阅读说明：本技术 太阳能电池前板膜及其制作方法、太阳能电池 (Solar cell front plate film, manufacturing method thereof and solar cell ) 是由 白安琪 徐强 郭会永 于 2018-07-25 设计创作，主要内容包括：本发明公开了一种太阳能电池前板膜,包括依次设置的表层、粘接层、阻挡层和底层；所述底层朝向所述阻挡层的一面具有纳米结构阵列；在沿所述阻挡层到所述底层的方向上,所述纳米结构阵列中的纳米结构的截面积逐渐变化。本发明提出的太阳能电池前板膜及其制作方法、太阳能电池,能在一定程度上提高光透过性。(The invention discloses a solar cell front plate film, which comprises a surface layer, an adhesive layer, a barrier layer and a bottom layer which are sequentially arranged; the side, facing the barrier layer, of the bottom layer is provided with a nanostructure array; the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction from the barrier layer to the bottom layer. The solar cell front plate film, the manufacturing method thereof and the solar cell can improve the light transmission property to a certain extent.)

1. The solar cell front plate film is characterized by comprising a surface layer (14), an adhesive layer (13), a barrier layer (12) and a bottom layer (11) which are sequentially arranged; the surface of the bottom layer (11) facing the barrier layer (12) is provided with a nanostructure array; the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction along the barrier layer (12) to the bottom layer (11).

2. Solar cell front sheet film according to claim 1, wherein the bottom layer (11) has projections and/or recesses on its surface facing the barrier layer (12), said projections and/or recesses forming said nanostructures.

3. The solar cell front sheet film of claim 2, wherein the shape of the nanostructures is pyramidal, truncated pyramidal, partially spherical, or partially ellipsoidal.

4. The solar cell front sheet film according to claim 3, wherein the cone is a cone or pyramid and/or the frustum is a truncated cone or frustum of a pyramid.

5. The solar cell front sheet film according to claim 2, wherein when the nanostructure comprises a protrusion, the height of the protrusion is 30 to 50 nm; or when the nano structure comprises a concave part, the depth of the concave part is 30-50 nm.

6. The solar cell front sheet film of claim 1, wherein the nanostructures have a pitch of 80 to 120 nm.

7. The solar cell front sheet film according to claim 1, wherein the barrier layer (12) has a thickness of 30 to 100 nm.

8. Solar cell front sheet film according to claim 1, wherein the refractive index of the barrier layer (12) is larger than the refractive index of the bottom layer (11).

9. The solar cell front sheet film according to claim 1, wherein the bottom layer (11) is made of polyethylene terephthalate or polyethylene naphthalate, the barrier layer (12) is made of alumina, titanium oxide or titanium nitride, the adhesive layer (13) is made of an ethylene-vinyl acetate copolymer, a thermoplastic polyolefin or an ethylene-octene copolymer, and the surface layer (14) is made of an ethylene-tetrafluoroethylene copolymer.

10. A solar cell comprising the solar cell front sheet film according to any one of claims 1 to 9.

11. A method for manufacturing a solar cell front plate film is characterized by comprising the following steps:

forming a nanostructure array on a substrate (11') to obtain a bottom layer (11) of the solar cell front plate film;

forming a barrier layer (12) on the side of the bottom layer (11) on which the nanostructure array is formed;

sequentially laying an adhesive layer (13) and a surface layer (14) on the barrier layer (12);

laminating to form the solar cell front sheet film;

wherein the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction along the barrier layer (12) to the bottom layer (11).

12. The method according to claim 11, wherein forming the nanostructure array on a substrate (11') resulting in a bottom layer (11) of a solar cell front sheet film comprises:

obtaining a template (40) having an array of nanopatterns, the pattern of the array of nanopatterns being opposite to the pattern of the array of nanostructures;

heating the substrate (11');

contacting said template (40) with said substrate (11 '), and pressurizing said substrate (11') to fill said nanopattern array of said template (40);

cooling to solidify and shape the base material (11');

and taking out the template (40) to obtain the bottom layer (11) of the solar cell front panel film.

Technical Field

The invention relates to the technical field of solar energy, in particular to a solar cell front plate film, a manufacturing method thereof and a solar cell.

Background

The flexible thin film solar cell refers to a thin film solar cell which takes flexible materials such as stainless steel, polymers and the like as substrate materials. The flexible thin-film solar cell has the characteristics of light weight, thin thickness, flexibility and the like, can be widely applied to portable equipment and mobile energy, can be directly adhered to the surface of an object, and can be applied to building roofs, wall surfaces and the like.

The flexible thin-film solar cell module can be divided into three parts from top to bottom, namely a cell front plate film, a cell functional layer and a cell back plate. The battery pack is generally used in an outdoor environment and is subjected to tests such as wind, sunlight, rain, dust, abrasion, and the like, and thus the performance of a front sheet film, i.e., a light-receiving surface thereof is required to be high, and high light transmittance, water resistance, UV resistance, and certain mechanical strength are required. The surface layer of the current commonly used front panel film mainly has the functions of reinforcement, weather resistance, UV resistance, moisture resistance, low dielectric constant, high breakdown voltage and the like; the bottom layer of the front panel film with the barrier layer mainly plays a role in water resistance and oxygen isolation, wherein the barrier layer is usually an inorganic coating, and the thickness of the barrier layer is usually 10-500 nm; the surface layer and the bottom layer are adhered by pressure-sensitive adhesive.

The front plate film of the flexible thin film battery is a barrier before sunlight enters a battery functional layer, so that the front plate film is required to have higher light transmittance so as to reduce light loss as much as possible and improve light utilization efficiency, and the light transmittance of the front plate film in the current mainstream market is about 90% at most. However, in order to realize multiple functions of water resistance, weather resistance, UV resistance, breakdown resistance, mechanical damage resistance and the like, the front panel film needs to adopt a composite multilayer film structure, and needs to have a certain thickness to realize the functions of water resistance and oxygen insulation, but an excessively thick barrier layer can generate large loss on light transmittance; not only is there light absorption in each layer of film itself, but also light reflection caused by the difference in material refractive index between the interfaces of the multilayer film becomes the main light loss mechanism, and great examination is made on the overall light transmittance.

Disclosure of Invention

In view of the above, an object of the embodiments of the present invention is to provide a front sheet film for a solar cell, a method for manufacturing the same, and a solar cell, which can improve light transmittance to some extent.

In view of the above object, a first aspect of embodiments of the present invention provides a solar cell front sheet film, including a surface layer, an adhesive layer, a barrier layer, and a bottom layer, which are sequentially disposed; the side, facing the barrier layer, of the bottom layer is provided with a nanostructure array; the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction from the barrier layer to the bottom layer.

Optionally, the surface of the bottom layer facing the barrier layer has protrusions and/or recesses, and the protrusions and/or recesses form the nanostructures.

Optionally, the shape of the nanostructure is a cone, a frustum, a partial sphere, or a partial ellipsoid.

Optionally, the cone body is a cone or a pyramid, and/or the frustum is a truncated cone or a truncated pyramid.

Optionally, when the nanostructure comprises a protrusion, the height of the protrusion is 30-50 nm; or when the nano structure comprises a concave part, the depth of the concave part is 30-50 nm.

Optionally, the distance between the nano structures is 80-120 nm.

Optionally, the thickness of the barrier layer is 30-100 nm.

Optionally, the refractive index of the barrier layer is greater than the refractive index of the bottom layer.

Optionally, the bottom layer is made of polyethylene terephthalate or polyethylene naphthalate, the barrier layer is made of aluminum oxide, titanium oxide or titanium nitride, the bonding layer is made of an ethylene-vinyl acetate copolymer, thermoplastic polyolefin or ethylene-octene copolymer, and the surface layer is made of an ethylene-tetrafluoroethylene copolymer.

In a second aspect of embodiments of the present invention, there is provided a solar cell comprising a solar cell front sheet film as described in any one of the preceding claims.

In a third aspect of the embodiments of the present invention, there is provided a method for manufacturing a front plate film of a solar cell, including:

forming a nanostructure array on a substrate to obtain a bottom layer of a solar cell front panel film;

forming a barrier layer on one surface of the bottom layer on which the nanostructure array is formed;

sequentially laying an adhesive layer and a surface layer on the barrier layer;

laminating to form the solar cell front sheet film;

wherein the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction from the barrier layer to the bottom layer.

Optionally, forming a nanostructure array on a substrate to obtain a bottom layer of a solar cell front sheet film, comprises:

obtaining a template with a nano-pattern array, wherein the pattern of the nano-pattern array is opposite to that of the nano-structure array;

heating the substrate;

contacting the template with the substrate, and pressurizing to fill the substrate with the nano-pattern array of the template;

cooling to solidify and shape the base material;

and taking out the template to obtain the bottom layer of the solar cell front panel film.

As can be seen from the above, according to the solar cell front plate film, the manufacturing method thereof, and the solar cell provided in the embodiments of the present invention, the three-dimensional nanostructure array layer is prepared on the surface of the bottom layer by using the nano preparation technology, and then the barrier layer is prepared on the surface of the nanostructure, so that the barrier layer is embedded into the nanostructure on the surface of the bottom layer, and the bottom layer/barrier layer transition layer is formed between the bottom layer and the barrier layer.

Drawings

Fig. 1 is a schematic structural diagram of a solar cell front sheet film according to an embodiment of the present invention;

FIG. 2a is a schematic diagram showing the variation of the ratio of the bottom layer to the barrier layer along the thickness direction of the nanostructure array according to the embodiment of the present invention;

FIG. 2b is a schematic diagram showing the variation of the refractive index of the barrier layer, the nanostructure array layer, and the bottom layer along the thickness direction according to the embodiment of the present invention;

fig. 3 is a schematic structural diagram of a solar cell according to an embodiment of the present invention;

fig. 4 is a schematic flow chart of a method for manufacturing a front sheet film of a solar cell according to an embodiment of the present invention;

FIG. 5a is a schematic diagram of a state in preparation for forming a nanostructure array on a substrate using a template according to an embodiment of the present invention;

FIG. 5b is a schematic view of the template pressed into the substrate according to the embodiment of the present invention;

FIG. 5c is a schematic view of the bottom layer formed after the template is removed in an embodiment of the present invention;

FIG. 5d is a schematic view of an embodiment of the present invention after forming a barrier layer on the underlayer;

FIG. 5e is a schematic illustration of an embodiment of the invention in preparation for laying up a skin layer and an adhesive layer;

FIG. 5f is a schematic illustration of a solar cell front sheet film laminated in accordance with an embodiment of the present invention;

fig. 6 is a schematic flow chart illustrating the formation of the bottom layer of the solar cell front sheet film in the method for manufacturing the solar cell front sheet film according to the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are used for distinguishing two entities with the same name but different names or different parameters, and it should be noted that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and they are not described in any more detail in the following embodiments.

In a first aspect of embodiments of the present invention, there is provided a solar cell front sheet film capable of improving light transmittance to some extent. Fig. 1 is a schematic structural diagram of a solar cell front sheet film according to an embodiment of the present invention.

The solar cell front plate film comprises a surface layer 14, an adhesive layer 13, a barrier layer 12 and a bottom layer 11 which are sequentially arranged; the side of the bottom layer 11 facing the barrier layer 12 is provided with a nanostructure array; the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction along the barrier layer 12 to the bottom layer 11. For example, the cross-sectional area of the nanostructures gradually decreases or the cross-sectional area of the nanostructures gradually increases in the direction from the barrier layer 12 to the bottom layer 11.

Optionally, the surface of the bottom layer 11 facing the barrier layer 12 has a protrusion or a recess, or both a protrusion and a recess are formed; the projections and/or depressions form the nanostructures. Wherein the protrusion may take the form of a nanodot, and the recess may take the form of a nanopore.

Optionally, when the nanostructure array comprises the recess, the cross-sectional area of the recess gradually decreases in a direction from the barrier layer 12 to the bottom layer 11; when the nanostructure array includes projections, the cross-sectional area of the projections gradually increases in a direction along the barrier layer 12 to the underlayer 11. It should be noted that the structure of the solar cell front sheet film is illustrated in fig. 1 by the case where the nanostructure array is formed by the concave portions, but it can be understood that the effect is substantially uniform when the nanostructure array is designed to be formed by the convex portions or the convex portions and the concave portions.

The following detailed analysis utilizes the principle of nanostructures to reduce light reflection at material interfaces.

Assuming that the refractive index of the underlying material is n₁1.65, the refractive index of the barrier material is n₂With conventional front sheet films, the difference in refractive index between the two results in an abrupt change in refractive index at the interface of the underlayer and the barrier layer, resulting in reflection loss of light.

FIG. 2a is a schematic diagram illustrating the variation of the ratio of the bottom layer to the barrier layer along the thickness direction of the nanostructure array according to the embodiment of the present invention; fig. 2b is a schematic diagram showing the variation of the refractive index of the barrier layer, the nanostructure array layer, and the bottom layer in the thickness direction according to the embodiment of the present invention.

When the surface of the bottom layer 11 has a nanopore array structure, assuming that the bottom layer is a structure formed by stacking an infinite number of planes from bottom to top, and the material ratio of the bottom layer material to the barrier layer material in a plane with a certain thickness d is defined as the ratio of the area occupied by the materials to the total area, then the ratio f of the bottom layer material from the bottom to the top of the nanopore₁The distribution rule of the nano-pores is related to the shapes of the nano-pores along with the increase of the sectional areas of the nano-pores, and the ratio of the area below the bottom of the nano-pores to the area above the top of the nano-pores is 1 and 0 respectively. After deposition of the barrier layer in the array of holes, the ratio distribution of the barrier layer material to the underlying material is related by f₂＝1-f₁As shown in fig. 2 a.

Since the nanostructure array layer is a non-uniform material, its refractive index is defined by the refractive indices n of the two materials₁、n₂And the ratio f of the two materials₁、f₂The determination can be made by the equivalent refractive index n_effIs shown as n_effVariation in thickness direction and f₁And f₂Distribution of (D) has a relation of n_eff＝f(f₁,f₂) And n is_eff(f₁＝1)＝n₁，n_eff(f₁＝0)＝n₂. FIG. 2(b) shows a graded structure n_effExamples of (2). It can be seen that the refractive index at the interface with the conventional underlayer and barrier layerIn the embodiment of the invention, a nanopore layer with equivalent refractive index n exists between the bottom layer and the barrier layer_effAt n₁And n₂The gradual change is generated between the front plate film and the front plate film, so that the light reflection is greatly reduced compared with the refractive index mutant type interface, and the integral light transmission of the front plate film is increased.

As can be seen from the foregoing embodiments, in the solar cell front plate film provided in the embodiments of the present invention, a three-dimensional nanostructure array layer is prepared on the surface of a bottom layer by using a nano preparation technology, and then a barrier layer is prepared on the surface of the nanostructure array layer, so that the barrier layer is embedded into the nanostructure on the surface of the bottom layer, and a bottom layer/barrier layer transition layer is formed between the bottom layer and the barrier layer.

As an embodiment of the present invention, the shape of the nanostructure in the nanostructure array is a cone, a frustum, a partial sphere or a partial ellipsoid.

As an embodiment of the present invention, the cone is a cone or a pyramid, and/or the frustum is a truncated cone or a truncated pyramid.

As an embodiment of the present invention, the refractive index of the barrier layer 12 is greater than the refractive index of the bottom layer 11 to achieve a graded refractive index of the transition layer therebetween.

As an embodiment of the present invention, the thickness of the barrier layer 12 is required to cover the nanostructure array.

According to one embodiment of the invention, the depth of the concave parts in the nanostructure array is 30-50nm, the distance between the concave parts is 80-120nm, and the thickness of the barrier layer 12 is 30-100 nm. Optionally, when the recessed portion is a cone or a frustum of a cone, the diameter of the recessed portion is 30-60 nm.

As an embodiment of the invention, the height of the convex parts in the nanostructure array is 30-50nm, the distance between the convex parts is 80-120nm, and the thickness of the barrier layer 12 is 30-100nm, so that a good light transmission effect is realized. Optionally, when the protrusion is a cone or a frustum of a cone, the diameter of the protrusion is 30-60 nm.

The best light transmission effect can also be achieved by further optimizing the shape, height, spacing and period of the nanostructures.

In one embodiment of the present invention, the bottom layer 11 is made of resin, the barrier layer 12 is made of inorganic material, the adhesive layer 13 is made of pressure-sensitive adhesive, and the surface layer 14 is made of fluoropolymer.

Alternatively, the barrier layer 12 may be replaced by other materials, such as inorganic composite materials, organic-inorganic composite materials, and the like.

As an embodiment of the present invention, the bottom layer 11 is made of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), and the barrier layer 12 is made of alumina (Al)₂O₃) Titanium oxide (TiO)₂) Or titanium nitride (TiN), the adhesive layer 13 is made of ethylene-vinyl acetate copolymer (EVA), Thermoplastic Polyolefin (TPO) or ethylene-octene copolymer (DNP), and the surface layer 14 is made of ethylene-tetrafluoroethylene copolymer (ETFE), so as to achieve a good light transmission effect.

In a second aspect of the embodiments of the present invention, there is provided a solar cell capable of improving light transmittance to some extent. Fig. 2 is a schematic structural diagram of a solar cell according to an embodiment of the present invention. The solar cell comprises any embodiment of the solar cell front sheet film and any combination of embodiments thereof.

As can be seen from the foregoing embodiments, in the solar cell provided in the embodiments of the present invention, a three-dimensional nanostructure array layer is prepared on the bottom surface of the front sheet film by using a nano preparation technique, and then a barrier layer is prepared on the surface of the nanostructure array layer, so that the barrier layer is embedded into the nanostructure on the bottom surface, and a bottom layer/barrier layer transition layer is formed between the bottom layer and the barrier layer.

As an embodiment of the present invention, the solar cell can be divided into three major parts from top to bottom, as shown in fig. 3, which are a solar cell front sheet film 10, a solar cell functional layer 20 (including a solar module 21 and an Edge Seal (Edge Seal)22), and a solar cell back sheet 30. Wherein, the surface layer 14 of the solar cell front panel film 10 is a transparent fluorine-containing polymer, and mainly has the functions of reinforcement, weather resistance, UV resistance, moisture resistance, low dielectric constant, high breakdown voltage and the like; the bottom layer 11 of the solar cell front panel film 10 is made of resin such as PET or PEN with a barrier layer 12 on the surface, and mainly used for water resistance and oxygen isolation; the surface layer 14 and the bottom layer 13 are adhered by an adhesive layer 13, and the barrier layer 12 is usually an inorganic coating, and the inorganic material may be Al₂O₃、TiN、TiO₂And the thickness can be 10 to 500 nm. In addition, a Black Tape (Black Tape)15 for light shielding is further provided at the edge of the solar cell front sheet film 10.

In a third aspect of the embodiments of the present invention, a method for manufacturing a front sheet film of a solar cell is provided, which can improve light transmittance to some extent. Fig. 4 is a schematic flow chart of a method for manufacturing a front sheet film of a solar cell according to an embodiment of the present invention.

The manufacturing method of the solar cell front plate film comprises the following steps:

step 501: forming a nanostructure array on the substrate 11' resulting in the bottom layer 11 of the solar cell front sheet film (as shown in fig. 5 c);

optionally, the substrate 11' may also be pretreated, e.g., cleaned, prior to formation of the nanostructure array; the substrate 11' can be selected from a PET material, and the cleaning can be performed by plasma (plasma); alternatively, the nanostructure array formed on the substrate 11' may be formed by a hot stamping method; the size of the nano-pores can be 30-50nm in depth, 30-60nm in pore diameter and 80-120nm in pore spacing.

Step 502: forming a barrier layer 12 on the side of the bottom layer 11 on which the nanostructure array is formed (as shown in fig. 5 d);

optionally, a layer of Al is deposited on the surface of the bottom layer 11 by an ALD (Atomic layer deposition) process₂O₃Depositing a layer at 50-150 deg.C under 10 mTorr-100 Torr to a thickness of 30-100nm, wherein the thickness of the layer is greater than the depth of the nano-pores to make Al₂O₃The layer completely covers the nanopore.

Step 503: an adhesive layer 13 and a surface layer 14 are sequentially laid on the barrier layer 12 (as shown in fig. 5 e).

Step 504: laminating the surface layer 14, the adhesive layer 13, the barrier layer 12 and the bottom layer 11 to form the solar cell front panel film (as shown in fig. 5 f);

wherein the cross-sectional area of the nanostructures in the nanostructure array gradually changes in a direction from the barrier layer 12 to the bottom layer 11.

As can be seen from the foregoing embodiments, in the method for manufacturing a solar cell front plate film according to the embodiments of the present invention, a three-dimensional nanostructure array is prepared on the surface of a bottom layer by using a nano preparation technology, and then a barrier layer is prepared on the surface of the nanostructure, so that the barrier layer is embedded into the nanostructure on the surface of PET, and the barrier layer covers the nanostructure array, thereby forming a transition layer between the bottom layer and the barrier layer, and then the transition layer is laminated with an adhesive layer and a surface layer, so as to obtain a solar cell front plate; compared with the conventional planar interface between the bottom layer and the barrier layer, the transition layer in the solar cell front plate utilizes the gradual change of the material proportion to form the gradual change refractive index, so that the light reflection caused by the abrupt change of the material refractive index is reduced, and the light transmittance of the front plate film is improved.

As an embodiment of the present invention, as shown in fig. 6, a nanostructure array is formed on a substrate 11' to obtain a bottom layer 11 of a solar cell front sheet film, which specifically includes:

step 601: obtaining a template 40 having an array of nanopatterns, which is opposite to the pattern of the array of nanostructures (as shown in fig. 5 a);

step 602: heating the substrate 11'; optionally, the substrate 11' may be placed in a heating device and heated to 100-;

step 603: contacting the template 40 with the substrate 11 ', and pressurizing to fill the substrate 11' with the nanopattern array of the template 40 (as shown in FIG. 5 b);

step 604: cooling (e.g., to below 80 ℃) to solidify and shape the substrate 11';

step 605: the template 40 is taken out to obtain the bottom layer 11 of the solar cell front sheet film (as shown in fig. 5 c).

By the method, the corresponding nano-structure array is obtained, and the effect of the transition layer is realized.

Those of ordinary skill in the art will understand that: the invention is not to be considered as limited to the specific embodiments thereof, but is to be understood as being modified in all respects, all changes and equivalents that come within the spirit and scope of the invention.