WO2015139516A1

WO2015139516A1 - Solar cell encapsulant structure and method for manufacturing same

Info

Publication number: WO2015139516A1
Application number: PCT/CN2015/000176
Authority: WO
Inventors: 仇桂芬
Original assignee: 仇桂芬
Priority date: 2014-03-20
Filing date: 2015-03-17
Publication date: 2015-09-24
Also published as: CN103865420A; CN103865420B

Abstract

The present invention relates to a solar cell encapsulant structure and a method for manufacturing the same. The solar cell encapsulant structure comprises an encapsulant layer and at least one layer of functional film, or comprises an encapsulant layer, at least one layer of functional film, and at least one transition layer close next to the functional film. The functional film is combined with the encapsulant layer, or the functional film is combined with the encapsulant layer and the transition layer. The fluidity of the functional film is less than that of the encapsulant layer. In the present invention, a layer of functional film having relatively low fluidity is combined with an encapsulant film; because the fluidity of the functional film is lower than that of the encapsulant film, it is more difficult for the functional film to overflow than it is for an encapsulant, and there is a very desirable effect of inhibiting an encapsulant having relatively high fluidity from overflowing.

Description

Solar cell chip encapsulation structure and preparation method thereof

Technical field

The invention relates to a film, in particular to a solar cell encapsulant and a preparation method thereof.

Background technique

Since the solar cell back encapsulant does not require high light transmission performance, it can be used with a film having a low transmittance, or a certain filler can be added to increase the function and reduce the cost. If the glue with lower transmittance is used, the cost is reduced, the back plate is protected, and the damage of the ultraviolet rays to the back plate is reduced; the filler with high reflectivity is added to increase the reflectance, thereby reflecting the sunlight, being reabsorbed by the battery, and improving the solar energy. Battery power; adding thermal conductive filler to improve the thermal conductivity of the back encapsulant, reducing the effect of temperature on battery efficiency, and so on. In addition, in order to make the battery sheet absorb the energy of the ultraviolet radiation in the ultraviolet band, the surface-encapsulating adhesive avoids the addition of the ultraviolet absorber, so that the ultraviolet light can reach the surface of the battery sheet, and the ultraviolet absorber is added to the backlight surface encapsulant to protect the back sheet. Avoid UV damage. In this structure, the ultraviolet absorber affects the enveloping surface encapsulant during the aging process, so that the ultraviolet portion cannot reach the surface of the cell sheet and loses a certain conversion rate. Adding a light-shielding filler to the back surface encapsulant can well protect the backsheet and maintain conversion efficiency and reduce attenuation. However, such a back encapsulant will be fused with the encapsulating adhesive having a high transparency on the mating surface during the lamination process, and wrinkles and textures are easily formed at the junction, and it is easy to overflow the surface of the cell or the strip to block the sunlight. And seriously affect the appearance of the component. At present, the encapsulant is basically EVA or polyolefin.

The development of solar cells to the present, 1% or even less power generation is a major technological advancement. Not only the solar cell itself, but also the packaging material as an important part of the solar module, its contribution to power needs to be further explored. The functions and requirements of the mating surface and the back surface encapsulant in the solar cell are different, and further refinement can bring other advantages such as power gain or cost reduction, and has high development value.

The prior art generally has the following three schemes:

1. A layer of transparent encapsulant is combined with a low transmittance encapsulant. This method is isolated with a layer of transparent glue that blocks the white encapsulant from contaminating the cell. However, this method has not studied the root cause of overflow or texture. A similar patent, such as application number 201220587305.3, double-glass photovoltaic module, adds a transparent encapsulant between the cell sheet and the white back encapsulant, without the encapsulant. The flow characteristics and process methods are described and studied in depth. Similar products, such as the transparent-white double-layer EVA currently on the market, need to face the transparent layer when facing the battery. In fact, it is necessary to avoid the stained backlight encapsulant overflowing the contaminated cell. The backlight encapsulation on the cell is not necessarily transparent. It can be made into white or other colors with low transparency without any overflow. Or the appearance of the texture. Moreover, the transparent encapsulating adhesive with strong fluidity has a limited barrier effect, so this method is not ideal for the control of overflow. In addition, these methods of adding a transparent layer between the battery sheet and the back white encapsulant, the effect of reflecting sunlight is slightly inferior, because the transparent layer itself has a certain suction on the sunlight. It will increase the optical path of the reflected light and weaken the effect of increasing power. This patent proves by experiment that there is no need to add a transparent film between the battery sheet and the back encapsulant to prevent the white or other color back encapsulant from overflowing with poor transparency, as long as the battery is in accordance with the method described in this patent. The sheet can also be directly in contact with the less transparent backside encapsulant film, or the thickness of the transparent layer between the cell sheet and the back encapsulant can be greatly reduced, thereby allowing more direct reflection of sunlight or conduction of heat or other effects, and the entire The bonding effect and crosslinking degree of the system are not affected much.

2, the use of glass fiber and back encapsulation compound. This is already an authorized patent. (Application No. 201220121792.4, a white EVA and fiberglass cloth composite solar cell encapsulation film) However, glass fiber has certain risks, damage to the respiratory system and skin, and many people are allergic to fiberglass. This method will bring certain safety hazards, and the glass fiber used in this method needs special processing and the cost is relatively high.

3. It is made of non-woven fabric and back encapsulant. This is already an authorized patent (application number 201220724624.4, publication number CN203013768 U high-reflection EVA film for photovoltaic modules). This method can also avoid overflow very well, but the disadvantage is that, on the one hand, the non-woven fabric is processed into a fibrous material and then processed, and the cost is high; in addition, one additional surface is added to the surface of the non-woven fabric. The layer transparent EVA film increases the optical path of the reflected light (the light passes through the transparent layer to reach the reflective EVA, and the reflected light needs to pass through the transparent layer again to reach the cell again) to reduce the reflection effect of the reflective material. In addition, the non-woven fabric is a highly crystalline material, which is difficult to integrate with the encapsulant and introduces weak links.

Summary of the invention

The object of the present invention is to overcome the above deficiencies, and to provide a solar cell encapsulant and a preparation method thereof, which can not overflow, does not cause lines and wrinkles, and can ensure sufficient cross-linking degree and bonding. effect.

The technical solution adopted by the invention is:

A solar cell encapsulant comprising at least two layers of a film, comprising an encapsulant layer and at least one functional film layer, or other layers may be added as a transition layer, wherein the functional film has less fluidity than the encapsulant The fluidity of the layer.

The functional film has a weak link caused by punching or embossing.

The fluidity of the functional film is characterized by a melt index, which is less than 20 g/10 min below 150 ° C, and the functional film may be transparent or white or other colors.

The functional film may be selected from one or more of PET, POE, PVC, EVA, PE, PIB, IIR, PP and the like. Additives such as adhesion promoters may also be added to improve performance or to add fillers.

The thickness of the functional film is between 0.0001 mm and 1 mm, preferably between 0.001 mm and 0.5 mm.

The encapsulant layer is preferably a white EVA layer.

The encapsulating layer and the transition film layer have a melt index of less than 150 g/10 min.

a method for preparing the above solar cell encapsulant;

It can be prepared by integrally forming a functional film, an encapsulant layer or a functional film with an encapsulant layer and a transition layer; A separate preparation method is employed. For example, the functional film and the encapsulant layer, or the functional film and the encapsulant layer, and the transition film layer are composited by coating; or the double-layer or multi-layer co-extrusion method is combined; or the functional film and the encapsulant layer are separately prepared. The transition film layer is laminated in the order of lamination, and is combined by temperature and pressure during lamination; or one or two layers are prepared first, and the other layer is prepared with the layer already prepared. Pressing or compounding with an adhesive; or laminating by lamination, or other methods.

In addition, it should be pointed out that after the functional film is compounded with the common encapsulant, since the compounding can be carried out when all or one of the encapsulant and the functional film is in a viscous flow state, the two films may not easily separate the obvious boundaries. Under the addition of the functional film, the encapsulant has uneven fluidity in the thickness direction. The encapsulant melts during lamination and fuses at the interface, resulting in a non-obvious boundary between the functional film and the encapsulant. The fluidity near the side of the functional film is small, and the fluidity away from the side of the functional film is large. In many cases, the encapsulant has a certain thermal cross-linking during lamination, and the fluidity is greatly reduced, and the fluidity before cross-linking cannot be judged. At this time, it should be judged from the processing technology and raw materials of the two films. The cross-linking type encapsulant layer is processed to avoid gelation at higher temperatures, and its processing temperature is limited. However, due to poor fluidity of the functional film, it is necessary to ensure that the production line speed is seriously affected, and the production efficiency is required to be high. Melt temperature. Therefore, the processing temperature of the functional film is generally higher than the processing temperature of the encapsulant layer, and needs to be processed separately. And the raw materials used for the two films have different fluidity.

The invention utilizes a layer of functional film with low fluidity to be compounded with the encapsulant layer, and can be melt-hot pressed composite, directly laid or other composite method, since the functional film itself has less fluidity than the encapsulant layer, on the one hand, it is more than the encapsulant The layer is more difficult to overflow and has a good limiting effect on the overflow of higher flow encapsulants. On the other hand, since the functional film has less fluidity than the encapsulant, the functional film with lower fluidity during lamination will restrict and restrain the flow of the encapsulating adhesive with higher fluidity, so that the encapsulant flows when “ The grain generated on the interface of the transparent-dyeing is not obvious or even completely disappeared, so the phenomenon of lines and wrinkles is greatly improved.

The functional film can also be used for the face-up surface and is compounded with a transparent encapsulant on the mater surface. The backlight surface adopts a white or other color poorly transmissive encapsulant similar in fluidity to the transparent encapsulant. When laminating, the functional film faces the cell. In areas other than the component cell, the functional film directly contacts the backside white (or other color) encapsulant. The function of the functional film to improve the overflow and texture is similar to that of the back surface; since its fluidity is less than that of the back white (or other color) encapsulant, its flow in the thickness direction is limited, thereby controlling the overflow. Phenomenon; at the same time, the functional film with low fluidity will play a role in the flow of the highly fluid back encapsulant in the horizontal plane, avoiding the formation of wrinkles or wrinkles on the "transparent-white (or other color)" interface.

The invention can use the existing encapsulant formulation and process to make the encapsulant, and ensure that the adhesion of the encapsulant to the back sheet or the back surface glass is not affected.

The punching function film or some weak links such as patterns are formed on the functional film, and then compounded with the encapsulating layer. Under the influence of temperature and pressure during lamination, the encapsulating glue may seep through the holes or weak links to ensure leakage. a certain amount of adhesion; On the other hand, the amount of glue that is exuded is controlled, and the overflow of the back encapsulant can also be avoided. After testing, it was confirmed that the solar cell made of the punched functional film composite white (or other color) encapsulant layer has great improvement in both the control of the overflow and the control of the grain. A film with a strong composite bond strength on the functional film is used as a transition layer, and the color thereof may be a transparent or white light having a low light transmittance (if the functional film is located on the light-facing surface, the functional film layer and the transition layer are also required to be secured). Sufficient light transmittance) can further improve performance. After testing, the adhesive obtained by this method, the appearance or the functional film surface adhesion can meet the requirements.

A material having a melting temperature of 150 ° C or less is used as a functional film, and in order to improve its performance, some additives may be added thereto, and then compounded with the encapsulant layer as a whole of the encapsulant. Two or more components may also be used as the main material of the functional film to be compounded with the encapsulant body. Other layers can also be added as a transition layer. A material that is more adhesive and less prone to overflow or texture, such as polyvinyl butyral as a functional film material, can also achieve an improved appearance. This patent has been proved by experiments that the material is difficult to produce appearance problems such as overflow and texture. It is believed that with the development of technology, more materials that meet the requirements and are inexpensive will be developed. However, under the same conditions, the method proposed in this patent will effectively improve or even completely eliminate the overflow. Wrinkling phenomenon.

The advantages of the present invention over the prior art are:

1, the functional film or other film layers in the system can be used in a variety of materials, such as PET, PVC, PE and other materials with many other advantages. Thereby, the water vapor transmission rate of the entire back encapsulant can be reduced, the material cost can be reduced, the bulk resistance can be improved, the component PID effect can be reduced, the anti-yellowing property of the encapsulant can be improved, and the like, and the packaging tape has an additional advantage.

2. Since the functional film does not overflow itself, it can also be added with a high reflectivity filler to improve the reflectivity without necessarily maintaining its high transparency. (For example, some products on the market use a transparent EVA layer to isolate the white EVA layer and Cell: In addition, the method disclosed in Patent 201220587305.3 also uses a transparent layer to isolate the white EVA and the cell sheet, thereby improving the reflection effect. At the same time, the amount of reflective filler required to achieve the same reflectivity can be greatly reduced, thereby saving costs.

3, the material cost is low, the cost of the film of the same material is generally lower than the non-woven fabric, glass fiber.

4. This design can maintain sufficient cross-linking degree of the encapsulant, or the degree of cross-linking is almost unaffected.

5. The punching function film is compounded with the encapsulant to ensure sufficient adhesion. Some lines are pressed on the film to create some weak links. During the lamination process, the encapsulant can penetrate these weak points to achieve similar effects to the perforated film.

6, using a suitable material (melting temperature below the lamination temperature) can make the functional film layer soften and melt under the temperature conditions of lamination, can be well fused with the encapsulant film layer, with glass fiber or non-woven fabric Compared with materials that are not melted during lamination, no foreign matter is introduced into the encapsulant, resulting in a weak link.

7. The present invention captures the key causes of appearance problems such as overflow and texture, and the method has better effects on the control of wrinkles and textures. Simply rely on the transparent layer for blocking (such as some products on the market use a transparent EVA layer to isolate the white EVA layer and the battery sheet to prevent overflow: as disclosed in patent 201220587305.3, it is also transparent Although the layer-isolated white EVA and the battery sheet have a certain effect on avoiding overflow, the effect of improving the wrinkles and texture problems in the area without the battery sheet in the solar module is very limited.

This patent proves through experiments that between the battery sheet and the back encapsulant, it is not necessary to add a transparent film to prevent the over-package adhesive from overflowing (such as white or other colors) from overflowing, as described in this patent. In this way, the battery sheet can also directly contact the back surface sealing film with poor transparency, so that it can reflect sunlight or conduct heat or perform other functions more directly, and ensure that the appearance of the component is poor (such as overflow and texture). Improvement until completely eliminated. The bonding effect and crosslinking degree of the entire system are within an acceptable range.

DRAWINGS

Figure 1 is a structure of a general solar cell;

2 is a solar cell encapsulant structure of the present invention;

Among them, 1. Yingguang surface glass, 2. Yingguang surface encapsulation adhesive overall, 3. Cell sheet, 4. Back surface encapsulation adhesive whole, 5. Back sheet or glass, 6. Functional film, 7. Encapsulation layer.

Detailed ways

This will be further explained below in conjunction with the examples.

Example 1

A solar cell encapsulant comprises a layer of encapsulant and a layer of functional film in sequence. The functional film is laminated with the encapsulant layer. When laminating, the functional film surface is close to the cell sheet, and the encapsulant layer is close to the back plate side. The functional film has a fluidity less than that of the encapsulant layer, and the encapsulant layer is white EVA, and the whole of the functional film and the encapsulant is used as the back encapsulant as a whole.

preparation;

In terms of parts by mass, 100 parts of vinyl acetate content of 32% by weight, MI of 40 g/10 min (test method ASTM D1238, 190 ° C, 2.16 kg, the same below) of EVA pellets, 6 parts of rutile titanium dioxide, 0.5 parts of γ - methacryloxypropyltrimethoxysilane, 1 part t-butyl-(2-ethylhexyl) monoperoxycarbonate, 0.5 part triallyl isocyanurate, 0.2 part 2- The hydroxy-4-n-octyloxybenzophenone is uniformly mixed by a mixer to serve as a raw material for the encapsulant layer.

In parts by mass, 100 parts of EVA masterbatch having a vinyl acetate content of 28% by weight and a MI of 10 g/10 min, 6 parts of rutile-type titanium dioxide and 2 parts of γ-methacryloxypropyltrimethoxysilane were added. 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone was uniformly mixed and used as a functional film raw material. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.2 mm.

The temperature of the control layer is 80-90 degrees Celsius, and the raw material of the encapsulating layer is extruded, stretched, drawn, and compounded with the functional film to form a 0.4 mm back encapsulant as a whole.

The face of the mating surface is made of Foster F806 transparent EVA film.

The photovoltaic glass, the glossy surface encapsulant as a whole, the cell sheet, the back encapsulant as a whole, and the back sheet were laminated in this order, and the functional film surface was oriented toward the cell sheet, and the module size was 45×45 cm, laminated and evaluated for appearance.

Example 2

A solar cell encapsulant comprising a functional film on one side of the cell sheet and an encapsulant layer on the side of the back sheet or glass. The functional film is compounded with the encapsulant layer, the functional film has less fluidity than the encapsulant layer, the encapsulant layer is white EVA, and the functional film and the encapsulant are integrally formed as the back encapsulant as a whole, and the face-face package is packaged. The glue is entirely made of transparent EVA film on the market, such as Foster F806. When laminated, the functional film surface is in close proximity to the cell sheet.

preparation:

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight, MI of 40 g/10 min, 6 parts of rutile-type titanium oxide, 0.5 parts of γ-methacryloxypropyltrimethoxysilane, 1 Part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, and 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone are uniformly mixed. As a raw material for the encapsulant layer.

In parts by mass, 100 parts of EVA masterbatch having a vinyl acetate content of 28% by weight and a MI of 3 g/10 min was added to 6 parts of rutile-type titanium dioxide and 2 parts of γ-methacryloxypropyltrimethoxysilane, 0.2. The 2-hydroxy-4-n-octyloxybenzophenone is uniformly mixed as a raw material of the functional film. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.1 mm.

The encapsulating rubber layer material is extruded at 80 to 90 degrees Celsius, stretched, drawn, and controlled at a temperature of 70 to 90 degrees to be combined with a functional film by hot pressing to form a 0.4 mm back encapsulant as a whole.

The face of the mating surface is made of Foster F806 transparent EVA film.

The whole surface and the back surface encapsulant of the mating surface encapsulant are laminated and packaged as a light-emitting and backlight surface EVA. The functional film surface is adjacent to the cell sheet, and the module size is 45×45 cm. .

Example 3

A solar cell encapsulant comprises a functional film on one side of the cell sheet, an encapsulant layer on the side of the back sheet or the glass, and a transition layer distributed on the side of the functional film near the cell sheet. The functional film is compounded with the encapsulant layer and the transition layer. The functional film has less fluidity than the encapsulant layer and the transition layer, and the encapsulant layer is white EVA, and the functional film layer, the transition layer and the encapsulant are integrated. As a whole of the back encapsulant, the face-up package is made of a transparent EVA film on the market, such as the Foster F806. The transition layer is in close proximity to the cell sheet during lamination.

preparation:

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer.

In terms of parts by mass, 100 parts of EVA masterbatch having a vinyl acetate content of 33% by weight and an MI of 30 g/10 min, 6 parts of rutile-type titanium dioxide, 2.5 parts of γ-methacryloxypropyltrimethoxysilane, 0.5 parts of triallyl isocyanurate, 1 part of tert-butyl-(2-ethylhexyl) monoperoxycarbonate, 0.2 parts of 2-hydroxy-4-n-octyloxybenzophenone, mixed Uniform, as a raw material for the transition layer.

A 0.003 mm BOPP film was used as the functional film. The temperature was controlled to 90 degrees, and a 0.02 mm thick transition layer was laminated thereon to form a composite film 1.

The temperature of the sealing layer is controlled at 80-90 degrees Celsius. The material of the encapsulating layer is extruded, stretched, drawn, and composited with the composite film 1. The transition layer is closely attached to the functional film layer; the functional film layer is closely attached to the sealing layer to form the back package. Glue overall.

The face masking adhesive is made of Foster F806 transparent EVA film.

The whole face and back package rubber of the face-up package are laminated as a light-emitting and backlight surface EVA. When the backlight surface encapsulant is integrally laminated, the transition layer directly contacts the cell sheet, and the component size is 45×45 cm.

Example 4

A solar cell encapsulant comprising a functional film on one side of the cell sheet and an encapsulant layer on the side of the back sheet or glass. The functional film is compounded with the encapsulant layer, the functional film has less fluidity than the encapsulant layer, the encapsulant layer is white EVA, and the functional film and the encapsulant are integrally formed as the back encapsulant as a whole, and the face-face package is packaged. The glue is made of a transparent EVA film on the market, such as the Foster F806. When laminated, the functional film surface is in close proximity to the cell sheet.

preparation:

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl) monoperoxycarbonate, 0.5 part of triallyl isocyanate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer.

In parts by mass, 30 parts of PP masterbatch (MI is 2.8 g/10 min), and 70 parts of EVA masterbatch with a vinyl acetate content of 28 wt%, MI of 3 g/10 min, and 6 parts of rutile titanium dioxide, 2.5 parts Γ-methacryloxypropyltrimethoxysilane, 0.2 parts of 2-hydroxy-4-n-octyloxybenzophenone, uniformly mixed, and stretched to form a functional film having a thickness of about 0.03 mm, and Punch holes. The pore size was 0.2 mm and the density was 49 / cm ² .

The temperature of the control layer is 80-90 degrees Celsius, and the raw material of the package rubber layer is extruded, stretched, drawn, and compounded with the functional film to form a whole package of the back surface sealant.

The face masking adhesive is made of Foster F806 transparent EVA film.

The whole face and back package rubber of the face-up package are laminated as a light-emitting and backlight surface EVA. Among them, the functional film in the whole of the back encapsulant directly contacts the cell sheet, and the module size is 45×45 cm.

Example 5

A solar cell encapsulant comprising a functional film on one side of the cell sheet and an encapsulant layer on the side of the back sheet or glass. The functional film is compounded with the encapsulant layer, and the functional film has a fluidity smaller than that of the encapsulant layer, and the integral structure of the functional film and the encapsulant film made of white EVA is used as the backlight encapsulant as a whole. Foster EVA F806 is used as a mating surface encapsulant.

preparation;

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part tert-butyl-(2-ethylhexyl) monoperoxycarbonate, 0.5 part triallyl isocyanurate, 0-2 part 2-hydroxy-4-n-octyloxybenzophenone It is evenly mixed by the mixer and used as a raw material for the encapsulant layer.

In terms of parts by mass, 100 parts of EVA masterbatch having a VA of 28% and an MI of 3 g/10 min, 6 parts of rutile-type titanium oxide, and uniformly mixed were used as a functional film raw material. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.1 mm.

The encapsulant layer and the functional film are heat-compressed at a temperature of about 80 degrees Celsius, and the white side of the encapsulant layer is adjacent to the functional film. The main material is made of EVA's back encapsulant as a whole.

The face of the mating surface is made of Foster F806 transparent EVA film.

The whole face and back side encapsulant of the face-up package are laminated as a light-emitting and back-face EVA. The functional film in the back package is directly in contact with the cell, and the appearance is evaluated. The component size is 45×45 cm.

Example 6

A solar cell encapsulant comprising a functional film layer on one side of the cell sheet and an encapsulant layer on the side of the back sheet or glass. The functional film is compounded with the encapsulant layer, the functional film has less fluidity than the encapsulant layer, the encapsulant layer is white EVA, and the functional film and the encapsulant are integrally formed as the back encapsulant as a whole, and the face-face package is packaged. The glue is made of a transparent EVA film on the market, such as the Foster F806. When laminated, the functional film surface is in close proximity to the cell sheet.

preparation:

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 36% by weight and an MI of 40 g/10 min, 6 parts of rutile-type titanium dioxide, 0.5 parts of γ-methacryloxypropyltrimethoxysilane, 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer.

In terms of parts by mass, 100 parts of EVA masterbatch having a MI of 3 g/10 min and a VA content of 28%, 6 parts of rutile-type titanium dioxide, 2 parts of γ-methacryloxypropyltrimethoxysilane, 0.2 2-hydroxy-4-n-octyloxybenzophenone The ketone is uniformly mixed by a mixer to serve as a raw material for the functional film layer 1. The functional film layer 1 raw material is stretched, guided, and wound to form a functional film layer 1 having a thickness of about 0.04 mm.

In parts by mass, 100 parts of HDPE masterbatch with a MI of 0.1 g/10 min, 5 parts of rutile-type titanium dioxide, 2 parts of vinyltris(β-methoxyethoxy)silane, and 1 part of γ-methyl are added. Acryloyloxypropyltrimethoxysilane and 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone were uniformly mixed to form a raw material of the functional film layer 2. The functional film layer 2 raw material is stretched, guided, and wound to form a functional film layer 2 having a thickness of about 0.04 mm.

In terms of parts by mass, 100 parts of EVA masterbatch having a MI of 5 g/10 min and a VA content of 24%, 5 parts of rutile-type titanium dioxide, 2 parts of γ-methacryloxypropyltrimethoxysilane, 0.2 The 2-hydroxy-4-n-octyloxybenzophenone is uniformly mixed and used as a raw material of the functional film layer 3. The functional film layer 3 raw material is stretched, guided, and wound to form a functional film layer 3 having a thickness of about 0.04 mm.

The temperature of the control film is 80-90 degrees Celsius, the encapsulating film layer is extruded, stretched, guided, and sequentially combined with the functional film layers 1, 2, and 3 to form a back-side encapsulating film as a whole.

The face of the mating surface is made of Foster F806 transparent EVA film.

The whole surface and back surface encapsulant of the mating surface encapsulant are laminated and packaged as a mating and backlighting encapsulant. The functional film surface directly contacts the cell sheet, and the appearance is evaluated. The component size is 45×45 cm.

Example 7

A solar cell encapsulant comprising a functional film on one side of the cell sheet and an encapsulant layer on the side adjacent to the glass. The functional film is compounded with the encapsulant layer. The functional film has less fluidity than the encapsulant layer, and the encapsulant layer is selected by Foster F806 transparent EVA film. The encapsulant made of the functional film and the Foster EVA film is used as a whole for the face-up package, and is used together with the white EVA as the back package film.

preparation:

The Foster F806 transparent EVA film is used as the coating layer for the mating surface.

In terms of parts by mass, 100 parts of EVA masterbatch having a vinyl acetate content of 33% by weight and an MI of 4 g/10 min, 2 parts of γ-aminopropyltriethoxysilane, 0.2 parts of hindered amine light stabilizer, and evenly mixed As a functional film raw material. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.03 mm.

The functional film and the mating surface encapsulant layer (Foster F806 transparent EVA film) are heat-compressed at a temperature of about 80 degrees Celsius to form a whole surface encapsulating adhesive of EVA.

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer to form a back encapsulant having a thickness of 0.37 mm.

The whole surface of the mating surface encapsulant and the back surface encapsulant are laminated as a light-emitting and backlight surface EVA, and the functional film surface is tightly attached to the cell. The module size is 45×45 cm, and the appearance is evaluated.

Example 8

A solar cell encapsulant comprises a layer of encapsulant and a layer of functional film in sequence. The functional film is compounded with the encapsulant layer, the functional film has less fluidity than the encapsulant layer, the encapsulant layer is white EVA, and the functional film and the encapsulant are integrally formed as the back encapsulant as a whole, and the face-face package is packaged. The glue is made of a transparent EVA film on the market, such as the Foster F806. When laminated, the functional film surface is in close proximity to the cell sheet.

preparation:

In terms of parts by mass, 100 parts of EVA masterbatch having a vinyl acetate content of 22% by weight and an MI of 20 g/10 min, 6 parts of rutile-type titanium dioxide and 2 parts of γ-methacryloxypropyltrimethoxysilane are added. 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone was uniformly mixed by a mixture to serve as a functional film raw material. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.1 mm.

The temperature of the control layer is 80-90 degrees Celsius, and the raw material of the encapsulating layer is extruded, stretched, drawn, and pressed with the functional film to form the whole backing encapsulant of the main material as EVA.

The face of the mating surface is made of Foster F806 transparent EVA film.

The photovoltaic glass, the whole surface of the mating surface encapsulant, the cell sheet, the back encapsulant, and the back sheet were laminated in this order, and the functional film layer was laminated next to the cell sheet, and laminated, and the module size was 45×45 cm, and the appearance was evaluated.

Example 9

A solar cell encapsulant comprises a layer of encapsulant layer, a layer of functional film and a layer of transition layer. The functional film layer and the transition layer are combined with the encapsulant layer. The functional film has a fluidity less than that of the encapsulant layer, and the whole of the functional film and the encapsulant is used as the back encapsulant as a whole.

preparation;

The Foster F806 was chosen as the transition layer.

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and a MI of 30 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The granulator was uniformly mixed and used as a raw material for the encapsulant layer to form an encapsulant layer having a thickness of 0.35 mm.

In parts by mass, 100 parts of POE particles having a MI of 3 g/10 min, 6 parts of rutile type titanium dioxide, 2 parts of γ-methacryloxypropyltrimethoxysilane, and 0.2 parts of 2-hydroxy-4- are added. The n-octyloxybenzophenone is uniformly mixed and used as a raw material for the functional film layer. The functional film raw material is stretched, drawn, and wound to form a functional film having a thickness of about 0.05 mm.

The encapsulating adhesive layer and the functional film and the transition layer are heat-compressed at a temperature of about 80 degrees Celsius in turn to form a back encapsulant as a main material of the EVA.

The face of the mating surface is made of Foster F806 transparent EVA film.

The photovoltaic glass, the mating surface encapsulant as a whole, the cell sheet, the back encapsulant as a whole (the transition layer directly contacts the cell sheet), the back sheet were laminated, and laminated, and the module size was 45×45 cm, and the appearance was evaluated.

Example 10

A solar cell encapsulant comprises a functional film layer, a layer of encapsulating film, and a functional film layer. The functional film layer is compounded with the encapsulant film layer, the functional film layer has a fluidity smaller than that of the encapsulant film layer, and the encapsulant film layer is a white EVA layer. The whole of the functional film layer and the encapsulant film layer is used as the whole of the back surface encapsulant, and the glossy surface encapsulant is selected from a transparent EVA film on the market, such as Foster F806.

preparation;

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight, MI of 40 g/10 min, 6 parts of rutile-type titanium oxide, 0.5 parts of γ-methacryloxypropyltrimethoxysilane, 1 Part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer.

In terms of parts by mass, 100 parts of EVA masterbatch having a MI of 3 g/10 min and a VA content of 28%, 6 parts of rutile-type titanium dioxide, 2 parts of γ-methacryloxypropyltrimethoxysilane, 0.2 The 2-hydroxy-4-n-octyloxybenzophenone is uniformly mixed by a mixer to serve as a raw material for the functional film layer. The functional film layer material is stretched, guided, and wound to form a functional film layer having a thickness of about 0.08 mm.

The three layers of the functional film layer, the encapsulant film layer and the functional film layer are sequentially thermocompression-bonded at 90 degrees Celsius to form a back-side encapsulant as a whole.

The face of the mating surface is made of Foster F806 transparent EVA film.

The whole face and back side encapsulant of the face-up package were laminated and packaged as a mating and back-face encapsulant, and the appearance was evaluated. The component size was 45×45 cm.

Comparative example 1

A solar cell encapsulant, the transparent face encapsulant is selected from a transparent EVA film on the market, such as Foster F806. The backlight package is white.

preparation:

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 part of 2-hydroxy-4-n-octyloxybenzophenone mixed uniformly As a raw material for the back surface encapsulant layer. At 80-90 degrees Celsius, the raw material of the encapsulating layer is kneaded, stretched, and drawn to form a white backing encapsulant as a main material of EVA.

The face of the mating surface is made of Foster F806 transparent EVA film.

The photovoltaic glass, the mating surface encapsulant as a whole, the cell sheet, the back encapsulant as a whole, and the back sheet were laminated and laminated, and the module size was 45×45 cm, and the appearance was evaluated.

Comparative example 2

preparation:

The Foster F806 is used as the whole surface of the mating surface encapsulant; the back encapsulant is entirely made of Foster F806 and white EVA layer.

In terms of parts by mass, 100 parts of EVA pellets having a vinyl acetate content of 32% by weight and an MI of 40 g/10 min were added, and 6 parts of rutile-type titanium oxide and 0.5 part of γ-methacryloxypropyltrimethoxysilane were added. 1 part of tert-butyl-(2-ethylhexyl)monoperoxycarbonate, 0.5 part of triallyl isocyanurate, 0.2 valence of 2-hydroxy-4-n-octyloxybenzophenone The machine is evenly mixed and used as a raw material for the encapsulant layer.

The photovoltaic glass, the face-up package, the cell sheet, the Foster F806, the white EVA layer, and the back sheet were laminated and laminated, and the module size was 45×45 cm, and the appearance was evaluated.

Performance Testing:

1, peel strength with glass

The peel strength of the functional film surface and the photovoltaic glass in the entire packaged adhesive with a functional film in the present invention was tested in accordance with the ASTM D903 experimental method.

2, appearance

According to the lamination and lamination method of the general assembly, the lamination temperature was 145 ° C, the evacuation time was 5 minutes, and the solar cell module was fabricated for 14 minutes to observe the appearance. All the examples and comparative examples were laminated under the same lamination conditions, and the module size was 45×45 cm. Compare the appearance.

3, cross-linking degree

After lamination, the degree of crosslinking of the encapsulant was tested, and the degree of crosslinking was tested by the DSC method.

Test principle: When the sealant is crosslinked, heat is released. The heat released by the encapsulating adhesive after curing and the cross-linking after curing (curing enthalpy) was recorded by DSC, and then the cross-linking degree after cross-linking was calculated. The calculation formula is as follows: Gel Content%=(uncrosslinked curing 焓After curing, the remaining curing 焓) / uncrosslinked curing 焓.

Test method: first put the uncrosslinked encapsulant into the DSC instrument, and raise it from room temperature to 230 ° C, and then hold it at 230 ° C for 5 min to obtain uncrosslinked solidified crucible. The test conditions were selected: heating rate 10 ° C / rain, purge gas N 2 , flow rate 30 ml / min. The same quality cross-linked encapsulant was selected and tested under the same test conditions to obtain the remaining solidified crucible after cross-linking. By using the above formula to calculate, the degree of crosslinking of the cross-linked encapsulant can be obtained.

Performance test results:

Claims

A solar cell encapsulant structure characterized by being composed of at least two layers of a film, comprising an encapsulant layer and at least one functional film layer, or comprising an encapsulant layer and at least one functional film layer and an adjacent functional film At least one transition layer of the layer, the fluidity of the functional film layer is less than the fluidity of the encapsulant layer.
The solar cell encapsulant structure according to claim 1, wherein the functional film has a weak link caused by punching or embossing or scratching or thickness difference.
The solar cell encapsulant structure according to claim 1, wherein the functional film has a fluidity of less than 80 to 150 ° C and less than a fluidity of the encapsulant layer.
The solar cell encapsulant structure according to claim 1, wherein the fluidity of the functional film is characterized by a melt index of less than 20 g/10 min below 80 to 150 °C.
The solar cell encapsulant structure according to claim 1, wherein the functional film is selected from the group consisting of EVA, PVB, PE, PC, PBT, PET, PU, PPO, PA, PP, PAN, PS, PB, Mixing one or more of ABS, PIB, rubber, polyester, polyolefin or PVC and their modifications, preferably materials having a melting temperature below 150 degrees Celsius.
The solar cell encapsulant structure according to claim 1, wherein the functional film has a thickness of between 0.0001 mm and 1 mm.
The solar cell encapsulant structure according to claim 6, wherein the functional film has a thickness of between 0.001 mm and 0.5 mm.
The solar cell encapsulant structure according to claim 1, wherein the encapsulant layer is a white EVA layer.
The method for preparing a solar cell encapsulant structure according to any one of claims 1 to 7, characterized in that

Preparing a functional film, an encapsulant layer or a functional film together with an encapsulant layer and other layers by integral molding; or using a separately prepared method; or a functional film and an encapsulant layer, or a functional film and an encapsulant layer, and other layers Coated by coating; or double-layered, multi-layer co-extrusion; or separately made functional film, encapsulant layer and other layers, laminated each film in order, by lamination The temperature and pressure are combined to make it; or one or two layers are prepared first, and the other layer is heat-compressed with the prepared layer or compounded by means of an adhesive; or laminated by lamination; or sprayed on one layer The other layers are composited; or by ultrasonic compounding.