JP2018018894A - Solar cell and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell capable of lowering the temperature thereof.SOLUTION: A solar cell includes a photoelectric conversion element 4 and a translucent member 2 disposed on the photoelectric conversion element 4 and having a surface exposed to the outside, while having a plurality of linear protrusions 7 on a surface of the translucent member 2. A solar cell also includes a photoelectric conversion element 4 and a translucent member 2 disposed on the photoelectric conversion element 4 and having a surface exposed to the outside, while having a plurality of protrusions with a height of 12 μm or higher on a surface of the translucent member 2. A solar cell module comprises a plurality of such solar cells electrically connected via wiring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solar cell.

  Solar cells are attracting attention as a means of using clean and inexhaustible energy because of the ability to directly convert sunlight into electrical energy, and expectations are increasing as a new power source to replace thermal power generation and nuclear power generation. Yes.

  In such a solar cell, a translucent member is disposed on the surface of the photoelectric conversion element, and sunlight is incident on the photoelectric conversion element via the translucent member (see, for example, Patent Document 1). .

JP 2015-29069 A

  Conventional solar cells such as Patent Document 1 have a problem that the temperature of the solar cell itself becomes high. Along with this, there was a problem that the power generation efficiency was lowered.

  An object of this invention is to provide the solar cell which can reduce temperature.

  The solar cell of the present invention includes a photoelectric conversion element and a translucent member that is disposed on the photoelectric conversion element and has a surface exposed to the outside, and a plurality of the translucent member on the surface of the translucent member. It has a linear convex part.

  The solar cell of the present invention includes a photoelectric conversion element and a translucent member that is disposed on the photoelectric conversion element and has a surface exposed to the outside, and is provided on the surface of the translucent member. And a plurality of convex portions having a height of 12 μm or more.

  Furthermore, the solar cell of the present invention includes a photoelectric conversion element, a translucent member disposed on the photoelectric conversion element, a translucent member disposed on the translucent member and having a surface exposed to the outside. And a plurality of linear protrusions on the surface of the translucent member on the side of the covering member, and the covering member has an emissivity of 80 in the infrared region having a wavelength of 8 μm or more. % Of material.

  Moreover, the solar cell of the present invention includes a photoelectric conversion element, a translucent member disposed on the photoelectric conversion element, and a translucent member disposed on the translucent member and having a surface exposed to the outside. And having a plurality of convex portions with a height of 12 μm or more on the surface of the translucent member on the side of the covering member, and the covering member has an infrared region with a wavelength of 8 μm or more. It is characterized by comprising a material having an emissivity of 80% or more.

  The solar cell module of the present invention is characterized in that a plurality of the above-described solar cells are electrically connected via wiring.

  According to the present invention, the temperature of the solar cell itself can be lowered.

It is a schematic sectional drawing which shows the lamination | stacking state of a solar cell. (A) is a perspective view showing a translucent member, (b) is a cross-sectional view taken along the line AA ′ of (a), and (c) is a cross-sectional view of the translucent member with the formation cycle of the linear protrusions changed. It is. It is a simulation result which shows the relationship between the wavelength and emissivity in the translucent member which consists of glass, (a) is when the exposed surface of a translucent member is flat, (b) is the exposed surface of a translucent member. This is a case where a linear convex portion as shown in FIG. It is a simulation result which shows the emissivity at the time of changing the height and formation period of the linear convex part in the exposed surface of a translucent member. The solar cell module is shown, in which (a) is a schematic cross-sectional view, and (b) is a cross-sectional view taken along line B-B 'of (a). (A) is sectional drawing which shows the solar cell which has a coating member on the surface of a translucent member, (b) is sectional drawing which shows the other example of the solar cell which has a coating member.

  One embodiment of a solar cell will be described with reference to FIG. In the solar cell of the present embodiment, a substrate-like translucent member 2, a photoelectric conversion element 4, a sealing layer 5, and a cover layer 6 are sequentially laminated. Note that electrodes (not shown) are provided on both main surfaces of the photoelectric conversion element 4. Further, a wavelength conversion layer may be interposed between the translucent member 2 and the photoelectric conversion element 4, and furthermore, a reflection layer may be interposed between the sealing layer 5 and the cover layer 6. good. 1 describes the case where the photoelectric conversion element 4 is covered with the sealing layer 5 except for the upper surface thereof, the entire surface of the photoelectric conversion element 4 may be covered with the sealing layer 5.

  In such a solar cell, light in a wavelength region that can be converted into electric energy by the photoelectric conversion element 4 in the sunlight 1 incident from the translucent member 2 side, that is, light in an effective wavelength region is translucent. It passes through the member 2 and enters the photoelectric conversion element 4 and is converted into electric energy.

  The photoelectric conversion element 4 has electrodes provided on both main surfaces of a substrate having photovoltaic power. The substrate is preferably in the form of a plate having a thickness of 0.3 to 0.4 mm, for example, but may take a form such as a spherical shape or a thin film shape. In addition to silicon-based materials such as single crystal silicon, polycrystalline silicon, and amorphous silicon, any of CIGS compound-based materials, CdTe compounds, organic-based materials, dye-sensitized materials, and the like may be used for the base material.

  Sunlight is composed of light having various wavelengths in the region of 300 to 3000 nm, and depending on the wavelength, the visible light region (the lower bound is 360 to 400 nm, the upper bound is 760 to 830 nm), and the lower bound Are also classified into a near-ultraviolet region having a short wavelength, a near-infrared region having a wavelength longer than the upper limit, and an infrared region.

  The wavelength region where the conversion efficiency of the photoelectric conversion element 4 is high, that is, the effective wavelength region is, for example, 400 to 1100 nm for single crystal and polycrystalline silicon solar cells, 400 to 1200 nm for CIGS compound-based and CdTe compound-based solar cells, amorphous silicon, organic In systems and dye-sensitized solar cells, it is known to be 350-750 nm, most of which overlaps the visible light region.

In this embodiment, as shown in FIG. 1 and FIGS. 2A and 2B, a plurality of linear protrusions 7 are provided on the surface exposed to the outside of the translucent member 2. . The translucent member 2 is made of glass containing SiO ₂ , and linear linear convex portions 7 are formed on the surface of the translucent member 2. If the cross section of the linear convex portion 7 is an isosceles triangle as shown in FIG. 2B, the linear convex portion 7 means that the top and bottom sides of the cross section extend in the same direction. It is not limited to the case where it extends linearly as shown in 2 (a).

  Thus, since the linear convex part 7 is formed in the exposed surface of the translucent member 2, the infrared rays inside a solar cell can be radiated | emitted outside effectively, the internal temperature of a solar cell is lowered | hung, thereby generating electric power The amount can be improved. Furthermore, since infrared radiation is not heat transfer or radiation to the atmosphere but radiation to the universe, the greenhouse effect can be reduced.

  Moreover, rainwater becomes easy to flow by arrange | positioning the linear linear convex part 7 so that it may extend in the direction in which a solar cell inclines.

  As shown in FIG. 2B, the linear protrusion 7 has a height h of, for example, 12 μm or more. Thereby, the infrared rays inside the solar cell can be effectively radiated to the outside, the temperature inside the solar cell can be lowered, and thereby the amount of power generation can be improved.

  The formation period w of the plurality of linear protrusions 7 is set to 8 μm or less, for example. Thereby, the infrared rays of the solar cell can be effectively radiated to the outside, the temperature inside the solar cell can be lowered, and thereby the amount of power generation can be improved. In addition, the formation period w of the linear convex part 7 means that when the plurality of linear convex parts 7 are continuously formed in the width direction B as shown in FIG. This corresponds to the width of the bottom of the linear protrusion 7.

  In addition, each figure of this application is typical, and the magnitude | size of an unevenness | corrugation and the thickness of each layer do not reflect actual dimensional relationships.

  2A and 2B, a plurality of linear linear convex portions 7 are continuously provided in the width direction of the linear convex portion 7 on the surface exposed to the outside of the translucent member 2. Although the case where it formed was demonstrated, as shown in FIG.2 (c), you may form the several linear convex part 7 spaced apart with a fixed space | interval.

  Furthermore, although the cross section of the linear convex portion 7 in FIGS. 2A and 2B has a cone shape in which the width w decreases toward the tip, the shape of the tip in the case of the cone shape is pointed. It may be rounded or rounded.

  The linear convex part 7 of the translucent member 2 can be formed using a mold at the time of molding. Further, it can be formed by grinding the surface of the translucent member 2.

  The effect of this embodiment was verified using simulation. The following conditions were used for the simulation. Since light is a type of electromagnetic wave, the Finite-Difference Time-Domain (FDTD) method was used for electromagnetic wave simulation.

  The FDTD method is a method in which time is divided into appropriate increments and the space is subdivided (discretized) into rectangular parallelepipeds. In this simulation, the space was subdivided into cubes with sides of 200 nm. The time increment was about 0.4 fs. In the simulation, a transient phenomenon of about 4 ps in total was analyzed.

The propagation of the electromagnetic wave over about 4 ps was Fourier transformed, and the emissivity for each wavelength was calculated. The outgoing light is infrared light having a wavelength of 6 to 15 μm. Moreover, the linear convex part 7 is made into the linear linear convex part 7 as shown to Fig.2 (a) (b), the height h is 6 micrometers, the period w is 9 micrometers, and the linear convex part 7 is made into that The shape was continuous in the width direction B. The results are shown in FIG. In FIG. 3, the horizontal axis represents the wavelength of infrared light, and the vertical axis represents the emissivity.

  From FIG. 3, when the linear convex part 7 is formed on the surface of the translucent member 2 made of glass containing Si (FIG. 3B), the surface of the translucent member 2 is flat. Compared with (FIG. 3 (a)), the emissivity of infrared light having a wavelength of 8 to 11 μm is increased, and as a result, the temperature of the solar cell when the surface of the translucent member 2 is flat is 54. In contrast to the temperature of 3 ° C., the temperature of the solar cell when the linear protrusion 7 is formed on the surface of the translucent member 2 is 52.5 ° C., and the internal temperature of the solar cell is reduced. .

  Furthermore, the simulation is performed by changing the height h of the linear convex portion 7 as shown in FIGS. 2A and 2B in the range of 6 to 16 μm and the formation period w in the range of 6 to 16 μm. The results are shown in FIG. From FIG. 4, when the height h of the linear protrusion 7 is 12 μm or more, and the formation period w of the plurality of linear protrusions 7 is 8 μm or less, the emission of infrared light having a wavelength of 8 to 11 μm. It can be seen that the rate is high.

  For example, the temperature of the solar cell in the case where the linear protrusion 7 having a period w of 9 μm and a height h of 6 μm is formed is 52.5 ° C., and the linear protrusion having a period w of 6 μm and a height h of 16 μm. The temperature of the solar cell when the portion 7 is formed is 49.1 ° C., and the internal temperature is lower than the temperature of the solar cell 54.3 ° C. when the surface of the translucent member 2 is flat. I understand that.

  Thereby, it turns out that the infrared rays of a solar cell can be radiated | emitted effectively outside, the temperature inside a solar cell can be lowered | hung, and this can improve the electric power generation amount by this.

  Moreover, by forming the linear convex part 7 in the surface of the translucent member 2, for example, a contact area with the fallen leaf which fell on the surface of the translucent member 2 reduces, it becomes easy to fall, and translucency The shielding object which shields sunlight, such as a fallen leaf, does not remain on the surface of the member 2 for a long time, and can maintain high power generation performance. In particular, by forming the linear protrusions 7 on the surface of the translucent member 2 so that the solar cell extends in a downwardly inclined direction, it is possible to induce the fall of a shielding object such as a fallen leaf.

  Furthermore, even if a shielding object such as a fallen leaf is located on the surface of the translucent member 2, sunlight is incident obliquely from the linear convex portion 7, and the sun is applied to the photoelectric conversion element 4 located behind the shielding object. The incidence of light makes it possible to reduce the decrease in power generation performance. In order to obtain such an effect by the shielding object, it is desirable that the ratio of the height h / cycle w of the linear protrusion 7 is 0.5 or more.

  The translucent member 2 protects each element constituting the solar cell such as the photoelectric conversion element 4, and is preferably made of glass containing Si from the viewpoint of weather resistance and mechanical strength. The thickness is preferably about 3 to 5 mm.

  The electrodes provided on both main surfaces of the photoelectric conversion element 4 are made of a conductive material, such as a metal material such as Ag, Ni, Cu, and Al, an alloy material such as solder, a carbon material, indium tin oxide (ITO ) And other conductive oxide materials, and conductive resin materials containing these as fillers.

  For the sealing layer 5, for example, a resin mainly composed of ethylene-vinyl acetate copolymer is used, and polyvinyl butyral (PVB) or silicone is used in terms of adhesion to the photoelectric conversion element 4, durability, and workability. Etc. may be contained at a ratio of 10% by mass or less. The total thickness of the wavelength conversion layer and the sealing layer is preferably about 0.4 to 1 mm.

  For the cover layer 6, a fluorine resin sheet having weather resistance in which an aluminum foil is sandwiched so as not to transmit moisture, a polyethylene terephthalate (PET) sheet on which alumina or silica is deposited, and the like are preferably used.

  In addition, although the said form demonstrated the solar cell which has the linear convex part 7, it does not need to be linear. In this case, it is desirable that the convex portion has a height of 12 μm or more.

  Fig.5 (a) is the schematic sectional drawing shown about the solar cell module which is one Embodiment of this invention, and the plate-shaped translucent member 2, wavelength conversion layer from the light-receiving surface side into which sunlight 1 injects. 13, a plurality of photoelectric conversion elements 4, a sealing layer 5, a reflective layer 16, and a cover layer 6 are laminated in this order, and an electrode (not shown) on the translucent member 2 side that is the light receiving surface of one photoelectric conversion element 4. ) And an electrode (not shown) on the reflective layer 6 side of the other photoelectric conversion element 4 are connected by an interconnector 9.

  In addition, in the cross-sectional view taken along the line BB ′ in FIG. 5A as viewed from the light-transmitting member 2 side that is the light-receiving surface side in FIG. 5B, the connection state of the plurality of photoelectric conversion elements 4 in FIG. Is shown. In the present embodiment, one wavelength conversion layer 13 is provided on the light transmissive member 2 side with respect to the plurality of photoelectric conversion elements 4, but each of the plurality of photoelectric conversion elements 4 is individually provided on the light transmissive member 2 side. The wavelength conversion layer 13 can also be provided. For the interconnector 9, a copper foil or the like coated with solder is preferably used.

  In FIG. 1, although the form which the translucent member 2 was exposed outside was demonstrated, as shown in FIG. 6, it exposed outside so that the linear convex part 7 might be covered on the surface of the translucent member 2 A covering member 11 having a surface may be disposed. The covering member 11 is made of a material having a high infrared emissivity. In other words, the covering member 11 is formed of a material having an emissivity of 80% or more in an infrared region having a wavelength of 8 μm or more.

  As mentioned above, although the solar cell and the solar cell module which are examples of embodiment of this invention were demonstrated, this invention is not limited to these embodiment, About what was variously changed in the range which does not deviate from this invention. Can be applied.

DESCRIPTION OF SYMBOLS 1 ... Sunlight 2 ... Translucent member 4 ... Photoelectric conversion element 5 ... Sealing layer 6 ... Cover layer 7 ... Linear convex part

Claims (8)

  A photoelectric conversion element and a translucent member that is disposed on the photoelectric conversion element and has a surface exposed to the outside, and have a plurality of linear protrusions on the surface of the translucent member A solar cell characterized by.   The solar cell according to claim 1, wherein a height of the plurality of linear protrusions is 12 μm or more.   3. The solar cell according to claim 1, wherein a formation period of the plurality of linear protrusions is 8 μm or less.   The solar cell according to claim 1, wherein the translucent member is made of a material having an emissivity of 80% or more in an infrared region having a wavelength of 8 μm or more.   A photoelectric conversion element and a translucent member disposed on the photoelectric conversion element and having a surface exposed to the outside; and a plurality of a plurality of light transmissible members having a height of 12 μm or more on the surface of the translucent member A solar cell having a convex portion.   A photoelectric conversion element, a translucent member disposed on the photoelectric conversion element, and a translucent covering member disposed on the translucent member and having a surface exposed to the outside The translucent member has a plurality of linear convex portions on the surface of the covering member, and the covering member is made of a material having an emissivity of 80% or more in an infrared region having a wavelength of 8 μm or more. A solar cell.   A photoelectric conversion element, a translucent member disposed on the photoelectric conversion element, and a translucent covering member disposed on the translucent member and having a surface exposed to the outside A material having a plurality of convex portions having a height of 12 μm or more on the surface of the translucent member on the coating member side, wherein the coating member has an emissivity of 80% or more in an infrared region having a wavelength of 8 μm or more. A solar cell comprising:   A solar cell module comprising a plurality of the solar cells according to any one of claims 1 to 7 electrically connected via wiring.