JP2022011614A - Solar cell module - Google Patents

Abstract

To provide a solar cell module comprising a back-contact solar battery cell, capable of improving an output characteristic.SOLUTION: Each of a plurality of solar cells 20 structuring a solar cell module, contains: a photoelectric conversion part 21 in which an n-type region 23 and a p-type region 24 are alternately formed to a first direction on a main surface; an n-side electrode layer 30; a p-side electrode layer 31; an n-side insulation layer 36; a p-side insulation layer 37; an n-side contact electrode 38; and a p-side contact electrode 39. The n-side insulation layer 36 covers a whole region on the n-side electrode layer 30 excluding a part where the n-side contact electrode 38 is formed. The p-side insulation layer 37 covers a whole region on the p-side electrode layer 31 excluding a part where the p-side contact electrode 39 is formed. Each of a plurality of wiring materials 50 is extended to a first direction, and is connected to at least one of the n-side contact electrode 38 and the p-side contact electrode 39.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a solar cell module, and more particularly to a solar cell module including a back surface bonded type solar cell in which an electrode is formed only on one main surface of a photoelectric conversion unit.

Conventionally, a back surface bonding type including a silicon wafer, first and second semiconductor layers formed on one main surface of the wafer, and first and second electrodes formed on each semiconductor layer, respectively. Solar cells are known (see, for example, Patent Document 1). Further, Patent Document 2 discloses a solar cell module including a string in which adjacent backside-bonded solar cell cells are connected by a rectangular plate-shaped wiring material. The wiring material connects the n-side electrode formed on the n-type semiconductor layer of one cell and the p-side electrode formed on the p-type semiconductor layer of the other cell between adjacent solar cells. ing.

Patent No. 5879515 Patent No. 6341437

The back surface bonded type solar cell can utilize sunlight more effectively and can realize high photoelectric conversion efficiency as compared with the solar cell having electrodes formed on both sides. However, in the conventional solar cell module as disclosed in Patent Document 2, a region that does not contribute to power generation (when an n-type silicon wafer is used, an n-type semiconductor layer is formed in a portion connecting a plate-shaped wiring material). It is necessary to form a large area). Further, it is required to improve the collection efficiency and efficiently take out the electricity generated by the solar cell to further improve the output characteristics of the solar cell module.

An object of the present disclosure is to improve the output characteristics of a solar cell module including a back-bonded solar cell.

The solar cell module according to one aspect of the present disclosure is a solar cell module including a plurality of solar cell cells and a plurality of wiring materials connected to at least one of the plurality of solar cell cells. Each of the solar cell cells has a photoelectric conversion unit in which n-type regions and p-type regions are alternately formed in the first direction on the main surface, an n-side electrode layer formed on the n-type region, and the above. The p-side electrode layer formed on the p-type region, the n-side insulating layer formed on the n-side electrode layer, the p-side insulating layer formed on the p-side electrode layer, and the n-side insulation. The n-side contact electrode connected to the n-side electrode layer via the opening of the layer and the p-side contact electrode connected to the p-side electrode layer through the opening of the p-side insulating layer are included. The n-side insulating layer covers the entire area on the n-side electrode layer excluding the portion where the n-side contact electrode is formed, and the p-side insulating layer excludes the portion where the p-side contact electrode is formed. Covering the entire area on the p-side electrode layer, each of the plurality of wiring materials extends in the first direction and is connected to at least one of the n-side contact electrode and the p-side contact electrode.

According to one aspect of the present disclosure, the output characteristics can be improved in a solar cell module including a back-bonded solar cell. The solar cell module according to the present disclosure has, for example, a small number of invalid regions of the solar cell that does not contribute to power generation. In addition, it is possible to efficiently take out the generated electricity with high current collection efficiency.

It is sectional drawing of the solar cell module which is an example of Embodiment. It is sectional drawing of the solar cell which is an example of an embodiment. It is a perspective view which saw one solar cell which constitutes the solar cell module which is an example of Embodiment from the back side. In the solar cell module which is an example of an embodiment, it is a perspective view which looked at two adjacent solar cell cells from the back side. It is a figure which shows the modification of the connection pattern of the wiring material with respect to a solar cell. It is a figure which shows the modification of the connection pattern of the wiring material with respect to a solar cell. It is a figure which shows the modification of the connection pattern between solar cells. It is a figure which shows an example of the connection pattern of the solar cell divided into a plurality of subcells, and the wiring material with respect to a subcell. It is a figure which shows an example of the connection pattern between cells in the case of using the solar cell divided into a plurality of subcells. It is a figure which shows another example of the connection pattern between cells in the case of using the solar cell divided into a plurality of subcells. It is a figure which shows an example of the connection structure of the wiring material with respect to a solar cell. It is a figure which shows another example of the connection structure of the wiring material to a solar cell. It is a figure which shows another example of the connection structure of the wiring material to a solar cell. It is a figure which shows another example of the connection structure of the wiring material to a solar cell. It is a figure which shows another example of the connection structure of the wiring material to a solar cell. It is a figure which shows an example of the cross-sectional structure of a contact electrode and its vicinity. It is a figure which shows another example of the cross-sectional structure of a contact electrode and its vicinity. It is a figure for demonstrating the manufacturing method of the solar cell module which is an example of embodiment. It is a figure which shows the modification of the formation pattern of the semiconductor layer of a solar cell. It is a figure which shows the modification of the formation pattern of the semiconductor layer of a solar cell. It is a figure which shows the modification of the formation pattern of the semiconductor layer of a solar cell. It is a figure which shows the modification of the formation pattern of a contact electrode. It is a figure which shows the modification of the formation pattern of a contact electrode. It is a figure which shows the modification of the formation pattern of a contact electrode.

Hereinafter, an example of the embodiment of the solar cell module according to the present disclosure will be described in detail with reference to the drawings. The solar cell module according to the present disclosure is not limited to the embodiment described below. The drawings referred to in the description of the embodiment are schematically described, and the dimensional ratios of the components drawn in the drawings should be determined in consideration of the following description. In addition, a form in which the configurations of a plurality of embodiments and modifications described below are selectively combined is assumed from the beginning.

In the drawings referred to in the description of the embodiment, the first direction in which the n-type region and the p-type region of the solar cell are alternately arranged is indicated by an arrow X. Further, the thickness direction of the solar cell (solar cell module) is indicated by an arrow Z, and the first direction and the second direction orthogonal to the thickness direction are indicated by an arrow Y.

FIG. 1 is a cross-sectional view of a solar cell module 10 which is an example of an embodiment. As illustrated in FIG. 1, the solar cell module 10 includes a plurality of solar cell 20s and a plurality of wiring materials 50 connected to at least one of the plurality of solar cell 20s. Further, the solar cell module 10 is located between the first protective member 11 provided on the light receiving surface side of the solar cell 20 and the second protective member 12 provided on the back surface side of the solar cell 20 and each protective member. The sealing material 13 filled in the above is provided. A metal frame may be attached to the peripheral edge of the solar cell panel in which a plurality of solar cell 20, two protective members, and a sealing material 13 are laminated.

Here, the light receiving surface of the solar cell 20 means the main surface on which sunlight is mainly incident (over 50% to 100%), and the "back surface" means the main surface opposite to the light receiving surface. .. In this specification, the terms of the light receiving surface and the back surface are also used for the photoelectric conversion unit 21 and the like.

The plurality of solar cells 20 are arranged on the same plane, for example, and the adjacent solar cells 11 are connected to each other by a wiring material 50. The solar cell 20 is a back surface bonding type cell in which electrodes are formed only on the back surface side, and the wiring material 50 is arranged only on the back surface side of the solar cell 20. Therefore, more sunlight is incident from the light receiving surface of the solar cell 20 than in the case where the electrode is formed on the light receiving surface of the cell and the wiring material is arranged on the light receiving surface side.

In the solar cell module 10, generally, a plurality of solar cell 20s are arranged in a row, and a plurality of strings connected in series by a wiring material 50 exist. The plurality of strings are arranged parallel to each other, for example. In the example shown in FIG. 1, an inter-cell wiring material 60 arranged so as to be orthogonal to the wiring material 50 is provided between two adjacent solar cell cells 20. The wiring material 50 is connected to the cell-to-cell wiring material 60, and a plurality of solar cell 20s are connected in series via the cell-to-cell wiring material 60.

For the first protective member 11, for example, a translucent glass substrate, a resin substrate, or the like is used. The first protective member 11 is generally flat, but may be curved. As the second protective member 12, the same transparent member as the first protective member 11 may be used, or an opaque member may be used. For the second protective member 12, for example, a resin sheet having a thickness thinner than that of the first protective member 11 can be used. The material of the resin sheet is not particularly limited, and examples of suitable resins include polyethylene terephthalate (PET).

The sealing material 13 is filled between the first protective member 11 and the second protective member 12, protects the solar cell 20 from moisture and the like, and fixes the cell so that the solar cell 20 does not move significantly. The sealing material 13 is generally arranged between the first protective member 11 and the solar cell 20 and the first resin sheet, and between the solar cell 20 and the second protective member 12. A second resin sheet is used. In the solar cell module 10, a string in which a plurality of solar cell 20s are connected in series by a wiring material 50 is arranged between two resin sheets constituting the sealing material 13, and the laminated body is protected by two sheets. Manufactured by sandwiching between members and laminating.

FIG. 2 is a cross-sectional view of the solar cell 20, and FIG. 3 is a perspective view of the solar cell 20 as viewed from the back surface side. As illustrated in FIGS. 2 and 3, the solar cell 20 includes a photoelectric conversion unit 21 in which n-type regions 23 and p-type regions 24 are alternately formed in the first direction on the back surface. The photoelectric conversion unit 21 includes a substrate 22 and two types of semiconductor layers (n-type semiconductor layer 25 and p-type semiconductor layer 26) formed on the back surface of the substrate 22, and generates carriers by receiving sunlight. do. On the back surface of the substrate 22, the region where the n-type semiconductor layer 25 is formed becomes the n-type region 23, and the region where the p-type semiconductor layer 26 is formed becomes the p-type region 24.

As the substrate 22, a semiconductor substrate such as crystalline silicon, gallium arsenide, or indium phosphide can be used. Above all, it is preferable to use an n-type single crystal silicon wafer. The thickness of the substrate 22 is, for example, 50 to 300 μm. It is preferable that a texture structure (not shown) is formed on the surface of the substrate 22. The texture structure is a surface uneven structure for suppressing surface reflection and increasing the amount of light absorption of the substrate 22, preferably formed on at least the light receiving surface, and is formed on both the light receiving surface and the back surface. May be good. The substrate 22 may have, for example, a substantially square shape in a plan view, and the corners of the square may be cut diagonally.

A protective layer 28 is formed on the light receiving surface side of the substrate 22. The protective layer 28 is an insulating layer made of, for example, silicon nitride, silicon oxide, silicon oxynitride, etc., and also functions as an antireflection layer that suppresses reflection of incident light. Further, it is preferable that a passivation layer 29 that suppresses carrier recombination on the light receiving surface side of the substrate 22 is interposed between the substrate 22 and the protective layer 28. An example of the passivation layer 29 has a substantially intrinsic amorphous silicon layer (hereinafter, may be referred to as “i-type amorphous silicon layer”) or a dopant concentration lower than that of the n-type semiconductor layer 25 described later. It is an amorphous silicon layer.

As described above, the n-type semiconductor layer 25 and the p-type semiconductor layer 26 are formed on the back surface side of the substrate 22. For example, the substrate 22 is an n-type single crystal silicon wafer, the n-type semiconductor layer 25 is an n-type amorphous silicon layer, and the p-type semiconductor layer 26 is a p-type amorphous silicon layer. On the back surface of the n-type single crystal silicon wafer, an n-type region 23 doped with n-type by the n-type semiconductor layer 25 and a p-type region 24 doped with p-type by the p-type semiconductor layer 26 are formed. ..

The n-type semiconductor layer 25 is formed in the first region on the back surface of the substrate 22, and the p-type semiconductor layer 26 is formed in the second region on the back surface of the substrate 22. Further, the insulating layer 27 is formed on a part of the n-type semiconductor layer 25, and the p-type semiconductor layer 26 is formed on the second region and the insulating layer 27. The n-type semiconductor layer 25 and the p-type semiconductor layer 26 are partially overlapped with each other via the insulating layer 27, and are formed over a wide area on the back surface without gaps. The region where the semiconductor layer is formed is, for example, the entire area excluding the peripheral edge of the back surface of the substrate 22.

As illustrated in FIG. 3, the n-type region 23 formed by the n-type semiconductor layer 25 and the p-type region 24 formed by the p-type semiconductor layer 26 alternate in the first direction on the back surface of the solar cell 20. It is formed in a stripe shape side by side. Further, the n-type region 23 and the p-type region 24 extend in the second direction of the back surface of the solar cell 20, and are formed in a fine line shape or a band shape from one end to the other end in the second direction.

The n-type region 23 and the p-type region 24 extend in parallel with each other, for example, and have the same length. In the example shown in FIG. 3, each of the n-type regions 23 is not connected to each other and is separated by the p-type region 24. Similarly, each of the p-type regions 24 is not connected to each other and is separated by an n-type region 23. The plurality of n-type regions 23 are formed to have the same width, but the widths of the respective n-type regions 23 do not have to be constant (the same applies to the p-type region 24).

The widths of the n-type region 23 and the p-type region 24 may be the same as each other, but preferably the width of the p-type region 24> the width of the n-type region 23. An example of the width of the n-type region 23 is 0.1 mm to 0.5 mm, and an example of the width of the p-type region 24 is 0.2 mm to 1 mm. Further, the number of p-type regions 24 may be larger than the number of n-type regions 23. In the example shown in FIG. 3, p-type regions 24 are formed at both ends of the back surface of the substrate 22 in the first direction, and one more p-type regions 24 are formed than the n-type regions 23.

Forming the p-type region 24 in a larger area than the n-type region 23, in other words, forming a conductive type semiconductor layer different from the conductive type of the semiconductor constituting the substrate 22 in a large area is a method of forming the solar cell 20 in a large area. Contributes to the improvement of output characteristics. As will be described in detail later, in the solar cell module 10, since the wiring material 50 is connected to the contact electrodes provided in each of the n-type region 23 and the p-type region 24, the current collecting efficiency is high and the generated electricity is efficiently used. It is possible to take it out. Further, it is not necessary to form a large invalid region that does not contribute to power generation in order to secure the connection portion of the wiring material as in the conventional case. Therefore, the solar cell module 10 has excellent output characteristics.

The n-type semiconductor layer 25 may have a single-layer structure of an n-type amorphous silicon layer, but is preferably a multi-layer structure of an i-type amorphous silicon layer and an n-type amorphous silicon layer, or an n-type. It is a multi-layer structure consisting of an amorphous silicon layer and an n-type amorphous silicon layer having a dopant concentration lower than that of the amorphous silicon layer. The i-type amorphous silicon layer and the n-type amorphous silicon layer having a low dopant concentration function as a passivation layer that suppresses carrier recombination on the back surface of the substrate 22.

Similarly, the p-type semiconductor layer 26 may have a single-layer structure of a p-type amorphous silicon layer, but preferably a multi-layer structure of an i-type amorphous silicon layer and a p-type amorphous silicon layer. Alternatively, it has a multi-layer structure of an amorphous silicon layer and a p-type amorphous silicon layer having a dopant concentration lower than that of the p-type amorphous silicon layer. The i-type amorphous silicon layer and the p-type amorphous silicon layer having a low dopant concentration function as a passivation layer that suppresses carrier recombination on the back surface of the substrate 22.

The concentration of the dopant in the n-type amorphous silicon layer and the p-type amorphous silicon layer is, for example, 1 × 10 ²⁰ atoms / cm ³ or more. Generally, phosphorus (P) is used as the n-type dopant, and boron (B) is used as the p-type dopant. An example of the thickness of each semiconductor layer is 1 to 25 nm. The insulating layer 27 is, for example, a layer having the same composition as the protective layer 28, and is composed of silicon nitride, silicon oxide, silicon oxynitride, or the like. Each semiconductor layer and the insulating layer 27 can be formed into a film by CVD or sputtering.

As illustrated in FIGS. 2 and 3, the solar cell 20 has an n-side electrode layer 30 formed on the n-type region 23 (n-type semiconductor layer 25) of the photoelectric conversion unit 21 and a p-type region 24 (p-type region 24). It includes a p-side electrode layer 31 formed on the p-type semiconductor layer 26). Further, an n-side insulating layer 36 and an n-side contact electrode 38 are formed on the n-side electrode layer 30. Similarly, the p-side insulating layer 37 and the p-side contact electrode 39 are formed on the p-side electrode layer 31. The n-side contact electrode 38 is connected to the n-side electrode layer 30 via the opening of the n-side insulating layer 36, and the p-side contact electrode 39 is connected to the p-side electrode layer 31 via the opening of the p-side insulating layer 37. It is connected to the.

The n-side electrode layer 30 is an electrode that collects carriers from the n-type region 23, and is formed on the n-type region 23. The p-side electrode layer 31 is an electrode that collects carriers from the p-type region 24 and is formed on the p-type region 24. The n-side electrode layer 30 and the p-side electrode layer 31 are separated by a groove 48 extending in the second direction, and are alternately arranged in the first direction to form a stripe. The groove 48 is preferably formed at a position overlapping the insulating layer 27.

The n-side electrode layer 30 preferably has a multi-layer structure including a transparent conductive layer 32 formed on the n-type region 23 and a metal layer 33 formed on the transparent conductive layer 32. Similarly, the p-side electrode layer 31 preferably has a multi-layer structure including a transparent conductive layer 34 formed on the p-shaped region 24 and a metal layer 35 formed on the transparent conductive layer 34. As will be described in detail later, for the n-side electrode layer 30 and the p-side electrode layer 31, for example, after forming an electrode layer (transparent conductive layer and metal layer) by sputtering over substantially the entire back surface of the photoelectric conversion unit 21, the electrode layer (transparent conductive layer and metal layer) is formed. It is formed by etching a part thereof to provide a groove 48.

The transparent conductive layers 32 and 34 are generally transparent conductive oxides (IWO) obtained by doping metal oxides such as indium oxide (In ₂ O ₃ ) and zinc oxide (ZnO) with W, Sn, Sb and the like. , ITO, etc.). An example of the thickness of the transparent conductive layers 32 and 34 is 30 nm to 500 nm, preferably 50 nm to 200 nm. The transparent conductive layers 32 and 34 are formed by, for example, sputtering.

The metal layers 33 and 35 are made of, for example, a metal such as Cu, Ni, or Ag, and may have a single-layer structure containing Cu as a main component, or may have a multi-layer structure of a Cu layer and a Ni layer. good. Further, a Sn layer may be formed on the outermost surfaces of the metal layers 33 and 35. An example of the thickness of the metal layers 33 and 35 is 50 nm to 1 μm, preferably 80 nm to 500 nm. The metal layers 33 and 35 are formed by, for example, sputtering.

The n-side insulating layer 36 is formed on the n-side electrode layer 30, and covers the entire area on the n-side electrode layer 30 except for the portion where the n-side contact electrode 38 is formed. As used herein, the term "whole area" includes what is deemed to be substantially the whole area. The presence of the n-side insulating layer 36 that covers the entire area on the n-side electrode layer 30 makes it highly effective that the wiring material 50 electrically connected to the adjacent p-side electrode layer 31 comes into contact with the n-side electrode layer 30. Can be suppressed. An opening 46 is formed in the n-side insulating layer 36 at a portion where the n-side contact electrode 38 is formed, and the n-side contact electrode 38 is connected to the n-side electrode layer 30 via the opening 46. ..

The p-side insulating layer 37 is formed on the p-side electrode layer 31, and covers the entire area on the p-side electrode layer 31 except for the portion where the p-side contact electrode 39 is formed. The presence of the p-side insulating layer 37 covering the entire area on the p-side electrode layer 31 makes it possible for the wiring material 50 electrically connected to the adjacent n-side electrode layer 30 to come into contact with the p-side electrode layer 31. It can be highly suppressed. An opening 47 is formed in the p-side insulating layer 37 at a portion where the p-side contact electrode 39 is formed, and the p-side contact electrode 39 is connected to the p-side electrode layer 31 via the opening 47. ..

When the metal layers 33 and 35 contain Cu, copper damage in which Cu ions diffuse into the encapsulant 13 and promote oxidative deterioration of the resin may become a problem, but an insulating layer covering the entire area on the metal layers 33 and 35 may be a problem. By providing the above, deterioration of the sealing material 13 due to copper damage can be suppressed. Therefore, the configuration in which the insulating layer covering the entire area of the metal layers 33 and 35 is arranged is more suitable when the metal layers 33 and 35 contain Cu.

The n-side insulating layer 36 and the p-side insulating layer 37 are separated by a groove 49 extending in the second direction, and are alternately arranged in the first direction to form a stripe. As will be described in detail later, the n-side insulating layer 36 and the p-side insulating layer 37 can be used as a mask when forming a groove 48 for separating the electrode layer. Each insulating layer may be formed in a striped pattern having grooves 49 by printing or the like, and a continuous insulating layer is formed on substantially the entire back surface of the photoelectric conversion unit 21 and then a part thereof is removed. It may be formed by providing the groove 49.

The insulating layer may be an inorganic compound layer such as silicon nitride, silicon oxide, or silicon oxynitride, or a resin layer such as an acrylic resin. The insulating layer varies depending on, for example, a constituent material, and has a thickness of about 30 nm to 500 nm in the case of an inorganic compound layer and about 1 μm to 20 μm in the case of a resin layer. When a part of the insulating layer is removed to form the groove 49, the insulating layer may be removed by etching or may be removed by irradiating a laser beam such as a CO ₂ laser or an IR laser.

When a resin layer is used as the insulating layer and the resin layer is irradiated with laser light to form a groove 49, a resin layer containing a resin having a high absorption rate of laser light as a main component may be provided. Alternatively, a layer having a high laser light absorption rate may be provided between the electrode layer and the resin layer, and an additive having a high laser light absorption rate may be contained in the resin layer. Further, when the inorganic compound layer is used as the insulating layer, there are advantages such as easy processing of the groove 49 by irradiation with laser light and high heat resistance.

The n-side contact electrode 38 is a portion to which the wiring material 50 is connected, and protrudes from the n-side insulating layer 36 to the back side of the solar cell 20. That is, the n-side contact electrode 38 is formed on the n-side electrode layer 30 to be thicker than the n-side insulating layer 36. It is preferable that the n-side contact electrode 38 is surrounded by the n-side insulating layer 36 in the rear view of the solar cell 20.

A plurality of n-side contact electrodes 38 are arranged at predetermined intervals in the second direction in which the n-type region 23 extends. The n-side contact electrode 38 is formed, for example, at a ratio of 1/2 or more of the number of wiring materials 50 arranged on the back surface of the solar cell 20 along the longitudinal direction (second direction) of the n-type region 23. Will be done. Further, in the example shown in FIG. 3, the same number of n-side contact electrodes 38 are formed in each of the n-type regions 23, and the n-side contact electrodes 38 are arranged in the first direction.

Similar to the n-side contact electrode 38, the p-side contact electrode 39 is a portion to which the wiring material 50 is connected, and is formed on the p-side electrode layer 31 thicker than the p-side insulating layer 37, and is a p-side insulating layer. It protrudes from 37 to the back side of the solar cell 20. Further, the p-side contact electrode 39 is surrounded by the p-side insulating layer 37 in the rear view of the solar cell 20. In the present embodiment, since the p-type region 24 is formed wider than the n-type region 23, the width of the p-side contact electrode 39> the width of the n-side contact electrode 38.

A plurality of p-side contact electrodes 39 are arranged at predetermined intervals in the second direction in which the p-type region 24 extends. In the example shown in FIG. 3, a number of p-side contact electrodes 39 corresponding to ½ of the number of wiring materials 50 are formed at equal intervals in the longitudinal direction (second direction) of the p-type region 24. Further, the same number of p-side contact electrodes 39 are formed in each of the p-type regions 24, and the p-side contact electrodes 39 are lined up in the first direction.

Each contact electrode is formed, for example, at the same height. As will be described in detail later, the contact electrode is provided by printing a metal paste on an insulating layer having an opening and firing it. The metal paste constituting the contact electrode is not particularly limited, but is preferably a silver paste from the viewpoint of conductivity. By arranging the contact electrodes at intervals in the second direction, the amount of silver paste used can be reduced, and the manufacturing cost of the solar cell module 10 can be reduced.

The n-side contact electrode 38 and the p-side contact electrode 39 are arranged in a staggered manner along the second direction. In the example shown in FIG. 3, the number of n-side contact electrodes 38 formed in each of the n-type regions 23 and the number of p-side contact electrodes 39 formed in each of the p-type regions 24 are the same. The distance between the n-side contact electrode 38 and the p-side contact electrode 39 in the second direction is, for example, constant and is about ½ of the distance between the n-side contact electrodes 38 in the second direction. That is, the p-side contact electrode 39 is arranged between the two n-side contact electrodes 38 in the second direction. Similarly, the n-side contact electrode 38 is arranged in the middle of the two p-side contact electrodes 39 in the second direction.

As illustrated in FIG. 3, a plurality of wiring materials 50 are attached to the back surface of one solar cell 20. Each of the plurality of wiring materials 50 extends in the first direction and is connected to at least one of the n-side contact electrode 38 and the p-side contact electrode 39. The wiring material 50 is connected to the n-side contact electrode 38 or the p-side contact electrode 39 in one solar cell 20 that does not include a subcell described later. The wiring materials 50 are arranged in parallel with each other, for example, at predetermined intervals in the second direction. The distance between the wiring materials 50 corresponds to the distance between the contact electrodes, and the wiring materials 50 are preferably arranged at equal intervals in the second direction.

The wiring material 50 is a thin wire-shaped metal member, and is generally called an interconnector. In the following, unless otherwise specified, the wiring material extending in the first direction on the back surface of the solar cell 20 is referred to as the wiring material 50. The cross-sectional shape of the wiring material 50 may be either a rectangular shape or a perfect circular shape. Round lumber is cheaper than square lumber, but the contact area with the contact electrode tends to be small. The wiring material 50 is made of, for example, a metal containing aluminum as a main component. An example of the width of the wiring material 50 is 0.3 mm to 3 mm. In the example shown in FIG. 3, the width of one contact electrode is formed to be larger than the width of the wiring material 50.

FIG. 4 is a perspective view of two adjacent solar cells 20 as viewed from the back surface side. In the example shown in FIG. 4, of the two adjacent solar cells 20, the wiring material 50 connected to the n-side contact electrode 38 of one of the solar cells 20 (hereinafter referred to as “solar cell 20A”) is , Is connected to the inter-cell wiring material 60 arranged between the cells. Further, the wiring material 50 connected to the p-side contact electrode 39 of the other solar cell 20 (hereinafter referred to as “solar cell 20B”) is connected to the cell-to-cell wiring material 60.

That is, the n-side electrode layer 30 of the solar cell 20A and the p-side electrode layer 31 of the solar cell 20B are electrically connected via the wiring material 50 and the inter-cell wiring material 60. The wiring material 50 connected to the p-side contact electrode 39 of the solar cell 20A is electrically connected to the solar cell 20 arranged on the opposite side of the solar cell 20B, and is on the n side of the solar cell 20B. The wiring material 50 connected to the contact electrode 38 is electrically connected to the solar cell 20 arranged on the opposite side of the solar cell 20A. In this way, a string in which a plurality of solar cell 20s are connected in series is formed.

The inter-cell wiring material 60 is arranged in a gap formed between the solar cell 20A and 20B, extends in the second direction, and is orthogonal to the wiring material 50. The same member as the wiring material 50 may be used for the inter-cell wiring material 60, but a square material wider than the wiring material 50 is preferably used from the viewpoint of connectivity with the wiring material 50 and the like. The wiring material 50 may be welded to the inter-cell wiring material 60, or may be connected by using solder, an adhesive, or the like.

In the example shown in FIG. 4, the n-side contact electrode 38 of the solar cell 20A and the n-side contact electrode 38 of the solar cell 20B are arranged side by side in the first direction. Similarly, the p-side contact electrode 39 of the solar cell 20A and the p-side contact electrode 39 of the solar cell 20B are arranged in the first direction. That is, the same solar cell 20 is arranged in the same direction. In this case, the cell-to-cell wiring material 60 is used to connect the solar cells 20A and 20B.

5 and 6 are diagrams showing a modified example of the connection pattern of the wiring material 50 with respect to the solar cell 20. Since the arrangement of the wiring material 50 depends on the formation pattern of the contact electrode, it can be said to be a modification of the formation pattern of the contact electrode. In FIGS. 5 and 6, the wiring material 50 connected to the n-side contact electrode 38 is referred to as a “wiring material 51”, and the wiring material 50 connected to the p-side contact electrode 39 is referred to as a “wiring material 52”.

As illustrated in FIG. 5, the n-side contact electrode 38 and the p-side contact electrode 39 may be arranged close to each other so as to be paired with each other. In the example shown in FIG. 5, in the second direction, the p-side contact electrode 39 is not arranged between the two n-side contact electrodes 38, but is arranged close to one n-side contact electrode 38 and the other n-side contact electrode. The distance from 38 is large. It is preferable that the set of the n-side contact electrode 38 and the p-side contact electrode 39 arranged in close proximity to each other are formed so as not to overlap each other in the first direction.

In the example shown in FIG. 5, the wiring material 51 connected to the n-side contact electrode 38 and the wiring material 52 connected to the p-side contact electrode 39 are arranged in close proximity to each other so as to form a pair. In this case, the alignment accuracy of the wiring materials 51 and 52 becomes strict, but there is an advantage that both the wiring materials 51 and 52 can be arranged up to the vicinity of both ends in the second direction of the solar cell 20. It is preferable that the distance between the pair of wiring materials 51 and 52 in the second direction is constant.

As illustrated in FIG. 6, the number of wiring materials 51 and 52 connected to one solar cell 20 may be different. In the example shown in FIG. 6, the n-side contact electrodes 38 are formed side by side in the first direction at both ends in the second direction, and the wiring material 51 is provided at both ends in the second direction. That is, one more wiring material 51 is provided than the wiring material 52. Since the n-side electrode layer 30 has a narrower width and a higher resistance than the p-side electrode layer 31, the resistance at the n-side electrode is obtained by providing one more wiring material 51 and arranging the wiring materials 51 at both ends in the second direction. Loss can be suppressed.

FIG. 7 is a diagram showing a modified example of the connection pattern of the adjacent solar cell 20. In the example shown in FIG. 7, two strings composed of two solar cell 20 are illustrated, but the number of strings constituting the solar cell module 10 and the number of solar cell 20 are not particularly limited. The four solar cells 20A, 20B, 20C, and 20D shown in FIG. 7 are the same cells.

The solar cell module 10 generally includes a terminal box 14 containing a bypass diode. Further, a crossover wiring material 61 for electrically connecting the strings to each other and an output wiring material 62 connected to the terminal box 14 are provided. In the example shown in FIG. 7, the crossover wiring material 61 is arranged on one end side of the string along the second direction, and the output wiring material 62 is arranged on the other end side of the string along the second direction. As the crossover wiring material 61 and the output wiring material 62, the same members as the cell-to-cell wiring material 60 can be used.

In FIG. 7, the wiring material 50 connecting the cells is referred to as “wiring material 53”, the wiring material 50 connected to the crossover wiring material 61 is referred to as “wiring material 54”, and the wiring material 50 connected to the output wiring material 62 is used. It is referred to as "wiring material 55".

As illustrated in FIG. 7, the adjacent solar cells 20A and 20B and the adjacent solar cells 20C and 20D are directly connected by the wiring material 53. The inter-cell wiring material 60 does not exist between the cells, and for example, the wiring material 53 extends from the back side of the solar cell 20A to the back side of the solar cell 20B. One end side of the wiring material 53 is connected to the p-side contact electrode 39 of the solar cell 20A, and the other end side is connected to the n-side contact electrode 38 of the solar cell 20B. In this case, since it is not necessary to provide a gap for arranging the wiring material between the cells, the distance between the cells can be reduced to reduce the size of the solar cell module 10.

In the example shown in FIG. 7, the orientations of the solar cells 20A and 20B adjacent to each other in the first direction are different from each other by 180 °. Similarly, the solar cells 20C and 20D are arranged so that their orientations differ by 180 °. On the other hand, the solar cells 20A and 20D and the solar cells 20B and 20C adjacent to each other in the second direction are arranged in the same direction. In this case, in the solar cells 20 adjacent to each other in the first direction, the n-side contact electrode 38 and the p-side contact electrode 39 are arranged in the first direction, so that the solar cells 20 adjacent to each other in the first direction using the wiring material 53 are used. The n-side electrode layer 30 and the p-side electrode layer 31 can be connected.

That is, in the solar cells 20 adjacent to each other in the first direction, by arranging the solar cells 20 so that the n-side contact electrode 38 and the p-side contact electrode 39 are lined up in the first direction, one straight wiring material is used. Two solar cells 20 can be directly connected using the 53. In the example shown in FIG. 7, the n-side contact electrode 38 of the solar cell 20A and the output wiring material 62 are connected by the wiring material 55, and the p-side contact electrode 39 of the solar cell 20B and the cross wiring material 61 are wired. It is connected by a material 54. Further, the n-side contact electrode 38 of the solar cell 20C and the crossover wiring material 61 are connected by the wiring material 54, and the p-side contact electrode 39 of the solar cell 20D and the output wiring material 62 are connected by the wiring material 55. ..

FIG. 8 is a diagram showing an example of a connection pattern of the solar cell 20 divided into a plurality of subcells 41 and 42 and the wiring material 50 to the subcells 41 and 42. In FIG. 8, the wiring material 50 connecting the subcells in one solar cell 20 is referred to as “wiring material 56”, and the wiring material 50 connected to only one subcell in one solar cell 20 is referred to as “wiring material 50”. 57 ".

As illustrated in FIG. 8, the solar cell 20 may have at least one split portion 40 and may include a plurality of subcells 41, 42 arranged in the first direction. The subcells 41 and 42 are manufactured by dividing one solar cell 20, and there is a split portion 40 in which the cells are cut at the boundary portion of the adjacent subcells. By dividing one solar cell 20 into a plurality of subcells, it is possible to further improve the output characteristics while maintaining good productivity.

The solar cell 20 includes subcells 41 and 42 adjacent to each other in the first direction across the split portion 40. The subcells 41 and 42 are, for example, divided into substantially the same size, and the formation patterns of the semiconductor layers are the same as each other. The solar cell 20 may be divided into three or more subcells, and the sizes of the subcells may be different from each other. The split portion 40 is formed linearly along the second direction, and the subcells 41 and 42 are completely separated by the split portion 40.

The split portion 40 can be formed by irradiating a predetermined position of the solar cell 20 with a laser beam. As the laser, for example, a solid-state laser such as a YAG laser can be used. An example of the irradiation conditions of the laser light is that the wavelength of the second harmonic is 400 nm or more, the frequency is 1 to 50 kHz, the focusing diameter is 20 to 200 μm, and the output is 1 to 25 W. In this case, the split portion 40 having a width similar to that of the focused diameter of the laser beam can be formed. It is also possible to divide the solar cell 20 by a dicing process using a rotary blade, an etching process, or the like.

In the example shown in FIG. 8, the p-type regions 24 of the subcells 41 and 42 are formed on both sides of the split portion 40. That is, the p-type region 24 of the subcell 41 and the p-type region 24 of the subcell 42 are arranged adjacent to each other in the first direction with the split portion 40 interposed therebetween. Such a configuration can be produced, for example, by irradiating the central portion of the p-shaped region 24 of the solar cell 20 in the width direction with a laser beam along the second direction. The p-type region 24 to be separated may be formed wider than the other p-type regions 24.

In the subcells 41 and 42, p-shaped regions 24 are formed at both ends in the first direction. The n-type region 23 and the p-type region 24 are alternately formed in a stripe shape in the first direction, but in the subcells 41 and 41, the p-type region 24 is one more than the n-type region 23. That is, in the entire solar cell 20, two p-type regions 24 are formed more than the n-type region 23. Further, each p-type region 24 is formed wider than each n-type region 23. As described above, by dividing the solar cell 20 into a plurality of subcells 41 and 42 and forming the p-type region 24 in a larger area than the n-type region 23, the output characteristics are further improved.

In the example shown in FIG. 8, the n-side contact electrode 38 and the p-side contact electrode 39 are formed so as to be aligned in the first direction in the subcells 41 and 42. Specifically, the row of n-side contact electrodes 38 arranged in the first direction of the subcell 41 overlaps the row of p-side contact electrodes 39 arranged in the first direction of the subcell 42 in the first direction. It is preferable that the solar cell 20 before division has different contact electrode arrangements on one side and the other side of the solar cell 20 on which the split portion 40 is formed.

In this case, the n-side electrode layer 30 of the subcell 41 and the p-side electrode layer 31 of the subcell 42 can be connected by using one straight wiring material 56. The wiring material 57 is connected only to the p-side contact electrode 39 of the subcell 41 or only to the n-side contact electrode 38 of the subcell 42 in the solar cell 20 divided into the subcells 41 and 42.

FIG. 9 is a diagram showing an example of a connection pattern between the solar cells 20 divided into subcells 41 and 42. As illustrated in FIG. 9, the wiring material 57 is provided between the two solar cells 20 adjacent to each other in the first direction to the p-side contact electrode 39 of the subcell 41 and the n-side contact electrode 38 of the subcell 42. It is connected. As described above, the wiring material 56 is connected to the n-side contact electrode 38 of the subcell 41 and the p-side contact electrode 39 of the subcell 42 in one solar cell 20.

In the example shown in FIG. 9, the same cells are used for all the solar cells 20, and they are all arranged in the same direction. Since the arrangement of the contact electrodes in the subcells 41 and 42 is different by 180 °, even if the same cells are arranged in the same direction, the solar cells adjacent to each other in the first direction using one straight wiring material 57 are used. 20 can be connected to each other. Similar to the embodiment shown in FIG. 7, the wiring material 50 is provided with the wiring material 54 connected to the crossover wiring material 61 and the wiring material 55 connected to the output wiring material 62.

Further, as illustrated in FIG. 10, the solar cell 20 may include subcells 41 and 43 in which the formation patterns of the n-type region 23 and the p-type region 24 are different from each other. Unlike the subcell 41, the subcell 43 has n-type regions 23 at both ends in the first direction. Then, in the example shown in FIG. 10, the number of the n-type region 23 and the number of the p-type region 24 are the same in the entire solar cell 20. Such a configuration can be produced, for example, by irradiating the portion of the solar cell 20 where the insulating layer 27 is formed with laser light to form the split portion 40.

Also in this case, if the arrangement pattern of the contact electrodes in the subcells 41 and 43 is the same as in the case of the subcells 41 and 42, the subcells 41 and 42 constituting one solar cell 20 are connected by using the wiring material 56. can. Further, the solar cells 20 adjacent to each other in the first direction can be connected to each other by using the wiring material 57.

The connection structure of the wiring material 50 to the solar cell 20 will be described with reference to FIGS. 11 to 13. Although FIGS. 11 to 13 show the connection structure between the n-side contact electrode 38 and the wiring material 50, the same structure can be applied to the p-side contact electrode 39.

As illustrated in FIG. 11, the wiring material 50 may be fixed to the n-side contact electrode 38 by using a solder 70. The composition of the solder 70 is not particularly limited, and conventionally known materials can be applied. The wiring material 50 is fixed to the back surface of the solar cell 20 by the solder 70 existing between the n-side contact electrode 38 and the wiring material 50 and around the n-side contact electrode 38, and the n-side contact electrode 38 and the wiring material 50 are fixed. Is electrically connected.

When the solder 70 is used, there is a concern that the molten solder 70 may squeeze out from the n-side insulating layer 36 and flow into the groove 48 and come into contact with the p-side electrode layer 31. When the solder 70 flows into the groove 48, the n-side electrode layer 30 and the p-side electrode layer 31 may be electrically connected via the solder 70 and a short circuit may occur. Therefore, for example, the amount of the solder 70 used is adjusted so that the solder 70 does not flow into the groove 48. A resin layer (see FIG. 15 described later) may be provided so as to cover the groove 48 in the vicinity of the n-side contact electrode 38 to prevent the solder 70 from flowing into the groove 48.

As illustrated in FIG. 12, the wiring material 50 may be fixed to the back surface of the solar cell 20 by using an adhesive 71. In the example shown in FIG. 12, the wiring material 50 connected to the n-side contact electrode 38 is fixed to the back surface of the solar cell 20 by the adhesive 71 applied on the p-side insulating layer 37. A conventionally known resin adhesive can be used as the adhesive 71. One wiring material 50 is fixed to, for example, a plurality of p-side insulating layers 37 by using an adhesive 71.

On the other hand, the adhesive 71 does not exist between the n-side contact electrode 38 and the wiring material 50, and the n-side contact electrode 38 and the wiring material 50 are in direct contact with each other. An adhesive 71 may be provided between the contact electrode and the wiring material 50 as long as the electrical connection between the contact electrode and the wiring material 50 is not impaired. Alternatively, the contact electrode may be made of solder in the same manner as shown in FIG. 15 or the like described later.

As illustrated in FIG. 13, the n-side contact electrode 38 and the wiring material 50 may be connected by using the adhesive sheet 72 attached to one surface of the wiring material 50 facing the back surface of the solar cell 20. .. In this case, the wiring material 50 to which the adhesive sheet 72 is attached is arranged on the plurality of n-side contact electrodes 38 along the first direction, and the wiring material 50 is pressed against the n-side contact electrodes 38 by a simple operation. The wiring material 50 can be fixed to the back surface of the solar cell 20. The thickness of the adhesive sheet 72 interposed between the n-side contact electrode 38 and the wiring material 50 needs to be such that the electrical connection is not hindered. As the adhesive sheet 72, a sheet containing a conductive filler may be used.

14 and 15 are rear views showing the n-side contact electrode 38 and its vicinity in an enlarged manner, and show another example of the connection form of the wiring material 50 to the solar cell 20. Although the n-side contact electrode 38 is shown in FIGS. 14 and 15, the same structure can be applied to the p-side contact electrode 39.

In the example shown in FIGS. 14 and 15, the n-side contact electrode 38 is configured by the solder 73 filled in the openings 74 and 75 of the n-side insulating layer 36. The n-side insulating layer 36 is formed with openings 74, 75 that expose the n-side electrode layer 30. Then, the solder 73, which is filled in the openings 74 and 75 and bulges to the back side of the module from the n-side insulating layer 36, is connected to the n-side contact electrode 38 that electrically connects the n-side electrode layer 30 and the wiring material 50. Become.

In the example shown in FIG. 14, the n-side electrode layer 30 is exposed from the rear view rectangular opening 74 formed in the n-side insulating layer 36. The opening 74 is formed longer than the width of the wiring material 50 in the second direction. There is a concern that the molten solder 73 may flow into the groove 48 and come into contact with the p-side electrode layer 31 when the wiring material 50 is connected, but if the opening 74 is formed long in the second direction, excess solder 73 may be formed. It can be released in the second direction, and the flow of the solder 73 into the groove 48 can be suppressed more reliably. The length of the opening 74 in the second direction is, for example, 1.5 to 3 times the width of the wiring material 50. The wiring material 50 is preferably arranged on the n-side contact electrode 38 so that the central portion in the width direction overlaps the central portion in the second direction of the opening 74.

The form illustrated in FIG. 15 is different from the form illustrated in FIG. 14 in that the length of the opening 75 in the second direction is smaller than the width of the wiring material 50. In the example shown in FIG. 15, the resin layer 76 covering the groove 48 is formed so as to be aligned with the n-side contact electrode 38 made of the solder 73 in the first direction. The resin layer 76 is formed longer than the opening 75 in the second direction, and extends longer than both ends of the opening 75 in the second direction on both sides in the second direction. Further, the resin layer 76 is formed to be longer in the second direction than the width of the wiring material 50. In this case, since the molten solder 73 is blocked by the resin layer 76, the flow of the solder 73 into the groove 48 can be more reliably suppressed. An inorganic compound layer may be formed instead of the resin layer 76.

16 and 17 are views showing a cross-sectional structure of the n-side contact electrode 38 and its vicinity. Although the n-side contact electrode 38 is shown in FIGS. 16 and 17, the same structure can be applied to the p-side contact electrode 39.

As illustrated in FIG. 16, the n-side contact electrode 38 includes a contact portion 44 formed on the n-side insulating layer 36 and a conductive portion 45 connecting the contact portion 44 and the n-side electrode layer 30. As described above, the n-side insulating layer 36 is formed with an opening 46 that exposes the n-side electrode layer 30. The n-side contact electrode 38 can be formed, for example, by printing a metal paste such as silver paste on the portion where the opening 46 of the n-side insulating layer 36 is formed. Alternatively, the opening 46 may be filled with solder 73 to form the n-side contact electrode 38.

The contact portion 44 is a portion to which the wiring material 50 is connected, and bulges toward the back side of the module with respect to the n-side insulating layer 36. The conductive portion 45 is a portion filled in the opening 46. For example, the opening 46 is formed in a rectangular shape when viewed from the rear, and the conduction portion 45 is formed in a block shape by filling the entire opening 46. In the example shown in FIG. 16, the conductive portion 45 is connected over a wide range including the central portion of the contact portion 44. That is, the conductive portion 45 is formed on the n-side electrode layer 30 in an area similar to that of the contact portion 44.

As illustrated in FIG. 17, a plurality of conductive portions 45 may be formed with respect to one contact portion 44. The conductive portions 45 are formed at two locations separated in the second direction, and connect both ends of the contact portion 44 in the second direction to the n-side electrode layer 30. In this case, the amount of silver paste used can be reduced while ensuring good connectivity between the contact electrode and the wiring material 50. The n-side insulating layer 36 is formed with small openings 77 that penetrate the insulating layer in the thickness direction at two locations separated in the second direction. The n-side contact electrode 38 shown in FIG. 17 is formed, for example, by printing a silver paste on the n-side insulating layer 36 over the two openings 77.

In the example shown in FIG. 17, it is preferable that the total length of the plurality of conductive portions 45 in the second direction is half or less of the length of the contact portion 44 in the second direction, which is short as long as the resistance loss does not matter. For example, the length of the contact portion 44 in the second direction is longer than the width of the wiring material 50, and the total length of the plurality of conduction portions 45 in the second direction is shorter than the width of the wiring material 50. Similarly, the total length of the conductive portions 45 in the first direction is preferably shorter than the length of the contact portion 44 in the first direction.

In the example shown in FIG. 16, the wiring material 50 is arranged at the center of the n-side contact electrode 38 in the second direction, but as shown in FIG. 17, the n-side contact electrode 38 is biased to one side in the second direction. The wiring material 50 may be arranged.

When a part of the plurality of solar cell 20 constituting the solar cell module 10 is damaged, it is assumed that the wiring material 50 is cut and the damaged cell is replaced. In this case, on some contact electrodes. Will have two wiring materials 50 attached. As shown in FIG. 17, if the wiring material 50 is biased to one side of the n-side contact electrode 38, the n-side contact electrode 38 is arranged so that the additional wiring material 50 does not overlap with the existing wiring material 50. It is easy to place on the other side of the. In other words, the contact portion 44 shown in FIG. 17 is formed with a length that allows the two wiring materials 50 to be arranged side by side in the second direction.

FIG. 18 is a diagram for explaining an example of a method for manufacturing the solar cell module 10. Conventionally known methods can be applied to the formation of the surface texture of the substrate 22, the film formation of the semiconductor layer, the etching, and the like.

As illustrated in FIG. 18, the solar cell 20 has an n-type semiconductor layer 25 and a p-type semiconductor layer 26 formed on one main surface of a substrate 22 such as a single crystal silicon wafer, and then has an electrode layer and insulation. Manufactured by forming layers and contact electrodes. The n-type semiconductor layer 25 and the p-type semiconductor layer 26 are alternately formed in the first direction of one main surface of the substrate 22, and form the n-type region 23 and the p-type region 24 in a striped manner. The widthwise both ends of the p-type semiconductor layer 26 formed in a strip shape overlap with each other on the widthwise both ends of the n-type semiconductor layer 25 via the insulating layer 27, and are placed on one main surface of the substrate 22. Two types of semiconductor layers are formed without gaps.

One main surface of the substrate 22 on which the n-type semiconductor layer 25 and the p-type semiconductor layer 26 are formed is the back surface of the solar cell 20 (photoelectric conversion unit 21). Further, the passivation layer 29 and the protective layer 28 are formed in this order on substantially the entire area of the light receiving surface of the photoelectric conversion unit 21. An electrode layer 80 that covers the n-type semiconductor layer 25 and the p-type semiconductor layer 26 is formed on the back surface of the photoelectric conversion unit 21. The electrode layer 80 preferably has a multi-layer structure including a transparent conductive layer and a metal layer, and can be formed into a film by a conventionally known method such as sputtering. The electrode layer 80 covers the entire n-type semiconductor layer 25 and the p-type semiconductor layer 26, and is formed on substantially the entire back surface of the photoelectric conversion unit 21.

Next, the n-side insulating layer 36 and the p-side insulating layer 37 are formed so as to cover the entire electrode layer 80 excluding the portion where the groove 48 is formed. That is, the insulating layer may be formed in a pattern in which a groove 49 for separating the n-side insulating layer 36 and the p-side insulating layer 37 is formed in advance. Alternatively, after forming an insulating layer covering the entire area of the electrode layer 80, as described above, a part of the insulating layer is irradiated with laser light to form a groove 49, and the insulating layer is formed with the n-side insulating layer 36 and p. It may be separated into the side insulating layer 37. Subsequently, using the n-side insulating layer 36 and the p-side insulating layer 37 as masks, the portion exposed from the groove 49 of the electrode layer 80 is removed by etching to form the groove 48, and the electrode layer 80 is combined with the n-side electrode layer 30. It is separated into the p-side electrode layer 31.

Next, openings 46 and 47 penetrating the insulating layer are formed, respectively. A plurality of openings 46, 47 are formed at predetermined intervals in the second direction. The openings 46 and 47 are arranged so that the openings 46 formed in each of the n-side insulating layers 36 are arranged in the first direction and the openings 47 formed in each of the p-side insulating layers 37 are also arranged in the first direction. It is formed. The openings 46 and 47 are formed so as not to overlap in the first direction.

Subsequently, a metal paste such as silver paste is printed on the portions of the insulating layers where the openings 46 and 47 are formed and fired to form the n-side contact electrode 38 and the p-side contact electrode 39. In this way, the solar cell 20 is manufactured. The solar cell 20 can also be divided into a plurality of subcells by, for example, irradiating the laser beam along the second direction. A string is produced by attaching a wiring material 50 to each contact electrode and electrically connecting a plurality of solar cell 20s. The solar cell module 10 is manufactured by sandwiching and laminating a string between two protective members via a sealing material sheet.

19 to 21 are diagrams showing a modified example of two types of semiconductor layer forming patterns and an example of cell-to-cell connection in each modified example. In the above-described embodiment, the n-type region 23 and the p-type region 24 are formed in a striped shape along the second direction of the back surface of the substrate 22, but as illustrated in FIGS. 19 to 21, photoelectric conversion is performed. On the back surface of the portion 21, a second p-shaped region 78 extending in the first direction may be formed on at least one of both ends in the second direction orthogonal to the first direction.

In the example shown in FIG. 19, two p-shaped regions 78 extending in the first direction are formed at both ends of the back surface of the substrate 22 in the second direction. The p-type region 78 is connected to the p-type region 24 arranged at both ends in the first direction. Then, on the back surface of the substrate 22, a p-shaped region is formed in an annular shape along the peripheral edge portion. Further, all of the p-type region 24 may be connected to the p-type region 78, and the p-type region may be formed as one continuous region. On the other hand, the n-type region 23 is separated into a plurality by the p-type region.

In the example shown in FIG. 19, in the solar cells 20A and 20B adjacent to each other in the first direction, the plurality of n-side contact electrodes 38 and the plurality of p-side contact electrodes 39 are arranged in the first direction, respectively. Therefore, the inter-cell wiring material 60 is arranged between the solar cell 20A and 20B. The wiring material 50 connected to the p-side contact electrode 39 of the solar cell 20A and the wiring material 50 connected to the n-side contact electrode 38 of the solar cell 20B are connected to the cell-to-cell wiring material 60, respectively. .. A plurality of p-side contact electrodes 39 arranged in the first direction are formed on the p-type region 78.

The embodiment illustrated in FIG. 20 is different from the embodiment illustrated in FIG. 19 in that the second p-type region 78 is formed only at one end in the second direction of the solar cells 20A and 20B. In the solar cells 20A and 20B, the p-type regions 78 are formed side by side in the first direction. Further, each p-type region 24 is connected to the p-type region 78, and the p-type region is formed in a comb-teeth shape as a whole. Also in this case, the cell-to-cell connection form similar to the form illustrated in FIG. 19 is provided.

The form illustrated in FIG. 21 is different from the form illustrated in FIG. 20 in that the second p-type region 78 is formed in the solar cells 20A and 20B so as to be located on the opposite side in the second direction. .. The solar cell 20B has a p-type region 78 formed only at one end in the second direction, and the solar cell 20A has a p-type region 78 formed only at the other end in the second direction. In this case, the same cells can be used for the solar cells 20A and 20B, and the cells may be arranged so that the orientations of the cells differ by 180 °.

In the example shown in FIG. 21, in the solar cells 20A and 20B adjacent to each other in the first direction, the n-side contact electrode 38 and the p-side contact electrode 39 are arranged in the first direction. Therefore, the solar cells 20A and 20B can be connected by using one straight wiring material 50 without using the inter-cell wiring material 60.

22 to 24 are views showing a modified example of the contact electrode. The cross-sectional view on the left side of the paper in FIG. 22 shows the cross-sectional view of the circled portion in the rear view. Further, although the n-side contact electrode 38 is shown in FIG. 23, the same structure can be applied to the p-side contact electrode 39.

The example shown in FIG. 22 differs from the above-described embodiment in that the n-side contact electrodes 38 are formed at a ratio of two or more per wiring material along each longitudinal direction of the n-type region 23. .. Similarly, the p-side contact electrode 39 is formed at a ratio of two or more per wiring material along the longitudinal direction of each of the p-shaped regions 24. In the example shown in FIG. 22, four contact electrodes are formed per wiring material. In this case, the number of contact electrodes formed along the longitudinal direction of each semiconductor region is twice the number of wiring materials 50 arranged on the back surface of the solar cell 20.

The wiring material 50 is arranged along the first direction, but as shown in FIG. 22, it is assumed that the wiring material 50 is arranged so as to deviate from the first direction. In such a case, in order to secure the connection between the wiring material 50 and the contact electrode, for example, it is necessary to form the contact electrode long in the second direction. However, there is a problem that the amount of silver paste used increases when the contact electrode is lengthened. Therefore, as illustrated in FIG. 22, it is preferable to disperse and arrange a plurality of contact electrodes in a second direction, which is larger than the number of wiring materials 50. In this case, it is possible to more reliably secure the connection between the wiring material 50 and the contact electrode while suppressing the amount of silver paste used.

In the example shown in FIG. 22, a plurality of n-side contact electrodes 38 are linearly arranged side by side in the longitudinal direction of each n-type region 23, four for each wiring material. In a set of n-side contact electrodes 38 (four in the example shown in FIG. 22), the distance between the electrodes in the second direction is preferably the same as or smaller than the width of the wiring material 50. In this case, the connection between the wiring material 50 and the contact electrode can be secured more reliably. Further, from the viewpoint of suppressing the amount of silver paste used, it is preferable that the length of each n-side contact electrode 38 in the second direction is shorter than the width of the wiring material 50.

In the set of n-side contact electrodes 38, the relationship between the width and spacing of each electrode and the width of the wiring material 50 satisfies, for example, the following conditions.
Electrode width x 2 + Electrode spacing> Wiring material width> Electrode width In this case, when the wiring material 50 is crimped to the cell, the contact between the wiring material 50 and the insulating layer is suppressed, and dielectric breakdown due to the influence of heat during crimping is prevented. be able to.

Similarly, for the p-side contact electrode 39, in a set of electrodes, the distance between the electrodes in the second direction is the same as or smaller than the width of the wiring material 50, and the length of each electrode in the second direction is the wiring material 50. It is preferably shorter than the width of. Further, the contact electrode may have a tapered shape that tapers toward the tip end side. For example, if the wiring material 50 is a round material, the contact area with the wiring material 50 can be increased by forming the tip of the p-side contact electrode 39 in a tapered shape.

As illustrated in FIG. 23, a plurality of sets of n-side contact electrodes 38 formed corresponding to each of the wiring materials 50 may have different heights from each other. When the wiring material 50 is a round material, the electrodes located at both ends of the second direction may be formed high and the electrodes located at the center of the second direction may be formed low in the set of n-side contact electrodes 38. .. In this case, the plurality of n-side contact electrodes 38 can easily come into contact with each other along the surface of the wiring material 50, and the contact area between the wiring material 50 and the electrodes can be expanded. In the example shown in FIG. 23, in the set of electrodes, the height of the electrodes gradually decreases from both ends in the second direction toward the center. The length of each electrode in the second direction is shorter than the width of the wiring material 50, and the distance between the electrodes in the second direction is small.

As illustrated in FIG. 24, the plurality of n-side contact electrodes 38 may be alternately formed on one end side and the other end side in the first direction along each of the n-type regions 23. That is, in a set of n-side contact electrodes 38, each electrode is directed from one side in the second direction to the other side, and the n-type region 23 (n-side electrode 30) has one end side, the other end side, and one end in the first direction. It is formed in a staggered pattern in the order of the side and the other end side. In this case, even if the wiring material 50 is arranged so as to be displaced, the connection between the wiring material 50 and the contact electrode can be more reliably secured. Further, the pressure when the wiring material 50 is crimped to the cell can be dispersed.

In the example shown in FIG. 24, the p-side contact electrode 39 is similarly formed alternately on one end side and the other end side in the first direction along each of the p-shaped regions 24. Since the width of the p-type region 24> the width of the n-type region 23, the distance between the contact electrodes formed in a staggered manner in the first direction can be p-side contact electrode 39> n-type contact electrode 38.

As described above, according to the solar cell module 10 having the above-described configuration, since the plurality of wiring materials 50 are connected to the contact electrodes on the semiconductor region formed in a striped shape, the current collection efficiency is high and power generation is performed. It is possible to efficiently take out the generated electricity. In addition, the invalid area of the solar cell 20 that does not contribute to power generation can be reduced. Therefore, the solar cell module 10 has excellent output characteristics. Further, since the entire area on the electrode layer is covered with the insulating layer, the occurrence of a short circuit can be suppressed more reliably, and when Cu is contained in the electrode layer, Cu ions are diffused into the encapsulant 13. The occurrence of copper damage can be suppressed.

Further, in the adjacent solar cells 20A and 20B, the n-type contact electrode 38 of the solar cell 20A and the p-type contact electrode 39 of the solar cell 20B are arranged side by side in the first direction, whereby the inter-cell wiring material 60 is arranged. The solar cells 20A and 20B can be connected without using. In this case, since the distance between cells can be reduced, for example, the size of the solar cell module 10 can be reduced. Further, by using the solar cell 20 divided into a plurality of subcells, the output characteristics can be further improved.

The above-described embodiment can be appropriately redesigned as long as the object of the present disclosure is not impaired. For example, the configuration in which a plurality of contact electrodes are dispersedly arranged on one wiring material has been described as being applied to both the n-side and p-side contact electrodes, but it may be applied to only one of them. good.

10 Solar cell module, 11 1st protective member, 12 2nd protective member, 13 Encapsulant, 14 Terminal box, 20 Solar cell, 21 Photoelectric converter, 22 Substrate, 23 n type area, 24,78 p type area , 25 n-type semiconductor layer, 26 p-type semiconductor layer, 27 insulating layer, 28 protective layer, 29 passage layer, 30 n side electrode layer, 31 p side electrode layer, 32, 34 transparent conductive layer, 33, 35 metal layer, 36 n side insulating layer, 37 p side insulating layer, 38 n side contact electrode, 39 p side contact electrode, 40 split part, 41, 42, 43 subcell, 44 contact part, 45 conductive part, 46, 47 opening, 48 , 49 grooves, 50, 51, 52, 53, 54, 55, 56, 57 wiring material, 60 cell-to-cell wiring material, 61 crossing wiring material, 62 output wiring material, 70, 73 solder, 71 adhesive, 72 adhesive Sheet, 74,75,77 openings, 76 resin layer, 80 electrode layer

Claims (9)

A solar cell module comprising a plurality of solar cells and a plurality of wiring materials connected to at least one of the plurality of solar cells.
Each of the plurality of solar cell cells
A photoelectric conversion unit in which n-type regions and p-type regions are alternately formed in the first direction on the main surface, and
The n-side electrode layer formed on the n-type region and
The p-side electrode layer formed on the p-shaped region and
The n-side insulating layer formed on the n-side electrode layer and
The p-side insulating layer formed on the p-side electrode layer and
The n-side contact electrode connected to the n-side electrode layer through the opening of the n-side insulating layer, and the n-side contact electrode.
The p-side contact electrode connected to the p-side electrode layer through the opening of the p-side insulating layer, and the p-side contact electrode.
Including
The n-side insulating layer covers the entire area on the n-side electrode layer except the portion where the n-side contact electrode is formed.
The p-side insulating layer covers the entire area on the p-side electrode layer except the portion where the p-side contact electrode is formed.
A solar cell module in which each of the plurality of wiring materials extends in the first direction and is connected to at least one of the n-side contact electrode and the p-side contact electrode. The plurality of solar cell cells include a first solar cell module and a second solar cell module adjacent to each other.
The first aspect of claim 1, wherein at least one of the plurality of wiring materials is connected to the n-side contact electrode of the first solar cell and the p-side contact electrode of the second solar cell, respectively. Solar cell module. The solar cell module according to claim 1 or 2, wherein the plurality of solar cells have at least one split portion and include the plurality of subcells arranged in the first direction. The plurality of subcells include a first subcell and a second subcell that are adjacent to each other across the split portion.
The solar cell module according to claim 3, wherein at least one of the plurality of wiring materials is connected to the n-side contact electrode of the first subcell and the p-side contact electrode of the second subcell. .. The solar cell module according to claim 4, wherein the p-shaped region of the first subcell and the second subcell is formed on both sides of the split portion. A second p-shaped region extending in the first direction is formed on at least one of both ends of the second direction orthogonal to the first direction on the main surface of the photoelectric conversion unit. The solar cell module according to any one of 1 to 5. A plurality of the n-side contact electrodes are formed at a ratio of two or more per one of the plurality of wiring materials along the longitudinal direction of each of the n-shaped regions.
One of claims 1 to 6, wherein a plurality of the p-side contact electrodes are formed at a ratio of two or more per one of the plurality of wiring materials along the longitudinal direction of each of the p-shaped regions. The solar cell module described in. The plurality of n-side contact electrodes are alternately formed on one end side and the other end side in the first direction along the longitudinal direction of each of the n-type regions.
The solar cell module according to claim 7, wherein the plurality of p-side contact electrodes are alternately formed on one end side and the other end side in the first direction along the longitudinal direction of each of the p-shaped regions. .. The n-side contact electrode is composed of solder filled in the opening of the n-side insulating layer.
The p-side contact electrode is composed of solder filled in the opening of the p-side insulating layer.
The solar cell module according to any one of claims 1 to 8, wherein each of the openings is formed longer than the width of the plurality of wiring materials.

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