WO2014014294A1

WO2014014294A1 - Thin film solar cell module, using sub-module

Info

Publication number: WO2014014294A1
Application number: PCT/KR2013/006452
Authority: WO
Inventors: 김진혁; 김진웅; 유홍
Original assignee: 에스케이이노베이션 주식회사
Priority date: 2012-07-18
Filing date: 2013-07-18
Publication date: 2014-01-23

Abstract

The present invention relates to a thin-film solar cell module using a sub-module and to a method for producing the solar cell module. More specifically, the present invention relates to a thin-film solar cell module wherein small-surface-area sub-modules are constituted in an array in order to provide a solution for decreased efficiency due to reduced uniformity in thin films when producing thin-film solar cell modules or panels of large surface area, and the present invention also relates to a method for producing the solar cell module.

Description

Thin Film Solar Cell Module Using Submodule

The present invention relates to a thin-film solar cell module using a sub-module, and more particularly, in order to solve the reduction in efficiency caused by the decrease in uniformity of the thin film when manufacturing a large-area thin-film solar cell module or panel, It relates to a thin-film solar cell module and a manufacturing method by arranging the sub-modules of the.

A solar cell is a device that converts light into electricity using the properties of a semiconductor. The solar cell is formed by joining a P (positive) type semiconductor and a N (negative) type semiconductor. When light such as solar light shines on a solar cell, electric charges move inside to form a potential difference (called photovoltaic power) between the P pole and the N pole, and when a load is connected between them, a photoelectric effect causes current to flow. Electric energy is generated.

Currently produced solar cells are largely divided into a substrate type and a thin film type, the substrate type is to use a semiconductor material itself such as silicon as a substrate, the thin film type is formed in the form of forming a semiconductor in a thin film form on a substrate such as glass or the like. In the case of the substrate type, there is a problem in that the efficiency is excellent, but there is a limit in reducing the thickness, and the cost of the substrate is high, resulting in a material cost increase during production. Thin film solar cells, on the other hand, are somewhat less efficient, but are more advantageous in terms of productivity, economy, etc., and have many advantages, such as the advantage of using a transparent material for a wide range of applications. have.

Generally, a thin film solar cell includes a substrate, an electrode layer formed on the substrate, an absorbing layer that absorbs light to generate electricity, a transmission layer through which light passes, and a superstrate covering and protecting the various layers as described above. It is made to include. At this time, the absorption layer is a P-type semiconductor, the transmission layer is an N-type semiconductor, the absorption layer and the transmission layer has a P-N diode structure to generate electricity.

In such a thin-film solar cell, the voltage range generated in the P-N diode structure of the absorption layer and the transmission layer is generally known to be about 0.5 to 0.7V. However, in order to be commercially available, a higher voltage output must be implemented. For this purpose, in general, a thin film solar cell adopts a configuration in which unit cells having the structure described above are connected in series to increase an output voltage.

In the case of a substrate type solar cell, since the silicon substrate itself serves as an absorbing layer, monolithic integration is difficult and discrete integration is inevitably inevitable. On the other hand, in the case of a thin film solar cell, since the substrate and the absorber layer are separate, the electrode layer, the absorber layer, and the transmissive layer can be scribed on the same substrate, respectively, thereby providing a single integration. As described above, a technique for forming a solar cell module by forming a semiconductor layer on the same substrate and scribing the same is disclosed in Korean Patent Publication No. 2012-0047678 ("Thin Film Solar Cell Module and Manufacturing Method thereof", 2012.05.14) and the like. have.

On the other hand, as compared with the efficiency of the unit cell of the thin-film solar cell, it is well known to those skilled in the art that the larger the area of the module, the greater the efficiency tends to decrease. At the unit cell level, the unit cell with 0.5 cm ² area announced by the German ZSW research center in 2011 achieved the world's highest efficiency with 20.3% efficiency. At the module level, 30X30 cm ² area announced by Solar Frontier of Japan In the case of a large-area module (or panel) having an area of more than 1 m ² , a module having an efficiency of 17.8% has an average efficiency of not exceeding 14%.

As solar cells become larger in area, efficiency decreases, such as edge loss due to scribing loss, bus-bar, isolation, and the like. . Among them, the most important factor of efficiency deterioration is that as the solar cell has a large area, it is difficult to secure and manufacture uniformity as a whole. In other words, it is difficult to produce a condition that can achieve the optimum efficiency evenly implemented throughout the large area.

At present, the problem of securing uniformity in large-area solar cells is gradually improving due to the development of new equipment and improved process capability. However, the development speed is very slow. In order to solve the problem of uniformity in manufacturing large-area solar cells, there is a need for finding a new perspective from the conventional direction.

[Preceding technical literature]

[Patent Documents]

Korean Patent Publication No. 2012-0047678 ("Thin Film Solar Cell Module and Manufacturing Method", 2012.05.14)

Accordingly, the present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to reduce the efficiency caused by the uniformity of the thin film when manufacturing a large-area thin-film solar cell module or panel In order to solve the problem is to provide a thin-film solar cell module made by arranging sub-modules of a small area.

Thin-film solar cell module using a sub-module according to an embodiment of the present invention for achieving the above object, the base plate 110 is formed in the form of a flat plate; A plurality of sub-modules 10 arranged to be spaced apart from each other on the upper surface of the base plate 110, each sub-module 10 includes a plurality of sub-modules 10 including a substrate and a plurality of solar cells formed on the substrate ); A conductive part 130 disposed in contact with each other or between the sub-modules 10; A cover plate 150 disposed on the upper surfaces of the sub modules 10; It may be made, including.

At this time, each of the sub-modules 10, including a CIGS absorbing layer, the non-uniformity of the Cu / (In + Ga) composition ratio of the material constituting the CIGS absorbing layer may be made in the range of 1% to 3%.

In addition, the nonuniformity in the longitudinal direction of each submodule 10 may be less than the nonuniformity in the width direction of each submodule 10.

In addition, the submodule 10 preferably has a length within the range of 1 cm to 30 cm.

In addition, the base plate 110 may be made of a metal material or a polymer material. Further, the substrate may be a soda lime substrate having a thickness in the range of 1 mm to 1.5 mm.

In addition, the substrate and the base plate 110 may be formed of different materials. Alternatively, the substrate and the base plate 110 may be formed of the same material, and the base plate 110 may be formed thicker than the substrate.

In addition, the sub module 10 may be formed in a square or rectangular shape.

In addition, the submodules 10 may have the same size.

In addition, the solar cell module 100 may have a direction extending from a plurality of scribing lines formed in the sub module 10 in a first direction and a direction perpendicular to the first direction on a plane of the base plate 110. In the second direction, the sub-modules 10 may be arranged in a plurality of rows in at least one direction selected from the first direction or the second direction. In this case, the solar cell module 100 may be disposed such that the conductive portion 130 is in contact with both ends of the second direction side of the sub module 10.

In addition, the sub module 10 may have a separation interval within the range of 0.1 to 10mm.

In addition, the solar cell module 100 includes an adhesive layer 120 for adhering the base plate 110 and the sub module 10 to each other; It may further include. In this case, the adhesive layer 120 may be a laminating film or an adhesive. In addition, the adhesive layer 120 may have a transmittance within a range of 80 to 100%.

According to the present invention, by manufacturing a large area module by combining sub-area sub-modules that can produce more high efficiency in manufacturing a large-area solar cell module, by removing the factor of efficiency deterioration due to nonuniformity in the conventional large area There is a great effect that makes it possible to manufacture large area solar cells.

In particular, according to the present invention, since a method of combining sub-modules having a small area is used, there is an effect that can be easily coped even if the area of the product to be produced varies in various ways. You can also get effects that make it easy. In addition, according to the present invention, since the solar cell module is completed by the electrical coupling of the sub-modules, even if the efficiency of the manufactured solar cell module is lower than expected, even if the defective product is found only to replace the sub-module in which the failure occurred This can be used as an intact product without destroying the entire product, which ultimately lowers the defective rate during quality control.

In addition, according to the present invention, since the sub-module itself has a small area, the production equipment can be miniaturized, and thus the equipment operability is improved, and accordingly, the productivity is also improved. In addition, as described above, according to the present invention, even if the panel size is increased, the replacement of equipment is not necessary, so that the cost for new equipment installation can be minimized even if the size of the product to be produced in the future becomes larger. There is also an economic effect.

1 is a structural schematic diagram of a monolithic integration solar cell module;

Figure 2 is an embodiment of a large area thin-film solar cell module manufacturing step of the present invention.

3 shows several embodiments of the solar cell module of the present invention.

4 is a cross-sectional view of one embodiment of a solar cell module of the present invention.

** Description of the sign **

1: substrate 2: electrode layer

3: absorber layer 4: permeable layer

5: cover plate

10: submodule

100: large area module 110: base plate

120: adhesive layer 130: conductive portion

140: sealing material 150: cover plate

Hereinafter, a thin film solar cell module using a sub module according to an embodiment of the present invention having the configuration as described above will be described in detail with reference to the accompanying drawings.

1 conceptually illustrates the structure of a monolithic integration solar cell module. As shown, a single integrated solar cell module includes a substrate 1, an electrode layer 2 formed on the substrate 1, an absorption layer 3 that absorbs light to generate electricity, and a transmission layer through which light passes ( 4) is made, including. In addition, a cover plate (superstrate) 5 may be further provided thereon to cover and protect the various layers as described above. As described above, in the case of the thin-film solar cell module, the substrate 1 is made of a material such as glass, and the absorption layer 3 / transmission layer 4 forms a P pole / an N pole, respectively, as shown in FIG. 1. As described above, the electrode layer 2, the absorbing layer 3, and the transmissive layer 4 may be stacked on the substrate 1, and a scribing line may be formed at an appropriate portion to implement a single integrated structure.

The present invention has been developed to solve the problem that the uniformity over a large area is not secured in the prior art in manufacturing a large area thin film solar cell capable of single integration as shown in FIG. To this end, the present invention employs a configuration in which a plurality of sub-modules, each of which is formed in the form of a solar cell as shown in FIG. 1 and which are relatively small (relative to the area of the large-area product to be completed), are arranged.

More specifically, it is as follows. Solar cell module 100 according to an embodiment of the present invention, the back plate (back plate, 110) formed in the form of a flat plate; A plurality of sub-modules 10 each arranged in a solar cell form and spaced apart from each other on an upper surface of the base plate 110; A conductive portion (bus-bar) 130 disposed in contact with or between the sub-modules 10; It comprises a; cover plate (superstrate, 150) disposed on the upper surface of the sub-module (10). In addition, the solar cell module 100 according to an embodiment of the present invention, between the base plate 110 and the submodule 10 or between the submodule 10 and the cover plate 150, an adhesive layer for stable fixing ( 120 may be further included, and may further include a sealing member 140 interposed between the base plate 110 and the cover plate 150 at the edge position of the base plate 110. Hereinafter, the connection configuration of each unit will be described by describing an embodiment of a large-area thin film solar cell module manufacturing step of the present invention with reference to FIG. 2.

First, the base plate 110 is disposed as shown in FIG. 2 (A). Next, as shown in FIG. 2C, a plurality of sub-modules 10 are arranged to be spaced apart from each other on an upper surface of the base plate 110, wherein the sub-modules 10 are arranged on the base plate 110. As shown in FIG. 2B, an adhesive layer 120 is formed on an upper surface of the base plate 110 between the base plate arranging step and the submodule arranging step so that the disposed form can be stably fixed. It is desirable to make more.

Next, as illustrated in FIG. 2D, the conductive parts 130 are disposed in contact with each other or between the submodules 10. Thereafter, as shown in FIG. 2F, the cover plate 150 is disposed on the upper surfaces of the sub-modules 10. Also, in this case, the cover plate 150 may be stably fixed in FIG. 2F. As shown in the drawing, the step of forming the adhesive layer 120 on the upper surface of the submodule 10 is preferably performed between the submodule arrangement step and the cover plate arrangement step. In addition, at this time, as shown in FIG. 2 (F), between the sub-module arrangement step and the cover plate arrangement step, so that contamination from the outside does not occur in the gap between the base plate 110 and the cover plate 150. For example, it is preferable that the step of providing the sealant 140 at the edge of the base plate 110 is made further.

Referring to each part of the solar cell module 100 according to an embodiment of the present invention in more detail. (The arrangement of the sub module 10 will be described in more detail later in the description of FIGS. 3 and 4, and thus description thereof is omitted here.)

The base plate 110 may be made of a material having an appropriate strength, that is, a metal material such as Al alloy or a polymer material such as polyimide, acrylic, etc. to maintain the shape of a large area plate well. At this time, the thickness of the base plate 10 is better so that the thickness of the final produced solar cell module 100 is not too thick, but if the base plate 10 is too thin, stably form a large area. It can be difficult to maintain. In consideration of this point, the base plate 10 preferably has a thickness within the range of 1 mm to 1.5 mm.

As described above, the adhesive layer 120 is provided between the base plate 110 and the sub module 10 or the sub module 10 and the cover layer 150 to ensure stable fixing, and a laminating film Or an adhesive. That is, the step of FIG. 2B or FIG. 2E may include a process of stacking films when the adhesive layer 120 is a laminating film, or apply an adhesive when the adhesive layer 120 is an adhesive. It may be done. At this time, when the light is blocked by the adhesive layer 120, the loss of the amount of light occurs, the battery efficiency is also reduced, the adhesive layer 120 has a property that can transmit the light as well as possible. That is, the adhesive layer 120 preferably has a transmittance within the range of 80 to 100%. As a specific material satisfying the above conditions, ethylene vinyl acetate (EVA), thermo plastic olefin (TPO), or kapton coated with an adhesive on a polyimide film may be used.

The cover plate 150 is provided to protect various components (particularly the sub modules 10) under the external shock or contamination. At this time, the cover plate 150, like the adhesive layer 120, in order to prevent the loss of the light amount caused by the cover plate 150, the cover plate 150 to have a transmittance within the range of 80 to 100% It is preferable. More specifically, the cover plate 150 may be made of a glass material.

In the solar cell module 100 according to an embodiment of the present invention, the size of the final product is to follow the area of the base plate (110). That is, as the area of the base plate 110 is increased, the large-area solar cell product can be manufactured. At this time, in the present invention, the plurality of sub-modules 10 are arranged on the base plate 110, as shown in Figure 2, the sub-modules 10 are electrically connected by the conductive portion 130 It takes a configuration that makes the whole module complete.

As described above, the area of the solar cell module to be manufactured due to the problem of non-uniformity is not uniformly implemented over the entire area in which the conditions that can achieve the optimum efficiency in manufacturing the solar cell module The wider the problem, the wider the efficiency. However, in the present invention, even if the area of the product to be produced is enlarged, a relatively small area of the plurality of sub-modules 10 are arranged on the base plate 110, thereby overcoming such nonuniformity problems. . In other words, when manufacturing a relatively small sub-module 10, the adverse effect of the non-uniformity problem is much less than the case of a large area, so that each sub-module 10 can obtain a high efficiency, such a high efficiency of the sub The modules 10 are electrically connected to form a large-area solar cell module 100, so that the efficiency of the large-area solar cell module 100 finally produced can be much improved than before.

More specifically, in the case of the co-evaporation method, in the large area (area> 0.5m ² ), the limitation of the deposition method, that is, the distribution of vaporized raw material sprayed onto the substrate in the form of a point is shown in the evaporation source. As the distance increases, it decreases, which causes a variation in thickness and composition, which can be very large, usually 5-10%. Meanwhile, the sub module 10 may be made of various materials, and for example, may include a CIGS absorber layer. In the case of the CIGS absorber layer, the composition ratio of Cu, ie, Cu / (In + Ga) ratio, is about to obtain the highest efficiency. that 0.85 ~ 0.95 is however known to be the optimum range, efficient distribution within this range would contain the absolute deviations of about 1-2% Thus, in normal substrate area of 1m ² class used for commercial production of satisfying the above composition range Even if the composition non-uniformity is a factor that lowers the output of the solar cell module (100). In addition, as the panel area increases, there is a problem in that the utilization (material utilization) of the supply amount of the raw material decreases rapidly to within <30%.

In order to solve this problem, in the present invention, the composition nonuniformity is limited to within 3%, and a small area having a length of one edge of the sub module 10 is 30 cm or less is used. (At this time, the smaller the length of one corner of the sub module 10, the higher the uniformity is, so the minimum value of the length of one corner is not important, but it is preferable that it is 1 cm or more in consideration of productivity, etc.) The composition and thickness nonuniformity is improved compared to the width of 60cm to 120cm, and the material utilization compared to the supply of raw materials can also be increased to> 60%, thus forming a raw material for forming an absorbing layer, which is about 30% of the manufacturing cost. It is possible to reduce the amount of use to about 1/2.

In the case of a large-area substrate, a thick substrate should be used to minimize bending of the substrate, and a general soda lime glass substrate has a problem of increasing the weight of the substrate by using about 3 mm, and is used to reduce the weight. In the case of high-distortion glass is about 1.8mm, there is a problem that the substrate cost is more than doubled. However, in the case of limiting to 30 cm or less as defined in the present invention, the thickness of the glass substrate can be used to 1.5 mm or less even when using soda lime, so that it is easy to handle during the process and can reduce the overall module weight. .

In addition, it is preferable to use a sub-module 10 of the same size for the module configuration through the arrangement of the sub-module 10. For integration of the sub-modules, another glass substrate may be used as a base material (ie, The base plate 110 may be made of glass, etc.), a curved roof, or a substrate made of a polymer material or a stainless steel foil so as to correspond to the exterior of a building, so that the entire module may have a curved shape. (Ie, the base plate 110 may be made of polymer, stainless steel foil, or the like).

3 shows various embodiments of the solar cell module of the present invention, and FIG. 4 shows a cross-sectional view of one embodiment of the solar cell module of the present invention. The detailed configuration of the solar cell module 100 according to the embodiment of the present invention will be described in more detail with reference to FIGS. 3, 4 and the foregoing drawings.

As shown in FIG. 3, the sub module 10 may be formed in a square or rectangular shape so as to easily arrange the columns on the base plate 110. Of course, even if the sub-module 10 has a different shape, it is also possible to design a layout form that can obtain a good efficiency, but considering the manufacturing method of a general thin-film solar cell, since the square or rectangular shape is most easy to manufacture Considering not only ease of arrangement but also ease of manufacture, it is most preferable that the submodule 10 has a square or rectangular shape as shown in FIG. 3.

In particular, the sub module 10 may have the form of a monolithic integrated solar cell. That is, the sub module 10 may be in the form of a solar cell unit, or may be in the form of a single integrated solar cell in which a scribing line is formed as illustrated in FIG. 1 or 4. If the area of the submodule 10 is too small, the difficulty of arranging the submodule 10 may be increased, and thus productivity may worsen. Therefore, the submodule 10 also has an appropriate area at a level where the effect of deterioration is not high. If the area of the submodule 10 is formed to be wider than the general unit cell level, the submodule 10 may be a single integrated solar cell (with a scribe line formed therein). It is desirable to be in the form.

At this time, as shown in FIG. 3, the extending direction of the plurality of scribing lines formed in the sub-module 10 is determined in a first direction and a direction perpendicular to the first direction on the base plate 110 plane. When referred to as the second direction, the sub-module 10 is arranged in a plurality of rows arranged in at least one direction selected from the first direction or the second direction. FIG. 3 (A) shows the form in which the sub-modules 10 are arranged in a plurality of rows in both the first direction and the second direction, and FIG. 3 (B) shows the plurality of rows of the sub-modules 10 in the first direction only. 3 (C) shows a form in which the sub-modules 10 are arranged in a plurality of rows only in the second direction.

When determining this type of arrangement, the configuration of the production equipment can be taken into account. For example, if a sub-module is manufactured using an in-line deposition equipment, since the equipment has excellent uniformity according to the direction in which the substrate is transported in the equipment, a narrow and long form (ie The configuration of the sub module shown in FIG. 3 (C) is easy. In this way, the shape of the submodule 10 may be appropriately determined as a shape capable of ensuring sufficient uniformity in the production of the submodule 10 in consideration of the configuration form of the production equipment.

In order for the solar cell module 100 to operate, the sub modules 10 should not only be arranged, but the sub modules 10 should be electrically connected. To this end, the conductive part 130 which electrically connects the sub modules 10 is disposed to be in contact with both ends of the second direction side of the sub module 10 as shown. By arranging the conductive portions 130 as described above, the sub-modules 10 arranged in the second direction, that is, the direction perpendicular to the scribing line are connected in series with each other, and are parallel to the first direction, that is, the scribing line. The sub modules 10 arranged in the direction are connected in parallel with each other. Therefore, the final output voltage of the solar cell module 100 may be obtained by multiplying the voltage of one submodule 10 by the number of columns of the submodule 10 in the second direction, and the final output current is one submodule ( It can be obtained by multiplying the current generated in 10) by the number of columns of the sub module 10 in the first direction.

At this time, as described above, the voltage and current values generated in one submodule 10 are known, and the solar cell module 100 of the large-area solar cell module 100 that is finally manufactured by using the number of arrangement columns of the submodule 10 is known. The output voltage and current values can be expected. When the production finished product inspection is lower than the expected value, in the case of the present invention does not have to destroy the entire product, it is only necessary to find the sub-module 10 in which the defect occurred and replace it. Therefore, the configuration of the present invention, not only improves the efficiency of the product itself, but also can lower the defective rate in quality control as well as its repair is very easy and economical has a great advantage.

The present invention is not limited to the above-described embodiments, and the scope of application of the present invention is not limited to those of ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Of course, various modifications can be made.

According to the present invention, in manufacturing a large area solar cell module, there is a great effect of making a large-area solar cell of high efficiency by eliminating the factor of efficiency deterioration caused by nonuniformity in the conventional large area. In addition, even if the area of the product to be produced is varied, there is an effect that can be easily responded, and by this effect can also be obtained to facilitate the production of products of the desired standard. Ultimately, quality control is also effective in reducing defect rates. In addition, according to the present invention, the production equipment can be miniaturized to improve the equipment operability, of course, there is an effect that the productivity is also improved.

Claims

A base plate formed in a flat plate shape;

A plurality of sub-modules arranged to be spaced apart from each other on the base plate, wherein each sub-module includes a plurality of sub-modules including a substrate and a plurality of solar cells formed on the substrate;

Conductive parts disposed in contact with each other or between the sub-modules;

A cover plate disposed on an upper surface of the sub modules;

Solar cell module comprising a.
The method of claim 1, wherein each sub-module

A solar cell module comprising a CIGS absorber layer, wherein the nonuniformity of the composition ratio of Cu / (In + Ga), which is a material constituting the CIGS absorber layer, is in a range of 1% to 3%.
The method of claim 2,

The nonuniformity in the longitudinal direction of each submodule is less than the nonuniformity in the width direction of each submodule.
The method of claim 1, wherein the sub module is

A solar cell module having a length in the range of 1 cm to 30 cm.
The method of claim 1, wherein the base plate

Solar module made of metal or polymer material.
The method of claim 1, wherein the substrate

A solar cell module which is a soda lime substrate having a thickness in the range of 1 mm to 1.5 mm.
The method of claim 1, wherein the substrate and the base plate

Solar cell module formed of different materials from each other.
The method of claim 1, wherein the substrate and the base plate

The solar cell module is formed of the same material as each other, the base plate is thicker than the substrate.
The method of claim 1, wherein the sub module is

Solar module consisting of square or rectangular shape.
The method of claim 1, wherein the sub module is

Solar module made of the same size with each other.
The method of claim 1, wherein the solar cell module

When the direction of extension of the plurality of scribing lines formed in the sub module is a first direction and the direction perpendicular to the first direction on the base plate plane is called a second direction,

The sub module is arranged in a row arranged in a plurality of rows in at least one direction selected from the first direction or the second direction.
The method of claim 11, wherein the solar cell module

The solar cell module is disposed such that the conductive portion is in contact with both ends of the second direction side of the sub-module.
The method of claim 1, wherein the sub module is

Solar cell module having a spacing interval within the range of 0.1 to 10mm.
The method of claim 1, wherein the solar cell module

An adhesive layer for bonding the base plate and the sub module together;

Solar module further comprising.
The method of claim 14, wherein the adhesive layer

Solar cell module which is a laminating film or adhesive.
The method of claim 14, wherein the adhesive layer

Solar cell module having a transmittance in the range of 80 to 100%.