TWI814224B - Photovoltaic module with light guide structure - Google Patents

Abstract

A photovoltaic module with light guide structure is provided to solve the problem of causing light to escape and reducing power generation of the array gap of the conventional photovoltaic module. The photovoltaic module includes a plurality of solar cells arranged on the same plane in an array, and a plurality of light guide structures. Each of the light guide structures is located in a gap between two adjacent solar cells. Each of the light guide structures is coverd by a high refractive index materal with a low refractive index materal. The high refractive index materal has a higher refractive index than the low refractive index materal. When a light irradiates the photovoltaic module, a part of the light irradiates the plurality of light guide structures to guide the light to the adjacent solar cells. Two cover layers are respectively located on the upper and lower sides of the plurality of solar cells and the plurality of light guide structures.

Description

Solar module with light guide structure

The present invention relates to a photoelectric conversion device, in particular to a solar module with a light guide structure that improves the utilization rate of sunlight to increase power generation.

Solar energy is a rapidly developing renewable energy source. Compared with water power and wind power, which have high application thresholds and are limited by installation locations, solar power generation devices can be installed in residences and are easily popularized. In addition, common solar power generation systems utilize the photoelectric effect. The material absorbs photon energy and generates free electrons that overflow from the surface of the material. Accordingly, when a solar cell (Photovoltaic Cell) made of semiconductor material is irradiated by sunlight or other electromagnetic radiation, it can generate a voltage at the semiconductor junction or the combination with the metal. and current.

A general solar module (Photovoltaic Module) is composed of the above-mentioned several solar cells arranged in an array, and the several solar cells are electrically connected to each other to collect the generated current. However, between adjacent solar cells There is an arrangement gap of 2 to 10 mm and a busbar (finger/busbar) used to guide current. These areas are not covered with optoelectronic semiconductor materials, and of course cannot absorb sunlight and convert it into electrical energy. Conventional solar modules add reflective structures between solar cells to reflect light that originally escapes in the gaps to the solar cells to increase power generation. However, processing reflective structures on solar modules increases manufacturing difficulty. and cost, and may damage the structural strength of the solar module. In addition, the reflective structure only reflects light randomly, making it difficult to guide the light to the solar cell or its center, causing the reflected light to appear on the surface of the solar cell. The surface is scattered and uneven, and the total power generation capacity of the conventional solar module cannot be effectively increased.

In view of this, conventional solar modules still need to be improved.

In order to solve the above problems, the purpose of the present invention is to provide a solar module with a light guide structure, which can increase the total power generation capacity.

A secondary object of the present invention is to provide a solar module with a light guide structure, which can reduce manufacturing difficulty and production costs.

Another object of the present invention is to provide a solar module with a light guide structure that can avoid damage to the module structure caused by processing.

Directionality or similar terms used throughout the present invention, such as "upper (top)", "lower (bottom)", "inner", "outer", "side", etc., mainly refer to the directions of the attached drawings, each of which Directionality or similar terms are only used to assist in explaining and understanding the embodiments of the present invention, but are not intended to limit the present invention.

The use of the quantifier "a" or "an" in the elements and components described throughout the present invention is only for convenience of use and to provide a common sense of the scope of the present invention; in the present invention, it should be interpreted as including one or at least one, and single The concept of also includes the plural unless it is obvious that something else is meant.

The solar module with a light guide structure of the present invention includes: several solar cells arranged in an array on the same plane; several light guide structures, each light guide structure is located between two adjacent solar cells. gap, each light guide structure is made of a high refractive index material covering a low refractive index material. The refractive index of the high refractive index material is greater than the low refractive index material. The low refractive index material forms several columns in parallel. The cross-section of each columnar structure is a geometric shape, and the geometric shape has at least one bevel facing the adjacent solar cell. When a light shines on the sun In the energy module, part of the light irradiates the plurality of solar cells, and another part of the light irradiates the plurality of light guide structures, and total reflection occurs on the side of each columnar structure where the hypotenuse extends, And the light will be refracted and reflected several times in each light guide structure, and then be guided to adjacent solar cells; two protective films are respectively attached to the solar cells and the light guide structures. On the upper and lower surfaces, the two protective films encapsulate the light guide structures and are fixed between the solar cells; and the two covering layers are respectively located on the solar cells and the light guide structures. On the lower two sides, each covering layer is attached to the outer surface of each protective film. The light penetrates at least one of the covering layers. The light enters the solar cell after total reflection at the interface between the covering layer and the air. piece.

Accordingly, in the solar module with a light guide structure of the present invention, by arranging the light guide structure in the gap of the solar cell array, the light irradiated on the light guide structure reaches the solar cells after two total reflections. The system can guide the light that would otherwise escape through the gap to the solar cells to increase the luminous flux that the solar module can receive and the total amount of power generated. In addition, the light guide structure can be mass-produced in advance and installed on the solar module. During the packaging process, it is placed between several solar cells and does not require processing of reflective structures on the solar module. This has the effect of reducing manufacturing difficulty, saving costs and maintaining structural strength.

Wherein, the geometric shape is a right-angled triangle, the hypotenuse is the opposite side of the right angle, and the two ends of the hypotenuse are the other two angles of the right-angled triangle, which are a first included angle and a second included angle, and the first included angle is relatively close to the The light incident end, and the second included angle is relatively far away from the light incident end, the first included angle is 42 degrees to 46 degrees, and the second included angle is the supplementary angle of the first included angle. In this way, the other side of each columnar structure opposite to the reflective surface is a vertical plane, which can prevent the light from escaping back into the air due to secondary total internal reflection, and has the effect of increasing the rate of light being directed to the solar cell.

Wherein, the geometric shape is a parallelogram, a rhombus, an upper half triangle combined with a lower half triangle, or an upper half triangle combined with a lower half semicircle. In this way, each columnar structure has more than one reflective surface, and the light incident from below the solar module can be guided, and has the ability to collect and disperse light. Radiation light is used to convert electrical energy.

Wherein, the plurality of columnar structures formed by the low refractive index material are closely arranged on the same plane, and the plane is parallel to the plane on which the plurality of solar cells are arranged, and the extension direction of each columnar structure is parallel to the adjacent one. the edge of the solar cell. In this way, after the light irradiating the gap is reflected by the light guide structure, it can be irradiated uniformly on the solar cell sheet, which has the effect of uniform luminous flux and photoelectric conversion.

The width of the light guide structure is 2 mm to 10 mm, and the width of each columnar structure is 0.125 mm to 1 mm. In this way, the size of the light guide structure can be adjusted according to the specifications of the solar module to fill the gaps between the cells and includes several columnar structures, which is convenient for manufacturing and installation.

Wherein, the two covering layers are light-transmitting glass, and the refractive index of each covering layer is greater than or equal to the high refractive index material. In this way, light can be emitted outward through the interface between the high refractive index material and the two covering layers, and total reflection is formed at the interface between the covering layer and the air, which has the effect of guiding the reflected light to the center of the cell piece. .

Wherein, the covering layer of the upper layer is made of light-transmitting glass and directly faces the light irradiation, the covering layer of the lower layer is a back plate, and the refractive index of the covering layer of the upper layer is greater than or equal to the high refractive index material. In this way, the light that escapes to the lower layer can be reflected back to the solar cell through the backsheet, which has the effect of improving light utilization efficiency.

Wherein, the two protective films are heat-curing hot-melt adhesive films. In this way, after curing, the two protective films have high light transmittance, impact resistance and flexibility, can protect the solar cells from environmental damage, and can also encapsulate and fix the light guide structures in the correct position. , which has the effect of extending the service life of solar modules.

1: Solar cells

2:Light guide structure

21:High refractive index materials

22: Low refractive index materials

3: Covering layer

4: Protective film

H: hypotenuse

α: first included angle

β: the second included angle

L:Light

[Figure 1] A combined perspective view of a preferred embodiment of the present invention.

[Figure 2] Cross-sectional view along line A-A in Figure 1.

[Picture 3] An enlarged view of the local structure of area B shown in Figure 2.

In order to make the above and other objects, features and advantages of the present invention more obvious and understandable, preferred embodiments of the present invention are illustrated below and described in detail with reference to the accompanying drawings; in addition, the same symbols are used in different drawings. are considered to be the same and their description will be omitted.

Please refer to Figures 1 and 2, which is a preferred embodiment of a solar module with a light guide structure of the present invention, which includes a plurality of solar cells 1, a plurality of light guide structures 2 and two covering layers 3, each The light guide structure 2 is located in the gap between two adjacent solar cells 1 , and the two covering layers 3 are respectively located on the upper and lower surfaces of the solar cells 1 and the light guide structures 2 .

The several solar cells 1 are used to convert light energy into electrical energy. Since the power and voltage value that a single solar cell 1 can convert is limited, in order to meet the power demand, the several solar cells are usually arranged in an array. 1 on the same plane and placed in a location with sufficient and uniform light flux to stabilize the power generation of each solar cell 1, and then combine the power generation of the several solar cells 1 in series and parallel, and the In areas where there are array gaps and bus wires between the solar cells 1, the solar cells 1 cannot directly absorb light energy.

Please refer to Figures 2 and 3. The light guide structures 2 are respectively located in the gaps between the solar cells 1. Each light guide structure is covered with a low refractive index material 21 by a high refractive index material. Material 22. The refractive index of the high refractive index material 21 is greater than the low refractive index material 22. The high refractive index material 21 can be glass, polymethyl methacrylate (PMMA), or epoxy resin. (Epoxy) or liquid optical glue (Liquid Optically Clear Adhesive (LOCA), etc., the low refractive index material 22 can be a cavity (air or vacuum) or polydimethylsiloxane (PDMS), etc., the low refractive index material 22 forms several columns in parallel. The cross-section of each columnar structure is a geometric shape, and the geometric shape has at least one hypotenuse H facing the adjacent solar cell sheet 1, as shown in Figure 3. In this embodiment, the geometric shape is The shape is a right-angled triangle for illustration. The geometric shape may also be a parallelogram, a rhombus, an upper half triangle combined with a lower half triangle, an upper half triangle combined with a lower half semicircle, etc. The invention is not limited thereto. If the geometric shape is a right-angled triangle, the hypotenuse H is the opposite side of the right angle. The two ends of the hypotenuse H are the other two angles of the right-angled triangle, which are a first included angle α and a second included angle β. The first included angle α The first included angle β is a complementary angle to the second included angle β (the sum of the angles is 90 degrees). The first included angle α is relatively close to the light incident end, and the second included angle β is relatively far away from the light incident end. The first included angle α can be 42 degrees to 46 degrees, preferably 42 degrees; the second included angle β can be 44 degrees to 48 degrees, preferably 48 degrees.

In addition, the plurality of columnar structures formed by the low refractive index material 22 are preferably closely arranged on the same plane without overlapping each other, and the plane is preferably parallel to the plane on which the plurality of solar cells 1 are arranged, and , the extension direction of each columnar structure is preferably parallel to the edge of the adjacent solar cell 1, so that the light irradiating the gap can be completely collected, and the guided light can be uniformly irradiated on the solar cell 1. Each columnar structure uses the side surface where the hypotenuse H extends as a reflective surface. The reflective surface is the interface between the high refractive index material 21 and the low refractive index material 22. Due to the refraction of the high refractive index material 21 The refractive index is greater than that of the low refractive index material 22, and the incident light system at a specific angle can form total reflection on the reflective surface.

The width of each of the above-mentioned columnar structures can be 0.125 mm ~ 1 mm, and the width of the light guide structure 2 is 2 mm ~ 10 mm. Taking a width of 10 mm as an example, the light guide structure 2 can contain up to 80 0.125 mm columnar structure, and can contain at least 10 columnar structures of 1 mm.

The light guide structure 2 can be manufactured by soft lithography technology. The high refractive index material 21, such as liquid optical glue, is coated on a mold with a plurality of columnar structures and irradiated with ultraviolet light. The liquid optical glue is cured, and after demoulding, glue is applied to the convex parts to connect the flat films made of the same material. After curing again, a light guide structure 2 with a columnar cavity is formed, and the low refractive index material 22 is air.

The two covering layers 3 can be both upper and lower layers of light-transmitting glass, or the upper layer (front, light source irradiation surface) can be made of light-transmitting glass, and the lower layer (back) can be a solar back panel. The two covering layers 3 can be used for Prevent external environmental damage such as high temperature, moisture, acid corrosion and impact from causing damage to each solar cell 1. In addition, each covering layer 3 is light-transmitting glass, so that light can pass through the glass and its refractive index is greater than that of the external environment. Air, when light is emitted from between the two covering layers 3, the interface between the covering layer 3 and the air changes from a dense medium of light to a rare medium of light, so that light at a specific angle can pass through the interface. Form total reflection. The refractive index of each covering layer 3 may be greater than or equal to the high refractive index material 21; the refractive index of the low refractive index material 22 may be greater than or equal to air.

The solar module of the present invention can also have two protective films 4. The two protective films 4 are closely attached to the upper and lower surfaces of the plurality of solar cells 1 and the plurality of light guide structures 2. The two covering layers 3 Then attached to the outer surface of the two protective films 4, the two protective films 4 can be heat-curing hot melt adhesive films, such as: acetic acid/vinyl acetate copolymer (Ethylene Vinyl Acetate, EVA), the two protective films 4 are After hot pressing, metal, glass and plastic can be well bonded, and the cured protective films 4 have high light transmittance, impact resistance and flexibility, and can protect the solar cells 1 from environmental damage. The plurality of light guide structures 2 can also be packaged and fixed in the correct position, and the two protective films 4 are completely transparent and will not affect the incidence of light, which can extend the service life of the solar module and improve the power generation efficiency.

Please refer to Figures 2 and 3. When a light L irradiates the solar module and passes through the covering layer 3 and the protective film 4, the light L scattered on the solar cells 1 can The light L that is converted into electrical energy and dispersed in the gaps between the solar cells 1 will be refracted and reflected several times in each light guide structure 2 to be redirected to the adjacent solar cells 1 , the light reflected by the reflective surface of the columnar structure closest to each solar cell 1 (the side where the hypotenuse H extends) can be completely reflected again at the interface between the covering layer 3 and the air. Entering the solar cell 1; as shown in Figure 3, the light reflected by the reflective surfaces of other columnar structures must repeatedly pass through several columnar structures before reaching the covering layer 3 and the solar cell in sequence. Chip 1, the light guide structure 2 can increase the light flux received by the solar cell chip 1. Please refer to Table 1, which shows the radiant flux (Radiant Flux) that a solar module with a light guide structure of the present invention can convert to incident light at different angles compared to a solar module without a light guide structure.

It can be seen from Table 1 that when light shines directly on the solar module, the power that can be received and converted is a maximum value. Using a light guide structure can increase the power by another 13.31%. However, the angle of sunlight changes periodically with time. , and the closer to sunrise or sunset, the greater the deflection angle of the illumination, resulting in the smaller the corresponding power that can be received. At this time, using a light guide structure can still increase the power, but the greater the deflection angle of the illumination, the lower the power The smaller the proportion that can be improved. In summary, based on a whole day's sunshine statistics, the use of light guide structures can increase the power generation of solar modules by 5.77%.

To sum up, the solar module with a light guide structure of the present invention disposes the light guide structure in the gap of the solar cell array, so that the light irradiated on the light guide structure reaches the solar cell after two total reflections. The light guide structure can guide the light that would otherwise escape through the gap to the solar cells to increase the luminous flux that the solar module can receive and the total power generation. In addition, the light guide structure can be mass-produced in advance and installed on the solar module. During the packaging process of the group, it is placed between several solar cells. There is no need to process reflective structures on the solar module, which has the effect of reducing manufacturing difficulty, saving costs and maintaining structural strength.

Although the present invention has been disclosed using the above-mentioned preferred embodiments, they are not intended to limit the invention. Anyone skilled in the art can make various changes and modifications to the above-described embodiments without departing from the spirit and scope of the invention. The technical scope protected by the invention, therefore, the protection scope of the invention shall include all changes within the literal and equivalent scope described in the appended patent application scope.

1: Solar cells

2:Light guide structure

3: Covering layer

4: Protective film

L:Light

Claims (8)

A solar module with a light guide structure, including: several solar cells arranged in an array on the same plane; several light guide structures, each light guide structure is located in the gap between two adjacent solar cells , each light guide structure is made of a high refractive index material covering a low refractive index material. The refractive index of the high refractive index material is greater than the low refractive index material. The low refractive index material forms several columnar structures in parallel. , the cross-section of each columnar structure is a geometric shape, and the geometric shape has at least one bevel facing the adjacent solar cells. When a light shines on the solar module, part of the light shines on the several solar cells. Cell sheet, the other part of the light irradiates the several light guide structures, and is totally reflected on the side of each columnar structure where the hypotenuse extends, and the light will be refracted several times at each of the light guide structures. and reflection, and are guided to adjacent solar cells; two protective films are respectively attached to the upper and lower surfaces of the plurality of solar cells and the plurality of light guide structures, and the two protective films encapsulate the plurality of guide structures. The light structure is fixed between the solar cells; and two covering layers are respectively located on the upper and lower surfaces of the solar cells and the light guide structures, and each covering layer is attached to each protective film. On the outer surface of the solar cell, the light penetrates at least one of the covering layers. The light enters the solar cell sheet after total reflection at the interface between the covering layer and the air. As claimed in claim 1, the solar module with a light guide structure, wherein the geometric shape is a right-angled triangle, the hypotenuse is the opposite side of the right angle, and the two ends of the hypotenuse are the other two angles of the right-angled triangle, which is a first The included angle and a second included angle, the first included angle is relatively close to the light incident end, and the second included angle is relatively far away from the light incident end, the angle of the first included angle is 42 degrees to 46 degrees, and the second included angle is the The supplementary angle of an included angle. Such as the solar module with a light guide structure of claim 1, wherein the geometric shape is a parallelogram, a rhombus, an upper half triangle combined with a lower half triangle, or an upper half triangle combined with a lower half semicircle. The solar module with a light guide structure as claimed in claim 1, wherein the plurality of columnar structures formed by the low refractive index material are closely arranged on the same plane, and the plane is parallel to the arrangement of the plurality of solar cells. plane, the extension direction of each columnar structure is parallel to the edge of the adjacent solar cell sheet. For example, the solar module with a light guide structure according to claim 1, wherein the width of the light guide structure is 2 mm to 10 mm, and the width of each columnar structure is 0.125 mm to 1 mm. As claimed in claim 1, the solar module with a light guide structure, wherein the two covering layers are light-transmitting glass, and the refractive index of each covering layer is greater than or equal to the high refractive index material. The solar module with a light guide structure of claim 1, wherein the upper covering layer is light-transmitting glass and directly faces the light irradiation, the lower covering layer is a backsheet, and the refractive index of the upper covering layer Greater than or equal to the high refractive index material. As claimed in claim 1, the solar module with a light guide structure, wherein the two protective films are thermally cured hot melt adhesive films.

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