Photovoltaic module and method of manufacturing same

Abstract

To provide a photovoltaic module capable of improving yield thereof and a preparation method thereof.SOLUTION: A photovoltaic module includes: a plurality of connection members which each are located on a surface of a battery cell and on a surface of a grid line structure, and electrically connected to corresponding adjacent battery cells; a plurality of composite films which each cover a surface of a respective connection member, have both sides covering a surface of a corresponding battery cell along a second direction, and include an adhesive layer and a blocking layer, the adhesive layer being located between the blocking layer and a corresponding connection member; an encapsulation layer which covers surfaces of the composite films, at least one of the adhesive layer and the blocking layer having a glass transition temperature greater than a glass transition temperature of the encapsulation layer; and a cover plate disposed on a side of the encapsulation layer away from the battery cells.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present application relate to the photovoltaic field, and more particularly to photovoltaic modules and methods for their manufacture. [Background technology]

[0002] A solar cell is a device that converts light energy directly into electrical energy through photoelectric or photochemical effects. A single cell cannot generate electricity directly. Multiple cells must be connected in series or parallel by PV ribbons and tightly sealed into a module for use. A solar cell module (also called a solar panel) is the core of a solar power generation system and is also the most important part of the system. The role of a solar cell module is to convert solar energy into electrical energy, send it to a battery for storage, and drive the operation of the equipment.

[0003] The cells are very fragile, and in order to protect the battery cells, it is generally necessary to install adhesive films and cover plates on the top and bottom of the battery module. The cover plate is generally photovoltaic glass, which cannot be directly attached to the top surface of the battery cell, and the adhesive film must play an adhesive role in it. The connection between the battery cells usually requires PV ribbons to collect current, and ordinary PV ribbons need to be alloyed between the PV ribbons and the fine grids by soldering during welding. In order to increase the battery efficiency and battery yield, the shading and conductivity between the main grid and the fine grids are usually balanced, but there are many factors that affect the yield of photovoltaic modules.

[0004] In addition, the melting point of the solder in the PV ribbon is generally high, and in the actual welding process, the welding temperature is more than 20°C higher than the solder melting point. Battery cells have a large warpage deformation during welding, so after welding, there is a high risk of hidden cracks and a high rate of debris. In particular, PERC batteries (Passivated Emitter and Rear Cell) have a large internal stress, which makes them prone to warpage and debris after welding, leading to an increase in the re-repair rate of modules and a decrease in yield. Under this background, in order to improve the welding quality, low-temperature PV ribbon and main gridless technologies have been born accordingly. However, there are still many factors that affect the module yield, such as the welding effect between the PV ribbon and the fine grid and the welding yield. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments of the present application provide a photovoltaic module and a manufacturing method thereof that are advantageous in improving at least the yield of photovoltaic modules. [Means for solving the problem]

[0006] According to some embodiments of the present application, in a first aspect of the embodiment, a photovoltaic module is provided, the photovoltaic module including: a plurality of battery cells each having a grid line structure arranged at intervals along a first direction; a plurality of connection members arranged at intervals along a second direction, the connection members being located on a surface of the battery cells and a surface of the grid line structure, the connection members being electrically connected to adjacent battery cells, respectively; a plurality of composite films covering surfaces of the connection members, both sides of the composite films covering surfaces of the battery cells along the second direction, the composite films comprising an adhesive layer and a barrier layer, the adhesive layer being located between the barrier layer and the connection members; a sealing layer covering a surface of the composite film, wherein a glass transition temperature of at least one of the adhesive layer and the barrier layer is higher than a glass transition temperature of the sealing layer; and a cover plate located on a side of the sealing layer away from the battery cells.

[0007] In some embodiments, the pitch between adjacent said composite films is less than 5 / 6 of the pitch between adjacent connecting members.

[0008] In some embodiments, the ratio of the adhesive layer thickness to the barrier layer thickness is between 1 / 5 and 75.

[0009] In some embodiments, the barrier layer surrounds a portion of the adhesive layer.

[0010] In some embodiments, along the second direction, adjacent composite films are continuous film layers.

[0011] In some embodiments, the tack of the adhesive layer is greater than the tack of the barrier layer at the same preset temperature.

[0012] In some embodiments, the barrier layer material is different from the adhesive layer material and the barrier layer material has a water permeability in the range of 2 to 4 g / m 2 It is.

[0013] In some embodiments, the barrier layer material includes PET, POE, liquid silica gel, or PVB.

[0014] In some embodiments, the battery further includes adhesive dots located on a surface of the battery cells and between adjacent gridline structures, the connecting members being located on the adhesive dots.

[0015] In some embodiments, the adhesive layer has a glass transition temperature range of -55 to 0°C.

[0016] In some embodiments, the barrier layer has a glass transition temperature range of 100-200°C.

[0017] According to some embodiments of the present disclosure, in another aspect of the present disclosure, there is provided a method for manufacturing a photovoltaic module, the method comprising: providing a plurality of battery cells, each of the battery cells including a grid line structure arranged in a spaced relationship along a first direction; providing a plurality of connection members arranged at intervals along a second direction, the connection members being located on a surface of the battery cells and electrically connected to adjacent battery cells; providing a plurality of composite films, the composite films covering a surface of the connection member, and both sides of the composite films covering a surface of the battery cell along the second direction, the composite films including an adhesive layer and a barrier layer, the adhesive layer being located between the barrier layer and the connection member; providing a sealing layer overlying a surface of the composite film, wherein a glass transition temperature of at least one of the adhesive layer and the barrier layer is greater than a glass transition temperature of the sealing layer; providing a cover plate located on a side of the sealing layer away from the battery cell; and performing a lamination process.

[0018] In some embodiments, the process for producing the composite film includes: uniformly mixing the raw materials of the adhesive layer according to a compounding ratio and extruding them through an extrusion device to form a first raw material; uniformly mixing the raw materials of the barrier layer according to a compounding ratio and extruding them through an extrusion device to form a second raw material; pouring either the first raw material or the second raw material into a molding device according to a compounding ratio to form an initial film; co-extrusion compounding; and pouring the other of the first raw material and the second raw material into the molding device and forming the composite film by screw extrusion compounding. Effect of the Invention

[0019] The technical solutions provided in the embodiments of the present application have at least the following advantages:

[0020] Between the connecting member and the sealing layer, a composite film is provided covering the surface of the connecting member, the composite film including an adhesive layer and a blocking layer, the adhesive layer is used to fix the relative position between the connecting member and the battery cell, and prevent the molten sealing layer from pressing the connecting member and causing the connection member to be displaced, and the blocking layer is used to prevent the molten sealing layer from flowing between the connecting member and the battery cell during the lamination process, thus causing problems in the electrical connection between the battery cell and the connecting member, thereby improving the weldability of the module, increasing the tensile force in the extension direction of the PV ribbon, improving the welding quality of the module, reducing problems such as cold solder connection of the module, improving the product quality of the module, reducing abnormalities such as re-repair during the module manufacturing process, and greatly improving the productivity of the module. Meanwhile, the glass transition temperature of at least one of the adhesive layer and the blocking layer is higher than the glass transition temperature of the sealing layer, and while the sealing layer is in a molten state during the lamination process, one of the adhesive layer and the blocking layer is in a relatively dense solid state. This can prevent the molten adhesive film from flowing between the grid line structure and the connecting member. In addition, the adhesive layer and the barrier layer, as part of the sealing layer, can reduce the risk of the connecting member breaking through the sealing layer due to the thin thickness of the adhesive film on the surface of the connecting member, and the composite film can also be used to block moisture and improve the performance of the grid line structure. [Brief description of the drawings]

[0021] One or more embodiments are illustratively described in the figures in the corresponding attached drawings, and these illustrative descriptions are not intended to limit the embodiments, and unless otherwise specified, the figures in the attached drawings do not form a proportional limit. In order to more clearly describe the embodiments of the present disclosure or the technical solutions in the prior art, the following will briefly describe the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can also obtain other drawings based on these drawings without paying creative labor. [Figure 1] FIG. 1 is a diagram showing a first type of configuration of a photovoltaic module according to an embodiment of the present application. [Diagram 2] FIG. 2 is a diagram showing a cross-sectional configuration along the c1-c2 cross section of FIG. [Diagram 3] FIG. 3 is a diagram showing a first type sectional configuration along the a1-a2 cross section of FIG. [Figure 4] FIG. 4 is a diagram showing a first configuration of a composite film in a photovoltaic module according to an embodiment of the present application. [Diagram 5] FIG. 5 is a diagram showing a second type sectional configuration along the a1-a2 section of FIG. [Figure 6] FIG. 6 is a diagram showing a second configuration of a composite film in a photovoltaic module according to an embodiment of the present application. [Figure 7] FIG. 7 is a diagram showing a third type sectional configuration along the a1-a2 cross section of FIG. [Figure 8] FIG. 8 is a diagram showing a third configuration of a composite film in a photovoltaic module according to an embodiment of the present application. [Figure 9] FIG. 9 is a diagram showing a second type of configuration of a photovoltaic module according to an embodiment of the present application. [Figure 10] FIG. 10 is a diagram showing a cross-sectional configuration along the c1-c2 cross section of FIG. [Figure 11] FIG. 11 is a diagram showing a third type of configuration of a photovoltaic module according to an embodiment of the present application. [Figure 12] FIG. 12 is a diagram showing a fourth type of configuration of a photovoltaic module according to an embodiment of the present application. [Figure 13] FIG. 13 is a diagram showing a cross-sectional configuration along the b1-b2 cross section of FIG. [Figure 14] FIG. 14 is a diagram showing the configuration of another photovoltaic module according to an embodiment of the present application. [Figure 15] FIG. 15 is a diagram showing a partially enlarged configuration of the fixing film in FIG. [Figure 16] FIG. 16 is a diagram showing a first type cross-sectional configuration along the line AA1 in FIG. [Figure 17] FIG. 17 is a diagram showing a second type cross-sectional configuration along the line AA1 in FIG. [Figure 18] FIG. 18 is a diagram showing a third type cross-sectional configuration along the line AA1 in FIG. [Figure 19] FIG. 19 is a diagram showing a fourth type cross-sectional configuration along the line AA1 in FIG. [Figure 20] FIG. 20 is a flow chart corresponding to another method for manufacturing a photovoltaic module according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] As can be seen from the background art, current photovoltaic module yields are poor.

[0023] Analysis shows that one of the reasons for the poor yield of photovoltaic modules is that when sunlight enters the cell from the front of the cell, the metal electrode on the front blocks part of the silicon wafer, and the light energy of this part irradiated on the electrode cannot be converted into electrical energy. From this perspective, the finer the grid line, the better. The role of the grid line is to conduct current, and from the viewpoint of resistivity, it is found that the finer the grid line, the smaller the conductive cross-sectional area and the greater the resistance loss. Therefore, the core of the design of the main grid and auxiliary grid is to balance light shielding and conductivity, and the PV ribbon that then makes electrical contact with the grid line must also balance light shielding and conductivity. In addition, in the conventional technology, to realize the alloying of the PV ribbon and the grid line, heat is usually radiated from the top of the PV ribbon toward the battery cell at a temperature 20°C higher than the temperature of the PV ribbon to dissipate heat. Due to the high melting temperature of such PV ribbons, it is necessary to increase the reflow temperature during welding. This makes it easy for thermal warping to occur in the battery cell. The thermal warping of the battery cell may damage the integrity of the spot welds formed and affect their performance. Thermal warping of the battery cells can also cause various tin solder defects, such as battery cell breakage, head-in-pillow defects, and cold solder joints.

[0024] In addition, when the connecting member adopts a low melting point metal as a solder, the lamination process is used to realize the alloying between the grid line structure and the connecting member. For example, in the module lamination process, the low melting point metal and the grid line structure are bonded by the pressure and temperature of the laminator. However, the melting point of the adhesive film is lower than the melting point of the solder in the PV ribbon. Therefore, in the process of welding the low melting point metal and the grid line structure, the pressure of the adhesive film in the molten state usually causes the PV ribbon to shift, or the adhesive film to overflow between the PV ribbon and the fine grid, causing the battery cell to crack or cold solder connection, which affects the battery performance and leads to a poor contact effect between the grid line structure and the connecting member.

[0025] In an embodiment of the present application, a photovoltaic module is provided. Between the connecting member and the sealing layer, a composite film is provided covering the surface of the connecting member, the composite film includes an adhesive layer and a blocking layer, the adhesive layer is used to fix the relative position between the connecting member and the battery cell, and prevent the molten sealing layer from pressing the connecting member and causing the connection member to be misaligned, and the blocking layer is used to prevent the molten sealing layer from flowing between the connecting member and the battery cell during the lamination process, thus causing problems in the electrical connection between the battery cell and the connecting member, thereby improving the weldability of the module, increasing the tensile force in the extension direction of the PV ribbon, improving the welding quality of the module, reducing problems such as cold solder connection of the module, improving the product quality of the module, reducing abnormalities such as re-repair during the manufacturing process of the module, and greatly increasing the productivity of the module. Meanwhile, the glass transition temperature of at least one of the adhesive layer and the blocking layer is higher than the glass transition temperature of the sealing layer, and while the sealing layer is in a molten state during the lamination process, one of the adhesive layer and the blocking layer is in a relatively dense solid state. This can prevent the molten adhesive film from flowing between the grid line structure and the connecting member. In addition, the adhesive layer and the barrier layer, as part of the sealing layer, can reduce the risk of the connecting member breaking through the sealing layer due to the thin thickness of the adhesive film on the surface of the connecting member, and the composite film can also be used to block moisture and improve the performance of the grid line structure.

[0026] The following describes in detail each embodiment of the present application with reference to the drawings. Those skilled in the art can understand that in each embodiment of the present application, many technical details are proposed to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications according to the following embodiments, the technical means in the claims of the present application can be realized.

[0027] FIG. 1 is a diagram showing a first type of configuration of a photovoltaic module according to an embodiment of the present application, and FIG. 2 is a diagram showing a first type of configuration of a photovoltaic module according to an embodiment of the present application. 1 -c 2 FIG. 3 is a diagram showing a cross-sectional configuration along a cross section of FIG. 1 -a 2FIG. 4 is a diagram showing a first type of cross-sectional configuration along a cross section, FIG. 5 is a diagram showing a first type of configuration of a composite film in a photovoltaic module according to an embodiment of the present application, and FIG. 1 -a 2 FIG. 6 is a diagram showing a second type of cross-sectional configuration along the cross section, and FIG. 7 is a diagram showing a second type of configuration of a composite film in a photovoltaic module according to an embodiment of the present application. 1 -a 2 FIG. 8 is a diagram showing a third type of cross-sectional configuration along a cross section, FIG. 8 is a diagram showing a third type of configuration of a composite film in a photovoltaic module according to an embodiment of the present application, FIG. 9 is a diagram showing a second type of configuration of a photovoltaic module according to an embodiment of the present application, and FIG. 10 is a diagram showing a cross-sectional configuration of FIG. 1 -c 2 11 is a diagram showing a cross-sectional configuration along a cross section, FIG. 11 is a diagram showing a third type of configuration of a photovoltaic module according to an embodiment of the present application, FIG. 12 is a diagram showing a fourth type of configuration of a photovoltaic module according to an embodiment of the present application, and FIG. 13 is a diagram showing a cross-sectional configuration along a cross section of FIG. 1 -b 2 FIG.

[0028] Here, the sealing layer and cover plate of the photovoltaic module in Figures 1, 9, 11 and 12 are not shown or are in a see-through state, to show and explain the position and connection relationship between the battery cells and the connection members. The cross-sectional views in Figures 3, 5, 7 and 13 only show the film layer structure on one side of the cell, and the film layer structure on the other side of the cell may be the same as or different from the film layer structure on the corresponding one side of the cell. As can be understood, the photovoltaic module shown in Figures 3, 5, 7 and 13 is a diagram showing a configuration in which no lamination process is performed, that is, the sealing layer does not fill the gap between the battery cells, and the connection members and the grid line structure are not alloyed. After the photovoltaic module in the above figures is laminated, the shape of the composite film can be changed. The specific shape is not limited in the examples of this application, but the composite film still covers the surface of the connection member.

[0029] As shown in FIGS. 1 to 13 , according to some embodiments of the present application, the present application provides a battery cell 10 including a plurality of battery cells 10 each having a grid line structure 101 arranged at intervals along a first direction X, a plurality of connection members 11 arranged at intervals along a second direction Y, the connection members 11 being located on a surface of the battery cell 10 and a surface of the grid line structure 101, the connection members 11 being electrically connected to adjacent battery cells 10, and a plurality of composite films 12 covering the surfaces of the connection members 11, the connection members 11 being arranged at intervals along the second direction Y. In accordance with the above, a photovoltaic module is provided, which includes a composite film 12 covering the surface of a battery cell 10 on both sides, the composite film 12 having an adhesive layer 121 and a barrier layer 122, the adhesive layer 121 being located between the barrier layer 122 and a connecting member 11, a sealing 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 higher than the glass transition temperature of the sealing layer 13, and a cover plate 14 located on the side of the sealing layer 13 away from the battery cell 10.

[0030] In some embodiments, the battery cell 10 includes, but is not limited to, any one of a PERC cell, a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact cell), and a HIT / HJT cell (Heterojunction Technology cell). In some embodiments, the battery cell 10 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multicomponent solar cell, and the multicomponent solar cell may specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0031] In some embodiments, the battery cell 10 is an interdigitated back contact (IBC) solar cell. An IBC cell refers to a back-contact solar cell structure in which positive and negative metal electrodes are arranged in a comb-like pattern on the backlight surface of the battery, and the PN junction and electrodes are located on the back surface of the battery, i.e., the electrodes of the emitter region and base region of the IBC battery are both on the back surface, and there is no shielding of grid lines on the front surface, which can improve the photoelectric conversion efficiency of the battery. In the cross-sectional view shown in the drawings, the film layer structure on one side of the battery cell 10 is different from the film layer structure on the other side of the battery cell 10, and each film layer structure of the battery cell 10 includes an encapsulation layer 13 and a cover plate 14.

[0032] The battery cell 10 is an integrated battery or a split battery. A split battery is a battery cell in which a complete integrated battery is formed through a cutting process. The cutting process includes a laser slot + cut (Linear Spectral Clustering, LSC) process and a thermal stress battery separation (TMC) process. In some embodiments, the split battery is a half-split battery, and the half-split battery can be understood as a half-cut battery or a two-split battery. The role of the half-cut battery module is to increase the power generation by reducing the resistance loss. From Ohm's law, it can be seen that the electrical loss of the solar cell interconnect is proportional to the square of the magnitude of the current. When the battery is cut in half, the magnitude of the current is also halved, and the electrical loss is also reduced to 1 / 4 of the full-size battery loss. As the number of batteries increases, the number of battery gaps also increases accordingly, and due to the reflection of the back plate of the module, the battery gaps help to increase the short circuit current. In addition, the half-cut battery module can optimize the width of the PV ribbon of the battery, whereas in the past, it was necessary to optimize the balance between increasing the width of the PV ribbon to reduce the electrical loss and reducing the width of the PV ribbon to reduce the shading loss. The half-cut battery module reduces battery loss, and the narrow width of the PV ribbon can reduce shading loss, which helps improve battery efficiency and power generation. In some embodiments, the split battery can be a 3-split battery, a 4-split battery, or an 8-split battery, etc.

[0033] In some embodiments, a photovoltaic module includes at least two battery cells 10, and in order to achieve electrical isolation between different battery cells 10, the at least two battery cells 10 are connected in series or parallel by connecting members 11 to form a battery string set, with a battery gap between adjacent battery cells 10.

[0034] In some embodiments, the grid line structure 101 is used to collect the photo-generated current in the solar cell and send it out of the battery cell 10. The battery cell includes main grids and auxiliary grid lines, the auxiliary grid lines and the main grid lines cross each other, the auxiliary grid lines are used to collect the current of the substrate, and the main grid lines are used to collect the current of the auxiliary grid lines and send it to the PV ribbons. In some embodiments, the grid line structure 101 is an auxiliary grid line, which is also called a sub-grid line and is used to guide the current. The battery cell 10 has a main gridless design, which shortens the carrier transport path, reduces the series resistance, and thus increases the front light receiving area, which is helpful in increasing the module power and improving the short circuit current, and reduces the amount of silver slurry used for printing the grid lines to reduce production costs.

[0035] In some embodiments, the gridline structure 101 includes a first electrode 111 and a second electrode 112. A first surface of the battery cell 10 includes the first electrode 111 and an opposing side, i.e., a second surface, includes a second electrode 112, where the first electrode 111 is one of a positive electrode or a negative electrode and the second electrode 112 is the other of a positive electrode or a negative electrode. The connecting member 11 connects the first electrode 111 of any battery cell 10 and the second electrode 112 of an adjacent battery cell 10.

[0036] In some embodiments, as shown in Figures 1 and 2, when the first surfaces of the battery cells 10 all face the same side and the second surfaces of the battery cells 10 all face the same side, or when the first electrodes 111 of all the battery cells all face the same side and the second electrodes 112 of all the battery cells all face the same side, the connection member 11 naturally needs to extend from the first surface of the battery cell to the second surface of the adjacent battery cell so that the connection member 11 connects the first electrode 111 and the second electrode 112 of the adjacent battery cell 10.

[0037] In some embodiments, as shown in Figures 9 and 10, when the battery cells 10 are arranged in the order of first surface, second surface, first surface and second surface, the connection member 11 does not bend and the connection member 11 directly connects the first electrode 111 and the second electrode 112 of the adjacent battery cell 10.

[0038] In some embodiments, the connection members 11 are PV ribbons, which are used for interconnection between the battery cells 10 and collect and transmit current to external elements of the photovoltaic module. The PV ribbons include bus PV ribbons for connecting the solar cell strings and the junction box, and interconnection PV ribbons for connecting between the battery cells 10.

[0039] In some embodiments, the connection member 11 has a core-coated structure, and includes a conductive layer and a welded layer that coats the surface of the conductive layer. Since the conductive layer is the main conductive transmission layer of the connection member 11, the lower the electrical resistivity of the conductive layer, the smaller the electrical loss of the connection member 11, and the higher the battery efficiency and power generation. The material of the conductive layer is a conductive material with good electrical conductivity, such as copper, nickel, gold, silver, etc., or an alloy material with low electrical resistivity.

[0040] In some embodiments, the welding layer may be plated or coated on the surface of the conductive layer, specifically, the source material of the welding layer may be uniformly coated around the conductive layer with a certain component ratio and thickness by using a special process such as electroplating, vacuum deposition, spray coating, hot-dip plating, etc. The main role of the welding layer is to make the connection member 11 satisfy the weldability and firmly weld the connection member 11 to the grid line structure 101 of the battery cell 10, so as to play a role of good current conduction.

[0041] In some embodiments, the material of the weld layer is a metal or alloy material with a lower melting point than the conductive layer, such as a tin alloy, including a tin-zinc alloy, a tin-bismuth alloy, or a tin-indium alloy. Welding using tin as a welding material has good weld fastness because of the low melting point of tin and good affinity with metals such as copper. The lead in the tin-lead alloy can lower the melting point of the PV ribbon, and tin and lead can form a eutectic with a melting point of 183°C, and have good welding and use performance. In the disclosed embodiments of the present application, other metal elements are used instead of lead, or other elements such as bismuth are added to the tin-lead alloy, and the use of bismuth can lower the melting point temperature and reduce the surface tension. The melting point of the tin-bismuth alloy can be lowered to 139°C, meeting the needs of low-temperature welding.

[0042] In some embodiments, the weld layer includes a flux. Flux refers to chemicals that aid or promote the welding process, provide protection, and inhibit oxidation reactions during the welding process. Fluxes include inorganic fluxes, organic fluxes, and resin fluxes. As can be appreciated, the melting point of the flux is lower than the melting point of the weld layer, which enhances the fluidity of the molten weld layer and allows good alloying between the weld layer and the gridline structure 101.

[0043] In some embodiments, the cross-sectional shape of the connecting members 11 is circular when taken along the second direction Y, which avoids orientation and alignment problems for circular PV ribbons and makes them easier to mass produce. In some embodiments, the cross-sectional shape of the connecting members 11 may be triangular or any other shape, which can increase the contact area between the PV ribbons and the gridline structure and reduce misalignment problems between the connecting members 11 and the gridline structure 101.

[0044] In some embodiments, a light reflecting layer is provided on the surface of the connection member 11 away from the battery cell 10, and the light reflecting layer is located on the conductive layer of the welding layer and on the outer surface away from the battery cell 10. The light reflecting layer is used to improve electrical loss caused by the shielding area of ​​the connection member 11 against the battery cell 10. In some embodiments, a light reflecting groove is provided on the outer surface of the welding layer, and the light reflecting groove is a groove or slot recessed from the welding layer toward the conductive layer, so that sunlight can be reflected to the battery cell 10 through the sidewall of the light reflecting groove, thereby improving the utilization rate of sunlight.

[0045] In some embodiments, the composite film 12 refers to a film layer composed of two or more materials in a certain ratio and in a certain shape. As shown in Figures 1 and 3, there is no contact between adjacent composite films 12, and the composite film 12 covers the surface of the connecting member 11, and the composite film 12 is also located on the surface of the battery cells 10 on both sides along the direction perpendicular to the first direction X of the connecting member 11. In this way, the composite film 12 completely covers the contact interface between the connecting member 11 and the grid line structure 101, which is used to prevent the molten sealing layer from penetrating the contact interface between the grid line structure 101 and the connecting member 11 during lamination, affecting the contact performance between the connecting member 11 and the grid line structure 101, and thus affecting the yield of the photovoltaic module. In addition, adjacent composite films 12 are not in contact with each other, and the shielding area of ​​the non-transparent composite film 12 against the battery cell 10 can be reduced to lower the optical loss, while adjacent composite films 12 are not in contact with each other and the internal defects (gaps or air gaps) of the photovoltaic module can be reduced as much as possible if the composite film 12 has a possibility of being inferior in softness and permeability to the encapsulating layer 13. Therefore, it is possible to exhaust air as much as possible, and to prevent the encapsulating layer 13 or composite film 12 from being detached from the surface of the battery cell 10 due to the air being heated, and thus to prevent water vapor from corroding the battery cell 10.

[0046] In addition, the above-mentioned composite film 12 can also be used as a part of the sealing layer 13 after the subsequent lamination process, which helps to reduce the thickness of the adhesive film on the surface of the connection member 11 and reduce the risk of the connection member 11 breaking through the sealing layer 13, and since the composite film 12 is a part of the sealing layer 13, the thickness of the sealing layer 13 can be reduced, thereby reducing the manufacturing cost of the sealing layer 13. When the thickness of the sealing layer 13 is reduced, the light absorption of the sealing layer 13 itself is reduced, and the sunlight received by the battery cell 10 is increased, which helps to improve the photoelectric conversion efficiency of the battery cell 10. The composite film 12 is also used to block moisture and improve the performance of the grid line structure 101.

[0047] In some embodiments, the pitch between adjacent composite films 12 is smaller than 5 / 6 of the pitch between adjacent connection members 11. This allows the area of ​​the composite film 12 covering the connection members 11 to be large, and does not require a large shielding area on the surface of the battery cell 10, thereby reducing the manufacturing cost and the shielding area of ​​the battery cell 10.

[0048] It should be noted that the above-mentioned pitch between adjacent composite films 12 can be regarded as the distance between the opposing sides of adjacent composite films 12, or the distance between the edges of the composite films 12. The pitch between adjacent connecting members 11 refers to the distance between the edges of the connecting members 11. Since the pitch between adjacent composite films 12 is smaller than 5 / 6 of the pitch between adjacent connecting members 11, the composite films 12 are located on the surface of the battery cells 10, and can more closely protect the contact structure between the connecting members 11 and the grid line structure 101.

[0049] In some embodiments, adjacent composite films 12 are continuous film layers along the second direction Y, i.e., adjacent composite films 12 are in contact with each other and are the same original film layer, as shown in Fig. 11. Thus, in the step of laying the composite films 12 in the manufacture of the photovoltaic module, there is no need to consider the alignment problem between the composite films 12 and the connecting members 11, which reduces the difficulty of the manufacture of the photovoltaic module to a certain extent.

[0050] It should be noted that along the second direction Y, it is sufficient to cover the surface of the connecting member 11 closest to the edge of the battery cell on the side of the composite film 12 closer to the edge of the battery cell, or it is sufficient that the first pitch between the edge of the composite film 12 and the opposite edge of the battery cell is smaller than the second pitch between the edge of the connecting member 11 and the opposite edge of the battery cell, and there are no specific numerical values ​​or ranges limited to the case where the first pitch between the edge of the composite film 12 and the opposite edge of the battery cell is smaller than the second pitch between the edge of the connecting member 11 and the opposite edge of the battery cell.

[0051] In some embodiments, the composite film 12 is a one-piece structure, in which case there is no misalignment or interfacial defects between the adhesive layer 121 and the barrier layer 122 prior to the lamination process, thereby enhancing the overall performance of the composite film 12.

[0052] In some embodiments, along the first direction X, the composite film 12 covers the connection members 11 of the multiple battery cells 10, i.e., the composite film 12 is also located in the battery gaps between adjacent battery cells 10, thereby achieving complete coverage of the connection members 11 by the composite film 12 and preventing the molten sealing layer 13 from penetrating between the gridline structure 101 and the connection members 11 from the edges of the battery cells 10.

[0053] It can be seen that for a battery cell, along the first direction X, the length of the composite film 12 is greater than the length of the battery cell 10, and the length of the composite film 12 is less than or equal to the length of the connecting member 11, thereby ensuring that the molten sealing layer 13 does not penetrate between the gridline structure 101 and the connecting member 11 from the edge of the battery cell 10, and the manufacturing cost of the composite film 12 is also low.

[0054] In some embodiments, adhesive layer 121 refers to a film layer made of a viscous material that is used to secure connecting member 11 to battery cell 10 and prevent connecting member 11 from shifting during steps prior to lamination and to prevent connecting member 11 from shifting during lamination due to the molten sealing layer pressing against connecting member 11.

[0055] In some embodiments, the material of the adhesive layer 121 includes EVA (ethylene vinyl acetate copolymer), acrylate or PE (polyethylene), etc. When the material of the adhesive layer 121 is EVA, the adhesive layer 121 can ensure that the adhesive layer 121 has the adhesiveness to fix the connection member 11 to the battery cell 10, and at the same time, the adhesive layer 121 has a certain water resistance and corrosion resistance, and can be used as a barrier layer to prevent the molten sealing layer 13 from penetrating into the connection member 11 and the grid line structure 101 and a protective layer to prevent water vapor. Because the manufacturing cost of EVA is low, the manufacturing cost of the composite film 12 is correspondingly low.

[0056] When the material of the adhesive layer 121 is an acrylate-based material, the acrylate-based material has a certain transparency and reduces the optical loss of the battery cell 10. The acrylate-based material can be directly cured in a low-temperature environment and has a fast curing speed, which reduces the thermal stress experienced by the battery cell 10, reduces the risk of damage to the battery cell 10, and helps to improve the yield of the photovoltaic module. The acrylate-based material has excellent water resistance and can be used to prevent damage to the connection member 11 caused by water vapor.

[0057] In some embodiments, the thickness of adhesive layer 121 ranges from 10 μm to 150 μm. The thickness of adhesive layer 121 may range from 10 μm to 130 μm, 10 μm to 109 μm, 10 μm to 85 μm, 10 μm to 139 μm, 30 μm to 150 μm, 68 μm to 150 μm, 102 μm to 150 μm, or 49 μm to 124 μm. The thickness of adhesive layer 121 may specifically be 15 μm, 29 μm, 65 μm, 89 μm, 106 μm, 134 μm, or 150 μm. When the thickness of the adhesive layer 121 is within the above range, the adhesive layer 121 has a sufficient thickness to fix the connecting member 11 to the surface of the battery cell 10, and no shifting will occur in subsequent steps. In addition, the adhesive layer 121 does not occupy a large portion of the thickness of the photovoltaic module, so that the thickness of the photovoltaic module can be reduced to a certain extent, and high integration of the photovoltaic module can be achieved.

[0058] In some embodiments, the glass transition temperature range of the adhesive layer 121 is −55° C. to 0° C., and the glass transition temperature range of the adhesive layer 121 ensures that the adhesive layer 121 is in a highly elastic state at room temperature. In this way, the adhesive layer 121 exhibits a certain degree of adhesion, which enables the composite film 12 to fix the connecting member 11 and prevent the connecting member 11 from shifting, and prevents water vapor and the molten sealing layer from penetrating through the contact interface between the battery cell 10 and the composite film 12. At the same time, a modifier with a relatively high glass transition temperature is added to the viscous pure polymer material in the adhesive layer 121, so that the glass transition temperature of the adhesive layer 121 is higher than the glass transition temperature of the sealing layer 13. When the sealing layer is in a molten state, the adhesive layer 121 is not yet melted and is in a glass state, and the molten sealing layer cannot penetrate between the connecting member 11 and the grid line structure 101 through the adhesive layer 121. The glass transition temperature range of the adhesive layer 121 is -58 to -1°C, -48 to -12°C, -31 to -1°C, or -38 to -15°C.

[0059] Here, the glass transition temperature (Tg) is the temperature at which the material changes from a glassy state to a highly elastic state (rubbery state). When the temperature is low, the material is in a rigid solid state, and similar to glass, only very small deformation occurs due to external forces. This state is the glassy state. As the temperature continues to rise within a certain range, the deformation of the material increases obviously, and then in a certain temperature range, the deformation becomes relatively stable. This state is the highly elastic state, and as the temperature continues to rise, the amount of deformation gradually increases and the material gradually becomes a viscous fluid, at which point the deformation cannot be recovered. This state is the viscous flow state. The glass transition temperature can be measured using a DSC (Differential Scanning Calorimetry) instrument.

[0060] In some embodiments, the barrier layer 122 refers to a film layer with a certain insulating performance, which is used to prevent the molten sealing layer 13 from penetrating between the connecting member 11 and the grid line structure 101 and to block water vapor. The material of the barrier layer 122 includes PET (polyethylene terephthalate), POE (polyolefin elastomer), liquid silica gel or PVB (polyvinyl butyral). POE is a non-polar material with excellent water vapor blocking ability and ion blocking ability, and its water vapor transmission rate is about 1 / 8 of that of EVA film. Due to its stable molecular chain structure, it does not decompose during the degradation process to produce acidic substances, and has excellent anti-degradation performance. PVB has excellent water resistance, resistance and oil resistance, and PVB resin has excellent optical clarity, its refractive index is close to that of glass, and the image viewed through the laminated glass does not appear with optical distortion or double phase, and the loss of incident light contacting the photovoltaic module surface can be reduced. PVB does not deform in a wide temperature range, has robustness combined with flexibility and excellent impact resistance, and has extremely high adhesion efficiency with various glass surfaces. Liquid silica gel has excellent tear strength, resilience, yellowing resistance, thermal stability and thermal degradation resistance, and has moderate adhesion, is easy to handle and provides high product transparency.

[0061] In some embodiments, the thickness range of the blocking layer 122 is 20 μm to 50 μm. The thickness range of the blocking layer 122 can be 20 μm to 45 μm, 20 μm to 38 μm, 20 μm to 31 μm, 25 μm to 50 μm, 36 μm to 50 μm, 23 μm to 48 μm, 31 μm to 42 μm, or 30 μm to 40 μm. The thickness of the blocking layer 122 can be specifically 23 μm, 26 μm, 31 μm, 36 μm, 39 μm, 45 μm, or 50 μm. When the thickness of the blocking layer 122 is within the above range, the blocking layer 122 has a sufficient thickness of the sealing layer to prevent water vapor and molten state, and the blocking layer 122 does not occupy a large thickness of the photovoltaic module, thereby reducing the thickness of the photovoltaic module to a certain extent and realizing high integration of the photovoltaic module. In addition, the blocking layer 122 has low light absorption, which helps improve the photoelectric conversion efficiency of the battery cell.

[0062] 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 adhesive layer 121 to the thickness of barrier layer 122 may be 1 / 5 to 50, 1 / 5 to 35, 1 / 5 to 10, 1 to 75, 18 to 75, 35 to 75, 25 to 51, or 39 to 73. The ratio of the thickness of adhesive layer 121 to the thickness of barrier layer 122 may specifically be 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 blocking layer 122 are within the above ranges, and if the thickness of the adhesive layer 121 is large, the proportion of the blocking layer 122 will be small and the softness of the adhesive layer 121 will be greater than that of the blocking layer 122, and if the proportion of the adhesive layer 121 is large, the composite film 12 will be able to approach the connecting member 11 more easily and the gap between the composite film 12 and the connecting member 11 will be smaller. If the thickness of the blocking layer 122 is large, the blocking effect will be high and it will be possible to prevent water vapor and the like from penetrating into the battery cell 10. Here, softness refers to the flexibility of the film layer or the degree of adhesion between the film layer and the connecting member.

[0063] In some embodiments, at the same preset temperature, the adhesion of the adhesive layer 121 is greater than the adhesion of the blocking layer 122, in which case the adhesive layer 121 can have sufficient adhesion to ensure adhesion performance between the connecting member 11 and the battery cell 10, and the space formed by the composite film 12 and the battery cell 10 can have a certain degree of density to prevent the intrusion of the sealing layer 13.

[0064] In some embodiments, the adhesive layer 121 has a viscosity range of 8000-20000 mPa·s before lamination and curing. The viscosity range of the adhesive layer 121 allows the adhesive layer 121 to have a certain fluidity before curing, and poor density, allowing air to escape, which then heats the adhesive layer 121 to open, preventing the molten film from flowing between the connecting members and the gridline structure. After lamination and curing, the adhesive layer 121 has a viscosity of 10000-30000 mPa·s, providing sufficient connection strength between the connecting members 11 and the surfaces of the battery cells 10, providing protection for the connecting members 11, and preventing the intrusion of the sealing layer 13 during lamination and the erosion of water vapor during long-term use of the module.

[0065] In some embodiments, the material of barrier layer 122 is different from the material of adhesive layer 121 and has a water permeability range of 2 to 4 g / m 2 The water permeability range of the blocking layer 122 is 2 to 3.3 g / m 2 , 2~2.8g / m 2 , 2~2.64g / m 2 , 2.35~3.89g / m 2 , 2.8~3.96g / m 2 or 2.6 to 3.35 g / m 2 The water permeability of the barrier layer 122 is specifically 2.05 g / m 2 , 2.45g / m 2 , 2.98g / m 2 , 3.17g / m 2 , 3.56g / m 2 or 4 g / m 2 If the barrier layer 122 is within the above range, it indicates that the barrier layer 122 has good barrier performance. The barrier performance is the barrier performance of water vapor, and refers to the blocking effect of the packaging material against liquid, water vapor, and other permeants. If the barrier performance is good, the sealing layer in a molten state cannot pass through the barrier layer 122. Small molecules and water vapor in the permeated sealing layer cannot pass through, so the connecting member 11 can be well protected.

[0066] Here, water permeability (water vapor permeability) has two meanings: water vapor transmission rate and water vapor transmission coefficient. Water vapor transmission rate indicates the weight of water vapor that permeates a material under constant temperature and humidity conditions for a certain period of time. Water vapor transmission rate indicates the amount of water vapor that permeates a sample per unit thickness and unit area under unit water vapor pressure difference in a specified temperature and relative humidity environment within a unit time.

[0067] In some embodiments, the glass transition temperature range of the barrier layer 122 is 100-200° C., and the glass transition temperature range of the barrier layer 122 may be 130-200° C., 153-200° C., 189-200° C., or 150-184° C. 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 higher than the glass transition temperature of the sealing layer 13, such that when the sealing layer is in a molten state, the barrier layer 122 is not yet melted and is in a glassy state, and the molten sealing layer cannot penetrate through the barrier layer 122 to infiltrate between the connecting member 11 and the gridline structure 101.

[0068] In some embodiments, a plasticizer can be added to the barrier layer 122 to enhance the isolation performance of the barrier layer 122. In some embodiments, small molecules having viscosity can be added to the barrier layer 122 to enhance the connection effect between the barrier layer 122 and the battery cell, and prevent the connection member from shifting or the sealing layer from penetrating. In some embodiments, small molecules having a high glass transition temperature can be added to the barrier layer 122 to further increase the glass transition temperature of the barrier layer 122.

[0069] 5 and 6, when the barrier layer 122 surrounds a portion of the adhesive layer 121, the barrier layer 122 surrounds the adhesive layer 121. A large proportion of the barrier layer 122 is present at the contact interface between the battery cell 10 and the composite film 12, and is used to prevent the infiltration of water vapor from the molten sealing layer 13.

[0070] 7 and 8, the adhesive layer 121 surrounds a part of the barrier layer 122, and the barrier layer 122 does not contact the battery cell 10, in which case the contact surface between the adhesive layer 121 and the battery cell 10 is large, the adhesion effect between the composite film 12 and the battery cell 10 is improved, and the probability of misalignment between the battery cell 10 and the connecting member 11 is reduced. In addition, if the density of the adhesive layer 121 is poorer than that of the barrier layer 122, the air between the adhesive layer 121, the battery cell 10, and the connecting member 11 will be discharged through the adhesive layer 121, so that the air will be present in the space surrounded by the composite film 12 during the subsequent lamination process or any heat treatment process, and the composite film 12 will not be pushed open, and thus the composite film 12 will not be separated from the battery cell 10.

[0071] In addition, in the covering structure formed in the form of the photovoltaic module composite film 12 in Figure 6 above, the width of the blocking layer 122 located on the side of the adhesive layer 121 should be set according to the actual situation, and there should be a contact interface between the adhesive layer 121 and the battery cell 10, and the proportion of the contact interface should not be too small, so that the effect of the adhesive layer 121 can be fully exerted.

[0072] In some embodiments, the side of the composite film 12 away from the battery cell 10 has a light reflective layer or light emitting grooves to improve the utilization of sunlight and increase the photoelectric conversion efficiency of the battery cell.

[0073] In some embodiments, as shown in Figures 12 and 13, the photovoltaic module further includes adhesive dots 102 located on the surface of the battery cells 10 and between adjacent gridline structures 101, and the connecting members 11 are located on the adhesive dots 102.

[0074] In some embodiments, the adhesive material used to make the adhesive dots 102 is preferentially selected to be a transparent adhesive, so as to ensure as much light absorbing area as possible on the surface of the battery cell 10, and to avoid the installation of the adhesive dots 102 reducing the light absorbing area on the surface of the battery cell 10, which would then affect the efficiency of the solar cell.

[0075] In some embodiments, the number of adhesive dots 102 for one connection member 11 is 2 to 20. The pitch between adjacent adhesive dots 102 is 5 mm to 100 mm. Depending on the number or pitch of the adhesive dots 102, the fixing effect between the connection member 11 and the battery cell 10 can be improved, and the connection member 11 will not shift before and during the lamination process; meanwhile, the number of adhesive dots 102 can affect the optical loss of the battery cell 10 and obtain more electrical properties.

[0076] As can be seen, the battery cell 10 in the photovoltaic module is a battery cell of main grid-less design, that is, no main grid is installed on the surface of the battery cell, and current collection on the surface of the battery cell is realized by directly alloying with fine grids via connecting members 11. However, the composite film of the photovoltaic module proposed in the embodiments of the present application can be equally applied to normal battery cells with main grids, and is used to improve the contact between the main grid and connecting members, thereby improving the yield of the photovoltaic module.

[0077] In some embodiments, the sealing layer 13 includes a first sealing layer and a second sealing layer, where the first sealing layer covers one of the front and back surfaces of the battery cell 10, and the second sealing layer covers the other of the front and back surfaces of the battery cell 10; specifically, at least one of the first sealing layer or the second sealing layer may be an organic sealing film such as an ethylene vinyl acetate copolymer (EVA) adhesive film, an ethylene octene copolymer (POE) adhesive film, or a polyvinyl butyral (PVB) adhesive film.

[0078] In some embodiments, the melting point of the seal layer 13 is less than the lamination temperature during the lamination process. The seal layer 13 is formed when the film is in a molten state at the temperature of the laminator, and the initiator in the seal layer 13 causes the small molecules in the film to bond together to form a film layer composed of crosslinked large molecules.

[0079] In some embodiments, the magnitude of the melting point of the encapsulation layer 13 and the melting point of the connecting member 11 can be set according to actual circumstances. If the melting point of the encapsulation layer 13 is higher than the melting point of the connecting member 11, the connecting member 11 can be alloyed before the encapsulation layer 13 is in a molten state, and the molten film can be effectively prevented from penetrating into the grid line structure 101 and the connecting member 11 and pushing the connecting member 11 out of place. If the melting point of the encapsulation layer 13 is lower than the melting point of the connecting member 11, the lamination temperature can be set lower to improve the thermal stress experienced by the battery cells and increase the yield of the photovoltaic modules.

[0080] In some embodiments, the glass transition temperature of at least one of the adhesive layer 121 and the barrier layer 122 is higher than the glass transition temperature of the sealing layer, so that when the sealing layer 13 is in a molten state, the adhesive layer and the barrier layer can still maintain a good shape, and the molten film can effectively avoid penetrating the grid line structure 101 and the connecting members 11 and pushing the connecting members 11 out of place.

[0081] In some embodiments, the glass transition temperature of the encapsulating layer is −70 to −10° C., and the glass transition temperature of the encapsulating layer is used to ensure that the encapsulating layer is in a molten state during lamination processing, so that each gap of the photovoltaic module can be filled and the yield of the photovoltaic module can be increased.

[0082] In some embodiments, the cover plate 14 may be a cover plate with a light transmission function, such as a glass cover plate, a plastic cover plate, etc. Specifically, the surface of the cover plate 14 facing the sealing layer 13 may be an uneven surface, which can improve the utilization rate of the incident light. The cover plate 14 includes a first cover plate and a second cover plate, the first cover plate facing the first sealing layer, and the second cover plate facing the second sealing layer.

[0083] In the photovoltaic module according to the embodiment of the present application, a composite film 12 is disposed between the connecting member 11 and the sealing layer 13, the composite film 12 covers the surface of the connecting member 11, and the composite film 12 includes an adhesive layer 121 and a blocking layer 122. The adhesive layer 121 can be used to fix the relative position between the connecting member 11 and the battery cell 10, and prevent the molten sealing layer 13 from pressing the connecting member 11 and causing the connecting member 11 to be misaligned. The blocking layer 122 is used to prevent the molten sealing layer 13 from flowing between the connecting member 11 and the battery cell 10 during lamination processing, causing problems in the electrical connection between the battery cell 10 and the connecting member 11. This improves the weldability of the module, increases the tension in the PV ribbon direction, improves the welding quality of the module, reduces problems such as cold solder connection of the module, improves the product quality of the module, reduces abnormalities such as returns and repairs during the module manufacturing process, and greatly increases the productivity of the module. Meanwhile, the glass transition temperature of at least one of the adhesive layer 121 and the barrier layer 122 is higher than the glass transition temperature of the sealing layer 13, so that during lamination, the sealing layer 131 is in a molten state, while one of the adhesive layer 121 and the barrier layer 122 is in a relatively dense solid state. This can prevent the molten film from flowing between the grid line structure 101 and the connecting member 11. In addition, the adhesive layer 121 and the barrier layer 122 can be used as a part of the sealing layer 13, so that the thickness of the sealing layer 13 on the surface of the connecting member 11 is thin, and the risk of the connecting member 11 breaking through the sealing layer 13 can be prevented. The composite film 12 can be used to block moisture and improve the performance of the grid line structure.

[0084] In addition, some embodiments of the present application further provide, in another form of the embodiments of the present application, a method for manufacturing a photovoltaic module, which is used to manufacture the photovoltaic module provided in the above embodiments, and the same devices or corresponding parts as the above embodiments do not need to be described repeatedly here.

[0085] In some embodiments, a method for manufacturing a photovoltaic module includes: providing a plurality of battery cells, each battery cell including a grid line structure S1 spaced apart along a first direction; providing a plurality of connection members arranged at intervals along a second direction, the connection members being located on a surface of the battery cells and electrically connected to adjacent battery cells S2; S3, providing a plurality of composite films, the composite films covering a surface of a connecting member, and both sides of the composite films covering a surface of a battery cell along the second direction, the composite films including an adhesive layer and a barrier layer, the adhesive layer being located between the barrier layer and the connecting member; providing a sealing layer covering a surface of the composite film, wherein the glass transition temperature of at least one of the adhesive layer and the barrier layer is greater than the glass transition temperature of the sealing layer; providing a cover plate S5 located on a side of the sealing layer away from the battery cell; and S6, performing lamination processing.

[0086] In some embodiments, the process for producing the composite film includes: uniformly mixing the raw materials of the adhesive layer according to a compounding ratio and extruding them through an extrusion device to form a first raw material; uniformly mixing the raw materials of the barrier layer according to a compounding ratio and extruding them through an extrusion device to form a second raw material; pouring either the first raw material or the second raw material according to a compounding ratio into a molding device to form an initial film; co-extrusion compounding; and pouring the other of the first raw material and the second raw material into a molding device and forming a composite film by screw extrusion compounding.

[0087] In some embodiments, the initial film is made of a second raw material, and after the manufacturing process of forming the initial film, the process further includes extruding and slotting the initial film through a mold to form a receiving groove in the initial film; placing the first raw material in a semi-fluid state in the receiving groove of the initial film in a semi-fluid state in a co-extrusion compounding, screw extrusion compounding, extruding through a forming mold, and pouring the film sheet into a sheet-like form onto the roll surface of a gently rotating cooling roll, cooling and shaping the film sheet on the cooling roll, and winding the product after being drawn and edge-cut.

[0088] In some embodiments, the method includes laying an adhesive dot between S1 and S2, the adhesive dot being located on the surface of the battery cell and located between adjacent gridline structures, and the connecting member being located on the adhesive dot. After laying the connecting member, curing the adhesive dot to increase the adhesive dot's adhesion and enhance the curing ability between the connecting member and the battery cell. For example, the adhesive dot has an adhesion of 8000 mPa·s before curing and an adhesion of 10000 mPa·s after curing.

[0089] As described above, in the photovoltaic module technology, a battery string is usually formed by welding the main grid of the battery cell to the PV ribbon, and connecting the positive and negative poles of two adjacent battery cells with the PV ribbon. Then, the battery string is aligned to make a circuit connection, and is further sealed with a sealant to manufacture a photovoltaic module.

[0090] As can be seen from the background art, welding of the main grid and the PV ribbon is usually performed after arranging a certain number of infrared lamps to form a high-temperature area, and the tin-lead alloy on the surface of the PV ribbon melts at high temperature, fusing the PV ribbon with the silver paste of the main grid on the surface of the battery. However, when welding with a high-temperature process, the typical welding temperature is 220℃ to 350℃, so the battery cell is likely to warp due to stress, and problems such as hidden cracks and debris are likely to occur. In addition, due to the influence of the PV ribbon wire diameter and yield strength, there is a large stress between the battery cells in the traditional welding method, and the photovoltaic module is prone to hidden cracks under weather conditions such as wind and snow outdoors, which leads to a decrease in the power generation amount and a decrease in reliability of the photovoltaic module.

[0091] In order to avoid the infrared welding method, the PV ribbon can be manufactured with a low melting point metal as solder, and the PV ribbon can be fixed to the surface of the battery cell with a fixing film, and in the lamination process of the photovoltaic module, the low melting point PV ribbon and the grid line structure are bonded by the temperature and pressure of the laminator. However, the fixing film covers the PV ribbon and the surface of the battery cell on both sides of the PV ribbon, and forms an angle between the fixing film and the surface of the battery cell, and this angle and the side of the PV ribbon surround the adhesive gap, so that the gas in the adhesive gap will expand due to the heat during lamination, leading to the separation of the fixing film, and then the molten adhesive film is easy to flow between the PV ribbon and the surface of the battery cell, causing the insulation of the PV ribbon and the grid line structure, so it is necessary to exhaust the air in the adhesive gap. For example, multiple exhaust holes are provided in the adhesive gap corresponding to the fixing film, and the air in the adhesive gap is exhausted through the exhaust holes to the side of the fixing film away from the battery cell surface. In order to prevent the molten adhesive film from penetrating into the adhesive gap through the exhaust holes and causing insulation of the PV ribbon and the grid line structure, an exhaust hole with a specific structure is adopted to reduce the possibility of the molten adhesive film penetrating into the adhesive gap and increase the yield of the photovoltaic module.

[0092] Some embodiments of the present application further provide a photovoltaic module for increasing the yield of the photovoltaic modules.

[0093] Fig. 14 is a diagram showing the configuration of another photovoltaic module in one embodiment of the present application, Fig. 15 is a diagram showing a partially enlarged configuration of the fixing film in Fig. 14, Fig. 16 is a diagram showing a first type cross-sectional configuration along AA1 in Fig. 14, Fig. 17 is a diagram showing a second type cross-sectional configuration along AA1 in Fig. 14, Fig. 18 is a diagram showing a third type cross-sectional configuration along AA1 in Fig. 14, and Fig. 19 is a diagram showing a fourth type cross-sectional configuration along AA1 in Fig. 14. Hereinafter, the photovoltaic module in this embodiment will be described in detail with reference to the drawings.

[0094] As shown in FIGS. 14 to 17, the photovoltaic module includes a plurality of battery cells 10 arranged along a first direction X, a plurality of connection members 11 extending along the first direction X, the connection members 11 being located on the surfaces of the battery cells 10, and adjacent battery cells 10 being electrically connected via the connection members 11, and a plurality of fixing films 12, each of which covers the surface of one of the connection members 11 and covers the surfaces of the battery cells 10 on both sides of the connection member 11 perpendicular to the first direction X, and here, as shown in FIG. 16, the fixing films 12 located on at least one side of the connection members 11 and the surface of the battery cell 10, the angle α being formed so as to surround the adhesive gap 103 together with the side of the connecting member 11, the fixing film 12 having a plurality of exhaust holes 104 at a location corresponding to the adhesive gap 103, and the orthogonal projection of the exhaust holes 104 on the surface of the battery cell 10 and the orthogonal projection of the connecting member 11 on the surface of the battery cell 10 not overlapping, a sealing layer 105 covering the surface of the fixing film 12 and covering the surface of the battery cell 10 exposed from the fixing film 12, and a cover plate 106 covering the surface of the sealing layer 105 away from the battery cell 10.

[0095] In the photovoltaic module according to the embodiment of the present application, a plurality of battery cells 10 are electrically connected via the connection members 11, and each connection member 11 in any one of the battery cells 10 corresponds to one fixing film 12, and the fixing film 12 covers the surface of the connection member 11 and a part of the surface of the battery cells 10 on both sides of the connection member 11 perpendicular to the first direction X, thereby fixing the connection member 11 to the surface of the battery cells 10. In addition, the fixing film 12 can be an isolation layer between the connection member 11 and the sealing layer 105, and during the sealing process, the fixing film 12 can prevent the molten sealing layer 105 from flowing between the connection member 11 and the surface of the battery cells 10, and can prevent the insulation of the connection member 11 and the grid line structure on the battery cells 10 caused by the molten sealing layer 105. Here, there is an angle α between the fixing film 12 located on at least one side of the connecting member 11 and the surface of the battery cell 10, and this angle α is formed so as to surround the adhesive gap 103 together with the side of the connecting member 11, and the fixing film 12 has an exhaust hole 104 at a location corresponding to the adhesive gap 103. As a result, in the subsequent lamination process, the air in the adhesive gap 103 is discharged through the exhaust hole 104 to the side of the fixing film 12 away from the surface of the battery cell 10, thereby preventing the air in the adhesive gap 103 from expanding due to heat and causing the fixing film 12 to detach, improving the stability of the fixing film 12 and increasing the yield of the photovoltaic module.

[0096] In addition, as shown in FIG. 15, the position of the exhaust hole 104 corresponding to the adhesive gap 103 of the fixing film 12 can be provided by avoiding the grid line structure 101, and thus it is possible to prevent a small amount of melted sealing layer 105 from entering the adhesive gap 103 through the exhaust hole 104 and causing insulation between the connection member 11 and the grid line structure 101. In FIG. 15, an example is described in which three exhaust holes 104 are provided between adjacent grid line structures 101 and the number of exhaust holes 104 on both sides of the connection member 11 is equal, but this does not limit the number of exhaust holes 104 between adjacent grid line structures 101. In other embodiments, the number of exhaust holes between adjacent grid line structures may be 1, 4, 8, or 10. In other embodiments, the number of exhaust holes on both sides of the connection member may be different. In FIG. 15, the exhaust holes 104 on both sides of the connection member 11 are provided symmetrically along the connection member 11, but this does not limit the arrangement method of the exhaust holes 104 on both sides of the connection member 11. In another embodiment, the exhaust holes on both sides of the connection member may be offset along a direction perpendicular to the first direction.

[0097] 16 shows the photovoltaic module in a state before lamination processing, and FIG. 17 shows the photovoltaic module in a state after lamination processing. As shown in FIG. 16 and FIG. 17, when the photovoltaic module is being laminated, the air in the adhesive gap 103 can be exhausted from the exhaust hole 104 to the side of the fixing film 12 away from the surface of the battery cell 10 by the pressure of the sealing layer 105. After lamination processing, the air in the adhesive gap 103 is completely exhausted, the adhesive gap 103 disappears, and the fixing film 12 adheres to the side of the connection member 11 and the surface of the battery cell 10, and also adheres to the boundary between the connection member 11 and the surface of the battery cell 10.

[0098] In the case of the battery cell 10, the battery cell 10 may be one of a PERC cell, a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact cell), and a HIT / HJT cell (Heterojunction Technology cell). In some embodiments, the battery cell 10 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multicomponent solar cell, and the multicomponent solar cell may be specifically a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0099] For convenience of explanation, FIG. 14 shows only two adjacent battery cells 10 connected via a connection member 11, but this does not limit the number of battery cells 10 arranged. In other embodiments, the number of battery cells may be 4, 6, 8, or 15. In addition, FIG. 14 shows an example in which a first electrode is provided on the front surface of a battery cell, a second electrode is provided on the back surface of the battery cell, the first electrode is either a positive electrode or a negative electrode, and the second electrode is the other of the positive electrode or the negative electrode, and the front surfaces of all adjacent battery cells face upward, and the first electrode of any battery cell and the second electrode of the adjacent battery cell are electrically connected via a connection member, but this does not limit the arrangement of adjacent battery cells. In some embodiments, the multiple battery cells may be arranged with the front and back surfaces facing upward alternately along the first direction, and the connection members may all be located on the surface of the same side of the battery cells.

[0100] In some embodiments, the battery cell 10 may be an interdigitated back contact (IBC) battery, which refers to a back-junction back-contact solar cell structure in which positive and negative metal electrodes are arranged in a comb-like pattern on the backlight surface of the battery, and its PN junction and electrodes are located on the back surface of the battery, i.e., the electrodes of the emitter region and base region of the IBC battery are both on the back surface, and there is no grid line shielding on the front surface, which can improve the photoelectric conversion efficiency of the battery. That is, the back surface of the battery cell 10 has a first electrode and a second electrode, the first electrode being either a positive electrode or a negative electrode, and the second electrode being the other of the positive electrode or the negative electrode, and the first electrode on any battery cell of the adjacent battery cells is electrically connected to the second electrode on the adjacent battery cell via a connecting member.

[0101] In some embodiments, two adjacent battery cells 10 may be electrically connected in a series or parallel manner via a connecting member 11 to form a battery string group, and a battery gap may be provided between the adjacent battery cells 10 to realize electrical isolation between different battery cells 10.

[0102] In some embodiments, the surface of the battery cell 10 may have a grid line structure, which is used to collect the photo-generated current in the solar cell and transmit it to the outside of the battery cell. The grid line structure may include main grids and auxiliary grid lines, which extend in a direction intersecting with the main grid, and the auxiliary grid lines are used to collect the current of the substrate, and the main grid is used to collect the current of the auxiliary grid lines and transmit it to the connecting member.

[0103] 14 to 17, the surface of the battery cell 10 only includes auxiliary grid lines 101, that is, the battery cell 10 has a main-gridless design, and the connecting members 11 are fixed to the surface of the battery cell 10 via the fixing film 12, and then the connecting members 11 and the auxiliary grid lines 101 are directly alloyed by a lamination process, so that the auxiliary grid lines 101 on adjacent battery cells 10 are directly electrically connected via the connecting members 11, which reduces the installation of the main grid and helps to reduce the manufacturing cost of the battery cell 10. In addition, the main-gridless design shortens the carrier transport path and reduces the series resistance, which in turn increases the front light-receiving area and increases the power of the module.

[0104] 14 and 15, the auxiliary grid lines 101 extend along the second direction Y and the first direction X and the second direction Y are perpendicular to each other, but the angle between the first direction X and the second direction Y is not limited to this. In other embodiments, the angle between the first direction and the second direction may be 30°, 45°, or 60°.

[0105] In some embodiments, the surface of the battery cell includes a main grid and an auxiliary grid line, and the connecting member is located on the side of the main grid away from the surface of the battery cell and is in electrical contact with the main grid, thereby electrically connecting the main grids of adjacent battery cells through the connecting member. The present embodiments do not limit the installation manner of the grid line structure on the surface of the battery cell.

[0106] In the case of the connecting members 11, the connecting members 11 include PV ribbons, which are used to interconnect between the battery cells 10 and collect and transport current to external elements of the photovoltaic module. In some embodiments, the PV ribbons may include bus PV ribbons for connecting the photovoltaic battery strings and the junction box, and interconnection PV ribbons for connecting adjacent battery cells.

[0107] In some embodiments, the connection member 11 may be composed of a conductive layer and a welding layer covering the surface of the conductive layer, the material of the conductive layer includes a conductive material with good conductivity or an alloy material with low electrical resistivity, such as copper, nickel, gold, or silver, and the material of the welding layer includes a material with a low melting point, such as a tin-zinc alloy, a tin-bismuth alloy, or a tin-indium alloy. -7 When the electrical conductivity is less than Ω·m or greater than 1×107 S / m, the electrical loss of the conductive layer can be reduced, which helps to improve the efficiency of the battery and the power generation. The material of the weld layer is made of a material with a low melting point, which helps to meet the needs of low-temperature welding of the connection members.

[0108] In some embodiments, there may be flux in the weld layer. Flux refers to chemicals that aid or promote the welding process, provide protection, and prevent oxidation reactions during the welding process. The melting point of the flux is lower than that of the weld layer, so the flux can help increase the fluidity of the molten weld layer and better alloy the connection members and the grid line structure. In some embodiments, the flux includes inorganic flux, organic flux, and resin flux.

[0109] 16, the cross-sectional shape of the connection member 11 is circular in a plane perpendicular to the first direction X, but the cross-sectional shape of the connection member 11 is not limited to this example. In other embodiments, the cross-sectional shape of the connection member 11 in a plane perpendicular to the first direction X may be rectangular, elliptical, or polygonal.

[0110] In the case of the fixing film 12, the fixing film 12 is used to fix the connecting member 11 to the surface of the battery cell 10, and a bonding gap 103 is formed between the surface of the battery cell 10 and the side of the fixing film 12 and the connecting member 11. The fixing film 12 has a number of exhaust holes 104 in the bonding gap 103, and in some embodiments, the size of the exhaust hole 104 gradually decreases in the direction toward the bonding gap 103 of the fixing film 12. In the subsequent lamination process, the air in the bonding gap 103 expands due to heat, causing the fixing film 12 to separate, and the molten sealing layer 105 is more likely to flow between the connecting member 11 and the surface of the battery cell 10, causing insulation between the connecting member 11 and the grid line structure. As a result, by providing a number of exhaust holes 104 at the positions corresponding to the bonding gap 103 of the fixing film 12, the air in the bonding gap 103 can be exhausted from the exhaust holes 104 to the side of the fixing film 12 away from the battery cell 10 surface by pressing the sealing layer 105 in the subsequent lamination process. In addition, since the dimensions of the exhaust hole 104 gradually become smaller in the direction toward the adhesive gap 103 of the fixing film 12, even if the sealing layer 105 is melted during the lamination process and has a certain degree of fluidity, the sealing layer 105 cannot enter the adhesive gap 103 through the exhaust hole 104. As a result, the sealing layer 105 is prevented from penetrating into the adhesive gap 103 through the exhaust hole 104, and an insulating short circuit between the connecting member 11 and the grid line structure can be avoided.

[0111] In some embodiments, the exhaust hole 104 has a funnel-like shape in the direction toward the adhesive gap 103 of the fixing film 12, as shown in Fig. 16. Forming the funnel-like exhaust hole 104 helps air to be discharged from the adhesive gap 103 to the side of the fixing film 12 away from the adhesive gap 103, and at the same time, prevents the sealing layer 105 after melting from entering the adhesive gap 103 through the exhaust hole 104.

[0112] 18 shows a state before lamination processing of the photovoltaic module, and in some embodiments, as shown in FIG. 18, the fixing film 12 has a protruding portion 108 protruding in a tapered shape in a direction toward the adhesive gap 103 of the fixing film 12, and an opening is formed at an end of the protruding portion 108 close to the adhesive gap 103, and the protruding portion 108 serves as an exhaust hole 104. By forming the tapered protruding portion 108 on the fixing film 12, the molten sealing layer 105 is pressed along a direction toward the adhesive gap 103 of the fixing film 12, and a pressure difference is formed between the surface of the fixing film 12 on the side away from the battery cell 10 and the surface of the fixing film 12 on the side closer to the battery cell 10, which helps to exhaust the air in the adhesive gap 103 from the exhaust hole 104 to the side away from the adhesive gap 103 of the fixing film 12.

[0113] In some embodiments, the fixing film 12 may have a single layer structure or a multi-layer structure. For example, in some embodiments, the fixing film 12 may have a two-layer structure. Specifically, as shown in FIG. 19 , FIG. 19 shows the state before lamination processing of the photovoltaic module, and the fixing film 12 may include a first fixing film 121 that covers the surface of the connecting member 11 and covers the surfaces of the battery cells 10 on both sides of the connecting member 11 perpendicular to the first direction X, and a second fixing film 122 that covers the surface of the first fixing film 121.

[0114] In the case of the first fixing film 121, the material of the first fixing film 121 includes a material with a certain viscosity, such as ethylene vinyl acetate copolymer (EVA), acrylate, polyethylene (PE), etc., which can enhance the fixing effect of the connecting member and prevent the connecting member from shifting in position during lamination molding.

[0115] In the case of the second fixing film 122, the material of the second fixing film 122 may be a material such as polyethylene terephthalate (PET). Since the material constituting the sealing layer has a certain fluidity, during the lamination molding process, the sealing layer may penetrate between the connection member and the surface of the battery cell, which may cause an insulating short circuit between the connection member and the grid line structure, and the second fixing film can be used as an isolation protection layer between the connection member and the sealing layer.

[0116] 19, in some embodiments, the first fixing film 121 has a first opening 212 at a location corresponding to the adhesive gap 103, and the second fixing film 122 has a second opening 222 at a location corresponding to the adhesive gap 103, and the first opening 212 and the second opening 222 together form an exhaust hole 104, where the size of the first opening 212 is smaller than that of the second opening 222. During the lamination process, the gas in the adhesive gap 103 can be exhausted from the first opening 212 to the side of the fixing film 12 away from the battery cell 10 because the size requirement of the first opening 212 is low. On the other hand, if the molten sealing layer 105 has a high degree of adhesion and is less likely to penetrate into the first opening 212 than into the second opening 222, the molten sealing layer 105 can apply pressure to the adhesive gap 103 in the direction toward the adhesive gap 103 of the fixing film 12, but cannot penetrate into the adhesive gap 103 through the first opening 212. As a result, the molten sealing layer 105 creates a pressure difference at a location corresponding to the adhesive gap 103 of the fixing film 12, and the air in the adhesive gap 103 can be exhausted through the exhaust hole 104, but the sealing layer 105 cannot enter the adhesive gap 103, so that the gas in the adhesive gap 103 is completely exhausted, and the fixing film 12 can be attached to the surface of the connecting member 11 and the surface of the battery cell 10, and can also be attached to the boundary between the battery cell 10 and the connecting member 11.

[0117] In some embodiments, the first opening 212 and the second opening 222 are both funnel-shaped in the direction toward the adhesive gap 103 of the fixing film 12. Because the dimension of the first opening 212 is smaller than that of the second opening 222, the sealing layer 105 melted during lamination can form a pressure difference at the location corresponding to the adhesive gap 103 of the fixing film 12, and because the first opening 212 and the second opening 222 are both funnel-shaped, the pressure difference can be uniformly transferred, and the dimension difference between the first opening 212 and the second opening 222 is too large to prevent the second opening 222 from being pushed open by the pressure of the molten sealing layer 105, which causes the molten sealing layer 105 to penetrate into the adhesive gap 103, and thus the molten sealing layer 105 to flow between the connecting member 11 and the surface of the battery cell 10, resulting in insulation between the connecting member 11 and the grid line structure.

[0118] In some embodiments, the fixing film may have a three-layer structure, a five-layer structure, or a ten-layer structure, and the fixing film is constituted by a plurality of stacked sub-fixing films, each of which has an opening in the adhesive gap, and the openings of the plurality of sub-fixing films together form an exhaust hole, and the size of the opening in the sub-fixing films of the plurality of layers gradually decreases in the direction toward the adhesive gap of the fixing film, and the size of the exhaust hole gradually decreases along the direction toward the adhesive gap of the fixing film. Thus, during lamination, the sealing layer can form a gradually changing pressure difference at the exhaust hole along the direction toward the adhesive gap of the fixing film, which helps the air in the adhesive gap to be exhausted to the side away from the adhesive gap of the fixing film through the exhaust hole, and at the same time, can prevent the sealing layer from entering the adhesive gap through the exhaust hole.

[0119] In some embodiments, the area of ​​the exhaust hole 104 on the surface of the fixing film 12 away from the battery cell 10 is a first area, and the area of ​​the exhaust hole 104 on the surface of the fixing film 12 closer to the battery cell 10 is a second area, and the ratio of the first area to the second area is in the range of 2 to 20. As can be understood, the larger the ratio of the first area to the second area, the larger the dimensional change of the exhaust hole 104 along the direction toward the adhesive gap 103 of the fixing film 12. This increases the pressure difference applied to the exhaust hole 104 by the molten sealing layer 105 during the lamination process, which in turn causes the side of the exhaust hole 104 closer to the battery cell 10 to be pushed open by the molten sealing layer 105, which tends to cause the molten sealing layer 105 to penetrate into the adhesive gap 103. The smaller the ratio of the first area to the second area, the smaller the dimensional change of the exhaust hole 104 along the direction toward the adhesive gap 103 of the fixing film 12. As a result, during lamination processing, the smaller the pressure difference applied to the exhaust hole 104 by the molten sealing layer 105, the more likely the side of the exhaust hole 104 remote from the battery cell 10 will be blocked by the molten sealing layer 105, which in turn makes it less favorable for the air in the adhesive gap 103 to be discharged to the side remote from the adhesive gap 103 of the fixing film 12. Therefore, the ratio between the first area and the second area needs to be appropriately adjusted according to the actual dimensions of the adhesive gap 103 so that the air in the adhesive gap 103 is discharged to the side remote from the adhesive gap 103 of the fixing film 12 and the exhaust hole 104 is prevented from being deformed by the pressure difference caused by the molten sealing layer 105.

[0120] In some embodiments, the second area is in the range of 3 μm 2 ~700μm 2 Specifically, the second area is 3 μm 2 , 30μm 2 , 80μm 2 , 100μm 2 , 200μm 2 , 500μm 2 or 700 μm 2As can be understood, the second area is the dimension of the side of the exhaust hole 104 closer to the battery cell 10, and the larger the dimension of the second area, the faster the exhaust speed of the air in the corresponding adhesive gap 103, but if the dimension is too large, it is more likely that the molten sealing layer 105 will enter the adhesive gap 103. The smaller the dimension of the second area, the more disadvantageous it is for the air in the adhesive gap 103 to be exhausted to the side of the fixing film 12 away from the adhesive gap 103. Therefore, the dimension of the second area needs to be adjusted within an appropriate range so that the air in the adhesive gap 103 can be easily exhausted while preventing the molten sealing layer 105 from entering the adhesive gap 103 through the exhaust hole 104.

[0121] In some embodiments, the distance between the exhaust holes along the first direction ranges from 1 mm to 10 mm, and specifically, the distance between the exhaust holes may be 1 mm, 1.2 mm, 2.2 mm, 3.3 mm, 4.4 mm, 5.5 mm, 6.6 mm, 7.7 mm, 8.8 mm, or 10 mm. As can be seen, both the connection member and the fixing film extend along the first direction, and the corresponding adhesive gap also extends along the first direction, and the closer the distance between the exhaust holes along the first direction, the faster the air discharge speed in the adhesive gap. However, if the distance is too close, the fixing film between the exhaust holes will be pushed and deformed by the molten sealing layer, causing deformation of the exhaust holes, which in turn tends to cause the sealing layer to penetrate into the adhesive gap through the exhaust holes. Thus, it is necessary to select the distance between the exhaust holes within a suitable range to increase the discharge speed of the air in the adhesive gap and avoid the fixing film and the exhaust holes being deformed due to the distance between the exhaust holes being too close.

[0122] In some embodiments, in the direction perpendicular to the surface of the battery cell 10, the height from the exhaust hole 104 to the surface of the battery cell 10 is greater than half the height of the connection member 11. That is, in the direction perpendicular to the surface of the battery cell 10, the exhaust hole 104 is located in the upper half of the connection member 11, and during the lamination process, the fixing film 12 gradually adheres to the side of the connection member 11, and the angle between the exhaust hole 104 and the surface of the battery cell 10 becomes smaller and smaller. This makes it difficult for the molten sealing layer 15 to penetrate into the adhesive gap 103, which helps to prevent the molten sealing layer 105 from penetrating into the adhesive gap 103 through the exhaust hole 104.

[0123] In the case of the encapsulation layer 105, in some embodiments, the encapsulation layer 105 includes a first encapsulation layer and a second encapsulation layer, where the first encapsulation layer covers either the front or back surface of the battery cell, and the second encapsulation layer covers the other of the front or back surface of the battery cell, and specifically, at least one of the first encapsulation layer or the second encapsulation layer may be an organic encapsulation film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene-octene copolymer (POE) adhesive film, or a polyvinyl butyral (PVB) adhesive film.

[0124] For the cover plate 106, in some embodiments, the cover plate 106 may be a cover plate with a light-transmitting function, such as a glass cover plate, a plastic cover plate, etc. In some embodiments, the surface of the cover plate facing the sealing layer may be an uneven surface, which can improve the utilization rate of the incident light. In some embodiments, the cover plate includes a first cover plate and a second cover plate, where the first cover plate faces the first sealing layer, and the second cover plate faces the second sealing layer.

[0125] In the photovoltaic module according to the embodiment of the present application, a plurality of battery cells 10 are electrically connected via the connecting members 11, and in any battery cell 10, each connecting member 11 corresponds to one fixing film 12, which covers the surface of the connecting member 11 and a part of the surface of the battery cell 10 on both sides of the connecting member 11 perpendicular to the first direction X, and fixes the connecting member 11 to the surface of the battery cell 10. In addition, the fixing film 12 can be an isolation layer between the connecting member 11 and the sealing layer 105, and during the sealing process, the fixing film 12 can prevent the molten sealing layer 105 from flowing between the connecting member 11 and the surface of the battery cell 10, and thus can prevent the insulating between the connecting member 11 and the grid line structure of the battery cell 10 caused by the molten sealing layer 105. Here, there is an angle α between the fixing film 12 located on at least one side of the connecting member 11 and the surface of the battery cell 10, and this angle α is formed so as to surround the adhesive gap 103 together with the side of the connecting member 11. An exhaust hole 104 is provided at a location corresponding to the adhesive gap 103 in the fixing film 12, which helps to discharge the air in the adhesive gap 103 through the exhaust hole 104 to the side of the fixing film 12 away from the surface of the battery cell 10 in the subsequent lamination process, thereby preventing the air in the adhesive gap 103 from expanding due to heat and causing the fixing film 12 to detach, thereby improving the stability of the fixing film 12 and increasing the yield of the photovoltaic module.

[0126] According to some embodiments of the present application, in another embodiment of the present application, a method for manufacturing a photovoltaic module is provided, which is used to manufacture a sealed photovoltaic module by stacking the photovoltaic modules, and can increase the yield of the photovoltaic module. Note that for the same or corresponding parts as those of the above embodiments, the corresponding descriptions of the above embodiments can be referred to, and there is no need to repeat the description here.

[0127] FIG. 20 is a flow chart corresponding to the manufacturing method of the other photovoltaic module in one embodiment of the present application, and hereinafter, the manufacturing method of the photovoltaic module in this embodiment will be described in detail with reference to the drawings.

[0128] As shown in FIG. 20, the method for manufacturing a photovoltaic module includes: A step S1 of providing a plurality of battery cells, the battery cells being arranged along a first direction; A step S2 of fixing a plurality of connection members to a surface of the battery cells, the connection members extending along a first direction, and adjacent battery cells being electrically connected via the connection members; Step S3: covering a fixing film on a surface of each connecting member, the fixing film further covering the surfaces of the battery cells on both sides of the connecting member perpendicular to the first direction, where there is an included angle between the fixing film located on at least one side of the connecting member and the surfaces of the battery cells, and the included angle is formed together with the side of the connecting member to surround the adhesive gap; A step S4 of forming a plurality of exhaust holes at locations corresponding to the adhesive gaps of the fixing film; The method includes step S5 of laying and laminating a sealing layer and a cover plate, so that the sealing layer covers the surface of the fixing film and also covers the surfaces of the battery cells exposed from the fixing film, and the cover plate covers the surface of the sealing layer away from the battery cells.

[0129] In the embodiment of the present application, the method for manufacturing a photovoltaic module electrically connects a plurality of battery cells through a connecting member, and in any battery cell, each connecting member corresponds to a fixing film, and the fixing film covers a surface of the connecting member and a part of the surface of the battery cell on both sides of the connecting member perpendicular to a first direction, so as to fix the connecting member to the surface of the battery cell. In addition, the fixing film can be an isolation layer between the connecting member and the sealing layer, and during lamination, the fixing film can prevent the molten sealing layer from flowing between the connecting member and the surface of the battery cell, and thus prevent the insulating between the connecting member and the grid lines on the battery cell by the molten sealing layer. Furthermore, by forming an angle between the fixing film located on at least one side of the connecting member and the surface of the battery cell, and this angle is formed so as to surround the adhesive gap together with the side of the connecting member, and by forming multiple exhaust holes at locations corresponding to the adhesive gaps in the fixing film, in the subsequent stacking molding process, it helps to discharge the air located in the adhesive gap through the exhaust holes to the side of the fixing film away from the surface of the battery cell, thereby preventing the air in the adhesive gap from expanding due to heat and causing the fixing film to detach, improving the stability of the fixing film and ultimately increasing the yield of the photovoltaic module.

[0130] Accordingly, the following items are protected in the embodiments of the present application:

[0131] 1. A photovoltaic module comprising: A plurality of battery cells arranged along a first direction; a plurality of connection members extending along the first direction, the connection members being located on surfaces of the battery cells and electrically connecting the adjacent battery cells via the connection members; a plurality of fixing films, each of which covers a surface of one of the connection members and covers the surfaces of the battery cells on both sides of the connection member perpendicular to the first direction, wherein an included angle is formed between the fixing film located on at least one side of the connection member and the surface of the battery cell, the included angle being formed so as to surround an adhesive gap together with a side surface of the connection member, the fixing film having a plurality of exhaust holes at locations corresponding to the adhesive gap, and an orthogonal projection of the exhaust holes on the surface of the battery cell and an orthogonal projection of the connection member on the surface of the battery cell do not overlap; a sealing layer that covers a surface of the fixing film and covers a surface of the battery cell exposed from the fixing film; a cover plate covering a surface of the sealing layer remote from the battery cell.

[0132] 2. According to the photovoltaic module described in paragraph 1, the size of the exhaust hole gradually decreases along the direction toward the adhesive gap of the fixing film.

[0133] 3. According to the photovoltaic module described in paragraph 1, the fixing film has a tapered protrusion in a direction toward the adhesive gap, and an opening is provided at the end of the protrusion close to the adhesive gap, and the protrusion serves as the exhaust hole.

[0134] 4. According to the photovoltaic module described in paragraph 1, the fixing film includes a first fixing film that covers the surface of the connecting member and covers the surfaces of the battery cells on both sides of the connecting member perpendicular to the first direction, and a second fixing film that covers the surface of the first fixing film, and a first opening is provided at a location corresponding to the adhesive gap of the first fixing film, and a second opening is provided at a location corresponding to the adhesive gap of the second fixing film, and the first opening and the second opening together constitute the exhaust hole, and the dimension of the first opening is smaller than that of the second opening.

[0135] 5. According to the photovoltaic module described in item 4, the first opening and the second opening each have a funnel shape in the direction toward the adhesive gap of the fixing film.

[0136] 6. According to the photovoltaic module described in paragraph 1, the area of ​​the exhaust hole on the surface of the fixing film away from the battery cell is a first area, and the area of ​​the exhaust hole on the surface of the fixing film closer to the battery cell is a second area, and the range of the ratio of the first area to the second area is 2 to 20.

[0137] 7. According to the photovoltaic module described in paragraph 6, the second area range is 3 μm 2 ~700μm 2 It is.

[0138] 8. According to the photovoltaic module described in paragraph 1, the distance between the exhaust holes along the first direction is in the range of 1 mm to 10 mm.

[0139] 9. According to the photovoltaic module described in paragraph 1, the height from the exhaust hole to the surface of the battery cell in the direction perpendicular to the surface of the battery cell is greater than half the height of the connection member.

[0140] 10. A method for manufacturing a photovoltaic module, comprising: Providing a plurality of battery cells, the battery cells being arranged along a first direction; a plurality of connection members are fixed to surfaces of the battery cells, the connection members extend along the first direction, and adjacent battery cells are electrically connected via the connection members; A fixing film is covered on the surface of each of the connection members, and the fixing film further covers the surfaces of the battery cells on both sides of the connection members perpendicular to the first direction, where an included angle is formed between the fixing film located on at least one side of the connection members and the surfaces of the battery cells, and the included angle is formed to surround an adhesive gap together with a side surface of the connection members; forming a plurality of exhaust holes at locations of the fixing film corresponding to the adhesive gap; The method includes laying a sealing layer and a cover plate and laminating them, the sealing layer covering a surface of the fixing film and covering a surface of the battery cell exposed from the fixing film, and the cover plate covering a surface of the sealing layer away from the battery cell.

[0141] As can be understood by those skilled in the art, the above embodiments are specific examples for implementing the present invention, but in practical application, various changes in form and details can be made without departing from the spirit and scope of the present invention. Those skilled in the art can make various changes and modifications without departing from the scope of the present invention, and therefore the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for manufacturing a photovoltaic module, comprising the steps of: providing a plurality of battery cells, each of the battery cells including a grid line structure arranged in a spaced relationship along a first direction; providing a plurality of connection members arranged at intervals along a second direction, the connection members being located on a surface of the battery cells and electrically connected to adjacent battery cells; providing a plurality of composite films, the composite films covering a surface of the connection member, and both sides of the composite films covering a surface of the battery cell along the second direction, the composite films including a first layer and a second layer, the first layer being located between the second layer and the connection member; After providing a plurality of composite films, an included angle is formed between the composite film located on at least one side of the connection member and a surface of the battery cell, and the included angle is formed to surround an adhesive gap together with a side surface of the connection member; The method for manufacturing the photovoltaic module further comprises: forming a plurality of exhaust holes in the composite films at locations corresponding to the adhesive gaps after providing a plurality of composite films and before providing a sealing layer; A method for manufacturing a photovoltaic module comprising the steps of:

2. The step of producing the composite film includes: Uniformly mixing the raw materials of the first layer according to a compounding ratio and extruding them by an extrusion device to form a first raw material; uniformly mixing the raw materials of the second layer according to a compounding ratio and extruding them by an extrusion device to form a second raw material; pouring either the first raw material or the second raw material into a molding device according to a blending ratio to form an initial film; co-extrusion compounding, pouring the other of the first raw material and the second raw material into the molding device, and forming the composite film by screw extrusion compounding; The method for manufacturing a photovoltaic module according to claim 1 .

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