Photovoltaic module and method of manufacturing same

Abstract

To provide a photovoltaic module and a method for manufacturing the same that are advantageous in improving the efficiency and yield.SOLUTION: A photovoltaic module includes: an optical connection member 120 that has a first end portion 1201 positioned on a front surface of a first battery cell of adjacent battery cells 100 and a second end portion 1202 positioned on a rear surface of a second battery cell of the adjacent battery cells 100, where the first end portion 1201 is connected in contact with a plurality of grid lines 110 on the front surface of the first battery cell, and where the second end portion 1202 is connected in contact with the plurality of grid lines 110 on the rear surface of the second battery cell; and an encapsulation layer 130 comprising a first encapsulation sub-layer 131 and a second encapsulation sub-layer 132 that are sequentially arranged along a direction away from the battery cells 100, where the flowability of the first encapsulation sub-layer 131 is lower than that of the second encapsulation sub-layer 132.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

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

[0002] With the development of photovoltaic power generation technology, in the manufacturing of photovoltaic cells or photovoltaic modules, how to improve the efficiency of photovoltaic cells and increase the yield of photovoltaic cells while saving manufacturing costs has become an important issue.

[0003] As an important component of a solar cell, gridlines are used to collect and extract electrons generated by the photovoltaic effect, while PV ribbons are used to connect the cells in a photovoltaic module. The arrangement of gridlines and PV ribbons, the soldering quality of the PV ribbons and gridlines, the selection of PV ribbon and gridline materials, the soldering method of the PV ribbons and gridlines, and the adhesive film above the PV ribbons all have some impact on the photoelectric conversion efficiency of the cell, the efficiency of the photovoltaic module, the yield of the photovoltaic module, and the lifespan of the photovoltaic module. Currently, the installation methods of gridlines, PV ribbons, and adhesive films in photovoltaic modules need to be improved. Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments of the present application provide a photovoltaic module and a manufacturing method thereof that are advantageous in improving at least the efficiency and yield of the photovoltaic module. [Means for solving the problem]

[0005] According to some embodiments of the present application, one aspect of the embodiment of the present application provides a photovoltaic module including: a plurality of battery cells, each having a plurality of grid lines on a surface thereof; connection members, each connecting adjacent battery cells, each having a first end located on a front surface of a first battery cell among the adjacent battery cells and a second end located on a back surface of a second battery cell among the adjacent battery cells, the first end being in contact with and connected to the plurality of grid lines on the front surface of the first battery cell, and the second end being in contact with and connected to the plurality of grid lines on the back surface of the second battery cell; and a sealing layer including at least a first sealing sublayer and a second sealing sublayer sequentially arranged along a direction away from the battery cells, the first sealing sublayer being close to the connection members and portions of the battery cells not covered by the connection members, and the second sealing sublayer being located on a surface of the first sealing sublayer away from the battery cells, wherein the fluidity of the first sealing sublayer is lower than that of the second sealing sublayer.

[0006] In some embodiments, the ratio of the ML value of the first sealing sub-layer to the ML value of the second sealing sub-layer is between 1.5 and 8.5.

[0007] In some embodiments, the first encapsulating sub-layer has an ML value between 0.4 dN·m and 0.85 dN·m and / or the second encapsulating sub-layer has an ML value between 0.1 dN·m and 0.3 dN·m.

[0008] In some embodiments, the battery pack further includes adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the grid lines.

[0009] In some embodiments, the first sealing sub-layer and the second sealing sub-layer are a unitary structure.

[0010] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the maximum thickness of the connection member is 0.4-1 in a direction from the battery cell toward the sealing layer.

[0011] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the thickness of the second sealing sub-layer in a direction from the battery cell toward the sealing layer is between 0.3 and 1.5.

[0012] In some embodiments, the sealing layer further includes a third sealing sublayer disposed on a surface of the second sealing sublayer away from the battery cell, wherein the fluidity of the third sealing sublayer is higher than the fluidity of the first sealing sublayer and the fluidity of the second sealing sublayer.

[0013] In some embodiments, the ratio of the ML value of the first sealing sub-layer to the ML value of the second sealing sub-layer is 1.1 to 3, and the ratio of the ML value of the second sealing sub-layer to the ML value of the third sealing sub-layer is 1.1 to 4.

[0014] In some embodiments, the first sealing sub-layer has an ML value between 0.4 dN·m and 0.85 dN·m, the second sealing sub-layer has an ML value between 0.3 dN·m and 0.4 dN·m, and / or the third sealing sub-layer has an ML value between 0.1 dN·m and 0.3 dN·m.

[0015] In some embodiments, the ratio of the thickness of the first encapsulating sub-layer to the thickness of the second encapsulating sub-layer is 1-4 in a direction from the battery cell toward the encapsulating layer.

[0016] In some embodiments, the ratio of the thickness of the second sealing sub-layer to the thickness of the third sealing sub-layer in a direction from the battery cell toward the sealing layer is between 0.2 and 0.7.

[0017] In some embodiments, the material of the first sealing sub-layer and the material of the second sealing sub-layer are the same.

[0018] In some embodiments, the material of the first sealing sub-layer, the material of the second sealing sub-layer, and the material of the third sealing sub-layer are the same.

[0019] According to some embodiments of the present application, in another form of the embodiments of the present application, there is further provided a method for manufacturing the photovoltaic module of the above form, the method including: providing battery cells; providing a plurality of connection members by placing a first end of each connection member on a front surface of a first battery cell among adjacent battery cells and a second end of each connection member on a back surface of a second battery cell among the adjacent battery cells; providing a sealing layer by placing a first sealing sub-layer of each sealing layer so as to be close to the plurality of connection members and portions of the battery cells not covered by the connection members and placing a second sealing sub-layer on a surface of the first sealing sub-layer away from the battery cells, wherein the sealing layer includes the first sealing sub-layer and the second sealing sub-layer arranged sequentially along a direction away from the battery cells; and laminating the battery cells, the connection members, and the sealing layer at a predetermined temperature to fix the battery cells and the sealing layer.

[0020] In some embodiments, providing the connecting members further includes forming adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the gridlines.

[0021] In some embodiments, the sealing layer further includes a third sealing sublayer disposed on a surface of the second sealing sublayer away from the battery cell, wherein the fluidity of the third sealing sublayer is higher than the fluidity of the first sealing sublayer and the fluidity of the second sealing sublayer. [Brief explanation of the drawings]

[0022] One or more embodiments are illustratively described in corresponding figures in the accompanying drawings, but these illustrative descriptions are not intended to limit the embodiments, and unless otherwise specified, the figures in the accompanying drawings are not limited to scale. In order to more clearly explain the embodiments of the present application or the technical solutions of the prior art, the drawings to be used in the embodiments are briefly introduced below. It should be clear that the drawings in the following description are only some embodiments of the present application, and those skilled in the art can derive other drawings from these drawings without creative work. [Figure 1A]FIG. 1A is a diagram showing a cross-sectional structure of a photovoltaic module provided by one embodiment of the present application. [Figure 1B] FIG. 1B is a diagram showing a cross-sectional configuration of a photovoltaic module provided by another embodiment of the present application. [Figure 2] FIG. 2 is a diagram illustrating the configuration of grid lines and connecting members on the surface of a battery cell provided by one embodiment of the present application. [Figure 3] FIG. 3 is a schematic diagram of a vulcanization curve provided by one embodiment of the present application. [Figure 4A] FIG. 4A is a diagram showing a local cross-sectional configuration of a photovoltaic module before stacking provided by one embodiment of the present application. [Figure 4B] FIG. 4B is a diagram showing a local cross-sectional configuration of a photovoltaic module before lamination provided by another embodiment of the present application. [Figure 5] FIG. 5 is a diagram showing a configuration corresponding to the step of providing a battery cell in a method for manufacturing a photovoltaic module provided in one embodiment of the present application. [Figure 6] FIG. 6 is a diagram illustrating a configuration corresponding to the step of forming adhesive dots in the method for manufacturing a photovoltaic module provided in one embodiment of the present application. [Figure 7] FIG. 7 is a diagram illustrating a configuration corresponding to the step of fixing the connecting members using adhesive dots in the method for manufacturing a photovoltaic module according to an embodiment of the present application. [Figure 8A] FIG. 8A is a diagram illustrating a configuration corresponding to the step of providing an encapsulation layer in the method for manufacturing a photovoltaic module provided in one embodiment of the present application. [Figure 8B] FIG. 8B is a diagram illustrating a configuration corresponding to the step of providing an encapsulation layer in the method for manufacturing a photovoltaic module provided in another embodiment of the present application. [Figure 9A] FIG. 9A is a diagram showing a configuration corresponding to a photovoltaic module after a lamination process is performed in a method for manufacturing a photovoltaic module provided in an embodiment of the present application. [Figure 9B]FIG. 9B is a diagram showing a configuration corresponding to the photovoltaic module after a lamination process is performed in the method for manufacturing a photovoltaic module provided in another embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0023] According to the background art, it has been found that the installation methods of grid lines, PV ribbons and adhesive films in photovoltaic modules need to be improved.

[0024] Analysis shows that sunlight enters the battery through the surface of the battery cell, but the grid lines on the surface of the battery cell shield the battery cell, preventing the light energy irradiated on the metal electrode from being converted into electrical energy. From a light-shielding perspective, the thinner the grid lines, the better. However, since grid lines are used to conduct current, from a resistivity perspective, the thinner the grid lines, the smaller the conductive cross-sectional area and the greater the resistance loss. Therefore, the key to grid line design is to balance light shielding and conductivity. Furthermore, the paste used to make grid lines is typically made primarily of the expensive precious metal silver. Furthermore, during the process of connecting battery cells into a module, the main grid of one battery cell must be soldered to the main grid of the adjacent battery cell via the PV ribbon. Therefore, a thick main grid is usually required to ensure the connection between the PV ribbon and the main grid. This results in high material costs and increases the module manufacturing costs due to the thick main grid. Using PV ribbons, which have low material costs, instead of the main grid and connecting many thinner PV ribbons directly to the thin grid of the cell can not only reduce the manufacturing costs of the grid lines and PV ribbons, but also be advantageous in increasing the photoelectric conversion efficiency of the solar cell.

[0025] However, connecting conventional PV ribbons to grid lines requires soldering to form an alloy between the PV ribbons and grid lines. Conventional PV ribbons typically include a solder layer, the melting point of which is 183°C. During the actual soldering process, the soldering temperature must be at least 20°C higher than the melting point of the soldering agent. This requires high soldering temperatures to form an alloy between the PV ribbons and grid lines. High soldering temperatures can cause significant warping and deformation of the battery cells during soldering. Furthermore, hidden cracks are likely to occur in the battery cells after soldering, resulting in a high rate of chipping, which increases the module's repair rate and lowers yield. Therefore, low-temperature PV ribbons can be used to reduce soldering damage. Low-temperature PV ribbons typically form connections with the gridlines during lamination. However, during lamination, the temperature rises, causing the adhesive film located above the PV ribbons to become fluid. The fluid adhesive film is prone to flow between the PV ribbons and the gridlines before they are alloyed together, causing poor contact between the PV ribbons and the gridlines, which adversely affects the efficiency and yield of the photovoltaic module.

[0026] In order to solve the above problems, the present application provides a photovoltaic module and a manufacturing method thereof, in which the grid lines in the photovoltaic module may be thin grids on the cell surface, and the connecting members may be PV ribbons that are provided on the cell surface instead of the main grid and connect adjacent cells. By using the connecting members instead of the main grid, the installation of a thick main grid can be avoided, which is advantageous for reducing the cost of the photovoltaic module, while avoiding excessive shielding of the cell surface by the main grid, which is advantageous for improving the photoelectric conversion efficiency of the battery cells, and ultimately for improving the efficiency of the photovoltaic module. The encapsulation layer covers the surfaces of the battery cells and the connecting members to protect the battery cells. The encapsulation layer includes a first encapsulation sublayer adjacent to the surfaces of the battery cells and the connecting members and a second encapsulation sublayer away from the battery cells. The first encapsulation sublayer has lower fluidity than the second encapsulation sublayer, where both the first and second encapsulation sublayers are fluid at lamination temperatures. That is, the photovoltaic module is a photovoltaic module in the process of laminating. The lamination process refers to the process of laying connecting members on opposing surfaces of the battery cells, covering the connecting members and the surfaces of the battery cells not covered by the connecting members with encapsulation layers, and then laminating the battery cells, connecting members, and encapsulation layers at lamination temperatures. At lamination temperatures, the connecting members form an alloy with the grid lines located below the connecting members, further forming contact connections. If the encapsulation layer is in a scorched state at lamination temperatures, the encapsulation layer is in a fluid state. In order to prevent the sealing layer, which is in the scorched stage before the connection members and the grid lines form an alloy, from flowing between the connection members and the grid lines, thereby causing poor contact between the connection members and the grid lines, the first sealing sub-layer adjacent to the connection members and the battery cells is set to a low fluidity state. This is advantageous in preventing the first sealing sub-layer from flowing between the connection members and the grid lines, and further in preventing poor contact between the connection members and the grid lines, which is advantageous in improving the efficiency and yield of the photovoltaic module.In addition, the first sealing sub-layer is used to isolate the second sealing sub-layer, which has a relatively high fluidity, and the second sealing sub-layer, which has a high fluidity, is used to ensure a high degree of cross-linking throughout the sealing layer. This ensures that the sealing layer can effectively seal and protect the battery, increases the adhesive strength between the sealing layer and the cover plate, and is advantageous for extending the life of the photovoltaic module.

[0027] Specifically, in an embodiment of the present application, a photovoltaic module is provided, the photovoltaic module including: a plurality of battery cells, each having a plurality of grid lines on a surface thereof; and connection members connecting adjacent battery cells, each connection member having a first end located on a front surface of a first battery cell among the adjacent battery cells and a second end located on a back surface of a second battery cell among the adjacent battery cells, the first end being in contact with and connected to the plurality of grid lines on the front surface of the first battery cell and the second end being in contact with and connected to the plurality of grid lines on the back surface of the second battery cell; and a sealing layer including a first sealing sublayer and a second sealing sublayer sequentially arranged along a direction away from the battery cells, the first sealing sublayer being close to the connection members and portions of the battery cells not covered by the connection members, and the second sealing sublayer being located on a surface of the first sealing sublayer away from the battery cells, wherein the fluidity of the first sealing sublayer is lower than that of the second sealing sublayer.

[0028] In some embodiments, the ratio of the ML value of the first sealing sub-layer to the ML value of the second sealing sub-layer is between 1.5 and 8.5.

[0029] In some embodiments, the first encapsulating sub-layer has an ML value between 0.4 dN·m and 0.85 dN·m and / or the second encapsulating sub-layer has an ML value between 0.1 dN·m and 0.3 dN·m.

[0030] In some embodiments, the battery pack further includes adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the grid lines.

[0031] In some embodiments, the first sealing sub-layer and the second sealing sub-layer are a unitary structure.

[0032] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the maximum thickness of the connection member is 0.4-1 in a direction from the battery cell toward the sealing layer.

[0033] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the thickness of the second sealing sub-layer in a direction from the battery cell toward the sealing layer is between 0.3 and 1.5.

[0034] In some embodiments, the material of the first sealing sub-layer and the material of the second sealing sub-layer are the same.

[0035] According to some embodiments of the present application, in another aspect of the embodiment of the present application, there is further provided a method for manufacturing a photovoltaic module, the method including: providing a plurality of battery cells each having a plurality of grid lines on a surface thereof; providing connection members by placing a first end of each connection member on a front surface of a first battery cell among adjacent battery cells and a second end of each connection member on a back surface of a second battery cell among the adjacent battery cells; providing a sealing layer by placing a first sealing sub-layer of each sealing layer close to the plurality of connection members and portions of the battery cells not covered by the connection members and placing a second sealing sub-layer on a surface of the first sealing sub-layer away from the battery cells; and laminating the battery cells, the connection members, and the sealing layer at a predetermined temperature to fix the battery cells and the sealing layer, wherein a fluidity of the first sealing sub-layer at the predetermined temperature is lower than a fluidity of the second sealing sub-layer at the predetermined temperature.

[0036] In some embodiments, providing the connecting members further includes forming adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the gridlines.

[0037] The technical means provided by the embodiments of the present application have at least the following advantages: The grid lines may be thin grids on the cell surface, and the connecting members may be PV ribbons that are provided on the cell surface instead of the main grid and connect adjacent cells. Using connecting members instead of the main grid avoids the need for a thick main grid, which is advantageous for reducing the cost of the photovoltaic module, while avoiding excessive shielding of the cell surface by the main grid, which is advantageous for improving the photoelectric conversion efficiency of the battery cells and ultimately for improving the efficiency of the photovoltaic module. The encapsulation layer covers the surfaces of the battery cells and connecting members to protect the battery cells. It includes a first encapsulation sublayer adjacent to the battery cell surfaces and connecting members and a second encapsulation sublayer away from the battery cells. The first encapsulation sublayer has lower fluidity than the second encapsulation sublayer, where both the first and second encapsulation sublayers are fluid at lamination temperatures. That is, the photovoltaic module is a photovoltaic module in the process of laminating. The lamination process refers to the process of laying connecting members on the surfaces of the battery cells, covering the connecting members and the exposed surfaces of the battery cells with an encapsulation layer, and then laminating the battery cells, connecting members, and encapsulation layer. The lamination process involves a certain lamination temperature, where the connecting members and the grid lines underneath the connecting members form an alloy and further establish contact. Generally, when the encapsulation layer is in a scorched state at lamination temperatures, the encapsulation layer is in a fluid state. To prevent the scorched sealing layer from flowing between the connecting member and the grid line before the two form an alloy, which could result in poor contact between the connecting member and the grid line, the first sealing sub-layer adjacent to the connecting member and the battery cell is set to a low fluidity state. This prevents the first sealing sub-layer from flowing between the connecting member and the grid line, which could result in poor contact between the connecting member and the grid line, and is advantageous for improving the efficiency and yield of the photovoltaic module. Furthermore, the first sealing sub-layer is used to isolate the second sealing sub-layer, which has a relatively high fluidity, and the second sealing sub-layer, which has a high fluidity, is used to ensure a high degree of cross-linking throughout the sealing layer. This ensures that the sealing layer effectively seals and protects the battery, increases the adhesive strength between the sealing layer and the cover plate, and is advantageous for extending the life of the photovoltaic module.

[0038] According to some embodiments of the present application, in another aspect of the embodiment of the present application, there is further provided a photovoltaic module, the photovoltaic module including a plurality of battery cells each having a plurality of grid lines on a surface thereof, and a connection member connecting adjacent battery cells, each connection member having a first end located on a front surface of a first battery cell among the adjacent battery cells and a second end located on a back surface of a second battery cell among the adjacent battery cells, the first end being in contact with and connected to the plurality of grid lines on the front surface of the first battery cell, and the second end being in contact with and connected to the plurality of grid lines on the back surface of the second battery cell. The connecting member contacts and connects with several grid lines and includes a first sealing sublayer, a second sealing sublayer, and a third sealing sublayer that are sequentially arranged along a direction away from the battery cell, wherein the first sealing sublayer is close to the connecting member and a portion of the battery cell that is not covered by the connecting member, the second sealing sublayer is located on a surface of the first sealing sublayer that is away from the battery cell, and the third sealing sublayer is located on a surface of the second sealing sublayer that is away from the battery cell, and wherein the fluidity of the third sealing sublayer, the fluidity of the second sealing sublayer, and the fluidity of the first sealing sublayer sequentially decrease.

[0039] In some embodiments, the ratio of the ML value of the first sealing sub-layer to the ML value of the second sealing sub-layer is 1.1-3.

[0040] In some embodiments, the ratio of the ML value of the second encapsulating sub-layer to the ML value of the third encapsulating sub-layer is 1.1-4.

[0041] In some embodiments, the first sealing sub-layer has an ML value between 0.4 dN·m and 0.85 dN·m and / or the second sealing sub-layer has an ML value between 0.3 dN·m and 0.4 dN·m.

[0042] In some embodiments, the ML value of the third encapsulating sub-layer is between 0.1 dN·m and 0.3 dN·m.

[0043] In some embodiments, the battery pack further includes adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the grid lines.

[0044] In some embodiments, the first sealing sub-layer, the second sealing sub-layer, and the third sealing sub-layer are a unitary structure.

[0045] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the maximum thickness of the connection member is 0.4-1 in a direction from the battery cell toward the sealing layer.

[0046] In some embodiments, the ratio of the thickness of the first sealing sub-layer to the thickness of the second sealing sub-layer is 1-4 in a direction from the battery cell toward the sealing layer.

[0047] In some embodiments, the ratio of the thickness of the second sealing sub-layer to the thickness of the third sealing sub-layer in a direction from the battery cell toward the sealing layer is between 0.2 and 0.7.

[0048] In some embodiments, the material of the first sealing sub-layer, the material of the second sealing sub-layer, and the material of the third sealing sub-layer are the same.

[0049] According to some embodiments of the present application, in another aspect of the embodiment of the present application, there is further provided a method for manufacturing a photovoltaic module, the method including: providing a plurality of battery cells, each having a plurality of grid lines on a surface thereof; providing connection members by placing a first end of each connection member on a front surface of a first battery cell among adjacent battery cells and a second end of each connection member on a back surface of a second battery cell among the adjacent battery cells; providing a sealing layer by placing a first sealing sub-layer of each sealing layer close to the plurality of connection members and portions of the battery cells not covered by the connection members, placing a second sealing sub-layer on a surface of the first sealing sub-layer remote from the battery cells, and placing a third sealing sub-layer on a surface of the second sealing sub-layer remote from the battery cells; and laminating the battery cells, the connection members, and the sealing layers at a predetermined temperature to fix the battery cells and the sealing layers, wherein a fluidity of the third sealing sub-layer at the predetermined temperature, a fluidity of the second sealing sub-layer at the predetermined temperature, and a fluidity of the first sealing sub-layer at the predetermined temperature are sequentially reduced.

[0050] In some embodiments, providing the connecting members further includes forming adhesive dots located between some of the battery cells and the connecting members and located on surfaces of the battery cells other than the gridlines.

[0051] The technical means provided by the embodiments of the present application have at least the following advantages: The grid lines may be thin grids on the cell surface, and the connecting members may be PV ribbons that are provided on the cell surface instead of the main grid and connect adjacent cells. Using the connecting members instead of the main grid avoids the need for a thick main grid, which is advantageous for reducing the cost of the photovoltaic module, while avoiding excessive shielding of the cell surface by the main grid, which is advantageous for improving the photoelectric conversion efficiency of the cells and ultimately the efficiency of the photovoltaic module. The encapsulating layer covers the surfaces of the battery cells and the connecting members and is used to protect the battery cells. It includes at least a first encapsulating sublayer, a second encapsulating sublayer, and a third encapsulating sublayer that are sequentially arranged in a direction away from the battery cells, and the fluidity of the third encapsulating sublayer, the fluidity of the second encapsulating sublayer, and the fluidity of the first encapsulating sublayer decrease sequentially, where the fluidity of the first encapsulating sublayer, the fluidity of the second encapsulating sublayer, and the fluidity of the third encapsulating sublayer are all fluid at the lamination temperature, i.e., the photovoltaic module is a photovoltaic module during lamination. The lamination process refers to the process of laying connecting members on the surfaces of battery cells, covering the connecting members and the exposed surfaces of the battery cells with encapsulating layers, and then laminating the battery cells, connecting members, and encapsulating layers. The lamination process requires a certain lamination temperature, at which the connecting members and the grid lines located below the connecting members form an alloy and further establish contact. Generally, if the encapsulating layer is in a scorched state at the lamination temperature, the encapsulating layer is in a fluid state. To prevent the scorched encapsulating layer from flowing between the connecting members and the grid lines before they form an alloy, which could cause poor contact between the connecting members and the grid lines, the first encapsulating sublayer adjacent to the connecting members and the battery cells is set to a low fluidity state. This prevents the first encapsulating sublayer from flowing between the connecting members and the grid lines, which could cause poor contact between the connecting members and the grid lines, and is advantageous for improving the efficiency and yield of photovoltaic modules.In addition, using the first sealing sub-layer to isolate the second and third sealing sub-layers, which have relatively high fluidity, and using the second sealing sub-layer as a bridge between the first and third sealing sub-layers, is advantageous for increasing the adhesive strength between the first and third sealing sub-layers; and the third sealing sub-layer, which has the highest fluidity, is advantageous for ensuring strong adhesive strength between the sealing layer and the cover plate, which is ultimately advantageous for extending the life of the photovoltaic module.

[0052] Hereinafter, each embodiment of the present application will be described in detail with reference to the accompanying drawings. However, as will be understood by those skilled in the art, although many technical details are proposed in each embodiment of the present application to help readers better understand the present application, the technical solution claimed for protection by the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

[0053] FIG. 1A is a diagram showing a cross-sectional configuration of a photovoltaic module provided by an embodiment of the present application, and FIG. 2 is a diagram showing the configuration of grid lines and connecting members on the surface of a battery cell provided by an embodiment of the present application.

[0054] 1A and 2, the photovoltaic module includes a plurality of battery cells 100 each having a plurality of grid lines 110 on two opposing surfaces thereof, and connection members 120 located on the surfaces of the battery cells 100, such that the connection members 120 connect adjacent battery cells 100, and the connection members 120 located on the grid lines 110 are in contact with and connected to the grid lines 110. That is, each connection member 120 has a first end 1201 located on the front surface of a first battery cell among the adjacent battery cells and a second end 1202 located on the back surface of a second battery cell among the adjacent battery cells, with the first end being in contact with and connected to the plurality of grid lines on the front surface of the first battery cell and the second end being in contact with and connected to the plurality of grid lines on the back surface of the second battery cell.

[0055] The battery cell 100 is used to absorb photons in incident light to generate electron-hole pairs. The electron-hole pairs are separated by the built-in electric field of the battery cell 103, and a potential is generated across a PN junction, thereby converting light energy into electrical energy. In some embodiments, one surface of the battery cell 100 is used as a light-receiving surface for absorbing incident light. In other embodiments, both surfaces of the battery cell 100 are used as light-receiving surfaces for absorbing incident light. In some embodiments, the battery cell 100 may be a crystalline silicon solar cell, such as a monocrystalline silicon solar cell or a polycrystalline silicon solar cell. As can be understood, in some embodiments, a photovoltaic module includes a plurality of battery cells 100. When the number of battery cells 100 is multiple, the battery cells 100 may be electrically connected as a whole or in multiple fragments (e.g., multi-fragments such as 1 / 2 equal cells, 1 / 3 equal cells, 1 / 4 equal cells, etc.) to form multiple cell strings, and the multiple cell strings may be electrically connected in series and / or parallel.

[0056] The battery cell 100 includes, but is not limited to, any one of a PERC battery (Passivated Emitter and Rear Cell), a PERT battery (Passivated Emitter and Rear Totally-diffused cell), a TOPCon battery (Tunnel Oxide Passivated Contact), and a HIT / HJT battery (Heterojunction Technology).

[0057] The battery cell 100 may include a substrate, which may be a silicon substrate. In some embodiments, the battery cell 100 may have opposing front and back surfaces 101, 102, and may have a metal paste printed on the front surface 101 and the back surface 102 to form grid lines 110 having a particular pattern.

[0058] In some embodiments, the plurality of battery cells 100 in the photovoltaic module are spaced apart and installed in parallel, and a connecting member 120 connects two opposing surfaces of two adjacent battery cells 100, respectively, to form an electrical connection between the two battery cells 100. For example, one end of each connecting member is provided on the front surface of one of the adjacent battery cells, and the other end of each connecting member is provided on the back surface of the other of the adjacent battery cells.

[0059] In some embodiments, the connecting member 120 may be a PV ribbon, and in a cross section perpendicular to the extension direction of the connecting member 120, the cross-sectional shape of the connecting member 120 may be any one of a circle, a rectangle, a trapezoid, or a triangle.

[0060] In some embodiments, the grid lines 110 may be thin grids on the surface of the battery cells 100, which are used to collect and conduct electrons generated by the photovoltaic effect. The connecting members 120 may be PV ribbons that are provided on the surface of the battery cells 100 instead of the main grids and connect adjacent battery cells 100. Using the connecting members 120 instead of the main grids avoids the need for thick main grids, which is advantageous for reducing the cost of the photovoltaic module, while avoiding excessive shielding of the surface of the battery cells 100 by the main grids, which is advantageous for improving the photoelectric conversion efficiency of the battery cells 100 and ultimately the efficiency of the photovoltaic module.

[0061] In some embodiments, as shown in FIG. 2 , the grid lines 110 may be thin grids on the surface of the battery cells 100, the connecting members 120 may be PV ribbons provided on the surface of the battery cells 100 instead of the main grid and for connecting adjacent battery cells 100, the plurality of grid lines 110 extending along a first direction X on the surface of the battery cells and spaced apart along a second direction Y, and the plurality of connecting members 120 extending along the second direction Y on the surface of the battery cells and spaced apart along the first direction X, where the first direction X intersects with the second direction Y.

[0062] In some embodiments, grid lines 110 may be main grids or thin grids. The thin grids are used to conduct current, and the main grids are used to collect and combine the current on the thin grids. Connecting members 120 are PV ribbons that connect to the main grids.

[0063] In addition, the connection members 120 in the embodiments of the present application are low-temperature PV ribbons, which form connections with the grid lines 110 during the lamination process, thereby avoiding excessively high soldering temperatures that would otherwise be required due to the use of high-temperature PV ribbons, and thus avoiding damage to the battery cells 100 caused by excessively high soldering temperatures, which is advantageous for reducing the repair rate of photovoltaic modules and improving the yield of photovoltaic modules.

[0064] In some embodiments, the connecting member 120 is a tin-coated metal PV ribbon, and the melting temperature of the tin layer is below 150°C, typically between 130°C and 150°C, which is advantageous for accommodating the lamination temperature of photovoltaic modules.

[0065] 1A , the photovoltaic module further includes a sealing layer 130 covering the surfaces of the battery cells 100 and the surfaces of the connection members 120, and the sealing layer 130 includes at least a first sealing sub-layer 131 and a second sealing sub-layer 132 sequentially arranged along a direction away from the battery cells 100, where the fluidity of the first sealing sub-layer 131 is lower than that of the second sealing sub-layer 132. The sealing layer 130 is used to seal and protect the battery cells, and may be an adhesive film.

[0066] In some embodiments, the sealing layer 130 is disposed on the front surface 101 and the back surface 102 of the battery cell 100, and is used to cover the connection members 120 on the surface of the battery cell 100, seal the battery cell 100, and bond the battery cell 100 to a cover plate (not shown).

[0067] The fluidity of the first sealing sub-layer 131 and the fluidity of the second sealing sub-layer 132 are both fluidity at the lamination temperature, that is, the photovoltaic module is a photovoltaic module in the process of lamination. The lamination process refers to the process of laying the connecting member 120 on the surface of the battery cell 100, covering the connecting member 120 and the surface of the battery cell 100 exposed from the connecting member 120 with the sealing layer 130, and then laminating the battery cell 100, the connecting member 120, and the sealing layer 130. There is a certain lamination temperature during the lamination process, and at the lamination temperature, the connecting member 120 and the connecting member 120 The first sealing sub-layer 131 adjacent to the connecting member 120 and the battery cell 100 forms an alloy with the underlying grid line 110, thereby forming a contact connection. When the encapsulating layer is in a scorched state at lamination temperatures, the encapsulating layer is in a fluid state. Setting the first sealing sub-layer 131 adjacent to the connecting member 120 and the battery cell 100 to a low fluidity state prevents the first sealing sub-layer 131 from flowing between the connecting member 120 and the grid line 110, which could cause poor contact between the connecting member 120 and the grid line 110, which is beneficial to improving the efficiency and yield of the photovoltaic module. Furthermore, the first sealing sub-layer 131 is used to isolate the second sealing sub-layer 132, which has a relatively high fluidity. The second sealing sub-layer 132, which has a high fluidity, is used to ensure that the encapsulating layer 130 has a high degree of cross-linking, which further ensures good sealing protection of the battery by the encapsulating layer 130 and increases the adhesive strength between the encapsulating layer 130 and the cover plate, which is beneficial to extending the life of the photovoltaic module.

[0068] The fluidity of the first sealing sublayer 131 can be represented by the ML (minimum torque) value of the first sealing sublayer 131, and the fluidity of the second sealing sublayer 132 can be represented by the ML value of the second sealing sublayer 132. The ML value is the lowest torque in the adhesive film vulcanization curve, and the lower the ML value, the higher the fluidity of the adhesive film before the crosslinking reaction during the lamination process. The higher the ML value, the lower the fluidity of the adhesive film before the crosslinking reaction during the lamination process.

[0069] The vulcanization curve is used to indicate the vulcanization performance of adhesive films. Vulcanization performance refers to the film's performance during the vulcanization process, which is the process that causes the vulcanization reaction in the film. The vulcanization reaction (crosslinking reaction) refers to the molecular chains of the adhesive film undergoing a chemical crosslinking reaction due to chemical or physical factors, forming a spatial network structure. The linear polymers in unvulcanized adhesive films are curled and in a state of free movement. When subjected to external forces, the linear polymers are easily displaced, i.e., exhibiting relatively large plastic flow. In vulcanized adhesive films, the soft linear polymers form a spatial network structure through crosslinking, which restricts the relative movement of the linear polymers to a certain extent, making them less susceptible to large displacements under external forces. This generates high stress and strength, and the physical, mechanical, and chemical properties are improved by vulcanization.

[0070] Generally, a vulcanization tester can be used to measure the change in the vulcanization performance of adhesive films during the vulcanization process.The working principle of the vulcanization tester is to place an adhesive film sample in a cavity in a compression mold, and then subject the adhesive film sample to a constant, small amplitude, and low frequency sinusoidal shear deformation continuously, and measure the shear stress with the load cell of the vulcanization tester, and express the shear stress in units of torque, and the recorded shear stress-time curve is the vulcanization curve.

[0071] Figure 3 is a schematic diagram of a vulcanization curve provided by one embodiment of the present application. As shown in Figure 3, the vulcanization process of an adhesive film can be divided into four stages: scorch stage, thermal vulcanization stage, flat vulcanization stage, and overvulcanization stage. The scorch stage corresponds to the induction period of the vulcanization reaction. During this period, crosslinking has not yet begun, the adhesive film remains fluid, and the adhesive film sample generates crosslinkable radicals. The thermal vulcanization stage is the vulcanization reaction (crosslinking reaction) stage, during which the adhesive film molecules gradually form a network structure, resulting in a rapid increase in the elasticity and strength of the adhesive film. During the flat vulcanization stage, the adhesive film has already reached an appropriate degree of crosslinking. During this period, the physical and mechanical properties of the adhesive film reach, approach, or achieve an optimal overall balance. During the overvulcanization stage, the crossbonds in the adhesive film rearrange, causing thermal decomposition of the crossbonds and molecular chains in the adhesive film, resulting in a decrease in the performance of the adhesive film.

[0072] As shown in FIG. 3, the minimum torque ML indicates the minimum shear stress value of the adhesive film before the start of the crosslinking reaction, that is, the maximum value of the adhesive film fluidity before the flat vulcanization stage (start of the crosslinking reaction) in the vulcanization process.

[0073] In some embodiments, as shown in FIG. 1B , the sealing layer may include a first sealing sublayer 131, a second sealing sublayer 132, and a third sealing sublayer 133 arranged sequentially along a direction away from the battery cell, where the fluidity of the third sealing sublayer 133 (which can be represented by the ML value of the third sealing sublayer 133), the fluidity of the second sealing sublayer 132, and the fluidity of the first sealing sublayer 131 decrease sequentially.

[0074] In this case, the first sealing sublayer 131 is used to isolate the second sealing sublayer 132 and the third sealing sublayer 133, which have relatively high fluidity, and the second sealing sublayer 132 is used as a bridge between the first sealing sublayer 131 and the third sealing sublayer 133, which is advantageous to increase the adhesive strength between the first sealing sublayer 131 and the third sealing sublayer 133. The third sealing sublayer 133, which has the highest fluidity, ensures strong adhesive strength between the sealing layer 130 and the cover plate, which is advantageous to extending the service life of the photovoltaic module.

[0075] In some embodiments, the encapsulating layer may include a first encapsulating sublayer, a second encapsulating sublayer, a third encapsulating sublayer, and a fourth encapsulating sublayer that are sequentially arranged in a direction away from the battery cell, and the fluidity of the fourth encapsulating sublayer, the fluidity of the third encapsulating sublayer, the fluidity of the second encapsulating sublayer, and the fluidity of the first encapsulating sublayer sequentially decrease. In the embodiments of the present application, the number of layers with different fluidities in the encapsulating layer is not particularly limited, as long as the fluidity of the multiple layers on the battery cell surface sequentially increases in a direction away from the battery cell.

[0076] In some embodiments, as shown in FIG. 1A, the first sealing sublayer 131 before lamination is a pre-crosslinked adhesive film, and the second sealing sublayer 132 before lamination is a non-pre-crosslinked adhesive film. The difference between a pre-crosslinked adhesive film and a non-pre-crosslinked adhesive film is whether a crosslinking reaction occurs between molecules within the adhesive film material before lamination. A crosslinking reaction refers to the process by which two or more molecules (typically linear polymers) bond together to form relatively stable molecules (conformal polymers) with a network structure. Typically, during lamination, after a certain lamination time at a certain lamination temperature, the adhesive film reaches a highly fluid state (scorch stage), during which the crosslinking agent in the adhesive film decomposes and generates radicals. Over time, the radicals induce bonds between long-chain molecules in the adhesive film, bonding and securing the adhesive film, battery cell, and cover plate. Because some molecules within the pre-crosslinked adhesive film have already undergone crosslinking before lamination, the fluidity of the pre-crosslinked adhesive film at the scorch stage is lower than the fluidity of a non-pre-crosslinked adhesive film at the scorch stage, and the fluidity of the pre-crosslinked adhesive film at the scorch stage depends on the proportion of molecules that have undergone crosslinking inside the pre-crosslinked adhesive film before lamination.

[0077] In other embodiments, as shown in FIG. 1B, the first sealing sublayer 131 before lamination is a pre-crosslinked adhesive film, the second sealing sublayer 132 before lamination is a pre-crosslinked adhesive film, and the third sealing sublayer 133 before lamination is a non-pre-crosslinked adhesive film.

[0078] 1A , in some embodiments, the first sealing sublayer 131 and / or the second sealing sublayer 132 may be a POE (ethylene octene copolymer) adhesive film. POE adhesive films are composed of saturated fatty acid chains and have good UV resistance, excellent heat resistance, and low temperature resistance. POE adhesive films have a wide operating temperature range, good light transmittance, excellent electrical insulation, high cost performance, and easy processing. In other embodiments, the first sealing sublayer 131 and / or the second sealing sublayer 132 may be an EVA adhesive film. EVA adhesive films are a common adhesive film whose main component is ethylene vinyl acetate copolymer (EVA), and the EVA adhesive film may contain small amounts of crosslinking agents, crosslinking aids, anti-aging agents, and other additives.

[0079] 1B, in some embodiments, at least one of first sealing sublayer 131, second sealing sublayer 132, and third sealing sublayer 133 may be a POE adhesive film. In other embodiments, at least one of first sealing sublayer 131, second sealing sublayer 132, and third sealing sublayer 133 may be an EVA adhesive film.

[0080] In some embodiments, at least two of the first sealing sub-layer 131, the second sealing sub-layer 132, and the third sealing sub-layer 133 are made of the same material.

[0081] For example, the material of the first sealing sublayer 131 is the same as the material of the second sealing sublayer 132. Making the materials of the first sealing sublayer 131 and the second sealing sublayer 132 the same is advantageous for ensuring high bonding strength between the molecules of the first sealing sublayer 131 and the molecules of the second sealing sublayer 132, which is advantageous for increasing the adhesive strength between the first sealing sublayer 131 and the second sealing sublayer 132 after lamination. Alternatively, the material of the first sealing sublayer 131, the material of the second sealing sublayer 132, and the material of the third sealing sublayer 133 are all the same. By using the same material for the first sealing sublayer 131, the second sealing sublayer 132, and the third sealing sublayer 133, it is advantageous to ensure that the molecules of the first sealing sublayer 131 and the molecules of the second sealing sublayer 132 have high bonding strength, and to ensure that the molecules of the second sealing sublayer 132 and the molecules of the third sealing sublayer 133 have high bonding strength, which is in turn advantageous to increasing the adhesive strength between the first sealing sublayer 131 and the second sealing sublayer 132 after lamination, and to increasing the adhesive strength between the second sealing sublayer 132 and the third sealing sublayer 133 after lamination.

[0082] 1A , the first encapsulating sub-layer 131 and the second encapsulating sub-layer 132 are integrally formed. Compared with stacking the separate first encapsulating sub-layer 131 and the second encapsulating sub-layer 132, the integrally formed first encapsulating sub-layer 131 and the second encapsulating sub-layer 132 directly form the encapsulating layer 130, which is advantageous in ensuring high adhesive strength between the first encapsulating sub-layer 131 and the second encapsulating sub-layer 132, and thus in improving the structural stability of the photovoltaic module.

[0083] 1B , the first encapsulating sublayer 131, the second encapsulating sublayer 132, and the third encapsulating sublayer 133 are integrally formed. Compared with stacking the separate first encapsulating sublayer 131, the second encapsulating sublayer 132, and the third encapsulating sublayer 133, the integrally formed first encapsulating sublayer 131, the second encapsulating sublayer 132, and the third encapsulating sublayer 133 directly form the encapsulation layer 130. This is advantageous in ensuring high adhesive strength between the first encapsulating sublayer 131 and the second encapsulating sublayer 132, and between the second encapsulating sublayer 132 and the third encapsulating sublayer 133, and is therefore advantageous in improving the structural stability of the photovoltaic module.

[0084] 1A , the first sealing sublayer 131 and the second sealing sublayer 132 are made of the same material, and the first sealing sublayer 131 and the second sealing sublayer 132 are integrally molded. In some embodiments, a method for forming the sealing layer 130 includes obtaining an initial sealing layer, the initial sealing layer being a non-pre-crosslinked adhesive film, and including a laminated first portion and a second portion. The initial sealing layer is pre-crosslinked from the side of the first portion away from the second portion to cause a crosslinking reaction in some molecules in the initial sealing layer of the first portion, thereby forming the pre-crosslinked, low-fluidity first sealing sublayer 131. The second portion of the initial sealing layer is still a non-pre-crosslinked adhesive film, and the initial sealing layer of the second portion is made into the high-fluidity second sealing sublayer 132. This advantageously reduces the difficulty of obtaining the sealing layer 130. The pre-crosslinking treatment may be a crosslinking treatment such as electron beam irradiation or ultraviolet irradiation.

[0085] In some embodiments, as shown in FIG. 1B, the materials of the first sealing sublayer 131, the second sealing sublayer 132, and the third sealing sublayer 133 are all the same, and the first sealing sublayer 131, the second sealing sublayer 132, and the third sealing sublayer 133 are an integrally molded structure. In some embodiments, a method for forming the sealing layer 130 includes obtaining an initial sealing layer, which may be a non-pre-crosslinked adhesive film, and which includes a first portion, a second portion, and a third portion stacked together. The initial sealing layer is pre-crosslinked from the side of the first portion away from the third portion, so as to crosslink some molecules in the initial sealing layer of the first portion and to crosslink some molecules in the initial sealing layer of the second portion, thereby increasing the proportion of molecules crosslinked in the initial sealing layer of the first portion compared to the proportion of molecules crosslinked in the initial sealing layer of the second portion, thereby forming a pre-crosslinked first sealing sublayer 131 and a pre-crosslinked second sealing sublayer 132 with sequentially increasing fluidity. The initial sealing layer of the third portion is still a non-pre-crosslinked adhesive film, and the initial sealing layer of the third portion is the third sealing sublayer 133 with the highest fluidity, which is advantageous for reducing the difficulty of obtaining the sealing layer 130. Here, the pre-crosslinking treatment may be a crosslinking treatment such as electron beam irradiation or ultraviolet irradiation.

[0086] 1A , a method for forming the sealing layer 130 includes obtaining separate initial first and second sealing sublayers, each of which is a non-pre-crosslinked adhesive film, and pre-crosslinking the initial first sealing sublayer to crosslink some of the molecules within the initial first sealing sublayer, thereby forming a pre-crosslinked first sealing sublayer 131 with low fluidity, and forming the initial second sealing sublayer into a non-pre-crosslinked second sealing sublayer 132 with high fluidity, and then fixing the separate first and second sealing sublayers 131 and 132 together to form the sealing layer 130. Here, the pre-crosslinking may be a crosslinking treatment such as electron beam irradiation or ultraviolet irradiation.

[0087] In some embodiments, as shown in FIG. 1B , a method for forming the sealing layer 130 includes obtaining separate initial first, second, and third sealing sublayers, each of which is a non-pre-crosslinked adhesive film, and performing different degrees of pre-crosslinking treatment on the initial first and second sealing sublayers, such that a portion of the molecules in the first sealing sublayer undergoes a crosslinking reaction and a portion of the molecules in the second sealing sublayer undergo a crosslinking reaction, so that the proportion of molecules crosslinked in the first portion of the initial sealing layer is higher than the proportion of molecules crosslinked in the second portion of the initial sealing layer, thereby forming the pre-crosslinked first sealing sublayer 131 and the pre-crosslinked second sealing sublayer 132 with sequentially increasing fluidity, and the initial third sealing sublayer becomes the non-pre-crosslinked third sealing sublayer 133 with high fluidity, and then fixing the separate first, second, and third sealing sublayers 131, 132, and 133 together to form the sealing layer 130. Here, the preliminary cross-linking treatment may be a cross-linking treatment such as electron beam irradiation or ultraviolet irradiation.

[0088] 1A , the ratio of the ML value of the first sealing sublayer 131 to the ML value of the second sealing sublayer 132 is 1.5 to 8.5. If the ML value of the first sealing sublayer 131 is ML1 and the ML value of the second sealing sublayer 132 is ML2, the ratio of ML1 to ML2 is 1.5 to 8.5, such as 1.5, 2, 4, 7, or 8.5. If the ratio of ML1 to ML2 is too small, the first sealing sublayer 131 becomes highly fluid, which can cause the scorched first sealing sublayer 131 to flow between the unalloyed grid lines 110 and the connecting members 120, resulting in poor contact between the grid lines 110 and the connecting members 120. If the ratio of ML1 to ML2 is too large, the fluidity of the first encapsulating sublayer 131 will be too low, i.e., the proportion of molecules that have undergone a cross-linking reaction in the first encapsulating sublayer 131 before lamination will be too large, resulting in poor adhesive fixing ability of the first encapsulating sublayer 131 in the photovoltaic module after lamination, and there is a risk of separation between the battery cells 100 and the first encapsulating sublayer 131 in the photovoltaic module. Therefore, setting the ratio of ML1 to ML2 to 1.5 to 8.5 is advantageous not only for avoiding poor contact between the grid lines 110 and the connecting members 120, but also for ensuring that the first encapsulating sublayer 131 has high adhesive strength.

[0089] 1B , the ratio of the ML value of the first sealing sublayer 131 to the ML value of the second sealing sublayer 132 is between 1.1 and 3. If the ML value of the first sealing sublayer 131 is ML1 and the ML value of the second sealing sublayer 132 is ML2, the ratio of ML1 to ML2 is between 1.1 and 3, such as 1.5, 2, 2.5, 2.6, or 2.7. If the ratio of ML1 to ML2 is too small, the first sealing sublayer 131 becomes highly fluid, which can cause the scorched first sealing sublayer 131 to flow between the unalloyed grid lines 110 and the connecting members 120, resulting in poor contact between the grid lines 110 and the connecting members 120. If the ratio of ML1 to ML2 is too large, the fluidity of the first sealing sublayer 131 will be too low, i.e., the proportion of molecules that have undergone a cross-linking reaction in the first sealing sublayer 131 before lamination will be too large, resulting in poor adhesive fixing ability of the first sealing sublayer 131 in the photovoltaic module after lamination, and there is a risk of separation between the battery cells 100 and the first sealing sublayer 131 in the photovoltaic module. Therefore, setting the ratio of ML1 to ML2 to 1.1 to 3 is advantageous not only for avoiding poor contact between the grid lines 110 and the connecting members 120 but also for ensuring high adhesive strength of the first sealing sublayer 131.

[0090] 1B , the ratio of the ML value of second sealing sublayer 132 to the ML value of third sealing sublayer 133 is between 1.1 and 4. When the ML value of second sealing sublayer 132 is ML2 and the ML value of third sealing sublayer 133 is ML3, the ratio of ML2 to ML3 is between 1.1 and 4, such as 1.5, 2, 2.5, 2.6, or 3.5. If the ratio of ML2 to ML3 is too small, the fluidity of second sealing sublayer 132 will be too close to that of third sealing sublayer 133, and second sealing sublayer 132 will not function as a good bridge between first sealing sublayer 131 and third sealing sublayer 133, resulting in a reduced adhesive strength between first sealing sublayer 131 and second sealing sublayer 132. If the ratio of ML2 to ML3 is too large, the fluidity of second sealing sublayer 132 will be too close to that of first sealing sublayer 131, and second sealing sublayer 132 will not function as a good bridge between first sealing sublayer 131 and third sealing sublayer 133, reducing the adhesive strength between third sealing sublayer 133 and second sealing sublayer 132. Therefore, setting the ratio of ML2 to ML3 to 1.1 to 4 is advantageous for ensuring high adhesive strength between first sealing sublayer 131 and second sealing sublayer 132, and for ensuring high adhesive strength between second sealing sublayer 132 and third sealing sublayer 133.

[0091] In some embodiments, as shown in FIGS. 1A and 1B , the ML value of the first encapsulating sublayer 131 is 0.4 dN·m to 0.85 dN·m, such as 0.42 dN·m, 0.45 dN·m, 0.5 dN·m, 0.75 dN·m, or 0.8 dN·m. If the ML value of the first encapsulating sublayer 131 is too small, the fluidity of the first encapsulating sublayer 131 is too high, resulting in the first encapsulating sublayer 131 in the scorched state flowing between the unalloyed grid lines 110 and the connecting members 120, causing poor contact between the grid lines 110 and the connecting members 120. If the ML value of the first encapsulating sublayer 131 is too large, the fluidity of the first encapsulating sublayer 131 is too low, i.e., the proportion of molecules cross-linked in the first encapsulating sublayer 131 before lamination is too high, resulting in a poor adhesive and fixing ability of the first encapsulating sublayer 131 in the laminated photovoltaic module. Therefore, by setting the fluidity ML value of the first sealing sub-layer 131 to 0.4 dN·m to 0.85 dN·m, the fluidity of the first sealing sub-layer 131 can be ensured within a reasonable range, which is advantageous not only for avoiding poor contact between the grid line 110 and the connecting member 120 but also for ensuring that the first sealing sub-layer 131 has high adhesive strength.

[0092] 1A , the ML value of the second encapsulating sublayer 132 may be between 0.1 dN·m and 0.3 dN·m, such as 0.12 dN·m, 0.15 dN·m, 0.2 dN·m, 0.25 dN·m, or 0.3 dN·m. If the fluidity of the second encapsulating sublayer 132 is too low, the adhesive fixing ability of the second encapsulating sublayer 132 in the laminated photovoltaic module may be too low. Therefore, setting the ML value of the second encapsulating sublayer 132 between 0.1 dN·m and 0.3 dN·m is advantageous in ensuring that the second encapsulating sublayer 132 has high adhesive strength.

[0093] If the ML value of the first sealing sublayer is ML1 and the ML value of the second sealing sublayer is ML2, refer to Table 1 below to see the effects that the ML values ​​of the first sealing sublayer and the second sealing sublayer have on the connection state between the grid lines and the connecting member after lamination.

[0094] Table 1 JPEG0007734788000001.jpg101161

[0095] The data sources for Table 1 above are as follows: The connection points between the connecting members and grid lines in the same region of the battery cells of a plurality of comparative examples are sampled, and the connection points between the connecting members and grid lines in the same region of the battery cells of a plurality of examples are sampled. The total number of samples for each battery cell may be 50, and the number of samples in which the grid lines of the battery cells form a contact connection with the connecting members is counted. This allows the proportion of the number of samples in which the connecting members and grid lines of each comparative example form a contact connection to the total number of samples to be determined, and the proportion of the number of samples in which the connecting members and grid lines of each example form a contact connection to the total number of samples to be determined.

[0096] As shown in Table 1 above, when the ML value (ML2) of the second encapsulation sublayer is constant, the larger the ML value (ML1) of the first encapsulation sublayer, the higher the percentage of samples in which the connecting members and grid lines form a contact connection to the total number of samples. This means that the percentage of poor contact between the connecting members and grid lines is lower (see Comparative Examples 1-2 and Examples 1-3, or Comparative Examples 3-4 and Examples 4-6). When the ML value (ML1) of the first encapsulation sublayer is 0.4 dN·m or greater, the percentage of samples in which the connecting members and grid lines form a contact connection to the total number of samples exceeds 95%, meaning that the photovoltaic module is an acceptable product (see Examples 1-6). When the percentage of samples in which the connecting members and grid lines form a contact connection to the total number of samples is less than 95%, the photovoltaic module is an unacceptable product (see Comparative Examples 1-4). Therefore, setting the ML value of the first encapsulation sublayer to a value greater than 0.4 dN·m is advantageous in improving the yield and efficiency of photovoltaic modules.

[0097] Continuing to refer to Table 1 above, when the ML value (ML1) of the first sealing sub-layer is 0.4 dN·m or more, changes in the ML value (ML2) of the second sealing sub-layer cannot affect the connection state between the grid lines and the connecting members (see Examples 1 and 4, Examples 2 and 5, or Examples 3 and 6). In other words, the first sealing sub-layer, which has relatively poor fluidity, effectively isolates and shields the second sealing sub-layer.

[0098] In some other embodiments, as shown in FIG. 1B , the ML value of the first sealing sublayer is ML1, the ML value of the second sealing sublayer is ML2, and the ML value of the third sealing sublayer is ML3. The influence of the ML values ​​of the first sealing sublayer, the second sealing sublayer, and the third sealing sublayer in Table 2 below on the connection state between the grid lines and the connecting members after lamination can be referred to.

[0099] Table 2 JPEG0007734788000002.jpg128161

[0100] The data sources for Table 2 above are the same as those for Table 1, so there is no need to repeat them here.

[0101] As shown in Table 2, when the ML value (ML2) of the second encapsulation sublayer is constant and the ML value (ML3) of the third encapsulation sublayer is constant, the larger the ML value (ML1) of the first encapsulation sublayer, the higher the percentage of samples in which the connecting members and grid lines formed contact with each other, i.e., the lower the proportion of poor contact between the connecting members and grid lines (see Comparative Example 1, Examples 1, 1, and 4, or Comparative Example 3, Examples 5, 6, and 8). When the ML value (ML1) of the first encapsulation sublayer is 0.4 dN·m or greater, the percentage of samples in which the connecting members and grid lines formed contact with each other is greater than 95%, i.e., the photovoltaic module is an acceptable product (see Examples 1 to 8). When the ML value (ML1) of the first encapsulation sublayer is less than 0.4 dN·m, the percentage of samples in which the connecting members and grid lines formed contact with each other is less than 95%, and the photovoltaic module is an unacceptable product (see Comparative Examples 1 to 3). Therefore, setting the ML value of the first encapsulating sub-layer to be greater than 0.4 dN·m is advantageous for improving the yield and efficiency of the photovoltaic module.

[0102] As shown in Table 2 above, when the ML value (ML1) of the first sealing sublayer is 0.4 dN m or more, changes in the ML value (ML2) of the second sealing sublayer cannot affect the connection between the grid lines and the connecting members (see Examples 2 and 3, or Examples 6 and 7). That is, the first sealing sublayer, which has relatively poor fluidity, effectively isolates and shields the second sealing sublayer. When the ML value (ML1) of the first sealing sublayer is 0.4 dN m or more, changes in the ML value (ML3) of the third sealing sublayer cannot affect the connection between the grid lines and the connecting members (see Examples 1 and 5, or Examples 2 and 6).

[0103] 1B , the ML value of second sealing sublayer 132 may be 0.3 dN·m to 0.4 dN·m, such as 0.32 dN·m, 0.35 dN·m, 0.36 dN·m, 0.38 dN·m, or 0.39 dN·m. If the ML value of second sealing sublayer 132 is too small, the fluidity of second sealing sublayer 132 may be too close to the fluidity of third sealing sublayer 133, and second sealing sublayer 132 may not provide a good bridge between first sealing sublayer 131 and third sealing sublayer 133, thereby reducing the adhesive strength between first sealing sublayer 131 and second sealing sublayer 132. If the ML of second sealing sublayer 132 is too large, the fluidity of second sealing sublayer 132 will be too close to that of first sealing sublayer 131, and second sealing sublayer 132 will not function as a good bridge between first sealing sublayer 131 and third sealing sublayer 133, thereby reducing the adhesive strength between third sealing sublayer 133 and second sealing sublayer 132. Therefore, setting the ML value of second sealing sublayer 132 to 0.3 dN·m to 0.4 dN·m is advantageous for ensuring high adhesive strength between first sealing sublayer 131 and second sealing sublayer 132, and for ensuring high adhesive strength between second sealing sublayer 132 and third sealing sublayer 133.

[0104] In some embodiments, as shown in FIG. 1B , the ML value of the third encapsulation sublayer 133 is 0.1 dN·m to 0.3 dN·m, such as 0.12 dN·m, 0.15 dN·m, 0.2 dN·m, 0.25 dN·m, or 0.3 dN·m. If the flowability of the third encapsulation sublayer is too low, the adhesive fixing ability of the third encapsulation sublayer in the laminated photovoltaic module will be too low. Therefore, setting the ML value of the third encapsulation sublayer to 0.1 dN·m to 0.3 dN·m is advantageous in ensuring high adhesive strength of the third encapsulation sublayer.

[0105] 4A and 4B are diagrams illustrating a local cross-sectional configuration of a photovoltaic module before stacking provided by an embodiment of the present application;

[0106] 4A and 4B , in the direction from the battery cell 100 toward the sealing layer 130, i.e., the Z direction shown in FIGS. 4A and 4B , the ratio of the thickness L2 of the first sealing sublayer 131 to the maximum thickness L1 of the connecting member 120 is 0.4 to 1. For example, it may be 0.4, 0.5, 0.6, 0.7, or 0.9. If the ratio of the thickness L2 of the first sealing sublayer 131 to the maximum thickness L1 of the connecting member 120 is too large, the thickness L2 of the first sealing sublayer 131 will be too large, and a thick first sealing sublayer 131 will affect the light absorption of the battery cell 100. If the ratio of the thickness L2 of the first sealing sublayer 131 to the maximum thickness L1 of the connecting member 120 is too small, the first sealing sublayer 131 will not be able to adequately shield the second sealing sublayer 132 during the scorching stage of the sealing layers during lamination, and the second sealing sublayer 132 may flow between the grid lines 110 and the connecting member 120. Therefore, setting the ratio of the thickness L2 of the first sealing sublayer 131 to the maximum thickness L1 of the connecting member 120 to a value between 0.4 and 1 is advantageous in preventing a first sealing sublayer 131 that is too thick from blocking light, i.e., in maintaining a high light utilization rate of the battery cell 100, while also advantageous in ensuring that the first sealing sublayer 131 effectively shields the second sealing sublayer 132, thereby ensuring good contact between the grid lines 110 and the connecting member 120.

[0107] 4A , in some embodiments, the ratio of the thickness L2 of the first sealing sublayer 131 to the thickness L3 of the second sealing sublayer 132 in the direction from the battery cell 100 to the sealing layer 130 is 0.3 to 1.5, for example, 0.4, 0.5, 0.6, 0.7, or 1.2. When the thickness L2 of the first sealing sublayer 131 is constant, if the ratio of the thickness L2 of the first sealing sublayer 131 to the thickness L3 of the second sealing sublayer 132 is too large, the thickness L3 of the second sealing sublayer 132 becomes too small. Since the second sealing sublayer 132 has high adhesive strength after lamination, a second sealing sublayer 132 with a too small thickness cannot adequately seal and protect the battery cell 100, and may cause separation between the cover plate and the battery cell 100. Furthermore, if the second encapsulation sublayer 132 is too thin, the overall thickness of the encapsulation layer 130 will be too thin, which may allow water vapor to enter the battery cell 100 and cause damage to the battery cell 100. If the thickness L2 of the first encapsulation sublayer 131 is constant, if the ratio between the thickness L2 of the first encapsulation sublayer 131 and the thickness L3 of the second encapsulation sublayer 132 is too small, the thickness L3 of the second encapsulation sublayer 132 will be too large, and a second encapsulation sublayer 132 that is too thick will affect the light absorption of the battery cell 100. Furthermore, a second encapsulation sublayer 132 that is too thick will increase the manufacturing costs of the photovoltaic module. Therefore, by setting the ratio of the thickness L2 of the first sealing sublayer 131 to the thickness L3 of the second sealing sublayer 132 to 0.3 to 1.5, not only can the second sealing sublayer 132 ensure good sealing and protection of the battery cell 100, but it also helps improve the light utilization rate of the battery cell 100 and rationalize the amount of material used to manufacture the second sealing sublayer 132, which is advantageous for reducing the weight of the photovoltaic module and the manufacturing costs of the photovoltaic module.

[0108] In some embodiments, as shown in FIG. 4B , the ratio of the thickness L2 of the first sealing sublayer 131 to the thickness L3 of the second sealing sublayer 132 in the Z direction is between 1 and 4, such as 1, 2, 2.5, or 3. For a given thickness L2 of the first sealing sublayer 131, if the ratio of the thickness L2 of the first sealing sublayer 131 to the thickness L3 of the second sealing sublayer 132 is too large, the thickness L3 of the second sealing sublayer 132 will be too small. A second sealing sublayer 132 that is too thin will not function as a good bridge between the first sealing sublayer 131 and the third sealing sublayer 133. Furthermore, a second sealing sublayer 132 that is too thin will cause the overall thickness of the sealing layer 130 to be too small, which may allow water vapor to enter the battery cell 100 and cause the battery cell 100 to malfunction. When the thickness L2 of the first encapsulating sublayer 131 is constant, if the ratio of the thickness L2 of the first encapsulating sublayer 131 to the thickness L3 of the second encapsulating sublayer 132 is too small, the thickness L3 of the second encapsulating sublayer 132 will be too large. A second encapsulating sublayer 132 that is too thick will affect the light absorption of the battery cell 100. Furthermore, a second encapsulating sublayer 132 that is too thick will increase the manufacturing costs of the photovoltaic module. Therefore, setting the ratio of the thickness L2 of the first encapsulating sublayer 131 to the thickness L3 of the second encapsulating sublayer 132 to a value between 1 and 4 not only ensures that the second encapsulating sublayer 132 effectively seals and protects the battery cell 100, but also helps improve the light utilization rate of the battery cell 100 and streamline the amount of material used to manufacture the second encapsulating sublayer 132, thereby contributing to a lighter photovoltaic module and a lower manufacturing cost.

[0109] 4B , in some embodiments, the ratio of the thickness L3 of the second sealing sublayer 132 to the thickness L4 of the third sealing sublayer 133 in the Z direction is 0.2 to 0.7, for example, 0.3, 0.4, 0.5, 0.6, or 0.7. When the thickness L3 of the second sealing sublayer 132 is constant, if the ratio of the thickness L3 of the second sealing sublayer 132 to the thickness L4 of the third sealing sublayer 133 is too large, the thickness L4 of the third sealing sublayer 133 will be too small. Since the third sealing sublayer 133 has high adhesive strength after lamination, a thickness L4 of the third sealing sublayer 133 that is too small will not adequately seal and protect the battery cell 100, and may cause separation between the cover plate and the battery cell 100. Furthermore, a third encapsulation sublayer 133 that is too thin will cause the overall thickness of the encapsulation layer 130 to be too thin, which may allow water vapor to enter the battery cell 100 and cause damage to the battery cell 100. When the thickness L3 of the second encapsulation sublayer 132 is constant, if the ratio between the thickness L3 of the second encapsulation sublayer 132 and the thickness L4 of the third encapsulation sublayer 133 is too small, the thickness L4 of the third encapsulation sublayer 133 will be too large, and a third encapsulation sublayer 133 that is too thick will affect the light absorption of the battery cell 100. Furthermore, a third encapsulation sublayer 133 that is too thick will increase the manufacturing costs of the photovoltaic module. Therefore, by setting the ratio of the thickness L3 of the second sealing sublayer 132 to the thickness L4 of the third sealing sublayer 133 to 0.2 to 0.7, not only can the third sealing sublayer 133 ensure good sealing and protection of the battery cell 100, but it is also advantageous for improving the light utilization rate of the battery cell 100 and rationalizing the amount of material used to manufacture the third sealing sublayer 133, which is also advantageous for reducing the weight of the photovoltaic module and the manufacturing costs of the photovoltaic module.

[0110] Note that the maximum thickness L1 of the connecting member 120 described in the examples of the present application is the thickness of the connecting member 120 before lamination, the thickness L2 of the first sealing sublayer 131 is the thickness of the first sealing sublayer 131 before lamination, the thickness L3 of the second sealing sublayer 132 is the thickness of the second sealing sublayer 132 before lamination, and the thickness L4 of the third sealing sublayer 133 is the thickness of the third sealing sublayer 133 before lamination.

[0111] In some embodiments, as shown in FIGS. 4A and 4B , the maximum thickness L1 of the connecting member 120 in the Z direction is 200 μm to 260 μm, such as 200 μm, 210 μm, 230 μm, 235 μm, or 250 μm. If the maximum thickness L1 of the connecting member 120 is too large, the amount of material used for the connecting member 120 will be too large, which will increase the cost of the photovoltaic module. If the maximum thickness L1 of the connecting member 120 is too small, the conductive cross-sectional area of ​​the connecting member 120 will be too small, which will increase resistance loss. Therefore, setting the maximum thickness L1 of the connecting member 120 to 200 μm to 260 μm is advantageous in keeping the dimensions of the connecting member 120 within a reasonable range, reducing the cost and resistance loss of the photovoltaic module, and ultimately improving the efficiency of the photovoltaic module.

[0112] 1A-1B and 4A-4B, in some embodiments, the thickness L2 of the first sealing sublayer 131 in the Z direction is 110 μm to 200 μm, such as 120 μm, 130 μm, 150 μm, 165 μm, or 180 μm. A first sealing sublayer 131 that is too thick may affect the light absorption of the battery cell 100. If the thickness L2 of the first sealing sublayer 131 is too small, the first sealing sublayer 131 may not adequately shield the highly fluid second sealing sublayer 132 during the scorching stage of the lamination process, which may result in the second sealing sublayer 132 flowing between the grid lines 110 and the connecting members 120. Therefore, by setting the thickness L2 of the first sealing sub-layer 131 to 110 μm to 200 μm, it is possible to avoid a first sealing sub-layer 131 that is too thick from blocking light, i.e., it is advantageous to ensure a high light utilization rate of the battery cell 100, while at the same time ensuring that the first sealing sub-layer 131 effectively blocks the second sealing sub-layer 132, which is advantageous to ensure good contact between the grid line 110 and the connecting member 120.

[0113] In some embodiments, as shown in FIGS. 1A and 4A , the thickness L3 of the second encapsulation sublayer 132 in the Z direction is 140 μm to 320 μm, e.g., 150 μm, 165 μm, 170 μm, 200 μm, or 250 μm. A second encapsulation sublayer 132 that is too thin may not adequately seal and protect the battery cell 100, potentially resulting in separation between the cover plate and the battery cell 100. A second encapsulation sublayer 132 that is too thin may also result in the overall thickness of the encapsulation layer 130 being too thin, potentially allowing water vapor to enter the battery cell 100 and cause damage to the battery cell 100. A second encapsulation sublayer 132 that is too thick may affect the light absorption of the battery cell 100. A second encapsulation sublayer 132 that is too thick may also increase the manufacturing costs of the photovoltaic module. Therefore, by setting the thickness L3 of the second sealing sub-layer 132 to 140 μm to 320 μm, not only can the second sealing sub-layer 132 ensure good sealing and protection of the battery cell 100, but it is also advantageous for improving the light utilization rate of the battery cell 100 and rationalizing the amount of manufacturing material used for the second sealing sub-layer 132, which is also advantageous for reducing the weight of the photovoltaic module and the manufacturing cost of the photovoltaic module.

[0114] In some embodiments, as shown in FIGS. 1B and 4B , the thickness L3 of the second encapsulation sublayer 132 in the Z direction is 50 μm to 100 μm, for example, 60 μm, 70 μm, 80 μm, or 90 μm. A second encapsulation sublayer 132 that is too thin cannot provide a good bridge between the first encapsulation sublayer 131 and the third encapsulation sublayer 133. A second encapsulation sublayer 132 that is too thin may cause the overall thickness of the encapsulation layer 130 to be too thin, which may allow water vapor to enter the battery cell 100 and cause the battery cell 100 to malfunction. A second encapsulation sublayer 132 that is too thick may affect the light absorption of the battery cell 100. A second encapsulation sublayer 132 that is too thick may also increase the manufacturing cost of the photovoltaic module. Therefore, by setting the thickness L3 of the second sealing sub-layer 132 to 50 μm to 100 μm, not only can the second sealing sub-layer 132 ensure good sealing and protection of the battery cell 100, but it also helps improve the light utilization rate of the battery cell 100 and rationalize the amount of manufacturing material used for the second sealing sub-layer 132, which is advantageous for reducing the weight of the photovoltaic module and the manufacturing cost of the photovoltaic module.

[0115] In some embodiments, as shown in FIGS. 1B and 4B , the thickness L4 of the third encapsulation sublayer 133 in the direction from the battery cell 100 toward the encapsulation layer 130, i.e., the Z direction shown in FIG. 4B , is 140 μm to 260 μm, for example, 150 μm, 165 μm, 170 μm, 200 μm, or 250 μm. A third encapsulation sublayer that is too thin may not adequately seal and protect the battery cell 100, potentially causing separation between the cover plate and the battery cell 100. Furthermore, a third encapsulation sublayer 133 that is too thin may cause the overall thickness of the encapsulation layer 130 to be too thin, potentially allowing water vapor to enter the battery cell 100 and cause damage to the battery cell 100. A third encapsulation sublayer 133 that is too thick may affect the light absorption of the battery cell 100. Furthermore, a third encapsulation sublayer 133 that is too thick may increase the manufacturing costs of the photovoltaic module. Therefore, by setting the thickness L4 of the third sealing sub-layer 133 to 140 μm to 260 μm, not only can the third sealing sub-layer 133 ensure good sealing and protection of the battery cell 100, but it also helps improve the light utilization rate of the battery cell 100 and rationalize the amount of material used to manufacture the third sealing sub-layer 133, which is advantageous for reducing the weight of the photovoltaic module and the manufacturing costs of the photovoltaic module.

[0116] 1A, 1B, and 2, the photovoltaic module further includes adhesive dots 140 located between some of the battery cells 100 and the connecting members 120, and located on the surface of the battery cells 100 other than the grid lines 110. The adhesive dots 140 are used to fix the connecting members 120 before lamination and prevent the connecting members 120 from moving on the surface of the battery cells 100.

[0117] In some embodiments, as shown in FIGS. 1A and 1B , the photovoltaic module further includes a cover plate 150, which is located on a surface of the sealing layer 130 away from the battery cells 100, and the cover plate 150 may be a glass cover plate, a plastic cover plate, or the like, for protecting the cell strings.

[0118] In the photovoltaic module provided by the above embodiment, the encapsulating layer 130 includes a first encapsulating sublayer 131 adjacent to the surface of the battery cell 100 and the connecting member 120, and a second encapsulating sublayer 132 away from the battery cell 100. The first encapsulating sublayer 131 has a lower fluidity than the second encapsulating sublayer 132. The fluidities of the first encapsulating sublayer 131 and the second encapsulating sublayer 132 are both fluidities at the lamination temperature. That is, the photovoltaic module is a photovoltaic module in the process of lamination. At the lamination temperature, the first encapsulating sublayer 131 adjacent to the connecting member 120 and the battery cell 100 is set to a low fluidity state, thereby preventing the first encapsulating sublayer 131 from flowing between the connecting member 120 and the grid line 110, which would cause poor contact between the connecting member 120 and the grid line 110. This is beneficial to improving the efficiency and yield of the photovoltaic module. In addition, the first sealing sub-layer 131 is used to isolate the second sealing sub-layer 132, which has a relatively high fluidity, and the second sealing sub-layer 132, which has a high fluidity, is used to ensure a high degree of cross-linking of the sealing layer 130, which ensures that the sealing layer 130 can effectively protect the battery, increases the adhesive strength between the sealing layer 130 and the cover plate, and is advantageous for extending the life of the photovoltaic module.

[0119] According to some embodiments of the present application, a method for manufacturing a photovoltaic module is further provided in the embodiments of the present application, and this method for manufacturing a photovoltaic module is used to manufacture the photovoltaic module described in the above embodiments. Hereinafter, the method for manufacturing a photovoltaic module provided in the embodiments of the present application will be described with reference to the drawings. Note that for parts that are the same as or correspond to the above embodiments, reference can be made to the detailed description of the above embodiments, and therefore, there is no need to repeat the description here.

[0120] Fig. 5 is a diagram showing a configuration corresponding to a step of providing a battery cell in a method for manufacturing a photovoltaic module provided in an embodiment of the present application, Fig. 6 is a diagram showing a configuration corresponding to a step of forming adhesive dots in a method for manufacturing a photovoltaic module provided in an embodiment of the present application, Fig. 7 is a diagram showing a configuration corresponding to a step of fixing a connecting member using adhesive dots in a method for manufacturing a photovoltaic module provided in an embodiment of the present application, Fig. 8A is a diagram showing a configuration corresponding to a step of providing a sealing layer in a method for manufacturing a photovoltaic module provided in an embodiment of the present application, Fig. 8B is a diagram showing a configuration corresponding to a step of providing a sealing layer in a method for manufacturing a photovoltaic module provided in another embodiment of the present application, Fig. 9A is a diagram showing a configuration corresponding to a photovoltaic module after a stacking process in a method for manufacturing a photovoltaic module provided in an embodiment of the present application, and Fig. 9B is a diagram showing a configuration corresponding to a photovoltaic module after a stacking process in a method for manufacturing a photovoltaic module provided in another embodiment of the present application. Note that Figs. 5 to 9B omit the number of battery cells, and illustrate only one battery cell as an example.

[0121] 5, a method of manufacturing a photovoltaic module includes providing a plurality of battery cells 100 having a plurality of gridlines 110 on a surface thereof. In some embodiments, the gridlines 110 can be formed using a screen printing and sintering process.

[0122] 6 and 7, connection members 120 are installed on the surfaces of the battery cells 100. One end of each connection member is provided on the front surface of one of the adjacent battery cells, and the other end of each connection member is provided on the back surface of the other of the adjacent battery cells.

[0123] In some embodiments, installing the connecting member 120 further includes forming adhesive dots 140. As shown in Fig. 6, uncured adhesive dots 140 can be formed on a portion of the surface of the battery cell 100 other than the grid lines 110. As shown in Fig. 7, the connecting member 120 is laid on the surface of the battery cell 100, and the adhesive dots 140 are positioned between the battery cell 100 and the connecting member 120. After the connecting member 120 is laid, the adhesive dots 140 can be cured by ultraviolet irradiation or other low-temperature treatment methods, and the adhesive dots 140 can be used to fix the connecting member 120 and prevent the connecting member 120 from moving.

[0124] As shown in FIG. 8A, a sealing layer 130 is provided on the surface of the battery cell 100, and the sealing layer 130 is located on the side of the connecting member 120 away from the battery cell 100. The sealing layer 130 includes a first sealing sublayer 131 and a second sealing sublayer 132 arranged sequentially along the direction away from the battery cell 100.

[0125] Alternatively, as shown in FIG. 8B , a sealing layer 130 is installed on the surface of the battery cell 100, and the sealing layer 130 is located on the side of the connecting member 120 away from the battery cell 100, and the sealing layer 130 includes a first sealing sublayer 131, a second sealing sublayer 132, and a third sealing sublayer 133 arranged sequentially along the direction away from the battery cell 100.

[0126] As shown in FIGS. 8A-8B, in some embodiments, a cover plate 150 is installed on the surface of the sealing layer 130 that faces away from the battery cell at the same time as the sealing layer 130 is installed.

[0127] 9A , a lamination process is performed on the battery cell 100, the connection member 120, and the sealing layer 130 at a predetermined temperature so that some of the connection members 120 located above the grid lines 110 contact and connect with adjacent partial grid lines 110, thereby fixing the battery cell 100 and the sealing layer 130. Here, the fluidity of the first sealing sub-layer 131 at the predetermined temperature is lower than the fluidity of the second sealing sub-layer 132 at the predetermined temperature.

[0128] 9B , a lamination process is performed on the battery cells 100, the connection members 120, and the sealing layer 130 at a predetermined temperature so that some of the connection members 120 located above the grid lines 110 contact and connect with some of the adjacent grid lines 110, thereby fixing the battery cells 100 and the sealing layer 130. Here, the fluidity of the third sealing sublayer 133 at the predetermined temperature, the fluidity of the second sealing sublayer 132 at the predetermined temperature, and the fluidity of the first sealing sublayer 131 at the predetermined temperature sequentially decrease.

[0129] In some embodiments, the sealing layer 130 is secured to the cover plate 150 by a lamination process.

[0130] By setting the first sealing sub-layer 131 adjacent to the connecting member 120 and the battery cell 100 to a low fluidity state, the first sealing sub-layer 131 is prevented from flowing between the connecting member 120 and the grid line 110, thereby preventing poor contact between the connecting member 120 and the grid line 110, which is beneficial to improving the efficiency and yield of the photovoltaic module. Furthermore, the first sealing sub-layer 131 is used to isolate the second sealing sub-layer 132, which has a relatively high fluidity, and the second sealing sub-layer 132, which also has a relatively high fluidity, is used to ensure the adhesive strength between the second sealing sub-layer 132 and the cover plate. Furthermore, the sealing layer 130 is used to provide good protection for the battery, which is beneficial to extending the life of the photovoltaic module. Alternatively, the first sealing sublayer 131 can be used to isolate the second and third sealing sublayers 132 and 133, which have relatively high fluidity, and the second sealing sublayer 132 can be used as a bridge between the first and third sealing sublayers 131 and 133, which is advantageous for increasing the adhesive strength between the first and third sealing sublayers 131 and 133. The third sealing sublayer 133, which has the highest fluidity, can be advantageous for ensuring strong adhesive strength between the sealing layer 130 and the cover plate, which is advantageous for extending the service life of the photovoltaic module.

[0131] In addition, the preset temperature may be higher than the temperature at which the connecting members 120 and the grid lines 110 form an alloy and lower than the temperature at which a cross-linking reaction occurs in the sealing layer 130, so that the connecting members 120 and the grid lines 110 form an alloy at the preset temperature and the sealing layer 130 undergoes a cross-linking reaction after the connecting members 120 and the grid lines 110 form an alloy.

[0132] In the photovoltaic module manufacturing method provided in the above embodiment, the first encapsulating sub-layer 131 adjacent to the connecting member 120 and the battery cell 100 is set to a low fluidity state, thereby preventing the first encapsulating sub-layer 131 from flowing between the connecting member 120 and the grid line 110, which could cause poor contact between the connecting member 120 and the grid line 110, and is advantageous for forming a photovoltaic module with high yield and efficiency. In addition, the first encapsulating sub-layer 131 is used to isolate the outer encapsulating layer 132, which has a relatively high fluidity, and the second encapsulating sub-layer 132, which has a high fluidity, is used to ensure a high degree of cross-linking in the encapsulating layer 130, which in turn ensures that the encapsulating layer 130 can effectively protect the battery and increase the adhesive strength between the encapsulating layer 130 and the cover plate, which is advantageous for forming a photovoltaic module with high structural stability.

[0133] It should be noted that in the drawings provided in this embodiment, the structure of the photovoltaic module and the shape of the photovoltaic module do not limit the structure of the photovoltaic module and the shape of the photovoltaic module in this embodiment. It can be understood that the structure of the photovoltaic module and the shape of the photovoltaic module can be designed and modified accordingly as needed.

[0134] Those skilled in the art will understand that the above embodiments are specific examples of realizing the present application, but that various changes in form and details are possible in practice without departing from the spirit and scope of the present application. Since anyone skilled in the art can make changes and modifications without departing from the spirit and scope of the present application, the scope of protection of the present application should be based on the scope limited by the claims.

Claims

1. 1. A method of manufacturing a photovoltaic module, comprising: providing a plurality of battery cells, each of the battery cells having opposing front and back surfaces, each of the battery cells having a plurality of grid lines on both the front and back surfaces; providing a plurality of connection members by placing a first end of each connection member on a front surface of a first battery cell among the adjacent battery cells and a second end of each connection member on a back surface of a second battery cell among the adjacent battery cells, wherein the first end is in contact with and connected to the plurality of grid lines on the front surface of the first battery cell and the second end is in contact with and connected to the plurality of grid lines on the back surface of the second battery cell; providing a sealing layer by positioning a first sealing sublayer of each sealing layer closer to a plurality of connection members and portions of the battery cells not covered by the connection members than a second sealing sublayer, and positioning the second sealing sublayer on a surface of the first sealing sublayer away from the battery cells, wherein the first sealing sublayer has a lower fluidity than the second sealing sublayer, the ratio of the ML value of the first sealing sublayer to the ML value of the second sealing sublayer is 1.5 to 8.5, the ML value of the first sealing sublayer is 0.4 dN m to 0.85 dN m, and the ML value of the second sealing sublayer is 0.1 dN m to 0.3 dN m, and the sealing layer is composed of only the first sealing sublayer and the second sealing sublayer; providing a cover plate on a surface of the second sealing sub-layer facing away from the battery cell; laminating the battery cell, the connection member, and the sealing layer at a predetermined temperature so as to fix the battery cell and the sealing layer together; 10. A method for manufacturing a photovoltaic module, comprising:

2. the method further includes forming a plurality of adhesive dots located between some of the battery cells and the connection member and on a surface of the battery cells other than the grid lines.

2. The method for manufacturing a photovoltaic module according to claim 1.

3. the first sealing sub-layer and the second sealing sub-layer are integrally formed structures; 2. The method for manufacturing a photovoltaic module according to claim 1.

4. a ratio of a thickness of the first sealing sub-layer to a maximum thickness of the connection member in a direction from the battery cell toward the corresponding sealing layer is 0.4 to 1; 2. The method for manufacturing a photovoltaic module according to claim 1.

5. a ratio of a thickness of the first sealing sub-layer to a thickness of the second sealing sub-layer in a direction from the battery cell toward the corresponding sealing layer is 0.3 to 1.5; 2. The method for manufacturing a photovoltaic module according to claim 1.

6. the material of the first sealing sub-layer and the material of the second sealing sub-layer are the same; 2. The method for manufacturing a photovoltaic module according to claim 1.

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