JP5042101B2 - Solar cell and method for manufacturing the same - Google Patents

Description

  The present invention relates to a solar cell and a manufacturing method thereof.

  The solar cell has a PN junction at the focal point of a parabolic curved reflector in addition to a flat plate solar cell in which electrodes are attached to a flat semiconductor substrate whose PN junction surface is substantially parallel to the main surface of the substrate. There has been proposed a local concentrating solar cell in which a photoelectric conversion element is arranged to locally concentrate sunlight on a photoelectric conversion element positioned at the focal position of a reflecting mirror and perform photoelectric conversion (for example, Patent Documents). 1). Among these, a locally concentrating solar cell is manufactured by forming a spherical photoelectric conversion element and then mounting it on a support that is formed on a generally parabolic curved surface and also functions as an electrode of the photoelectric conversion element ( For example, see Patent Document 2).

JP 2003-56455 A JP 2002-164554 A

  However, when manufacturing a conventional flat plate solar cell, for example, a silicon ingot is sliced to form a wafer, so that cutting margins (dust) are generated, and wasteful silicon is generated, resulting in an increase in cost and bulk. There was a problem that silicon was relatively easy to break.

  In addition, when manufacturing a conventional locally concentrating solar cell, a minute spherical silicon must be produced, and further, a minute spherical silicon must be mounted at the focal point of a reflecting mirror formed in a parabolic curved surface. However, there is a problem that a high positional accuracy is required and at the same time, a slight misalignment causes a decrease in efficiency. Further, since fine alignment is necessary, there is a problem that the mounting time is increased and the manufacturing cost is increased.

  The present invention has been made in view of the above, and in a locally concentrating solar cell in which a photoelectric conversion element is arranged at the focal position of a parabolic curved reflector, the waste of material is eliminated, which is smaller than in the past. An object of the present invention is to obtain a solar cell and a method for manufacturing the solar cell that can reduce the fine alignment work of a photoelectric conversion element and reduce the manufacturing cost.

In order to achieve the above object, a solar cell according to the present invention includes a photoelectric conversion element having a PN junction and a first wiring connected to an electrode of the photoelectric conversion element and formed at a predetermined position. Solar cells are provided corresponding to the first substrate arranged in a matrix, and the photoelectric conversion elements on the first substrate, respectively, and a plurality of recesses having a parabolic reflection surface, A second substrate connected to the first wiring on the first substrate and having a second wiring for taking out the current generated by the photoelectric conversion element to the outside, the first substrate of the first substrate, The photoelectric conversion element formation surface and the concave portion formation surface of the second substrate are opposed to each other, and the photoelectric conversion element is bonded via a transparent resin so that the photoelectric conversion element is located at the focal position of the concave portion . The first wiring on the first substrate Through a through hole penetrating through the second substrate which is formed at a position to be connected to the line, characterized in that it is formed to a side opposite to the recessed surface of the second substrate.

  According to the present invention, the first substrate on which the photoelectric conversion element is formed in advance and the concave portion having a parabolic curved reflection surface provided corresponding to the formation position of the photoelectric conversion element on the first substrate are formed. Since the second substrate is aligned and bonded, the focal positions of all the parabolic curved reflectors on the substrate can be obtained only by the alignment operation between the first substrate and the second substrate. Thus, the photoelectric conversion element can be arranged, and the fine alignment work of the photoelectric conversion element is reduced as compared with the conventional solar cell. Furthermore, since the photoelectric conversion elements on the first substrate can be covered collectively with a parabolic curved reflection surface, the photoelectric conversion elements can be individually mounted on the reflection surface on the conventional parabolic curved surface. Thus, the time required for manufacturing the solar cell can be reduced, and the manufacturing cost can be suppressed.

  Exemplary embodiments of a solar cell and a method for manufacturing the solar cell according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments. In addition, cross-sectional views of photoelectric conversion devices used in the following embodiments are schematic, and the relationship between layer thickness and width, the ratio of the thickness of each layer, and the like are different from actual ones.

Embodiment 1 FIG.
1 is a plan view showing the structure of a solar cell according to the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG. In this solar cell, a concave portion 21 is formed on a glass substrate 10 as a first substrate having photoelectric conversion elements 11 formed in a matrix at predetermined positions, in a portion corresponding to the formation position of the photoelectric conversion elements 11. The formed resin substrate 20 as the second substrate has a structure in which the formation position of the photoelectric conversion element 11 and the formation position of the recess 21 are bonded together.

  On the glass substrate 10, the photoelectric conversion elements 11 are arranged in a matrix. This arrangement method is arbitrary, and may be a matrix type, a radial type, or a concentric type. In this example, the case where it is arranged in a matrix form is shown. In addition, the area | region including the reflective mirror which the one photoelectric conversion element 11 is arrange | positioned here and consists of the recessed part 21 of the resin substrate 20 shall be called the unit solar cell 2. FIG. In FIG. 1, the left-right direction on the paper surface is defined as the X-axis direction, and the direction perpendicular to the X-axis direction within the paper surface is defined as the Y-axis direction.

  The photoelectric conversion element 11 includes a first transparent electrode 12, a PN junction 13 in which a P-type silicon layer 14 and an N-type silicon layer 15 form a PN junction on a glass substrate 10, and a second transparent electrode 16. , Are sequentially stacked. The first transparent electrode 12 is made of a transparent conductive material such as ITO (Indium Tin Oxide), for example, and is in a region where the unit solar cells 2 of the glass substrate 10 are formed (hereinafter referred to as unit solar cell formation region). Patterned in a predetermined shape at a predetermined position. Here, the electrode portion 12A having a rectangular pattern of a predetermined size in the vicinity of the central portion in the unit solar cell formation region, and the lead line portion 12B extending in the X-axis direction from the electrode portion 12A, A first transparent electrode 12 is formed.

  A P-type silicon layer 14 is formed so as to cover the electrode portion 12A of the first transparent electrode 12. Further, the P-type silicon layer 14 is in close contact with the side surface where the lead line portion 12B of the P-type silicon layer 14 is not formed. A mold silicon layer 15 is formed. That is, a part of the N-type silicon layer 15 is formed on the glass substrate 10. As will be described later, the P-type silicon layer 14 and the N-type silicon layer 15 are formed by depositing silicon fine particles and then firing or solid-phase growth. Here, the P-type silicon layer 14 is formed so as to completely cover the electrode portion 12A of the first transparent electrode 12 when viewed from above.

  The second transparent electrode 16 has a glass substrate through an electrode portion 16A formed on the upper surface of the N-type silicon layer 15 and a side surface portion formed on the glass substrate 10 of the N-type silicon layer 15 from the electrode portion 16A. 10 and a lead line portion 16B formed along the Y-axis direction (that is, in a direction different from the lead line portion 12B of the first transparent electrode 12). Here, the first transparent electrode 12 is formed so as not to contact the N-type silicon layer 15, and the second transparent electrode 16 is formed so as not to contact the P-type silicon layer 14. The lead line portion 12B of the first transparent electrode 12 and the lead line portion 16B of the second transparent electrode 16 correspond to the first wiring in the claims.

  The resin substrate 20 is made of a light-transmitting organic material such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyethersulfone (PES), and corresponds to the formation position of the photoelectric conversion element 11 as described above. A recess 21 is formed in the portion to be performed. The concave portion 21 forms a parabolic surface, and a reflective film that reflects light incident from the concave portion 21 side is formed on the concave portion forming surface. Further, the position corresponding to the connection portion 12C of the lead line portion 12B of the first transparent electrode 12 and the position corresponding to the connection portion 16C of the lead line portion 16B of the second transparent electrode 16 of the resin substrate 20 are respectively Through holes 22A and 22B are provided, and the through holes 22A and 22B are filled with through wirings 23A and 23B made of a conductive material such as metal. On the surface of the resin substrate 20 that faces the surface where the recess 21 is formed, a wiring 24A that connects between the through wirings 23A of each unit solar cell 2, and a wiring 24B that connects between the through wirings 23B of each unit solar cell 2, Is formed so that a current can be taken out to the outside. The through wirings 23A and 23B and the wirings 24A and 24B correspond to the second wiring in the claims.

  The glass substrate 10 and the recess 21 of the resin substrate 20 are filled with a transparent resin 30, and the glass substrate 10 and the resin substrate 20 are bonded via the transparent resin 30. The resin 30 may be a transparent resin, but is preferably a resin material having a refractive index higher than that of the glass substrate 10. This is because if the refractive index is higher than that of the glass substrate 10, the optical path of light incident from the glass substrate 10 side becomes nearly vertical, and is reflected by the concave portion 21 and easily collected on the photoelectric conversion element 11. In this state, the photoelectric conversion element 11 is configured to be present at the focal position of the concave portion 21 having a parabolic curved surface.

  Next, the operation of such a locally concentrated solar cell will be described. FIG. 4 is a cross-sectional view schematically showing the state of sunlight incident on the locally concentrating solar cell according to the first embodiment. As shown in this figure, the light receiving surface is on the glass substrate 10 side on which the photoelectric conversion element 11 is formed. Part of sunlight that has entered the formation region of the recess 21 from the glass substrate 10 side is directly incident on the photoelectric conversion element 11, and other light is reflected on the inner surface of the recess 21 and then enters the photoelectric conversion element 11. Since the concave portion 21 forms a parabolic surface as described above, and the photoelectric conversion element 11 is disposed at the focal position of the parabolic curved surface, the light reflected by the inner surface of the concave portion 21 is the focal point. 11 is incident. In this way, sunlight incident on the solar cell is efficiently condensed on the photoelectric conversion element 11 by the recess 21.

  By the incidence of sunlight, holes are generated in the P-type silicon layer 14 of the photoelectric conversion element 11, and electrons are generated in the N-type silicon layer 15, which flow toward the first transparent electrode 12 and the second transparent electrode 16, respectively. Taken out as current. This current flows to the wiring 24A (24B) through the through wiring 23A (23B) connected to the first and second transparent electrodes 12 and 16, respectively, and is taken out to the outside.

  Next, a method for manufacturing a solar cell having such a structure will be described. FIGS. 5-1 to 10 are diagrams showing an example of the method for manufacturing the solar cell according to the first embodiment. 5-1 to 5-6 are cross-sectional views schematically illustrating an example of a method for manufacturing a photoelectric conversion element, and FIG. 6-1 is a cross-sectional view taken along the line CC in FIG. 5-5. -2 is a CC cross-sectional view of FIG. 5-6, and FIG. 7 is a plan view showing an example of a glass substrate on which a photoelectric conversion element is formed. 8 to 9-3 are diagrams illustrating an example of a method for manufacturing a resin substrate, FIG. 8 is a plan view of the resin substrate, and FIGS. 9-1 to 9-3 are illustrated in FIG. It is sectional drawing which shows an example of the manufacturing method of the resin substrate in DD sectional drawing. Furthermore, FIG. 10 is a cross-sectional view schematically showing a state in which a glass substrate and a resin substrate are bonded together.

  Initially, the formation procedure of the photoelectric conversion element 11 in a unit solar cell is demonstrated, referring FIGS. First, a first transparent electrode 12 such as an ITO film is formed on a glass substrate 10 by a printing method or the like so as to have a predetermined shape (FIG. 5-1). Here, in the unit solar cell formation region on the glass substrate 10, a rectangular electrode portion 12A is formed near the center, and a lead line portion 12B having a predetermined length is formed from the electrode portion 12A in the X-axis direction. Although not shown in a plan view, the width of the lead line portion 12B is narrower than the width of the electrode portion 12A.

  Subsequently, P-type silicon (Si) fine particles 51 are deposited on the electrode portion 12A of the transparent electrode 12 on the glass substrate 10 by a method such as spraying, mist, or inkjet coating to form a P-type silicon fine particle layer 52 (see FIG. Fig. 5-2). Thereafter, baking by heating or solid phase growth by laser is performed, so that the P-type silicon fine particle layer 52 is made the P-type silicon layer 14 (FIG. 5-3).

  Similarly, N-type silicon fine particles 53 are deposited on the P-type silicon layer 14 by a method such as spraying, mist or ink jet coating to form the N-type silicon fine particle layer 54 (FIG. 5-4), and heating or laser is performed. The N-type silicon layer 15 is formed by performing solid phase growth by (FIG. 5-5). At this time, as shown in FIG. 6A, the N-type silicon layer 15 is located on the right side of the P-type silicon layer 14 on the side where the second transparent electrode 16 is formed in the later step (right side in the figure). An overhang is formed, and a part thereof reaches the glass substrate 10. This is to prevent the second transparent electrode 16 to be formed later from being electrically connected to the P-type silicon layer 14. As described above, the PN junction 13 is formed.

  Here, the fine particles 51 and 53 are particles having a diameter on the order of 1 μm to several nm. In addition to newly manufactured silicon, the fine particles 51 and 53 are discharged when using waste materials such as silicon substrates used in discarded devices or silicon used in other products. Chips and the like can be used.

  Thereafter, the second transparent electrode 16 is formed in a predetermined shape by a printing method or the like so as to be continuously connected from the upper surface of the PN joined body 13 to a predetermined position on the glass substrate 10 (FIG. 5). -6). Here, as shown in FIG. 6B, the second transparent electrode 16 includes an electrode portion 16A formed on the upper surface of the PN junction 13 (N-type silicon layer 15) and the PN junction 13 (N-type). And a lead line portion 16B formed by a predetermined length in the Y-axis direction from the side surface of the silicon layer 15). Although not shown, the width of the lead line portion 16B is narrower than the width of the electrode portion 16A.

  FIG. 7 shows a plan view of the glass substrate 10 on which the photoelectric conversion element 11 is formed in the formation region of each unit solar cell in this way. In this example, the photoelectric conversion elements 11 are arranged at predetermined intervals in the X-axis direction and the Y-axis direction.

  Next, a method for manufacturing the resin substrate 20 will be described with reference to FIGS. First, a parabolic curved surface centered on a position corresponding to the position where the photoelectric conversion element 11 is formed on the glass substrate 10 is formed on one surface of a transparent resin substrate having the same plane dimensions as the glass substrate 10 shown in FIG. The concave portion 21 is formed by a method such as hot embossing (FIGS. 8 and 9-1). The recess 21 may be formed by integral molding using a mold or etching by plasma processing in addition to hot embossing. Thereafter, a reflective material film such as a metal capable of reflecting sunlight is formed in the formed recess 21. Thereby, the formation surface of the recessed part 21 turns into a reflective surface.

  Thereafter, a through hole 22A (22B) is formed at a predetermined position on the resin substrate 20 by a method such as laser processing (FIG. 9-2), and the through hole 22A (22B) is made of a conductive material such as metal. The through-wiring 23A (23B) is formed, and further, the wiring 24A (connected to the through-wiring 23A (23B) in the through-hole 22A (22B) is formed on the surface of the resin substrate 20 on the side facing the recess 21 formation surface. 24B) is formed (FIG. 9-3). The through wiring 23A (23B) can be formed by filling the through hole 22A (22B) with solder or performing metal plating such as copper plating. The through wiring 23 </ b> A (23 </ b> B) is connected to the connection portions 12 </ b> C and 16 </ b> C of the first and second transparent electrodes 12 and 16 in the unit solar battery cell 2 and serves as a current extraction line from the unit solar battery cell 2. The wiring 24A (24B) is made of a transparent conductive material such as ITO, and is formed by a film forming method such as a printing method or a sputtering method.

  Finally, the process which bonds the glass substrate 10 in which the photoelectric conversion element 11 was formed, and the resin substrate 20 is performed. As shown in FIG. 10, the resin substrate 20 coated with the transparent resin 30 on the concave 21 forming surface side is arranged with the surface coated with the resin 30 facing the photoelectric conversion element 11 forming surface side of the glass substrate 10, After aligning with the glass substrate 10, they are brought close to each other and bonded. At this time, the recess 21 is filled with the resin 30. By this bonding, the photoelectric conversion element 11 is arranged so as to be a focal position of the parabolic concave portion 21, and the bonding portions 12 </ b> C and 16 </ b> C of the first and second transparent electrodes 12 and 16 on the glass substrate 10 are arranged. The through wirings 23A and 23B formed on the resin substrate 20 are respectively connected. In addition, the joining method of both board | substrates may use what used thermocompression bonding and another adhesive other than the above-mentioned method. Thereby, the locally concentrating solar cell shown in FIGS. 1 to 3 is formed.

  According to the first embodiment, the resin substrate 20 having the concave portion 21 that is a parabolic curved reflector is placed on and bonded to the matrix unit solar cells that are arranged in advance on the glass substrate 10. Since it was set as the structure, the condensing device (concave part 21) can be provided on the photoelectric conversion element 11 of each unit photovoltaic cell 2 collectively. As a result, as compared with the case where a photoelectric conversion element is individually installed at the bottom of a conventional parabolic curved reflector (condenser), the time for manufacturing a solar cell is reduced to 1 / unit solar cell number. Can be shortened.

  Further, when the photoelectric conversion element 11 is formed, the silicon PN junction 13 is formed using the silicon fine particles 51 and 53 without using silicon cut out from the ingot as a raw material. It can be used effectively and the cost can be reduced. Furthermore, since the P-type silicon layer 14 and the N-type silicon layer 15 are formed with the fine particles 51 and 53, waste materials such as silicon substrates used in discarded devices as raw materials for the fine particles 51 and 53, Chips that are discharged when using silicon used in other products can be used. As a result, resources that have been used once can be reused or resources that should have been wasted can be used effectively. can do.

  In addition, sunlight incident from the transparent glass substrate 10 is reflected by a parabolic mirror surface (recessed portion 21) and condensed on the photoelectric conversion element 11 in the unit solar cell 2, so that it is compared with a bulk silicon solar cell. Thus, the amount of silicon necessary to obtain the same power generation efficiency can be reduced to about 1/5. That is, since the same power generation efficiency can be obtained with a small amount of silicon, the conversion efficiency as a whole also increases when compared with a bulk silicon solar cell.

Embodiment 2. FIG.
In the first embodiment, the PN junction is formed in the vertical direction with respect to the substrate surface of the glass substrate 10 (the PN junction surface is substantially parallel to the substrate surface). In other words, it may be formed in the left-right direction (the direction in which the PN junction surface is substantially parallel to the surface perpendicular to the substrate surface).

  FIG. 11 is a cross-sectional view showing an example of the configuration of the solar cell according to the second embodiment, and corresponds to the AA cross-sectional view of FIG. Moreover, FIG. 12 is sectional drawing which shows the part of a photoelectric conversion element typically. In the solar cell of the second embodiment, the P-type silicon layer 14 is formed so that the photoelectric conversion element 11 of the first embodiment covers the electrode portion 12A of the first transparent electrode 12 formed on the glass substrate 10. The N-type silicon layer 15 is formed on the glass substrate 10 in contact with the P-type silicon layer 14, and the second transparent electrode 16 is formed only on the N-type silicon layer 15. That is, the PN junction surface is formed in a direction substantially perpendicular to the substrate surface of the glass substrate 10. The first transparent electrode 12 is formed so as not to contact the N-type silicon layer 15, and the second transparent electrode 16 is formed so as not to contact the P-type silicon layer 14. Since the rest is the same as that of the first embodiment, the description thereof is omitted.

  In the photoelectric conversion element 11 having such a structure, after the first transparent electrode 12 is formed on the glass substrate 10, fine particles of P-type silicon are deposited on a predetermined region including the first transparent electrode 12. After the solid phase growth is performed to form the P type silicon layer 14, N type silicon fine particles are deposited on the glass substrate 10 in contact with the P type silicon layer 14, and the solid phase growth is performed to form the N type silicon layer 15. And the second transparent electrode 16 is formed on the N-type silicon layer 15.

  Furthermore, the photoelectric conversion element 11 having such a structure can be manufactured by other methods. For example, after the first transparent electrode 12 is formed on the glass substrate 10, fine particles of silicon, which is an intrinsic semiconductor, are deposited in a predetermined region including the first transparent electrode 12, and solid phase growth is performed to form a silicon layer. Then, P-type impurities are implanted into the silicon layer covering the first transparent electrode 12, and N-type impurities are implanted into the other regions to activate them. And an N-type silicon layer 15 may be formed. Thereafter, the second transparent electrode 16 is formed on the N-type silicon layer 15 to form the photoelectric conversion element 11.

  According to this Embodiment 2, since it comprised so that the PN junction surface of the photoelectric conversion element 11 might become a direction substantially perpendicular | vertical with respect to the substrate surface of the glass substrate 10, it reflected in the recessed part 21 of the unit photovoltaic cell 2 The amount of light incident on the PN junction surface can be increased as compared with the first embodiment. As a result, the effect that the power generation efficiency can be increased as compared with the case of the first embodiment can be obtained in addition to the effect of the first embodiment.

  In addition, the manufacturing method of the solar cell including the manufacturing method of the photoelectric conversion element 11 mentioned above is an example, and if the thing of an above-described structure is obtained, it may be manufactured using what kind of method. Moreover, although the example which used the glass substrate 10 was given as a 1st board | substrate, as long as it can endure the temperature at the time of the solid phase growth of the silicon layers 14 and 15, other transparency, such as a transparent resin substrate, is used. These substrates can also be used. In the above description, when the PN junction 13 is formed, the P-type silicon layer 14 and the N-type silicon layer 15 are used. However, the PN junction may be formed using other semiconductor materials.

  As described above, the solar cell according to the present invention is useful for a locally concentrating solar cell that performs photoelectric conversion by locally collecting sunlight.

It is a top view which shows the structure of the solar cell concerning this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is sectional drawing which shows typically the mode of incidence | injection of the sunlight to the local concentrating solar cell by this Embodiment 1. FIG. It is sectional drawing which shows an example of the manufacturing method of a photoelectric conversion element typically (the 1). It is sectional drawing which shows an example of the manufacturing method of a photoelectric conversion element typically (the 2). It is sectional drawing which shows an example of the manufacturing method of a photoelectric conversion element typically (the 3). It is sectional drawing which shows an example of the manufacturing method of a photoelectric conversion element typically (the 4). It is sectional drawing which shows typically an example of the manufacturing method of a photoelectric conversion element (the 5). It is sectional drawing which shows typically an example of the manufacturing method of a photoelectric conversion element (the 6). It is CC sectional drawing of FIGS. 5-5. It is CC sectional drawing of FIGS. 5-6. It is a top view which shows an example of the glass substrate in which the photoelectric conversion element was formed. It is a top view of a resin substrate. It is sectional drawing which shows an example of the manufacturing method of the resin substrate in DD sectional drawing of FIG. It is sectional drawing which shows an example of the manufacturing method of the resin substrate in DD sectional drawing of FIG. It is sectional drawing which shows an example of the manufacturing method of the resin substrate in DD sectional drawing of FIG. 8 (the 3). It is sectional drawing which shows a mode that a glass substrate and a resin substrate are bonded together. It is sectional drawing which shows an example of a structure of the solar cell by this Embodiment 2. FIG. It is sectional drawing which shows the part of a photoelectric conversion element typically.

Explanation of symbols

2 unit solar cell 10 glass substrate 11 photoelectric conversion element 12 first transparent electrode 12A, 16A electrode part 12B, 16B lead line part 12C, 16C connection part 13 PN junction 14 P-type silicon layer 15 N-type silicon layer 16 first Two transparent electrodes 20 Resin substrate 21 Recess 22A, 22B Through hole 23A, 23B Through wiring 24A, 24B Wiring 30 Resin 51, 53 Fine particle 52 P-type silicon fine particle layer 54 N-type silicon fine particle layer

Claims (7)

A photoelectric conversion element having a PN junction, is connected to an electrode of the photoelectric conversion elements, first the first wiring which is formed in a predetermined position, the unit solar cell having, arranged in a predetermined shape A substrate of
A plurality of recesses provided corresponding to the photoelectric conversion elements on the first substrate, each having a parabolic curved reflection surface, and the first wiring on the first substrate; A second substrate having a second wiring for extracting the current generated by the conversion element to the outside;
With
The photoelectric conversion element forming surface of the first substrate and the concave portion forming surface of the second substrate are opposed to each other through a transparent resin so that the photoelectric conversion element is positioned at the focal position of the concave portion. It joined Te,
The second wiring is formed in the concave portion of the second substrate through a through-hole penetrating the second substrate formed at a position connected to the first wiring on the first substrate. It is formed to the surface side which opposes a formation surface, The solar cell characterized by the above-mentioned.   2. The solar cell according to claim 1, wherein the photoelectric conversion element has a PN junction surface formed in a direction substantially parallel to a substrate surface of the first substrate.   2. The solar cell according to claim 1, wherein the photoelectric conversion element has a PN junction surface formed in a direction substantially parallel to a surface perpendicular to a substrate surface of the first substrate. A photoelectric conversion element having a PN junction, is connected to an electrode of the photoelectric conversion element, a first wiring that is in place, the unit solar cell having a first disposed in a predetermined shape A first substrate manufacturing process for manufacturing a substrate;
Provided corresponding to the photoelectric conversion element on the first substrate, connected to the concave portion having a parabolic curved reflection surface, and the first wiring on the first substrate, the photoelectric conversion element A second substrate manufacturing process for manufacturing a second substrate having a second wiring for taking out the generated current to the outside;
The photoelectric conversion element forming surface of the first substrate and the concave portion forming surface of the second substrate are opposed to each other through a transparent resin so that the photoelectric conversion element is positioned at the focal position of the concave portion. A substrate bonding process for bonding
Only including,
The second substrate manufacturing process includes:
Forming a recess having a parabolic curved surface at a predetermined position on the second substrate; and
A reflective film forming step of forming a reflective film on the formation surface of the recess;
A through hole forming step of forming a through hole penetrating the second substrate at a predetermined position of the second substrate;
A through wiring forming step of forming a through wiring in the through hole;
Forming a wiring that passes through the through wiring on a surface of the second substrate that faces the recess forming surface;
Method of manufacturing a solar cell characterized by containing Mukoto a. The first substrate manufacturing process includes:
A first transparent electrode forming step of forming a first transparent electrode at a predetermined position on the first substrate;
A PN junction formation step of forming a PN junction in which a semiconductor layer of a first conductivity type and a second conductivity type are bonded on the first transparent electrode;
A second transparent electrode forming step of forming a second transparent electrode from the PN junction body to a predetermined position on the first substrate;
Including
In the PN junction formation step, semiconductor fine particles having a particle diameter of 1 μm to several nm are deposited, followed by baking by heating or solid phase growth by laser irradiation, so that the first conductivity type and the second conductivity type are formed. The method for manufacturing a solar cell according to claim 4 , wherein a conductive type semiconductor layer is formed. In the PN junction formation step, the first conductivity type semiconductor layer is formed so that the PN junction surface is in a direction substantially parallel to the substrate surface of the first substrate, and then the first conductivity type is formed. 6. The method of manufacturing a solar cell according to claim 5 , wherein the second conductive type semiconductor layer is formed on the semiconductor layer. In the PN junction formation step, after forming the semiconductor layer of the first conductivity type so that the PN junction surface is in a direction substantially parallel to a plane perpendicular to the substrate surface of the first substrate, 6. The method for manufacturing a solar cell according to claim 5 , wherein the second conductive type semiconductor layer is formed in contact with the first conductive type semiconductor layer.

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