JP5094076B2 - Photoelectric conversion device, method for manufacturing the same, and photoelectric conversion module - Google Patents

Description

The present invention relates to the production how the photoelectric conversion equipment utilized in solar power generation or the like, particularly relates to a photoelectric conversion equipment manufacturing how using a crystalline semiconductor particles such as crystalline silicon grains as a photoelectric conversion element Is.

  Conventionally, as a condensing photoelectric conversion device, a condensing lens type photoelectric conversion device in which a condensing lens is disposed on a photoelectric conversion element, or a reflective type in which a reflective condensing body is disposed between photoelectric conversion elements. The photoelectric conversion device is known.

  Among these, as a condensing lens type photoelectric conversion device, one using a spherical lens formed parallel to the curved surface of the crystalline semiconductor particles has been proposed. However, if it is attempted to reduce the dependency of photoelectric conversion efficiency on the incident angle of light using such a spherical lens, the distance between the crystal semiconductor particles can be increased only to about 1/10 of the diameter of the crystal semiconductor particles. As a result, the amount of semiconductor used in the photoelectric conversion device is not reduced, which is disadvantageous for weight reduction and cost reduction.

  Moreover, as a reflective photoelectric conversion element, a photoelectric conversion device in which a substrate is deformed to form a reflective condensing body having a plurality of concave portions (reflective surfaces), and crystal semiconductor particles are respectively disposed at the bottoms of these concave portions. Is disclosed (Patent Document 1). In other words, this photoelectric conversion device uses a substrate as a reflection type condenser.

There has also been proposed a photoelectric conversion device in which a reflective condenser is formed using a member different from a substrate (Patent Document 2). Specifically, a reflective concentrator made of a metal bulk or a reflective concentrator in which a metal thin film is formed on the surface of a resin is disposed on a substrate. A plurality of recesses are provided for disposing the elements. Photoelectric conversion elements are respectively disposed in these recesses.
JP 2002-164554 A JP 2004-63564 A

  However, in the photoelectric conversion device described in Patent Literature 1, a multilayered member composed of a conductive substrate, an insulating layer, and a conductive layer is deformed into a convex shape to form a reflective concentrator having a plurality of concave portions. Therefore, it is difficult to reduce the width of the convex top portion of the reflective light collector. That is, since the multilayer structure member is bent to have a convex shape, if the convex apex portion is bent at an acute angle, the insulating layer may break and an electrical short circuit may occur between the substrate and the conductive layer. For this reason, since the width | variety of the convex top part of a reflective condensing body cannot be made small, the reflection amount of the light in this convex top part increases. As a result, there is a problem that the light collection rate is lowered and the photoelectric conversion efficiency is lowered.

  In addition, the photoelectric conversion device described in Patent Document 2 is manufactured by disposing each photoelectric conversion element in each concave portion of the reflective condensing body after disposing the reflective condensing body on the conductive substrate. Yes. That is, the conductive substrate, the reflective light collector, and the photoelectric conversion element are arranged in this order. In this photoelectric conversion element, a semiconductor layer made of an n-type semiconductor or a p-type semiconductor is formed on a part of the surface of a semiconductor particle made of a p-type semiconductor or an n-type semiconductor. However, the number of photoelectric conversion elements used in a photoelectric conversion device is usually tens of thousands or more, and therefore, after a reflective condensing body is disposed on a conductive substrate, photoelectric conversion is performed in each recess of the reflective condensing body. Arranging the elements one by one is a very cumbersome operation and causes an increase in cost. In addition, the photoelectric conversion elements must be arranged so that the portion where the semiconductor layer is not formed is in contact with the conductive substrate. There is a drawback in that if it is arranged in the wrong direction, it needs to be rearranged.

  Furthermore, in the photoelectric conversion device described in Patent Document 2, a metal thin film formed on the surface of the reflective condenser is used as the upper electrode. Since the thickness of the metal thin film is as thin as about 0.5 μm, there is a problem that a large current cannot flow. Moreover, in the manufacturing method described in Patent Document 2, after forming a reflective condensing body on a conductive substrate, a photoelectric conversion element is disposed in each recess of the reflective condensing body. Therefore, it is necessary to solder these in order to electrically connect the photoelectric conversion element and the metal thin film on the surface of the reflective light collector. Such an operation is very complicated, and electrical connection may be insufficient.

The present invention, photoelectric conversion efficiency is high, and an object thereof is to provide a manufacturing how the photoelectric conversion equipment which can be manufactured at low cost.

  The method for producing a photoelectric conversion device of the present invention includes a step of disposing a plurality of first-conductivity-type crystal semiconductor particles on a conductive substrate at intervals, and electrically connecting to the conductive substrate; Forming a second conductive type semiconductor layer on the surface of the crystalline semiconductor particles; forming an insulating layer on the conductive substrate and between the adjacent crystalline semiconductor particles; and on the insulating layer A step of forming a conductive layer for electrically connecting adjacent semiconductor layers, a step of forming a reflective concentrator for condensing the crystalline semiconductor particles and the semiconductor layer, and the conductive layer And a step of disposing the reflective condensing body between the adjacent crystalline semiconductor particles. Moreover, it is preferable to provide the process of removing a part by the side of the said conductive substrate in the said semiconductor layer.

  Further, in the step of disposing the crystal semiconductor particles on the conductive substrate, a plurality of the crystal semiconductor particles are supplied onto a suction substrate having a plurality of suction holes, and are sucked from the suction holes to be sucked into the suction holes. After the crystal semiconductor particles are respectively disposed on the substrate, heating is performed with the conductive substrate disposed substantially parallel to the suction substrate through the crystal semiconductor particles, and the crystal semiconductor particles are bonded to the conductive substrate. It is preferable to do.

  The photoelectric conversion device according to the present invention preferably includes a step of disposing an upper electrode, at least part of which is in contact with the conductive layer, between the reflective condenser and the insulating layer. The reflective condensing body includes a base made of a first resin, a surface layer portion formed on the surface of the base body and made of a second resin having a softening point lower than that of the first resin, and the surface layer portion. A temperature lower than the softening point of the first resin and higher than the softening point of the second resin in the step of disposing the reflective concentrator. More preferably, the reflective condensing body is bonded onto the conductive layer. Further, it is more preferable that a plurality of insulating hard particles are mixed in the insulating layer. More preferably, the conductive layer is a translucent conductive layer disposed on the insulating layer and the semiconductor layer.

  According to the photoelectric conversion device of the present invention, the photoelectric conversion device includes a reflective concentrator disposed on the conductive layer and having a plurality of reflection surfaces for reflecting light and condensing the photoelectric conversion element. Even if the area occupied by the photoelectric conversion element on the conductive substrate is small, incident light can be collected in the photoelectric conversion element, so that the amount of semiconductor used can be reduced, and the weight and cost can be reduced. In addition, since the reflective light collector in the present invention is disposed on the conductive layer, that is, formed separately from the conductive substrate, the width of the convex top of the reflective light collector. Can be reduced, and the reduction of the light collection rate can be prevented.

  The photoelectric conversion device of the present invention includes an upper electrode that is disposed between the reflective condenser and the insulating layer and at least a part of which is in contact with the conductive layer. Thus, since at least a part of the upper electrode is in contact with the conductive layer, the upper electrode can be used as a collecting electrode for extracting electric power generated from the photoelectric conversion device. In addition, since the upper electrode is disposed between the reflective collector and the insulating layer in this way, the upper electrode does not interfere with the collection of the reflective collector and efficiently collects light. Is possible.

  In addition, when the upper electrode has a flat plate shape and is disposed between the insulating layer and the conductive layer so as to be substantially parallel to the insulating layer, the upper electrode serves as a base for supporting the reflective condenser. Thereby, since the pressure at the time of arrange | positioning a reflection type condensing body on a conductive layer can be disperse | distributed by a flat upper electrode, it can prevent that an insulating layer fractures | ruptures by the said pressure. Therefore, it is possible to prevent an electrical short circuit between the conductive substrate and the conductive layer. Further, when the upper electrode has higher rigidity than the insulating layer and the translucent conductive layer, a more excellent effect of preventing this short circuit can be obtained. In addition, when the upper electrode has a lower electrical resistance than the translucent conductive layer, a larger current can be passed as compared with a conventional photoelectric conversion device without the upper electrode. In particular, a significantly larger current can be passed as compared with the conventional one using a metal thin film formed on the surface of the reflective light collector as the upper electrode.

  Further, a reflective condensing body includes a base made of a first resin, a surface layer portion formed on the surface of the base body and made of a second resin having a softening point lower than that of the first resin, and the surface layer portion And the metal thin film formed on the surface of the substrate, the smoothness of the surface is higher than when the resin constituting the reflective condensing body is made only of the first resin forming the base. As a result, light scattering is reduced. Thereby, the reflectance of a reflective condensing body improves and it can condense more efficiently. Moreover, the reflective condensing body formed by forming a metal thin film on the surface of the resin has an advantage that the reflectance is higher than that of the reflective condensing body made of a metal bulk.

  Moreover, when a plurality of insulating hard particles are mixed in the insulating layer, it is possible to prevent the insulating layer from being broken by the pressure when the reflective concentrator is disposed on the conductive layer. Thereby, an electrical short circuit between the conductive substrate and the conductive layer can be prevented.

  In addition, when the conductive layer in the present invention is a translucent conductive layer disposed on the insulating layer and the semiconductor layer, compared to the case where the conductive layer is formed using a metal or the like between the photoelectric conversion elements. Thus, the electrical connection can be ensured, and the process can be simplified.

  Since the photoelectric conversion device of the present invention can be manufactured, for example, by the method as described above, the manufacturing process is not complicated and an increase in cost can be suppressed. That is, the manufacturing method of the present invention includes a step of removing a part of the semiconductor layer on the conductive substrate side after disposing the crystalline semiconductor particles and the semiconductor layer on the conductive substrate. When arranging a plurality of crystalline semiconductor particles, these directions may be arbitrary directions, and it is not necessary to match a predetermined direction as in the prior art, and the process becomes very simple.

  In addition, instead of using the metal thin film formed on the surface of the reflective light collector as the upper surface side electrode as in the prior art, the conductive layer formed on the insulating layer functions as the upper surface side electrode. It is not necessary to perform such soldering, the process becomes very simple, and the reliability of electrical connection can be improved.

Hereinafter, with the photoelectric conversion equipment of the production how according to an embodiment of the present invention, with reference to the drawings will be described in detail. FIG. 1 is a plan view showing a photoelectric conversion device according to the present embodiment, and FIG. 2 is a sectional view thereof.

  As shown in FIGS. 1 and 2, this photoelectric conversion device includes a conductive substrate 3, a first conductive type crystalline semiconductor particle 7, and a second conductive type semiconductor layer 9 formed on the surface of the crystalline semiconductor particle 7. And a plurality of photoelectric conversion elements 5 disposed on the conductive substrate 3 with a space therebetween, and an insulating layer between the adjacent crystalline semiconductor particles 7 disposed on the conductive substrate 3. Insulating layer 11, disposed on insulating layer 11 and semiconductor layer 9, disposed on transparent conductive layer 13 and transparent conductive layer 13 for electrically connecting adjacent semiconductor layers 9 A reflective condensing body 15 having a plurality of reflecting surfaces for reflecting light and condensing it on each photoelectric conversion element 5; and between the reflective condensing body 15 and the insulating layer 11, And an upper electrode 23 partially embedded in the translucent conductive layer 13.

  Thus, in order to reduce the series resistance value between the translucent conductive layer 13 and the external terminal (not shown), the photoelectric conversion device 1 according to the present embodiment is between the adjacent crystal semiconductor particles 7. In addition, an upper electrode 23 partially embedded in the translucent conductive layer 13 is provided between the reflective condenser 15 and the insulating layer 11. As a result, the upper electrode 23 can efficiently collect light without disturbing the light collecting of the reflective light collecting body 15.

  The upper electrode 23 is a metal plate having an opening corresponding to the crystalline semiconductor particle 7. That is, the upper electrode 23 has a flat plate shape, and is disposed between the insulating layer 11 and the translucent conductive layer 13 in substantially parallel to the insulating layer 11. As a result, as will be described later, the flat upper electrode 23 disperses the pressure when the reflective condensing body 15 is disposed on the translucent conductive layer 13, so that the insulating layer 11 is broken by the pressure. This can be prevented. Therefore, an electrical short circuit between the conductive substrate 3 and the translucent conductive layer 13 can be prevented. The upper electrode 23 preferably has higher rigidity than the insulating layer 11 and the translucent conductive layer 13. Thereby, the more excellent effect which can prevent the said short circuit can be acquired.

  The upper electrode 23 is used as a collector electrode that takes out the photoelectric current generated by the photoelectric conversion element 5 from the photoelectric conversion device 1 without causing a resistance loss. Therefore, the upper electrode 23 is formed to have a lower electrical resistance than the translucent conductive layer 13. The thickness of the upper electrode 23 is preferably in the range of 20 to 200 μm. For the upper electrode 23, for example, a low-resistance conductor made of a metal such as aluminum, copper, nickel, chromium, silver, or an alloy thereof can be used.

  As shown in FIGS. 1 and 2, the reflective condensing body 15 is disposed on the translucent conductive layer 13. The reflective condensing body 15 is formed with a plurality of concave portions surrounded by a ridge line at the top of the hexagon. The surface of these recessed parts functions as a reflecting surface. This reflecting surface is for reflecting light and condensing it on the photoelectric conversion element 5, and preferably has a concave curved surface shape. The boundary in the front-end | tip part of adjacent concave curved surfaces is convex shape. The convex top is preferably narrow and pointed. Thereby, since the amount of incident light reflected at the top can be reduced, incident light can be efficiently collected on the photoelectric conversion element 5. Through holes that are slightly larger than the diameter of the photoelectric conversion element 5 are formed at the bottoms of the respective recesses close to the conductive substrate 3, and the photoelectric conversion elements 5 are disposed so as to protrude from these through holes. Yes.

The reflective surface of the reflective condensing body 15 is preferably formed so that the curvature decreases as the distance from the conductive substrate 3 increases. Thereby, more incident light can be condensed on the photoelectric conversion element 5. More preferably, as shown in Table 1, in order to reduce the incident angle dependency of light, the curved surface shape of the reflecting surface may be a curved surface shape of an elliptic rotating body. According to the simulation, when the incident angle changes like the sun, the curved surface shape made of an elliptical rotator can collect light more efficiently than the curved surface shape made of a sphere.

  The reflective light collector 15 may be formed of a metal bulk made of aluminum, an aluminum alloy, silver, or the like, but is preferably formed by forming a metal thin film 21 on the surface of a resin. In the case where the metal components are the same, the reflection type condensing body in which the metal thin film is coated on the resin has a higher reflectance than the reflection type condensing body made of a metal bulk, so that higher condensing efficiency can be obtained.

  Examples of the resin component constituting the reflective light collector 15 include polycarbonate, acrylic resin, fluororesin, and olefin resin. A metal thin film made of aluminum, an aluminum alloy, silver, or the like, more preferably a metal thin film 21 made of aluminum, is formed on the concave curved surface formed of such a resin. The metal thin film 21 tends to oxidize and decrease in reflectance when used for a long time. However, since the aluminum thin film has less decrease in reflectance compared to the case of using silver or the like, the light collection efficiency is improved. The decrease can be suppressed. The thickness of the metal thin film is preferably about 0.5 to 3.0 μm. FIG. 3 is a graph comparing the reflectivity (broken line) of a reflective concentrator made of aluminum bulk and the reflectivity (solid line) of a reflective concentrator in which an aluminum thin film is coated on a resin. As shown in this graph, it can be seen that the reflectance is higher when the resin is coated with an aluminum thin film than the aluminum bulk.

  The resin constituting the reflective light collector 15 may be composed of a single substance such as polycarbonate, acrylic resin, fluororesin, or olefin resin, but may be composed of two or more kinds of resins. preferable. Specifically, the reflective condensing body 15 is formed on the base 17 made of the first resin and the surface layer portion 19 made of the second resin having a softening point lower than that of the first resin. And a metal thin film 21 formed on the surface of the surface layer portion 19 is preferable. An example of the first resin that forms the substrate 17 is polycarbonate, and an example of the second resin that forms the surface layer portion 19 is acrylic resin.

The insulating layer 11 is disposed on the conductive substrate 3 and between the adjacent photoelectric conversion elements 5. This insulating layer 11 is for electrically separating the positive electrode and the negative electrode, and for electrically separating the conductive substrate 3 from the translucent conductive layer 13 or the upper electrode 23. It is. As this insulating layer 11, for example, low-temperature firing including, as optional components, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , CaO, MgO, P ₂ O ₅ , Li ₂ O, SnO, ZnO, BaO, TiO _{2 and the} like. Glass materials, glass materials in which fillers containing one or more of the above components are mixed, and organic insulating materials such as polyimide and silicon can be used.

  Insulating hard particles 25 are preferably mixed in the insulating layer 11. By mixing the insulating hard particles 25, it is possible to prevent the insulating layer 11 from being broken by the pressure when the reflective condenser 15 is disposed on the translucent conductive layer 13. Thereby, it is possible to prevent an electrical short circuit between the conductive substrate 3 and the translucent conductive layer 13. The size of the insulating hard particles 25 is preferably 4 to 20 μm. As the insulating hard particles 25, for example, an insulating material such as glass, ceramics, or resin can be used.

  As the conductive substrate 3, for example, aluminum, an aluminum alloy, a metal having a melting point higher than aluminum, ceramics, or the like can be used. Examples of the metal having a higher melting point than aluminum include iron, stainless steel, nickel alloy, and the like. Examples of ceramics include alumina ceramics. When the conductive substrate 3 is other than aluminum, it is preferable to form a conductive layer made of aluminum or the like on the surface.

  A plurality of the photoelectric conversion elements 5 are arranged on the conductive substrate 3 at intervals. The photoelectric conversion element 5 includes first conductive type crystalline semiconductor particles 7 and a second conductive type semiconductor layer 9 formed on the surface of the crystalline semiconductor particles 7.

  A plurality of crystalline semiconductor particles 7 constituting the photoelectric conversion element 5 are arranged on the conductive substrate 3 at intervals. The shape of the crystalline semiconductor particles 7 is preferably a spherical shape that has a convex curved surface and can reduce the dependence of the incident light on the light beam angle. The interval between the adjacent crystalline semiconductor particles 7 is preferably wide in order to reduce the amount of the crystalline semiconductor particles 7 used, but more preferably than the radius (1/2 of the particle size) of the crystalline semiconductor particles 7. Wide spacing is good. By disposing the crystal semiconductor particles 7 at an interval wider than the radius of the crystal semiconductor particles 7, the number of crystal semiconductor particles 7 becomes about ½ or less as compared with the case where the crystal semiconductor particles 7 are arranged in the closest packing.

The particle size of the crystalline semiconductor particles 7 is preferably 0.2 to 0.8 mm. This is because when the thickness exceeds 0.8 mm, the amount of silicon used in a plate-type crystal photoelectric conversion device including a cutting portion of a conventional silicon plate-like base crystal (wafer) is not changed, and there is an advantage of using the crystalline semiconductor particles 7. Disappear. Moreover, when smaller than 0.2 mm, the problem that the assembly to the conductive substrate 3 becomes difficult occurs. Accordingly, the particle size of the crystalline semiconductor particles 7 is preferably 0.2 to 0.8 mm in relation to the amount of silicon used. More preferably, the particle diameter of the crystalline semiconductor particles 7 is 0.2 to 0.6 mm. In the case of the p-type, the crystalline semiconductor particles 7 may be, for example, silicon (Si) containing a trace amount of elements such as boron (B), aluminum (Al), and gallium (Ga). In the case of n-type, for example, silicon containing a trace amount of elements such as phosphorus (P) and arsenic (As) can be used.

  The semiconductor layer 9 constituting the photoelectric conversion element 5 is formed on the surface of the crystalline semiconductor particles 7. The semiconductor layer 9 is preferably formed along the convex curved surface of the surface of the crystalline semiconductor particles 7. By being formed along the surface of the convex curved surface of the crystalline semiconductor particle 7, the area of the pn junction can be widely increased, and carriers generated inside the crystalline semiconductor particle 7 can be efficiently collected. .

  The semiconductor layer 9 may be crystalline, amorphous, or a mixture of crystalline and amorphous, but considering light transmittance, crystalline or a mixture of crystalline and amorphous. It is preferable to use what to do.

  The translucent conductive layer 13 is disposed on the photoelectric conversion element 5 and the insulating layer 11. The translucent conductive layer 13 is an electrode on the upper surface side that collects carriers generated inside the photoelectric conversion element 5. The electrode on the lower surface side is the conductive substrate 3. The translucent conductive layer 13 is preferably formed along the surfaces of the semiconductor layer 9 and the photoelectric conversion element 5, and is formed along the convex curved surface of the photoelectric conversion element 5. Thereby, the photoelectric conversion element 5 can be contacted in a wider area, and carriers generated inside the crystalline semiconductor particles 7 can be efficiently collected.

As the translucent conductive layer 13, one or more oxide materials selected from SnO ₂ , In ₂ O ₃ , ITO, ZnO, TiO _{2 and the} like can be used. In addition, the translucent conductive layer 13 can be expected to have an effect as an antireflection film if the film thickness is selected. In order to obtain the effect as an antireflection film, the film thickness is preferably adjusted to about 60 to 110 nm.

  A protective layer (not shown) may be formed on the surface of the semiconductor layer 9 or the translucent conductive layer 13. Since this protective layer is on the light incident side, it needs to be transparent, and in order to prevent current leakage between the semiconductor layer 9 or the translucent conductive layer 13 and the outside, it is made of a dielectric. It is necessary to be. As such a dielectric, for example, silicon oxide, cesium oxide, aluminum oxide, silicon nitride, titanium oxide, tantalum oxide, yttrium oxide, or the like can be used in a single composition or a composite composition. Such a dielectric can be formed by laminating a single layer or multiple layers on the surface of the semiconductor layer 9 or the translucent conductive layer 13 by a CVD method, a PVD method, or the like. In addition, the function as an anti-reflective film can also be provided by adjusting the film thickness of a protective layer to about 20-50 nm.

  A manufacturing method according to an embodiment of the present invention will be described. First, the crystalline semiconductor particles 7 are arranged on the conductive substrate 3 at intervals. At this time, the surface of the crystalline semiconductor particles 7 may be roughened. By making the surface rough, the reflectance on the surface of the crystalline semiconductor particles 7 can be reduced. Examples of a method for forming this rough surface include etching in an alkaline solution and fine processing using an RIE apparatus.

  After disposing the crystalline semiconductor particles 7 on the conductive substrate 3 at intervals, a eutectic temperature (577 ° C.) between aluminum forming the conductive substrate 3 and silicon forming the crystalline semiconductor particles 7 under a certain load. ) By heating as described above, the alloy layer 27 of the conductive substrate 3 and the crystalline semiconductor particles 7 is formed, and the conductive substrate 3 and the crystalline semiconductor particles 7 are bonded via the alloy layer 27.

  As another method for disposing the crystalline semiconductor particles 7 on the conductive substrate 3, for example, the following method can be cited. That is, a plurality of crystal semiconductor particles 7 are supplied onto a suction substrate having a plurality of suction holes, and the crystal semiconductor particles 7 are respectively disposed in the suction holes by suction from the suction holes. The crystalline semiconductor particles 7 may be bonded to the conductive substrate 3 by heating in a state where the conductive substrate 3 is disposed substantially parallel to the suction substrate.

  Next, a paste, solution, sheet, or liquid of an insulating material that preferably includes insulating hard particles 25 is applied onto the crystalline semiconductor particles 7 disposed on the conductive substrate 3 at intervals. Then, by heating at a temperature of 577 ° C. or less, which is the eutectic temperature of aluminum and silicon, the insulating layer 11 filled in the gaps between the crystalline semiconductor particles 7 and solidified by baking or thermosetting is formed. When the heating temperature exceeds 577 ° C., the alloy layer 27 of aluminum and silicon starts to melt, so that the bonding between the conductive substrate 3 and the crystalline semiconductor particles 7 becomes unstable, and in some cases, the crystalline semiconductor particles 7 become conductive. The generated current cannot be taken out from the conductive substrate 3. For this reason, heating temperature needs to be 577 degreeC or less.

  The semiconductor layer 9 is disposed on the surface of the crystalline semiconductor particles 7 that are not bonded to the conductive substrate 3 and the insulating layer 11. The semiconductor layer 9 is made of, for example, Si, and is formed of a vapor phase growth method or the like, for example, in the vapor phase of a silane compound. It is formed by introducing a small amount of either one of the gas phase.

  Further, the semiconductor layer 9 may be formed on the crystalline semiconductor particles 7 by a thermal diffusion method or the like before the crystalline semiconductor particles 7 are bonded to the conductive substrate 3. When the crystalline semiconductor particles 7 are, for example, p-type, an n-type layer having a thickness of 1 μm is formed on the surface by inserting the crystalline semiconductor particles 7 into a quartz tube at 900 ° C. for 30 minutes using phosphorus oxychloride as a diffusing agent. You can keep it. However, at this time, in order to separate the semiconductor layer 9 and the alloy layer 27, the surface of the semiconductor layer 9 is covered with an acid resistant resist or the like except for the vicinity of the alloy layer 27, and the uncovered portion is removed with an etching solution. Therefore, it is necessary to remove.

  After disposing the insulating layer 11 and the semiconductor layer 9 on the conductive substrate 3, the translucent conductive layer 13 is formed by a sputtering method, a vapor phase growth method, a coating baking method, or the like. The upper electrode 23 is disposed between the adjacent crystalline semiconductor particles 7 before and after the translucent conductive layer 13 is disposed.

  As a method of forming the reflective concentrator 15, a mold having a large number of negative shapes (concave shapes) of convex portions of the reflective concentrator 15 can be formed of a heat-resistant material such as metal, and the resin, metal, or shape can be maintained. Mold with material. The metal thin film 21 on the surface of the reflective condensing body 15 has high reflectivity such as Ag, Al, Au, Cu, Pt, Zn, Ni, and Cr by a method such as vacuum deposition, sputtering, electroless plating, and electrolytic plating. It is made of a metal having

  The reflective condensing body 15 thus formed is photoelectrically converted from the hole into the conductive substrate 3 on which the photoelectric conversion element 5, the insulating layer 11, and the translucent conductive layer 13 are already provided or formed. It covers so that the element 5 may penetrate, and it adhere | attaches as it is. Examples of the bonding method include vacuum heating. When the reflective condensing body 15 has the base 17 made of the first resin and the surface layer portion 19 made of the second resin as described above, the heating temperature is higher than the softening point of the first resin. A temperature that is small and greater than the softening point of the second resin is preferred.

  Further, the photoelectric conversion element 5 penetrates through the reflective condensing body 15 from the hole into the conductive substrate 3 on which the photoelectric conversion element 5, the insulating layer 11, and the translucent conductive layer 13 are already provided or formed. Further, a photoelectric conversion module may be manufactured by sequentially laminating a surface filler 29 and a surface protection plate 31 described later and sealing them with a vacuum heating device or the like.

  Next, the photoelectric conversion module according to the present embodiment will be described in detail. FIG. 4 is a cross-sectional view showing the photoelectric conversion module according to the present embodiment. As shown in FIG. 4, the photoelectric conversion module according to this embodiment includes the above-described photoelectric conversion device 1, and a surface disposed so as to cover the photoelectric conversion element 5 and the reflective condenser 15 in the photoelectric conversion device 1. It is disposed between the protective plate 31 and the surface protective plate 31 and the conductive substrate 3 and at least one of the peripheral portion and the inside of the conductive substrate 3 to prevent the reflection type light collector 15 from being deformed. And a surface filler 29 filled between the photoelectric conversion device 1 and the surface protection plate 31.

  The surface filler 29 is disposed on the reflective light collector 15. The surface filler 29 on the reflective light collector 15 may be an optically transparent material, and as a constituent material, ethylene vinyl acetate polymer (EVA), polyolefin, fluorine resin, silicon resin, or the like is used. Can do.

  The surface protection plate 31 is disposed on the surface filler 29 as shown in FIG. The surface protection plate 31 is formed on the surface of the photoelectric conversion module, thereby reducing the aging of the photoelectric conversion module. The surface protective plate 31 may be any material that is optically transparent and weather resistant, and examples of the constituent material include glass, silicon resin, polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), Polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkoxy copolymer (PFA), tetrafluoroethylene-6 fluoropropylene copolymer (FEP), polytrifluoroethylene chloride (PCTFE), etc. The fluororesin can be used.

  Further, the back surface filling material 33 can be provided on the back surface of the conductive substrate 3 using the same material as the material of the surface filling material 29, and a weather resistant material 35 may be further laminated. As a material of the weathering material 35, for example, a fluororesin such as polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), polytrifluoroethylene chloride (PCTFE), polyethylene terephthalate (PET), etc. Or a sheet obtained by laminating an aluminum foil or a metal oxide film using these resins, a metal sheet such as glass or stainless steel, or the like can be used.

The gap control unit 37 is disposed around or inside the photoelectric conversion device 1. The gap control unit 37 has a gap thickness between the surface protective material 31 and the photoelectric conversion device 1, and when the surface protective material 31, the surface filler 29 and the photoelectric conversion device 1 are combined and vacuum heated. By arranging it in the peripheral part of the photoelectric conversion device 1, it has a role of ensuring the interval so that the reflective condensing body 15 on the photoelectric conversion device 1 is not crushed. A plurality of gap control units 37 may be provided.

  Furthermore, it is preferable that a part of the reflective condensing body 15 is a gap control unit 37. Since the gap control unit 35 can be easily formed by adding to the design of the mold when forming the reflective light collector 7, it is not necessary to use a separate material or add another process. .

  In addition, the photoelectric conversion apparatus which provided the photoelectric conversion element 5 (unit of photoelectric conversion which has the one crystal semiconductor particle 7) of the structure mentioned above, or connected multiple (connected in series, parallel, or series-parallel). And Further, one photoelectric conversion device is provided, or a plurality of devices connected in series (connected in series, parallel, or series-parallel) is used as the power generation means, and the generated power is directly supplied from the power generation means to the DC load. Good. In addition, after the power generation means converts the generated power to appropriate AC power via power conversion means such as an inverter, the generated power can be supplied to an AC load such as a commercial power system or various electric devices. It is good also as a power generator. Furthermore, it is also possible to use such a power generation device as a photovoltaic power generation device such as a solar power generation system in various modes by installing it on the roof or wall surface of a building with good sunlight.

  Next, examples of the photoelectric conversion device of the present invention will be described. A photoelectric conversion element was produced as follows. Phosphorus diffusion treatment was performed on p-type silicon particles having a diameter of about 0.3 mm as crystalline semiconductor particles, and the pn junction was formed by forming the outer shell into an n + layer. A plurality of silicon particles are arranged on the main surface of the conductive substrate made of aluminum at an interval of about 0.6 times the diameter of the aluminum substrate, and the eutectic temperature of aluminum and silicon is about 577 ° C. or higher. A plurality of silicon particles were bonded onto the conductive substrate by heating for 10 minutes. After performing pn separation by etching a portion of the semiconductor layer close to the alloy layer of aluminum and silicon, an insulating layer made of polyimide was filled between a large number of silicon particles on the conductive substrate. . Thereafter, the upper surface of the silicon particles was washed, and an ITO film having a thickness of 80 nm was formed as a translucent conductive layer. Further, an upper electrode made of a thermosetting Ag paste was formed as a collecting electrode.

  Next, a reflective condenser was formed as follows. A polycarbonate resin film with an acrylic resin film formed on the surface by vacuum forming using a mold with a width of 1.6 times the diameter of silicon particles and a large number of vertically long semi-elliptical rotating shapes arranged in a conductive substrate 3 was formed into a shape having a plurality of concave curved surfaces with openings formed in a direction away from 3 and having through holes about the diameter of silicon particles at the bottom of each concave portion adjacent to the conductive substrate 3. Next, a metal thin film was formed by depositing aluminum on a concave curved surface formed of the resin by sputtering.

  Then, the reflective light collector is arranged on the photoelectric conversion element so that the photoelectric conversion element protrudes from the through hole of the reflective light collector, and the material made of EVA and a thickness of about 0.4 mm under the conductive substrate. About 0.1 mm-thick weathering material made of back surface filler and PET / SiO 2 / PET, about 0.6 mm-thick surface filling material made of EVA and ethylene-tetrafluoroethylene copolymer ( A surface protection plate made of ETFE) having a thickness of about 0.05 mm was sequentially laminated, and a photoelectric conversion module was produced by laminating with a vacuum laminator.

[Comparative example]
A photoelectric conversion element was produced as follows. In the same manner as in the example, phosphorus diffusion treatment was performed on a plurality of p-type silicon particles having a diameter of about 0.3 mm as crystalline semiconductor particles, and a pn junction was formed by forming an outer shell into an n + layer. A plurality of silicon particles are densely arranged on the main surface of an aluminum conductive substrate and heated at a temperature of 577 ° C. or more, which is the eutectic temperature of aluminum and silicon, for about 10 minutes to conduct a large number of silicon particles. Bonded on a conductive substrate. After performing pn separation by etching a portion of the semiconductor layer close to the alloy layer of aluminum and silicon, an insulating layer made of polyimide was filled between a large number of silicon particles on the conductive substrate. . Thereafter, the upper surface of the silicon particles was washed, and an ITO film having a thickness of 80 nm was formed as a translucent conductive layer. Further, an upper electrode made of a thermosetting Ag paste was formed as a collecting electrode.

  A material made of EVA under the conductive substrate, a back surface filler with a thickness of about 0.4 mm, and a weather resistant material with a thickness of about 0.1 mm made of PET / SiO 2 / PET, and about 0.00 mm made of EVA on the photoelectric conversion device. A photoelectric conversion module was manufactured by sequentially laminating a surface protective plate having a thickness of about 0.05 mm made of a 6 mm-thick surface filler and ethylene-tetrafluoroethylene copolymer (ETFE) and laminating with a vacuum laminator. In addition, the used quantity ratio of the Si sphere of the comparative example was about 2.42 times that of the example.

  As a result of measuring and comparing the photoelectric conversion efficiency per photoelectric conversion element of the photoelectric conversion module of the example and the photoelectric conversion efficiency per photoelectric conversion element of the photoelectric conversion module of the comparative example, the reflection type collector of the example is obtained. When formed, the photoelectric conversion efficiency is 2.38 times that of the photoelectric conversion element of the comparative example. Compared with the comparative example, the used quantity ratio of Si spheres is about 1 / 2.42 than that of the comparative example. Almost the same photoelectric conversion efficiency was obtained.

  In addition, this invention is not limited to said embodiment and Example, A various change can be given in the range which does not deviate from the summary of this invention.

It is a top view which shows the photoelectric conversion apparatus concerning one Embodiment of this invention. It is sectional drawing which shows the photoelectric conversion apparatus concerning one Embodiment of this invention. It is a graph which shows the reflectance of the reflective condensing body formed with the aluminum metal thin film or the aluminum bulk. It is sectional drawing which shows one Embodiment of the photoelectric conversion module formed using the photoelectric conversion apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoelectric conversion apparatus 3 ... Conductive substrate 5 ... Photoelectric conversion element 7 ... Crystalline semiconductor particle 9 ... Semiconductor layer 11 ... Insulating layer 13 ... Translucent conductive layer 15 ... Reflective light collecting body 17.. Base 19. Surface layer 21 metal thin film 23 upper electrode 25 insulating hard particles 27 alloy layer 29 of aluminum and crystalline semiconductor particles surface filler 31 ..Surface protection plate 33 ..Back surface filler 35 ..Weatherproof material 37 ..Gap control section

Claims (7)

A step of disposing a plurality of first-conductivity-type crystalline semiconductor particles on a conductive substrate at intervals, and electrically connecting to the conductive substrate;
Forming a second conductivity type semiconductor layer on the surface of the crystalline semiconductor particles;
Forming an insulating layer on the conductive substrate and between the adjacent crystalline semiconductor particles;
Forming a conductive layer on the insulating layer for electrically connecting adjacent semiconductor layers;
Forming a reflective condensing body for condensing the crystalline semiconductor particles and the semiconductor layer;
Disposing the reflective condenser on the conductive layer and between the adjacent crystalline semiconductor particles;
A process for producing a photoelectric conversion device, comprising: The method for manufacturing a photoelectric conversion device according to claim 1, further comprising a step of removing a part of the semiconductor layer on the conductive substrate side. In the step of disposing a plurality of crystal semiconductor particles on the conductive substrate, the plurality of crystal semiconductor particles are supplied onto a suction substrate having a plurality of suction holes, and are sucked from the suction holes to be sucked into the suction holes. After the crystal semiconductor particles are respectively disposed on the substrate, heating is performed with the conductive substrate disposed substantially parallel to the suction substrate through the crystal semiconductor particles, and the crystal semiconductor particles are bonded to the conductive substrate. The manufacturing method of the photoelectric conversion apparatus of Claim 2 characterized by the above-mentioned. 4. The method according to claim 1, further comprising a step of disposing an upper electrode, at least a part of which is in contact with the conductive layer, between the reflective collector and the insulating layer. The manufacturing method of the photoelectric conversion apparatus of description. The reflective condensing body includes a base made of a first resin, a surface layer portion formed on the surface of the base body and made of a second resin having a softening point lower than that of the first resin, and the surface layer portion A metal thin film formed on the surface,
In the step of disposing the reflective condenser, the reflective condenser is placed on the conductive layer at a temperature lower than the softening point of the first resin and higher than the softening point of the second resin. It joins, The manufacturing method of the photoelectric conversion apparatus in any one of Claims 1-4 characterized by the above-mentioned. The method for manufacturing a photoelectric conversion device according to claim 1, wherein a plurality of insulating hard particles are mixed in the insulating layer. The method for manufacturing a photoelectric conversion device according to claim 1, wherein the conductive layer is a translucent conductive layer disposed on the insulating layer and the semiconductor layer.

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