Solar cell, solar cell module, and manufacturing method for solar cell

Abstract

To provide a solar cell that has an improved light-receiving area per unit area compared to conventional products, a solar cell module, and a manufacturing method for a solar cell.SOLUTION: A solar cell has a metal layer laminated onto a photoelectric conversion substrate. The photoelectric conversion substrate includes a texture structure having multiple protrusions on a first main surface, The metal layer is thinner than the height of the protrusions and covering part of the protrusions. The protrusions have their tops exposed from the metal layer.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a solar cell, a solar cell module, and a method for manufacturing a solar cell. [Background technology]

[0002] Conventionally, in order to ensure high power generation efficiency, solar cells have a structure in which unevenness is provided on the surface of a photoelectric conversion substrate to confine light captured within the photoelectric conversion substrate (for example, Patent Document 1).

[0003] Furthermore, in a double-sided electrode type solar cell having electrodes on both sides, a comb-shaped collector electrode for extracting electricity from the photoelectric conversion substrate is also formed on the light-receiving surface. For example, in the solar cell of Patent Document 1, a collecting electrode is formed by applying and baking silver paste with a particle size in the range of 0.1 to 0.5 μm on the light-receiving surface of a photoelectric conversion substrate having a fine uneven surface. Patent Document 1 claims that this can reduce the contact resistance between the collecting electrode and the photoelectric conversion substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-133567 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to further improve the power generation efficiency, it is necessary to increase the light receiving area of ​​the photoelectric conversion substrate. However, in the solar cell of Patent Document 1, the silver paste is applied thicker than the height of the convex parts of the surface unevenness, and the parts where the silver paste is applied cannot receive light. Therefore, the solar cell of Patent Document 1 has room for improvement to further increase the light receiving area.

[0006] Therefore, an object of the present invention is to provide a solar cell, a solar cell module, and a method for manufacturing a solar cell, which have an improved light receiving area per unit area compared to conventional methods. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above-mentioned problems is a solar cell having a metal layer laminated on a photoelectric conversion substrate, the photoelectric conversion substrate having a texture structure having a plurality of convex portions on a first main surface, the metal layer being thinner than the height of the convex portions and covering part of the convex portions, and the convex portions having tops exposed from the metal layer.

[0008] According to this aspect, since the tops of the protrusions of the photoelectric conversion substrate are exposed from the metal layer, light can be incident from the top portions, and the light receiving area can be made larger than in the past.

[0009] In a preferred aspect, the photoelectric conversion substrate has a transparent conductive oxide layer laminated on a photoelectric conversion section, and the transparent conductive oxide layer constitutes the convex section.

[0010] In a preferred aspect, the texture structure has a plurality of recesses formed adjacent to the plurality of protrusions, the depth of the recesses is 1 μm or more, the metal layer contains a plurality of metal particles, the metal particles have a number average particle diameter of 10 nm or more and less than 100 nm, and are filled from the bottom of the recesses to a height of 1 / 20 to 2 / 3 of the depth of the recesses.

[0011] In a preferred aspect, the metal layer surrounds the tops of the protrusions when the photoelectric conversion substrate is viewed in plan.

[0012] A preferred aspect is one having a wiring member and a conductive adhesive, the wiring member being connected to a part of the metal layer via the conductive adhesive, and a convex portion exposed from the metal layer being covered and in contact with the conductive adhesive.

[0013] One aspect of the present invention is a solar cell module comprising the above-mentioned solar cell, a first sealing member and a second sealing member, wherein the solar cell is sandwiched and sealed between the first sealing member and the second sealing member, the first sealing member has an adhesive portion, the metal layer of the solar cell is adhered to the first sealing member in close contact with the adhesive portion, and a convex portion exposed from the metal layer is covered and in contact with the adhesive portion.

[0014] According to this aspect, an anchor effect occurs between the convex portion of the photoelectric conversion substrate and the adhesive portion of the first sealing member, and the adhesive strength between the photoelectric conversion substrate and the first sealing member can be improved compared to conventional techniques.

[0015] One aspect of the present invention is a method for manufacturing the above-mentioned solar cell, which includes a coating step of coating the photoelectric conversion substrate with a metal ink containing metal particles having a number average particle diameter of 10 nm or more and less than 100 nm, and a heating step of heating the photoelectric conversion substrate on which the metal ink has been coated at a heating temperature of 100°C or more and 180°C or less.

[0016] According to this aspect, the metal layer can be formed at a relatively low temperature, and the manufacturing cost can be reduced. Effect of the Invention

[0017] According to the present invention, the light receiving area per unit area can be improved as compared with the conventional art. [Brief description of the drawings]

[0018] [Figure 1] 1 is an explanatory diagram of a solar cell module according to a first embodiment of the present invention, in which (a) is a perspective view showing a schematic diagram of the solar cell module, and (b) is a cross-sectional view taken along line AA in (a). Note that hatching has been omitted to facilitate understanding. [Diagram 2] 1(a) is a cross-sectional view of the solar cell taken along line BB in FIG. [Diagram 3]1(a) is a cross-sectional view taken along the line CC of the solar cell shown in FIG. [Figure 4] FIG. 2 is an exploded perspective view of a main part of the solar cell of FIG. [Diagram 5] 5 is a cross-sectional view of the photoelectric conversion substrate of FIG. 4. Note that hatching has been omitted for ease of understanding. [Figure 6] FIG. 2 is an explanatory diagram of the solar cell in FIG. 1(a), where (a) is a plan view seen from the front side, and (b) is a plan view seen from the back side. [Figure 7] 2 is a cross-sectional view of a main part of a solar cell illustrating the optical path in the solar cell when light is irradiated onto the solar cell module of FIG. 1. Note that hatching is omitted for ease of understanding, and the optical path is indicated by an arrow. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described in detail.

[0020] The solar cell module 1 of the first embodiment of the present invention is a photoelectric conversion device that converts light into electricity, and receives light on at least one of its main surfaces. As shown in FIG. 1(a), the solar cell module 1 includes a solar cell string 2, a first sealing member 3, and a second sealing member 5 as main components.

[0021] (Solar cell string 2) As shown in FIG. 1(b), the solar cell string 2 includes a plurality of solar cells 10 (10a to 10c), wiring members 11 (11a, 11b), and a conductive adhesive 12, and the multiple solar cells 10 (10a to 10c) are connected in series by the wiring members 11 (11a, 11b). As shown in FIGS. 2 and 3, the solar cell 10 includes a photoelectric conversion substrate 20, a first collector electrode 21, and a second collector electrode 22.

[0022] (Photoelectric conversion substrate 20) As shown in Figures 2 and 3, the photoelectric conversion substrate 20 is a plate-shaped substrate having a first main surface 35 and a second main surface 36, and is a transparent conductive substrate in which a first transparent electrode layer 31 is laminated on the first main surface 35 side of the photoelectric conversion section 30 and a second transparent electrode layer 32 is laminated on the second main surface 36 side. In addition, the photoelectric conversion substrate 20 has a first texture structure 37 formed on a first main surface 35 which is the main surface facing the first sealing member 3, and a second texture structure 38 formed on a second main surface 36 which is the main surface facing the second sealing member 5.

[0023] The photoelectric conversion section 30 has a PN junction and is a section that converts light energy into electrical energy. As shown in Figure 5, the photoelectric conversion unit 30 has a first intrinsic semiconductor layer 41 and a first conductivity type semiconductor layer 42 stacked in this order on a first main surface 45 of a semiconductor substrate 40, and a second intrinsic semiconductor layer 43 and a second conductivity type semiconductor layer 44 stacked in this order on a second main surface 46.

[0024] The semiconductor substrate 40 is an n-type or p-type semiconductor substrate, specifically, an n-type or p-type crystalline silicon substrate. As the semiconductor substrate 40, a single crystal silicon substrate or a polycrystalline silicon substrate can be used. The semiconductor substrate 40 has pyramidal semiconductor-side texture structures 47, 48 formed on a first main surface 45 and a second main surface 46, respectively.

[0025] The first intrinsic semiconductor layer 41 is a silicon thin film that does not substantially contain a dopant, and the dopant concentration is preferably 1 / 100 or less of the dopant concentration of the first conductivity type semiconductor layer .

[0026] The first conductive type semiconductor layer 42 is an n-type or p-type silicon-based thin film layer containing a dopant, and in this embodiment is a p-type silicon layer.

[0027] The second intrinsic semiconductor layer 43 is a silicon thin film that does not substantially contain a dopant, and the dopant concentration is preferably 1 / 100 or less of the dopant concentration of the second conductivity type semiconductor layer 44 .

[0028] The second conductive type semiconductor layer 44 is a silicon layer that contains a dopant and has a conductive type opposite to that of the first conductive type semiconductor layer 42 . That is, when the conductivity type of the first conductivity type semiconductor layer 42 is n-type, the conductivity type of the second conductivity type semiconductor layer 44 is p-type, and when the conductivity type of the first conductivity type semiconductor layer 42 is p-type, the conductivity type of the second conductivity type semiconductor layer 44 is n-type. As described above, in this embodiment, the first conductive type semiconductor layer 42 is a p-type silicon layer, and therefore the second conductive type semiconductor layer 44 is formed of an n-type silicon layer.

[0029] The transparent electrode layers 31 and 32 are transparent conductive layers having transparency and conductivity, and specifically, are transparent conductive oxide layers made of a transparent conductive oxide such as indium tin oxide (ITO) or tungsten-doped indium oxide (IWO).

[0030] The first texture structure 37 is formed by the semiconductor layers 41, 42 and the first transparent electrode layer 31 following a semiconductor-side texture structure 47 of the underlying semiconductor substrate 40, as shown in FIG. That is, the first texture structure 37 has pyramidal projections and recesses, similar to the semiconductor-side texture structure 47 of the semiconductor substrate 40 , and is provided with a plurality of protrusions 51 . As shown in FIG. 4, the protrusion 51 has a quadrangular pyramid shape, the cross-sectional area of ​​which gradually decreases from the first transparent electrode layer 31 side toward the apex 52, and the apex 52 is pointed. Also, when viewed from another perspective, the first texture structure 37 has recesses 55 formed by adjacent protrusions 51, 51 as shown in FIG. The recess 55 has an inverted pyramid shape with a pointed bottom 56 . The depth of recess 55, that is, the height of protrusion 51 (the distance between top 52 and bottom 56 in the thickness direction) is greater than the thickness of first collector electrode 21 as shown in FIG. 4, and is preferably 1 μm or more and 10 μm or less.

[0031] The second texture structure 38 is formed by the semiconductor layers 43, 44 and the second transparent electrode layer 32 following the semiconductor-side texture structure 48 of the underlying semiconductor substrate 40, as shown in FIG. That is, the second texture structure 38 has pyramidal projections and recesses, similar to the semiconductor-side texture structure 48 of the semiconductor substrate 40 , and is provided with a plurality of protrusions 61 . As shown in FIG. 4, the protrusion 61 has a quadrangular pyramid shape, the cross-sectional area of ​​which gradually decreases from the second transparent electrode layer 32 side toward the apex 62, and the apex 62 is pointed. 5, the second texture structure 38 has a recess 65 formed by adjacent protrusions 61, 61. When viewed from another perspective, as shown in FIG. The recess 65 has an inverted pyramid shape with a pointed bottom 66 . The depth of the recess 65, that is, the height of the protrusion 61 (the distance between the top 62 and the bottom 66 in the thickness direction) is greater than the thickness of the second collector electrode 22 as shown in FIG. 4, and is preferably 1 μm or more and 10 μm or less.

[0032] (Collector electrode 21, 22) First collector electrode 21 is paired with second collector electrode 22 and serves as an extraction electrode that, together with second collector electrode 22 , extracts from photoelectric conversion substrate 20 the electric energy photoelectrically converted in photoelectric conversion substrate 20 . The collecting electrodes 21, 22 are formed partially on both main surfaces 35, 36 of the photoelectric conversion substrate 20, and are mainly composed of metal electrode layers 70a, 70b. The metal electrode layers 70a and 70b are metal layers having higher conductivity than the transparent electrode layers 31 and 32, and are formed of a plurality of metal particles 71 as shown in FIGS. The thickness of the metal electrode layers 70a, 70b is thinner than the height of the protrusions 51, 61, and is preferably 0.1 μm to 10 μm, more preferably 0.2 μm to 5 μm, and further preferably 1 μm or less. The metal particles 71 are particles on the nano-size order, and have a diameter smaller than the height of the protrusions 51 and 61 . The metal particles 71 preferably have a number average particle size of 10 nm or more and less than 100 nm. The number average particle size can be calculated, for example, by confirming the particle sizes of 100 samples using a scanning electron microscope or a transmission electron microscope and taking the arithmetic average. The metal particles 71 can be made of, for example, gold, silver, copper, platinum, aluminum, nickel, palladium, or the like. The metal particles 71 in this embodiment are silver particles. The metal electrode layers 70a, 70b are preferably formed by inkjet printing or screen printing, and more preferably by inkjet printing. The metal electrode layers 70a and 70b of this embodiment are formed by applying a metal ink containing metal particles 71 onto the photoelectric conversion substrate 20, as described below.

[0033] Further, the first collecting electrode 21 is composed of a first bus bar electrode portion 80a and a first finger electrode portion 81a when the photoelectric conversion substrate 20 is viewed in plan from the first main surface 35 side, as shown in FIG. 6(a). As shown in FIG. 6(b), when photoelectric conversion substrate 20 is viewed in plan from second main surface 36 side, second collecting electrode 22 is composed of second bus bar electrode portion 80b and second finger electrode portion 81b. The bus bar electrode portions 80a, 80b are portions that have a width in the horizontal direction and extend in the vertical direction. The finger electrode portions 81a, 81b are portions extending in a comb-teeth shape from the middle portions of the busbar electrode portions 80a, 80b. The finger electrode portions 81a, 81b extend in a direction intersecting the extension direction of the busbar electrode portions 80a, 80b, and in this embodiment, extend in a direction perpendicular to the extension direction of the busbar electrode portions 80a, 80b. That is, the finger electrode portions 81a, 81b have a width in the vertical direction and extend in the horizontal direction. The finger electrode portions 81a, 81b are narrower than the bus bar electrode portions 80a, 80b and wider than the protrusions 51, 61.

[0034] (Wiring member 11) As shown in FIG. 1, the wiring member 11 is a tab wiring that connects adjacent solar cells 10, 10 together. Wiring member 11a has a first connection portion that connects to bus bar electrode portion 80a of one of adjacent solar cells 10a, 10b, and a second connection portion that connects to bus bar electrode portion 80b of the other solar cell 10b.

[0035] (Conductive adhesive 12) The conductive adhesive 12 adheres the connection portions of the wiring member 11 to the bus bar electrode portions 80a, 80b of the solar cell 10. There are no particular limitations on the conductive adhesive 12 as long as it has conductivity and adhesiveness. For example, solder can be used as the conductive adhesive 12.

[0036] (Sealing member 3, 5) As shown in FIG. 1, the first sealing member 3 extends in a planar shape and seals the solar cell string 2 together with the second sealing member 5 . The sealing portion 100 is composed of a transparent insulating substrate or sheet having light transmitting and insulating properties, and for example, a glass substrate or a resin sheet can be used. The adhesive portion 101 is made of a light-transmitting adhesive material having light-transmitting and adhesive properties, and is preferably made of a thermoplastic resin. For example, an EVA sheet can be used as the adhesive portion 101. The second sealing member 5, like the first sealing member 3, has a planar extension and includes a sealing portion 102 and an adhesive portion 103. The sealing portion 102 is made of an insulating substrate or sheet having insulating properties, and for example, a glass substrate or a resin sheet can be used. The adhesive portion 103 is made of an adhesive material having adhesive properties, and is preferably made of a thermoplastic resin. For example, an EVA sheet can be used as the adhesive portion 101.

[0037] Next, a manufacturing method for the solar cell module 1 of the first embodiment will be described.

[0038] The method for manufacturing the solar cell module 1 of this embodiment mainly includes a photoelectric conversion substrate forming step, a collector electrode forming step, a wiring attaching step, and a sealing step.

[0039] In the manufacturing method of the solar cell module 1 of this embodiment, first, a first intrinsic semiconductor layer 41 and a first conductivity type semiconductor layer 42 are formed on a first main surface 45 of a semiconductor substrate 40 on which semiconductor side texture structures 47, 48 have been formed in advance, by plasma CVD, and a second intrinsic semiconductor layer 43 and a second conductivity type semiconductor layer 44 are formed on a second main surface 46 of the semiconductor substrate 40, thereby forming a photoelectric conversion section 30 (photoelectric conversion section formation process). Next, a first transparent electrode layer 31 is formed on the first main surface 45 side of the photoelectric conversion section 30 by sputtering, and a second transparent electrode layer 32 is formed on the second main surface 46 side (transparent electrode layer formation process), and a photoelectric conversion substrate 20 is formed (photoelectric conversion substrate formation process).

[0040] At this time, the photoelectric conversion substrate 20 has a texture structure 37 formed on the first main surface 35 that reflects the texture structure 47 of the semiconductor substrate 40, and a texture structure 38 formed on the second main surface 36 that reflects the texture structure 48 of the semiconductor substrate 40.

[0041] Next, a metal ink containing metal particles 71 is applied in a predetermined pattern onto the first main surface 35 and the second main surface 36 of the photoelectric conversion substrate 20 by an inkjet method (application process), and the photoelectric conversion substrate 20 with the metal ink applied thereto is heated and baked at a heating temperature T1 for a heating time t1 (heating process) to form collecting electrodes 21, 22 (collector forming process).

[0042] At this time, the metal electrode layers 70 a , 70 b constituting the collector electrodes 21 , 22 are formed by filling the bottoms 56 , 66 of the recesses 55 , 65 of the photoelectric conversion substrate 20 with the metal particles 71 . The metal particles 71 are preferably filled to a height of 1 / 20 to 2 / 3 of the depth of the recesses 55, 65 from the bottoms 56, 66 of the recesses 55, 65, and more preferably filled to a height of 1 / 10 to 1 / 2. 2, 3, and 5, holes are formed in the metal electrode layers 70a and 70b constituting the collecting electrodes 21 and 22 so as to avoid the protruding portions 51 and 61. That is, the tops 52 and 62 of the protruding portions 51 and 61 of the photoelectric conversion substrate 20 are not covered with the metal particles 71, and the vicinity of the tops 52 and 62 is exposed from the holes of the collecting electrodes 21 and 22, forming exposed regions 110. In other words, the metal electrode layers 70a and 70b surround the tops 52 and 62 of the protruding portions 51 and 61 when viewed in a plan view as in FIG. The metallic ink used at this time is one in which metallic particles 71 are dispersed in a dispersion liquid. The heating temperature T1 at this time is a temperature at which the dispersion solvent volatilizes or vaporizes, and substantially only the metal particles 71 remain as the metal electrode layers 70a and 70b. The phrase "substantially only metal particles 71 remain" means that 98% or more of the total components remain as metal particles 71. The heating temperature T1 is preferably 100° C. or higher and 180° C. or lower, and more preferably 150° C. or lower. The heating time t1 is appropriately set together with the heating temperature T1, and is preferably, for example, from 5 minutes to 2 hours, and more preferably from 20 minutes to 1 hour. The dispersion solvent may be an inorganic solvent such as water or an organic solvent, as long as only the metal particles 71 remain substantially after heating at the heating temperature T1. As the dispersion solvent, for example, a mixed solvent of a hydrocarbon and an alcohol can be used.

[0043] Next, wiring members 11 are attached to the busbar electrode portions 80a, 80b of the collector electrodes 21, 22 via conductive adhesive 12, and each solar cell 10 is electrically connected in series or in parallel by the wiring members 11 to form a solar cell string 2 (wiring connection process).

[0044] At this time, the conductive adhesive 12 covers and straddles the collecting electrodes 21, 22 and the exposed regions 110 of the protrusions 51, 61 in the busbar electrode portions 80a, 80b, and is in contact with the exposed regions 110 of the protrusions 51, 61. That is, the conductive adhesive 12 and the exposed regions 110 of the protrusions 51, 61 are engaged with each other.

[0045] Next, the solar cell string 2 is sealed by sandwiching it between sealing members 3 and 5 (sealing step), and then, similar to a conventional solar cell module, post-processing such as wiring is performed to complete the solar cell module 1.

[0046] At this time, the adhesive parts 101, 103 of the sealing members 3, 5 are in contact with and cover the collecting electrodes 21, 22, the exposed regions 110 of the protrusions 51, 61, and the wiring member 11 in the finger electrode portions 81a, 81b, and the exposed regions 110 of the protrusions 51, 61 are embedded therein. That is, the adhesive parts 101, 103 of the sealing members 3, 5 and the exposed regions 110 of the protrusions 51, 61 are engaged with each other.

[0047] According to the solar cell 10 of the first embodiment, the thickness of the metal electrode layers 70a, 70b is thinner than the height of the protrusions 51, 61 and covers part of the protrusions 51, 61, so that the tops 52, 62 of the protrusions 51, 61 of the photoelectric conversion substrate 20 are exposed from the metal electrode layers 70a, 70b. Therefore, light can be incident from the tops 52, 62 as shown in Fig. 7, and the light receiving area can be increased compared to the conventional art, thereby improving the power generation efficiency.

[0048] According to the solar cell 10 of the first embodiment, the protrusions 51, 61 are formed on the transparent electrode layers 31, 32 laminated on the photoelectric conversion section 30, so that most of the photoelectric conversion section 30 can receive light.

[0049] According to the solar cell 10 of the first embodiment, the metal particles 71 constituting the metal electrode layers 70a, 70b have a number average particle diameter of 10 nm or more and less than 100 nm, and are filled from the bottoms 56, 66 of the recesses 55, 65 to a height of 1 / 20 to 2 / 3 of the depth of the recesses 55, 65. Therefore, the metal particles 71 penetrate deeply into the bottoms 56, 66 of the recesses 55, 65, making it possible to reduce the contact resistance compared to conventional techniques.

[0050] According to the solar cell 10 of the first embodiment, the metal electrode layers 70a, 70b surround the tops 52, 62 of the protrusions 51, 61 when the photoelectric conversion substrate 20 is viewed in plan, so that the metal electrode layers 70a, 71b are continuous in the planar direction. That is, the conductive paths of the metal electrode layers 70a, 70b are not interrupted by the protrusions 51, 61, so that electric power can flow stably, and the reliability of the electrodes can be ensured even if the protrusions 51, 61 are exposed from the metal electrode layers 70a, 70b.

[0051] According to the solar cell 10 of the first embodiment, the wiring member 11 is connected to a part of the metal electrode layer 70a (70b) via the conductive adhesive 12, and the protrusions 51 (61) of the photoelectric conversion substrate 20 exposed from the metal electrode layer 70a (70b) are covered and in contact with the conductive adhesive 12. Therefore, an anchor effect occurs between the protrusions 51 (61) and the conductive adhesive 12, and the adhesive strength at the interface between the conductive adhesive 12 and the photoelectric conversion substrate 20 can be improved.

[0052] According to the solar cell module 1 of the first embodiment, the solar cell 10 has the metal electrode layers 70a, 70b in close contact with the adhesive parts 101, 103 of the sealing members 3, 5 and adhered to the sealing members 3, 5, and the protruding parts 51, 61 of the photoelectric conversion substrate 20 exposed from the metal electrode layers 70a, 70b are covered by and in contact with the adhesive parts 101, 103. Therefore, an anchor effect is achieved between the protruding parts 51, 61 and the adhesive parts 101, 103, and the adhesive strength between the photoelectric conversion substrate 20 and the sealing members 3, 5 can be improved.

[0053] The method for manufacturing the solar cell module 1 of the first embodiment includes a coating step of coating a photoelectric conversion substrate 20 with metal ink containing metal particles 71 having a number average particle size of 10 nm or more and less than 100 nm, and a heating step of heating the photoelectric conversion substrate 20 coated with the metal ink at a heating temperature of 100° C. or more and 180° C. or less. Therefore, compared to the conventional method, the metal electrode layers 70a, 70b can be formed at a relatively low temperature, and the manufacturing cost can be reduced.

[0054] In the above-described embodiment, the photoelectric conversion substrate 20 is formed with the pyramidal texture structures 37, 38 having the quadrangular pyramidal protrusions 51, 61, but the present invention is not limited to this. The shape of the protrusions 51, 61 may be a polygonal pyramid such as a triangular pyramid, a pentagonal pyramid, or a hexagonal pyramid, or may be a cone shape.

[0055] In the above embodiment, the photoelectric conversion substrate 20 has the textured structures 37, 38 on both main surfaces 35, 36, but the present invention is not limited to this. The textured structure 37 may be provided only on the main surface 35 on the light-receiving side.

[0056] In the above embodiment, the solar cell 10 is a crystalline silicon solar cell having a silicon semiconductor substrate 40 as a support substrate, but the present invention is not limited to this. The solar cell 10 may be another type of solar cell having a collector electrode 21 on the light receiving side. For example, the solar cell 10 may be a PERC type solar cell.

[0057] In the above-described embodiments, each component may be freely substituted or added between the respective embodiments as long as it falls within the technical scope of the present invention. [Explanation of symbols]

[0058] 1. Solar cell module 3 First sealing member 5 Second sealing member 10,10a,10b solar cell 11, 11a, 11b Wiring components 12 Conductive adhesive 20 Photoelectric conversion substrate 30 Photoelectric conversion unit 31 First transparent electrode layer (transparent conductive oxide layer) 32 Second transparent electrode layer (transparent conductive oxide layer) 35 First main surface 37 First Texture Structure 38 Second Texture Structure 51,61 Convex 52,62 Top 55,65 Recess 56,66 bottom 70a,70b Metal electrode layer (metal layer) 71 Metal particles 101,103 Adhesive part

Claims

1. A solar cell having a metal layer laminated on a photoelectric conversion substrate, the photoelectric conversion substrate has a texture structure having a plurality of convex portions on a first main surface, the metal layer is thinner than a height of the protrusion and covers a part of the protrusion; The protrusion has a top portion exposed from the metal layer.

2. The photoelectric conversion substrate has a transparent conductive oxide layer laminated on a photoelectric conversion section, The solar cell according to claim 1 , wherein the transparent conductive oxide layer constitutes the convex portion.

3. the texture structure has a plurality of recesses formed adjacent to the plurality of protrusions, The depth of the recess is 1 μm or more, the metal layer includes a plurality of metal particles; 3. The solar cell according to claim 1, wherein the metal particles have a number average particle diameter of 10 nm or more and less than 100 nm, and are filled to a height from a bottom of the recess to a height of 1 / 20 to 2 / 3 of a depth of the recess.

4. 4. The solar cell according to claim 1, wherein the metal layer surrounds the top of the protrusion when the photoelectric conversion substrate is viewed in plan.

5. A wiring member and a conductive adhesive material are included. the wiring member is connected to a portion of the metal layer via the conductive adhesive; 5. The solar cell according to claim 1, wherein a protrusion exposed from said metal layer is covered and in contact with said conductive adhesive.

6. A solar cell according to any one of claims 1 to 5, a first sealing member, and a second sealing member, the solar cell is sandwiched and sealed between the first sealing member and the second sealing member, The first sealing member has an adhesive portion, the solar cell is bonded to the first sealing member with the metal layer in close contact with the adhesive portion, a protruding portion exposed from the metal layer is covered and in contact with the adhesive portion, the solar cell module.

7. A method for producing a solar cell according to any one of claims 1 to 5, comprising the steps of: a coating step of coating the photoelectric conversion substrate with a metal ink containing metal particles having a number average particle diameter of 10 nm or more and less than 100 nm; A method for manufacturing a solar cell, comprising: a heating step of heating the photoelectric conversion substrate coated with the metal ink at a heating temperature of 100° C. or more and 180° C. or less.

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