KR20190136687A - Protective film for Solar Cell and preparation method thereof - Google Patents

Abstract

A protective film for photovoltaic cell of the present invention is detachable and separable. When a surface of a photovoltaic cell is contaminated or damaged, the surface of the photovoltaic cell may always maintain an optimal state by only replacing the protective film without replacing the entire photovoltaic cell like an existing method, and the reflection of light is suppressed at the same time, thereby increasing amount of incident light and significantly increasing the energy conversion efficiency of the photovoltaic cell. In addition, since a pattern effect widely used for anti-reflection film is not necessary, the protective film for photovoltaic cell has many advantages in terms of costs and maintenance.

Description

Protective film for solar cell and preparation method thereof

The present invention relates to a protective film for solar cells, more specifically, a layer of a constant thickness is provided in a multi-layered, protective film of the detachable form of detachable, not integral, attached to the solar cell, to protect from the external environment and At the same time, the present invention relates to a protective film and a method for manufacturing the same, which can significantly increase energy conversion efficiency even though a pattern commonly used as an antireflection is omitted.

Recently, environmental issues have emerged as social issues. As alternative energy to solve this problem, hydro power generation, wind power generation and solar power generation have been pointed out. Among them, solar power generation using solar energy is attracting attention as the most clean and useful energy source, and various research and development has been made. Representatively, there is a solar cell, which is a technology that converts sunlight absorbed by a solar cell that absorbs sunlight into electrical energy using the properties of a semiconductor. In general, solar cell modules can be classified into silicon solar cells, thin film solar cells, dye-sensitized solar cells and organic polymer solar cells according to the material constituting the solar absorption cell, crystalline silicon (Bulk type) to date Solar cell module using the most is the mainstream. However, there is a problem in that the crystalline silicon wafer substrate and the high-purity polysilicon, which is a raw material of the substrate, have a short supply compared to demand, resulting in high manufacturing costs and high power consumption during manufacturing. In order to solve the high manufacturing cost of the crystalline silicon solar cell module, solar cells using various types of solar absorption cells such as silicon thin film solar cells, compound solar cells, and dye-sensitized solar cells have been continuously developed.

Despite the various structural improvements described above, when the solar cell is substantially applied, the conventional solar cell is very vulnerable to moisture or oxygen existing in the external environment, and is easily damaged, and the surface is soot because the panel is always exposed. Easily soiled by numerous pollutants such as dirt, dust and sand. If the solar cell is seriously polluted by the external environment, the panel is cleaned. In this process, damage occurs and the cleaning often does not return to its original state. Due to such many causes, the photovoltaic power generation efficiency is easily lowered even if it is commercialized, and thus does not exhibit sufficient efficiency. Particularly, since solar cells are sensitive to the inflow of light, if any point is contaminated by the pollutant, the power generation efficiency is reduced by up to 20-30% in overall efficiency, and a thin anti-reflective surface is invisible on the surface of the panel. In case of coating, professional equipment or skill is required for cleaning process.

In addition, if the solar cell does not return to its original state due to various causes such as damage or damage or external pollutants due to the above-mentioned causes, the solar cell must be replaced not only on the part or the surface of the solar cell, but also on the entire solar cell. In addition, there is a difficulty in maintenance and maintenance, and if damaged or contaminated, there is a problem that a serious economic loss occurs.

Patent Document 1. Republic of Korea Patent Publication No. 10-1989-702258

The present invention has been made in view of the above problems, the object of the present invention is to protect the solar cells, such as solar cells from the external environment, easy to remove and replace easily when contamination, as well as to prevent reflection of light It is to provide a protective film to increase the efficiency of the solar cell by increasing the amount of incident light.

It is another object of the present invention to provide a method for manufacturing the protective film, in which a conventional pattern forming step, which is difficult in mass production, is omitted.

The present invention, in order to achieve the above object, the base portion having an adhesive force; And a surface layer portion laminated on one surface of the base layer portion and including at least one layer having a thickness of 0.1 to 1.5 mm.

The base portion is polydimethylsiloxane (PDMS), polycarbonate (PC), polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), It may be any one selected from the group consisting of ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP).

The surface portion is polydimethylsiloxane (PDMS), polycarbonate (PC), polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), It may be any one selected from the group consisting of ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP).

The surface layer portion may be provided with a number of layers selected from 1 to 20 layers.

Each layer of the surface layer portion may have the same thickness.

The protective film for solar cells may have a 35 to 40% reflectivity of light of 350 to 400 nm wavelength.

The present invention provides a method for manufacturing a protective film for solar cells comprising the following steps to achieve the above object.

I) coating and curing the composition for preparing a protective film to prepare a base portion; And

Ⅱ) coating a composition for preparing a protective film on one side of the base portion and curing to prepare a layer having a thickness of 0.1 to 1.5 mm, by repeating this process to form a surface layer consisting of at least one layer.

Alternatively, a) applying a composition for preparing a protective film, curing to prepare a film of a constant thickness, and attaching the film to one side of the layer layer to prepare a solar cell protective film consisting of a surface layer portion having a base portion and at least one layer. It may include.

The protective film production composition includes a polysiloxane polymer, a curing agent, a silane coupling agent and an organic solvent, and based on 100 parts by weight of the polysiloxane polymer, 1 to 20 parts by weight of a siloxane curing agent; 0.005 to 5 parts by weight of a silane coupling agent selected from the alkoxy silane compounds.

The curing may be performed for 90 to 100 ℃, 0.5 to 2 hours.

The protective film for solar cells of the present invention is detachable and detachable, and when the surface of the solar cell is contaminated or damaged, there is no need to replace the entire solar cell as in the conventional method, and by replacing only the protective film, the state of the solar cell surface is always best In addition, it is possible to maintain the light source, and at the same time, suppress the reflection of light and thereby increase the amount of incident light, thereby significantly increasing the energy conversion efficiency of the solar cell. In addition, there are many advantages in terms of cost and maintenance because the pattern effect itself, which is widely used for an anti-reflection film, is not required.

1 is a perspective view showing the structure of a protective film for solar cells of the present invention.
Figure 2 shows the state when the protective film of the present invention attached to the solar cell.
3 is a cross-sectional view showing a structure when the protective film prepared in Examples 1 to 10 is attached to a surface of a solar cell (GaAs or Si bulk solar cell). (a) is to attach the protective film prepared from Example 1, (b) is to attach the protective film prepared from Example 2, (c) is to attach the protective film prepared from Example 4 (d) attaches the protective film prepared in Example 5, and (e) attaches the protective film prepared in Example 8.
Figure 4 is a cross-sectional view showing the structure when the protective film prepared from Comparative Examples 1 to 6 attached to the surface of the solar cell (GaAs or Si bulk solar cell). (a) is to attach a protective film prepared from Comparative Example 1, (b) is to attach a protective film prepared from Comparative Example 2, (c) is to attach a protective film prepared from Comparative Example 3 , (d) is to attach a protective film prepared from Comparative Example 4, (e) is to attach a protective film prepared from Comparative Example 5, (f) is to attach a protective film prepared from Comparative Example 6 will be.
5 is a photograph (a) showing the structure of the GaAs solar cell is not attached to the protective film in Experimental Example 1 and a photograph (b) taken a state in which the protective film prepared in Example 2 is attached to the GaAs solar cell. .
6 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 on the upper surface of the GaAs solar cell.
7 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective films prepared from Comparative Examples 2, 3 and 4 on the upper surface of the GaAs solar cells.
FIG. 8 is a photograph of a si solar cell (monocrystalline) having no protective film attached in Experimental Example 2 and a photograph of a state in which the protective film prepared in Example 10 is attached on a si solar cell (monocrystalline). It is photograph (b).
9 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared in Examples 4 to 10 on the upper surface of the si solar cell (monocrystaliine).
10 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Examples 4, 5, 8 and Comparative Examples 4 to 6 on the upper surface of the si solar cell (monocrystaliine).
FIG. 11 is a photograph of a solar cell si module (module) not having a protective film attached to Experimental Example 3 (a) and a state in which the protective film prepared from Example 5 is attached to a solar cell si module (module); It is a photograph (b) taken.
12 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 on the solar cell si module (module) upper surface.
13 is a graph showing the solar cell reflectivity (reflectance%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 10 on the GaAs solar cell upper surface.
14 is a cross-sectional view showing a structure when the protective film prepared from Comparative Examples 7 to 12 is attached to the surface of a solar cell (GaAs solar cell). (a) is to attach a protective film prepared from Comparative Example 7, (b) is to attach a protective film prepared from Comparative Example 8, (c) is to attach a protective film prepared from Comparative Example 9. , (d) is to attach a protective film prepared from Comparative Example 10, (e) is to attach a protective film prepared from Comparative Example 11, (f) is to attach a protective film prepared from Comparative Example 12 will be.
15 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 and Comparative Examples 7 to 12 on the upper surface of the GaAs solar cell.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

In the case of the protective film in which at least one layer having a constant thickness of a flat shape is formed as in the present invention, when the thicknesses of the layers are different from each other, or when the pattern layer is inserted, the efficiency of the solar cell is reduced. The degree of increase is not large, and the force acting on the interface is changed, so that the case of detachment occurs during detachment, and the effect of preventing reflection and increasing light absorption is insignificant. In addition, when the layers of different materials are introduced, a phenomenon in which the protective film is peeled from a solar cell such as a solar cell may occur due to a swelling phenomenon caused by an organic compound during long-term use.

Therefore, the present invention uses a polysilonic acid-based polymer, to produce a protective film having a structure in which at least one layer of the same thickness is repeatedly laminated with the same material, effectively blocking the solar cells such as solar cells from the harmful environment and At the same time, the efficiency of the solar cell is improved by increasing the amount of incident light due to the surface reflection prevention of light.

According to an aspect of the invention, the base portion having an adhesive force; And a surface layer portion stacked on one surface of the base layer portion and including at least one layer having a thickness of 0.1 to 1.5 nm. Its structure is shown in detail in FIG. 1 is a perspective view showing the structure of a protective film for solar cells of the present invention.

Referring to FIG. 1, the protective film 100 for solar cells of the present invention includes at least one layer 121, 122, 123 ... having a thickness of 0.1 to 1.5 nm on one surface of the substrate 110. Surface layer portion 120 is provided. In this case, in the surface layer portion 120 including the at least one layer, each layer 121, 122, 123..., In a flat shape, does not include a pattern.

The base layer 110 and the surface layer 120 may have a selected mechanical property such as Young's modulus or flexural rigidity, or a selected thermal property such as a thermal expansion coefficient, or may use different polymers. For example, the same polymer material having different modulus may be used. Preferably, the base layer portion 110 and the surface layer portion 120 are effective to prevent problems such as separating and detaching from each other when the same polymer material is used.

In addition, the substrate 110 may be provided on the other surface of the surface layer 120 to provide a property that can be attached to a solar cell or various devices.

The base portion 110 is polydimethylsiloxane (PDMS), polycarbonate (PC), polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP) can be any one selected from the group, the surface layer portion 120 is polydimethylsiloxane (PDMS), polycarbonate (PC) , Polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP It can be any one selected from the group consisting of, as described above to use the same polymer material with each other to prevent problems such as detached and detached from each other when detached good.

More preferably, among the polymers that can be used as the base layer 110 and the surface layer 120, the polydimethylsiloxane having the most adhesive property and the most transparency may be used.

In general, polydimethylsiloxane has a low modulus (3 MPa) and has a high compressibility (2.0 N / mm 2), so that problems related to deformation due to pressure are easily generated. There is a problem that the solar cell can not be sufficiently protected from the external environment, and the effect of increasing the energy conversion efficiency of the solar cell was also insignificant.

In addition, even when the pattern layer is formed, the process of forming the pattern is not only complicated and expensive, but the size, spacing, and the like of the protrusions forming the pattern greatly affect the reflection of the incident light. If there is any distortion (buckling, sagging of the side walls), a problem occurs that causes a decrease in the light transmittance. Therefore, when this is used as a protective film, since the deformation of the pattern is easily caused by the external environment, the replacement cycle of the protective film is fast, and the effect of reducing the cost in terms of maintenance is insignificant. As described above, there is a problem that the effect of increasing the energy conversion efficiency of the solar cell is relatively low. Therefore, it is not easy to manufacture a patterned film with a protective film.

The surface layer portion 120 may be provided with the number of layers selected from 1 to 20 layers, each layer of the surface layer portion preferably has the same thickness.

As described above, the protective film according to the present invention has an effect of improving the efficiency of the solar cell by 1% to 5% even without having inorganic particles or a pattern layer. That is, the protective film of the present invention increases the effect of gradually improving the efficiency of the solar cell as the layers of the same material of the same thickness is repeatedly stacked, by adhering to the front of the solar cell irrespective of the thickness, the solar cell outside It is possible to further increase its efficiency while protecting from the environment.

The structure of the surface layer portion 120 is a flat (flat) structure, the surface reflectance is gradually lowered by forming a layer of such a constant thickness in the number of layers selected from 1 to 20 layers, does not produce a strong scattered light Structure was achieved. The protective film according to the present invention has advantages such as the surface reflection can be further reduced through a simple structural design without having a pattern layer manufactured through a complicated manufacturing process.

That is, the surface layer 120 is most preferable because it is a structure in which a flat film-like layer is repeatedly laminated, since the surface reflection can be further reduced.

Each layer of the surface layer portion 120 may have a thickness of 0.1 to 1.5 mm, the thickness of each layer is less than 0.1 mm, more than 1.5 mm, or any one of the layers constituting the surface layer portion is thick If it is out of 0.1 to 1.5 mm, when attached to one side of the conventional solar cell, there is a disadvantage that the effect of increasing the efficiency of the solar cell is lowered to less than 2%. In addition, if less than 0.1 mm, it is difficult to manufacture, additional time and cost is required, and it becomes difficult to provide a protective film at low cost because it becomes sensitive to produce a layer of uniform thickness. Most preferably, each layer of the surface layer portion 12 may have a thickness of 0.8 to 1.3 mm. Because the reflectivity reflecting light is significantly different depending on the thickness of the layer, when each layer constituting the surface layer portion has a thickness in the above range, even if a plurality of layers are stacked together, the anti-reflection effect of the light cancels or interferes with each other. This is because the light incident rate is superimposed and overlapped, and thus the light incident rate is increased, and thus the solar cell energy conversion efficiency can be remarkably increased.

In this case, the base layer 110 preferably has the same material and the same thickness as that of the surface layer 120. If the base layer 110 has a different thickness, when the protective film 100 is attached on the solar cell, the solar cell The problem arises that the effect of increasing the energy conversion efficiency of is insignificant.

The surface layer portion 120 of the protective film 100 for solar cells according to the present invention is preferably formed by sequentially stacking layers 121, 122, 123 ... having a thickness of 0.1 to 1.5 mm, the layer ( 121, 122, 123 ...) are most preferably of constant thickness. Herein, the term “constant” specifically refers to a state in which the thicknesses of the layers 121, 122, 123... Are uniformly stacked to any thickness selected from 0.1 to 1.5 mm, for example, the surface layer part 120. When the thickness of one of the layers 121) is 1 mm, the thicknesses of the other layers 122, 123... Forming the surface layer part 120 are also uniformly formed at 1 mm. In other words, the thicknesses of the layers 121, 122, 123...

If the thicknesses of the layers 121, 122, 123... Of the surface layer portion 120 are different from each other or deviate from any one layer having a thickness of 0.1 to 1.5 mm, the protective film 100 may be attached to the solar cell. At this time, the effect of increasing the amount of incident light due to the reflection of light is reduced, so that the energy conversion efficiency of the solar cell also decreases.

In addition, the film for solar cells having the above-described characteristics of the present invention is more excellent when compared to the pattern film generally used as anti-reflection (AR) film. Not only is the effect of increasing the efficiency of the solar cell outstanding, but also the complicated process of forming a pattern can be omitted, thereby reducing the costs incurred in the process and maintenance.

In the solar cell protective film 100 according to the present invention, the surface layer portion 120 including at least one layer having a thickness of 0.1 to 1.5 nm is stacked on one surface of the base layer portion 110 having an adhesive force. 120), despite the fact that a plurality of flat layers which do not contain a pattern are stacked, not only protects solar cells such as solar cells from the external environment but also significantly improves efficiency by 1 to 5% or more. It can be seen that. In general, in the solar cell field, it can be said that it is possible to increase the efficiency even by 0.1% by adding one or more structures to the solar cell having an optimized structure. Accordingly, the protective film of the present invention not only increases the efficiency of 1% to 5%, which is 10 to 50 times thereof, and is easily removable, so that when a solar cell such as a solar cell is damaged or damaged or the surface is contaminated, the entire solar cell It is very useful in terms of cost and environmental pollution problem in maintenance because only the protective film can be replaced without a need to remove it.

In addition, the protective film for the solar cell has a reflectance of 35 to 40% of the light of 350 to 400 nm wavelength, which is significantly lower than the reflectivity of the reference substrate is not applied 50 to 55% of the protective film. That is, the protective film for solar cells can be seen to reduce the reflection of light, increase the amount of incident light to increase the solar cell efficiency.

The protective film for solar cells according to the present invention achieves the above-described effects without additional structures such as inorganic particles or quantum dots therein, and since there is no additional structure inside, the transparency is very excellent, and the light transmittance is visible in the visible region 400 ~. 700 nm) has an advantage of reaching 90%.

This is due to the simple but limited structure of the base portion 110 and the surface layer portion 120 of the protective film 100 according to the present invention as described above, while reducing the reflection of light while protecting the solar cell from the external environment, It can be seen that the solar cell efficiency increased by 1-5% by increasing the incident light amount.

Since the protective film 100 according to the present invention has an adhesive property, the protective film 100 does not need to be sintered or complicated manufacturing process by using the protective film 100 on various devices, including solar cells, on the surface of solar cells and various devices. Desorption is easy. Therefore, the process of adhering the protective film, there is an advantage that a problem such as deformation or cracking of the solar cell or solar cell does not occur.

In addition, the protective film 100 according to the present invention can be easily provided to the various devices through a simple operation of attaching to a variety of devices, including solar cells using the adhesive, through the process is provided with the protective film 100 In addition to increasing the amount of incident light, the various devices have a very high light transmittance, thereby increasing energy conversion efficiency.

In other words, even solar cells having various structures developed to date (for example, CIGS or solar cells provided with a general anti-reflection film), when the protective film 100 of the present invention is attached to its surface, various sources of pollution present in the external environment In addition to being protected from external forces, the efficiency can be improved by 1-5% or more.

In addition, another aspect of the present invention relates to a method for manufacturing the protective film for solar cells comprising the following steps.

I) coating and curing the composition for preparing a protective film to prepare a base portion; And

Ⅱ) by applying the composition for the protective film production on one surface of the base portion and curing to prepare a layer having a thickness of 0.1 to 1.5 mm, repeating this process to form a surface layer consisting of at least one layer.

The manufacturing method of the protective film for solar cells according to the present invention is not particularly limited to a manufacturing method generally used in the art, more specifically, may be prepared by the following method.

First, a composition for preparing a protective film in which a polysiloxane polymer, a curing agent, and a silane coupling agent are mixed with an organic solvent is prepared. The organic solvent is generally used in the art and is not particularly limited. For example, any one or more selected from hexane, cyclohexane, dichloromethane, dichloromethane, dichloroethane, pentane and heptane may be used.

Specifically, the composition for preparing the protective film may include 1 to 20 parts by weight of the curing agent and 0.005 to 5 parts by weight of the silane coupling agent based on 100 parts by weight of the polysiloxane polymer. When the content of the silane coupling agent is too small, there is a lack of compatibility between the inorganic particles and the polysiloxane-based polymer, poor binding strength of the support, and may cause a problem that the hybrid composite membrane is peeled off on the porous polymer and the inorganic support. When the amount exceeds 5 parts by weight, the silane coupling agent may increase the free volume of the polysiloxane-based polymer, thereby reducing the separation selectivity of the volatile organic compound. Therefore, it is preferable to use the silane coupling agent in the above content range.

The silane coupling agent is preferably an alkoxy group silane compound, more preferably vinyl group, glycidyl group, styryl group, methacryl group, acrylic group, ureido group, chloroalkyl group, mercapto group, isocyanate group, It is preferable to use an alkoxy silane compound further substituted with a functional group selected from an amino group, a dimethylamino group, an imidazole group and an acetoacetate group. More specifically, the silane coupling agent (d) has a hydrophobic organic functional group, most preferably γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxy Propyltriethoxysilane, 3-mercapto propyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, 3-aminopropylmethoxydiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, and γ-acetoacetatepropyltrimethoxysilane It is good.

In addition, the curing agent is a siloxane-based curing agent, it is preferable to use in the range of 1 to 20 parts by weight based on 100 parts by weight of the polysiloxane-based polymer. Specifically, the siloxane-based curing agent may be methyl siloxane, dimethyl hydrosiloxane, and the like, and the present invention does not specifically limit the kind of these siloxane-based curing agents.

Applying the composition for preparing the protective film prepared above and curing to prepare a base portion. Specifically, the coated protective film preparing composition performs a crosslinking reaction by evaporating a solvent. The crosslinking reaction may be slowly evaporated at room temperature or may be performed at 90 to 100 ° C. for 0.5 to 2 hours. Since it is preferable to completely volatilize, it is best to carry out at 90-100 degreeC for 0.5 to 2 hours.

Next, the protective film manufacturing composition is applied to one surface of the base portion and cured to produce a layer having a thickness of 0.1 to 1.5 mm, and the process is repeated to form a surface layer portion composed of at least one layer.

The prepared protective film manufacturing composition is applied to one surface of the base layer portion and cured to prepare a layer 121 located at the bottom of the surface layer portion. Next, after the layer 121 is sufficiently cured, the surface of the at least one layer may be formed by repeating the process of applying and curing the composition for preparing the protective film.

The surface layer is also applied through the crosslinking reaction by applying the composition for preparing the protective film, the solvent is evaporated, the crosslinking reaction may be carried out to evaporate the solvent slowly at room temperature, or 0.5 to 2 hours at 90 to 100 ℃ Although it is preferable to completely volatilize the solvent, it is best to carry out at 90 to 100 ℃ for 0.5 to 2 hours.

In addition, another aspect of the present invention relates to a method of manufacturing a protective film for a solar cell comprising the following steps.

a) applying a composition for preparing a protective film, and curing to prepare a film having a constant thickness, and attaching the film to one side of the film to prepare a protective film for solar cells comprising a base layer portion and a surface layer portion having at least one layer. can do.

The manufacturing method of the protective film for solar cells according to the present invention is not particularly limited to a manufacturing method generally used in the art, more specifically, may be prepared by the following method.

First, a composition for preparing a protective film in which a polysiloxane polymer, a curing agent, and a silane coupling agent are mixed with an organic solvent is prepared. The organic solvent is generally used in the art and is not particularly limited. For example, any one or more selected from hexane, cyclohexane, dichloromethane, dichloromethane, dichloroethane, pentane and heptane may be used.

Specifically, the composition for preparing the protective film may include 1 to 20 parts by weight of the curing agent and 0.005 to 5 parts by weight of the silane coupling agent based on 100 parts by weight of the polysiloxane polymer. When the content of the silane coupling agent is too small, there is a lack of compatibility between the inorganic particles and the polysiloxane-based polymer, poor binding strength of the support, and may cause a problem that the hybrid composite membrane is peeled off on the porous polymer and the inorganic support. When the amount exceeds 5 parts by weight, the silane coupling agent may increase the free volume of the polysiloxane-based polymer, thereby reducing the separation selectivity of the volatile organic compound. Therefore, it is preferable to use the silane coupling agent in the above content range.

The silane coupling agent is preferably an alkoxy group silane compound, more preferably vinyl group, glycidyl group, styryl group, methacryl group, acrylic group, ureido group, chloroalkyl group, mercapto group, isocyanate group, It is preferable to use an alkoxy silane compound further substituted with a functional group selected from an amino group, a dimethylamino group, an imidazole group and an acetoacetate group. More specifically, the silane coupling agent (d) has a hydrophobic organic functional group, most preferably γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxy Propyltriethoxysilane, 3-mercapto propyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, 3-aminopropylmethoxydiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, and γ-acetoacetatepropyltrimethoxysilane It is good.

In addition, the curing agent is a siloxane-based curing agent, it is preferable to use in the range of 1 to 20 parts by weight based on 100 parts by weight of the polysiloxane-based polymer. Specifically, the siloxane-based curing agent may be methyl siloxane, dimethyl hydrosiloxane, and the like, and the present invention does not specifically limit the kind of these siloxane-based curing agents.

a) The composition for protective film manufacture was apply | coated and hardened | cured, and the film of constant thickness was produced. Thereafter, one of the prepared films was a base layer portion, and another film previously prepared was attached to the upper surface of the base layer portion to prepare a single layer surface layer portion. That is, a plurality of films having a predetermined thickness are prepared in advance, and then layered on one surface of the base layer portion to form a surface layer portion formed of at least one or more layers having a thickness of 0.1 to 1.5 mm.

The composition for preparing the protective film is applied and the solvent is evaporated to perform a crosslinking reaction. The crosslinking reaction may be slowly evaporated at room temperature or may be performed at 90 to 100 ° C. for 0.5 to 2 hours, and the solvent may be completely removed. Since it is preferable to volatilize, it is best to carry out for 0.5 to 2 hours at 90-100 degreeC.

In addition, another aspect of the present invention is a solar cell (200); And it relates to a solar cell comprising the protective film 100 attached to the solar incident surface or the upper surface of the solar cell 200.

In this case, the protective film 100 may be formed by simply bonding and adhering the solar light incident surface or the upper surface of the solar cell 200.

The solar cell 200 generates current by absorbing incident light to generate holes and electrons, and is not particularly limited as long as it is a solar cell used in the art, for example, an element semiconductor, a compound semiconductor, and an organic It is based on a semiconductor and the like, and may have various structures. In addition, the solar cell 200 may be a silicon-based, copper indium gallium selenium (CIGS) -based or copper zinc tin sulfur (CZTS) -based or gallium arsenide (GaAs) -based solar cell 200.

An example of the structure of the solar cell 200 to which the protective film is attached is shown in FIG. 2.

Referring to this, the solar cell 200 includes a substrate 210, a first semiconductor layer 230, a light absorption layer 240, and a second semiconductor layer 250, and the sunlight of the solar cell 200. The protective film 100 may be formed to cover the incident surface or the upper surface.

In this case, the upper surface refers to an upper surface of the uppermost layer forming the solar cell 200. In the embodiment of the present invention, the protective film 100 may be formed on the second semiconductor layer 250.

The substrate 210 is not particularly limited as long as it is a conventional material used as a substrate in the art, and specifically, may be any one selected from the group consisting of glassy, metal, ceramic, and polymers. The substrate 210 may be a GaAs or Ge substrate. In the exemplary embodiment of the present invention, the substrate 210 is made of GaAs. When GaAs is used, the substrate 210 is formed as the first semiconductor layer 230 and the absorption layer 240. A quantum dot layer can be laminated.

The thickness and area of the substrate 210 are not particularly limited, and an appropriate dimension may be selected in consideration of the characteristics of the substrate material and the semiconductor compound used.

The buffer layer 320 made of the same material as the substrate may be formed on the substrate 210. This may be omitted or added according to the use of the solar cell 200. 2 is a perspective view showing the structure of a solar cell 200 according to the present invention without the buffer layer 220 (not shown).

The solar cell 200 may further include a lower electrode layer 211 on the rear surface of the substrate 210, and further include an upper electrode layer 251 on the second semiconductor layer 250 (not shown). ), ZnO, Ni, Al, Ti, Ag, Au, Co, Sb, Pd, Cu, TiN, WN, etc. may be used alone or in combination as the lower electrode layer 211 and the upper electrode layer 251. In some cases, these may be laminated films. The lower electrode layer 211 and the upper electrode layer 251 may be made of the same material or different materials. In some cases, a transparent conductive material, for example, a transparent conductive oxide (TCO), may be used. The TCO material may be indium tin oxide, indium zinc oxide, or gallium oxide. Zinc (gallium zinc oxide), aluminum zinc oxide (aluminum zinc oxide) or a combination thereof can be exemplified.

The lower electrode layer 211 and the upper electrode layer 251 may be formed by low pressure chemical vapor deposition (LPCVD), PECVD, atomic layer deposition (ALD), sputtering, electron-beam evaporation, and the like. However, the present invention is not necessarily limited thereto.

The first semiconductor layer 230 is formed on the buffer layer 220 or the substrate 210 and may mean an "n-type semiconductor layer" or a "p-type semiconductor layer", and typically It has the opposite conductivity characteristic, so that the incident light is absorbed by the light absorbing layer in the solar cell structure to form a junction structure that can cause a photoelectric effect. For example, the p-type semiconductor may be doped with a group II component to a group III-V compound semiconductor, and the n-type semiconductor may be doped with a group IV component to a group III-V compound semiconductor. At this time, the impurity ion concentration ranges in the p-type and n-type semiconductors are not particularly limited.

The light absorbing layer 240 is formed on the first semiconductor layer 230. The light absorbing layer 240 generates sunlight by generating an electron-hole pair by receiving sunlight, and includes one or more quantum dot layers having different energy band gaps. do.

In addition, the light absorption layer 240 may include one or more III-V compound semiconductor layers (hereinafter, referred to as compound semiconductor layers) having different energy band gaps. Each layer of the light absorbing layer 240 has a different band gap and may be formed to absorb sunlight having different wavelengths, but the order or number of layers is not necessarily limited.

The light absorption layer 240 may include one or more compound semiconductor layers and one or more quantum dot layers. In this case, the light absorption layer 240 may include one or more quantum dot layers on one or more compound semiconductor layers, or one or more quantum dots. One or more compound semiconductor layers may be included on the layer.

In addition, the quantum dot layer may be formed between the compound semiconductor layer, and the compound semiconductor layer may be formed between the quantum dot layer.

The light absorption layer 240 may be formed in a tandem manner by the two or more quantum dot layers.

The light absorbing layer 240 may be formed by stacking the compound semiconductor layer and the quantum dot layer in multiple layers. In this case, the material having the largest band gap is formed on the top of the light absorbing layer 240, and the material having the smallest band gap is formed. It is preferable that it is formed in a tandem method located at the bottom (substrate side).

In this case, the tandem solar cell means that solar cells having different energy band gaps are connected by using spacers (tunnel junction layers).

The quantum dot layer is formed of a quantum dot made of a III-V compound semiconductor. The quantum dots include InAs, GaAs, InGaAs, InAlAs, InAlGaAs, InSb, InGaSb, InAlSb, InAlGaSb, InAsN, InGaAsN, InAlbN, InGaSbN, InAlSbN, InAGaSbAl, InAGaSbAl InAlGaAsP may be formed.

The quantum dot layer may be formed using S-K (Stranski-Krastanov) method of growing quantum dots by self-assembling. In addition, quantum dots may be grown using atomic layer epitaxy (ALE) and droplet epitaxy.

The group III-V compound semiconductor layer is InAs, GaAs, InGaAs, InAlAs, InAlGaAs, InSb, InGaSb, InAlSb, InAlGaSb, InAsN, InAlGaAsN, InAlBn, InGaSbN, InAlSbN, InASbN, InASbN, InAP , Selected from the group consisting of InSbP, InGaSbP, InAlSbP and InAlGaAsP, Molecular beam epitaxy (MBE), Metal organic chemical vapor deposition (MOCVD), Liquid epitaxy (Liquid phase) epitaxy, hereinafter referred to as LPE), low temperature and high temperature treatment (LT-HT method) and the like.

A second semiconductor layer 250 is formed on the light absorbing layer 240. The second semiconductor layer 250 may mean an “n-type semiconductor layer” or a “p-type semiconductor layer”, and is typically As opposed to each other, the conductive properties are opposite to each other, so that the incident light is absorbed by the light absorbing layer in the solar cell structure to form a junction structure that can cause a photoelectric effect. For example, the p-type semiconductor may be doped with a group II component to a group III-V compound semiconductor, and the n-type semiconductor may be doped with a group IV component to a group III-V compound semiconductor. At this time, the impurity ion concentration ranges in the p-type and n-type semiconductors are not particularly limited.

The protective film 100 may be provided on the second semiconductor layer 250 or the upper electrode layer 251.

The structure of the protective film 100 has been described above in detail, and will be omitted to prevent the description of repeated contents. For the structure of the protective film 100 will be referred to the bar described above.

As will be described later in the following examples, as described above, when provided with a protective film 100 according to the present invention in a solar cell, by increasing the long-term stability of the solar cell by protecting the solar cell from the external environment, damage or damage In this case, only the protection film can be replaced, thereby reducing maintenance costs, and remarkably enhancing the effect of preventing light reflection and increasing light absorption, thereby increasing the energy conversion efficiency of the solar cell by 1 to 5%. .

Hereinafter, the present invention will be described in more detail with reference to examples and the like, but the scope and contents of the present invention are not limited or interpreted by the following examples. In addition, if it is based on the disclosure of the present invention including the following examples, it will be apparent that those skilled in the art can easily carry out the present invention, the results of which are not specifically presented experimental results, these modifications and modifications are attached to the patent It goes without saying that it belongs to the claims.

In addition, the experimental results presented below are only representative of the experimental results of the Examples and Comparative Examples, and the effects of each of the various embodiments of the present invention not explicitly set forth below will be described in detail in the corresponding sections.

Example 1-10. Preparation of Protective Film.

The prepolymer and crosslinker of the PDMS kit (Sylgard 184, Dow Corning) are mixed in a ratio of 10: 1 (by weight), and the bubbles generated in the mixture are vacuum chamber (~ 1.3 × 10 ⁻¹ pa, 20 minutes / air gun).

A Petri dish (d = 138 mm) was prepared, and 15 ml of the mixture was applied to the Petri dish to prepare several films having a thickness of 1 mm in advance. The film was prepared by heating at 95 ° C. for 1 hour to cure.

The film was attached on a glass substrate to form a base layer portion, and a film having a different thickness was attached on the base layer portion to form one surface layer portion. Subsequently, another film having the same thickness is attached on the surface layer of the first layer, and the same process is repeated to form one layer (Example 1), two layers (Example 2), three layers (Example 3), 4 Layers (Example 4), 5 layers (Example 5), 6 layers (Example 6), 7 layers (Example 7), 8 layers (Example 8), 9 layers (Example 9), 10 layers ( Example 10) to form a surface layer portion, to prepare a protective film consisting of multiple layers of a constant thickness. At this time, the glass substrate is removed after the protective film is completed as a support for forming a protective film, and only a protective film composed of a base portion and a surface layer portion is used.

At this time, without preparing a film of a predetermined thickness in advance, the mixture is applied to the base layer portion to a thickness of 1 mm and heated and cured at 95 ℃ for 1 hour, and the same process is repeated to surface layer having a plurality of layers By forming a, it is possible to manufacture a protective film consisting of a multi-layer of a constant thickness, but the method of manufacturing the film in advance, the method of attaching the layer layer is easy to control the thickness, and can shorten the time, in this experiment, the film in advance Was prepared and the method of attaching the layered layer was used.

Comparative Example 1. Single Layer Protective Film

The prepolymer and crosslinker of the PDMS kit (Sylgard 184, Dow Corning) are mixed in a ratio of 10: 1 (by weight), and the bubbles generated in the mixture are vacuum chamber (~ 1.3 × 10 ⁻¹ pa, 20 minutes / air gun used) to prepare a composition for preparing a protective film.

A petri dish (d = 138 mm) was prepared, and 15 ml of the mixture was applied to the petri dish to be 1 mm thick, heated at 95 ° C. for 1 hour to form a base layer, and formed of a single layer protective film. Was prepared.

Comparative Example 2. Protective Films with Different Thicknesses of Base and Surface Layers

4.4 ml was applied to a petri dish (d = 37.5 mm) and a cured film having a thickness of 4 mm was prepared. At this time curing was performed by heating at 95 ℃ for 1 hour.

By attaching the film having a thickness of 4 mm on the protective film prepared in Comparative Example 1, a surface layer part of a single layer having a different thickness from the base layer part was formed, and a protective film having a total thickness of 5 mm was prepared.

Comparative Example 3. A protective film having a double layer having a thickness of 2 mm

11.3 mL was applied to a petri dish (d = 85 mm), and several sheets having a cured 2 mm thickness were prepared. At this time curing was performed by heating at 95 ℃ for 1 hour.

On the protective film prepared in Comparative Example 1, a film having the thickness of 2 mm was attached to stack one layer of the surface layer, and a film having a thickness of 2 mm was attached to the surface layer of the first layer, respectively, to obtain a thickness of 2 mm. The protective film which has the surface layer part of two layers which has is manufactured.

Comparative Example 4 Protective Film-1 Having a Surface Layer of Different Thickness

A Petri dish (d = 138 mm) was prepared, and 15 ml of the mixture was applied to the Petri dish and 11.3 ml of a 1 mm thick film and a petri dish (d = 85 mm) were cured. Several films having a thickness of 2 mm were prepared. At this time curing was performed by heating at 95 ℃ for 1 hour.

On the protective film prepared in Comparative Example 1, by attaching a film having a thickness of 1 mm to laminate the surface layer of one layer, and repeating the process of attaching a film of 1 mm thick on the surface layer of the first layer 3 Three layers of surface layers in which sheets were layered were formed. A 2 mm thick film was attached to the top surface of the three layers to prepare a protective film having four surface layers consisting of 1 mm, 1 mm, 1 mm, and 2 mm.

Comparative Example 5 Protective Film-2 Having a Surface Layer of Different Thickness

A petri dish (d = 138 mm) was prepared, and 15 ml of the mixture was applied to the petri dish and 44.8 ml of a 1 mm thick film and petri dish (d = 138 mm) were cured. Several films with a thickness of 3 mm were prepared. At this time curing was performed by heating at 95 ℃ for 1 hour.

On the protective film prepared from Comparative Example 1, each layer having a thickness of 1 mm attached to each layer in three layers, and a film having a thickness of 3 mm on the upper surface of the layer is attached to 1 mm, 1 mm, 1 A protective film having four surface layer portions made of mm and 3 mm was prepared.

Comparative Example 6 Protective Film-3 Having a Surface Layer of Different Thickness

44.8 ml was applied to a petri dish (d = 138 mm), and several films having a thickness of 3 mm cured were prepared. At this time curing was performed by heating at 95 ℃ for 1 hour.

On the protective film prepared in Comparative Example 1, by attaching a film having a thickness of 3 mm to laminate the surface layer of one layer, and repeating the process of attaching a film having a thickness of 3 mm on the surface layer of the first layer By manufacturing three layers each having a thickness of 3 mm, to prepare a protective film having a surface layer consisting of three layers of 3 mm thickness.

Comparative Examples 7 to 12. Protective film having a pattern layer

1) Preparation of protective film composition

The prepolymer and crosslinker of the PDMS kit (Sylgard 184, Dow Corning) are mixed in a ratio of 10: 1 (by weight), and the bubbles generated in the mixture are vacuum chamber (~ 1.3 × 10 ⁻¹ pa, 20 minutes / air gun used) to prepare a composition for preparing a protective film.

In order to prepare the polymer composition for the pattern layer (h-PDMS), first, 2 g of VDT-731 (vinylmethylsiloxane-dimethylsiloxane copolymers terminated with trimethylsiloxy) of the h-PDMS kit (Gelest), SIP 6831.2LC (platinum-divinyltetramethyl-disiloxane complex in xylene 10.592 μl, SIT 7900.0 (1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane) 70.58 mg, HMS-301 (methylhydrosiloxane-dimethylsiloxane copolyers with trimethylsiloxy terminated) 0.58 g are mixed and mixed into the mixture The generated bubbles were removed by a vacuum chamber (˜1.3 × 10 −1 pa, 20 minutes / air gun used) to prepare a h-PDMS composition, which is a polymer composition for a pattern layer.

2) Conical Mold Preparation

Spherical polymer beads were coated with a monolayer using the Langmuir Blodgett technique on a silicon substrate. Thereafter, the diameter of the polymer beads was reduced by a dry etching process using an inductively coupled plasma and O ₂ gas. A chromium mask layer was then deposited in the gap between the reduced polymer beads using an electron beam deposition apparatus, and the polymer beads were removed from the mask layer using chloroform. Using the inductively coupled plasma, Ar, Cl ₂ gas, the site where the polymer beads escaped was prepared in a concave conical mold through a dry etching process.

3) Manufacture protective film of pattern layer

The protective film manufacturing composition prepared in step 1) was applied to the conical mold prepared through step 2) and cured. Specifically, the protective film manufacturing composition was applied at 6000 rpm and 100 sec in a spin coater to cover the concave patterned portion of the conical mold, and cured at 65 ° C. for 30 minutes to form a pattern layer. The h-PDMS composition was applied at 1000 rpm, 30 sec on the upper surface of the pattern layer, and cured at 95 ° C. for 1 hour to prepare a base layer portion. In order to prevent the collapse of the pattern layer was prepared by separating the protective film having the conical mold and the pattern layer in methanol solution. The layer thickness and pattern in each comparative example are put together in Table 1.

division Substrate thickness Pattern layer Pattern Size
(Diameter of polymer beads, nm) thickness Comparative Example 7 0.5 mm 0.39 PS 0.5 mm Comparative Example 8 0.5 mm 0.39 + 0.57 PS 0.5 mm Comparative Example 9 0.5 mm 0.57 PS 0.5 mm Comparative Example 10 1 mm 0.39 + 0.57 PS 0.7 mm Comparative Example 11 1 mm 0.57 PS 0.7 mm Comparative Example 12 1 mm 0.39 PS 0.7 mm

Experimental Example 1. Analysis of efficiency in GaAs cell

After attaching the protective films prepared from Comparative Examples 1 to 4 and Examples 1 to 5 on the upper surface of the GaAs solar cells, their solar cell efficiency (efficiency%) was compared. The efficiency of the solar cell was measured by analyzing the current-voltage curve data. After exposing the solar cell to light having a specific spectrum and irradiation intensity suggested by the IEC (International Electrotechnical Commision) standard, the solar cell was exposed to light. The current-voltage characteristic outputted by was measured. Using the reference solar cell (KS C IEC 60904-2), the irradiation intensity of artificial light source was set to 1-SUN, 100mW / cm ㅂ, AM1.5G, and xenon lamp (SAN-EI ELECTRIC Co., Ltd) .) Was used and measured using K730 solar cell IV parameter test software (McScience). Hereinafter, unless otherwise stated, the efficiency of the solar cell was measured using the method described above.

Each of the protective films of Comparative Examples 1 to 3 and Examples 1 to 5 was attached to the upper surface of a bulk solar cell having a size of 0.5 cm × 0.5 cm gallium arsenide (hereinafter referred to as GaAs) provided by the Korea Institute of Science and Technology. I was. The structure of the GaAs solar cell is n-GaAs buffer layer, n-GaInP layer, n-GaAs layer, p-GaAs layer, p-GaInP layer and AR layer (Si ₃ N ₄ ) from the n-GaAS substrate as shown in FIG. It consisted of Nothing was attached to the upper surface of the solar cell (control group, GaAs), or each of the protective films of Comparative Examples 1 to 3 and Examples 1 to 5 were attached.

Comparative Examples 1 to 3, Examples 1 to 5 of the protective film has an adhesive force on the bottom of the base portion, it is attached by simply contacting like a sticker without additional processing, it can be easily removed later contamination.

FIG. 5 is a photograph showing a structure of a GaAs solar cell in which a protective film is not attached in Experimental Example 1 (a) and a photograph of a state in which a protective film prepared in Example 2 is attached to a GaAs solar cell. , The protective film of the present invention is very excellent in transparency, it can be seen that does not adversely affect the light transmission of the solar cell at all.

6 is a graph showing the measured efficiency of the solar cell (efficiency%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 on the upper surface of the GaAs solar cell, the number of layers of the surface layer portion of the protective film It can be seen that the efficiency of the solar cell is increasing with increasing. The solar cell attached with nothing (bare (GaAs)) or with a protective film (Comparative Example 1) having only a base portion had the efficiency of 25%, but from the moment of attaching the protective film of Example 1 % Increased, and when the protective film of Example 5 attached, it was confirmed that the increase by more than 5%. In other words, it can be seen that the protective film according to the present invention not only protects the solar cell from the external environment but also significantly improves the efficiency by 1 to 5% or more. In the solar cell field, it is possible to achieve an efficiency increase of 1% from a solar cell having an optimized structure. In addition, the protective film of the present invention is very useful because it is easy to be attached and detached, can be removed when the contamination and newly replaced.

7 is a graph showing the measured efficiency of the solar cells (efficiency%) after attaching the protective film prepared from Comparative Examples 2, 3 and 4 on the upper surface of the GaAs solar cell, the total thickness of the protective film laminated In the case of the same, it can be seen that the degree of increase in efficiency varies by 2% or more depending on the thickness of the layer constituting the surface layer portion.

That is, even if they have the same material and the same total thickness, any one layer among the layers constituting the surface layer portion has a disadvantage in that an efficiency increase effect of 2% or more is not obtained when compared to bare (GaAs). .

Experimental Example 2 Efficiency Analysis in Solar Cell Si Cell (monocrystalline)

After attaching the protective film prepared from Comparative Examples 4 to 6 and Examples 4 to 10 on the upper surface of the si solar cell (monocrystalline), their solar cell efficiency (efficiency%) was compared.

Each of the protective films of Comparative Examples 4 to 6 and Examples 4 to 10 was attached (adhered) to the top surface of a Si solar cell (monocrystalline) bulk solar cell of 0.5 cm × 0.5 cm size purchased from Soleil Tech. The structure of the si solar cell (monocrystalline) is composed of n, p-metal finger, SiO₂ passivation, n, p-diffusion, n-type base, n ⁺ FSF, SiO₂ passivation, AR coating. Nothing was attached to the upper surface of the solar cell (control, bare (si)), or each of the protective films of Comparative Examples 4 to 6, Examples 4 to 10 were attached.

Comparative Examples 4 to 6, Examples 4 to 10 of the protective film has an adhesive force on the bottom of the base portion, it is attached by simply contacting like a sticker without additional processing, it can be easily removed in the future contamination.

FIG. 8 is a photograph of a si solar cell (monocrystalline) having no protective film attached in Experimental Example 2 and a photograph of a state in which the protective film prepared in Example 10 is attached on a si solar cell (monocrystalline). In the photograph (b), the protective film of Example 10 composed of a base layer portion of one layer and a surface layer portion of nine layers was laminated on the solar cell, but was confirmed to be still transparent.

FIG. 9 is a graph showing measurement results of solar cell efficiency (efficiency%) after attaching a protective film prepared in Examples 4 to 10 on an upper surface of a si solar cell (monocrystaliine), as shown in FIG. As the number of layers increased, the efficiency of the solar cell was significantly increased.

No adhesion (bare (si)) or 15% of the solar cell had the efficiency as it was, but increased by more than 1% from the moment of attaching the protective film of Example 4, the protective film of Example 10 It was confirmed that the case increased by more than 3%. In other words, it can be seen that the protective film according to the present invention not only protects the solar cell from the external environment but also significantly improves the efficiency by 1 to 3% or more. In the solar cell field, it is possible to increase the efficiency of even 1% from a solar cell having an optimized structure. In addition, the protective film of the present invention is very useful because it is easy to be attached and detached, can be removed when the contamination and newly replaced.

10 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Examples 4, 5, 8 and Comparative Examples 4 to 6 on the upper surface of the si solar cell (monocrystaliine), When the thickness of each layer of the surface layer part is the same (Example 4-8), it confirmed that efficiency increased by 15-> 17% or more. On the contrary, in Comparative Example 4-6 having the same material and the same total thickness as in Example 4-8, the thickness of each layer was completely different, it was confirmed that it was 1% or more lower than the example.

In other words, it was confirmed that any one of the layers constituting the surface layer part has a limit of obtaining an efficiency increase of 1% or more compared to bare (si) when the thickness deviates from 1.5 mm. The protective film of the present invention has an efficiency increase effect of 2% or more, even if the internal structure of the protective film is changed even if the same material and the same total thickness, the problem that can achieve only half the efficiency increase effect of the solar cell Occurs.

Experimental Example 3 Efficiency Analysis in Solar Cell si Module

After attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 on the upper surface of the solar cell si module (module), their solar cell efficiency (efficiency%) was compared.

The 9 cm × 7 cm solar cell si module in which four pieces of 9 cm × 1.6 cm sized pieces of the protective films of Comparative Examples 1 and 1 to 5 were each connected in series with a 2 mm gap. The module was attached (adhered) to the top surface. The structure of the solar cell si module is composed of metal backing, p-Si, p-n junction, n-Si, AR coating, metal contact, PVC coating. Nothing was attached to the top surface of the solar cell (control, si (module)), or Comparative Examples 1, 1 to 5 of each of the protective films were attached.

The protective film of Comparative Example 1, Examples 1 to 5 has an adhesive force on the bottom of the base portion, it is attached by simply contacting like a sticker without additional processing, it can be easily removed in the future contamination.

11 is a photograph of a solar cell si module (module) is not attached to the protective film in Experimental Example 5 (a) and the appearance of the protective film prepared from Example 5 attached to the solar cell si module (module) In the photograph (b) taken, it was confirmed that when the actual protective film is applied, the transparency of the solar cell is not impaired at all. In other words, the protective film of the present invention can protect the solar cell from external physical and chemical effects. When the protective film is damaged by an external environment, only the protective film may be removed and replaced, and the protective film may be easily attached and detached through adhesion, thereby reducing the cost much more than replacing the solar cell. .

FIG. 12 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Comparative Example 1 and Examples 1 to 5 on the upper surface of the solar cell si module (module). As the number of layers on the surface of the protective film increases, the efficiency of the solar cell is significantly increased.

When nothing was attached (bare (si)), or when the protective film of Comparative Example 1 was attached, it had the efficiency of 15.5%, but the efficiency began to increase from the moment when the protective film of Example 1 was attached, When the protective film of 5 was attached it was confirmed that the increase by more than 1%. In other words, it can be seen that the protective film according to the present invention not only protects the solar cell from the harmful environment outside, but also significantly improves the energy conversion efficiency of the solar cell by 1% or more. In the solar cell field, it is possible to increase the efficiency of even 0.1% from a solar cell having an optimized structure. In addition, the protective film of the present invention is very useful because it is easy to be attached and detached, can be removed when the contamination and newly replaced.

FIG. 13 is a graph showing measurement results of solar cell reflectivity (reflectance%) after attaching the protective films prepared from Comparative Example 1 and Examples 1 to 10 on the upper surface of the GaAs solar cell. In Comparative Example 1, Examples 1 to 10 are shown in the direction of the arrow starting from the blue line. In the present invention, the reflectance of the solar cell was measured using an IPCE mesurement system.

According to Figure 13 it was confirmed that the reflectivity of the solar cell decreases as the number of layers of the surface layer of the protective film increases. It was confirmed that the reflectivity was reduced by about 5% in the wavelength range of 350 ~ 400 nm than when the protective film of Comparative Example 1 attached. That is, the protective film according to the present invention not only protects the solar cell from the external environment, but also reduces the reflectivity to prevent light reflected from the solar cell and increases the light absorption rate, thereby increasing the energy conversion efficiency of the solar cell (FIG. 6 and 12) was significantly improved by 1 to 5% or more. In the solar cell field, it is very significant that even an efficiency of only 0.1% can be increased from a solar cell having an optimized structure, and the protective film of the present invention has excellent antireflection and light absorption increase effects. . That is, the protective film of the present invention has a variety of excellent functions, such as the material and structure is simple, easy to attach and detach, can be removed and replaced when contaminated, to increase the efficiency of the solar cell.

Experimental Example 4. Efficiency Analysis in Solar Cell GaAs

14 is a cross-sectional view showing a structure when the protective film prepared from Comparative Examples 7 to 12 is attached to the surface of a solar cell (GaAs solar cell). (a) is to attach a protective film prepared from Comparative Example 7, (b) is to attach a protective film prepared from Comparative Example 8, (c) is to attach a protective film prepared from Comparative Example 9. , (d) is to attach a protective film prepared from Comparative Example 10, (e) is to attach a protective film prepared from Comparative Example 11, (f) is to attach a protective film prepared from Comparative Example 12 will be.

15 is a graph showing the solar cell efficiency (efficiency%) after attaching the protective film prepared from Comparative Example 1, Examples 1 to 5 and Comparative Examples 7 to 12 on the upper surface of the GaAs solar cell.

The efficiency of the solar cell was measured by analyzing the current-voltage curve data. After exposing the solar cell to light having a specific spectrum and irradiation intensity suggested by the IEC (International Electrotechnical Commision) standard, the solar cell was exposed to light. The current-voltage characteristic outputted by was measured. Using the reference solar cell (KS C IEC 60904-2), the irradiation intensity of artificial light source was set to 1-SUN, 100mW / cm ㅂ, AM1.5G, and xenon lamp (SAN-EI ELECTRIC Co., Ltd) .) Was used and measured using K730 solar cell IV parameter test software (McScience).

As shown in Figure 15, the protective film produced from the embodiment and the comparative example, but using the same material, there is a difference in the presence or absence of the pattern layer, each of them compared the efficiency in the bonded solar cell. It can be seen that the efficiency of the solar cell in which the protective films of Examples 1 to 5 are laminated is significantly increased, compared to Comparative Examples 7 to 12, in which the pattern layer is present. It can be seen that the efficiency of the solar cell increased by at least 1% and up to 5%. Whereas the protective film of Examples 1 to 5 is thicker than the protective film of Comparative Examples 7 to 12 and the structure is simpler, the protective film of the present invention without a pattern layer significantly improves the function of the solar cell. It is a range of unexpected things.

Looking at the results of measuring the energy conversion efficiency for the solar cell (flat) with a protective film prepared from Examples 1 to 5 and the solar cell (pattern) with a protective film prepared from Comparative Examples 1, 7 to 12 , Solar cell without a protective film at all has a efficiency of less than 25%, and a solar cell with a protective film (comparative example 1) having only a base portion has an efficiency of 25%, the pattern layer In the case of a solar cell having a protective film (Comparative Examples 7 to 12) having a confirmed that it has an efficiency of up to 26 ~ 27%. On the contrary, the solar cells to which the protective films of Examples 1 to 5 of the present invention are attached have been found to increase energy conversion efficiency from at least 26% efficiency to 30% efficiency. That is, it was confirmed that the energy conversion efficiency increased by about 1% to 5% or more.

In addition, it was confirmed that the solar cell (Example 1-5) of the present invention increased about 1 to 3.5% energy conversion efficiency compared to the solar cell (Comparative Example 7-12) using a protective film having a pattern layer.

At this time, the solar cell (GaAs) used had an AR layer and had an improved structure for high energy conversion efficiency, and had already achieved an energy conversion efficiency increase of 25%.

That is, the present invention indicates that even if a solar cell having an improved structure is simply attached to the protective film according to the present invention, energy conversion efficiency can be additionally increased by at least 1% and at most 5% at a time, but only 0.1%. The increase of the effect of the present invention has a very significant meaning in the field of solar cells, which has a significant meaning even with an increase in energy conversion efficiency.

In addition, the protective film of the present invention has the effect of preventing light reflection and increasing the light absorption rate, increasing the energy conversion efficiency of the solar cell by up to 5%, as well as the simple structure and manufacturing process, and the protective effect of the solar cell. In that it has the advantage of easy removal and removal, it can be seen that a significantly superior effect is achieved.

That is, in the finally completed solar cell, the protective film according to the present invention (Example 1-5) is an effect of increasing the additional energy conversion efficiency of the degree having a greater meaning than the protective film having a pattern layer (Comparative Example 7-12) In the protective film according to the present invention (Example 1-5), it can be seen that it shows a remarkably excellent energy conversion efficiency having a great meaning of about 1% or more up to about 5%.

In addition, the structure is simple, and the manufacturing process is easy and simple, compared with the anti-reflective effect, and has an effect of increasing the light absorption rate, protects the solar cell from the external environment, there is an advantage that it is easily removable to replace.

Conventionally, the solar cell itself is provided with a pattern layer or an anti-reflection film, and if the surface or part of the solar cell is contaminated by the external environment, there is a need to purchase or install the entire solar cell again. The present invention by providing a protective film having a detachable function to solve this problem, while protecting the solar cell from the external environment, to prevent light reflection and increase the light absorption, increase the efficiency of the solar cell 1 to 5%, If contaminated, it can be easily replaced, which has the advantage of reducing costs.

In the case of a protective film formed of a pattern layer, not only an additional manufacturing process is required to form a pattern, but a protective film formed of a pattern layer has a slight effect of increasing efficiency as the thickness increases, but rather a relatively low efficiency problem. May occur.

Claims (10)

A base portion having adhesion; And
A protective film for a solar cell provided with a surface layer portion which is laminated on one surface of the base layer portion and includes at least one layer having a thickness of 0.1 to 1.5 mm.
The method of claim 1,
The base portion is polydimethylsiloxane (PDMS), polycarbonate (PC), polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), Ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP) protective film for solar cells, characterized in that any one selected from the group consisting of.
The method of claim 1,
The surface portion is polydimethylsiloxane (PDMS), polycarbonate (PC), polyurethane (PUR), acrylate, pulley acrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), Ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP) protective film for solar cells, characterized in that any one selected from the group consisting of.
The method of claim 1,
The surface layer is a protective film for solar cells, characterized in that provided with the number of layers selected from 1 to 20 layers.
The method of claim 1,
Each layer of the surface layer portion is a protective film for solar cells, characterized in that having the same thickness.
The method of claim 1,
The protective film for solar cells is a protective film for solar cells, characterized in that 35 to 40% reflectivity of light of 350 to 400 nm wavelength.
I) coating and curing the composition for preparing a protective film to prepare a base portion; And
Ⅱ) applying a layer of the protective film manufacturing composition on one side of the base portion and hardened to prepare a layer having a thickness of 0.1 to 1.5 mm, repeating this process to form a surface layer consisting of at least one layer; Method of manufacturing a protective film for batteries.
a) applying a composition for preparing a protective film, curing to prepare a film having a constant thickness, and attaching the film to a layer layer to prepare a solar cell protective film composed of a base layer portion and a surface layer portion having at least one or more layers; Method for manufacturing a protective film for solar cells.
The method according to claim 7 or 8,
The protective film manufacturing composition comprises a polysiloxane-based polymer, a curing agent, a silane coupling agent and an organic solvent,
1 to 20 parts by weight of a siloxane curing agent, based on 100 parts by weight of the polysiloxane polymer; Method for producing a protective film for solar cells comprising 0.005 to 5 parts by weight of a silane coupling agent selected from alkoxy silane compounds.
The method according to claim 7 or 8,
The curing method of the solar cell protective film, characterized in that carried out for 90 to 100 ℃, 0.5 to 2 hours.

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