A back contact photovoltaic module without a main grid and a manufacturing method thereof

Abstract

The present application relates to a kind of main gridless back contact photovoltaic module and its preparation method, belong to battery and module technical field, battery module includes: support frame, frame, battery string, junction box, cover plate, battery string includes anode fine grid line, negative fine grid line, tin paste point, insulating glue point and interconnection line, the anode fine grid line and the negative fine grid line interval arrangement, the tin paste point and the insulating glue point are staggered and arranged on the anode fine grid line and the negative fine grid line, the interconnection line is laid on the tin paste point and the insulating glue point, the interconnection line is fixed by insulating glue point and the tin paste point, so as to interconnect several cell pieces, and form battery string by fixing.The back contact cell back surface is designed without main grid, only there is anode fine grid line and negative fine grid line arranged at intervals, without complex design, battery is used without main grid paste, not only can greatly reduce material cost, but also because of saving main grid paste printing, sintering process, reduce equipment and manpower investment.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic and module technology, specifically, it relates to a gridless back-contact photovoltaic module and its preparation method. Background Technology

[0002] Current back-contact photovoltaic modules have drawbacks such as large design area of ​​main busbar and pads, and high silver paste consumption. Furthermore, due to their single-sided characteristics, they have a high degree of warping in the welding section of the module manufacturing process, and are prone to defects such as microcracks and cell cracks in welding, layout, and lamination processes. Therefore, the busbar-less technology of heterojunction cells was developed.

[0003] However, in current applications, gridless photovoltaic modules lack conventional grid and pad designs, and their fine grid lines have low silver content. If conventional stringing methods are still used, effective welding cannot be achieved, and the fine grid lines are prone to breakage and corrosion. To address this issue, existing gridless solutions primarily employ lamination welding, with lamination temperatures typically ranging from 140℃ to 150℃. The melting points of the interconnect materials used must also fall within this range. Given the hotspot effect of the module, the temperature at the hotspot point must be limited below the material's melting point to prevent the interconnect lines from remelting during photovoltaic module operation, causing desoldering. Therefore, the hotspot temperature of the photovoltaic module is limited, placing higher demands on the module and affecting its versatility. Summary of the Invention

[0004] To address the technical problem in the background art where the hot spot effect exists due to the welding method of the gridless photovoltaic module, and the cells will melt again during the operation of the photovoltaic module if the temperature is not properly controlled, resulting in desoldering, the present invention provides a gridless back contact battery module and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A gridless back-contact photovoltaic module includes: a support frame, a frame, a cell string, a junction box, and a cover plate. The cell string includes positive electrode fine grid lines, negative electrode fine grid lines, solder paste dots, insulating adhesive dots, and interconnecting wires.

[0007] The positive and negative fine grid lines are arranged at intervals, and the solder paste dots and insulating adhesive dots are alternately arranged on the positive and negative fine grid lines. The interconnecting lines are laid on the solder paste dots and the insulating adhesive dots. The interconnecting lines are fixed by the insulating adhesive dots and the solder paste dots, thereby interconnecting several battery cells to form a battery string.

[0008] The battery string has encapsulation material on both sides, and the cover plate is disposed on the outside of the encapsulation material. The upper and lower sides of the battery string are respectively connected to the cover plate. The cover plate includes an upper cover plate and a lower cover plate. The upper cover plate and the lower cover plate are supported and fixed by the frame. The battery string is installed inside the frame. The junction box is connected to the battery string through a connecting wire and is disposed outside the frame.

[0009] The support frame includes a first support frame and a second support frame. The first support frame includes a horizontal bar and a vertical bar. One end of the horizontal bar is movably connected to the cover plate, and the vertical bar is movably connected to the second support frame. The horizontal bar and the vertical bar form an angle.

[0010] Furthermore, a front adhesive film and glass are sequentially applied to the upper surface of the battery string, and a rear adhesive film and a backplate are sequentially applied to the lower surface of the battery string.

[0011] Furthermore, the insulating adhesive is a UV adhesive or a heat-sensitive adhesive.

[0012] Furthermore, the interconnecting lines are laid from left to right, corresponding to the negative and positive terminals of the fine grid lines, respectively.

[0013] Furthermore, the solder paste dots and the insulating adhesive dots are printed perpendicularly on the fine grid lines.

[0014] Furthermore, the front adhesive film and the rear adhesive film are an integral film or two separate films, and the adhesive film on the battery side is a low-flow film.

[0015] Furthermore, the battery assembly consists of glass, a front adhesive film, the battery string, a rear adhesive film, and a backplate, arranged sequentially from front to back.

[0016] On the other hand, the present invention also provides a method for preparing a gridless back-contact photovoltaic module, which includes the following steps:

[0017] According to the graphic design, solder paste and insulating glue are printed, dried and pre-cured, and then the battery series connection process is carried out.

[0018] Several battery cells are interconnected to form a battery string;

[0019] After the battery string is formed, a pre-adhesive film and a post-adhesive film are applied to the upper and lower surfaces of the battery string, respectively. Glass is applied to the upper surface of the pre-adhesive film, and a back sheet is applied to the lower surface of the post-adhesive film to form the part to be laminated.

[0020] The laminated component is hot-laminated. After lamination and cooling, a laser is used to heat and solder the solder paste and interconnects of the laminated component through the medium. The melting point range of the solder paste and interconnects is 160-200℃.

[0021] Furthermore, the battery series connection process includes the following steps:

[0022] Interconnect wires are laid on top of solder paste and insulating adhesive, and then the insulating adhesive is cured by low temperature or ultraviolet irradiation, thereby fixing the interconnect wires.

[0023] Furthermore, in the process of printing solder paste and insulating adhesive according to the graphic design, the solder paste and the insulating adhesive are printed alternately.

[0024] The beneficial effects of this invention are:

[0025] 1. The present invention discloses a gridless back-contact photovoltaic module. The back surface of the back contact cell has no grid design, only spaced positive and negative fine grid lines. The design is simple and eliminates the use of grid paste, which can not only significantly reduce material costs, but also reduce equipment and manpower investment by eliminating the printing and sintering process of grid paste.

[0026] 2. The present invention discloses a method for manufacturing a gridless back-contact photovoltaic module. This method involves first stringing together solar cells to form a laminate, then placing the laminate in a laminator for lamination. After lamination and cooling, a laser is used to heat and weld the solder paste and interconnects of the laminate. This post-lamination welding method, since it eliminates the need for separate heating of the solder paste and interconnects before lamination, and laser welding is performed only after lamination, effectively reduces the adverse effects of cell warping and effectively solves the problem of molten material in hot spots during lamination welding. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of a gridless back-contact photovoltaic module in an embodiment of the present invention.

[0029] Figure 2 This is a top view of the overall structure of a gridless back-contact photovoltaic module in an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram of the exploded structure of the battery string in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structural layout of the fine grid lines in the battery string in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the printing layout of solder paste dots and insulating adhesive dots in a battery string in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structural layout of the fine grid lines for the positive and negative electrodes in a battery string, as shown in an embodiment of the present invention.

[0034] Figure 7 A flowchart illustrating the overall steps of one embodiment of a method for fabricating a gridless back-contact photovoltaic module;

[0035] Figure 8 This is a flowchart illustrating the overall steps of another embodiment of a method for fabricating a gridless back-contact photovoltaic module according to the present invention.

[0036] The attached diagram lists the components represented by each number as follows:

[0037] 110. Positive electrode fine grid line; 120. Negative electrode fine grid line; 2. Solder paste dot; 3. Insulating adhesive dot; 4. Interconnect line; 5. Battery string; 6. Glass; 7. Front adhesive film; 8. Rear adhesive film; 9. Backplate; 10. Frame; 11. Junction box; 12. Support frame; 121. First support frame; 122. Second support frame; 123. Horizontal bar; 124. Vertical bar; 13. Cover plate; 131. Upper cover plate; 132. Lower cover plate; 14. Encapsulation material; 15. Connecting wire. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To address the high cost of conventional back-contact batteries as mentioned in the background art, this application proposes a busbar-less design to reduce silver paste consumption. Therefore:

[0040] This invention provides a gridless back-contact battery assembly, such as... Figure 1 As shown, the device includes a support frame 12, a frame 10, a battery string 5, a junction box 11, and a cover plate 13. The battery string 5 includes a positive electrode fine grid line 110, a negative electrode fine grid line 120, solder paste dots 2, insulating glue dots 3, and interconnecting wires 4, wherein:

[0041] like Figures 4 to 6As shown, the positive electrode fine grid line 110 and the negative electrode fine grid line 120 are arranged at intervals. The solder paste dots 2 and the insulating adhesive dots 3 are disposed on the upper side of the positive and negative electrode fine grid lines 120. The solder paste dots 2 and the insulating adhesive dots 3 are arranged alternately on the positive electrode fine grid line 110 and the negative electrode fine grid line 120. The interconnecting line 4 is laid on the solder paste dots 2 and the insulating adhesive dots 3. The insulating adhesive dots 3 are cured by low temperature or ultraviolet light irradiation, thereby fixing the interconnecting line 4. Based on this, several battery cells are interconnected to form a battery string 5.

[0042] like Figure 2 As shown, the battery string 5 has encapsulation material 14 on both sides, and the cover plate 13 is disposed on the outside of the encapsulation material 14. The upper and lower sides of the battery string 5 are respectively connected to the cover plate 13. The cover plate 13 includes an upper cover plate and a lower cover plate. The upper cover plate and the lower cover plate are supported and fixed by the frame 10. The battery string 5 is installed inside the frame 10. The junction box 11 is connected to the battery string 5 through the connecting line 15 and is disposed outside the frame 10.

[0043] like Figure 1 As shown, the support frame 12 includes a first support frame 121 and a second support frame 122. The first support frame 121 includes a horizontal bar 123 and a vertical bar 124. One end of the horizontal bar 123 is movably connected to the cover plate 13, and the vertical bar 124 is movably connected to the second support frame 122. The horizontal bar 123 and the vertical bar 124 form an angle.

[0044] In this embodiment, the cover plate 13 is disposed on the outside of the encapsulation material 14. Specifically, a photovoltaic module refers to a smallest indivisible photovoltaic cell assembly that has internal connections and encapsulation and can independently provide DC power output. A photovoltaic module is formed by connecting several cells in series via electrical connectors. A cell is a device that converts light energy into electrical energy using the photovoltaic effect, and is also the smallest unit of photoelectric conversion.

[0045] like Figure 3 As shown, the upper surface of the battery string 5 is sequentially covered with a front adhesive film 7 and a glass 6, and the lower surface of the battery string 5 is sequentially covered with a rear adhesive film 8 and a back plate 9.

[0046] Specifically, the encapsulation material 14 is a photovoltaic encapsulation film, which is generally an EVA (Ethylene-Vinyl-Acetate-Copolymer) film or a POE (Polyolefin elastomer) film.

[0047] The frame 10, as the outermost encapsulation structure of the photovoltaic module, is lightweight and meets the characteristic requirements of the photovoltaic module. The frame 10 improves the overall mechanical strength of the photovoltaic module, facilitating installation and transportation. The frame 10 is made of aluminum alloy and protects the edges of the cover plate 13, working in conjunction with silicone edging to enhance the sealing performance of the photovoltaic module. The junction box 11 transmits the current generated within the photovoltaic module to external wiring.

[0048] Specifically, the movable connection refers to a connection method that allows for relative movement, such as a hinge.

[0049] More specifically, in locations where installation on rooftops is inconvenient, such as on vertical walls, the entire photovoltaic module can be mounted on the wall using the vertical rod 124. At the same time, the angle of the solar cells can be adjusted using the second support frame 122 to adapt to the angle of sunlight.

[0050] In a preferred embodiment of this application, the angle formed by the horizontal bar 123 and the vertical bar 124 is preferably 90°.

[0051] Furthermore, in the embodiments of this application, the insulating adhesive is a UV adhesive or a heat-sensitive adhesive.

[0052] In the embodiments of this application, such as Figure 5 As shown, from the front view of the battery string 5, the interconnecting lines 4 from left to right are designed as negative-positive-negative...positive. Based on the arrangement of the positive and negative fine grid lines 110 and 120, solder paste dots 2 and insulating adhesive dots 3 are printed vertically on the fine grid lines. The solder paste assists in soldering, and the insulating adhesive, besides fixing the interconnecting lines 4, also plays a crucial role in preventing short circuits. For example, in one specific embodiment of this application, when the interconnecting line 4 is the positive terminal, the negative fine grid line 120 points it passes through must be isolated using insulating adhesive.

[0053] After the battery string 5 is formed, the front adhesive film 7 and the rear adhesive film 8 can be an integral film or two separate films. The side of the front adhesive film 7 and the rear adhesive film 8 that contacts the battery has low fluidity to prevent the front adhesive film 7 or the rear adhesive film 8 from having excessive fluidity during lamination, which would cause the interconnect line 4 to shift. The adhesive film on the side that contacts the battery is a low-fluidity film, while the side that does not contact the battery can be a conventional adhesive film.

[0054] The battery string 5 disclosed in this application only has alternating positive electrode fine grid lines 110 and negative electrode fine grid lines 120, without complex design. The battery eliminates the use of main grid paste, which can not only significantly reduce material costs, but also reduce equipment and manpower investment by eliminating the printing and sintering process of main grid paste.

[0055] Specifically, the fine grid lines, also known as photovoltaic ribbons or solder ribbons, are used to electrically connect to the electrodes of the solar cells to collect the current converted by the cells. They are the components that realize the electrical connection between solar cells and are the core electrical connection components in a photovoltaic module. The quality of the fine grid lines directly affects the electricity collection efficiency of the photovoltaic module. In some embodiments, such as... Figure 2 As shown, the connecting line 15 includes an interconnect strip and a busbar. The interconnect strip is used to connect the battery cells in series; an interconnect strip is soldered to the back of each battery cell, thereby connecting several battery cells together to form a battery string 5. The busbar is the carrier connecting the battery strings 5. The busbar connects the series-connected battery strings 5 ​​together and finally leads out the positive and negative terminals to the junction box 11. In some embodiments, both the interconnect strip and the busbar are tinned copper strips.

[0056] In one embodiment of this application, a gridless back-contact battery assembly is provided, such as... Figure 3 As shown, the aforementioned gridless back-contact photovoltaic module includes a glass 6, a front encapsulating film 7, a battery string 5, a rear encapsulating film 8, and a backsheet 9, arranged sequentially from front to back.

[0057] In this embodiment, a gridless back-contact solar module further includes a frame 10, with the battery string 5 installed inside the frame. A junction box 11 is also provided outside the frame, and the current generated by the battery string 5 is led to the junction box 11. In this embodiment, the weight power density of the solar module is greater than or equal to 17 W / kg and less than or equal to 18.5 W / kg. Because the solar module is too heavy, the requirements for the lightness of the supporting materials increase, and transportation costs increase, thereby increasing the overall installation cost. Furthermore, the higher the power of the solar module, the higher the requirements for the photoelectric conversion efficiency of the solar cells, increasing the manufacturing cost of the solar module. Therefore, in this embodiment, the weight power density of the solar module is controlled within the range of 17 W / kg to 18.5 W / kg, which can meet the bearing capacity of common profiles on the market and keep the cost of the photovoltaic module within the range of power generation revenue. Specifically, in this embodiment, the weight power density of the solar module can be 17 W / kg, 17.5 W / kg, 18 W / kg, or 178.5 W / kg.

[0058] On the other hand, to address the issue of high warpage during battery welding, instead of series welding, lamination welding or post-lamination welding is employed. The hot spot or melting point temperatures of the battery, encapsulant film, backsheet 9, and interconnects 4 are set. Therefore, this application provides a method for fabricating a gridless back-contact battery assembly, aiming to solve the problem of high warpage during welding of the gridless battery string 5. Figure 7 As shown, it includes the following steps:

[0059] Step S1: Print solder paste and insulating adhesive according to the graphic design, dry and pre-cur, and then carry out the battery series connection process;

[0060] Step S2: Interconnect several battery cells to form a battery string;

[0061] Step S3: After the battery string is formed, a pre-adhesive film and a post-adhesive film are applied to the upper and lower surfaces of the battery string, respectively. Glass is applied to the upper surface of the pre-adhesive film, and a back sheet is applied to the lower surface of the post-adhesive film to form the laminate.

[0062] Step S4: Perform hot lamination on the component to be laminated. After lamination and cooling, use a laser to heat the solder paste and interconnects of the laminated component by passing through the medium. In this embodiment, the melting point range of the solder paste and interconnects is 160-200℃. In this embodiment, the optimal melting point is 160℃.

[0063] In another embodiment of this application, such as Figure 8 As shown, in step S1, according to the graphic design, solder paste and insulating adhesive are printed and dried for pre-curing, and then the battery series connection process is carried out. The battery series connection process includes: laying interconnecting lines on the solder paste and insulating adhesive, and then using low temperature or ultraviolet irradiation to cure the insulating adhesive, thereby fixing the interconnecting lines.

[0064] Step S2: Interconnect several battery cells to form a battery string;

[0065] Step S3: After the battery string is formed, a pre-adhesive film and a post-adhesive film are applied to the upper and lower surfaces of the battery string, respectively. Glass is applied to the upper surface of the pre-adhesive film, and a back sheet is applied to the lower surface of the post-adhesive film to form the laminate.

[0066] Step S4: Perform hot lamination on the component to be laminated. After lamination and cooling, use a laser to heat the solder paste and interconnects of the laminated component by passing through the medium. In this embodiment, the melting point range of the solder paste and interconnects is 160-200℃. In this embodiment, the optimal melting point is 160℃.

[0067] First, the melting points of the solder paste and interconnects are set above the lamination temperature (140-150℃). During the lamination process, the solder paste and interconnects do not melt or undergo any changes; they only have physical surface contact with the battery, preventing alloy soldering (i.e., the desired soldering effect). Additionally, the adhesive film melts normally and forms covalent bonds with the contacted materials.

[0068] In this application embodiment, a post-lamination soldering method is proposed. During the lamination process, the solder paste and interconnects do not undergo physical or chemical changes and do not form a soldering effect. Instead, the adhesive film undergoes melting and cross-linking. After lamination and cooling, a laser is used to precisely heat the solder paste and interconnects of the laminated component through the glass and adhesive film, achieving the soldering purpose. To avoid the backplane and adhesive film decomposing or melting due to the laser soldering temperature after lamination, the melting point range of the solder paste and interconnects is limited to 160-200℃.

[0069] Conventional heating methods use infrared lamps, which radiate heat and provide localized heating. However, the laser heating method disclosed in this application works by irradiating an object with a laser beam. The object absorbs the laser energy and generates heat. By adjusting the laser's parameters, the energy and positioning of the laser beam can be controlled, ultimately achieving precise heating.

[0070] Post-laminar welding can effectively reduce the adverse effects of cell warping and avoid the disadvantages of hot spots and molten material in lamination welding.

[0071] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0072] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0073] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0074] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0075] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0076] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A gridless back-contact photovoltaic module, characterized in that, include: The components include a support frame, a frame, a battery string, a junction box, and a cover plate. The battery string comprises battery cells, positive electrode fine grid lines, negative electrode fine grid lines, solder paste dots, insulating adhesive dots, and interconnecting wires. The positive and negative fine grid lines are arranged at intervals, and the solder paste dots and insulating adhesive dots are alternately arranged on the positive and negative fine grid lines. The interconnecting lines are laid on the solder paste dots and the insulating adhesive dots. The interconnecting lines are fixed by the insulating adhesive dots and the solder paste dots to connect several battery cells, so as to form a battery string. The battery string has encapsulation material on both sides, and the cover plate is disposed on the outside of the encapsulation material. The upper and lower sides of the battery string are respectively connected to the cover plate. The cover plate includes an upper cover plate and a lower cover plate. The upper cover plate and the lower cover plate are supported and fixed by the frame. The battery string is installed inside the frame. The junction box is connected to the battery string through a connecting wire and is disposed outside the frame. The upper surface of the battery string is sequentially covered with a front adhesive film and glass, and the lower surface of the battery string is sequentially covered with a rear adhesive film and a backplate. The front adhesive film and the rear adhesive film are an integral film or two separate films, and the adhesive film on the side in contact with the battery is a low-flow film. The support frame includes a first support frame and a second support frame. The first support frame includes a horizontal bar and a vertical bar. One end of the horizontal bar is movably connected to the cover plate, and the vertical bar is movably connected to the second support frame. The horizontal bar and the vertical bar form an angle. The component is prepared as follows: After the battery string is formed, a pre-adhesive film and a post-adhesive film are applied to the upper and lower surfaces of the battery string, respectively. Glass is applied to the upper surface of the pre-adhesive film, and a back sheet is applied to the lower surface of the post-adhesive film to form the part to be laminated. The laminated component is hot-laminated. After lamination and cooling, a laser is used to heat and solder the solder paste and interconnects of the laminated component through the medium. The melting point range of the solder paste and interconnects is 160-200℃.

2. The gridless back-contact photovoltaic module according to claim 1, characterized in that, The upper surface of the battery string is sequentially covered with a front adhesive film and glass, and the lower surface of the battery string is sequentially covered with a rear adhesive film and a backplate.

3. A gridless back-contact photovoltaic module according to claim 1, characterized in that, The insulating adhesive is a UV adhesive or a heat-sensitive adhesive.

4. A gridless back-contact photovoltaic module according to claim 1, characterized in that, The interconnecting lines are laid from left to right, corresponding to the negative and positive terminals of the fine grid lines, respectively.

5. A gridless back-contact photovoltaic module according to claim 1, characterized in that, The solder paste dots and the insulating adhesive dots are printed perpendicularly on the fine grid lines.

6. A method for fabricating a gridless back-contact photovoltaic module, characterized in that, The method for preparing a gridless back-contact photovoltaic module according to any one of claims 1 to 5 includes the following steps: According to the graphic design, solder paste and insulating glue are printed, dried and pre-cured, and then the battery series connection process is carried out. The battery series connection process includes the following steps: laying interconnecting wires on solder paste and insulating adhesive, and then using low temperature or ultraviolet irradiation to cure the insulating adhesive, thereby fixing the interconnecting wires; Several battery cells are interconnected to form a battery string; After the battery string is formed, a pre-adhesive film and a post-adhesive film are applied to the upper and lower surfaces of the battery string, respectively. Glass is applied to the upper surface of the pre-adhesive film, and a back sheet is applied to the lower surface of the post-adhesive film to form the part to be laminated. The laminated component is hot-laminated. After lamination and cooling, a laser is used to heat and solder the solder paste and interconnects of the laminated component through the medium. The melting point range of the solder paste and interconnects is 160-200℃.

7. The method for fabricating a gridless back-contact photovoltaic module according to claim 6, characterized in that, In the process of printing solder paste and insulating adhesive according to the graphic design, the solder paste and the insulating adhesive are printed alternately.

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