, located on the inner side in the first direction, and the back surface connection electrode 213B are the surfaces of the semiconductor substrate 11. When the semiconductor substrate 11 is seen through from a direction perpendicular to the inward direction, the center position in the first direction is the same position. That is, in the first direction, the center position of the first region 612 is the same position as the center position of the back surface connection electrode 1132. The center position of the first region 613 and the center position of the back surface connection electrode 1133, the center position of the first region 614 and the center position of the back surface connection electrode 1134, the center position of the first region 615 and the center position of the back surface connection electrode 1135 The same applies to the center position of the first region 616 and the back surface connection electrode 1136, and the center position of the first region 617 and the center position of the back surface connection electrode 1137.

  On the other hand, the first region 611 located on the end side in the first direction in the light-receiving surface bus electrode 212B and the back surface connection electrode 1131 are seen through the semiconductor substrate 11 from a direction perpendicular to the in-plane direction of the semiconductor substrate 11. In this case, the center position in the first direction is not the same position. That is, in the first direction, the center position of the first region 611 is different from the center position of the back surface connection electrode 1131. Similarly, in the first direction, the center position of the first region 618 is different from the center position of the back surface connection electrode 1138.

  The arrangement pitch of the two first regions 61 adjacent on the inner side in the first direction is the same arrangement pitch. In addition, the arrangement pitch of the two back connection electrodes 213B adjacent on the inner side in the first direction is the same arrangement pitch. The arrangement pitch of the two first regions 61 adjacent on the inner side in the first direction and the arrangement pitch of the two back surface connection electrodes 213B adjacent on the inner side in the first direction are the same arrangement pitch. . The arrangement pitch of the first regions 61 is a distance between the center positions of the first regions 61 in the first direction. The arrangement pitch of the back surface connection electrodes 213B is the distance between the center positions of the back surface connection electrodes 213B in the first direction.

  That is, the arrangement pitch between the first area 612 and the first area 613, the arrangement pitch between the first area 613 and the first area 614, the arrangement pitch between the first area 614 and the first area 615, and the first area 615 and the first area 615. An arrangement pitch between the first region 616, an arrangement pitch between the first region 616 and the first region 617, an arrangement pitch between the back surface connection electrode 1132 and the back surface connection electrode 1133, an arrangement pitch between the back surface connection electrode 1133 and the back surface connection electrode 1134, The arrangement pitch of the back connection electrode 1134 and the back connection electrode 1135, the arrangement pitch of the back connection electrode 1135 and the back connection electrode 1136, and the arrangement pitch of the back connection electrode 1136 and the back connection electrode 1137 are the same arrangement pitch.

  The first region length A2, the first region length A3, the first region length A4, the first region length A5, the first region length A6, and the first region length A7 are the same. The back surface connection electrode length C2, the back surface connection electrode length C3, the back surface connection electrode length C4, the back surface connection electrode length C5, the back surface connection electrode length C6, and the back surface connection electrode length C7 are the same. The first region length A2 is longer than the back surface connection electrode length C2.

  The distance B3, the distance B4, the distance B5, the distance B6, and the distance B7 are the same. The distance D3, the distance D4, the distance D5, the distance D6, and the distance D7 are the same. The distance D3 is longer than the distance B3.

  Therefore, (first area length A2 + distance B3) = (first area length A3 + distance B4) = (first area length A4 + distance B5) = (first area length A5 + distance B6) = (first area Length A6 + Distance B7) = (Back connection electrode length C2 + Distance D3) = (Back connection electrode length C3 + Distance D4) = (Back connection electrode length C4 + Distance D5) = (Back connection electrode length C5 + Distance D6) = (Back connection electrode length C6 + distance D7).

  In order to make the center position of the first region 612 in the first direction coincide with the center position of the back surface connection electrode 1132 in the first direction, the first region 612 from the one end 101 of the solar battery cell 210 in the first direction. The distance from the center position of the solar battery cell 210 to the center position of the back surface connection electrode 1132 is the same distance. That is, (distance B1 + first region length A1 + distance B2 + first region length A2 / 2) = (distance D1 + back surface connection electrode length C1 + distance D2 + back surface connection electrode length C2 / 2).

  In order to make the center position of the first region 617 in the first direction coincide with the center position of the back surface connection electrode 1137 in the first direction, the first region from the other end 102 of the solar cell 210 in the first direction. The distance to the center position of 617 and the distance from the other end 102 of the solar battery cell 210 to the center position of the back surface connection electrode 1137 are the same distance. That is, (distance B9 + first region length A8 + distance B8 + first region length A7 / 2) = (distance D9 + back surface connection electrode length C8 + distance D8 + back surface connection electrode length C7 / 2).

  The first region length A1 is longer than the back surface connection electrode length C1. When the semiconductor substrate 11 is seen through from a direction perpendicular to the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1131 overlaps the first region 611 inside the first region 611 in the first direction, that is, In the first direction, the back surface connection electrode 1131 is disposed at a position included in the first region 611.

  The first region length A8 is longer than the back surface connection electrode length C8. When the semiconductor substrate 11 is seen through from a direction perpendicular to the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1138 overlaps the first region 618 inside the first region 618 in the first direction, that is, In the first direction, the back connection electrode 1138 is disposed at a position included in the first region 618.

  The back connection electrode length C1 and the back connection electrode length C8 are the same as the back connection electrode length C2.

  In the first direction, the arrangement pitch of the two first regions 61 adjacent on the end side in the first direction is shorter than the arrangement pitch of the two first regions 61 adjacent on the inner side in the first direction. . That is, in the light-receiving surface bus electrode 212B, the interval between the two first regions 61 adjacent on the end side in the first direction is the interval between the two first regions 61 adjacent in the central portion in the first direction. Shorter than the interval between two adjacent first regions 61 on the inner side in the first direction. Therefore, the distance B2 and the distance B8 are shorter than the distance B3, the distance B4, the distance B5, the distance B6, and the distance B7.

  In the first direction, the arrangement pitch of the two back connection electrodes 213B adjacent on the end side in the first direction is shorter than the arrangement pitch of the two back connection electrodes 213B adjacent on the inner side in the first direction. . That is, in one row of back surface connection electrodes 213B, the interval between the two back surface connection electrodes 213B adjacent on the end portion side in the first direction is between the two back surface connection electrodes 213B adjacent in the center portion in the first direction. This is shorter than the interval between two adjacent back surface connection electrodes 213B on the inner side in the first direction. Therefore, the distance D2 and the distance D8 are shorter than the distance D3, the distance D4, the distance D5, the distance D6, and the distance D7.

  In the solar cell 210 according to the third embodiment, the total of the first region lengths of the light receiving surface bus electrode 212B in the first direction is the light receiving surface bus electrode 112B of the solar cell 110 according to the second embodiment. The length of the first region is significantly longer than the total of the first region lengths. That is, as shown in FIG. 30, the total first region length in the solar battery cell 210, that is, the total from the first region length A1 to the first region length A8 is 76 mm. On the other hand, as shown in FIG. 27, the total of the first region lengths in the light receiving surface bus electrode 112B of the solar battery cell 110 according to the second embodiment, that is, from the first region length A1 to the first region length A8. The total is 46 mm.

  Soldering of the lead wire 20 to the light receiving surface bus electrode 212B is mainly performed by soldering the first region 61 and the lead wire 20. Therefore, the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction is approximate to the total length of the first region. Therefore, the total length of the first region is considered to be the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction.

  In the solar cell 210 according to the third embodiment, the total length of the first regions of the light receiving surface bus electrode 212B in the first direction is the total length of the back surface connection electrode 213B in the first direction. Longer than. Therefore, in the solar cell 210 according to the third embodiment, the length of the connection region between the light-receiving surface bus electrode 212B and the lead wire 20 in the first direction is equal to that of the back surface connection electrode 213B and the lead in the first direction. It is longer than the length of the connection area with the line 20. That is, as shown in FIG. 31, the total from the back surface connection electrode length C1 to the back surface connection electrode length C8 is 48 mm. On the other hand, as shown in FIG. 30, the total of the first area length, that is, the total from the first area length A1 to the first area length A8 is 76 mm.

  In the solar cell 210, the back surface collecting electrode 13A using an electrode material containing aluminum is formed on the entire back surface of the solar cell 210. Therefore, after the heat treatment for firing the electrode, the solar cell 210 has a light receiving surface side. Convex warpage occurs. For this reason, on the light receiving surface side of the solar battery cell 210 that is a convex curved surface, a greater stress is applied between the electrode and the lead wire 20 than the back surface side of the solar battery cell 210.

  In the solar cell 210, the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction is longer than the length of the back surface connection electrode 213B in the first direction. In solar cell 210, the length of the connection region between light-receiving surface bus electrode 212B and lead wire 20 in the first direction is the light reception in the first direction in solar cell 110 according to the second embodiment. The length is longer than the length of the connection region between the surface bus electrode 112 </ b> B and the lead wire 20. Thereby, the photovoltaic cell 210 ensures the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction so that the light receiving surface bus electrode 212B and the lead wire in the first direction are long. The bonding strength with 20 can be increased, and the peeling of the lead wire 20 can be suppressed.

  On the other hand, the back surface connection electrode 213B, which is a silver paste electrode formed by applying and baking a silver paste using an electrode material containing silver, is in a state after the baking treatment, rather than the light receiving surface electrode 212 that is a silver paste electrode. The composition is rich in glass components. Most of the silver paste electrode is composed of silver and glass after the baking treatment. In the silver paste electrode, silver has a function of flowing current. In the silver paste electrode, the glass has a function of maintaining the bonding strength between the semiconductor substrate 11 and the electrode.

  Comparing the light receiving surface electrode 212 that is a silver paste electrode and the back surface connection electrode 213B that is a silver paste electrode, the light receiving surface electrode 212 has a ratio of silver in the electrode material of the back surface connection electrode 213B in order to reduce resistance at the electrode. Is higher than. In the light-receiving surface electrode 212, it is preferable to increase the ratio of silver in the electrode material as much as possible in order to reduce the resistance at the electrode. On the other hand, on the back surface side of the solar battery cell 210, the function of collecting current from the semiconductor substrate 11 is handled by the back surface collecting electrode 13A using an electrode material containing aluminum. For this reason, in the back surface connection electrode 213B, the bonding strength with the semiconductor substrate 11 can be increased by reducing the ratio of silver in the electrode material and increasing the ratio of the glass component in the electrode material.

  Therefore, the solar cell 210 has a ratio of the glass component in the electrode material in the back surface connection electrode 213B in the state after the firing process, rather than a ratio of the glass component in the electrode material in the light receiving surface electrode 212 in the state after the firing process. By making it high, it is possible to maintain the bonding strength between the semiconductor substrate 11 and the back surface connection electrode 213B at a high level at which the back surface connection electrode 213B does not peel off. Thereby, the solar battery 210 makes the total length of the back surface connection electrode 213B in the first direction shorter than the total length of the first region length of the light receiving surface bus electrode 212B in the first direction. In addition, the bonding strength between the semiconductor substrate 11 and the back surface connection electrode 213B can be maintained at a high level at which the back surface connection electrode 213B does not peel off.

  As described above, in the solar cell 210 according to the third embodiment, the first region 61 of the light receiving surface bus electrode 212B and the back surface connection electrode 213B are arranged at corresponding positions in the surface of the semiconductor substrate 11. ing. Thereby, the photovoltaic cell 210 can reduce the damage rate of the photovoltaic cell 210 by the curvature of the photovoltaic cell 210 at the time of manufacture of a photovoltaic module similarly to the photovoltaic cell 10 and the photovoltaic cell 210 mentioned above. Is possible.

  Moreover, in the photovoltaic cell 210 concerning this Embodiment 3, it is from the end surface of the photovoltaic cell 210 in the other end 102 side of the photovoltaic cell 210 which is the edge part of the interconnection side in the back surface side in the photovoltaic cell 210. The distance to the back connection electrode 213B is increased. Thereby, similarly to the solar battery cell 110 according to the second exemplary embodiment, the stress concentration on the bent portion 20a of the lead wire 20 can be reduced, and the light receiving surface glass and the lead wire 20 serving as the light receiving surface protection portion 31 can be reduced. Due to the difference in the linear expansion coefficient, etc., it is possible to reduce the repeated stress applied to the bent portion 20a due to the temperature cycle of day and night, so that a solar cell module having excellent long-term reliability can be realized.

  Further, in the solar cell 210 according to the third embodiment, the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction is equal to that of the back surface connection electrode 213B and the lead in the first direction. It is longer than the length of the connection area with the line 20. Thereby, the photovoltaic cell 210 ensures the length of the connection region between the light receiving surface bus electrode 212B and the lead wire 20 in the first direction so that the light receiving surface bus electrode 212B and the lead wire in the first direction are long. The bonding strength with 20 can be increased, and the peeling of the lead wire 20 can be suppressed.

  The configuration shown in the above embodiment shows an example of the contents of the present invention, and the technologies of the embodiment can be combined with each other, and can be combined with another known technology. It is also possible to omit or change a part of the configuration without departing from the gist of the present invention.

  1,11 Semiconductor substrate, 2 n-type impurity diffusion layer, 3 antireflection film, 4 BSF layer, 10,110,210 solar cell, 11A light receiving surface, 11B back surface, 12, 112, 212 light receiving surface electrode, 12B, 112B , 212B Light receiving surface bus electrode, 12Ba Light receiving surface bus electrode side surface, 12G Light receiving surface grid electrode, 12a, 13b Silver electrode paste, 13, 113, 213 Back electrode, 13A Back surface collecting electrode, 13B, 113B, 213B, 1131 1132, 1133, 1134, 1135, 1136, 1137, 1138 Back connection electrode, 13a Aluminum electrode paste, 20 lead wire, 20a bent portion, 20b Side surface in the width direction of the lead wire, 25 lateral lead wire, 26 output lead wire, 31 Light-receiving surface protection part, 32 Back surface protection part, 33 Light-receiving surface side sealing material, 4 Back side sealing material, 40 frame, 50 solar cell string, 60 through-hole, 61, 611, 612, 613, 614, 615, 616, 617, 618 first region, 62 second region, 63 connecting portion, 63a Side surface outside the connecting portion, 70 solar cell array, 100 solar cell module, 101 one end, 102 other end, A1, A2, A3, A4, A5, A6, A7, A8 first region length, B1, B2, B3 , B4, B5, B6, B7, B8, B9 Distance, C1, C2, C3, C4, C5, C6, C7, C8 Back connection electrode length, D1, D2, D3, D4, D5, D6, D7, D8 , D9 distance.

As described above, in the solar cell 210 according to the third embodiment, the first region 61 of the light receiving surface bus electrode 212B and the back surface connection electrode 213B are arranged at corresponding positions in the surface of the semiconductor substrate 11. ing. Thereby, the photovoltaic cell 210 can reduce the damage rate of the photovoltaic cell 210 by the curvature of the photovoltaic cell 210 at the time of manufacture of a photovoltaic module similarly to the photovoltaic cell 10 and the photovoltaic cell 110 which were mentioned above. Is possible.

Claims (10)

a semiconductor substrate having a pn junction;
A light-receiving surface bus electrode provided extending in the first direction on the light-receiving surface side of the semiconductor substrate;
A plurality of back surface connection electrodes provided in a distributed manner along the first direction on the back surface side facing the light receiving surface of the semiconductor substrate;
With
The light-receiving surface bus electrode is provided with a plurality of through-holes extending in the thickness direction of the light-receiving surface bus electrode along the first direction,
The back connection electrode is disposed at a position facing the region of the light receiving surface bus electrode excluding the plurality of through holes and in the thickness direction of the semiconductor substrate;
A solar cell characterized by. The light-receiving surface bus electrode has a linear shape in which both end portions in a second direction orthogonal to the first direction are parallel to the first direction in the plane of the semiconductor substrate;
The solar battery cell according to claim 1. The light-receiving surface bus electrode is
A plurality of first regions in which the through holes are not provided in the first direction;
A plurality of second regions provided with the through holes in the first direction;
With
The back surface connection electrode is disposed at a position facing the plurality of first regions in the thickness direction of the semiconductor substrate;
The solar battery cell according to claim 1, wherein: Both ends of the light-receiving surface bus electrode in the first direction are constituted by the first region,
The solar battery cell according to claim 3. The semiconductor substrate has a first end side that is an end of the solar cell in the first direction, and an end of the solar cell opposite to the first end in the first direction. A second end side that is a rectangular shape,
The distance between the back connection electrode adjacent to the second end side and the second end side is greater than the distance between the back connection electrode adjacent to the first end side and the first end side. For a long time,
The solar battery cell according to any one of claims 1 to 4, wherein: An interval between the first regions adjacent on the end side in the first direction is shorter than an interval between the first regions adjacent on the inner side in the first direction;
The solar battery cell according to any one of claims 3 to 5, wherein: In the first direction, the first region of the light-receiving surface bus electrode is longer than the back surface connection electrode arranged at a position facing in the thickness direction of the semiconductor substrate,
The solar cell according to any one of claims 3 to 6, wherein: A plurality of solar cells according to any one of claims 1 to 7;
In the two solar cells adjacent in the first direction, a lead wire that connects the light receiving surface bus electrode of one of the solar cells and the back surface connection electrode of the other solar cell,
A solar cell module comprising: 6. The two according to claim 5, wherein the second end side part of one solar battery cell and the first end side part of the other solar battery cell are arranged so as to face each other and are adjacent in the first direction. Solar cells,
A lead wire connecting the back surface connection electrode of the one solar cell and the light receiving surface bus electrode of the other solar cell;
With
The lead wire connects the back surface connection electrode on the second end side in one of the solar cells and the light receiving surface bus electrode on the first end side in the other solar cell. To do,
A solar cell module characterized by. The width of the light receiving surface bus electrode is equal to the width of the lead wire,
The lead wires are positioned on both sides of the light-receiving surface bus electrode in a second direction orthogonal to the first direction in the plane of the semiconductor substrate, and on both sides of the lead wire in the second direction. The position of the side surface is the same position and is overlapped and connected to the light receiving surface bus electrode;
The solar cell module according to claim 8 or 9.