JP2015053303A - Solar cell, solar cell module, and method for manufacturing solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell which is easily wired and has high productivity, and a solar cell module.SOLUTION: Owing to a semiconductor substrate; a second amorphous silicon layer formed by successively laminating an i-type amorphous silicon layer and a second-conductivity-type amorphous silicon layer on a part of the semiconductor substrate at a side opposite to a light-receiving surface of the semiconductor substrate; a second electrode formed on the second amorphous silicon layer; an insulation film formed on the second electrode; a first amorphous silicon layer formed by successively laminating the i-type amorphous silicon layer and a first-conductivity-type amorphous silicon layer over the insulation film from the semiconductor substrate at the side opposite to the light-receiving surface of the semiconductor substrate; a first electrode formed on the first amorphous silicon layer; and a solar cell, a shape of a rear surface electrode of the solar cell can be simplified and a shape of the wiring sheet for connecting solar batteries can be simplified, thereby productivity and reliability of the solar cell and the solar cell module can be improved and enhanced.

Description

  The present invention relates to a solar battery cell, a solar battery module, and a method for manufacturing a solar battery cell. About.

In recent years, development of clean energy has been desired from the viewpoint of the problem of depletion of energy resources or global environmental problems such as an increase in atmospheric CO ₂ . In particular, solar power generation using a solar cell module has been developed and put into practical use as a new energy source.

  In a solar battery cell constituting a solar battery module, a pn junction is formed by diffusing impurities having a conductivity type opposite to that of a silicon substrate on a light receiving surface of a single crystal or polycrystalline silicon substrate. 2. Description of the Related Art Conventionally, double-sided electrode type solar cells in which electrodes are respectively formed on a light receiving surface of a silicon substrate and a back surface on the opposite side have been mainly used.

  In recent years, development of so-called back electrode type solar cells in which both a p-type electrode and an n-type electrode are formed on the back surface of a silicon substrate has been promoted. There exists patent document 1 as a prior art document which disclosed the solar cell module provided with the back electrode type photovoltaic cell.

  FIG. 12 is an explanatory view showing a wiring sheet used in a conventional solar cell module. Fig.12 (a) is a top view which shows typically the state which looked at the example of the wiring sheet used for the solar cell module from the side in which the wiring was formed. FIG. 12B is a cross-sectional view schematically showing a state viewed from the direction of the arrow IB-IB ′ in FIG. The wiring sheet 50 includes an insulating base 51 and wiring 56 including an n-type wiring 52, a p-type wiring 53, and connection wirings 54 a and 54 b formed on one surface of the insulating base 51. It is configured.

  Each of the n-type wiring 52, the p-type wiring 53, and the connection wirings 54a and 54b has conductivity. Each of the n-type wiring 52 and the p-type wiring 53 has a plurality of rectangular portions having a longitudinal direction and formed at predetermined intervals. The rectangular portion of the n-type wiring 52 and the rectangular portion of the p-type wiring 53 are alternately arranged one by one at a predetermined interval in a direction orthogonal to the longitudinal direction of the rectangular portion.

  The connection wirings 54a and 54b extend in a direction orthogonal to the longitudinal direction of the rectangular portions of the n-type wiring 52 and the p-type wiring 53, and the rectangular portions of the n-type wiring 52 and the p-type wiring 53 are It is connected to the connection wiring 54a or 54b. The n-type wiring 52 and the p-type wiring 53 are each formed in a comb shape.

  Further, the adjacent n-type wiring 52 and p-type wiring 53 other than the n-type wiring 52a and the p-type wiring 53a located at the end of the wiring sheet 50 are electrically connected by the connection wiring 54a or 54b. Connected. 54b is provided outside the portion where the solar battery is placed, and has a function of changing the direction in which the solar battery cells are connected, and is called a bus bar. By passing through the bus bar, the direction in which the solar cells are connected can be changed without providing a special wiring pattern at the corner.

  As shown in FIG. 12B, in the wiring sheet 50, the n-type wiring 52 and the p-type wiring 53 are formed only on one surface of the insulating substrate 51.

  FIG. 13 is an explanatory view showing a conventional solar battery cell. Fig.13 (a) is sectional drawing which shows typically an example of the conventional back electrode type photovoltaic cell. An antireflection film 67 is formed on the surface of the silicon substrate 61 having a concavo-convex shape that serves as a light receiving surface of the back electrode type solar battery cell 60. A passivation film 66 is formed on the back surface of the silicon substrate 61 which is the back surface of the back electrode type solar battery cell 60.

  Further, an n-type impurity diffusion region 62 in which an n-type impurity such as phosphorus is diffused and a p-type impurity diffusion region 63 in which a p-type impurity such as boron is diffused are formed on the back side inside the silicon substrate 61. ing.

  In the silicon substrate 61 having n-type or p-type conductivity, a plurality of pn junctions are formed at the interface between the n-type impurity diffusion region 62 or the p-type impurity diffusion region 63 and the silicon substrate 61. Accordingly, each of the n-type electrode 64 connected to the n-type impurity diffusion region 62 and the p-type electrode 65 connected to the p-type impurity diffusion region 63 is formed on the back side inside the silicon substrate 61. In addition, the electrodes respectively correspond to a plurality of pn junctions.

  FIG.13 (b) is the figure which looked at the back surface electrode type photovoltaic cell of Fig.13 (a) from the back surface. As shown in FIG. 13B, the n-type electrode 64 and the p-type electrode 65 have a plurality of rectangular portions having a longitudinal direction formed at predetermined intervals. The rectangular portion of the n-type electrode 64 and the rectangular portion of the p-type electrode 65 are alternately arranged one by one at predetermined intervals in a direction orthogonal to the longitudinal direction of the rectangular portion. The electrode 64 and the p-type electrode 65 are formed in a comb-teeth shape.

  FIG. 14 is an explanatory view showing a conventional solar cell module. The solar cell module 70 is formed by placing the back electrode type solar cell 60 on the wiring substrate 50. In the back electrode type solar cell 60, the n-type electrode 64 and the p-type electrode 65 correspond to the positions corresponding to the comb-shaped n-type wiring 52 and the p-type wiring 53 on the wiring substrate 50, respectively. The n-type wiring 52 and the p-type wiring 53 are electrically connected to the n-type electrode 64 and the p-type electrode 65, respectively.

JP 2011-91327 A

  If the back electrode type solar cell has a fine pitch, which is the interval between the comb-shaped n-type electrode and the p-type electrode, the power generation efficiency of the solar cell increases.

  However, in order to form a solar cell module, the comb-like electrode provided on the back surface of the solar cell is aligned with the comb-like n-type wiring and p-type wiring of the wiring board. In order to prevent the short circuit when the pitch of the n-type electrode and the p-type electrode of the solar battery cell and the pitch of the n-type wiring and the p-type wiring of the wiring sheet are made fine to improve efficiency, High-precision alignment is required, and there is a fear that productivity and reliability may be reduced.

  Even when the pitch is made fine, in order to prevent a short circuit between the n-type electrode and the p-type electrode, the interval between the wirings cannot be reduced. Therefore, the wiring is made narrower in order to narrow the pitch, and there is a problem that the area is reduced and the wiring resistance loss is increased.

  The present invention has been made in view of the above-described problems, and has high productivity and high reliability. The solar cell and the solar cell do not require alignment of the solar cell with high accuracy when the solar cell module is manufactured. Provides a module.

  The solar cell of the present invention is a semiconductor substrate and an i-type amorphous silicon layer and a second conductivity type amorphous silicon layer sequentially on a part of the semiconductor substrate on the side opposite to the light receiving surface of the semiconductor substrate. The second amorphous silicon layer formed by stacking, the second electrode formed on the second amorphous silicon layer, the insulating film formed on the second electrode, and the light receiving surface of the semiconductor substrate A first amorphous silicon layer formed by sequentially laminating an i-type amorphous silicon layer and a first conductivity type amorphous silicon layer on the opposite side from the semiconductor substrate to the insulating film; And a first electrode formed on the silicon layer.

  Moreover, the photovoltaic cell of this invention includes what the 2nd electrode exposes in the outer edge part of at least one side of a photovoltaic cell.

  The solar cell module of the present invention is formed by placing the solar cell on a wiring sheet.

  The method for manufacturing a solar cell according to the present invention includes a first electrode electrically connected to the first conductivity type semiconductor layer on the side opposite to the light receiving surface of the semiconductor substrate, and an electric connection to the second conductivity type semiconductor layer. A method of manufacturing a solar cell having a second electrode connected to the semiconductor substrate, the step of forming a second conductivity type semiconductor layer on a surface opposite to the light receiving surface of the semiconductor substrate; The method includes a step of forming a metal electrode electrically connected to the semiconductor layer and a step of forming an insulating film on the metal electrode.

  Moreover, the manufacturing method of the photovoltaic cell of this invention includes the process of laminating | stacking an i-type amorphous silicon layer and a 1st conductivity type amorphous silicon layer sequentially from the semiconductor substrate to an insulating film.

  According to the present invention, since the shape of the back electrode of the solar battery cell can be simplified, the productivity of the solar battery cell can be improved and the reliability can be increased. Moreover, since the wiring sheet which mounts a photovoltaic cell becomes a simple shape, when manufacturing a solar cell module, highly accurate alignment is unnecessary, Therefore The productivity of a solar cell module can be improved.

It is a schematic diagram of the photovoltaic cell of the present invention. It is a top view of the photovoltaic cell of the present invention. It is typical sectional drawing of the photovoltaic cell of this invention. It is typical sectional drawing which shows the manufacturing process of the photovoltaic cell of this invention. It is typical sectional drawing which shows the manufacturing process of the solar cell module of this invention. It is a top view of the solar cell module of the present invention. It is a top view which shows the photovoltaic cell of this invention. It is typical sectional drawing which shows the manufacturing process of the solar cell module of this invention. It is explanatory drawing of the solar cell module of this invention. It is a schematic diagram of the photovoltaic cell of the present invention. It is typical sectional drawing which shows the manufacturing process of the photovoltaic cell of this invention. It is explanatory drawing which shows the wiring sheet used for the conventional solar cell module. It is explanatory drawing which shows the conventional photovoltaic cell. It is explanatory drawing which shows the conventional solar cell module.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
(Embodiment 1)
FIG. 1 is a schematic view of a solar battery cell 1 of the present invention. An amorphous silicon layer 11 in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially stacked on the silicon substrate 10 is formed on the light-receiving surface side of an n-type silicon substrate 10 which is a first conductivity type semiconductor substrate. Further, an antireflection film 12 in which silicon nitride is laminated is formed thereon.

  Although it is preferable to use n-type single crystal silicon as the silicon substrate 10 from the viewpoint of improving the conversion efficiency of the heterojunction back contact cell, for example, a conventionally known p-type semiconductor substrate may be used. Further, as the silicon substrate 10, it is desirable to use a silicon substrate in which a texture structure is previously formed on the light receiving surface of the silicon substrate.

  Further, an amorphous silicon layer 13 and an amorphous silicon layer 14 are provided on the surface opposite to the light receiving surface of the silicon substrate 10. The amorphous silicon layer 13 is formed by sequentially laminating an i-type amorphous silicon layer to which no impurities are added and a p-type amorphous silicon layer as a second conductivity type semiconductor layer on the silicon substrate 10. In FIG. 2, an i-type amorphous silicon layer and an n-type amorphous silicon layer which is a first conductive type semiconductor layer are sequentially stacked on a silicon substrate 10.

  A p-electrode 15 in which ITO (Indium-Tin-Oxide) and silver are sequentially laminated is formed on the amorphous silicon layer 13 and is electrically connected to the amorphous silicon layer 13. By laminating silver on ITO, the reflectance for reflecting the light that has passed through the amorphous silicon layer is increased, so that the power generation efficiency of the solar battery cell 1 can be increased. In addition, as a metal laminated | stacked on ITO, highly reflective metals, such as what laminated | stacked Ag-Al alloy, Al, Al, and Ni other than silver, can be used. Moreover, you may use transparent electrodes, such as InO and IWO, instead of ITO.

  Further, a metal electrode 16 is formed on the p electrode 15. The metal electrode 16 is formed by sequentially plating nickel and copper on the p electrode 15 by electrolytic plating. The p electrode and the metal electrode 16 are second electrodes that are electrically connected to the amorphous silicon layer 13.

  An insulating film 17 is formed on the surface of the metal electrode 16. The insulating film 17 is an organic insulating film, and is selectively formed on the metal electrode 16 by electrodeposition. As the organic insulating film, epoxy resin or polyamideimide resin is used. For example, Elecoat PI (manufactured by Shimizu Corporation) is used. The thickness is about 5 to 10 μm. Moreover, the insulating film is not formed in the outer side part of the photovoltaic cell, and the metal electrode 16a is exposed.

  An amorphous silicon layer 14 is formed on the surface of the insulating film 17. The amorphous silicon layer 14 is formed on the insulating film 17 and the n-type silicon substrate 10, but they are formed continuously and are formed in the same process as described later.

  On the amorphous silicon layer 14, ITO and silver are sequentially laminated, and an n-electrode 18 that is electrically connected to the amorphous silicon layer 14 is provided. The n electrode 18 as the first electrode is formed by laminating ITO and silver, but may be formed by sequentially laminating nickel and copper instead of silver.

  Since the i-type amorphous silicon layer is laminated on the insulating film 17, even if the insulating film 17 has a defect such as a pinhole, an n-electrode is formed directly on the metal electrode 16 which is a p-type electrode. Never happen.

  FIG. 2 is a plan view of the solar battery cell of the present invention, and is a view of the solar battery cell 1 as viewed from the side opposite to the light receiving surface. The solar battery cell has, for example, a substantially square shape of 156.5 mm × 156.5 mm, and the corner has a round shape. On the back surface, a substantially square n-electrode 18 is formed at the center of the solar battery cell. A metal electrode 16a that is an exposed portion of the outer side of the metal electrode 16 that is electrically connected to the p-electrode is formed on the outer side of the solar cell so as to surround the n-electrode 18. The width of the metal electrode 16a is about 3 mm. The metal electrode 16a does not need to be present on all four sides, and may be installed on a side necessary for connecting to an adjacent solar cell according to the wiring pattern of the solar cell module.

FIG. 3 is a schematic cross-sectional view of the solar battery cell of the present invention, and schematically shows the AA ′ cross-section in FIG. 1. A cross section including an amorphous silicon layer 13 and an amorphous silicon layer 14 formed on the back surface of the silicon substrate 10 is shown. Circular dots of the amorphous silicon layer 14 including the n-type amorphous silicon layer are arranged vertically and horizontally in the amorphous silicon layer 13 including the p-type amorphous silicon layer. The diameter of the dots is about 0.12 to 0.5 mm, and the vertical and horizontal pitches of the dots are preferably about 0.3 to 0.8 mm. For example, in the case of a 156.5 mm square solar cell, when the dot diameter of the n electrode is 0.14 mm and the number of dots is 130,000, the total area of the dots of the n electrode is about 2000 mm ² . It accounts for 8.2%.

  FIG. 4 is a schematic cross-sectional view showing the manufacturing process of the solar battery cell of the present invention. First, as shown in FIG. 4A, a silicon substrate 10 which is an n-type single crystal silicon substrate is prepared.

Next, as shown in FIG. 4B, an amorphous silicon layer 11 in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially stacked is formed on the light receiving surface of the silicon substrate 10. Further, an antireflection film 12 in which a silicon nitride layer is laminated is formed on the light receiving surface side by a sputtering method. Further, an i-type amorphous silicon layer and a p-type amorphous silicon layer are sequentially formed on the surface opposite to the light receiving surface of the silicon substrate 10 to form an amorphous silicon layer 13. The amorphous silicon films 11 and 13 are formed by using plasma CVD. Next, as shown in FIG. 4C, an ITO film is formed on the surface of the amorphous silicon layer 13 formed on the silicon substrate 10 by sputtering. Subsequently, Ag is formed on the ITO film by using a vacuum vapor deposition method to form the p electrode 15.

  Next, as shown in FIG. 4D, a resist pattern is printed on the p electrode 15 to form a mask pattern, the ITO film and the Ag film are etched, and the p electrode 15 is patterned. Further, the mask pattern used for etching is removed with an organic solvent such as acetone.

  Next, as shown in FIG. 4E, nickel and copper are sequentially laminated on the p electrode 15 by electrolytic plating to form the metal electrode 16. At this time, the surface of the metal electrode 16 is covered with copper. In the metal electrode 16, for example, the thickness of nickel is about 2.5 μm and the thickness of copper is about 18 μm.

  Next, as shown in FIG. 4F, a resist film 19 is screen-printed with a width of 1 mm on the surface of at least one side of the metal electrode 16 in the outer side portion of the solar battery cell.

  Next, as shown in FIG. 4G, an insulating film 17 is formed on the metal electrode 16 by electrodeposition. The insulating film 17 is selectively formed only on the metal electrode in contact with the electrodeposition liquid. When Elecoat PI (manufactured by Shimizu Co., Ltd.) is used as the electrodeposition resin, electrodeposition is performed at a liquid temperature of 20 ° C. to 40 ° C., and then temporarily cured in air at 100 ° C. to 150 ° C. for 10 to 20 minutes. The electrodeposition film is cured by heating at 150 to 200 ° C. for about 20 to 40 minutes. In this step, the insulating film 17 is formed on the metal electrode 16 but is not formed on the surface of the amorphous silicon layer 13. That is, the insulating film 17 is selectively formed on the metal electrode.

  Next, as shown in FIG. 4H, the resist film 19 formed on the outer side of the metal electrode 16 is removed using an organic solvent such as acetone. The metal electrode 16a where the insulating film 17 is not formed is exposed.

  Next, as shown in FIG. 4I, alkali etching is performed with an aqueous sodium hydroxide solution, and the amorphous silicon layer of the amorphous silicon layer 13 that is not covered with the metal electrode 16 is removed. The silicon substrate 10 is exposed in the portion where the amorphous silicon layer has been removed. The amorphous silicon layer 13 is selectively etched by using the metal electrode 16 and the insulating film 17 as an etching mask, and it is not necessary to prepare a precise mask pattern at the time of patterning in this step, which leads to cost reduction. In addition, since it is not necessary to perform precise alignment of the mask pattern, production efficiency is improved.

  Next, as shown in FIG. 4J, an amorphous silicon layer 14 is formed by sequentially laminating an i-type amorphous silicon layer and an n-type amorphous silicon layer using a plasma CVD method. The i-type amorphous silicon layer has a thickness of 3 nm, and the n-type amorphous silicon layer has a thickness of about 7 nm. At this time, an amorphous silicon layer is prevented from being formed on the metal electrode 16a by bringing a cell fixing jig into contact with the outer side of the solar battery cell. The cell fixing jig is in contact with the entire circumference of the outer edge of the silicon substrate 10, and in particular, the cell fixing jig is in contact with the portion to be the metal electrode 16a.

  Next, as shown in FIG. 4 (k), an ITO film and an Ag film are sequentially formed on the surface of the amorphous silicon layer 14 by using a thin film forming method such as a sputtering method or a vacuum deposition method, thereby forming an n electrode 18. Thus, the solar battery cell 1 is manufactured. Also in this step, the n-type electrode 18 is prevented from being formed on the metal electrode 16a by bringing the positioning jig into contact with the outer side of the solar battery cell. The solar cells that have been contacted are measured for IV characteristics and checked for power generation performance.

  According to the solar cell process described above, the etching process is performed once by creating a precise mask pattern, and since the mask is not used for the formation of the insulating film 17 and the etching of the amorphous silicon layer 13, the productivity is improved. high.

  FIG. 5 is a schematic cross-sectional view showing the manufacturing process of the solar cell module of the present invention. In FIG. 5A, a conductive resin 20 is applied on the n-electrode 18 on the back surface of the solar battery cell 1 by screen printing.

  Next, as shown in FIG. 5B, the solar battery cell 1 is placed on the wiring sheet 2. The wiring sheet 2 is formed by laminating a PET (Polyethylene terephthalate) resin sheet 21 and a metal foil 22 such as a copper foil or an Al foil having a Ni layer formed on the surface thereof. The metal foil 22 is formed with a pattern-cut groove 24 based on the wiring pattern of the solar cell module, and is electrically separated from the mounting portion of the adjacent solar cell. The conductive resin 23 is preliminarily screen-printed on the wiring sheet 2 so as to come into contact with the metal electrode 16a when the solar battery cell 1 is placed on the wiring sheet 2.

  The photovoltaic cell 1 is placed on the wiring sheet 2 so that the conductive resin 20 and the metal foil 22 are in contact with each other and the metal foil 22a is electrically connected to the metal electrode 16a through the conductive resin 23. Further, the left solar cell 1 a is arranged so as to be electrically connected to the conductive resin 23 a at the left end of the metal foil 22. In this way, a plurality of solar cells are arranged on the wiring sheet 2.

  Next, as shown in FIG.5 (c), the cover glass 30, EVA (ethylene vinyl acetate) resin sheet 31, the photovoltaic cell 1, the wiring sheet 2, the EVA resin sheet 32, and the back sheet 33 are laminated | stacked from the top, and a laminator is used. The solar cell module 3 is formed by pressure bonding.

  FIG. 6 is a plan view of the solar cell module of the present invention. In the wiring sheet 2, a metal foil 22 is disposed on a resin sheet 21, and the metal foil 22 includes metal foils 22 a, 22 b, 22 c, 22 d and the like that are electrically separated by grooves 24.

  Solar cells 1 a, 1 b, 1 c, 1 d are arranged on the wiring sheet 2. The solar cell 1a is placed on the metal foil 22a except for the portion of the metal electrode 16a on one side of the outer side. The n electrode of the solar battery cell 1a is electrically connected to the metal foil 22a.

  On the other hand, the metal electrode 16a on one side of the solar battery cell 1a is on the metal foil 22b and is electrically connected to the metal foil 22b. A metal electrode on the outer side of the solar battery cell placed on the wiring pattern of the metal foil is on the adjacent wiring pattern, and electrically connects the metal electrode and the wiring pattern. Are connected in series.

  In the structure in which the p electrode and the n electrode are arranged side by side, such as a comb-like electrode, about 100 to 200 μm is provided as an interval having a margin between the p electrode and the n electrode in anticipation of an alignment error with the wiring sheet. Since there is no electrode in the space of the interval, there is a fear that the efficiency of collecting the generated carriers with the electrode is lowered. Moreover, it is necessary to increase the alignment accuracy between the wiring sheet and the solar battery cell, and there is a problem in the productivity of the solar battery module.

  On the other hand, the solar cell of the present invention is simple because the n-electrode is disposed in a portion other than the outer peripheral portion of the solar cell and the p-electrode (metal electrode) is disposed in the outer peripheral portion of the solar cell. A module can be configured by placing solar cells on the wiring pattern, and the alignment accuracy between the wiring sheet and the solar cells does not need to be increased, so that productivity is improved.

  Moreover, since the area of the metal foil of the wiring sheet is large and there is no narrow portion, it is advantageous in terms of wiring resistance.

Further, the gap in the surface direction between the p electrode and the n electrode formed on the amorphous silicon layer formed on the opposite side of the light receiving surface of the semiconductor substrate is about 15 μm. Increases efficiency.
(Embodiment 2)
FIG. 7 is a plan view showing a solar battery cell according to another embodiment of the present invention, as viewed from the direction opposite to the light receiving surface. The shape of the exposed part of the electrode on the back surface is different from that of the solar cell of the first embodiment. In the outer side portion of the solar battery cell 4, the n-electrode 18 is formed up to about 1 mm inside from the side in three sides. An n-electrode is formed on the remaining one side of the solar battery cell 4 from the side of the solar battery cell 4 to the inside of about 3 mm. Further, the insulating film 17 is generally exposed at a portion of 2 mm to 3 mm from the end of the solar battery cell 4, and the metal electrode 16 a is exposed at a portion of 1 mm to 2 mm from the end excluding the corner portion of the solar battery cell 4. Yes. Further, a portion where the metal electrode does not exist is provided from the end surface of the solar battery cell 4 to a portion 1 mm from the end, and the silicon substrate 10 is exposed at the portion.

  Since the n-electrode dots formed on the silicon substrate cannot be formed on the exposed portion of the metal electrode 16a, the metal electrode 16a is formed only on one side on the back surface of the solar battery cell 4. By doing so, the area where no electrode exists can be made as small as possible, the carrier collection efficiency can be increased, and the power generation efficiency can be improved.

  Moreover, the part which does not have a metal electrode about 1 mm in width between the metal electrode 16a of the outer peripheral part of the photovoltaic cell 4 and the edge part of a photovoltaic cell is provided. Thus, by providing a portion without the metal electrode between the metal electrode and the end portion of the solar battery cell, the possibility that the metal electrode 16a and the n-type silicon wafer 10 are short-circuited at the outer peripheral portion can be reduced. And reliability can be improved.

  In addition, by forming a portion where the insulating film 17 is exposed, the interval between the n electrode 18 and the exposed metal electrode 16a can be widened, and the tolerance of positional deviation between the cell and the wiring member is increased. Productivity can be increased.

  The structure shown in FIG. 7 can be realized by adjusting the shape of the mask pattern when the insulating film 17 is formed, and the portion that comes into contact with the jig when forming the amorphous silicon film 14 and the n-electrode 18.

  FIG. 8: is typical sectional drawing which shows the manufacturing process of the solar cell module which is another embodiment of this invention. As the n electrode 18 of the solar battery cell 4 used for this solar battery module, an ITO, Ag, Ni, Cu film formed in this order is used. The thickness of Ni is 2.5 μm, and Cu is about 15 μm. Ni and Cu may be formed directly on ITO without forming an Ag film. In Fig.8 (a), when electrically connecting the n electrode 18 of the photovoltaic cell 4 and the metal electrode 16a of the photovoltaic cell 4a which are adjacent to each other, the end of the n electrode 18 of the photovoltaic cell 4 The conductive resin 28 is formed about 1 mm inside from the portion. Further, an insulating resin 27 is formed in a portion extending from the end portion of the n electrode 18 to the end portion of the solar battery cell 4. On the other hand, the conductive resin 26 is disposed on the metal electrode 16a of the solar battery cell 4a. Further, an insulating resin 25 is disposed adjacent to the conductive resin 26 and covers the end portions of the n-electrode 18 and the insulating film 17. The conductive resins 26 and 28 and the insulating resins 25 and 27 are formed by screen printing on the surface opposite to the light receiving surface of the solar battery cell.

  Next, in FIG. 8B, a conductive piece 29 formed of copper foil or the like is disposed so that the conductive resin 26 and the conductive resin 28 are electrically connected. The conductive piece 29 is disposed in contact with the conductive resin 26, the insulating resin 27, and the conductive resin 28. Due to the insulating resin 27, the conductive piece 29 does not contact the metal electrode 16 a of the solar battery cell 4. Further, due to the insulating resin 25, the conductive piece 29 does not contact the n electrode 18 of the solar battery cell 4a.

  Next, as shown in FIG.8 (c), the cover glass 30, EVA resin sheet 31, the photovoltaic cell 4, the conductive piece 29, the EVA resin sheet 32, and the back sheet 33 are laminated | stacked from the top, and it press-presses with a laminator. By doing so, the solar cell module 5 is formed. In the solar cell module 5, a conductive piece of metal foil is partially used for connection with adjacent solar cells, so that no wiring sheet is required, leading to cost reduction.

  FIG. 9 is an explanatory diagram of the solar cell module of the present invention, as viewed from the side opposite to the light receiving surface. Solar cells 4 a and 4 b and 4 b and 4 c are connected in series by conductive pieces 29. There is an interval between the metal electrode 16a and the n electrode 18 by the width where the insulating film is exposed, and the presence of the insulating resin 25 can prevent a short circuit between the metal electrode 16a and the n electrode 18. .

Naturally, the solar battery module shown in FIG. 7 can be formed on the wiring sheet as shown in FIG.
(Embodiment 3)
Next, the details of a solar battery cell according to another embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is that the insulating film is formed of an oxide of a metal electrode. FIG. 10 is a schematic view of the solar battery cell of the present invention. In the solar cell 6, an amorphous silicon layer 11 in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially stacked is formed on the light-receiving surface side of an n-type silicon substrate 10 that is a first conductivity type semiconductor substrate. Further, an antireflection film 12 in which silicon nitride is laminated is formed thereon.

  Although it is preferable to use n-type single crystal silicon as the silicon substrate 10 from the viewpoint of improving the conversion efficiency of the heterojunction back contact cell, for example, a conventionally known p-type semiconductor substrate may be used.

  Further, an i-type amorphous silicon layer and a p-type amorphous silicon layer are sequentially stacked on the silicon substrate 10 on the surface opposite to the light receiving surface of the silicon substrate 10, and an i-type amorphous silicon layer, and an amorphous silicon layer 14 in which an n-type amorphous silicon layer is sequentially stacked on the silicon substrate 10.

  A p-electrode 15 in which ITO and silver are sequentially laminated is formed on the amorphous silicon layer 13 and is electrically connected to the amorphous silicon layer 13. A metal electrode 16 is formed on the p-electrode 15. The metal electrode 16 is formed by sequentially plating nickel and copper by electrolytic plating. Therefore, the outside of the metal electrode is covered with copper.

  An insulating film 47 of a metal oxide film formed by oxidizing the surface of the metal electrode 16 is formed on the surface of the metal electrode 16. In this case, since the metal electrode surface is copper, a copper (II) oxide film is formed as the insulating film 47. The insulating film 47 covers the surface of the metal electrode, but no insulating film is formed on the metal electrode 16a.

  An amorphous silicon layer 14 in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially stacked is formed on the entire surface of the insulating film 47. The amorphous silicon layer 14 is formed on the insulating film 47 and the silicon substrate 10, but they are continuously formed.

  An n-electrode 18 is provided on the amorphous silicon layer 14 by sequentially laminating ITO and silver and electrically connecting to the amorphous silicon layer 14.

  Since the i-type amorphous silicon layer is laminated on the insulating film of the metal oxide film, even if the metal oxide film has a defect such as a pinhole, it is insulated by the amorphous silicon layer having a relatively high resistance value, and the reliability is improved. Get higher.

  The state when the solar battery cell 6 shown in FIG. 10 is viewed from the side opposite to the light receiving surface is the same as in FIG. 10 is the same as that in FIG. 3, and a description thereof will be omitted.

  Next, the manufacturing method of the photovoltaic cell of this Embodiment is demonstrated using FIG. FIG. 11 is a schematic cross-sectional view showing the manufacturing process of the solar battery cell of the present invention.

  First, as shown in FIG. 11A, a silicon substrate 10 which is an n-type single crystal silicon substrate is prepared.

Next, as shown in FIG. 11B, an amorphous silicon layer 11 in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially stacked is formed on the light receiving surface of the silicon substrate 10. Further, an antireflection film 12 in which a silicon nitride layer is laminated is formed on the light receiving surface side by a sputtering method. Further, an i-type amorphous silicon layer and a p-type amorphous silicon layer are sequentially formed on the surface opposite to the light receiving surface of the silicon substrate 10 to form an amorphous silicon layer 13. Next, plasma CVD is used to form the amorphous silicon film. Next, as shown in FIG. 11C, an ITO film is formed on the surface of the amorphous silicon layer 13 formed on the silicon substrate 10 by using the sputtering method. Then, Ag is formed on the ITO film using a vacuum deposition method to form the p-electrode 15.

  Next, as shown in FIG. 11D, a mask pattern is formed on the p-electrode 15 and etched, and the p-electrode 15 is patterned. Further, the mask pattern used for etching is removed. At this stage, a reverse bias voltage is applied from the light receiving surface of the silicon substrate 10 to the p-electrode 15 to remove the short-circuited portion.

  Next, as shown in FIG. 11E, nickel and copper are sequentially laminated on the p electrode 15 by electrolytic plating to form the metal electrode 16. At this time, the surface of the metal electrode 16 is covered with copper. In the metal electrode 16, for example, the thickness of nickel is about 2.5 μm and the thickness of copper is about 18 μm.

  Next, as shown in FIG. 11F, a resist film 19 is screen-printed on the surface of the outer side portion of the solar battery cell.

Next, as shown in FIG. 11 (g), treatment is performed by immersing in an aqueous solution at 80 ° C. to 90 ° C. in which sodium chlorite (NaClO ₂ ) and sodium hydroxide (NaOH) are dissolved for 2 to 10 minutes. As a result, the copper on the surface of the metal electrode is oxidized to form a black thin film insulating film 47 of copper (II) oxide. In addition, the amorphous silicon layer 13 where there is no metal electrode is etched, and the surface of the silicon substrate 10 is exposed. The amorphous silicon layer 13 is etched by using the metal electrode as a mask. The insulating film 47 is selectively formed on the metal electrode, and the amorphous silicon layer 13 is etched using the metal electrode as an etching mask. Therefore, since it is not necessary to prepare a precise mask pattern at the time of patterning in this step, the cost is reduced and production efficiency is improved because it is not necessary to perform precise alignment.

  Next, as shown in FIG. 11H, the remaining resist film 19 is removed using an organic solvent such as acetone. The metal electrode 16a where the insulating film is not formed is exposed.

  Next, as shown in FIG. 11I, an amorphous silicon layer 14 is formed by sequentially laminating an i-type amorphous silicon layer and an n-type amorphous silicon layer using a plasma CVD method. At this time, an amorphous silicon layer is prevented from being formed on the metal electrode 16a by bringing a positioning jig into contact with the metal electrode 16a.

  Next, as shown in FIG. 11 (j), an ITO film is formed on the surface of the amorphous silicon layer 14 by sputtering, and then Ag is formed on the ITO film by vacuum evaporation to form an n-electrode 18. The solar battery cell 6 is manufactured by forming. In this step, the n-electrode 18 is prevented from being formed on the metal electrode 16a by bringing a cell fixing jig into contact with the outer edge of the solar battery cell. The completed solar cell is measured for IV characteristics and checked for power generation performance.

  The solar battery cell described in the third embodiment can form a solar battery module in the same manner as that described in the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1, 4, 6 ... Solar cell 2 ... Wiring sheet 3, 5 ... Solar cell module 10 ... Silicon substrate 11 ... Amorphous silicon layer 12 ... Antireflection film 13 ... Amorphous silicon layer 14 ... Amorphous silicon layer 15 ... P electrode 16 ... Metal electrode 16a ... Metal electrode 17 ... Insulating film 18 ... N electrode 19 ... Resist film 20 ... Conductive resin 21 ... Resin sheet 22 ... Metal foil 23 ... Conductive resin 24 ... Groove 25 ... Insulating resin 26 ... Conductive resin 27 ... Insulating resin 28 ... conductive resin 29 ... conductive piece 30 ... cover glass 31 ... EVA resin sheet 32 ... EVA resin sheet 33 ... back sheet 47 ... insulating film

Claims (5)

A semiconductor substrate;
Second amorphous silicon formed by sequentially laminating an i-type amorphous silicon layer and a second conductivity type amorphous silicon layer on a part of the semiconductor substrate on the side opposite to the light receiving surface of the semiconductor substrate. Layers,
A second electrode formed on the second amorphous silicon layer;
An insulating film formed on the second electrode;
A first substrate formed on an opposite side of the light-receiving surface of the semiconductor substrate and sequentially laminating an i-type amorphous silicon layer and a first conductivity type amorphous silicon layer from the semiconductor substrate to the insulating film; An amorphous silicon layer;
A first electrode formed on the first amorphous silicon layer;
A solar battery cell.   The solar cell according to claim 1, wherein the second electrode is exposed in an outer side portion of at least one side of the solar cell.   The solar cell module formed by mounting the photovoltaic cell of Claim 1 or Claim 2 on the wiring sheet. A sun having a first electrode electrically connected to the first conductivity type semiconductor layer and a second electrode electrically connected to the second conductivity type semiconductor layer on the opposite side of the light receiving surface of the semiconductor substrate A battery cell manufacturing method comprising:
Forming a second conductivity type semiconductor layer on a surface opposite to the light receiving surface of the semiconductor substrate;
Forming a metal electrode electrically connected to the semiconductor layer of the second conductivity type;
Forming an insulating film on the metal electrode;
The manufacturing method of the photovoltaic cell containing this.   The manufacturing method of the photovoltaic cell of Claim 4 including the process of laminating | stacking an i-type amorphous silicon layer and a 1st conductivity type amorphous silicon layer sequentially from the said semiconductor substrate over the said insulating film.