Photovoltaic panels

Abstract

The embodiment of the present application relates to a photovoltaic module, comprising: a plurality of cells, each of which comprises a plurality of grid lines arranged at intervals along a first direction; a plurality of connecting components, each of which is in electrical contact with at least one of the grid lines of any two adjacent cells, and the melting point of the connecting component is a first temperature; a plurality of glue point groups, each of which is located on the surface of a corresponding cell, the glue point group comprises a plurality of glue points, and the plurality of glue points are in contact with and connected to a connecting component corresponding to the glue point group; a packaging film, the packaging film covers the surfaces of the plurality of cells and the surfaces of the plurality of connecting components, the melting point of the portion of the packaging film adjacent to the plurality of cells is a second temperature, and the second temperature is greater than the first temperature; a cover plate, the cover plate covers the surface of the packaging film away from the plurality of cells. At least it is helpful to improve the reliability of the photovoltaic module.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of solar cells, and in particular to a photovoltaic module. Background Art

[0002] Fossil energy causes air pollution and has limited reserves, while solar energy has the advantages of being clean, pollution-free and abundant in resources. Therefore, solar energy is gradually becoming the core clean energy to replace fossil energy. Since solar cells have good photoelectric conversion efficiency, they have become the focus of development of clean energy utilization.

[0003] For conventional solar cells, sunlight enters the cell from the cell surface, and the metal electrode on the cell surface will block part of the light that hits the cell surface, so the light energy of the light hitting the metal electrode cannot be converted into electrical energy. In order to reduce the blocking of light by the grid line, during the preparation of photovoltaic modules, the main grid can be replaced by a welding ribbon, which is directly connected to the cell grid to collect current and realize cell interconnection. Summary of the invention

[0004] The embodiments of the present application provide a photovoltaic module, which is at least beneficial to improving the reliability of the photovoltaic module and the connection effect between solar cells.

[0005] An embodiment of the present application provides a photovoltaic module, comprising: a plurality of battery cells, each of the plurality of battery cells comprising a plurality of grid lines arranged at intervals along a first direction; a plurality of connecting components, each of the plurality of connecting components electrically contacts at least one of the plurality of grid lines of any two adjacent battery cells, and the melting point of the connecting component is a first temperature; a plurality of glue point groups, each of the plurality of glue point groups is located on a surface of a corresponding battery cell, the glue point group comprises a plurality of glue points, and the plurality of glue points are in contact and connected with a corresponding connecting component of the glue point group; a packaging film, the packaging film covers the surfaces of the plurality of battery cells and the surfaces of the plurality of connecting components, the melting point of a portion of the packaging film adjacent to the plurality of battery cells is a second temperature, and the second temperature is greater than the first temperature; a cover plate, the cover plate covers the surface of the packaging film away from the plurality of battery cells.

[0006] In some embodiments, the temperature difference between the first temperature and the second temperature is 20°C to 40°C.

[0007] In some embodiments, the first temperature is 130°C to 145°C.

[0008] In some embodiments, the second temperature is 150°C to 185°C.

[0009] In some embodiments, the packaging film includes a POE film, an EVA film, a PVB film, an EPE film or an EP film.

[0010] In some embodiments, the connecting component extends along the second direction, and in a direction perpendicular to the second direction, a width of the connecting component is 0.2 mm to 0.4 mm.

[0011] In some embodiments, the packaging film includes a first adhesive film layer and a second adhesive film layer, the first adhesive film layer covers the surface of the multiple connecting components and the surface of the multiple battery cells, the second adhesive film layer covers the surface of the first adhesive film layer away from the multiple battery cells, and the melting point of the first adhesive film layer is the second temperature.

[0012] In some embodiments, the melting point of the second adhesive film layer is less than or equal to the melting point of the first adhesive film layer.

[0013] In some embodiments, the number of glue dots included in each of the glue dot groups is 3 to 15.

[0014] In some embodiments, the connecting component includes an inner core and a wrapping layer, the wrapping layer covers the inner core, and the melting point of the wrapping layer is the first temperature.

[0015] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0016] In the photovoltaic module provided by the embodiment of the present application, during the process of connecting adjacent battery cells in series, a connecting component with a melting point of a first temperature is used to electrically contact the grid lines on two adjacent battery cells respectively, so as to realize the series connection of adjacent battery cells, and a packaging film with a melting point of a second temperature close to the battery cell is selected to prepare the photovoltaic module, and the second temperature is greater than the first temperature, thereby ensuring that the melting time of the adhesive film close to the battery cell during the lamination process of the component to be laminated will be later than the melting time of the connecting component, so that the connecting component can melt earlier than the adhesive film and fully electrically contact the grid line, thereby greatly avoiding the problem of insulation between the connecting component and the grid line caused by the adhesive film flowing between the connecting component and the grid line after melting, thereby improving the electrical connection reliability and connection effect between the grid line and the connecting component; the connecting component is fixed above the grid line in advance by a glue point group, thereby avoiding the displacement of the connecting component during the lamination process, thereby improving the accuracy and safety of the electrical contact between the connecting component and the grid line during the series connection of the battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0018] Figure 1A schematic diagram of the overall structure of a photovoltaic module provided in one embodiment of the present application;

[0019] Figure 2 A schematic diagram of the structure of a battery string provided in one embodiment of the present application;

[0020] Figure 3 A schematic diagram of a partial cross-sectional structure of a photovoltaic module provided in one embodiment of the present application;

[0021] Figure 4 A schematic diagram of the structure of another photovoltaic module provided in one embodiment of the present application;

[0022] Figure 5 A schematic diagram of the structure of another photovoltaic module provided in one embodiment of the present application;

[0023] Figure 6 A schematic diagram of a partial cross-sectional structure of another photovoltaic module provided in one embodiment of the present application. DETAILED DESCRIPTION

[0024] The reliability of busbar-free photovoltaic modules currently prepared using busbar-free solar cells is relatively poor.

[0025] An embodiment of the present application provides a photovoltaic module. During the production process of the photovoltaic module, when adjacent battery cells are connected in series, a connecting component with a melting point of a first temperature is used to electrically contact the grid lines on two adjacent battery cells respectively, so as to realize the series connection of the adjacent battery cells, and a packaging film with a melting point of a second temperature close to the battery cell is selected to prepare the photovoltaic module, and the second temperature is greater than the first temperature, thereby ensuring that the melting time of the adhesive film close to the battery cell during the lamination process of the component to be laminated will be later than the melting time of the connecting component, so that the connecting component can melt earlier than the adhesive film and fully electrically contact the grid line, thereby greatly avoiding the insulation problem between the connecting component and the grid line caused by the adhesive film flowing between the connecting component and the grid line after melting, thereby improving the electrical connection reliability and connection effect between the grid line and the connecting component; the connecting component is fixed above the grid line in advance by a glue point group, thereby avoiding the displacement of the connecting component during the lamination process, thereby improving the accuracy and safety of the electrical contact between the connecting component and the grid line during the series connection of the battery cells.

[0026] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0027] An embodiment of the present application provides a photovoltaic assembly, referring to Figures 1 to 3 ,in, Figure 1 This is a schematic diagram of the structure of the photovoltaic module after packaging. Figure 2 This is a top view of the battery string in the photovoltaic module along the cover stacking direction. Figure 3 Schematic diagram of the cross-sectional structure of a local area a in a photovoltaic module, wherein the X direction is perpendicular to the first direction.

[0028] The photovoltaic module comprises: a plurality of cells 100, each of the plurality of cells 100 comprising a plurality of grid lines 101 arranged at intervals along a first direction; a plurality of connecting components 110, each of the plurality of connecting components 110 being in electrical contact with at least one grid line 101 of the plurality of grid lines 101 of any two adjacent cells 100, and the melting point of the connecting component 110 being a first temperature; a plurality of glue point groups 120, each of the plurality of glue point groups 120 being located at a corresponding A surface of a battery cell 100, a glue point group 120 includes a plurality of glue points 121, and the plurality of glue points 121 are in contact and connected with a corresponding connecting component 110 of the glue point group 120; a packaging film 130, the packaging film 130 covers the surfaces of the plurality of battery cells 100 and the surfaces of the plurality of connecting components 110, and the melting point of a portion of the packaging film 130 adjacent to the plurality of battery cells 100 is a second temperature, and the second temperature is greater than the first temperature; a cover plate 140, the cover plate 140 covers the surface of the packaging film 130 away from the plurality of battery cells.

[0029] In the process of preparing the photovoltaic module, the connecting component 110 is used to electrically contact at least one grid line 101 of each of the two adjacent battery cells 100, and the connecting component 110 is used to replace the main grid while realizing the series connection of the adjacent battery cells 100, thereby reducing the light energy absorption loss of the battery cells 100 due to the shielding of the grid lines, and improving the photoelectric conversion efficiency of the photovoltaic module; the melting point of the connecting component 110 in the photovoltaic module is a first temperature, and the melting point of the portion of the packaging film 130 adjacent to the multiple battery cells 100 for preparing the photovoltaic module is a second temperature, and the second temperature is greater than the first temperature. By selecting the connecting component 110 with a melting point lower than the melting point of the portion of the packaging film 130 adjacent to the multiple battery cells 100 to prepare the photovoltaic module, so that during the lamination process of the photovoltaic module, The melting of the connecting component 110 is earlier than the melting of the adhesive film of the adjacent multiple battery cells 100, and the connecting component 110 can fully make electrical contact with the grid line 101, which reduces the risk of the adhesive film of the adjacent multiple battery cells 100 melting and flowing between the connecting component 110 and the grid line 101, resulting in insulation between the connecting component 110 and the grid line 101, thereby improving the interconnection effect of adjacent battery cells 100 and the reliability of the photovoltaic module; in the process of connecting the adjacent battery cells 100 in series using the connecting component 110, by setting the glue point group 120 and using the multiple glue points 121 in the glue point group 120 to fix the connecting component 110, the displacement of the connecting component 110 during the lamination process is avoided, and the accuracy and safety of the electrical contact between the connecting component 110 and the grid line 101 during the series connection of the battery cells 100 are improved.

[0030] Among them, the portion of the packaging film 130 adjacent to multiple battery cells 100 refers to the portion of the packaging film 130 that is in contact with the battery cells 100 and the portion of the packaging film 130 that is spaced apart from the battery cells 100 by a distance less than a certain value, for example, 0.1 mm, 0.5 mm, 1 mm or 2 mm.

[0031] In some embodiments, the cell 100 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell. The multi-compound solar cell can specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell or a perovskite solar cell.

[0032] It should be understood that the battery cell 100 is a whole battery or a sliced ​​battery. A sliced ​​battery refers to a battery cell formed by a complete whole battery through a cutting process. The cutting process includes: laser grooving + cutting process and thermal stress battery separation process.

[0033] In some embodiments, the sliced ​​cell is a half-cell cell, and the half-cell cell can also be understood as a half-cell cell or a two-slice cell. The function of the half-cell assembly is to increase the power generation by reducing the resistance loss. According to Ohm's law, the interconnection power loss of solar cells is proportional to the square of the current. After the battery is cut in half, the current size is also reduced by half, and the power loss is also reduced to one-fourth of the full-size battery loss. The increase in the number of cells will also increase the number of cell gaps accordingly. Through the reflection of the component backplane, the cell gap helps to increase the short-circuit current. In addition, the half-cell assembly can optimize the width of the battery ribbon. Conventionally, it is necessary to increase the width of the ribbon to reduce the power loss and reduce the width of the ribbon to reduce the shading loss. An optimized balance is made. The half-cell assembly reduces the battery loss, and the width of the ribbon can be set thinner to reduce the shading loss, which is beneficial to improve the battery efficiency and power consumption. In addition, the sliced ​​battery can also be a three-slice battery, a 4-slice battery, or an 8-slice battery.

[0034] In some embodiments, the temperature difference between the first temperature and the second temperature is 20°C to 40°C.

[0035] In the process of preparing the photovoltaic module, the encapsulation film 130 is formed by laminating the adhesive film arranged on the entire surface and the back side of the battery string composed of multiple battery cells 100, that is, the adhesive film is laid on the entire surface and the back side of the battery string, and the encapsulation film 130 covering the battery string is formed after lamination. Similarly, in the process of preparing the photovoltaic module, the connecting component 110 is first fixed to the preset position on the surface of the battery cell 100 by the multiple glue points 121 in the corresponding glue point group 120, and then in the process of lamination of the photovoltaic module, the connecting component 110 is melted and forms an electrical contact with at least one grid line 101 on the surface of each battery cell 100 in two adjacent battery cells 100, so as to realize the series connection of adjacent battery cells 100.

[0036] In the process of preparing photovoltaic modules, the lamination process is used to enable the connection component 110 to connect two adjacent cells 100 in series, and at the same time, the adhesive film can form a packaging film 130 that covers the battery string composed of multiple cells 100 after melting. Therefore, when the melting point of the portion of the packaging film 130 adjacent to the multiple cells 100 is too small to differ from the melting point of the connection component 110, that is, when the difference between the second temperature and the first temperature is too small, the melting time of the portion of the packaging film 130 adjacent to the multiple cells 100 during the lamination process is very short to the melting time of the connection component 110, and the probability of the melted adhesive film flowing between the connection component 110 and the grid line 101 is too high, which easily leads to the connection component 110 and the grid line 101 being isolated and insulated by the adhesive film. When the difference between the second temperature and the first temperature is too large, the melting time of the portion of the packaging film 130 adjacent to the multiple battery cells 100 during the lamination process is too large compared to the melting time interval of the connecting component 110. The adhesive film melts long after the connecting component 110 melts, and the required heating time is greatly increased. At the same time, after the connecting component 110 melts, it may flow on the surface of the battery cell 100, causing the grid lines 101 of different polarities to be directly connected, causing a short circuit, thereby reducing the safety of the series connection of the battery cells 100 and the photovoltaic module.

[0037] The yield of battery strings with different differences between the melting points of the connecting component 110 and the adhesive film forming the portion of the packaging film 130 adjacent to the multiple battery cells 100 and the melting point of the connecting component 110 can be referred to Table 1, wherein the battery string yield refers to the yield of electrical contact between the connecting component 110 and the grid lines 101 on the battery cells 100 during the preparation of the battery string using the connecting component 110.

[0038] Test items Melting point of connecting parts Film melting point Battery string yield Example 1 125 150 99.8％ Example 2 135 165 99.7％ Example 3 145 180 99.8％ Comparative Example 1 125 135 99.1％ Comparative Example 2 125 125 98.9％ Comparative Example 3 135 125 97.0％ Comparative Example 4 135 145 99.2％ Comparative Example 5 135 135 98.6％ Comparative Example 6 145 135 97.2％ Comparative Example 7 145 155 99.1％ Comparative Example 8 145 145 98.8％ Comparative Example 9 155 145 97.4％

[0039] Table 1

[0040] Therefore, in the process of preparing photovoltaic modules, the difference between the melting point of the adhesive film forming the portion of the packaging film 130 adjacent to the multiple battery cells and the melting point of the connecting component 110, that is, the difference between the second temperature and the first temperature, can be controlled within a range of 20°C to 40°C. For example, the difference between the second temperature and the first temperature can be controlled within a range of 21°C, 22.5°C, 23.75°C, 25°C, 28°C, 31°C, 34.5°C, 37°C or 39.5°C, etc. By controlling the difference between the second temperature and the first temperature within a suitable range, it is ensured that the time interval between the melting time of the connecting component 110 and the melting time of the adhesive film forming the portion of the packaging film 130 adjacent to the plurality of battery cells is large enough, thereby improving the electrical contact effect between the connecting component 110 and the grid line 101, preventing the melted adhesive film from flowing between the connecting component 110 and the grid line 101 to cause poor electrical contact or even insulation, and also ensuring the accuracy of the electrical contact between the connecting component 110 and the grid line 101, reducing the possibility of short circuits of grid lines 101 of different polarities under the action of the flowing connecting component 110, and improving the safety of the series connection of battery cells 100 and photovoltaic modules.

[0041] In some embodiments, the first temperature is 120°C to 160°C.

[0042] In the process of preparing photovoltaic modules, the specific value of the melting point of the connecting component 110, i.e., the first temperature, will affect the heating time and the duration of the entire process during the lamination process of the photovoltaic module. At the same time, the melting point of the connecting component 110 will also affect the reliability and application scenarios of the photovoltaic module during use. In the case where the melting point of the connecting component 110 is too low, during the application of the photovoltaic module after lamination, if the photovoltaic module is partially shielded, the connecting component 110 may melt due to the high temperature generated by the battery cell, thereby causing the connecting component 110 to fall off or flow to the grid line 101 with different polarities, causing further short circuits, affecting the safety and reliability of the photovoltaic module. In the case where the melting point of the connecting component 110 is too high, the heating time and heating temperature required in the lamination process are both high, which easily leads to the loss of photoelectric conversion performance of the battery cell 100 due to excessively long high-temperature heating time during the lamination process, thereby affecting the photoelectric conversion capacity of the entire photovoltaic module, and also affecting the preparation cost of the photovoltaic module.

[0043] Therefore, in the process of preparing photovoltaic modules, the melting point of the selected connecting component 110, i.e., the first temperature, can be controlled within the range of 120°C to 160°C. For example, a connecting component 110 with a melting point of 122°C, 125°C, 130°C, 133°C, 135°C, 137.5°C, 140°C, 142.5°C, 145°C, 150°C, 155°C or 157.5°C can be selected to prepare photovoltaic modules. By controlling the melting point, i.e., the first temperature, of the connecting component 110 within a suitable range, the reliability and safety of the connecting component 110 during the operation of the photovoltaic module can be improved, the probability of the connecting component 110 falling off can be reduced, the damage to the photoelectric conversion capacity of the solar cell during the lamination process and the preparation cost of the photovoltaic module can be reduced, and the photoelectric conversion capacity and application scenarios of the photovoltaic module can be improved.

[0044] It should be understood that the photovoltaic module includes multiple connecting components 110, and the melting points of each connecting component 110 can be the same or different, as long as the melting point of each connecting component 110 is within the range of 120°C to 160°C. The embodiment of the present application does not limit the specific size of the melting point of the connecting component 110.

[0045] In some embodiments, the second temperature is 140°C to 200°C.

[0046] During the preparation of photovoltaic modules, the melting point of the portion of the packaging film 130 adjacent to the multiple cells 100, that is, the specific size of the second temperature, will affect the heating temperature and duration during the lamination process of the photovoltaic module, and will also affect the time interval between the melting time of the adhesive film forming the portion of the packaging film 130 adjacent to the multiple cells 100 and the melting time of the connecting component 110. In the case where the second temperature is too low, the time interval between the melting time of the adhesive film forming the portion of the packaging film 130 adjacent to the multiple cells 100 and the melting time of the connecting component 110 is very small, and the probability of the melted adhesive film flowing between the connecting component 110 and the grid line 101 is relatively high, and the reliability of the series connection of the cells 100 cannot be guaranteed. In the case where the second temperature is too high, the heating temperature required in the lamination process is relatively high, and the heating time is also relatively long, which is likely to cause a large loss of photoelectric conversion performance of the cell 100, thereby causing a decrease in the photoelectric conversion capacity of the photovoltaic module.

[0047] Therefore, in the process of preparing the photovoltaic module, the melting point of the portion of the packaging film 130 adjacent to the plurality of cells 100, i.e., the second temperature, can be set within the range of 140°C to 200°C, for example, the second temperature can be set to 142.5°C, 145°C, 147.5°C, 150°C, 155°C, 160°C, 165.5°C, 175°C, 180°C, 185°C, 195°C or 198°C, etc. By setting the melting point of the portion of the packaging film 130 adjacent to the plurality of cells 100 within a suitable range, the reliability of the photovoltaic module is improved, the photoelectric conversion performance loss of the cells in the photovoltaic module is reduced, and the photoelectric conversion efficiency of the photovoltaic module is improved.

[0048] In some embodiments, the packaging film 130 includes a POE film, an EVA film, a PVB film, an EPE film, or an EP film.

[0049] Polyethylene vinylacetate (EVA) film has the advantages of low cost, convenient processing, fast cross-linking speed and good bonding effect. Polyolefin elastomer (POE) film has the advantages of good material performance, high resistivity, large water vapor barrier rate and not easy to change color. Polyvinyl butyral film (PVB) film has the advantages of high safety, reusability, high stability and not easy to change color. EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, which takes into account the bonding effect of the battery cell 100 and the cover plate 140, and has good resistivity and water vapor barrier rate. EP film refers to a co-extruded film formed by stacking EVA film + POE film in sequence, which improves the bonding effect of the film to a certain extent and effectively improves the resistivity and water vapor barrier rate of the film.

[0050] The role of the packaging film 130 is to protect the battery cells while allowing sunlight to reach the battery cells through the film to the maximum extent, thereby improving the power generation efficiency of the photovoltaic module. Therefore, in the process of preparing photovoltaic modules, different packaging films 130 can be selected in combination with the specific application scenarios of the photovoltaic modules. For example, in the scenario of reducing the cost of preparing photovoltaic modules, EVA film can be selected to form the packaging film 130 through lamination; in the case of taking into account the safety and cost of photovoltaic modules to a certain extent, POE film can be selected to form the packaging film 130 through lamination; in the case of improving the reliability and safety of photovoltaic modules as much as possible, EPE film can be selected to form the packaging film 130 through lamination, etc. By selecting films of different materials to form the packaging film 130 according to specific application scenarios, the application prospects of photovoltaic modules can be improved.

[0051] In addition, during the preparation of the packaging film 130, a mixture of films of different materials may be used. For example, different types of films such as EVA film + POE film, POE film + PVB film, EVA film + PVB film, EPE film + POE film or ER film + PVB film may be arranged on opposite sides of the plurality of battery cells 100, and then the packaging film 130 may be formed by lamination. In other words, the packaging film 130 may include a combination of one or more of POE film, EVA film, PVB film, EPE film and EP film, and the embodiment of the present application does not limit the type of film selected during the preparation of the packaging film 130 and the specific placement of the film.

[0052] refer to Figures 1 to 5 ,in, Figure 4 is a schematic diagram of the structure of a photovoltaic module in which the encapsulation film 130 is composed of a single layer of adhesive film, Figure 5 Schematic diagram of the structure of a photovoltaic module in which the packaging film 130 is composed of multiple layers of adhesive film. In some embodiments, the packaging film 130 includes a first adhesive film layer 131 and a second adhesive film layer 132, the first adhesive film layer 131 covers the surfaces of multiple connecting components 110 and the surfaces of multiple battery cells 100, the second adhesive film layer 132 covers the surface of the first adhesive film layer 131 away from the multiple battery cells 100, and the melting point of the first adhesive film layer 131 is the second temperature.

[0053] During the preparation of the packaging film 130, a layer of adhesive film having a melting point greater than that of the connecting component 110 may be laid on opposite sides of the plurality of battery cells 100, and then the two layers of adhesive film may be combined by lamination to form the packaging film 130. In order to ensure that the melting point of the portion of the packaging film 130 adjacent to the plurality of battery cells 100 is greater than that of the connecting component 110, the types of adhesive films that can be selected are relatively limited, and cannot meet some application scenarios with specific requirements for the functions of the packaging film 130.

[0054] Therefore, in the process of preparing the packaging film 130, at least two layers of adhesive films stacked in sequence can be laid on opposite sides of the plurality of battery cells 100 in a direction perpendicular to the surface of the battery cells 100 according to the functional requirements of the packaging film 130 in the application scenario, wherein the melting point of the adhesive film covering the surface of the plurality of battery cells 100 and the surface of the plurality of connecting components 110 is greater than the melting point of the connecting components 110, and other adhesive films can be selected according to the functional requirements of the packaging film 130 such as insulation, water vapor barrier rate, safety or the degree of color change. Then, through lamination, a packaging film 130 is formed, which is composed of a first adhesive film layer 131 covering the surface of the plurality of connecting components 110 and the surface of the plurality of battery cells 100, and a second adhesive film layer 132 covering the surface of the first adhesive film layer 131 away from the plurality of battery cells 100, wherein the melting point of the first adhesive film layer 131 is the second temperature.

[0055] In the process of forming the packaging film 130, a plurality of adhesive film layers stacked in a direction perpendicular to the surface of the battery cells 100 are laid on opposite sides of the plurality of battery cells 100, so that the packaging film 130 is composed of a first adhesive film layer 131 covering the plurality of battery cells 100 and the plurality of connecting components 110 and having a melting point greater than the melting point of the connecting components 110, and a second adhesive film layer 132 covering the first adhesive film layer 131 away from the surface of the plurality of battery cells 100, so that the melting time of the adhesive film of the first adhesive film layer 131 constituting the packaging film 130 during the lamination process is ensured to be later than the melting time of the connecting components 110, thereby reducing the probability of the melted adhesive film flowing between the connecting components 110 and the grid lines 101, and improving the reliability of the connection between adjacent battery cells 100; at the same time, the second adhesive film layer 132 is formed on the surface of the first adhesive film layer 131 away from the plurality of battery cells 100, so that the packaging film 130 can use the second adhesive film layer 132 to meet the specific functional requirements of the packaging film 130 in different application scenarios, thereby improving the application scenarios of photovoltaic modules.

[0056] In the process of preparing the packaging film 130, the packaging film 130 can be prepared by laying an adhesive film with a melting point higher than the melting point of the connecting component 110 on the entire surface of the two opposite sides of the battery cell 100. In some embodiments, the packaging film 130 can also be prepared by using pre-divided adhesive strips on the two opposite sides of the battery cell 100. For example, according to the position of each connecting component 110, a first adhesive strip with a length and width greater than the connecting component 110 is laid above the area where each connecting component 110 is located, and the first adhesive strip covers the connecting component 110 and a partial area of ​​the surface of the battery cell 100, and then a second adhesive strip is laid on the surface of the battery cell 100 not covered by the first adhesive strip, and then the packaging film 130 is formed by lamination, wherein the melting point of the first adhesive strip is greater than the melting point of the connecting component 110.

[0057] The first adhesive strip is used to cover the connecting component 110 and a part of the area on the cell 100, and the melting point of the first adhesive strip is ensured to be greater than the melting point of the connecting component 110, so that the melting time of the first adhesive strip during the lamination process is later than the melting time of the connecting component 110, reducing the probability of the melted adhesive film flowing between the connecting component 110 and the grid line 101, thereby improving the reliability of the photovoltaic module. At the same time, the second adhesive strip can be selected according to the specific functional requirements of the packaging film 130, so that the packaging film can meet the different functional requirements of the packaging film 130 in different scenarios, thereby improving the application scenarios of the photovoltaic module.

[0058] In addition, after forming an adhesive film layer using the first adhesive strip and the second adhesive strip, an adhesive film layer with other functions may be formed on the surface of the formed adhesive film layer away from the battery cell 100 to further improve the adaptability of the packaging film 130 to specific functional requirements.

[0059] In addition, since the adhesive film has a certain fluidity, in order to reduce the probability of the second adhesive strip flowing between the connecting component 110 and the gate line 101 after melting, the width of the first adhesive strip can also be set to 1.5 to 2.75 times the width of the connecting component 110, for example, the width of the first adhesive strip is set to 1.6 times, 1.75 times, 1.8 times, 1.9 times, 2.15 times, 2.25 times, 2.4 times, 2.5 times, 2.65 times or 2.7 times the width of the connecting component 110. The width of the first adhesive strip refers to the spacing between the two side edges of the orthographic projection of the first adhesive strip on the surface of the battery cell 100 in the direction perpendicular to the first direction, and the width of the connecting component 110 refers to the spacing between the two side edges of the orthographic projection of the connecting component 110 on the surface of the battery cell 100 in the direction perpendicular to the first direction.

[0060] In some embodiments, the melting point of the second adhesive film layer 132 is less than or equal to the melting point of the first adhesive film layer 131 .

[0061] After the encapsulation film 130 is prepared by stacking at least two layers of adhesive films on each of the two opposite sides of the cell 100, the function of the second adhesive film layer 132 in the encapsulation film 130 is mainly to meet the specific functional requirements of the encapsulation film 130, and the function of the first adhesive film layer 131 is mainly to prevent the melted adhesive film from flowing between the connecting component 110 and the grid line 101 during the lamination process. In the case that the melting point of the second adhesive film layer 132 is too high, the heating temperature and heating time required during the lamination process will also increase accordingly, which may easily cause the cell 100 to have a large photoelectric conversion performance loss due to excessive high-temperature heating time during the lamination process, thereby affecting the photoelectric conversion efficiency of the photovoltaic module.

[0062] Therefore, in the process of preparing photovoltaic modules, a film with a higher melting point can be selected to form the first film layer 131 of the packaging film 130, and a film with a lower melting point can be selected to form the second film layer 132 of the packaging film 130. This reduces the interference of the preparation of the packaging film 130 on the electrical contact between the connecting component 110 and the gate line 101, while ensuring that the packaging film 130 can meet the functional requirements of specific application scenarios, thereby improving the reliability and adaptability of the photovoltaic modules.

[0063] In some embodiments, the connection member 110 extends along the second direction, and a width of the connection member 110 along a direction perpendicular to the second direction is 0.2 mm to 0.4 mm.

[0064] In the process of setting the connecting component 110, the connecting component 110 is used to connect at least one grid line 101 on any of the two adjacent battery cells 100. Therefore, the connecting component 110 can be set according to the arrangement direction of the plurality of grid lines 101. The angle between the extending direction of the connecting component 110, i.e., the second direction and the first direction, is between 0 and 90 degrees, for example, 5, 10, 15, 25, 30, 45, 60, 78 or 80 degrees. For ease of understanding, the application embodiment is described by taking the extending direction of the connecting component 110 as being consistent with the arrangement direction of the plurality of grid lines 101 as an example, i.e., the angle between the first direction and the second direction is 0.

[0065] The width of the connecting component 110 in the direction perpendicular to the second direction refers to the interval d between the edges of the orthographic projection of the connecting component 110 on the surface of the cell 100 in the direction perpendicular to the second direction. In the case where the width of the connecting component 110 is too small, the area of ​​the electrical contact region between the connecting component 110 and the gate line 101 is too small, the contact resistance is too large, and the resistance value of the connecting component 110 itself is also large. The carriers generated by the cell 100 are lost in the process of being collected to the connecting component 110 and being transmitted through the connecting component 110, thereby reducing the photoelectric conversion efficiency of the photovoltaic module. In the case where the width of the connecting component 110 is too large, the carrier collection and transmission loss of the connecting component 110 is reduced, but the area of ​​the connecting component 110 itself is large, which will cause light shielding to a larger area on the surface of the cell 100, resulting in a decrease in the light energy absorbed by the cell 100, thereby affecting the photoelectric conversion capacity of the cell 100.

[0066] Therefore, in the process of setting the connecting component 110, the width of the connecting component 110 in the direction perpendicular to the extension direction can be set in the range of 0.2mm to 0.4mm, for example, the width of the connecting component 110 is set to 0.22mm, 0.24mm, 0.25mm, 0.28mm, 0.3mm, 0.33mm, 0.35mm, 0.38mm or 0.39mm, etc. By setting the width of the connecting component 110 in a suitable range, the shielding area of ​​the connecting component 110 on the surface of the cell 100 is reduced, the light energy received by the cell 100 is increased, and the photoelectric conversion efficiency of the cell 100 is improved, and the contact area between the connecting component 110 and the gate line 101 is made large enough, the contact resistance between the connecting component 110 and the gate line 101 is effectively reduced, the loss in the process of carrier collection and transmission of the connecting component 110 is reduced, and the photoelectric conversion efficiency of the photovoltaic module is improved.

[0067] In addition, the photovoltaic module includes a plurality of connecting components 110, and the width of each connecting component 110 can be the same or different. For example, a connecting component 110 with a larger width is selected to electrically contact the grid line 101 located in the edge area of ​​the battery cell 100, and a connecting component 110 with a smaller width is selected to electrically contact the grid line 101 located in the central area of ​​the battery cell 100, so as to reduce the edge loss of the battery cell 100 and improve the photoelectric conversion efficiency. The embodiment of the present application does not limit the specific width setting of each connecting component 110.

[0068] In some embodiments, the number of glue dots 121 included in each glue dot group 120 is 3 to 15.

[0069] The function of each glue point 121 in the glue point group 120 is to fix the connection component 110 corresponding to the glue point group 120 at a specific position on the battery cell 100 before lamination, so as to reduce the probability of the connection component 110 being offset during the lamination process. In the case where the number of glue points 121 included in the glue point group 120 is too small, the fixing effect of the glue point group 120 on the connection component 110 is limited, and it may be offset due to external pressure during the lamination process, thereby resulting in poor connection between the connection component 110 and the grid line 101. In the case where the number of glue points 121 included in the glue point group 120 is too large, since the glue points 121 have a certain absorption capacity for light energy, even if the transparency of the glue points 121 is highly improved, in the case where the number of glue points 121 is too large, the light energy obtained by the battery cell 100 will be greatly reduced, thereby affecting the photoelectric conversion efficiency of the battery cell 100.

[0070] Therefore, when setting the glue point groups 120, the number of glue points 121 included in each glue point group 120 can be set within a range of 3 to 15, and the number of glue points 121 included in each glue point group 120 can be the same or different. For example, the number of glue points 121 included in the glue point group 120 is set to 4, 5, 7, 9, 10, 12 or 14. By controlling the number of glue points 121 included in the glue point group 120 within a suitable range, the probability of the connection component 110 being offset during the lamination process is reduced, the fixing effect of the connection component 110 is improved, and at the same time, the absorption of light energy by the glue points 121 is effectively controlled, and the influence of the setting of the glue points 121 on the photoelectric conversion efficiency of the battery cell is reduced.

[0071] In addition, the glue point group 120 can be arranged in a manner that, according to the position to be arranged of the connecting component 110, multiple points are selected at certain intervals in multiple interval areas formed by the spaced grid lines 101 on the surface of the battery cell 100, and then the material for making the glue point 121 is applied to the selected points, and then cured by light, UV light curing or high temperature to form the glue point 121. The material for making the glue point 121 can be cured under certain conditions to adhere to the substrate to form an adhesive with bonding properties, for example, a slurry or paste suitable for coating or introduction composed of inorganic additives, organic additives, organic resins and organic solutions.

[0072] In addition, in the process of setting the glue dots 121, the sizes of the glue dots 121 can be the same or different, wherein the size of each glue dot 121 refers to the area of ​​the orthographic projection of the glue dot 121 on the surface of the battery cell 100 or the maximum length between any two points on the edge of the orthographic projection, and other data characterizing the size. The connecting component 110 needs to be connected to two adjacent battery cells 100 respectively, so during the lamination process, the connecting component 110 is subjected to greater force in the edge area of ​​the battery cell 100, that is, the fixing strength required for the connecting component 110 in the edge area of ​​the battery cell 100 is greater. Therefore, in order to improve the fixing effect of the connecting component 110 in the edge area of ​​the battery cell 100, a larger glue dot 121 can be set in the edge area of ​​the battery cell 100, and a smaller glue dot 121 can be set in the middle area of ​​the battery cell 100. The size of the glue point 121 located in the edge area of ​​the battery cell 100 can be set to 1.2 to 2 times the size of the glue point 121 located in the middle area of ​​the battery cell 100, for example, 1.3 times, 1.5 times, 1.75 times or 1.9 times, etc. In addition, the glue point 121 in the edge area of ​​the battery cell 100 refers to the glue point in the glue point group 120 adjacent to the edge of the battery cell 100 along the arrangement direction of the adjacent battery cells 100.

[0073] refer to Figures 1 to 6 ,in, Figure 6FIG. 1 is another schematic diagram of a cross-sectional structure of a local area a. In some embodiments, the connecting component 110 includes an inner core 111 and a wrapping layer 112, the wrapping layer 112 covers the inner core 111, and the melting point of the wrapping layer 112 is a first temperature.

[0074] The function of the connecting component 110 is to connect adjacent cells 100 in series along the arrangement direction of the cells 100 to collect and transmit carriers. The connecting component 110 can be electrically connected to the grid lines 101 on the cells 100 by means of a melted wrapping layer 112 that electrically contacts the grid lines 101, collects the carriers on the grid lines 101 to the inner core 111 through the wrapping layer 112, and then transmits the carriers through the inner core 111 that has conductive capability.

[0075] During the lamination process, the inner core 111 is usually made of a material with a relatively high melting point, such as copper, aluminum, aluminum alloy, etc. If the inner core 111 is heated to melt, the cell 100 is easily subjected to irreversible photoelectric conversion performance loss due to the excessively high temperature. Therefore, in order to ensure the carrier transmission capability of the connecting component 110 and the reliability of the connection with the grid line 101, a wrapping layer 112 with a melting point of the first temperature and a certain conductivity can be coated on the outer surface of the inner core 111 to form the connecting component 110. Thus, the wrapping layer 112 will melt and flow onto the grid line 101 after the temperature reaches the first temperature during the lamination process, so that the inner core 111 is in electrical contact with the grid line 101 through the wrapping layer 112. By using the inner core 111 and the wrapping layer 112 to form the connecting component 110, the heating temperature during the lamination process is reduced, and the damage to the photoelectric conversion performance of the cell 100 caused by the excessively high temperature during the lamination process is avoided. At the same time, it is ensured that the grid line 101 can establish good electrical contact with the connecting component 110, thereby improving the reliability of the photovoltaic module.

[0076] In addition, in the direction perpendicular to the surface where the wrapping layer 112 contacts the inner core 111, if the thickness of the wrapping layer 112 is too large, the volume of the melted wrapping layer 112 is likely to be too large, forming an excessively large shading area on the surface of the cell 100, affecting the photoelectric conversion efficiency of the cell 100, while if the thickness of the wrapping layer 112 is too small, the volume of the melted wrapping layer 112 is too small, and it may not be able to completely fill the cavity between the inner core 111 and the grid line 101, resulting in a portion that is not electrically contacted between the inner core 111 and the grid line 101, reducing the carrier collection ability of the connecting component 110, and affecting the photoelectric conversion efficiency of the photovoltaic module. Therefore, the thickness of the wrapping layer 112 can be set to 10μm to 15μm, for example, 11μm, 12.5μm, 13μm or 14.5μm, etc. Among them, the thickness of the wrapping layer 112 refers to the interval between the surface where the wrapping layer 112 contacts the inner core 111 and the surface of the wrapping layer 112 away from the inner core 111.

[0077] In some embodiments, the connection component 110 is a soldering tape, which may be composed of a conductive core such as a copper core, an aluminum core, or an aluminum alloy core, and a wrapping layer that covers the conductive core, has a melting point of the first temperature, and has a certain conductivity, such as a tin-plated layer or a tin-coated layer.

[0078] In some embodiments, the cover plate 140 may be a glass cover plate, a plastic cover plate, or the like with a light-transmitting function. Specifically, the surface of the cover plate 140 facing the packaging film 130 may be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0079] In the photovoltaic module provided by the embodiment of the present application, when adjacent cells 100 are connected in series, the glue point group 120 is used to fix the connecting component 110 above the grid line 101 before lamination, so as to avoid the displacement of the connecting component 110 during the lamination process, and improve the accuracy and safety of the electrical contact between the connecting component 110 and the grid line 101 during the series connection of the cells 100; the connecting component 110 with a melting point of the first temperature is used to electrically contact the grid lines 101 on two adjacent cells 100 respectively, so as to realize the series connection of adjacent cells 100, and the part close to the cell 100 is selected. The photovoltaic module is prepared by using a packaging film 130 with a melting point of the second temperature, and the second temperature is greater than the first temperature, which ensures that the melting time of the adhesive film close to the battery cell 100 during the lamination process will be later than the melting time of the connecting component 110, so that the connecting component 110 can melt earlier than the adhesive film and fully make electrical contact with the gate line 101, which greatly avoids the insulation problem between the connecting component 110 and the gate line 101 caused by the adhesive film flowing between the connecting component 110 and the gate line 101 after melting, thereby improving the electrical connection reliability and welding effect between the gate line 101 and the connecting component 110.

[0080] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the claims. Any technical personnel in this field may make several possible changes and modifications without departing from the spirit and scope of the present application without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A photovoltaic module, characterized in that: include: A plurality of battery cells, each of the plurality of battery cells comprising a plurality of grid lines arranged at intervals along a first direction; A plurality of connecting components, each of the plurality of connecting components is in electrical contact with at least one of the plurality of grid lines of any two adjacent battery cells, and the melting point of the connecting component is a first temperature; the connecting component comprises an inner core and a wrapping layer, the wrapping layer covers the inner core, and the melting point of the wrapping layer is the first temperature; the thickness of the wrapping layer is 10 μm to 15 μm; A plurality of glue point groups, each of the plurality of glue point groups is located on the surface of a corresponding one of the battery cells, the glue point group includes a plurality of glue points, the plurality of glue points are in contact and connected with a corresponding one of the connecting components of the glue point group, the plurality of glue points include edge glue points adjacent to the edge of the battery cell and middle glue points located between the edge glue points, the ratio between the glue point size of the edge glue point and the glue point size of the middle glue point is 1.2 to 2, wherein the glue point size includes the area of ​​the positive projection of the glue point on the battery cell surface or the maximum interval between any two points on the positive projection edge of the glue point on the battery cell surface; A packaging film, wherein the packaging film covers the surfaces of the plurality of battery cells and the surfaces of the plurality of connecting components; the packaging film comprises a first adhesive strip located on the connecting component and a second adhesive strip on the surface of the battery cell, wherein the second adhesive strip is located on the surface of the battery cell not covered by the first adhesive strip, and the first adhesive strip covers the connecting component; The melting point of the portion of the first adhesive strip adjacent to the plurality of battery cells is a second temperature, and the second temperature is greater than the first temperature; The temperature difference between the first temperature and the second temperature is 20°C to 40°C; the first temperature is 130°C to 145°C; the second temperature is 150°C to 185°C; The length and width of the first rubber strip are greater than the length and width of the connecting component, and the width of the first rubber strip is 1.5 to 2.75 times the width of the connecting component; A cover plate covers a surface of the packaging film away from the plurality of battery cells.

2. The photovoltaic module according to claim 1, characterized in that: The packaging film includes POE film, EVA film, PVB film, EPE film or EP film.

3. The photovoltaic module according to claim 1, characterized in that: The connecting component extends along the second direction, and in a direction perpendicular to the second direction, a width of the connecting component is 0.2 mm to 0.4 mm.

4. The photovoltaic module according to claim 1, characterized in that: The number of glue dots contained in each of the glue dot groups is 3 to 15.

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