KR102253838B1 - Solar cell module and back sheet used for the same - Google Patents

Abstract

A solar cell module according to an embodiment of the present invention includes at least one solar cell; A sealing material surrounding and sealing the solar cell; And a rear sheet positioned on the rear surface of the solar cell on the sealing material. The rear sheet may include a base member; A first resin layer positioned on one surface of the base member; And a first adhesive layer that bonds them between the base member and the first resin layer and includes an adhesive material and a flame retardant material.

Description

Solar cell module and back sheet used therein {SOLAR CELL MODULE AND BACK SHEET USED FOR THE SAME}

The present invention relates to a solar cell module and a rear sheet used therein.

Recently, as existing energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing. Among them, solar cells are in the spotlight as next-generation cells that convert solar energy into electrical energy.

Since such a solar cell needs to be exposed to an external environment for a long period of time, it is manufactured in a module form by a packaging process for protecting the solar cell. Since the solar cell module manufactured in this way needs to generate power in various environments, it must have high long-term reliability so that it can generate power for a long time in various environments. In addition, flame retardancy regulations for solar cell modules are being reinforced so as to prevent fire from spreading in the event of a fire or the like, and it is required to improve the flame retardancy of the solar cell module.

The present invention is to provide a rear sheet having excellent flame retardancy and a solar cell module including the same.

A solar cell module according to an embodiment of the present invention includes at least one solar cell; A sealing material surrounding and sealing the solar cell; And a rear sheet positioned on the rear surface of the solar cell on the sealing material. The rear sheet may include a base member; A first resin layer positioned on one surface of the base member; And a first adhesive layer that bonds them between the base member and the first resin layer and includes an adhesive material and a flame retardant material.

Solar cell module according to another embodiment of the present invention, at least one solar cell; A sealing material surrounding and sealing the solar cell; And a rear sheet positioned on the rear surface of the solar cell on the sealing material. The back sheet includes a plurality of layers and at least one adhesive layer for bonding the plurality of layers. At least one of the at least one adhesive layer includes an adhesive material and a flame retardant material.

A rear sheet according to an embodiment of the present invention is a rear sheet for a solar cell module used in a solar cell module, comprising: a base member; A first resin layer positioned on one surface of the base member; And a first adhesive layer that bonds them between the base member and the first resin layer, and includes an adhesive material and a flame retardant material.

According to this embodiment, the adhesive layer of the rear sheet includes a flame retardant material. Accordingly, it is possible to improve flame retardancy by a simple method, while preventing deterioration of properties such as the base member and the resin layer constituting the rear sheet.

1 is an exploded perspective view of a solar cell module according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.
3 is a cross-sectional view of a solar cell according to an embodiment of the present invention.
4 is a plan view of the solar cell shown in FIG. 3.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to these embodiments and may be modified in various forms.

In the drawings, in order to clearly and briefly describe the present invention, illustration of parts irrelevant to the description is omitted, and the same reference numerals are used for identical or extremely similar parts throughout the specification. In addition, in the drawings, the thickness and width are enlarged or reduced in order to clarify the description. However, the thickness and width of the present invention are not limited to those shown in the drawings.

In addition, when a certain part "includes" another part throughout the specification, the other part is not excluded and other parts may be further included unless otherwise stated. Further, when a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly above", but also the case where the other part is located in the middle. When a part such as a layer, a film, a region, or a plate is "directly over" another part, it means that no other part is located in the middle.

Hereinafter, a solar cell module according to an embodiment of the present invention and a rear sheet used therein will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a solar cell module according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

1 and 2, the solar cell module 100 according to an embodiment of the present invention includes at least one solar cell 150, a sealing material 130 surrounding and sealing the solar cell 150, and It includes a rear sheet 200 positioned on the rear surface of the solar cell 150 on the sealing material 130. At this time, the back sheet 200 includes adhesive layers 231 and 232 including a flame retardant material. In addition, it may include a front substrate 110 positioned on the front surface of the solar cell 150 on the sealing material 130. This will be described in more detail.

First, the solar cell 150 is formed including a photoelectric conversion unit that converts solar energy into electrical energy, and an electrode electrically connected to the photoelectric conversion unit. In this embodiment, as an example, a photoelectric conversion unit including a semiconductor substrate (eg, a silicon wafer) and a conductivity type region may be applied. The solar cell 150 having such a structure will be described in detail with reference to FIGS. 3 and 4, and then the solar cell module 100 will be described in detail with reference to FIG. 1.

3 is a cross-sectional view of a solar cell according to an embodiment of the present invention, and FIG. 4 is a plan view of the solar cell shown in FIG. 3. In FIG. 4, the semiconductor substrate 152 and the first and second electrodes 42 and 44 are mainly illustrated.

Referring to FIG. 3, the solar cell 150 according to the present embodiment includes a semiconductor substrate 152 including a base region 10, a conductivity type region 20, 30, a base region 10, and/or Alternatively, it includes electrodes 42 and 44 connected to the conductive regions 20 and 30, respectively. Hereinafter, the first conductivity type region is referred to as the emitter region 20 and the second conductivity type region is referred to as the rear electric field region 30. The terms of the first and second conductivity type regions are merely used for distinction, and the present invention is not limited thereto. In addition, the first electrode 42 is electrically connected to the emitter region 20, and the second electrode 44 is electrically connected to the base region 10 or the rear electric field region 30. In addition, passivation layers 22 and 32, anti-reflection layers 24, and the like may be further formed. This will be described in more detail.

The semiconductor substrate 152 includes a region in which the conductive regions 20 and 30 are formed and a base region 10 which is a region in which the conductive regions 20 and 30 are not formed. The base region 10 may be formed of silicon including a first conductivity type impurity, for example. As silicon, single crystal silicon (eg, a silicon wafer) or polycrystalline silicon may be used, and the first conductivity type impurity may be p-type or n-type.

When the base region 10 has a p-type, the base region 10 is made of monocrystalline or polycrystalline silicon doped with Group III elements such as boron (B), aluminum (Al), gallium (Ga), and indium (In). Can be done. When the base region 10 has n-type, the base region 10 is made of monocrystalline or polycrystalline silicon doped with group 5 elements such as phosphorus (P), arsenic (As), bismuth (Bi), antimony (Sb), etc. Can be done. Various materials other than the above-described materials may be used for the base region 10.

In this case, the base region 10 may have an n-type impurity as a first conductivity-type impurity. Then, the emitter region 20 forming the pn junction with the base region 10 has a p-type. When light is irradiated to the pn junction, electrons generated by the photoelectric effect move toward the second surface (hereinafter, "rear surface") of the semiconductor substrate 152 and are collected by the second electrode 44, and holes are collected by the semiconductor substrate ( It moves toward the front side of 152 and is collected by the first electrode 42. This generates electrical energy. Then, holes, which have a slower moving speed than electrons, move to the front surface of the semiconductor substrate 152 rather than the rear surface, thereby improving conversion efficiency. However, the present invention is not limited thereto, and the base region 10 and the rear electric field region 30 may have a p-type and the emitter region 20 may have an n-type.

The front surface and/or the rear surface of the semiconductor substrate 152 may be textured to have irregularities in the shape of a pyramid or the like. When unevenness is formed on the front surface of the semiconductor substrate 152 by such texturing and the surface roughness is increased, the reflectance of light incident through the front surface of the semiconductor substrate 152 or the like can be lowered. Accordingly, the amount of light reaching the pn junction formed at the interface between the base region 10 and the emitter region 20 can be increased, thereby minimizing light loss. However, the present invention is not limited thereto, and it is also possible that unevenness due to texturing may not be formed on the front and rear surfaces of the semiconductor substrate 152.

An emitter region 20 having a second conductivity type opposite to the base region 10 may be formed on the front side of the semiconductor substrate 152. When the emitter region 20 is n-type, it may be made of single crystal or polycrystalline silicon doped with phosphorus, arsenic, bismuth, and antimony, and when it is p-type, aluminum (Al), gallium (Ga), and indium (In) are doped. It may be made of single crystal or polycrystalline silicon.

In the drawing, it is illustrated that the emitter region 20 has a homogeneous structure having a uniform doping concentration as a whole. However, the present invention is not limited thereto. Thus, in another embodiment, the emitter region 20 may have a selective structure. In the selective structure, a portion of the emitter region 20 adjacent to the first electrode 42 may have a high doping concentration and a low resistance, and other portions of the emitter region 20 may have a low doping concentration and a high resistance. As a structure of the emitter region 20, various structures other than this may be applied.

In this embodiment, a doped region formed by doping a second conductivity type impurity on the front side of the semiconductor substrate 152 constitutes the emitter region 20. However, the present invention is not limited thereto, and the emitter region 20 may be formed of an amorphous, microcrystalline, or polycrystalline semiconductor layer formed as a separate layer on the entire surface of the semiconductor substrate 152. Other variations are possible.

A passivation film 22 and an antireflection film 24 are sequentially formed on the semiconductor substrate 152, more precisely, on the emitter region 20 formed on the semiconductor substrate 152, and the first electrode 42 is formed of the passivation film ( 22) and through the anti-reflection film 24 (ie, through the opening 104) and in contact with the emitter region 20.

The passivation film 22 and the antireflection film 24 are formed substantially over the entire front surface of the semiconductor substrate 152 except for the portion corresponding to the first electrode 42 (more precisely, the portion where the opening 104 is formed). Can be.

The passivation film 22 is formed in contact with the emitter region 20 to passivate defects present in the surface or bulk of the emitter region 20. Accordingly, the open-circuit voltage (Voc) of the solar cell 150 may be increased by removing the recombination sites of minority carriers. The antireflection film 24 reduces reflectance of light incident on the front surface of the semiconductor substrate 152. Accordingly, the reflectance of light incident through the front surface of the semiconductor substrate 152 is lowered, thereby increasing the amount of light reaching the pn junction formed at the interface between the base region 10 and the emitter region 20. Accordingly, the short-circuit current Isc of the solar cell 150 may be increased. In this way, the open-circuit voltage and short-circuit current of the solar cell 150 may be increased by the passivation film 22 and the anti-reflection film 24 to improve the efficiency of the solar cell 150.

The passivation layer 22 may be formed of various materials. As an example, the passivation film 22 is a silicon nitride film, a silicon nitride film containing hydrogen, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, MgF ₂ , ZnS, TiO ₂ and any one single film selected from the group consisting of _{CeO 2 or} It is possible to have a multilayer structure in which two or more films are combined. For example, when the emitter region 20 has an n-type, the passivation film 22 may include a silicon oxide film or a silicon nitride film having a fixed positive charge, and the emitter region 20 has a p-type. In this case, it may include an aluminum oxide film or the like having a fixed negative charge.

The anti-reflection film 24 may be formed of various materials. As an example, the antireflection film 24 is a silicon nitride film, a silicon nitride film containing hydrogen, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, MgF ₂ , ZnS, TiO ₂ and any one single film selected from the group consisting of _{CeO 2 or 2} It is possible to have a multilayer structure in which two or more films are combined. For example, the antireflection layer 24 may include silicon nitride.

However, the present invention is not limited thereto, and it goes without saying that the passivation layer 22 and the antireflection layer 24 may include various materials. In addition, it is possible that one of the passivation film 22 and the antireflection film 24 performs the antireflection role and the passivation role together so that the other is not provided. Alternatively, various films other than the passivation film 22 and the antireflection film 24 may be formed on the semiconductor substrate 152. Other variations are possible.

The first electrode 42 is the emitter region 20 through the passivation film 22 and the opening 104 formed in the antireflection film 24 (that is, through the passivation film 22 and the antireflection film 24). Is electrically connected to The first electrode 42 may be formed of various materials to have various shapes. The shape of the first electrode 42 will be described later with reference to FIG. 4.

On the rear side of the semiconductor substrate 152, a rear electric field region 30 having the same first conductivity type as that of the base region 10 and including a first conductivity type impurity at a higher doping concentration than the base region 10 is formed. do. The rear electric field region 30 may be formed of a doped region formed by doping a first conductivity type impurity on the rear side of the semiconductor substrate 152. However, the present invention is not limited thereto, and the rear electric field region 30 may be formed of an amorphous, microcrystalline, or polycrystalline semiconductor layer separately formed on the rear surface of the semiconductor substrate 152. Other variations are possible.

In this embodiment, it is illustrated that the rear electric field region 30 has a homogeneous structure having a uniform doping concentration as a whole. However, the present invention is not limited thereto. Accordingly, in another embodiment, the rear electric field region 30 may have a selective structure. In the selective structure, a portion of the rear electric field region 30 adjacent to the second electrode 44 may have a high doping concentration and a low resistance, and other portions may have a low doping concentration and a high resistance. In another embodiment, the rear electric field region 30 may have a local structure. In the localized structure, the rear electric field region 30 may be formed locally corresponding to the portion where the second electrode 44 is formed.

A passivation film 32 is sequentially formed on the rear surface of the semiconductor substrate 152, more precisely, on the rear electric field region 30 formed on the semiconductor substrate 152, and the second electrode 44 penetrates the passivation film 32. To the rear electric field region 30 (ie, through the opening 102).

The passivation layer 32 may be formed substantially on the entire rear surface of the semiconductor substrate 152 except for a portion corresponding to the second electrode 44 (more precisely, a portion in which the opening 102 is formed).

The passivation film 32 is formed in contact with the rear electric field region 30 to passivate defects existing in the surface or bulk of the rear electric field region 30. Accordingly, the open-circuit voltage (Voc) of the solar cell 150 may be increased by removing the recombination sites of minority carriers.

The passivation layer 32 may be formed of various materials. As an example, the passivation film 32 is a silicon nitride film, a silicon nitride film containing hydrogen, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, MgF ₂ , ZnS, TiO ₂ and any one single film selected from the group consisting of _{CeO 2 or 2} It is possible to have a multilayer structure in which two or more films are combined. As an example, the passivation layer 32 may include a silicon oxide layer or a silicon nitride layer having a fixed positive charge when the rear electric field region 30 has an n-type, and the rear electric field region 30 has a p-type. In this case, it may include an aluminum oxide film or the like having a fixed negative charge.

However, the present invention is not limited thereto, and it goes without saying that the passivation layer 32 may include various materials. Alternatively, various films other than the passivation film 32 may be formed on the rear surface of the semiconductor substrate 152. Other variations are possible.

The second electrode 44 is electrically connected to the rear electric field region 30 through the opening 102 formed in the passivation layer 32. The second electrode 44 may be formed of various materials to have various shapes.

Referring to FIG. 4, the first and second electrodes 42 and 44 may include a plurality of finger electrodes 42a and 44a spaced apart from each other while having a constant pitch. In the drawings, the finger electrodes 42a and 44a are parallel to each other and parallel to the edge of the semiconductor substrate 152 is illustrated, but the present invention is not limited thereto. In addition, the first and second electrodes 42 and 44 may include busbar electrodes 42b and 44b formed in a direction crossing the finger electrodes 42a and 44a to connect the finger electrodes 42a and 44a. have. Only one of the bus electrodes 42b and 44b may be provided, or a plurality of bus electrodes 42b and 44b may be provided while having a pitch greater than that of the finger electrodes 42a and 44a as shown in FIG. 4. In this case, the widths of the busbar electrodes 42b and 44b may be larger than the widths of the finger electrodes 42a and 44a, but the present invention is not limited thereto and may have the same or smaller widths.

When viewed in cross section, both the finger electrode 42a and the busbar electrode 42b of the first electrode 42 may be formed through the passivation layer 22 and the antireflection layer 24. That is, the opening 104 may be formed to correspond to both the finger electrode 42a and the busbar electrode 42b of the first electrode 42. In addition, both the finger electrode 44a and the bus bar electrode 44b of the second electrode 44 may be formed through the passivation layer 32. That is, the opening 102 may be formed to correspond to both the finger electrode 44a and the busbar electrode 44b of the second electrode 44. However, the present invention is not limited thereto. As another example, the finger electrode 42a of the first electrode 42 is formed through the passivation film 22 and the antireflection film 24, and the busbar electrode 42b is formed by the passivation film 22 and the antireflection film 24. ) Can be formed above. In addition, the finger electrode 44a of the second electrode 44 may be formed through the passivation layer 32, and the busbar electrode 44b may be formed on the passivation layer 32.

In this embodiment, the first and second electrodes 42 and 44 of the solar cell 150 have a constant pattern, so that the solar cell 150 receives double-sided light through which light can be incident on the front and rear surfaces of the semiconductor substrate 152. It has a bi-facial structure. Accordingly, the amount of light used by the solar cell 150 may be increased, thereby contributing to the improvement of the efficiency of the solar cell 150.

In the drawing, it is illustrated that the first electrode 42 and the second electrode 44 have the same shape. However, the present invention is not limited thereto, and the width and pitch of the finger electrode and the bus bar electrode of the first electrode 42 may be determined by the width of the finger electrode 44a and the bus bar electrode 44b of the second electrode 44, It can have different values such as pitch. In addition, the first electrode 42 and the second electrode 44 may have different shapes, and other various modifications are possible.

In the above description, an example of the solar cell 150 has been described with reference to FIGS. 3 and 4. However, the present invention is not limited thereto, and the structure and method of the solar cell 150 may be variously modified. For example, the solar cell 150 may be applied with a photoelectric conversion unit having various structures such as using a compound semiconductor or a dye-sensitizing material.

Referring back to FIGS. 1 and 2, in the present embodiment, a plurality of solar cells 150 are provided, and a plurality of solar cells 150 may be electrically connected in series, parallel, or in series by a ribbon 142. have. Specifically, the ribbon 142 includes a first electrode formed on the front surface of the solar cell 150 (reference numeral 42 in FIGS. 3 and 4), and a second electrode formed on the rear surface of another adjacent solar cell 150 (FIG. 3). And reference numeral 44 of FIG. 4 may be connected by a tabbing process. The tabbing process is performed by applying a flux to the electrodes 42 and 44 of the solar cell 150, placing the ribbon 142 on the electrodes 42 and 44 to which the flux has been applied, and then performing a firing process. Can be. The flux is for removing the oxide film that interferes with soldering, and does not have to be included.

Alternatively, after attaching a conductive film (not shown) between the solar cell 150 and the ribbon 142, a plurality of solar cells 150 may be connected in series or in parallel by thermal compression. The conductive film (not shown) may be one in which conductive particles formed of gold, silver, nickel, copper, etc. having excellent conductivity are dispersed in a film formed of an epoxy resin, an acrylic resin, a polyimide resin, a polycarbonate resin, or the like. When the conductive film is compressed while applying heat, conductive particles are exposed to the outside of the film, and the solar cell 150 and the ribbon 142 may be electrically connected by the exposed conductive particles. When the plurality of solar cells 150 are connected to each other and modularized by a conductive film (not shown) as described above, the process temperature may be lowered, thereby preventing the solar cells 150 from being warped.

In addition, the bus ribbon 145 alternately connects both ends of the ribbon 142 of one row of solar cells 150 (ie, solar cell strings) connected by the ribbon 142. The bus ribbon 145 may be disposed in a direction crossing the end of the solar cell 150 forming one row. The bus ribbon 145 may be connected to a junction box (not shown) that collects electricity produced by the solar cell 150 and prevents electricity from flowing back.

However, the present invention is not limited thereto, and a connection structure between the solar cells 150, a connection structure between the solar cell 150 and an external connection structure, etc. may be variously modified. In addition, the solar cell module 100 may not include a plurality of solar cells 150 and may be configured as one solar cell 150.

The sealing material 130 may include a first sealing material 131 located on the front surface of the solar cell 150 and a second sealing material 132 located on the rear surface of the solar cell 150. The first sealing material 131 and the second sealing material 132 block moisture or oxygen that may adversely affect the solar cell 150 and allow the elements of the solar cell module 100 to be chemically bonded. The rear sheet 200, the second sealing material 132, the solar cell 150, the first sealing material 131, and the front substrate 110 are sequentially placed, and heat and/or pressure are applied to the solar cell by a lamination process. The battery module 100 can be integrated.

The first sealing material 131 and the second sealing material 132 may be ethylene vinyl acetate copolymer resin (EVA), polyvinyl butyral, silicon resin, ester resin, olefin resin, or the like. However, the present invention is not limited thereto. Accordingly, the first and second sealing materials 131 and 132 may be formed by a method other than lamination using various other materials. At this time, the first and second sealing materials 131 and 132 have light transmittance so that light incident through the rear sheet 200 or light reflected from the rear sheet 200 is re-incident to the solar cell 150. I can.

The front substrate 110 is positioned on the first sealing material 131 to constitute the front surface of the solar cell module 100. The front substrate 110 may be made of a material having an intensity capable of protecting the solar cell 150 from external impacts and a light transmittance capable of transmitting light such as sunlight. For example, the front substrate 110 may be formed of a glass substrate or the like. In this case, the front substrate 110 may be formed of a tempered glass substrate to improve strength, and various modifications may be made, such as additionally including various materials capable of improving other various properties. Alternatively, the front substrate 110 may be a sheet or film made of a resin or the like. That is, the present invention is not limited to the material of the front substrate 110, and the front substrate 110 may be formed of various materials.

The rear sheet 200 is a layer that protects the solar cell 150 from the rear surface of the solar cell 150, and may perform waterproofing, insulating, and UV-blocking functions. And in this embodiment, the rear sheet 200 may have excellent flame retardancy by including the adhesive layers 231 and 232 including a flame retardant material.

More specifically, the rear sheet 200 is formed on the base member 210 and one surface of the base member 210 (for example, a surface adjacent to the solar cell 150 or the sealing material 130 in the base member 210). It includes a first resin layer 221 positioned, and a first adhesive layer 231 bonding them between the base member 210 and the first resin layer 221. And the rear sheet 200 is located on the other side of the base member 210 (for example, a surface far away from the solar cell 150 or the sealing material 130 from the base member 210 or a surface located outside). A second resin layer 222 and a second adhesive layer 232 bonding them between the base member 210 and the second resin layer 222 may be included. Here, at least one of the first adhesive layer 231 and the second adhesive layer 232 may include a flame retardant material. For reference, in the present specification, the first resin layer 221 and the second resin layer 222, and the first adhesive layer 231 and the second adhesive layer 232 are only terms used to distinguish them from each other. The positions of the resin layers 221 and 222 and the adhesive layers 231 and 232 are not specified.

The base member 210 serves to support the first resin layer 221 and the second resin layer 222. In addition, the base member 210 may have insulating properties, thereby improving insulating properties. The base member 210 may include resin, for example, may include polyester. Polyester is suitable for protecting the solar cell 150 because of its excellent mechanical properties, thermal properties, electrical properties, moldability, and chemical resistance.

In this case, the polyester may be a general polyester or water-resistant polyester. When used for a long period of time, a general polyester may cause a problem of deteriorating mechanical properties due to hydrolysis. In consideration of this, water-resistant polyester can be used. The water-resistant polyester can be prepared by adding various substances (for example, a phosphate of an alkali metal or alkaline earth metal, an inorganic ginseng salt, or a suitable oligomer) to reduce the hydrolysis property to the polyester. Alternatively, it may be prepared by controlling the molecular weight of polyester. In this case, the molecular weight of the water-resistant polyester may be approximately 8,000 to 10,000. Various films, sheets, etc. known as the base member 210 including general polyester (molecular weight of approximately 6,000 to 8,000) or water-resistant polyester may be used.

In this case, polyethylene terephtalate (PET) may be included as polyester. Polyethylene terephthalate is a saturated polyester resin obtained by the condensation reaction of terephthalic acid (HOOC—COOH) and ethylene glycol, and is excellent in heat resistance, weather resistance, insulation, and mechanical strength. In particular, the molding shrinkage is as small as 0.1% to 0.6%, and it is possible to prevent the rear sheet 200 from being deformed by heat.

As the base member 210, the resin prepared in the form of a sheet (or film) by various methods may be used. However, the present invention is not limited thereto, and the base member 210 may be manufactured by various methods.

The thickness of the base member 210 may be 100um to 250um. When the thickness of the base member 210 is less than 100 μm, it may be difficult to have sufficient electrical insulation, moisture barrier, and mechanical properties. When the thickness of the base member 210 exceeds 250 um, handling is inconvenient and may cause an increase in unit cost. However, the present invention is not limited thereto, and the thickness of the base member 210 may vary depending on the material and thickness of the first and/or second resin layers 221 and 222.

The base member 210 may have a transparent or white color. When the base member 210 has a white color, a white pigment or the like may be included in the base member 210. When the base member 210 is white, light transmitted through the first resin layer 221 may be reflected. Then, the amount of light reflected by the solar cell 150 is increased, so that a larger amount of light can be reused in the solar cell 150. However, the present invention is not limited thereto, and the color of the base member 210 may be variously modified.

The first or second resin layers 221 and 222 may contain, as a base resin, various resins capable of improving various properties (eg, waterproofing, insulation, weather resistance, UV protection, etc.) of the rear sheet 200. I can. Here, the base resin may mean a resin included in 50 parts by weight or more with respect to the total 100 parts by weight of the first or second resin layers 221 and 222. Hereinafter, the first or second resin layers 221 and 222 are referred to as resin layers 221 and 222, and the description of the resin layers 221 and 222 below is a first resin layer 221 and a second resin layer. Each can be applied to (222).

For example, the resin layers 221 and 222 may include a fluorine-based resin such as polyvinly fluoride (PVF) or polyvinylidene fluoride (PVDF) as a base resin. Since fluorine-based resins do not have bonds that may be hydrolyzed, they are excellent in weather resistance and chemical resistance. In particular, polyvinylidene fluoride is _{a polymer having a structure of (CH 2} CF ₂ )n, and has a double fluorine molecule structure, so it has excellent mechanical properties, weather resistance, chemical resistance, and UV resistance. Alternatively, the resin layers 221 and 222 may include ethylene vinyl acetate copolymer resin (EVA), polyethylene (polyethylene, PE), or water-resistant polyethylene terephthalate as a base resin. Other various base resins may be used, and the present invention is not limited thereto.

The first resin layer 221 and the second resin layer 222 may be formed of the same material or different materials. In this case, materials for the first resin layer 221 and the second resin layer 222 may be selected and used according to desired characteristics.

For example, when the first and second resin layers 221 and 222 each contain a fluorine-based material, the weather resistance and reliability of the rear sheet 100 are improved by the excellent weather resistance and non-hydrolyzed properties of the fluorine-based material. You can improve. As another example, the first resin layer 221 adjacent to the solar cell 150 or the sealing material 130 includes an ethylene-vinyl acetate copolymer resin, polyethylene, etc. to reduce cost and improve adhesion to the second sealing material 132. In addition, the second resin layer 222 positioned on the outer surface may include a fluorine-based material or a water-resistant polyethylene terephthalate that does not easily undergo hydrolysis to improve the characteristics of the rear sheet 100.

In addition, the first or second resin layers 221 and 222 may further include an additive or the like in addition to the base resin described above. As an additive, various types of materials capable of supplementing or improving the characteristics of the first or second resin layers 221 and 222 may be used. For example, a sunscreen (eg, titanium oxide) may be included in the second resin layer 221 positioned adjacent to the outside of the solar cell module 100. In particular, when the second resin layer 221 contains water-resistant polyethylene terephthalate, a problem may occur due to ultraviolet rays, and thus a sunscreen agent may be included. In addition, various materials such as dispersants and pigments may be further included. The dispersant is added so that the base resin and other materials can be uniformly dispersed, and various known materials may be used. Pigments are added to adjust color to improve aesthetics or to adjust reflective properties, and various known materials may be used.

The thickness of the first or second resin layers 221 and 222 may be 10 μm to 200 μm. When the thickness of the first or second resin layers 221 and 222 is less than 10 μm, it may be difficult for the rear sheet 200 to have desired characteristics. When the thickness of the first or second resin layers 221 and 222 exceeds 200 μm, the thickness of the rear sheet 200 increases and may cause an increase in unit cost. However, the present invention is not limited to the thickness range of the first or second resin layers 221 and 222 described above, and may have various thicknesses. In addition, in the above description, only the case where both the first and second resin layers 221 and 222 are formed has been exemplified, but at least one of the first and second resin layers 221 and 222 may be omitted. Accordingly, as an example, the thickness of the second resin layer 222 may be 0 to 50 μm.

The first resin layer 221 may be thicker than the second resin layer 222. Then, by maximizing the effect of the first resin layer 221 in the portion adjacent to the sealing material 130, it is possible to effectively prevent the penetration of moisture, air, etc. into the sealing material 130. However, the present invention is not limited thereto, and the second resin layer 222 may have the same thickness as the first resin layer 221 or may have a thicker thickness. Other variations are possible.

A first adhesive layer 231 positioned between the first resin layer 221 and the base member 210 to bond them, and a second adhesive layer positioned between the second resin layer 222 and the base member 210 to bond them At least one of 232 may include a flame retardant material together with an adhesive material. In this embodiment, the first and second adhesive layers 231 and 232 each include an adhesive material and a flame-retardant material to maximize flame-retardant properties.

The adhesive material of the first or second adhesive layers 231 and 232 may include various materials having excellent adhesive properties while including a resin different from the base resin of the first and second resin layers 221 and 231. For example, a polyurethane-based or acrylic-based adhesive material having excellent adhesive properties and low material cost may be used. Various other adhesive materials can be used.

The flame retardant material of the first or second adhesive layers 231 and 232 may include various materials capable of improving flame retardancy. For example, a phosphorus-based flame retardant material may be used as the flame retardant material. The phosphorus-based flame-retardant material can exhibit great flame retardancy even with a relatively small amount of addition. In addition, since phosphorus-based flame-retardant materials do not contain metal, toxic gases that are harmful to the human body do not come out in case of fire. On the other hand, when a flame-retardant material containing bromine or a metal-based flame is ignited, toxic gases that are harmful to the human body may be released.

At this time, among various phosphorus-based flame-retardant materials, at least one of phosphate, phosphonate, phosphinate, phosphine oxide, phosphazene, and combinations thereof is first or It can be used as a flame retardant material for the second adhesive layers 231 and 232. Since these compounds are highly hydrophobic, filler-shaped compounds, they do not generate acids by hydrolysis and have high moist heat resistance. Accordingly, it is possible to prevent the first or second adhesive layers 231 and 232 from adhering the base member 210 and the first or second resin layers 221 and 222 to the base member 210 from deteriorating at a humid or high temperature.

More specifically, phosphorus-based flame retardant materials include tricresyl phosphate (TCP), trixylene phosphate (TXP), tributyl phosphate (TBP), triethyl phosphate (TEP), and Sildiphenyl phosphate (CDP), triphenyl phosphate (TPP), bisphenol A-bis (diphenyl phosphate) (bisphenol A-bis (dipheylphosphate), BDP), resorcinol bis (diphenyl phosphate) )(Resorcinol bis(diphenylphosphate), RDP), ammonium polyphosphate, melamine phosphate, trichloroisopropylphosphate (tri-(cloro isopropyl)phosphate, TCPP), dimethylphenylphosphonate phosphonate, DPP), dimethylaryl phosphonate, dimethylvinyl phosphonate, diethyl phosphinate ammonium salt, methylphosphonic acid, aluminum tri( Diethylphosphinate) (aluminium tis (diethylphosphinate)), aluminum hydroxymethylphenyl-phosphinate, and 9, 10 hydro-9-oxa-10-phosphaphenanthrene-10-oxide (9 ,10 dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, DOPO), and the like.

When these materials are included in the first or second adhesive layers 231 and 232 of the solar cell module 100, they do not deteriorate the adhesion properties with the base member 210 and the first and second resin layers 221 and 222. It is possible to improve the flame-retardant properties of the rear sheet 200 without.

A flame-retardant material may be included in the first adhesive layer 231 in an amount of 5 to 60 parts by weight based on 100 parts by weight of the first adhesive layer 231, and similarly, a flame-retardant material with respect to the total 100 parts by weight of the second adhesive layer 232 5 to 60 parts by weight may be included in the second adhesive layer 232. If the weight part of the flame retardant material is less than 5 parts by weight, the effect of improving the flame retardancy may be small, and if the weight part of the flame retardant material exceeds 60 parts by weight, the adhesive properties of the first or second adhesive layers 231 and 232 may be lowered. I can. However, the present invention is not limited thereto, and various modifications are possible.

The thickness of the first and/or second adhesive layers 231 and 232 may be smaller than that of the base member 210. This is because the first and/or second adhesive layers 231 and 232 need only have a thickness sufficient to have adhesive properties. For example, the thickness of the first and/or second adhesive layers 231 and 232 may be 3 μm to 30 μm. When the thickness of the first and/or second adhesive layers 231 and 232 is less than 3 μm, adhesive properties of the first and/or second adhesive layers 231 and 232 may be deteriorated. When the thickness of the first and/or second adhesive layers 231 and 232 exceeds 30 μm, the thickness of the rear sheet 200 may increase and material cost may increase. However, the present invention is not limited thereto, and various modifications are possible.

In addition, the thickness of the first and/or second adhesive layers 231 and 232 may be smaller than that of the first or second resin layers 221 and 222. This is because the first or second adhesive layers 231 and 232 need only have a thickness sufficient to have adhesive properties. However, as described above, since the first and second resin layers 221 and 222 may have various thicknesses, the present invention is not limited thereto. Accordingly, the thickness of the first and/or second adhesive layers 231 and 232 may be equal to or greater than the first or second resin layers 221 and 222.

In the present embodiment, the first adhesive layer 231 and the second adhesive layer 232 may have the same composition and thus have the same characteristics. Then, by forming the first adhesive layer 231 and the second adhesive layer 232 using a mixture of the same adhesive material and flame retardant material, it is possible to simplify the process and reduce the material cost. In addition, the first adhesive layer 231 and the second adhesive layer 232 may have substantially the same thickness (for example, the thickness difference is within 10%) so that the same equipment, process conditions, and the like may be used. Then, the process can be further simplified and the material cost can be further reduced.

However, the present invention is not limited thereto, and the composition and characteristics of the first adhesive layer 231 and the second adhesive layer 232 may be different from each other.

In addition, in the present embodiment, both of the first and second adhesive layers 231 and 232 include an adhesive material and a flame retardant material to further improve flame retardancy. However, the present invention is not limited thereto, and a flame retardant material may be included in only at least one of the first and second adhesive layers 231 and 232. For example, the first adhesive layer 231 may include an adhesive material and a flame retardant material, and the second adhesive layer 232 may include an adhesive material but not a flame retardant material. Then, the probability that the first adhesive layer 231 that adheres the first resin layer 221 adjacent to the solar cell 150 or the sealing material 130 includes a flame-retardant material to reach external ultraviolet rays or the like may be lowered. Accordingly, it is possible to prevent decomposition of the flame retardant material from occurring in the first adhesive layer 231 due to ultraviolet rays or the like. As another example, the second adhesive layer 232 may include an adhesive material and a flame retardant material, and the first adhesive layer 231 may include an adhesive material but not a flame retardant material. Then, it is possible to more effectively prevent the fire generated from the outside of the solar cell module 100 from being transferred to the inside of the solar cell module 100. Other variations are possible.

The above-described first and/or second adhesive layers 231 and 232 may be manufactured by various methods and used for manufacturing the rear sheet 200 by various methods.

For example, in order to form the first and/or second adhesive layers 231 and 232, an adhesive mixture in which an adhesive material, a flame retardant material, and other additives are mixed may be prepared. Various known methods can be used as the mixing method.

Lamination in which heat and pressure are applied while the adhesive mixture thus prepared is applied to one surface of the base member 210 to form the first adhesive layer 231, and the first resin layer 221 in the form of a film or sheet is positioned thereon. Through the process, the base member 210 and the first resin layer 221 are adhered by the first adhesive layer 231. Various known methods can be used as a method of applying the adhesive mixture. For example, if a printing method is used, the first adhesive layer 231 can be evenly applied on one surface of the base member 210, thereby providing more adhesive properties. You can improve.

And lamination in which heat and pressure are applied while the prepared adhesive mixture is applied to the other surface of the base member 210 to form the second adhesive layer 232, and the second resin layer 222 in the form of a film or sheet is placed thereon. Through the process, the base member 210 and the second resin layer 222 are adhered by the second adhesive layer 232. Various known methods may be used as a method of applying the adhesive mixture. For example, when a printing method is used, the second adhesive layer 232 can be evenly applied on the other surface of the base member 210, thereby further enhancing the adhesive properties. You can improve.

Accordingly, the first resin layer 221, the first adhesive layer 231, the base member 210, the second adhesive layer 232 and the second resin layer 222 are bonded and bonded to each other to form an integral structure of the rear sheet ( 200). At this time, the first resin layer 221, the first adhesive layer 231, the base member 210, the second adhesive layer 232 and the second resin layer 222 are formed in contact with each other to form the structure of the rear sheet 200. It can be simplified. However, the present invention is not limited thereto, and various modifications are possible, such as a separate layer positioned between the two layers.

In the above description, after attaching the first resin layer 221 to the base member 210 using the first adhesive layer 231, the second resin layer 222 is attached to the base member using the second adhesive layer 232 ( 220) was illustrated. However, the present invention is not limited to this order. Therefore, after bonding the second resin layer 222 to the base member 210 using the second adhesive layer 232, the first resin layer 221 is attached to the base member 220 using the first adhesive layer 231. It is also possible to adhere to.

In this embodiment, the process of bonding the first resin layer 221 to one surface of the base member 210 using the first adhesive layer 231 and the other surface of the base member 210 using the second adhesive layer 232 By separately performing a process of bonding the second resin layer 222 to each other, adhesion properties of the first and second resin layers 221 and 222 may be improved. However, the present invention is not limited thereto, and after forming both the first and second adhesive layers 231 and 232 on both sides of the base member 210, the first and second resin layers 221 and 222 are positioned to heat and It is also possible to bond them all at once by applying pressure. Then, the manufacturing process of the rear sheet 200 can be simplified. Other variations are possible.

In this embodiment, not the base member 210 and the first and second resin layers 221 and 222, but the first and second adhesive layers 231 and 232 for bonding them include a flame retardant material. That is, the base member 210 and the first and second resin layers 221 and 222 do not contain an adhesive material and a flame retardant material, and the first and second adhesive layers 231 and 232 contain an adhesive material and a flame retardant material. do. Accordingly, it is possible to prevent the properties of the first and second resin layers 221 and 222 from deteriorating. For example, if a flame-retardant material is included in the first resin layer 221 adjacent to the sealing material 130, the adhesion to the second sealing material 132 may be reduced, thereby reducing the reliability of the solar cell module 100. have. When a flame-retardant material is included in the second resin layer 222 positioned toward the outside, the flame-retardant material is decomposed by ultraviolet rays from the outside, thereby reducing the effect of the flame-retardant material and the reliability of the solar cell module 100.

In addition, the flame-retardant material may be easily placed in the rear sheet 200 by mixing a flame-retardant material with the first and second adhesive layers 231 and 232 that are manufactured in an adhesive mixture and applied on the base member 210. Thereby, the base member 210 supplied in the form of a film or sheet, and the first and second resin layers 221 and 222 can sufficiently play their original roles, while a rear sheet having high flame retardancy by a simple method. (200) can be implemented. On the other hand, since the base member 210 and the first and second resin layers 221 and 222 are supplied in the form of a film or a sheet, it is difficult to change the composition, and the inclusion of a flame-retardant material in them makes the process complicated.

In the drawings and the above description, a first adhesive layer 231 positioned between the base member 210 and the first resin layer 221 and a second adhesive layer positioned between the base member 220 and the second resin layer 222 It is illustrated that at least one of (232) includes a flame retardant material together with an adhesive material. However, the present invention is not limited thereto, and when the rear sheet 210 includes a plurality of layers, it is sufficient if at least one of the plurality of adhesive layers for bonding them between the plurality of layers includes a flame retardant material together with the adhesive material.

Features, structures, effects, and the like according to the above are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

100: solar cell module
110: front board
131: first sealing material
132: second sealing material
150: solar cell
200: rear sheet
210: base member
221: first resin layer
222: second resin layer
231: first adhesive layer
232: second adhesive layer

Claims (18)

At least one solar cell;
A sealing material surrounding and sealing the solar cell; And
A rear sheet located on the rear side of the solar cell on the sealing material
Including,
The rear sheet,
Base member;
A first resin layer positioned between one surface of the base member and the sealing material;
A first adhesive layer that bonds them between the base member and the first resin layer and includes an adhesive material and a flame retardant material;
A second resin layer positioned on the other surface of the base member; And
A second adhesive layer positioned between the base member and the second resin layer and comprising the adhesive material and the flame retardant material
Including,
The first resin layer and the second resin layer have a thickness of 10 to 200 um, the first resin layer is formed thicker than the second resin layer,
The first adhesive layer and the second adhesive layer contain 5 to 60 parts by weight of the flame retardant material based on a total of 100 parts by weight,
The thickness of the first adhesive layer and the second adhesive layer is 3um to 30um,
The thickness of the first adhesive layer is smaller than that of the base member or the first resin layer, and the thickness of the second adhesive layer is smaller than that of the base member or the second resin layer. The method of claim 1,
The flame retardant material is a solar cell module comprising a phosphorus flame retardant material. The method of claim 2,
The flame retardant material is a solar cell module comprising at least one of phosphate, phosphonate, phosphinate, phosphine oxide and phosphazene, and combinations thereof. The method of claim 3,
The phosphorus-based flame retardant material is tricresyl phosphate (TCP), trixylene phosphate (TXP), tributyl phosphate (TBP), triethyl phosphate (TEP), cresyldiphenyl ㅍ Phosphate (cresyldiphenyl phosphate, CDP), triphenyl phosphate (TPP), bisphenol A-bis (diphenyl phosphate) (bisphenol A-bis (dipheylphosphate), BDP), resorcinol bis (diphenyl phosphate) (Resorcinol bis(diphenylphosphate), RDP), ammonium polyphosphate, melamine phosphate, tri-(cloro isopropyl)phosphate, TCPP), dimethylphenyl phosphonate (DPP) ), dimethylaryl phosphonate, dimethylvinyl phosphonate, diethyl phosphinate ammonium salt, methylphosphonic acid, aluminum tri(diethylphosphonate) Pinate) (aluminium tis (diethylphosphinate)), aluminum hydroxymethylphenyl-phosphinate, 9, 10 hydro-9-oxa-10-phosphaphenanthrene-10-oxide (9,10 dihydro- 9-oxa-10-phosphaphenanthrene-10-oxide, DOPO), and a solar cell module comprising at least one of a combination thereof. The method of claim 1,
The solar cell module wherein the adhesive material includes a polyurethane-based material or an acrylic material. delete delete delete delete delete delete delete delete delete delete delete delete delete

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