JP2011134999A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency solar cell module with a simple structure. <P>SOLUTION: The solar cell module includes a plurality of solar cell elements 10 containing: a semiconductor substrate 1 having a first surface 1F and a second surface 1S corresponding to the backside of the first surface 1F; a first electrode 4 provided to the second surface 1S; and a second electrode 5 which is provided to the second surface 1S and has polarity different from the first electrode 4. The solar cell module is constituted by electrically connecting the first electrode 4 of one solar cell element 10 and the second electrode 5 of the other solar cell element 10. The second electrode 5 includes a collector 5b, and the collector 5b has translucency. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solar cell module.

  One type of solar cell element is a back contact type solar cell element (see, for example, Patent Documents 1 and 2).

  A conventional back-contact solar cell element includes a semiconductor substrate having one conductivity type, a semiconductor layer having a conductivity type opposite to that of the semiconductor substrate, a first electrode, and a first electrode. And a second electrode having different polarities. The semiconductor substrate includes a plurality of through holes penetrating between the light receiving surface and the back surface. The reverse conductivity type semiconductor layer is provided on the light receiving surface of the semiconductor substrate, the second semiconductor layer provided on the surface of the through hole of the semiconductor substrate, and the back surface side of the semiconductor substrate. It consists of a third semiconductor layer. The first electrode is formed on the light-receiving surface electrode portion formed on the light-receiving surface side of the semiconductor substrate, the through-hole electrode portion formed in the through-hole, and the through-hole electrode portion on the back surface of the semiconductor substrate. It consists of a bus bar electrode part. The light-receiving surface electrode part, the through-hole electrode part, and the bus bar electrode part are electrically connected to each other. The second electrode is formed on a portion of the back surface of the semiconductor substrate where the third semiconductor layer is not formed.

  In addition, as another back contact type solar cell element, there is one in which a first electrode and a second electrode are formed on a back surface of a semiconductor substrate in a comb shape.

International Publication No. 2008/078741 JP 2006-523025 A

  However, while the above-described solar cell element and the solar cell module using the solar cell element are expected to further spread, it is important to improve the conversion efficiency of sunlight with a simple configuration. In order to improve the conversion efficiency, it is important that more light is absorbed by the solar cell element.

  The present invention has been made based on the above problems, and an object thereof is to provide a highly efficient solar cell module with a simple configuration.

  The solar cell module of the present invention includes a semiconductor substrate having a first surface and a second surface corresponding to the back surface of the first surface, a first electrode provided on the second surface, and the second surface. Provided with a plurality of solar cell elements having a second electrode having a polarity different from that of the first electrode. The solar cell module of the present invention is formed by electrically connecting the first electrode of one of the solar cell elements and the second electrode of the other solar cell element. Furthermore, in the solar cell module of the present invention, the second electrode includes a current collector having translucency.

  Conventionally, the solar cell module of the present invention has a solar cell element (semiconductor) as opposed to a back-contact type solar cell element that focuses on light reception from the surface (first surface) side of the solar cell element (semiconductor substrate). Since the current collecting part of the second electrode provided on the back surface (second surface) of the substrate) has translucency, it is possible to capture a large amount of light from the back surface side of the solar cell element 1 as well. This can contribute to improvement of output characteristics.

It is the top view seen from the 1st surface side which shows the structure of 1st Embodiment of the solar cell element which comprises the solar cell module which concerns on embodiment of this invention. It is the top view seen from the 2nd surface side which shows the structure of 1st Embodiment of the solar cell element which comprises the solar cell module which concerns on embodiment of this invention. It is sectional drawing seen from the cross section AA of FIG. It is the top view seen from the 2nd surface side which shows the other structure of 1st Embodiment of the solar cell element which comprises the solar cell module which concerns on embodiment of this invention. It is the top view seen from the 1st surface side which shows the structure of 2nd Embodiment of the solar cell element which comprises the solar cell module which concerns on embodiment of this invention. It is the top view seen from the 2nd surface side which shows the structure of 2nd Embodiment of the solar cell element which comprises the solar cell module which concerns on embodiment of this invention. It is sectional drawing seen from the cross section BB of FIG. The structure of the solar cell module which concerns on embodiment of this invention is shown typically, (a) is a side view, (b) is a top view. It is a figure which shows the mode of the connection by the wiring material of solar cell elements in the solar cell module which concerns on embodiment of this invention. FIG. 10 is an enlarged plan view of a portion C in FIG. 9. It is a figure which shows the mode of the connection by the wiring material of solar cell elements in the solar cell module which concerns on embodiment of this invention. FIG. 12 is an enlarged plan view of a part D in FIG. 11. It is an enlarged plan view which shows the modification of the part C of FIG. It is a top view which shows the insulating sheet which comprises the solar cell module which concerns on embodiment of this invention. It is an expansion schematic diagram which shows the insulating sheet which comprises the solar cell module which concerns on embodiment of this invention. It is an expansion schematic diagram which shows the insulating sheet which comprises the solar cell module which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, an embodiment of a solar cell element constituting a part of a solar cell module according to an embodiment of the present invention will be described.

≪Structure of solar cell element≫
The solar cell element 10a according to the first embodiment includes a semiconductor substrate 1 exhibiting one conductivity type, a reverse conductivity type layer 2 having a conductivity type different from that of the semiconductor substrate 1, a through-hole 3, and a first electrode 4. And a second electrode 5.

  1 to 3, the solar cell element 10a includes a first surface 1F (upper surface side in FIG. 3) and a second surface 1S on the back side of the first surface 1F (lower surface side in FIG. 3). ) Including a semiconductor substrate 1. In the solar cell element 10a, the first surface 1F is the front surface (for convenience of explanation, the first surface 1F may be referred to as the front surface of the semiconductor substrate 1 and the second surface 1S may be referred to as the back surface of the semiconductor substrate 1). ).

  As the semiconductor substrate 1, for example, a crystalline silicon substrate such as a single crystal silicon substrate or a polycrystalline silicon substrate having a predetermined dopant element (impurity for conductivity control) and exhibiting one conductivity type (for example, p-type) is used. Used. The thickness of the semiconductor substrate 1 is more preferably, for example, 250 μm or less, and further preferably 150 μm or less. The shape of the semiconductor substrate 1 is not particularly limited, but a rectangular shape as in the present embodiment is preferable from the viewpoint of the manufacturing method.

  In the present embodiment, an example in which a crystalline silicon substrate exhibiting a p-type conductivity is used as the semiconductor substrate 1 will be described. When the semiconductor substrate 1 made of a crystalline silicon substrate is p-type, it is preferable to use, for example, boron or gallium as the dopant element.

  On the first surface 1F side of the semiconductor substrate 1, as shown in FIG. 3, a large number of solar beams are absorbed into the semiconductor substrate 1 by reducing the reflection of incident light on the first surface 1 F. A texture structure (concavo-convex structure) 1a composed of the fine protrusions 1b is formed. Note that the texture structure 1a is not an essential component in the present embodiment, and may be formed as necessary.

  In addition, as shown in FIG. 3, the semiconductor substrate 1 has a plurality of through holes 3 between the first surface 1F and the second surface 1S. As will be described later, the second reverse conductivity type layer 2b is formed on the inner surface of the through hole 3. The inner surface of the through hole 3 refers to the inner wall surface of the part where the through hole 3 of the semiconductor substrate 1 is formed. In addition, a conduction portion 4 b of the first electrode 4 is formed inside the through hole 3. The through holes 3 are preferably formed at a constant pitch in the range of 50 μm to 300 μm in diameter.

  The reverse conductivity type layer 2 is a layer having a conductivity type opposite to that of the semiconductor substrate 1. The reverse conductivity type layer 2 includes a first reverse conductivity type layer 2a formed on the first surface 1F side of the semiconductor substrate 1, a second reverse conductivity type layer 2b formed on the inner surface of the through hole 3, a semiconductor And a third reverse conductivity type layer 2c formed on the second surface 1S side of the substrate 1. If a silicon substrate exhibiting a p-type conductivity is used as the semiconductor substrate 1, the reverse conductivity type layer 2 is formed to exhibit an n-type conductivity. On the other hand, when a silicon substrate having n-type conductivity is used as the semiconductor substrate 1, the reverse conductivity type layer 2 is formed to exhibit p-type conductivity.

The first reverse conductivity type layer 2a is preferably formed as an n ⁺ type having a sheet resistance of about 60 to 300Ω / □. By setting it as this range, increase in surface recombination and increase in surface resistance on the first surface 1F can be suppressed. The first reverse conductivity type layer 2a is preferably formed on the first surface 1F of the semiconductor substrate 1 to a depth of about 0.2 μm to 0.5 μm. The third opposite conductivity type layer 2c is formed in the second electrode 1S of the semiconductor substrate 1 in the formation region of the first electrode 4 and its peripheral part. By having the reverse conductivity type layer 2, a pn junction is formed between the reverse conductivity type layer 2 and the bulk region of the semiconductor substrate 1 (a region where the reverse conductivity type layer 2 is not formed) in the solar cell element 10 a. Is done.

  The solar cell element 10 a has a semiconductor layer 6 on the second surface 1S of the semiconductor substrate 1. The semiconductor layer 6 is for the purpose of forming an internal electric field inside the solar cell element 10a in order to suppress a decrease in power generation efficiency due to carrier recombination in the vicinity of the second surface 1S of the semiconductor substrate 1. It is a layer provided (for the purpose of obtaining the so-called BSF effect). The semiconductor layer 6 is formed on the second surface 1S side of the semiconductor substrate 1 in a region where the third reverse conductivity type layer 2c and the first electrode 4 are not provided (non-forming region). More specifically, the semiconductor layer 6 is formed on the second surface 1S side so as not to contact the third reverse conductivity type layer 2c and the first electrode 4. Further, a pn isolation region is provided between the third reverse conductivity type layer 2c and the semiconductor layer 6 and at the peripheral portion of the second surface 1S of the semiconductor substrate 1, and the semiconductor substrate is provided in such a pn isolation region. There is one bulk region.

The semiconductor layer 6 has the same conductivity type as the semiconductor substrate 1, but has a concentration higher than the concentration of the dopant contained in the semiconductor substrate 1. Here, “high concentration” means that the dopant element is present at a concentration higher than the concentration of the dopant element doped to exhibit one conductivity type in the semiconductor substrate 1. If the semiconductor substrate 1 exhibits p-type, the semiconductor layer 6 has a concentration of these dopant elements of 1 × 10 ^{18 to} 5, for example, by diffusing a dopant element such as boron or aluminum into the second surface 1S. It is preferably formed so as to be about × 10 ²¹ atoms / cm ³ . As a result, the semiconductor layer 6 exhibits a p ⁺ type conductivity type containing a dopant at a higher concentration than the p type conductivity type exhibited by the semiconductor substrate 1. Ohmic contact is realized between the two.

  As shown in FIG. 1, the solar cell element 10 a has an antireflection film 7 on the first surface 1 </ b> F side of the semiconductor substrate 1. The antireflection film 7 has a role of reducing the reflection of incident light on the surface (first surface 1F) of the semiconductor substrate 1, and is formed on the first reverse conductivity type layer 2a. The antireflection film 7 is preferably formed of a silicon nitride film or an oxide material film. The thickness of the antireflection film 7 is set to a value that realizes a non-reflection condition for incident light, although a suitable value varies depending on the constituent material. For example, when a silicon substrate is used as the semiconductor substrate 1, the antireflection film 7 may be formed to a thickness of about 500 to 1200 mm with a material having a refractive index of about 1.8 to 2.3. The provision of the antireflection film 7 is not an essential component in the present embodiment, and may be formed as necessary.

As shown in FIG. 3, the solar cell element 10 a has a passivation film 8 on the second surface 1S side of the semiconductor substrate 1. The passivation film 8 has a role of reducing carrier recombination on the back surface (second surface 1S) of the semiconductor substrate 1. Examples of the passivation film 8 include Si nitride films such as silicon nitride (Si ₃ N ₄ ) and amorphous Si nitride films (a-SiNx), silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and titanium oxide ( TiO ₂ ) or the like can be used. The thickness of the passivation film may be about 100 to 2000 mm. The provision of the passivation film 8 is not an essential component in the present embodiment, and may be formed as necessary.

  As shown in FIG. 3, the first electrode 4 has a main electrode portion 4a formed on the first surface 1F of the semiconductor substrate 1 and a through hole 3 electrically connected to the main electrode portion 4a. It has a conductive part 4b provided and a first output extraction part 4c formed on the second surface 1S and connected to the conductive part 4b. The main electrode portion 4a has a function of collecting carriers generated on the first surface 1F side. The conduction part 4b has a function of guiding the carriers collected by the main electrode part 4a to the first output extraction part 4c provided on the second surface 1S side. The 1st output extraction part 4c has a function as a wiring connection part connected with the wiring material which electrically connects adjacent solar cell elements.

  In the present embodiment, the plurality of conductive portions 4b are arranged in a predetermined direction. In this solar cell element 10a, as shown in FIG. 1, a plurality of conducting portions 4b are arranged in a plurality of rows (three rows in FIG. 1) in a direction parallel to the reference side BS of the first surface 1F of the semiconductor substrate 1. ). The reference side BS is a side that is parallel to the arrangement direction when the solar cell module 20 is formed by arranging a plurality of solar cell elements 10a. Hereinafter, a direction along the reference side BS (a direction parallel to the reference side BS) may be referred to as an arrangement direction. In the solar cell element 10a, the conducting portions 4b are provided linearly along the arrangement direction, and are provided at approximately equal intervals. In this specification, it is needless to say that “parallel” should not be strictly understood as in mathematical definition.

  The main electrode portion 4a of the first electrode 4 has a plurality of linear patterns (a plurality of linear conductors) connecting the conductive portions 4b belonging to different columns on the first surface 1F of the semiconductor substrate 1. ). In the present embodiment, the number of linear conductors is the same as the number of conductive portions 4b belonging to one column arranged in one direction. The linear conductor of the main electrode portion 4a is preferably formed to have a line width of about 50 to 100 μm. In addition, it is preferable from the viewpoint of improving the aesthetic appearance that the plurality of linear conductors as described above are formed so as to have substantially equal intervals, for example, about 1 to 3 mm.

  Further, the main electrode portion 4 a may have a circular pattern that covers the through hole 3 and is larger than the diameter of the through hole 3. According to such a form, it becomes possible to connect with the conduction | electrical_connection part 4b even if the formation position of the main electrode part 4a shifts | deviates a little. In addition, the pattern of the main electrode part 4a is not restricted to what was shown in FIG. 1, A various pattern can be formed.

  As shown in FIG. 2, the first electrode 4 has a first output extraction portion 4c on the second surface 1S of the semiconductor substrate 1 at a position directly below the plurality of conduction portions 4b (through holes 3). is doing. The first output extraction portion 4c has a long shape having a longitudinal direction in the arrangement direction of the conducting portions 4b (the direction along the reference side BS). The first output extraction portion 4c is formed in a plurality of rows (three rows in FIG. 2) corresponding to the arrangement of the conducting portions 4b. The width | variety of the 1st output extraction part 4c should just be the same as the width | variety of the wiring material mentioned later or larger than it, for example, is set to 1.5-4 mm.

  On the other hand, the second electrode 5 has a polarity different from that of the first electrode 4 and is disposed on the second surface 1S of the semiconductor substrate 1 so as to be insulated from the first electrode 4. Yes. Therefore, for example, the second electrode 5 is disposed on the second surface 1S of the semiconductor substrate 1 so as to be separated from the first electrode 4. As shown in FIG. 2, the second electrode 5 has a second output extraction portion 5a and a current collecting portion 5b.

The current collector 5b is formed on substantially the entire surface of the semiconductor substrate 1 on the second surface 1S side where the third reverse conductivity type layer 2c and the first electrode 4 are not provided (non-formation region). The carriers generated on the second surface 1S side are collected. Here, “substantially the entire surface” means that when the second surface 1S of the semiconductor substrate 1 is viewed in plan, the current collector 5b is formed in 50% or more of the entire region of the second surface 1S. . As thickness of the current collection part 5b, it forms in about 0.1-3 micrometers, for example. In FIG. 3, the current collector 5 b is formed on the passivation film 8, and a contact portion between the semiconductor substrate 1 and the current collector 5 b is formed in the opening of the passivation film 8. In addition, it is preferable that the semiconductor layer 6 is formed on the semiconductor substrate 1 side of the contact portion. Further, the current collector 5b has translucency. Here, the translucency refers to a property that allows light to pass therethrough, that is, sunlight in this embodiment. In addition, it is not necessary to transmit the light of all the wavelengths among sunlight, and the case where the light of the one part wavelength is transmitted is also included that sunlight can permeate | transmit. In particular, the transmittance is preferably 70% or more with respect to light in the wavelength range of 400 to 1100 nm. Such a current collector 5b is made of, for example, an oxide-based transparent conductive material such as SnO ₂ , ITO, or ZnO. What is necessary is just to form with a film | membrane.

  The 2nd output extraction part 5a has a role as a wiring connection part connected with the wiring material which electrically connects adjacent solar cell elements. Moreover, it is preferable that the 2nd output extraction part 5a is comprised so that at least one part may overlap with the current collection part 5b. In FIG. 2, a plurality of second output extraction portions 5a are formed in a direction along the reference side BS, and are provided at both ends of the first output extraction portions 4c in one row in parallel with the first output extraction portions 4c. It has been. The magnitude | size of the 2nd output extraction part 5a is a magnitude | size which can connect a wiring material, for example, is set with 4-10 mm. Moreover, what is necessary is just to form the 2nd output extraction part 5a with metals, such as silver and copper, for example.

  As described above, the solar cell element 10a according to the present embodiment has the above-described configuration, and the current collector 5b of the second electrode 5 has translucency. Therefore, the first surface 1F side of the semiconductor substrate 1 is used. In addition to receiving light not only from the second surface 1S side, it is possible to contribute to the improvement of the output characteristics of the solar cell element. In the configuration shown in FIG. 2, the second output extraction portion 5a is provided by providing the second output extraction portion 5a in each of the current collectors 5b divided into a plurality of regions by the first output extraction portion 4c. It is possible to shorten the moving distance of the carrier until it reaches, and to suppress the resistance loss. In the present embodiment, if the antireflection film as described above is provided on the current collector 5b, the reflection of light that occurs on the surface of the current collector 5b can be reduced, and the output characteristics can be further improved.

As a modification of the solar cell element 10a, as shown in FIG. 4, a plurality of first output extraction parts 4c are formed in a direction along the reference side BS, and are located on both sides of the first output extraction part 4c. You may form the connection part 5c which electrically connects the current collection part 5b. According to such a configuration including the connecting portion 5c, the carriers collected by the current collecting portion 5b on the opposite side across the first output extraction portion 4c adjacent to the second output extraction portion 5a are efficiently second. This can be communicated to the output extraction unit 5a. Moreover, in the form shown in FIG. 4, since the 2nd output extraction part 5a is the aspect parallel to the 1st output extraction part 4c in the end of the 1st output extraction part 4c of one row | line | column, it showed in FIG. Compared with the configuration, the amount of light received by the second surface 1S can be increased. On the other hand, if the second output extraction portion 5a is provided in parallel with the first output extraction portion 4c at both ends of the first output extraction portion 4c in one row while providing the connection portion 5c, the resistance loss is reduced. It is preferable from the viewpoint. The connection portion 5c may be, for example, an oxide-based transparent conductive film such as SnO ₂ , ITO, or ZnO, but when the connection portion 5c is at a position overlapping the wiring material, it is formed of a metal such as silver, Resistance loss can be reduced without changing the amount of received light. In addition, it is preferable to provide an insulating layer such as an oxide film, resin, or insulating tape on the connection portion 5c. According to such a form, it can suppress that the wiring material mentioned later contacts the connection part 5c, and is short-circuited. The insulating layer may be provided on the wiring material.

  Next, the solar cell element 10b according to the second embodiment will be described. As shown in FIGS. 5 to 7, the solar cell element 10 b includes a semiconductor substrate 1 exhibiting one conductivity type, a reverse conductivity type layer 2 having a conductivity type different from the semiconductor substrate 1, and a semiconductor having the same conductivity type as the semiconductor substrate. A layer 6, a first electrode 4, and a second electrode 5 are provided. If necessary, the first surface 1F has a texture structure (uneven structure) 1a and / or an antireflection film 7 composed of a large number of fine protrusions 1b, and the passivation film 8 has a sunscreen on the second surface 1S. It is formed similarly to the battery element 10a.

  The reverse conductivity type layer 2 and the semiconductor layer 6 are provided on the second surface 1S side of the solar cell element 10b. A first electrode 4 is provided on the reverse conductivity type layer 2, a second electrode 5 is provided on the semiconductor layer 6, and the reverse conductivity type layer 2 has a wider width than the first electrode 4. Similarly, the semiconductor layer 6 has a width wider than that of the second electrode 5.

For example, the reverse conductivity type diffusion layer 2 diffuses phosphorus in the semiconductor substrate 1 made of silicon, has a dopant concentration of about 1 × 10 ¹⁸ to 1 × 10 ²¹ atoms / cm ^{3, and is} about 0.2 to 10 μm. Formed to a depth.

The semiconductor layer 6 is formed by, for example, diffusing boron or aluminum into the semiconductor substrate 1 made of silicon, having a dopant concentration of about 1 × 10 ¹⁸ to 1 × 10 ²¹ atoms / cm ³ and a depth of about 0.2 to 20 μm. Formed.

  In the solar cell element 10b, each of the first electrode 4 and the second electrode 5 is formed as a so-called comb-like electrode as shown in FIG. The first electrode 4 and the second electrode 5 each have a first current collector 4d and a second current collector 5d that collect carriers. The first electrode 4 includes a first auxiliary part 4e connected to the first current collecting part 4d, a wiring member that connects to the first auxiliary part 4e, and electrically connects adjacent solar cell elements. A first output extraction portion 4c having a role as a wiring connection portion to be connected. On the other hand, the 2nd electrode 5 is connected with the 2nd auxiliary | assistant part 5e connected with the 2nd current collection part 5d, and the 2nd auxiliary | assistant part 5e, and the wiring material which connects the adjacent solar cell elements electrically And a second output extraction portion 5a having a role as a wiring connection portion connected to the.

The first current collector 4d and the second current collector 5d have translucency and are alternately arranged in a direction parallel to the reference side BS. The first current collector 4d and the second current collector 5d are formed with a line width of 0.1 to 2 mm, and the distance between the first current collector 4d and the second current collector 5d is 0.1 to 0.2 mm. The thickness is 5 mm and the thickness is about 0.1 to 3 μm. The first current collector 4d and the second current collector 5d are formed of an oxide-based transparent conductive film such as SnO ₂ , ITO, or ZnO. In addition, if both the 1st current collection part 4d and the 2nd current collection part 5d are made into the aspect which has translucency like this embodiment, although it will become easier to receive light, for example, resistance loss will be reduced. From the viewpoint of reduction, only the second current collector 5d may be made of a light-transmitting material, and the first current collector 4d may be made of a metal material such as silver or copper having a small resistance loss.

A plurality of first auxiliary portions 4e are formed substantially perpendicular to the longitudinal direction of the first current collector 4d, and similarly, a plurality of second auxiliary portions 5e are formed substantially perpendicular to the longitudinal direction of the second current collector 5d. Has been. The line widths of the first auxiliary part 4e and the second auxiliary part 5e are the same as or wider than the first current collecting part 4d and the second current collecting part 5d, for example, 0.1 to 3 mm, and the first auxiliary part 5e And the second auxiliary portion 5e are formed to have a distance of 0.1 to 0.5 mm and a thickness of approximately 0.1 to 3 μm. The first auxiliary portion 4e and the second auxiliary portion 5e are preferably formed from an oxide-based transparent conductive film such as SnO ₂ , ITO, or ZnO, and both have translucency. Moreover, the resistance loss of an electrode can be reduced by forming a metal such as aluminum, silver, or copper as a main component in a single layer or multiple layers on a transparent conductive film. At this time, if the width of the metal layer is made smaller than the width of the transparent conductive film, it is preferable from the viewpoint that light shielded by the metal layer can be reduced.

  A plurality of first output extraction parts 4c are provided so as to be connected to one first auxiliary part 4e, and similarly a plurality of second output extraction parts 5a are provided so as to be connected to one second auxiliary part 5e. And the 1st output extraction part 4c provided in each 1st auxiliary part 4e and the 2nd output extraction part 5a provided in each 2nd auxiliary part 5e are arranged in the direction parallel to reference side BS, A plurality of columns are formed. The size of the first output extraction portion 4c and the second output extraction portion 5a is such a size that a wiring material can be connected, and is set to, for example, 4 to 10 mm, for example, a metal such as aluminum, silver, or copper as a main component. As a single layer or multiple layers.

  By having the configuration as described above, the solar cell element 10b according to the second embodiment is realized, and the first current collector 4d and the second current collector 5d have translucency, so that the semiconductor substrate 1 It is possible to receive not only the first surface 1F but also the second surface 1S, which can contribute to the improvement of the output characteristics of the solar cell element. Furthermore, the amount of light received from the second surface 1S can be increased by making the first auxiliary portion 4e and the second auxiliary portion 5e also have translucency. Further, in the above structure provided with a plurality of first auxiliary parts 4e and second auxiliary parts 5e, the first current collecting part 4d is required before the carrier reaches the first output extraction part 4c, as compared with the conventional structure. And the distance to move the first auxiliary portion 4e, similarly, the distance to move the second current collector 5d and the second auxiliary portion 5e before the carrier reaches the second output extraction portion 5a, can be shortened. Resistance loss can be reduced.

  Further, it is preferable that the width of the reverse conductivity type layer 2 is formed wider than the width of the semiconductor layer 6, and the width of the first current collector 4d is also made wider than the width of the second current collector 5d. As a result, the area of the pn depletion region, which is a semiconductor junction, increases, so that the carrier collection efficiency can be increased. For example, the width of the first current collector 4d is 1 to 2 mm, and the width of the second current collector 5d is 0.1 to 1 mm, preferably 0.1 to 0.5 mm.

≪Solar cell module≫
Next, an embodiment of the solar cell module of the present invention will be described. The solar cell module 20 according to the present embodiment is configured, for example, by arranging at least two solar cell elements 10 so as to be adjacent to each other and further connecting each other in series with a wiring material. The at least two solar cell elements 10 described above may be either the solar cell element 10a or the solar cell element 10b described above, or a solar cell module may be constituted by only one solar cell element, You may comprise a solar cell module using both solar cell elements.

  As shown in FIG. 8A, the solar cell module 20 includes a translucent member 11 made of glass or the like, a front side filler 12 made of a transparent ethylene vinyl acetate copolymer (EVA) or the like, and a plurality of solar cells. The battery element 10 is mainly provided with a back side filler 13 made of transparent EVA or the like, and a translucent back surface protective material 14 made of glass or the like. As shown in FIG. 8B, the plurality of solar cell elements 10 are formed by connecting adjacent solar cell elements 10 to each other in series by a wiring member 15 having a function as a connecting member. In the solar cell module according to the embodiment of the present invention, since the back side filler 13 and the back surface protective material 14 have translucency, light can be received from both sides, which contributes to improvement of output characteristics of the solar cell module. can do.

  The solar cell module 20 includes one first output extraction portion 4c (first electrode) of adjacent solar cell elements 10 and a second output extraction portion 5a (second electrode) of the other solar cell element 10. The wiring member 15 is electrically connected. In the following description, the solar cell module 20 shown in FIGS. 9 and 10 is formed by modularizing the above-described solar cell element 10a. On the other hand, the solar cell module 20 shown in FIGS. 11 and 12 is formed by modularizing the solar cell element 10b described above.

  As shown in FIGS. 9 to 12, the solar cell module 20 includes a first wiring member 15 a electrically connected to the first electrode 4 (first output extraction portion 4 c) of one solar cell element, and a second wiring member 15 a. The second wiring member 15b electrically connected to the electrode 5 (second output extraction portion 5a) is arranged so as to overlap in plan view from the second surface 1S side of the semiconductor substrate 1. Thus, since the solar cell module 20 can reduce the shadow (non-light receiving region) due to the wiring member 15 by adopting the above configuration, the amount of light received from the second surface 1S can be increased, Output characteristics can be improved.

  Further, as shown in FIGS. 10 and 12, in the solar cell module 20, the first output extraction portion 4c and the first wiring member 15a are in contact and electrically connected, but the second output extraction portion 5a. And the second wiring member 15b are electrically connected via a third wiring member 15c that connects the second output extraction portion 5a and the second wiring member 15b without being in direct contact with each other.

  As the wiring material 15 (first to third wiring materials), for example, a strip-shaped copper foil having a thickness of about 0.1 to 1 mm and a width of about 1 to 4 mm and whose entire surface is covered with a solder material is used in the longitudinal direction. What was cut | disconnected to predetermined length about can be used. In the case of the wiring material 15 covered with the solder material, the first output extraction part 4c of one solar cell element and the first solar cell element of the other solar cell element using hot air, soldering iron, etc., or a reflow furnace or the like. 2 It is soldered to the output extraction part 5a. The wiring member 15 is made of, for example, a metal such as copper or silver, and is made of a conductive adhesive made of a conductive filler such as low-temperature curable silver, nickel, or carbon. The wiring member 15 may be connected to the two-output extraction portion 5a. The first wiring member 15a connected to one solar cell element and the second wiring member 15b connected to another solar cell element provided adjacent to the one solar cell element are the first wiring member 15a and the first wiring member 15a. You may comprise by the member which united the 2 wiring materials 15b. Further, the second wiring member 15b and the third wiring member 15c may be connected by solder or a conductive adhesive. On the other hand, as shown in FIG. 13, the second wiring member 15b and the third wiring member 15c may be formed of a member in which the second wiring member 15b and the third wiring member 15c are integrated.

  In addition, as shown in FIGS. 10 and 12, the solar cell module 20 has the first wiring member 15 a and the second wiring member 15 interposed between the first wiring member 15 a and the second wiring member 15 b. Generation | occurrence | production of the short circuit by contact with the wiring material 15b can be suppressed. Furthermore, if the insulating material 19 is also provided at a position where the first wiring material 15a and the third wiring material 15c may come into contact with each other, a short circuit between the first wiring material 15a and the third wiring material 15c can be suppressed. It is preferable from the viewpoint.

  In the solar cell module 20, the first wiring member 15 a is disposed closer to the semiconductor substrate 1 than the second wiring member 15 b, and the second wiring member 15 b is viewed in plan from the second surface 1 S of the semiconductor substrate 1. If the first wiring member 15a is positioned within the region where the first wiring member 15a is disposed, the portion where the solar cell element is shaded is only the portion where the first wiring member 15a is disposed, and the shadow caused by the second wiring member 15b. Can reduce the effects of As a result, according to such a configuration, the amount of light received on the second surface side can be increased, which can contribute to the improvement of the output characteristics of the solar cell module.

  Moreover, it is preferable to provide the insulating layer 21 in the part which may short-circuit in the part which the wiring material 15 and the solar cell element 10 contact. For example, as shown in FIG. 12, an insulating layer 21 such as an oxide film, a resin, or an insulating tape is provided on a portion other than the connection region with the first output extraction portion 4 c that is in contact with the wiring member 15. preferable. According to such a form, it can suppress that the wiring material 15 and the 2nd electrode 5 contact and short-circuit. The insulating layer 21 may be provided on the wiring material 15.

  Moreover, as shown in FIGS. 14 and 15, the solar cell module 20 uses the insulating sheet 22 in which the first wiring member 15a, the second wiring member 15b, and the third wiring member 15c are incorporated therein to form each solar cell element. You may make it connect. In the region connected to the first output extraction portion 4c and the second output extraction portion 5a, an opening 22a is provided in the insulating sheet 22, and the wiring material 15 and the first output extraction portion 4c and the second are made of solder or a conductive adhesive. The output extraction unit 5a is connected. The insulating sheet 22 has translucency, and is made of, for example, an epoxy resin or a polyimide resin hybridized with silica. In addition, as shown in FIGS. 14 and 15, the insulating sheet 22 is formed in such a size that one solar cell element 10 can be mounted, and the first wiring member 15 a and the second wiring member 15 b of the adjacent insulating sheet 22. May be connected. The insulating sheet 22 may have a size that allows a plurality of solar cell elements 10 to be mounted. At this time, the first wiring member 15a connected to one solar cell element and the second wiring member 15b connected to another solar cell element provided adjacent to the one solar cell element are as shown in FIG. The first wiring member 15a and the second wiring member 15b may be integrated with each other.

≪Method for manufacturing solar cell element≫
Next, the manufacturing method of the solar cell element 10a and the solar cell element 10b is demonstrated.

<Preparation process of semiconductor substrate>
First, a semiconductor substrate 1 exhibiting a p-type conductivity is prepared.

  In the case of using a single crystal silicon substrate as the semiconductor substrate 1, the semiconductor substrate 1 can be obtained by cutting a single crystal silicon ingot produced by a known manufacturing method such as FZ or CZ method into a predetermined thickness. If a polycrystalline silicon substrate is used as the semiconductor substrate 1, the semiconductor substrate 1 is obtained by cutting a polycrystalline silicon ingot produced by a known manufacturing method such as a casting method or a solidification method in a mold into a predetermined thickness. be able to.

In the following, a crystalline silicon substrate that exhibits p-type conductivity by doping B (boron) or Ga (gallium) as a dopant element to about 1 × 10 ¹⁵ to 1 × 10 ¹⁷ atoms / cm ³ is used as a semiconductor substrate. The case of using as 1 will be described as an example.

  In addition, in order to remove the mechanical damage layer and the contamination layer of the surface layer portion of the semiconductor substrate 1 due to the cutting (slicing), the surface layer portions on the front surface side and the back surface side of the cut semiconductor substrate 1 are NaOH, KOH, or hydrofluoric acid Etching is about 10 to 20 μm each with a mixed solution of nitric acid and nitric acid, and then washed with pure water to remove organic components and metal components.

<Through-hole formation process>
Next, in the solar cell element 10a, the through hole 3 is formed between the first surface 1F and the second surface 1S of the semiconductor substrate 1.

  The through hole 3 is formed using a mechanical drill, a water jet, a laser processing apparatus, or the like. The through-hole 3 is formed by processing from the second surface 1S side of the semiconductor substrate 1 toward the first surface 1F side in order to avoid damage to the first surface 1F. However, if there is little damage to the semiconductor substrate 1 due to the processing, the processing may be performed from the first surface 1F side to the second surface 1S side. Moreover, it is preferable to etch after removing the through holes 3 in order to remove the damaged layer.

<Texture structure forming process>
Next, a texture structure 1 a having fine protrusions (convex portions) 1 b for effectively reducing the light reflectance is formed on the first surface side of the semiconductor substrate 1.

  As a method for forming the texture structure 1a, a wet etching method using an alkaline aqueous solution such as NaOH or KOH, or a dry etching method using an etching gas having a property of etching silicon which is a material of the semiconductor substrate 1 can be used.

<Reverse conductivity type layer formation process>
Next, the reverse conductivity type layer 2 is formed. In the solar cell element 10a, the first reverse conductivity type layer 2a is formed on the first surface 1F of the semiconductor substrate 1, the second reverse conductivity type layer 2b is formed on the inner surface of the through hole 3, and the second surface A third reverse conductivity type layer 2c is formed on 1S. On the other hand, in the solar cell element 10b, the reverse conductivity type layer 2 is formed on the second surface 1S.

  When a crystalline silicon substrate exhibiting p-type conductivity is used as the semiconductor substrate 1, it is preferable to use P (phosphorus) as an n-type doping element for forming the reverse conductivity type layer 2.

The reverse conductivity type layer 2 is a coating thermal diffusion method in which P ₂ O ₅ in a paste state is applied to the formation target portion of the semiconductor substrate 1 for thermal diffusion, and POCl ₃ (phosphorus oxychloride) in a gas state is a diffusion source. As described above, it is formed by a gas phase thermal diffusion method for diffusing to a formation target location, an ion implantation method for diffusing directly to a formation planned location, or the like. Use of the vapor phase diffusion method is preferable because, in the solar cell element 10a, the opposite conductivity type layer 2 can be formed simultaneously on the formation target portions on both main surfaces of the semiconductor substrate 1 and the surface of the through hole 3.

  In addition, under the condition that the diffusion region is formed in addition to the formation target portion, the diffusion is partially prevented by forming the diffusion prevention layer in advance and forming the reverse conductivity type layer 2 in that portion. be able to. Further, without forming the diffusion preventing layer, the diffusion region formed at a portion other than the formation target portion may be etched and removed later.

<Antireflection film formation process>
Next, the antireflection film 7 is formed on the first surface 1F of the semiconductor substrate 1.

As a method for forming the antireflection film 7, a PECVD method, a vapor deposition method, a sputtering method, or the like can be used. For example, when the antireflection film 7 made of a SiNx film is formed by PECVD, the reaction chamber is set to about 500 ° C. and a mixed gas of silane (Si ₃ H ₄ ) and ammonia (NH ₃ ) is nitrogen (N ₂ The antireflection film 7 can be formed by diluting with (3) and plasmaizing and depositing by glow discharge decomposition.

<Semiconductor layer formation process>
Next, the semiconductor layer 6 is formed on the second surface 1S of the semiconductor substrate 1.

When boron is used as a dopant element, it can be formed at a temperature of about 800 to 1100 ° C. by a thermal diffusion method using BBr ₃ (boron tribromide) as a diffusion source. In this case, prior to the formation of the semiconductor layer 6, a diffusion prevention layer made of an oxide film or the like, for example, on a region other than the portion where the semiconductor layer 6 is to be formed, for example, on the reverse conductivity type layer 2 or the like already formed It is desirable to remove the semiconductor layer 6 after the semiconductor layer 6 is formed.

  When aluminum is used as the dopant element, an aluminum paste made of aluminum powder and an organic vehicle or the like is applied to the second surface 1S of the semiconductor substrate 1 by a printing method, followed by heat treatment (baking at a temperature of about 700 to 850 ° C. The semiconductor layer 6 can be formed by diffusing aluminum toward the semiconductor substrate 1. In this case, the semiconductor layer 6 that is a desired diffusion region can be formed only on the second surface 1S that is the printing surface of the aluminum paste. Thereafter, the layer made of aluminum formed on the second surface 1S after firing is removed.

  When the reverse conductivity type layer 2 and the semiconductor layer 6 are formed adjacent to each other, pn separation may be performed by a known method such as laser irradiation.

<Passivation film formation process>
Next, a passivation film 8 is formed on the second surface 1S of the semiconductor substrate 1.

  As a method for forming the passivation film 8, a PECVD method, a vapor deposition method, a sputtering method, or the like can be used. When the passivation film 8 is formed, a mask is provided on a region other than the portion where the passivation film 8 is to be formed, or the region other than the portion where the passivation film 8 is to be formed is removed after being provided on the entire surface of the second surface 1S. May be.

<Method for forming electrode>
Next, in the solar cell element 10a, the main electrode portion 4a and the conduction portion 4b constituting the first electrode 4 are formed.

  The main electrode portion 4a and the conductive portion 4b are formed using, for example, a coating method. Specifically, 10 to 30 parts by weight of an organic vehicle and 0.1 to 10 parts by weight of glass frit are added to the first surface 1F of the semiconductor substrate 1 with respect to 100 parts by weight of metal powder made of, for example, silver. After forming a coating film by applying the conductive paste formed in the formation pattern of the main electrode portion 4a shown in FIG. 1, the coating film is tens of seconds to several tens of minutes at a maximum temperature of 500 to 850 ° C. The main electrode part 4a and the conduction | electrical_connection part 4b can be formed by baking to some extent. In this case, the conductive portion 4b can also be formed by filling the through-hole 3 with the conductive paste when applying the conductive paste. In addition, when the first output extraction portion 4c is formed of a conductive paste, the first output extraction portion 4c is formed by subsequently applying and baking the conductive paste from the second surface 1S side. can do. At this time, since the through-hole 3 is again filled with the conductive paste, firing is performed, so that when the conductive paste is applied to the first surface 1F, the through-hole 3 is not sufficiently filled with the conductive paste. It doesn't matter.

  In addition, after apply | coating an electrically conductive paste, it is preferable to evaporate the solvent in a coating film at predetermined temperature and to dry this coating film before baking. In addition, the conductive paste is filled and dried only in the through holes 3 in advance, and then the conductive paste is applied in the pattern of the main electrode portion 4a shown in FIG. The electrode part 4a and the conductive part 4b may be formed by separately applying and baking. Furthermore, you may make it form the main electrode part 4a, the conduction | electrical_connection part 4b, and the 1st output extraction part 4c by baking once.

  Further, as described above, when the antireflection film 7 is formed prior to the formation of the main electrode portion 4a, the main electrode portion 4a is formed in the patterned region, or the main electrode portion is formed by the fire-through method. 4a will be formed. On the other hand, the antireflection film 7 may be formed after the main electrode portion 4a is formed. In this case, it is not necessary to pattern the antireflection film 7, and it is not necessary to use the fire-through method, so that the conditions for forming the main electrode portion 4a are moderate. If it is such a process, the main electrode part 4a can be formed, without baking at the high temperature of about 800 degreeC, for example.

  Subsequently, a current collector 5b made of a transparent conductive film is formed on the second surface 1S of the semiconductor substrate 1. The current collector 5b is formed by a method such as sputtering, thermal CVD, or LPCVD. In that case, it is preferable to provide a mask on the area | region (non-formation area | region) which is not forming the current collection part 5b. In addition, when the passivation film 8 is formed on the second surface 1S before forming the current collecting portion 5b, for example, a sandblasting method or a mechanical scribing method in a point shape with an interval of 200 μm to 1 mm, or a laser. It is preferable to remove the passivation film 8 using a method or the like to form a contact portion between the semiconductor substrate 1 and the current collecting portion 5b. Alternatively, the passivation film 8 may be formed in a predetermined shape using a mask or the like so that the contact portion can be formed.

  Next, the first output extraction portion 4 c and the second output extraction portion 5 a are formed on the second surface 1 S of the semiconductor substrate 1. The first output extraction portion 4c and the second output extraction portion 5a are, for example, a method of applying a low-temperature curing type conductive paste having a conductive filler such as silver, and a heat treatment, or a metal such as aluminum, silver, or copper. Can be formed by sputtering or vapor deposition.

  Next, the electrode formation process of the solar cell element 10b will be described. In the solar cell element 10b, the first current collector 4d and the second current collector 5d are formed on the second surface 1S of the semiconductor substrate 1.

  The first current collector 4d and the second current collector 5d are made of a transparent conductive film, and are formed by a method such as sputtering, thermal CVD, or LPCVD. A mask may be provided on a region (non-formation region) where the first current collector 4d and the second current collector 5d are not formed, and a transparent conductive film is formed on the entire second surface 1S. Thereafter, an unnecessary transparent conductive film may be removed using a laser or the like so as to separate the first electrode 4 and the second electrode 5. Further, the transparent conductive film may be removed with a laser or the like and pn separation may be performed at the same time. Moreover, what is necessary is just to form the 1st auxiliary | assistant part 4e and the 2nd auxiliary | assistant part 5e simultaneously with the 1st current collection part 4d and the 2nd current collection part 5d, when forming with a transparent conductive film. In the case where the passivation film 8 is formed on the second surface 1S before the first current collector 4d and the second current collector 5d are formed, as in the solar cell element 10b, The predetermined region may be removed, or the passivation film 8 may be formed in a predetermined shape in advance.

  Next, the first output extraction portion 4 c and the second output extraction portion 5 a are formed on the second surface 1 S of the semiconductor substrate 1. The first output extraction part 4c and the second output extraction part 5a are, for example, a method of applying a low temperature curing type conductive paste having a conductive filler such as silver and heat treatment, or a metal such as aluminum, silver or copper. Can be formed by sputtering or vapor deposition. In addition, when the first auxiliary portion 4e and the second auxiliary portion 5e are also formed of metal, they may be formed simultaneously with the first output extraction portion 4c and the second output extraction portion 5a.

  The 1st solar cell element 10a and the 2nd solar cell element 10b which concern on this embodiment can be produced in the above procedures.

  In addition, when the insulating layer 21 is provided in a region where it is desired to avoid contact with the wiring material 15 when modularized, it may be formed using a thin film forming technique such as CVD, or a resin paste An embodiment in which an insulating paste made of, for example, is applied and then heat-treated may be used, or an embodiment in which an insulating tape made of polyimide resin, fluororesin or the like is attached may be used. In addition, when heat-treating the insulating paste, it can be formed by heat treatment simultaneously with the electrode formation.

≪Solar cell module manufacturing method≫
Next, a method for manufacturing the solar cell module 20 using the solar cell element 10 formed as described above will be described.

  First, the wiring material 15 is produced by cutting a copper foil having a thickness of about 0.1 to 0.4 mm and a width of about 2 mm covered with a solder material into a predetermined length in the longitudinal direction. Keep it. Then, the insulating material 19 is interposed between the first wiring material 15a and the second wiring material 15b so as to be integrated. As the insulating material 19, an insulating tape made of polyimide resin, fluorine resin, or the like may be used, or the first wiring material 15 a and the second wiring may be formed by an insulating adhesive such as a heat-resistant epoxy adhesive or an inorganic adhesive. An adhesive that is pasted and cured with the material 15 b may be used as the insulating material 19. In addition, when the second wiring member 15b and the third wiring member 15c are separate members, they may be connected in advance with solder or a conductive adhesive.

  Then, as shown in FIGS. 9 and 11, the plurality of solar cell elements 10 are placed at a predetermined distance with the second surface 1S facing upward, and the first output extraction portion 4c of the solar cell element 10 is placed. And the wiring material 15 is made to contact the 2nd output extraction part 5a from upper direction. In this state, the wiring material 15, the first output extraction portion 4 c, and the second output extraction portion 5 a are melted by using the hot air, the solder iron, or the reflow furnace to melt the solder on the surface of the wiring material 15. And connect. According to this method, the solar cell elements 10 can be connected with high productivity. In addition, it is composed of metals such as copper and silver, using epoxy, silicone, polyimide, polyurethane resin, etc. as a binder, and using a low-temperature curing type conductive adhesive composed of conductive fillers such as silver, nickel, and carbon. The wiring material 15 may be connected to the first output extraction portion 4c and the second output extraction portion 5a by providing a conductive adhesive and contacting the wiring material 15 on the conductive adhesive at about 150 to 250 ° C. By performing the heat treatment, the wiring member 15 is connected to the first output extraction portion 4c of one solar cell element 10 and the second output extraction portion 5a of the other solar cell element 10.

  In addition, when the insulating sheet 22 is used, the insulating sheet 22 includes a wiring member 15 in which the first wiring member 15a and the second wiring member 15b are integrated between two insulating films made of epoxy resin, polyimide resin, or the like. The first wiring member 15 and the second wiring member 15b may be sandwiched between the three insulating films using three insulating films. And in order to connect the 1st electrode 4 and the 2nd electrode 5, and the wiring material 15, a part of insulating film is removed with a laser etc. and the opening part 22a is formed. Then, solder or a conductive adhesive is provided in the opening 22a, and is heat-treated in contact with the first output extraction portion 4c and the second output extraction portion 5a of the solar cell element 10, thereby being provided inside the insulating sheet 22. The wiring member 15 is connected to the first output extraction portion 4c and the second output extraction portion 5a.

  Thereafter, the front-side filler 12, the plurality of solar cell elements 10 connected to each other by the wiring material 15, the back-side filler 13, and the back surface protective material 14 are sequentially laminated on the translucent member 11. The solar cell module 20 is obtained by integrating the module substrate obtained in (1) by degassing, heating and pressing in a laminator.

  And as shown in FIG.8 (b), the frames 16, such as aluminum, are inserted in the outer periphery of the solar cell module 20 mentioned above as needed. Moreover, as shown to Fig.8 (a), the terminal which is an output extraction part is used for the end of the electrode of the 1st solar cell element 10 and the last solar cell element 10 among several solar cell elements 10 connected in series. It is connected to the box 17 by an output extraction wiring 18.

  The solar cell module 20 according to this embodiment can be obtained by the procedure described above.

  In addition, the formation aspect of the reverse conductivity type layer 2 and the semiconductor layer 6 is not limited to what was mentioned above. For example, a crystalline silicon film including a hydrogenated amorphous silicon film or a microcrystalline silicon film may be formed using a thin film formation technique. In the solar cell element 10, the first output extraction portion 4 c and the second output extraction portion 5 a are respectively described above as long as the above arrangement state is satisfied and the connection mode by the wiring member 15 can be realized. A different shape (for example, a trapezoidal shape, a circular shape, an elliptical shape, a semicircular shape, a fan shape, or a composite shape thereof) may be used.

1: Semiconductor substrate 2: Reverse conductivity type layer 2a: 1st reverse conductivity type layer 2b: 2nd reverse conductivity type layer 2c: 3rd reverse conductivity type layer 3: Through-hole 4: 1st electrode 4a: Main electrode part 4b : Conduction part 4c: first output extraction part 4d: first current collection part 4e: first auxiliary part 5: second electrode 5a: second output extraction part 5b: current collection part 5c: connection part 5d: second collection Electrical part 5e: 2nd auxiliary | assistant part 6: Semiconductor layer 7: Antireflection film 8: Passivation film 9: Insulating layer 10: Solar cell element 11: Translucent substrate 12: Front side filler 13: Back side filler 14: Back surface protection Material 15: Wiring material 16: Frame 17: Terminal box 18: Output extraction wiring 19: Insulating material 20: Solar cell module 21: Insulating layer 22: Insulating sheet 22a: Opening of insulating sheet

Claims (4)

A semiconductor substrate having a first surface and a second surface corresponding to the back surface of the first surface;
A first electrode provided on the second surface;
A plurality of solar cell elements provided on the second surface and having a second electrode having a polarity different from that of the first electrode;
A solar cell module formed by electrically connecting the first electrode of one of the solar cell elements and the second electrode of the other solar cell element,
The second electrode includes a current collector,
The solar cell module, wherein the current collector has translucency. The solar cell element includes a first wiring material electrically connected to the first electrode, and a second wiring material electrically connected to the second electrode,
2. The solar cell module according to claim 1, wherein the first and second wiring members are arranged so as to overlap in plan view from the second surface of the semiconductor substrate. The first wiring member is disposed closer to the semiconductor substrate than the second wiring member;
3. The sun according to claim 2, wherein the second wiring member is located in a region where the first wiring member is disposed in a plan view from the second surface of the semiconductor substrate. Battery module. The solar cell module according to claim 2, wherein an insulating material is interposed between the first wiring material and the second wiring material.

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