CN116072753B

CN116072753B - Photovoltaic module and preparation method

Info

Publication number: CN116072753B
Application number: CN202310089709.2A
Authority: CN
Inventors: 郝国晖; 黄世亮; 郭志球
Original assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Current assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Priority date: 2023-01-16
Filing date: 2023-01-16
Publication date: 2024-05-10
Anticipated expiration: 2043-01-16
Also published as: CN116072753A

Abstract

The embodiment of the application relates to the field of photovoltaics, and provides a photovoltaic module and a preparation method thereof, wherein the photovoltaic module comprises a plurality of battery pieces, and each battery piece comprises grid line structures which are arranged at intervals along a first direction; the connecting parts are arranged at intervals along the second direction, are positioned on the surfaces of the battery pieces and the surfaces of the grid line structures, and are respectively and electrically connected with the adjacent battery pieces; a plurality of composite films, wherein the composite films cover the surfaces of the connecting parts, and the two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a blocking layer, and the adhesive layer is positioned between the blocking layer and the connecting part; the packaging layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer; and the cover plate is positioned on one side of the packaging layer far away from the battery piece. The photovoltaic module and the preparation method provided by the embodiment of the application can at least improve the yield of the photovoltaic module.

Description

Photovoltaic module and preparation method

Technical Field

The embodiment of the application relates to the field of photovoltaics, in particular to a photovoltaic module and a preparation method thereof.

Background

Solar cells are devices that directly convert light energy into electrical energy through a photoelectric effect or a photochemical effect. The single solar cell cannot be directly used for power generation. Several single batteries must be connected in series and parallel by welding strips and tightly packaged into a module for use. Solar cell modules (also called solar panels) are the core part of and the most important part of a solar power generation system. The solar cell module is used for converting solar energy into electric energy, or sending the electric energy to a storage battery for storage, or pushing a load to work.

The battery piece is very fragile, and the upper and lower surfaces of the battery assembly are generally required to be provided with adhesive films and cover plates for protecting the battery piece. The cover plate is generally made of photovoltaic glass, the photovoltaic glass cannot be directly attached to the battery piece, and the adhesive film is required to be adhered in the middle. The connection between the battery cells typically requires a solder strip for collecting current, and conventional solder strips require alloying between the solder strip and the fine grid by welding during soldering. The melting point of the solder in the solder strip is then generally higher, and in the actual soldering process, the soldering temperature is 20 ℃ above the melting point of the solder. The battery piece is large in buckling deformation in the welding process, so that the hidden cracking risk after welding is large, and the breaking rate is high. Especially for PERC batteries (PASSIVATED EMITTER AND REAR CELL, passivated emitter and back batteries), the internal stress is larger, buckling deformation and chipping are more likely to occur after welding, and the assembly repair rate is increased and the yield is reduced. In the above background, in order to improve the welding quality, the low temperature solder strip and no main grid technology are generated. There are many factors that affect the yield of the assembly, such as the effect of the solder between the solder strip and the fine grid, the yield of the solder, and the like.

Disclosure of Invention

The embodiment of the application provides a photovoltaic module and a preparation method thereof, which are at least beneficial to improving the yield of the photovoltaic module.

According to some embodiments of the present application, an aspect of an embodiment of the present application provides a photovoltaic module, including: each battery piece comprises grid line structures which are arranged at intervals along a first direction; the connecting parts are arranged at intervals along the second direction and are positioned on the surface of the battery piece and the surface of the grid line structure, and the connecting parts are respectively and electrically connected with the adjacent battery pieces; the composite films cover the surfaces of the connecting parts, and two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a barrier layer, wherein the adhesive layer is positioned between the barrier layer and the connecting part; the packaging layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer; and the cover plate is positioned on one side of the packaging layer away from the battery piece.

In some embodiments, the spacing between adjacent composite films is less than 5/6 of the spacing of adjacent connection members.

In some embodiments, the ratio of the thickness of the adhesive layer to the thickness of the barrier layer is 1/5 to 75.

In some embodiments, the barrier layer surrounds a portion of the adhesive layer.

In some embodiments, in the second direction, adjacent composite films are continuous film layers.

In some embodiments, the viscosity of the adhesive layer is greater than the viscosity of the barrier layer at the same predetermined temperature.

In some embodiments, the material of the barrier layer is different from the material of the adhesive layer; the water permeability of the material of the barrier layer is in the range of 2-4 g/m ².

In some embodiments, the material of the barrier layer comprises PET, POE, liquid silicone, or PVB.

In some embodiments, further comprising: the glue points are positioned on the surface of the battery piece and between the adjacent grid line structures; the connecting part is positioned on the glue point.

In some embodiments, the glass transition temperature of the adhesive layer ranges from-55 to 0 ℃.

In some embodiments, the barrier layer has a glass transition temperature in the range of 100 to 200 ℃.

According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a method for manufacturing a photovoltaic module, including: providing a plurality of battery pieces, wherein each battery piece comprises grid line structures which are arranged at intervals along a first direction; providing a plurality of connecting components which are arranged at intervals along a second direction, wherein the connecting components are positioned on the surface of the battery piece and are electrically connected with the adjacent battery pieces; providing a plurality of composite films, wherein the composite films cover the surfaces of the connecting parts, and two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a barrier layer, wherein the adhesive layer is positioned between the barrier layer and the connecting part; providing an encapsulation layer, wherein the encapsulation layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer; providing a cover plate, wherein the cover plate is positioned on one side of the packaging layer far away from the battery piece; laminating treatment is performed.

In some embodiments, the process for preparing the composite film comprises: uniformly mixing the raw materials of the adhesive layer according to the proportion, extruding the mixture through extrusion equipment to form a first raw material, uniformly mixing the raw materials of the barrier layer according to the proportion, and extruding the mixture through extrusion equipment to form a second raw material; pouring one of the first raw material or the second raw material into forming equipment according to the proportion to form an initial film; and (3) co-extrusion compounding, namely pouring the other one of the first raw material and the second raw material into the forming equipment, and forming the composite film through screw extrusion compounding.

The technical scheme provided by the embodiment of the application has at least the following advantages:

In the technical scheme provided by the embodiment of the application, on one hand, a layer of composite film is arranged between the connecting component and the packaging layer, the composite film covers the surface of the connecting component, the composite film comprises an adhesive layer and a barrier layer, the adhesive layer can be used for fixing the relative position between the connecting component and the battery piece, and the connecting component is prevented from being deviated due to the fact that the connecting component is pushed by the packaging layer in a molten state; the barrier layer is used for blocking the molten packaging layer from flowing between the connecting part and the battery piece during lamination treatment, so that the problem of electric connection between the battery piece and the connecting part is caused, the weldability of the assembly is improved, the tensile force in the welding strip direction is improved, the welding quality of the assembly is improved, the problems of cold welding of the assembly and the like are reduced, the product quality of the assembly is improved, the abnormality such as repair in the assembly manufacturing process is reduced, and the productivity of the assembly is greatly improved. On the other hand, the glass transition temperature of at least one of the adhesive layer and the barrier layer is larger than that of the packaging layer, and the packaging layer is in a molten state in the lamination process, but one of the adhesive layer and the barrier layer is in a relatively compact solid state, so that the molten adhesive film can be prevented from flowing between the grid line structure and the connecting part. In addition, the adhesive layer and the barrier layer can also be used as a part of the packaging layer, so that on one hand, the thickness of an adhesive film on the surface of the connecting component is prevented from being thinner, and the connecting component has the risk of penetrating through the packaging layer; the composite film can also be used to insulate moisture to improve the performance of the gate line structure.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise. One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present application;

FIG. 2 is a schematic cross-sectional view of the structure of FIG. 1 along the section c ₁-c₂;

FIG. 3 is a schematic view of a first cross-sectional structure of FIG. 1 along the section a ₁-a₂;

fig. 4 is a schematic view of a first structure of a composite film in a photovoltaic module according to an embodiment of the present application;

FIG. 5 is a schematic view of a second cross-sectional structure taken along the line a ₁-a₂ in FIG. 1;

fig. 6 is a schematic view of a second structure of a composite film in a photovoltaic module according to an embodiment of the present application;

FIG. 7 is a schematic view of a third cross-sectional structure taken along the line a ₁-a₂ in FIG. 1;

Fig. 8 is a schematic view of a third structure of a composite film in a photovoltaic module according to an embodiment of the present application;

Fig. 9 is a schematic diagram of a second structure of a photovoltaic module according to an embodiment of the present application;

FIG. 10 is a schematic cross-sectional view of the structure of FIG. 9 along the section c ₁-c₂;

fig. 11 is a schematic view of a third structure of a photovoltaic module according to an embodiment of the present application;

fig. 12 is a schematic view of a fourth structure of a photovoltaic module according to an embodiment of the present application;

Fig. 13 is a schematic cross-sectional view of fig. 12 along the section b ₁-b₂.

Detailed Description

As known from the background art, the yield of the current photovoltaic module is poor.

Analysis shows that one of the reasons for the poor yield of the photovoltaic module is that sunlight enters the cell from the front side of the cell, a part of silicon wafers is shielded by a metal electrode on the front side, and the part of light energy which irradiates on the electrode cannot be converted into electric energy, so that the finer the grid line is, the better the grid line is. The responsibility of the grid line is to conduct current, and from the aspect of resistivity analysis, the thinner the grid line is, the smaller the conductive cross-sectional area is, and the larger the resistance loss is. The core of the primary and secondary gate designs is thus a balance between light shielding and electrical conduction, as is the need for solder strips that subsequently make electrical contact with the gate lines. In addition, conventionally, alloying of the solder ribbon with the grid line is generally carried out by radiating heat from the top of the solder ribbon toward the battery cell using a temperature 20 ℃ higher than the temperature of the solder ribbon, so that the high melting temperature of the solder ribbon requires a higher reflow temperature during soldering, which can make the battery cell susceptible to thermal warpage. Thermal warping of the battery plate may compromise the integrity of the formed solder joints, thereby affecting its performance. Thermal warpage of the battery cells may also cause various solder defects such as breakage of the battery cells, pillow effect, and cold joint.

In addition, when the connection member employs a low melting point metal as a solder, and a lamination process is employed to achieve alloying of the gate line structure with the connection member. For example, in a component lamination process, the pressure and temperature of the laminator helps the low melting point metal bond with the gate line structure. However, the melting point of the adhesive film is lower than that of the solder in the solder strip, so that in the process of welding the low-melting-point metal and the grid line structure, the solder strip is usually offset or the adhesive film overflows between the solder strip and the fine grid to cause the situation of battery piece fragmentation or cold joint and the like, thereby influencing the battery performance and causing poor contact effect between the grid line structure and the connecting part.

The embodiment of the application provides a photovoltaic module, on one hand, a layer of composite film is arranged between a connecting component and a packaging layer, the composite film covers the surface of the connecting component, the composite film comprises an adhesive layer and a barrier layer, the adhesive layer can be used for fixing the relative position between the connecting component and a battery piece, and the connecting component is prevented from being offset caused by pushing the connecting component by the packaging layer in a molten state; the barrier layer is used for blocking the molten packaging layer from flowing between the connecting part and the battery piece during lamination treatment, so that the problem of electric connection between the battery piece and the connecting part is caused, the weldability of the assembly is improved, the tensile force in the welding strip direction is improved, the welding quality of the assembly is improved, the problems of cold welding of the assembly and the like are reduced, the product quality of the assembly is improved, the abnormality such as repair in the assembly manufacturing process is reduced, and the productivity of the assembly is greatly improved. On the other hand, the glass transition temperature of at least one of the adhesive layer and the barrier layer is larger than that of the packaging layer, and the packaging layer is in a molten state in the lamination process, but one of the adhesive layer and the barrier layer is in a relatively compact solid state, so that the molten adhesive film can be prevented from flowing between the grid line structure and the connecting part. In addition, the adhesive layer and the barrier layer can also be used as a part of the packaging layer, so that the thickness of an adhesive film on the surface of the connecting component is reduced, and the connecting component has the risk of penetrating through the packaging layer; the composite film can also be used to insulate moisture to improve the performance of the gate line structure.

Embodiments of the present application will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments.

Fig. 1 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present application; FIG. 2 is a schematic cross-sectional view of the structure of FIG. 1 along the section c ₁-c₂; FIG. 3 is a schematic view of a first cross-sectional structure of FIG. 1 along the section a ₁-a₂; fig. 4 is a schematic view of a first structure of a composite film in a photovoltaic module according to an embodiment of the present application; FIG. 5 is a schematic view of a second cross-sectional structure taken along the line a ₁-a₂ in FIG. 1; fig. 6 is a schematic view of a second structure of a composite film in a photovoltaic module according to an embodiment of the present application; FIG. 7 is a schematic view of a third cross-sectional structure taken along the line a ₁-a₂ in FIG. 1; fig. 8 is a schematic view of a third structure of a composite film in a photovoltaic module according to an embodiment of the present application; fig. 9 is a schematic diagram of a second structure of a photovoltaic module according to an embodiment of the present application; FIG. 10 is a schematic cross-sectional view of the structure of FIG. 9 along the section c ₁-c₂; fig. 11 is a schematic view of a third structure of a photovoltaic module according to an embodiment of the present application; fig. 12 is a schematic view of a fourth structure of a photovoltaic module according to an embodiment of the present application; fig. 13 is a schematic cross-sectional view of fig. 12 along the section b ₁-b₂.

The encapsulation layer and the cover plate of the photovoltaic module in fig. 1, 9, 11 and 12 are not shown, or the encapsulation layer and the cover plate are in a perspective state, so as to show and explain the positions and the connection relations between the battery pieces and the connection parts. The cross-sectional views in fig. 3, 5, 7, and 13 show only the film structures on one side of the battery sheet, and the film structures on the other side of the battery sheet may be the same as or different from the film structures on the corresponding side of the battery sheet. It can be understood that the photovoltaic modules shown in fig. 3, 5, 7 and 13 are schematic structural diagrams in which lamination treatment is not performed, that is, gaps between the battery pieces are not filled with the encapsulation layer, and the connection members and the grid line structure are not alloyed. After the photovoltaic module in the above figure is laminated, the morphology of the composite film may be changed, and the embodiment of the present application is not limited to the specific morphology, but the composite film still covers the surface of the connection component.

Referring to fig. 1 to 13, according to some embodiments of the present application, there is provided a photovoltaic module including: a plurality of battery cells 10, each battery cell 10 including a grid line structure 101 arranged at intervals along a first direction X; a plurality of connection members 11 arranged at intervals along the second direction Y, the connection members 11 being positioned on the surface of the battery cell 10 and the surface of the gate line structure 101, the connection members 11 being electrically connected to adjacent battery cells 10, respectively; a plurality of composite films 12, the composite films 12 covering the surfaces of the connection members 11, and both sides of the composite films 12 covering the surfaces of the battery cells 10 in the second direction Y; the composite film 12 comprises an adhesive layer 121 and a barrier layer 122, the adhesive layer 121 being located between the barrier layer 122 and the connecting member 11; an encapsulation layer 13, the encapsulation layer 13 covering the surface of the composite film 12; wherein, the glass transition temperature of at least one of the adhesive layer 121 and the barrier layer 122 is greater than the glass transition temperature of the encapsulation layer 13; cover plate 14, cover plate 14 is located the encapsulation layer 13 side that is away from battery piece 10.

In some embodiments, the battery sheet 10 includes any one of, but is not limited to, a PERC cell, a PERT cell (PASSIVATED EMITTER AND REAR Totally-diffused cell, passivated emitter back surface full diffusion cell), a TOPCon cell (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact cell), a HIT/HJT cell (Heterojunction Technology, heterojunction cell). In some embodiments, the cell sheet 10 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-compound solar cell, which may be specifically a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenium solar cell, or a perovskite solar cell.

In some embodiments, the battery 10 is a full back electrode contact crystalline silicon solar cell (INTERDIGITATED BACK CONTACT, IBC), where the IBC battery refers to a back junction back contact solar cell structure in which positive and negative metal electrodes are arranged on the back surface of the battery in an interdigital manner, the PN junction and the electrodes thereof are located on the back surface of the battery, that is, the electrodes of the emitter region and the base region of the IBC battery are all located on the back surface, and the front surface is not shielded by a grid line, so that the photoelectric conversion performance of the battery can be improved, and each film structure of one side of the battery 10 in the cross-sectional view shown in the drawing is different from each film structure of the other side of the battery 10, where each film structure of the battery 10 includes a packaging layer 13 and a cover plate 14.

The battery sheet 10 is a whole battery or a sliced battery. A sliced cell refers to a cell sheet formed by cutting a complete whole cell. The cutting process comprises the following steps: laser grooving+cutting (LINEAR SPECTRAL Clustering, LSC) process and thermal stress cell separation (TMC) process. In some embodiments, the sliced cells are half-cells, which may also be understood as half-sliced cells or half-cells. The half-cell assembly functions to increase the generated power by reducing the resistance loss. From ohm's law, solar cell interconnect electrical losses are proportional to the square of the current magnitude. After the battery is cut into two halves, the current is reduced by half, and the electric loss is reduced to one quarter of the full-size battery loss. The increase in the number of cells also correspondingly increases the number of cell gaps that help to boost the short circuit current through reflection from the back plate of the assembly. In addition, cutting the half cell assembly can optimize the width of the cell solder strip, which conventionally requires an optimized balance between increasing the solder strip width to reduce electrical losses and decreasing the solder strip width to reduce shading losses. And the half-cut battery assembly reduces battery loss, so that the width of the welding strip can be set thinner to reduce shading loss, and the battery efficiency and the power generation power consumption are improved. In some embodiments, the sliced cell may be a three-slice cell, a 4-slice cell, an 8-slice cell, or the like.

In some embodiments, the photovoltaic module includes at least two cells 10, at least two cells 10 are connected in series or parallel by a connecting member 11 to form a cell string, and a cell gap is formed between adjacent cells 10 to achieve electrical insulation between different cells 10.

In some embodiments, the grid line structure 101 is used to collect photo-generated current within the solar cell body and lead to the outside of the cell 10. The battery piece comprises a main grid line and an auxiliary grid line, the auxiliary grid line is intersected with the extending direction of the main grid line, the auxiliary grid line is used for collecting the current of the substrate, and the main grid line is used for summarizing the current of the auxiliary grid line and transmitting the current to the welding strip. In some embodiments, the grid line structure 101 is an auxiliary grid line, which may also be referred to as an auxiliary grid line, where the auxiliary grid line is used for guiding current, and the battery piece 10 is designed without a main grid, so as to shorten a carrier transport path and reduce series resistance, further increase the front light receiving area, increase the power of the assembly, and facilitate increasing the short-circuit current, so that the usage amount of silver paste printed on the grid line is reduced to reduce the production cost.

In some embodiments, the gate line structure 101 includes a first electrode 111 and a second electrode 112. The first surface of the battery sheet 10 has a first electrode 111, and the opposite side to the first surface, i.e., the second surface has a second electrode 112, the first electrode 111 is one of a positive electrode or a negative electrode, and the second electrode 112 is the other of the positive electrode or the negative electrode. The connection member 11 connects the first electrode 111 of any one of the battery cells 10 and the second electrode 112 of the adjacent battery cell 10.

In some embodiments, referring to fig. 1 and 2, the first surfaces of the battery plates 10 are all facing the same side, the second surfaces of the battery plates 10 are all facing the same side, or the first electrodes 111 of all the battery plates are facing the same side, and the second electrodes 112 of all the battery plates are facing the same side, then the connecting members 11 need to naturally extend from the first surfaces of the battery plates to the second surfaces of the adjacent battery plates, so that the connecting members 11 connect the first electrodes 111 and the second electrodes 112 of the adjacent battery plates 10.

In some embodiments, referring to fig. 9 and 10, the battery cells 10 are sequentially arranged in the order of the first surface, the second surface, the first surface, and the second surface, the connection member 11 is not bent, and the connection member 11 directly connects the first electrode 111 and the second electrode 112 of the battery cell 10 adjacent thereto.

In some embodiments, the connection members 11 are solder strips for interconnecting the battery cells 10 and converging current transmission to elements external to the photovoltaic module. The solder strips include a bus solder strip for connecting the photovoltaic cell string and the junction box, and an interconnect solder strip for connecting between the battery cells 10 and the battery cells 10.

In some embodiments, the connection part 11 is a core-spun structure, and the connection part 11 includes a conductive layer and a solder layer coating the surface of the conductive layer. The conductive layer is the main conductive transport layer of the connection member 11, and thus the lower the resistivity of the conductive layer is, the smaller the electrical loss of the connection member 11 is, and the better the battery efficiency and the generated power are. The conductive layer is made of conductive materials with better conductivity such as copper, nickel, gold, silver and the like or alloy materials with low resistivity.

In some embodiments, the welding layer may be plated on the surface of the conductive layer or coated on the surface of the conductive layer, and specifically, the source material of the welding layer may be uniformly coated around the conductive layer according to a certain component proportion and thickness by using a special process such as electroplating, vacuum deposition, spraying or hot dip coating. The welding layer mainly aims to enable the connecting part 11 to meet the weldability, and the connecting part 11 is firmly welded on the grid line structure 101 of the battery piece 10 to play a role in good current diversion.

In some embodiments, the material of the solder layer is a metallic or alloy material having a lower melting point than the conductive layer, such as a tin alloy, which may include a tin-zinc alloy, a tin-bismuth alloy, or a tin-indium alloy. And the tin is used for welding a welding material, has a low melting point, has good affinity with metals such as copper and the like, and has good welding fastness. The lead in the tin-lead alloy can reduce the melting point of the welding strip, and the tin and the lead can form a eutectic point with the melting point of 183 ℃, so that the tin-lead alloy has good welding performance and usability. The disclosed embodiments can reduce the melting point temperature and surface tension by replacing lead with other metallic elements or adding other elements, such as bismuth, to the tin-lead alloy. The melting point of the tin-bismuth alloy can be reduced to 139 ℃ to meet the requirement of low-temperature welding.

In some embodiments, the solder layer has a flux therein, which refers to a chemical substance that aids and facilitates the soldering process during the soldering process, while having a protective effect, preventing oxidation reactions. The flux includes an inorganic flux, an organic flux, and a resin flux. It will be appreciated that the flux has a melting point lower than that of the solder layer and increases the fluidity of the molten solder layer to provide good alloying of the solder layer with the gate line structure 101.

In some embodiments, the cross-section along the second direction Y of the connection member 11 is circular in cross-sectional shape, and the circular solder strip is free from orientation problems and alignment problems, and is easier to mass produce. In some embodiments, the cross-sectional shape of the connection member 11 may be triangular or any other shape to increase the contact area of the solder strip with the gate line structure and to reduce the problem of misalignment of the connection member 11 with the gate line structure 101.

In some embodiments, the surface of the connection member 11 remote from the battery cell 10 has a light reflecting layer, and the light reflecting layer is located on the outer side of the solder layer remote from the conductive layer and the battery cell 10. The light reflecting layer serves to improve electrical loss due to the shielding area of the connection member 11 to the battery cell 10. In some embodiments, the outer surface of the solder layer has reflective grooves, which are concave grooves or grooves facing the conductive layer from the solder layer, and sunlight is reflected onto the battery cells 10 through the sidewalls of the reflective grooves, thereby improving the utilization rate of sunlight.

In some embodiments, composite film 12 refers to a film layer composed of two materials or more than two materials in a certain ratio and a certain morphology. Referring to fig. 1 and 3, the adjacent composite films 12 are not in contact with each other, the composite films 12 cover the surface of the connection member 11 and the surfaces of the battery cells 10 on the opposite sides of the connection member 11 in the second direction Y, and the composite films 12 are also positioned on the opposite sides of the connection member 11. In this way, the composite film 12 completely encapsulates the contact interface between the connection member 11 and the grid line structure 101, so as to prevent the molten encapsulation layer from penetrating into the contact interface between the grid line structure 101 and the connection member 11 in the lamination process, thereby affecting the contact performance between the connection member 11 and the grid line structure 101 and further affecting the yield of the photovoltaic module. Moreover, the adjacent composite films 12 are not contacted, on one hand, the shielding area of the non-transparent composite film 12 to the battery piece 10 can be reduced, so that the optical loss is reduced; on the other hand, the softness and permeability of the composite film 12 may not be the same as those of the encapsulation layer 13, so that the adjacent composite films 12 are not contacted, and defects (gaps or air intervals) in the photovoltaic module are reduced as much as possible, so that air is discharged as much as possible, and the situation that the encapsulation layer 13 or the composite film 12 is separated from the surface of the cell 10 due to heating of the air, and then the cell 10 is corroded by moisture is avoided.

In addition, the composite film 12 can also be used as a part of the packaging layer 13 after the subsequent lamination treatment, which is beneficial to reducing the risk that the thickness of the adhesive film on the surface of the connecting component 11 is thinner and the connecting component 11 pierces the packaging layer 13, and the thickness of the packaging layer 13 can be correspondingly reduced because the composite film 12 is used as a part of the packaging layer 13, thereby reducing the preparation cost of the packaging layer 13. When the thickness of the encapsulation layer 13 is reduced, the absorption of light by the encapsulation layer 13 itself is reduced, and sunlight received by the battery piece 10 is increased, which is beneficial to improving the photoelectric conversion efficiency of the battery piece 10. The composite film 12 may also be used to insulate moisture to improve the performance of the gate line structure 101.

In some embodiments, the spacing between adjacent composite films 12 is less than 5/6 of the spacing of adjacent connecting members 11. In this way, the area of the composite film 12 covering the connection member 11 is large and does not provide a large shielding area for the surface of the battery sheet 10, thereby reducing the manufacturing cost and the shielding area of the battery sheet 10.

It should be noted that the above-mentioned distance between adjacent composite films 12 refers to a distance between opposite sides of adjacent composite films 12, or may be regarded as a distance between edges of the composite films 12. The pitch of adjacent connection members 11 refers to the distance between the edges of the connection members 11. It can be pushed out that the composite film 12 is still located on the surface of the battery piece 10 from 5/6 of the distance between the adjacent composite films 12 being smaller than the distance between the adjacent connection members 11, so that the contact structure of the connection members 11 and the grid line structure 101 is tightly protected.

In some embodiments, referring to fig. 11, in the second direction Y, adjacent composite films 12 are continuous film layers, i.e., contact between adjacent composite films 12 and are the same original film layer. In this way, in the step of preparing the photovoltaic module corresponding to the laying of the composite film 12, the alignment problem of the composite film 12 and the connecting member 11 may not be considered, so that the preparation difficulty of the photovoltaic module is reduced to a certain extent.

It should be noted that, along the second direction Y, the side of the composite film 12 near the edge of the battery sheet 10 may be sufficient to cover the surface of the connection member 11 closest to the edge of the battery sheet, or the first distance between the edge of the composite film 12 and the opposite edge of the battery sheet may be smaller than the second distance between the edge of the connection member 11 and the opposite edge of the battery sheet, and the specific value and the range of the first distance between the edge of the composite film 12 and the opposite edge of the battery sheet is not limited to be smaller than the second distance between the edge of the connection member 11 and the opposite edge of the battery sheet.

In some embodiments, the composite film 12 is an integrally formed structure, so that there is no offset and defects between interfaces between the adhesive layer 121 and the barrier layer 122 in the step prior to the lamination process, improving the overall performance of the composite film 12.

In some embodiments, along the first direction X, the composite film 12 covers the connection members 11 on the plurality of battery cells 10, that is, the composite film 12 is further located in the battery gap between the adjacent battery cells 10, so as to achieve the overall wrapping of the connection members 11 by the composite film 12, and prevent the molten encapsulation layer 13 from penetrating from the edges of the battery cells 10 between the grid line structure 101 and the connection members 11.

It will be appreciated that, for one cell, the length of the composite film 12 is greater than the length of the cell 10 and the length of the composite film 12 is less than or equal to the length of the connection member 11 in the first direction X, so as to ensure that the molten encapsulation layer 13 does not penetrate between the grid line structure 101 and the connection member 11 from the edge of the cell 10 and the manufacturing cost of the composite film 12 is also low.

In some embodiments, the adhesive layer 121 refers to a film layer composed of a material having tackiness for fixing the connection member 11 to the battery cell 10, preventing the connection member 11 from being deviated in a step before the lamination process; and, the pushing of the molten encapsulation layer against the connection member 11 during the lamination process is prevented from causing the connection member 11 to shift.

In some embodiments, the material of adhesive layer 121 includes EVA (ethylene vinyl acetate), acrylic or PE (polyethylene), or the like. When the material of the adhesive layer 121 is EVA, the adhesive layer 121 may be used as a barrier layer for preventing the penetration of the molten encapsulation layer 13 into the connection member 11 and the gate line structure 101 and a protective layer for preventing moisture while ensuring a certain viscosity to fix the connection member 11 to the battery cell 10. The cost of EVA production is low, and the cost of composite membrane 12 production is correspondingly reduced.

When the material of the adhesive layer 121 is acrylic esters, the acrylic esters have certain transparency, so that the optical loss of the battery piece 10 is reduced; the acrylic ester can be directly cured in an environment with low temperature, the curing speed is high, the thermal stress on the battery piece 10 is reduced, the risk of breakage of the battery piece 10 is reduced, and the yield of the photovoltaic module is improved; the acrylic acid ester has good water resistance and can be used for preventing the connecting component 11 from being damaged by water vapor.

In some embodiments, the thickness of adhesive layer 121 ranges from 10 μm to 150 μm. The thickness of the adhesive layer 121 may range from 10 μm to 130 μm, from 10 μm to 109 μm, from 10 μm to 85 μm, from 10 μm to 139 μm, from 30 μm to 150 μm, from 68 μm to 150 μm, from 102 μm to 150 μm, or from 49 μm to 124 μm. The thickness of the adhesive layer 121 may be 15 μm, 29 μm, 65 μm, 89 μm, 106 μm, 134 μm or 150 μm in particular. When the thickness of the adhesive layer 121 is within the above range, the adhesive layer 121 has a sufficient thickness for fixing the connection member 11 on the surface of the battery sheet 10 without being deviated in the subsequent step, and the adhesive layer 121 does not occupy more thickness of the photovoltaic module, so as to reduce the thickness of the photovoltaic module to a certain extent, thereby achieving high integration of the photovoltaic module.

In some embodiments, the glass transition temperature of the adhesive layer 121 ranges from-55 ℃ to 0 ℃, and the glass transition temperature of the adhesive layer 121 is in a range that ensures that the adhesive layer 121 can be in a high-elastic state during normal temperature, so that the adhesive layer 121 can have a certain viscosity for fixing the connecting component 11 to the composite film 12 and preventing the connecting component 11 from being deviated, and also for preventing moisture and a molten encapsulation layer from invading from a contact interface between the battery sheet 10 and the composite film 12; secondly, some modifier with higher glass transition temperature can be added into the pure polymer material with viscosity in the adhesive layer 121, so that the glass transition temperature of the adhesive layer 121 is greater than the glass transition temperature of the encapsulation layer 13, when the encapsulation layer is in a molten state, the adhesive layer 121 is not molten and is in a glass state, and the molten encapsulation layer cannot be immersed between the connection part 11 and the grid line structure 101 through the adhesive layer 121. The glass transition temperature of the adhesive layer 121 ranges from-58 to-1 deg.c, from-48 to-12 deg.c, from-31 to-1 deg.c, or from-38 to-15 deg.c.

The glass transition temperature (Tg) refers to a temperature corresponding to the transition from a glass state to a highly elastic state (rubbery state). At lower temperature, the material is in a rigid solid state, similar to glass, and can only generate very small deformation under the action of external force, and the state is a glass state: when the temperature continues to rise to a certain range, the deformation of the material is obviously increased, and the deformation is relatively stable in a certain subsequent temperature interval, wherein the state is a high-elasticity state, the deformation amount is gradually increased when the temperature continues to rise, the material gradually becomes viscous fluid, and the deformation cannot be recovered at the moment, and the state is a viscous state. The glass transition temperature can be measured by a DSC (DIFFERENTIAL SCANNING calorimeter ) instrument.

In some embodiments, the barrier layer 122 refers to a film layer having a certain isolation property for preventing the encapsulation layer 13 in a molten state from penetrating between the connection part 11 and the gate line structure 101 and isolating moisture. The material of the barrier layer 122 includes PET (polyethylene terephthalate), POE (polyolefin), liquid silicone, or PVB (polyvinyl butyral). POE is a nonpolar material, has excellent water vapor barrier capability and ion barrier capability, and the water vapor transmittance is only about 1/8 of that of the EVA adhesive film; because the molecular chain structure is stable, acidic substances are not generated by decomposition in the aging process, and the aging resistance is excellent; PVB has good water resistance, resistance and oil resistance, PVB resin has good optical definition, the refractive index of the PVB resin is similar to that of glass, an image picked up by laminated glass cannot generate optical distortion and double phases, and the loss of incident light contacted with the surface of a photovoltaic module can be reduced. PVB can remain undeformed over a wide temperature range; has the combination of rigidity and flexibility and excellent shock resistance; has excellent adhesion efficiency with various glass surfaces. The liquid silica gel has excellent tearing resistance, rebound resilience, yellowing resistance, heat stability, heat resistance, ageing resistance and the like, and meanwhile, the liquid silica gel has moderate viscosity, convenient operation and high transparency.

In some embodiments, the thickness of the barrier layer 122 ranges from 20 μm to 50 μm. The thickness of the barrier layer 122 may range from 20 μm to 45 μm, from 20 μm to 38 μm, from 20 μm to 31 μm, from 25 μm to 50 μm, from 36 μm to 50 μm, from 23 μm to 48 μm, from 31 μm to 42 μm, or from 30 μm to 40 μm. The thickness of the barrier layer 122 may be in particular 23 μm, 26 μm, 31 μm, 36 μm, 39 μm, 45 μm or 50 μm. When the thickness of the barrier layer 122 is within the above range, the barrier layer 122 has a sufficient thickness for preventing moisture and a molten encapsulation layer, and the barrier layer 122 does not occupy more thickness of the photovoltaic module, so as to reduce the thickness of the photovoltaic module to a certain extent, and achieve high integration of the photovoltaic module. In addition, the blocking layer 122 absorbs less light, which is beneficial to improving the photoelectric conversion efficiency of the battery plate.

In some embodiments, the ratio of the thickness of adhesive layer 121 to the thickness of barrier layer 122 is 1/5 to 75. The ratio of the thickness of the adhesive layer 121 to the thickness of the barrier layer 122 may be 1/5 to 50, 1/5 to 35, 1/5 to 10, 1to 75, 18 to 75, 35 to 75, 25 to 51, or 39 to 73. The ratio of the thickness of the adhesive layer 121 to the thickness of the barrier layer 122 may be, in particular, 1.3, 10.2, 19.8, 28, 37, 52, 58, 67.5 or 75. The thickness of the adhesive layer 121 and the thickness of the barrier layer 122 are within the above range, the thickness of the adhesive layer 121 is larger, the proportion of the barrier layer 122 is smaller, the softness of the adhesive layer 121 is greater than that of the barrier layer 122, the proportion of the adhesive layer 121 is more, the composite film 12 is more easily close to the connecting member 11, and the smaller the gap between the composite film 12 and the connecting member 11 is; the greater thickness of the barrier layer 122 provides better insulation against moisture and the like from entering the battery cell 10. Wherein, the softness degree refers to the flexibility of the film layer or the fitting degree between the film layer and the connecting member.

In some embodiments, at the same preset temperature, the viscosity of the adhesive layer 121 is greater than that of the barrier layer 122, so that the adhesive layer 121 may have sufficient viscosity to ensure the adhesion performance between the connection member 11 and the battery sheet 10, so that the space formed by the composite film 12 and the battery sheet 10 has a certain compactness for preventing the intrusion of the encapsulation layer 13.

In some embodiments, the viscosity number of the adhesive layer 121 before lamination curing is in the range 8000-20000 mPa-s. The viscosity range of the adhesive layer 121 is firstly used for enabling the adhesive layer 121 to have certain fluidity and poor compactness before solidification, and air can be discharged to prevent the adhesive layer 121 from being ejected by heat in the follow-up process so that the molten adhesive film flows between the connecting component and the grid line structure. The viscosity of the adhesive layer 121 may increase to 10000-30000mpa·s after lamination and curing, so that there is sufficient connection force between the connection member 11 and the surface of the battery sheet 10, and the connection member 11 is provided with protection against infiltration of the encapsulation layer 13 during lamination and erosion of moisture in the assembly during long-term use.

In some embodiments, the material of barrier layer 122 is different from the material of adhesive layer 121; the water permeability of the material of the barrier layer 122 ranges from 2 to 4g/m ². The water permeability of the barrier layer 122 ranges from 2 to 3.3g/m ²、2～2.8g/m²、2～2.64g/m²、2.35～3.89g/m²、2.8～3.96g/m² or from 2.6 to 3.35g/m ², and the water permeability of the barrier layer 122 may specifically be 2.05g/m ²、2.45g/m²、2.98g/m²、3.17g/m²、3.56g/m² or 4g/m ². The barrier layer 122 within the above range indicates that the barrier layer 122 has a good barrier property, i.e., a water vapor barrier property, which refers to the barrier effect of the packaging material against the permeation of liquid, water vapor, etc. The barrier property is better, and the molten encapsulation layer cannot pass through the barrier layer 122, and small molecules, moisture and the like of the permeated encapsulation layer cannot pass through, so as to realize better protection of the connecting component 11.

The water vapor permeability (water vapor permeability) includes both the water vapor permeability and the water vapor permeability coefficient, and the water vapor permeability indicates the weight of the water vapor permeable material under a certain temperature and humidity condition for a certain period of time. The water vapor permeability means the amount of water vapor transmitted through a unit thickness and a unit area of a sample per unit time under a unit water vapor pressure difference in a predetermined temperature and relative humidity environment.

In some embodiments, the glass transition temperature of the barrier layer 122 ranges from 100 to 200 ℃, and the glass transition temperature of the barrier layer 122 ranges from 130 to 200 ℃, 153 to 200 ℃, 189 to 200 ℃, or 150 to 184 ℃. The glass transition temperature range of the barrier layer 122 is used to ensure that the glass transition temperature of the barrier layer 122 is greater than the glass transition temperature of the encapsulation layer 13, and when the encapsulation layer is in a molten state, the barrier layer 122 is not yet molten and is in a glass state, and the encapsulation layer in the molten state cannot be immersed between the connection member 11 and the gate line structure 101 through the barrier layer 122.

In some embodiments, barrier layer 122 barrier properties may be increased by adding a plasticizer within barrier layer 122. The embodiment of the application can also increase the connection effect between the barrier layer 122 and the battery piece by adding some small molecules with viscosity into the barrier layer 122, so as to avoid the offset of the connection part and the invasion of the packaging layer. Embodiments of the present application may further increase the glass transition temperature of barrier layer 122 by incorporating some small molecules with high glass transition temperatures into barrier layer 122.

In some embodiments, referring to fig. 5 and 6, the barrier layer 122 surrounds a portion of the adhesive layer 121, and then the barrier layer 122 encapsulates the adhesive layer 121, with a greater proportion of the barrier layer 122 serving to prevent the ingress of the encapsulation layer 13 in the molten state and moisture for the contact interface between the battery sheet 10 and the composite film 12.

In some embodiments, referring to fig. 7 and 8, the adhesive layer 121 surrounds a portion of the barrier layer 122, and the barrier layer 122 is not in contact with the battery piece 10, so that the contact surface between the adhesive layer 121 and the battery piece 10 is more, the better the adhesion effect between the composite film 12 and the battery piece 10 is, and the lower the probability of misalignment between the battery piece 10 and the connection member 11 is. In addition, the compactness of the adhesive layer 121 is worse than that of the barrier layer 122, so that air between the adhesive layer 121, the battery piece 10 and the connecting part 11 can be discharged through the adhesive layer 121, and the situation that air exists in a space under the wrapping of the composite film 12 and pushes the composite film 12 open, and even the composite film 12 is separated from the battery piece 10 in the subsequent lamination treatment or any heat treatment process is prevented.

The values illustrate that, in the wrapping structure formed in the morphology of the photovoltaic module composite film 12 in fig. 6, the width of the barrier layer 122 on the side surface of the adhesive layer 121 should be set according to the actual situation, so that the contact interface between the adhesive layer 121 and the battery piece 10 needs to be ensured, and the proportion of the contact interface should not be too small, so that the effect of the adhesive layer 121 is fully exerted.

In some embodiments, the side of the composite film 12 away from the cell 10 has a reflective layer or a light-emitting groove to increase the solar light utilization and improve the photoelectric conversion efficiency of the cell.

In some embodiments, referring to fig. 12 and 13, the photovoltaic module further comprises: the glue points 102, the glue points 102 are positioned on the surface of the battery piece 10 and between the adjacent grid line structures 101; the connecting member 11 is located on the glue sites 102.

In some embodiments, the glue material used for manufacturing the glue dots 102 is preferably transparent glue, so that the area of the surface of the solar cell capable of absorbing light is ensured as much as possible, and the decrease of the area of the surface of the solar cell 10 capable of absorbing light due to the arrangement of the glue dots 102 is avoided, thereby affecting the efficiency of the solar cell.

In some embodiments, the number of glue sites 102 is 2 to 20 for one connecting part 11. The spacing between adjacent glue sites 102 is 5mm to 100mm. The number or the interval of the glue points 102 ensures that the fixing effect of the connecting part 11 and the battery piece 10 is better on one hand, so that the connecting part 11 cannot deviate before and during the lamination treatment; on the other hand, the number of glue sites 102 also gives optical loss to the battery cell 10 to obtain more electrical performance.

It can be understood that the cell 10 in the above photovoltaic module is a cell designed without a main grid, that is, the surface of the cell is not provided with the main grid, but is directly alloyed with the fine grid through the connecting component 11 to realize current collection on the surface of the cell. However, the scheme of the composite film in the photovoltaic module provided by the embodiment of the application is also suitable for a conventional battery piece with a main grid, and is used for improving the contact performance of the main grid and a connecting part so as to improve the yield of the photovoltaic module.

In some embodiments, the encapsulation layer 13 includes a first encapsulation layer covering one of the front or back sides of the battery sheet 10 and a second encapsulation layer covering the other of the front or back sides of the battery sheet 10, and specifically, at least one of the first or second encapsulation layers may be an organic encapsulation adhesive film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene co-elastomer (POE) adhesive film, or a polyvinyl butyral (PVB) adhesive film.

In some embodiments, the melting point of the encapsulation layer 13 is less than the lamination temperature during the lamination process, the encapsulation layer 13 is a film layer formed by the macromolecules in a cross-linked state formed by the small molecules in the adhesive film combined with each other due to the initiator in the encapsulation layer 13 when the adhesive film is in a molten state at the temperature of the laminator.

In some embodiments, the melting point of the encapsulation layer 13 and the melting point of the connection component 11 may be set according to practical requirements. When the melting point of the encapsulation layer 13 is greater than that of the connection part 11, the connection part 11 can be alloyed before the encapsulation layer 13 is in a molten state, so that the molten adhesive film can be effectively prevented from being immersed into the grid line structure 101 and the connection part 11 and pushing the connection part 11 to deviate. When the melting point of the encapsulation layer 13 is smaller than that of the connection member 11, the lamination temperature can be set to be lower, so that the thermal stress to which the battery piece is subjected is improved, and the yield of the photovoltaic module is improved.

In some embodiments, at least one of the adhesive layer 121 and the barrier layer 122 has a glass transition temperature greater than that of the encapsulation layer, and when the encapsulation layer 13 is in a molten state, one of the adhesive layer and the barrier layer still maintains a good morphology, so as to effectively avoid the molten state adhesive film from immersing into the gate line structure 101 and the connection member 11 and pushing the connection member 11 to shift.

In some embodiments, the glass transition temperature of the encapsulation layer is-70 to-10 ℃, and the glass transition temperature of the encapsulation layer is used to ensure that the encapsulation layer can be in a molten state during the lamination process to fill various gaps of the photovoltaic module and improve the yield of the photovoltaic module.

In some embodiments, the cover 14 may be a glass cover, a plastic cover, or the like having a light-transmitting function. Specifically, the surface of the cover plate 14 facing the encapsulation layer 13 may be a concave-convex surface, thereby increasing the utilization rate of incident light. The cover 14 includes a first cover plate opposite the first encapsulation layer and a second cover plate opposite the second encapsulation layer.

According to the photovoltaic module provided by the embodiment of the application, on one hand, a layer of composite film 12 is arranged between the connecting part 11 and the packaging layer 13, the composite film 12 covers the surface of the connecting part 11, the composite film 12 comprises an adhesive layer 121 and a barrier layer 122, the adhesive layer 121 can be used for fixing the relative position between the connecting part 11 and the cell 10, and the packaging layer 13 in a molten state is prevented from pushing the connecting part 11 to cause the deflection of the connecting part 11; the barrier layer 122 is used for blocking the molten packaging layer 13 from flowing between the connecting component 11 and the battery piece 10 during lamination, thereby causing the problem of electrical connection between the battery piece 10 and the connecting component 11, improving the weldability of the component, improving the tensile force in the welding strip direction, improving the welding quality of the component, reducing the problems of false welding of the component, improving the product quality of the component, reducing the abnormality such as repair in the component manufacturing process, and greatly improving the productivity of the component. On the other hand, at least one of the adhesive layer 121 and the barrier layer 122 has a glass transition temperature greater than that of the encapsulation layer 13, and the encapsulation layer 131 is in a molten state during the lamination process, but one of the adhesive layer 121 and the barrier layer 122 is in a more compact solid state, so that the molten adhesive film can be prevented from flowing between the gate line structure 101 and the connection member 11. In addition, the adhesive layer 121 and the barrier layer 122 can also be used as a part of the encapsulation layer 13, so that on one hand, the encapsulation layer 13 on the surface of the connecting component 11 is prevented from being thinner, and the connecting component 11 has the risk of penetrating through the encapsulation layer 13; the composite film 12 may also be used to insulate moisture to improve the performance of the gate line structure.

Accordingly, according to some embodiments of the present application, another aspect of the present application further provides a method for manufacturing a photovoltaic module, which is used for manufacturing the photovoltaic module provided in the foregoing embodiments, where the elements are the same as or corresponding to those in the foregoing embodiments, and are not repeated herein.

In some embodiments, a method of making a photovoltaic module includes:

S1, providing a plurality of battery pieces, wherein each battery piece comprises grid line structures which are arranged at intervals along a first direction.

S2, providing a plurality of connecting components which are arranged at intervals along a second direction, wherein the connecting components are positioned on the surfaces of the battery pieces and are electrically connected with the adjacent battery pieces;

S3, providing a plurality of composite films, wherein the composite films cover the surfaces of the connecting parts, and the two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a barrier layer, and the adhesive layer is positioned between the barrier layer and the connecting part;

S4, providing a packaging layer, wherein the packaging layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer;

S5, providing a cover plate, wherein the cover plate is positioned on one side of the packaging layer far away from the battery piece;

S6, laminating treatment is carried out.

In some embodiments, the process for preparing the composite film comprises: uniformly mixing the raw materials of the adhesive layer according to the proportion, extruding the mixture through extrusion equipment to form a first raw material, uniformly mixing the raw materials of the barrier layer according to the proportion, and extruding the mixture through extrusion equipment to form a second raw material; pouring one of the first raw material or the second raw material into forming equipment according to the proportion to form an initial film; and (3) co-extrusion compounding, namely pouring the other one of the first raw material and the second raw material into forming equipment, and forming the composite film through screw extrusion compounding.

In some embodiments, the initial film is composed of a second starting material, and the process of forming the initial film further comprises: extruding and grooving the initial film through a die, and forming a containing groove in the middle of the initial film; in the coextrusion compounding, a first raw material in a semi-fluid state is placed in a containing groove of an initial film in a semi-fluid state, the raw material is extruded and compounded through a screw, extruded through a forming die, sheet-shaped cast onto the roller surface of a cooling roller which rotates stably, a film sheet is cooled and shaped on the cooling roller, and then the film sheet is pulled and cut into edges to roll the product.

In some embodiments, between S1 and S2 further comprises: paving glue points, wherein the glue points are positioned on the surfaces of the battery pieces and between adjacent grid line structures; the connecting part is positioned on the glue point. After the connection part is laid, the curing of the glue points is also involved, so that the viscosity of the glue points is increased, and the curing capability between the connection part and the battery piece is improved. For example, before curing, the viscosity of the glue sites is 8000 mPas and after curing, the viscosity of the glue sites is 10000 mPas.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the application and that various changes in form and details may be made therein without departing from the spirit and scope of the application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, and the scope of the application should be assessed accordingly to that of the appended claims.

Claims

1. A photovoltaic module, comprising:

Each battery piece comprises grid line structures which are arranged at intervals along a first direction;

The connecting parts are arranged at intervals along the second direction and are positioned on the surface of the battery piece and the surface of the grid line structure, and the connecting parts are respectively and electrically connected with the adjacent battery pieces;

the composite films cover the surfaces of the connecting parts, and two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a barrier layer, wherein the adhesive layer is positioned between the barrier layer and the connecting part; the spacing between adjacent composite films is less than 5/6 of the spacing between adjacent connecting components; the packaging layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer such that at least one of the adhesive layer and the barrier layer can prevent the encapsulation layer in a molten state from flowing between the gate line structure and the connection member;

and the cover plate is positioned on one side of the packaging layer away from the battery piece.

2. The photovoltaic module of claim 1, wherein the ratio of the thickness of the adhesive layer to the thickness of the barrier layer is 1/5 to 75.

3. The photovoltaic module of claim 1 or 2, wherein the barrier layer surrounds a portion of the adhesive layer.

4. The photovoltaic module of claim 1, wherein the viscosity of the adhesive layer is greater than the viscosity of the barrier layer at the same predetermined temperature.

5. The photovoltaic module of claim 1, wherein the material of the barrier layer is different from the material of the adhesive layer; the water permeability of the material of the barrier layer is in the range of 2-4 g/m ².

6. The photovoltaic module of claim 1 or 5, wherein the material of the barrier layer comprises PET, POE, liquid silicone, or PVB.

7. The photovoltaic module of claim 1, further comprising: the glue points are positioned on the surface of the battery piece and between the adjacent grid line structures; the connecting part is positioned on the glue point.

8. The photovoltaic module of claim 1, wherein the adhesive layer has a glass transition temperature in the range of-55 to 0 ℃.

9. The photovoltaic module of claim 1, wherein the barrier layer has a glass transition temperature in the range of 100 to 200 ℃.

10. A method of manufacturing a photovoltaic module, comprising:

providing a plurality of battery pieces, wherein each battery piece comprises grid line structures which are arranged at intervals along a first direction;

Providing a plurality of connecting components which are arranged at intervals along a second direction, wherein the connecting components are positioned on the surface of the battery piece and are electrically connected with the adjacent battery pieces;

Providing a plurality of composite films, wherein the composite films cover the surfaces of the connecting parts, and two sides of the composite films cover the surfaces of the battery pieces along the second direction; the composite film comprises an adhesive layer and a barrier layer, wherein the adhesive layer is positioned between the barrier layer and the connecting part; the spacing between adjacent composite films is less than 5/6 of the spacing between adjacent connecting components;

Providing an encapsulation layer, wherein the encapsulation layer covers the surface of the composite film; wherein at least one of the adhesive layer and the barrier layer has a glass transition temperature greater than that of the encapsulation layer;

Providing a cover plate, wherein the cover plate is positioned on one side of the packaging layer far away from the battery piece;

Laminating; at least one of the adhesive layer and the barrier layer may prevent the encapsulation layer in a molten state from flowing between the gate line structure and the connection member during the lamination process.

11. The method of manufacturing a photovoltaic module according to claim 10, wherein the process of manufacturing the composite film comprises: uniformly mixing the raw materials of the adhesive layer according to the proportion, extruding the mixture through extrusion equipment to form a first raw material, uniformly mixing the raw materials of the barrier layer according to the proportion, and extruding the mixture through extrusion equipment to form a second raw material;

Pouring one of the first raw material or the second raw material into forming equipment according to the proportion to form an initial film;

And (3) co-extrusion compounding, namely pouring the other one of the first raw material and the second raw material into the forming equipment, and forming the composite film through screw extrusion compounding.