Photovoltaic module and method of manufacturing the same

Abstract

This disclosure relates to a photovoltaic module and its manufacturing method. The photovoltaic module includes: multiple cell strings, multiple busbars, and insulating buffer adhesive. Each cell string includes multiple back-contact cells, and adjacent back-contact cells are connected in series via solder strips. The busbars are located on the back side of the cell strings and are used to connect at least two cell strings. The insulating buffer adhesive is disposed between the cell strings and the busbars to insulate and isolate the busbars and the grid lines on the back-contact cells with polarities opposite to those of the busbars. By providing the insulating buffer adhesive, when the busbars are located on the back side of the cells, they can be separated from the grid lines of different polarities, reducing the risk of short circuits in the cells. It also acts as a buffer during cell string stacking and lamination, reducing the risk of cell cracking.

Description

Technical Field

[0001] This disclosure relates to the field of photovoltaic module technology, and more specifically, to a photovoltaic module and its preparation method. Background Technology

[0002] In related technologies, the busbars in back-contact photovoltaic modules can be directly soldered onto the back solder strip. Insulating strips are used to isolate the busbars from the irregularly shaped solder strips to prevent short circuits. The insulating strips require high placement precision; the openings in the insulating strips must be aligned with the solder strips. Misalignment will cause incomplete soldering, and severe misalignment can lead to short circuits / open circuits in the solar cells. Furthermore, during aging tests, the insulating strips are more prone to delamination, which can also cause short circuits in the solar cells. Summary of the Invention

[0003] The purpose of this disclosure is to provide a photovoltaic module and a method for manufacturing the same, which can reduce the risk of short circuits in the solar cells and also act as a buffer during the stacking and lamination of solar cell strings to reduce the risk of cell cracking, thereby at least partially solving the problems in the related technologies.

[0004] To achieve the above objectives, a first aspect of this disclosure provides a photovoltaic module, comprising: Multiple battery strings, each battery string comprising multiple back-contact solar cells, adjacent back-contact solar cells being connected in series via solder strips; Multiple busbars, located on the backlight side of the battery strings, for connecting at least two of the battery strings; and An insulating buffer adhesive is disposed between the battery string and the busbar to insulate and isolate the busbar and the grid lines on the back-contact battery cell that have a polarity opposite to that of the busbar.

[0005] Optionally, the busbar includes an end busbar and a middle busbar. Along the first direction, the multiple battery strings are divided into a first battery string group and a second battery string group. The multiple battery strings in the first battery string group and the second battery string group are connected in series, and the first battery string group and the second battery string group are connected in parallel through the middle busbar.

[0006] Optionally, the insulating buffer adhesive is provided between the intermediate busbar and the back-contact battery cells in the first battery string group and / or the second battery string group that are adjacent to the intermediate busbar.

[0007] Optionally, each of the back-contact battery cells is provided with the insulating buffer adhesive at a predetermined position.

[0008] Optionally, an insulating decorative strip is also provided between the intermediate busbar and the insulating buffer adhesive.

[0009] Optionally, the solder strip in the first battery string group connected to the intermediate busbar is located above the solder strip in the second battery string group connected to the intermediate busbar. The intermediate busbar is located on the back-light surface of the back-contact battery cell closest to the intermediate busbar in the second battery string group. The solder strip in the second battery string group is connected to the bottom surface of the intermediate busbar. The solder strip in the first battery string group is bent and connected to the top surface of the intermediate busbar. The insulating buffer adhesive is disposed between the solder strip in the second battery string group connected to the intermediate busbar and the back-contact battery cell closest to the intermediate busbar.

[0010] Optionally, the first battery string group and the second battery string group are on the same plane, the solder strips in the first battery string group connected to the intermediate busbar and the solder strips in the second battery string group connected to the intermediate busbar are respectively connected to the top surface of the intermediate busbar, and the insulating buffer adhesive is disposed on the bottom surface of the intermediate busbar and between the back contact battery cells disposed adjacent to the intermediate busbar.

[0011] Optionally, the end busbar is disposed on the backlight surface of the first battery string group and the second battery string group away from the intermediate busbar, and the insulating buffer adhesive is provided between the end busbar and the back contact battery cells of the first battery string group and the second battery string group adjacent to the end busbar.

[0012] Optionally, the distance between the edge of the busbar and the edge of the insulating buffer is not less than 2 mm.

[0013] Optionally, the thickness of the insulating buffer adhesive is D, where 40μm ≥ D ≥ 30μm.

[0014] Optionally, the spacing between adjacent battery strings connected to the intermediate busbar can be a positive or negative spacing.

[0015] Optionally, the positive spacing between two adjacent battery strings connected to the intermediate busbar is 2mm to 4mm, or The negative spacing between two adjacent battery strings connected to the intermediate busbar is -0.8mm to -1.8mm.

[0016] Optionally, the back-contact solar cells in the battery string are arranged with a single screen electrode, and the screen for the back-contact solar cells is the same as the screen for the insulating buffer adhesive.

[0017] A second aspect of this disclosure provides a method for preparing a photovoltaic module, the method comprising: Multiple battery strings are provided, each battery string comprising multiple back-contact cells connected in series via solder strips. Provide insulating buffer adhesive, which is placed at a predetermined position in the battery string that contacts the battery cells on the back. Multiple busbars are provided, which are set at preset positions on the back contact battery and are welded to the adjacent battery string; The welded battery strings and busbars are laminated and encapsulated to form photovoltaic modules.

[0018] Optionally, in addition to placing the insulating buffer adhesive at a preset position on the back contact cell of the battery string, the insulating buffer adhesive may also be placed at the preset position on the back contact cell by printing.

[0019] Optionally, the busbar includes an end busbar and a middle busbar. Along the first direction, multiple battery strings are divided into a first battery string group and a second battery string group. Multiple battery strings in the first battery string group and the second battery string group are connected in series, and the first battery string group and the second battery string group are connected in parallel through the middle busbar. The system provides multiple busbars, which are positioned at predetermined locations on the back contact batteries. It also includes an insulating buffer layer between the intermediate busbar and the back contact battery cells in the first battery string group and / or the second battery string group adjacent to the intermediate busbar.

[0020] Optionally, the method further includes: the spacing between the two battery strings connected to the intermediate busbar is a positive spacing; the lead-out solder strips in the first battery string group and the second battery string group are bent in the direction away from the back contact battery cell; the intermediate busbar is placed in the area enclosed by the corresponding back contact battery cell in the first battery string group, the corresponding back contact battery cell in the second battery string group, and the solder strip; and the welding head presses and welds the composite of the intermediate busbar and the battery cell.

[0021] Optionally, the method further includes: providing an insulating decorative strip between the intermediate busbar and the insulating buffer adhesive.

[0022] Optionally, the method further includes: the spacing between the two battery strings connected to the intermediate busbar is a negative spacing. The lead-out solder strips in the first and second battery string groups are bent in the direction away from the back-contact battery cells. The intermediate busbar is vertically positioned between the first and second battery string groups, with the lowest point of the intermediate busbar being a first preset distance higher than the back-contact battery cell at the higher position. The welding head welds the vertical intermediate busbar and the corresponding welding strip. After welding, the pressure roller is used to tilt the welded intermediate busbar toward the side where the insulating buffer adhesive is applied.

[0023] Optionally, the method further includes: a first preset distance greater than 2 mm, and / or The bending angle of the lead-out solder strip is greater than 80°, where the bending angle is the angle between the solder strip and the back surface of the back contact solar cell.

[0024] Optionally, the method further includes: an end busbar is disposed on the backlight surface of the first battery string group and the second battery string group on the side away from the intermediate busbar, and an insulating buffer adhesive is provided between the end busbar and the back contact battery cells of the first battery string group and the second battery string group adjacent to the end busbar.

[0025] Optionally, the method further includes: bending the lead-out solder strips in the first battery string group and the second battery string group toward the direction away from the back contact battery cell; setting the end busbar parallel to the bending direction of the corresponding solder strips in the first battery string group and the second battery string group; welding the inclined end busbar and solder strip with a welding head; and using a pressure roller to turn the welded end busbar toward the side of the back contact battery cell where the insulating buffer adhesive is provided.

[0026] Optionally, the method further includes: bending the lead-out solder strips in the first battery string and the second battery string toward the direction away from the back contact battery cell. The end busbars are positioned at preset locations corresponding to the back-contact solar cells in the first battery string and at preset locations corresponding to the back-contact solar cells in the second battery string. The bent welding strip is turned toward the insulating buffer rubber side by the pressure roller, and the busbar and welding strip are clamped and welded by the welding head and welding support plate.

[0027] Optionally, the terminal busbar is positioned at a preset position corresponding to the back contact cell in the first battery string and at a preset position corresponding to the back contact cell in the second battery string, and further includes: applying an adhesive film to the side of the terminal busbar facing the insulating buffer adhesive and preheating it.

[0028] Optionally, the method further includes: the back contact solar cell is a single screen electrode arrangement, the screen of the back contact solar cell is the same as the printing screen of the insulating buffer adhesive, and multiple back contact solar cells are arranged along the second direction to form a battery string, wherein the back contact solar cell in two adjacent back contact solar cells is rotated 180° relative to the front back contact solar cell.

[0029] Optionally, the arrangement of multiple back-contact battery cells along a second direction to form a battery string further includes: the multiple battery strings forming a first battery string group and a second battery string group, with an intermediate busbar provided between the first battery string group and the second battery string group, and the first battery string group and the second battery string group being arranged symmetrically about the central axis of the intermediate busbar in a first direction.

[0030] Through the above technical solution, by setting the insulating buffer adhesive, the busbar can be separated from the grid lines of different polarities when it is placed on the back side of the battery cell, reducing the risk of short circuit in the battery cell. At the same time, it plays a buffering role during battery string stacking and lamination, reducing the risk of cell cracking.

[0031] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the accompanying drawings...

[0033] Figure 1 This is a schematic diagram of the layout of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0034] Figure 2 This is a first partial enlarged view of the intermediate busbar of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0035] Figure 3 This is a partially enlarged view of the end busbar of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0036] Figure 4 This is a second partial enlarged view of the intermediate busbar of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0037] Figure 5 This is a third enlarged view of the intermediate busbar of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0038] Figure 6 This is a schematic diagram of a back-contact battery cell provided in an exemplary embodiment of this disclosure.

[0039] Figure 7 This is a schematic diagram of a battery string provided in an exemplary embodiment of this disclosure.

[0040] Figure 8 This is an exploded view of a photovoltaic module provided in an exemplary embodiment of this disclosure.

[0041] Figure 9 This is a schematic diagram of a first printed pattern of the insulating buffer adhesive provided in an exemplary embodiment of this disclosure.

[0042] Figure 10 This is a schematic diagram of a second type of printed pattern of the insulating buffer adhesive provided in an exemplary embodiment of this disclosure.

[0043] Figure 11 This is a schematic flowchart of the preparation method provided in an exemplary embodiment of this disclosure.

[0044] Figure 12 This is a partial view of the welding strip drawing equipment in the preparation method provided in the exemplary embodiments of this disclosure.

[0045] Figure 13 This is a schematic diagram of a busbar and welding strip welding method provided in an exemplary embodiment of this disclosure.

[0046] Figure 14 This is a schematic diagram of the welding of the end busbar and the welding strip in the preparation method provided in the exemplary embodiment of this disclosure.

[0047] Figure 15 This is a schematic diagram showing the positional relationship between the intermediate busbar and the welding strip in the preparation method provided in the exemplary embodiment of this disclosure.

[0048] Figure 16 yes Figure 15 A schematic diagram of the cross-section of the intermediate busbar and the solder strip after molding using the Chinese preparation method.

[0049] Figure 17 This is a schematic diagram of another welding method for the intermediate busbar and the welding strip in the preparation method provided in the exemplary embodiment of this disclosure.

[0050] Figure 18 yes Figure 16 A schematic diagram of the welding process between the intermediate busbar and the welding strip.

[0051] Figure 19 This is a schematic diagram of the structure of photovoltaic modules using AB plates in related technologies.

[0052] Figure 20 The structure of photovoltaic modules using AB strings in related technologies is shown in the figure.

[0053] Figure 21 This is a schematic diagram of a photovoltaic module in related technologies.

[0054] Figure 22 yes Figure 21 Enlarged schematic diagram of the middle busbar.

[0055] Explanation of reference numerals in the attached figures 1-Battery string; 11-Back contact battery cell; 2-Welding ribbon; 3-Busbar; 31-End busbar; 32-Intermediate busbar; 4-Insulating buffer adhesive; 5-First battery string group; 6-Second battery string group; 7-Insulating decorative strip; 100-Photovoltaic module; 101-Frame; 102-Backsheet; 103-First encapsulating film; 104-Second encapsulating film; 105-Front glass; 200-Welding ribbon traction; 201-Bending roller; 202-Welding ribbon cutter; 203-Pressure roller; 204-Busbar transporter; 205-Welding head. Detailed Implementation

[0056] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0057] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" refer to the outline of the component itself, and "first direction" can be referred to as... Figure 1 The "X-direction" corresponds to the direction of the long side of the photovoltaic module frame. The "second direction" can be referenced. Figure 1 In the Y-direction, which corresponds to the direction of the short side extension of the photovoltaic module frame, the terms used, such as "first" and "second," are used to distinguish one element from another and do not indicate sequence or importance. Furthermore, in the description referring to the accompanying drawings, the same reference numerals in different drawings denote the same element.

[0058] In related technologies, such as Figures 19 to 22 In back-contact photovoltaic modules, since all electrodes of the back-contact cells 11 are located on the back side, insulating strips are typically used to isolate the busbars from the irregularly shaped solder ribbons to reduce the risk of short circuits. However, the insulating strips require high placement precision; the openings in the insulating strips must be aligned with the solder ribbons 2. Misalignment will cause incomplete soldering, and severe misalignment will lead to short circuits / open circuits in the cells. Furthermore, during aging tests, the insulating strips are more prone to delamination, which can also cause short circuits in the cells.

[0059] To achieve the above objectives, such as Figures 1 to 18 As shown, the first aspect of this disclosure provides a photovoltaic module 100, including: a plurality of cell strings 1, a plurality of busbars 3, and insulating buffer 4, wherein each cell string 1 includes a plurality of back-contact cells 11, and adjacent back-contact cells 11 are connected in series by solder strips 2; the busbars 3 are located on the back surface of the cell strings 1, and the busbars 3 are used to connect at least two cell strings 1; the insulating buffer 4 is disposed between the cell strings 1 and the busbars 3, and is used to insulate and isolate the busbars 3 and the grid lines on the back-contact cells 11 that have a polarity different from that of the busbars 3.

[0060] Through the above technical solution, by setting the insulating buffer adhesive 4, the busbar 3 can be separated from the grid lines of different polarities when it is set on the back side of the back contact solar cell 11, thereby reducing the risk of short circuit of the back contact solar cell 11. At the same time, it plays a buffering role during the stacking and lamination of the solar cell string, thereby reducing the risk of cell cracking.

[0061] It is understandable that, such as Figure 7As shown, the photovoltaic module 100 also includes a frame 101, a backsheet 102, a first encapsulating film 103, a battery string 1, a second encapsulating film 104, and a front glass 105. The stacking sequence before lamination can be as follows: first, place the front glass 105; then, lay the second encapsulating film 104 on the front glass 105; finally, place the pre-fabricated battery string 1 (including solder ribbons 2 and busbars 3) on the second encapsulating film 104; then, place the first encapsulating film 103 and the backsheet. Sealant is also applied to the edges of the front glass 105 and the backsheet 102. After lamination, a laminate is formed, and the laminate is then assembled using the frame to form the photovoltaic module 100. Before lamination, the battery string 1 is a completed, wire-welded assembly, including the connection of all solder ribbons 2 and busbars 3. After the battery string 1 is welded, it is bonded to the front glass 105 and the backsheet 102 using the first and second encapsulating films to form the laminate.

[0062] In this embodiment, the insulating buffer adhesive 4 may include: phenolic epoxy acrylate oligomer, 2-ethylanthraquinone, 1-hydroxycyclohexylphenyl ketone, trimethylolpropane triacrylate, hydroxyethyl methacrylate, talc, silica, bentonite, phthalocyanine green G, and dimethylpolysiloxane. Specifically, the mass fractions of each component are as follows: phenolic epoxy acrylate oligomer can account for 30%~50%, 2-ethylanthraquinone for 1%-3%, 1-hydroxycyclohexylphenyl ketone for 1%~5%, trimethylolpropane triacrylate for 10%~15%, hydroxyethyl methacrylate for 5%~10%, talc for 20%~35%, silica for 0.1%~2%, bentonite for 0.5%~2%, phthalocyanine green G for 0.1%~2%, and dimethylpolysiloxane for 0.5%~2%. Specifically, in some possible embodiments, for example, the proportion of phenolic epoxy acrylate oligomer can be 30%, the proportion of 2-ethylanthraquinone can be 3%, the proportion of 1-hydroxycyclohexylphenyl ketone can be 5%, the proportion of trimethylolpropane triacrylate can be 15%, the proportion of hydroxyethyl methacrylate can be 10%, the proportion of talc can be 35%, the proportion of silica can be 0.5%, the proportion of bentonite can be 0.5%, the proportion of phthalocyanine green G can be 0.5%, and the proportion of dimethicone can be 0.5%. Of course, it is understood that the above-described component proportions of the insulating buffer adhesive 4 are illustrative; in other embodiments, each component can be any value within a preset range, which will not be elaborated further in this disclosure.

[0063] like Figures 1 to 7 As shown, the first direction can be referenced. Figure 1 The X-direction corresponds to the long side extension direction of the frame 101 in the photovoltaic module 100. The second direction can be referenced. Figure 1 In the Y-direction, corresponding to the short side extension direction of the frame 101 in the photovoltaic module 100, the back-contact solar cell 11 can be provided with main grid lines, which extend along the long side. Since the sub-grid lines in the back-contact solar cell 11 are arranged perpendicular to the main grid lines, their extension direction is along the short side. The positive and negative electrodes on the back surface of the back-contact solar cell 11 are arranged in an interdigitated pattern, with adjacent main grid lines corresponding to the positive or negative electrode, respectively. The busbar 3 is arranged perpendicular to the direction of the main grid lines in the back-contact solar cell 11, and extends along the short side of the frame 101. The busbar 3 collects the current from the main grid lines of the same polarity. Multiple battery strings 1 are divided into a first battery string group 5 and a second battery string group 6 along the first direction. The number of battery strings 1 in the first battery string group 5 and the second battery string group 6 is equal, and an intermediate busbar 32 is provided between the first battery string group 5 and the second battery string group 6, and they are connected in parallel through the intermediate busbar 32. For example, each of the first battery string group 5 and the second battery string group 6 has 6 battery strings 1, which extend along a first direction and are spaced apart along a second direction. Adjacent battery strings 1 are connected in series. End busbars 31 are provided on the outer side of the first battery string group 5 and the second battery string group 6 (i.e., on the side away from the intermediate busbar 32). There can be multiple end busbars 31, and there can also be multiple intermediate busbars 32. Figure 1 In the photovoltaic module 100 shown, there are 6 end busbars 31, and 3 of them are respectively set at the outer ends of the first battery string group 5 and the second battery string group 6. There are 4 middle busbars 32, and they are all spaced apart at the inner ends of the first battery string group 5 and the second battery string group 6 (i.e., the ends of the first battery string group 5 and the second battery string group 6 are arranged opposite each other in the first direction). The end busbars 31 and the middle busbars 32 are respectively used to collect the current of the same polarity main grid line in the multiple battery strings 1 in the first battery string group 5 and the second battery string group 6.

[0064] In some possible implementations, to facilitate the collection, transmission, and output of current from the battery string 1, junction boxes can be provided between adjacent intermediate busbars 32 among the four intermediate busbars 32. Through the arrangement of three junction boxes (not shown in the figure), the current generated by the multiple battery strings 1 in the photovoltaic module 100 is led out to the external circuit via the junction boxes. It is understood that the aforementioned junction boxes are existing products, and their specific structures will not be described in detail in this disclosure.

[0065] In some possible implementations, the spacing between adjacent battery strings 1 can be either positive or negative. When the spacing between adjacent battery strings 1 is positive, the back-contact solar cells 11 of the adjacent battery strings 1 do not overlap and maintain a gap. This avoids collision damage to the back-contact solar cells 11 and facilitates welding. When the spacing between adjacent battery strings 1 is negative, the back-contact solar cells 11 of the adjacent battery strings 1 partially overlap, thereby reducing the gap between adjacent back-contact solar cells 11, increasing the power density of the battery pack, and improving power generation efficiency.

[0066] In some possible implementations, the positive spacing between adjacent battery strings 1 is 2mm to 4mm. In this case, the positive spacing between battery strings 1 can be any one of 2mm, 2.1mm, 2.2mm, 2.3mm, 2.5mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, and 4mm. It is understood that the values ​​listed above for positive spacing of battery strings 1 are illustrative, and in other implementations, the positive spacing between battery strings 1 can also be any value between 2mm and 4mm.

[0067] In some possible implementations, the spacing between adjacent battery strings 5 ​​can also be a negative spacing, wherein the negative spacing can be -0.8mm to -1.8mm. In this case, the negative spacing between battery strings 1 can be -0.8mm, -0.9mm, -1mm, -1.2mm, -1.5mm, or -1.8mm. Here, the negative spacing refers to the length of the overlapping area of ​​the back-contact battery cells 11 corresponding to adjacent battery strings 1. It is understood that the values ​​listed above for negative spacing are illustrative; in other implementations, the negative spacing between battery strings 1 can be any value between -0.8mm and -1.8mm.

[0068] In the photovoltaic module 100, in order to facilitate manufacturing and reduce costs, the first battery string group 5 and the second battery string group 6 in the photovoltaic module 100 are arranged on the same plane. The intermediate busbar 32 and the back contact battery cells 11 of the first battery string group 5 and the second battery string group 6 adjacent to the intermediate busbar 32 are provided with insulating buffer adhesive 4. That is, the intermediate busbar 32 occupies part of the back light surface area of ​​the back contact battery cells 11 in the first battery string group 5 and part of the back light surface area of ​​the back contact battery cells 11 in the second battery string group 6. The top surface of the intermediate busbar 32 (the side away from the corresponding back contact battery cell 11) is connected to the first battery string group 5 and the second battery string group 6 respectively by solder ribbon 2. Thus, the first battery string group 5 and the second battery string group 6 can be connected in parallel through the intermediate busbar 32.

[0069] Of course, when the intermediate busbar 32 occupies part of the back-light area of ​​the back-contact solar cell 11 in the first and second battery string groups 5 and 6, there will be gaps on the front of the photovoltaic module 100, which will damage the overall aesthetics. In this case, an insulating decorative strip can be set at the intermediate busbar 32. The insulating decorative strip can completely cover the intermediate busbar 32, thereby shielding the intermediate busbar 32 and making the metal part invisible from the front, so that the surface color of the photovoltaic module is consistent and meets the appearance requirements of the photovoltaic module.

[0070] For example, the aforementioned insulating decorative strip 7 is mostly made of high-polymer elastic materials with strong weather resistance, including EPDM rubber (ethylene propylene diene monomer rubber). By setting the insulating decorative strip 7 as EPDM rubber, the insulating decorative strip 7 can have excellent high and low temperature resistance, UV aging resistance, good elasticity, and is not easy to crack after long-term use.

[0071] The first battery string group 5 and the second battery string group 6 connected to the intermediate busbar 32 are arranged with a positive spacing. In other feasible embodiments, the first battery string group 5 and the second battery string group 6 connected to the intermediate busbar 32 can also be arranged with a negative spacing. That is, the first battery string group 5 and the second battery string group 6 have an overlapping area in the first direction. Of course, in order to avoid short circuits between the first battery string group 5 and the second battery string group 6, insulating buffer adhesive 4 needs to be provided in the overlapping area of ​​the first battery string group 5 and the second battery string group 6.

[0072] To improve the performance and reliability of the photovoltaic module 100, specifically to meet the requirements for thermal stress relief and electrification performance optimization in the photovoltaic module 100, such as... Figure 1 and Figure 2 As shown, the first battery string group 5 and the second battery string group 6 can be on the same plane. The position of the intermediate busbar 32 is slightly higher than the back contact battery cell 11 in the adjacent first battery string group 5 and second battery string group 6. After the intermediate busbar 32 is cut, an insulating decorative strip is hot-stamped on the non-welding surface, and then it is transported to the preset position. After the battery string 1 is picked up, since the welding strips 2 at both ends of the battery string 1 are bent, the battery strings 1 on both sides of the intermediate busbar 32 are directly aligned with the preset position. The intermediate busbar 32 is inserted into the angle area formed by the two battery strings 1 and then directly welded, thereby completing the welding of the intermediate busbar 32 with the first battery string group 5 and the second battery string group 6.

[0073] In addition to the above-described structure, the first battery string group 5 and the second battery string group 6 can also be arranged in a staggered manner with the intermediate busbar 32. For example, the first battery string group 5 is positioned higher than the second battery string group 6. In this case, to completely hide the intermediate busbar 32, the intermediate busbar 32 is positioned above the back contact battery cell 11 corresponding to the first battery string group 5. The multiple back contact battery cells 11 in the first battery string group 5 are connected by string welding. After the battery string 1 is formed, an extended solder strip 2 is reserved to cooperate with the intermediate busbar 32. At this time, the extended solder strip 2 is bent and welded to the intermediate busbar 32, and an insulating buffer adhesive 4 is placed between the solder strip 2 and the back contact battery cell 11. After multiple back contact battery cells 11 in the second battery string group 6 are connected in series to form battery string 1, an extended solder strip 2 is also reserved to cooperate with the intermediate busbar 32. At this time, the extended solder strip 2 located in the second battery string group 6 is bent and welded to the side of the intermediate busbar 32 away from the insulating buffer adhesive 4. In this way, the first battery string group 5 and the second battery string group 6 can be connected in parallel through the intermediate busbar 32, and the intermediate busbar 32 can also be placed on the back side of the back contact battery cell 11 in the corresponding battery string 1 in the first battery string group 5. This not only increases the light-receiving area of ​​the photovoltaic module and improves power generation efficiency, but also allows the middle busbar 32 to be completely blocked by the back-contact solar cell 11, meeting the appearance requirements of the photovoltaic module 100.

[0074] It is understood that the position of the first battery string group 5 above the second battery string group 6 is illustrative. In other embodiments, the position of the first battery string group 5 may also be lower than the second battery string group 6. In this case, the insulating buffer adhesive 4 is placed on the back-light side of the back-contact battery cell 11 in the corresponding battery string 1 in the second battery string group 6, and the intermediate busbar 32 is located on the back-light side of the back-contact battery cell 11 in the battery string 1. After the battery string 1 in the second battery string group 6 is wire-welded, a solder strip 2 is reserved for welding to the intermediate busbar 32. The solder ribbon 2 is located above the insulating buffer adhesive 4, and the solder ribbon 2 is directly welded to the intermediate busbar 32. After the back contact solar cells 11 corresponding to the first battery string group 5 are connected in series, they will form an extended solder ribbon 2. At this time, the solder ribbon 2 in the first battery string group 5 is welded to the side of the intermediate busbar 32 away from the insulating buffer adhesive 4, so that the first battery string group 5 and the second battery string group 6 can be connected in parallel through the intermediate busbar 32, and the intermediate busbar 32 is shielded by the back contact solar cells 11 in the second battery string group 6 to meet the appearance requirements of the photovoltaic module 100.

[0075] In order to allow the end busbar 31 to also be hidden on the backlight side of the back contact battery cell 11, in some possible embodiments, such as Figures 1 to 3As shown, there are multiple end busbars 31. End busbars 31 are provided on the side away from the middle busbar 32 in the first battery string group 5 and the second battery string group 6. The end busbars 31 extend along the long side of the photovoltaic module 100. An insulating buffer 4 is provided between the back contact cells 11 adjacent to the end busbars 31 in the first battery string group 5 and the second battery string group 6. At this time, the end busbars 31 are placed on the insulating buffer 4. After the back contact cells 11 in the battery string 1 of the first battery string group 5 are wired, a solder strip 2 is reserved. The reserved solder strip 2 is welded to the end busbar 31. Similarly, after the back contact cells 11 in the battery string 1 of the second battery string group 6 are wired, a solder strip 2 is reserved. The reserved solder strip 2 is welded to the corresponding end busbar 31. Thus, by providing end busbars 31 on the side away from the intermediate busbar 32 in both the first battery string 5 and the second battery string 6, the same polarity solder strips 2 in the first battery string group 5 and the second battery string group 6 can be welded to the corresponding end busbars 31 to draw out the current. By setting the end busbars 31 on the back surface of the corresponding back contact cell 11, the light-receiving area can be increased, and the power generation efficiency of the photovoltaic module 100 can be improved. In addition, by setting the insulating buffer adhesive 4 at a preset position on the back surface of the back contact cell 11, when the end busbars 31 are set at the preset position, the back surface of the corresponding back contact cell 11 can shield the end busbars 31, so that the end busbars 31 are completely hidden on the back surface of the back contact cell 11, thereby meeting the appearance requirements of the photovoltaic module 100.

[0076] In some possible implementations, the distance between the edge of the busbar 3 and the edge of the insulating buffer 4 is not less than 2 mm. For example, the busbar 3 includes an end busbar 31 and an intermediate busbar 32. The distance between the edge of the end busbar 31 and the edge of the intermediate busbar 32 and the edge of the insulating buffer 4 is not less than 2 mm, which means that the minimum distance from the outer contour of the end busbar 31 and the intermediate busbar 32 to the outer contour of the insulating buffer 4 is not less than 2 mm. In order to avoid the risk of leakage and partial short circuit, the end busbar 31 is required to have an edge distance from the edge of the back contact battery cell 11 of not less than 1 mm. The insulating buffer 4 is provided between the end busbar 31 and the back contact battery cell 11. In order to meet the insulation requirements of the end busbar 31, in this embodiment, the minimum distance from the outer contour of the end busbar 31 to the outer contour of the insulating buffer 4 is not less than 2 mm. The outer end of the insulating buffer 4 that mates with the end busbar 31 is aligned with the edge of the corresponding back contact battery cell 11. In some possible implementations, in order to prevent the busbar 3 from being misaligned or splattered, which could cause a short circuit due to the connection of the different grid lines of the back contact battery cell 11, the width of the insulating buffer 4 is required to be greater than 8 mm. The width of the insulating buffer 4 refers to the extension of the edge of the insulating buffer 4 that overlaps with the back contact battery cell 11 toward the inside of the back contact battery cell 11. Here, the specific value of the width of the insulating buffer 4 is determined according to the specifications of the end busbar 31.

[0077] The edge of the insulating buffer 4 that cooperates with the intermediate busbar 32 is not less than 2mm away from the edge of the intermediate busbar 32. That is, the insulating buffer 4 is provided on one side edge of the two adjacent back contact battery cells 11 that cooperate with the intermediate busbar 32, which is close to the edge of the intermediate busbar 32. The outer edge of the insulating buffer 4 coincides with the outer edge of the corresponding back contact battery cell 11. The insulating buffer 4 extends from the outer edge of the corresponding back contact battery cell 11 toward the inward. The specific value of the width of the insulating buffer 4 is determined according to the specifications of the intermediate busbar 32.

[0078] Of course, the busbar 3 is divided into end busbar 31 and intermediate busbar 32. The minimum width of the intermediate busbar 32 needs to be greater than or equal to 3.5mm to carry a current of 20A-30A without overheating. In order to balance the current carrying capacity and the welding process, in this embodiment, the width of the intermediate busbar 32 is approximately 9mm to 11mm. The end busbar 31 needs to carry the current of 1 to 3 battery strings (3A-8A). In order to balance the current carrying capacity and the welding process, the width of the end busbar 31 is approximately 4mm to 5mm. At this time, the width range of the insulating buffer adhesive 4 corresponding to the end busbar 31 and the width range of the insulating buffer adhesive 4 corresponding to the intermediate busbar 32 both need to be greater than 8mm.

[0079] In some possible implementations, the thickness of the insulating buffer adhesive 4 is D, where 40μm ≥ D ≥ 30μm. It should be noted that if the insulating buffer adhesive 4 is too thin, it risks being punctured by the solder ribbon 2, easily leading to a short circuit. The thickness of the insulating buffer adhesive 4 is positively correlated with structural strength; furthermore, increasing the thickness leads to increased adhesive usage and cost. Therefore, by controlling the thickness of the insulating buffer adhesive 4 between 30μm and 40μm, it can effectively isolate the electrodes while meeting structural strength requirements and cost control requirements.

[0080] In related technologies, such as Figures 19 to 22 As shown, in photovoltaic modules 100 using back-contact solar cells 11, different solar cell grids are typically used, i.e., two different back-contact solar cells 11 are used. One type of back-contact solar cell 11 starts with the positive terminal, while the other type starts with the negative terminal. The distribution diagram of the cells after they are welded into strings is shown below. Figure 19 As shown, its layout is as follows Figure 20 As shown, the photovoltaic module 100 thus consists of two types of cell strings, which can be referred to for details. Figure 20 The arrangement of strings A and B results in the solder strips in the middle position needing to overlap with the middle busbar 32 with staggered teeth (the staggered tooth width is 0~2mm). At this time, the layout of the first battery string group 5 and the second battery string group 6 is not strictly symmetrical with respect to the middle busbar 32, and is misaligned by 0~2mm, which causes the creepage distance of the long side of the photovoltaic module 100 to be unevenly distributed. In addition, due to the distribution of strings A and B, the stacking logic of the welding machine becomes complicated, the storage and layout design of battery string 1 becomes complicated, and the replacement of defective battery cells may also be complicated.

[0081] In this disclosure, to facilitate the string soldering of battery strings, such as Figure 5 and Figure 6 As shown, the back-contact solar cells 11 in the battery string 1 are arranged with a single screen electrode. The screen for the back-contact solar cells 11 is the same as the printing screen for the insulating buffer adhesive 4. By setting the back-contact solar cells 11 as a single screen electrode arrangement, it is easier to arrange multiple back-contact solar cells 11 in the battery string 1. During the stringing process, by rotating adjacent back-contact solar cells 11 by 180° to form a single string, the positive and negative electrodes can be reversed simply by rotating the direction of the string during the arrangement process. Figure 6 As shown, when the battery string 1 is arranged, multiple back-contact battery cells 11 are arranged along the first direction. The first cell starts with the positive electrode, then the second cell rotates and starts with the negative electrode, and so on. The electrode distribution after the multiple back-contact battery cells 11 are welded into a string is as follows. Figure 6 As shown, the layout is as follows: Figure 1As shown, since the A and B strings are no longer distinguished after string welding, a large misalignment is naturally formed at the welding position of the middle busbar 32. The two battery strings on both sides of the middle busbar 32 are symmetrical about the central axis of the middle busbar 32, thus the creepage distance on the long side is evenly distributed, further improving the safety of the photovoltaic module.

[0082] Of course, eliminating the time-consuming AB string switching in related technologies, i.e., when welding AB strings in related technologies, enables rapid switching of battery strings, reduces operational logic, and improves production efficiency.

[0083] like Figures 1 to 22 As shown, the second aspect of this disclosure provides a method for preparing a photovoltaic module, the method comprising: S1. Provide multiple battery strings 1, each battery string 1 including multiple back contact battery cells connected in series via solder strips 2. S2. Provide insulating buffer adhesive 4, and place the insulating buffer adhesive 4 at a preset position in the battery string 1 that is in contact with the battery cell 11. S3. Provide multiple busbars 3, which are set at preset positions on the back contact battery cell 11 and are welded to the adjacent battery string 1. S4. The welded battery string 1 and busbar 3 are laminated and encapsulated to form a photovoltaic module 100.

[0084] Through the above technical solution, the back-contact solar cells 11 within multiple cell strings 1 in the photovoltaic module 100 absorb light and generate electricity. Multiple busbars 3 are positioned at predetermined locations on the back-contact solar cells 11, and insulating buffer adhesive 4 is applied at these predetermined locations. This effectively insulates and isolates the busbars 3 from the dissimilar electrode grid lines on the back-contact solar cells 11. After lamination and encapsulation, the photovoltaic module 100 is manufactured. Thus, the insulating buffer adhesive 4 in this photovoltaic module 100 insulates and isolates the busbars 3 from the dissimilar electrode grid lines on the back-contact solar cells 11. By placing the busbars 3 on the back-light-receiving surface of the back-contact solar cells 11, the busbars 3 are also completely shaded, reducing the blank space caused by the busbars 3 in the photovoltaic module 100, increasing the light-receiving area of ​​the photovoltaic module 100, and improving the luminous efficiency of the photovoltaic module 100.

[0085] It is understandable that a photovoltaic module 100 includes a long side and a short side, where the long side can be referenced. Figure 1 The first direction X in the middle, the short side can be referenced Figure 1In the second direction Y, since the back-contact solar cell 11 can be provided with main grid lines, which extend along the long side, the busbar 3 is set perpendicular to the direction of the main grid lines in the back-contact solar cell 11. At this time, the busbar 3 is located on the short side extension, and the busbar 3 collects the current of the main grid lines of the same polarity. The busbar 3 includes an end busbar 31 and an intermediate busbar 32. Multiple battery strings 1 are divided into a first battery string group 5 and a second battery string group 6 along the first direction. The number of battery strings 1 in the first battery string group 5 and the second battery string group 6 is equal. An intermediate busbar 32 is provided between the first battery string group 5 and the second battery string group 6, and they are connected in parallel through the intermediate busbar 32. An end busbar 31 is provided on the side of the first battery string group 5 and the second battery string group 6 away from the intermediate busbar 32, respectively. The end busbar 31 is provided to draw out the current of the battery strings 1 of the same polarity in the battery strings 1.

[0086] Of course, such as Figure 11 As shown, after the back contact solar cells 11 are placed in a preset direction and position, multiple welding strips 2 are pulled out by the welding strip traction 200 and overlapped on the multiple back contact solar cells 11. The extended welding strips 2 located at the end of the solar cell and cooperating with the busbar are bent by the setting of the bending roller 201. The welding strips are cut into preset lengths by the welding strip cutter.

[0087] In S2, the method further includes: an insulating buffer adhesive 4 is provided between the intermediate busbar 32 and the back contact battery cell 11 of the first battery string group 5 and / or the second battery string group 6 adjacent to the intermediate busbar 32.

[0088] The insulating buffer adhesive 4 is applied to a predetermined position on the back contact battery cell 11 by printing, such as... Figure 9 and Figure 10 As shown, the preset position can be one side of the long side of the back contact battery cell 11. That is, insulating buffer adhesive 4 is provided on the edge of the long side of the back contact battery cell 11 at both ends of the first battery string group 5 and the second battery string group 6, so that the first battery string group 5 and the second battery string group 6 can be connected to the corresponding end busbar 31 and the middle busbar 32.

[0089] Of course, the above-described structure of providing insulating buffer adhesive 4 along the long edges of the back contact battery cells 11 at both ends of the first battery string group 5 and the second battery string group 6 is illustrative. In other embodiments, insulating buffer adhesive 4 is provided at a predetermined position for each back contact battery cell 11, that is, insulating buffer adhesive 4 is provided along the edges of the two long edges of each back contact battery cell 11. Thus, by providing insulating buffer adhesive 4 at a predetermined position for each back contact battery cell 11, the feeding logic of the back contact battery cells 11 can be simplified, and it is also convenient to replace any defective back contact battery cells 11.

[0090] In some possible implementations, the spacing between the corresponding two battery strings 1 connected to the intermediate busbar 32 can be a positive spacing. The multiple back-contact battery cells 11 in the multiple battery strings 1 in the first battery string group 5 and the second battery string group 6 are arranged in a first direction and wired together by a wire welding machine. After wire welding, a corresponding wire welding strip 2 is reserved in the extension direction of the wire welding strip 2 in the battery string 1 so that the reserved wire welding strip 2 can be welded to the end busbar 31 or the intermediate busbar 32. The intermediate busbar 32 is positioned between the first battery string group 5 and the second battery string group 6. The reserved welding strips 2 in the first battery string group 5 and the second battery string group 6 are bent in the direction away from the back contact battery cell 11. The bending of the welding strip 2 can form a positioning guide at the end of the welding strip 2, improve the alignment accuracy of welding with the intermediate busbar 32, reduce the number of false welds, and balance stress release and space occupation. The busbar transporter 204 places the intermediate busbar 32 in the area enclosed by the corresponding back contact battery cell 11 in the first battery string group 5, the corresponding back contact battery cell 11 in the second battery string group 6, and the welding strip 2. The welding head 205 presses and welds the intermediate busbar 32 and the corresponding back contact battery cell 11.

[0091] In some possible implementations, in step S2, an insulating decorative strip is also provided between the intermediate busbar 32 and the insulating buffer adhesive 4. When the intermediate busbar 32 occupies part of the back-light surface area of ​​the back-contact solar cell 11 in the first and second cell string groups 5 and 6, the insulating decorative strip can also play an insulating buffering role, preventing damage to the overall aesthetics. In addition, the insulating decorative strip 7 can completely cover the intermediate busbar 32, thereby shielding the intermediate busbar 32 and making the metal part invisible from the front, so that the surface color of the photovoltaic module is uniform and meets the appearance requirements of the photovoltaic module.

[0092] In step S3, the method further includes: the bending angle of the lead-out solder strip is less than 45°, where the bending angle is the angle between the solder strip and the backlight surface of the solar cell. A bending angle of less than 45° can form a micro-arched structure, providing 2mm-3mm of expansion space, reducing stress below the critical fracture strength of the silicon wafer. The end of the solder strip with a bending angle of less than 45° forms a wedge-shaped guide surface, which cooperates with the buffer layer of the intermediate busbar 32 to achieve precise docking. When the battery string 1 moves in parallel, the bent solder strip 2 automatically slides into the preset position of the intermediate busbar 32, reducing the positioning error of the robot arm. In addition, the insulating buffer adhesive 4 can fit the wedge-shaped angle of the bent solder strip 2 to achieve surface contact and improve the welding yield.

[0093] Of course, it is understood that the bending angle of the welding strip mentioned above, which is less than 45°, is illustrative. In other embodiments, the bending angle can be selected according to the working conditions. This disclosure does not make any specific limitation.

[0094] In step S3, such as Figures 16 to 18 As shown, the spacing between multiple battery strings 1 is negative. The lead-out welding strips 2 in the first battery string group 5 and the second battery string group 6 are bent in the direction away from the back contact battery cell 11. The intermediate busbar 32 is vertically arranged between the first battery string group 5 and the second battery string group 6, and the lowest point of the intermediate busbar 32 is higher than the back contact battery cell 11 by a first preset distance. The welding head 205 welds the vertical intermediate busbar 32 and the corresponding welding strip 2. After welding, the pressure roller 203 is used to tilt the welded intermediate busbar 32 toward the side where the insulating buffer adhesive 4 is set. Specifically, to improve the performance and reliability of the photovoltaic module 100, i.e., to meet the requirements of thermal stress release and electrification performance optimization in the photovoltaic module 100, the first battery string group 5 and the second battery string group 6 are arranged in a staggered manner. For example, the position of the first battery string group 5 is lower than that of the second battery string group 6, and the spacing between multiple battery strings 1 is a negative spacing, which can be -0.8mm to -1.8mm. This further reduces the blank area in the photovoltaic module 100 and improves the power generation efficiency. Due to the staggered arrangement of the first battery string group 5 and the second battery string group 6, the intermediate busbar 32 is welded to the outer solder strip 2 of the first battery string group 5 and the outer solder strip 2 of the second battery string group 6. Afterwards, the welded intermediate busbar 32 needs to be tilted towards the back contact cell 11 with insulating buffer adhesive 4 by the pressure roller 203 to cover the intermediate busbar 32. At this time, in order to adapt to the flattening process of the pressure roller, the lowest point of the intermediate busbar 32 is higher than the back contact cell 11 in the higher second battery string 6 by a first preset distance. By setting the first preset distance, the requirements for heat stress release can be met. At the same time, there is enough room for shrinkage when the weld joint cools down during welding. In addition, the raising of the intermediate busbar 32 directly increases the insulation distance with the edge of the back contact cell 11 in the second battery string 6, preventing the risk of short circuit caused by the displacement of the intermediate busbar 32 due to vibration and thermal expansion and contraction. In some possible embodiments, the first preset distance may not be greater than 2mm. In addition, in order to facilitate the welding of the intermediate busbar 32 with the lead-out welding strips 2 on both sides in a vertical state, the bending angle of the lead-out welding strips is greater than 80°, where the bending angle is the angle between the welding strip and the back surface of the battery cell. Thus, by setting the bending angle of the lead-out solder strip 2 to be greater than 80°, for example, between 80° and 85°, with a 1° fine adjustment for back contact battery cells 11 of different thicknesses and solder strips of different materials, the lead-out solder strip 2 can be made approximately parallel to the busbar 32, maximizing the contact area between the solder strip 2 and the intermediate busbar 32, making it easier to weld the solder strip 2 and the intermediate busbar 32.

[0095] It is understood that the bending angle of the welding strip 2 above is set to be greater than 80° as illustrative. In other embodiments, it can be selected according to the specific working conditions. For example, the bending angle of the welding strip 2 above can also be other angles.

[0096] In some possible implementations, step S3 further includes: an end busbar 31 is disposed on the backlight surface of the first battery string group 5 and the second battery string group 6 on the side away from the intermediate busbar 32, and an insulating buffer adhesive 4 is provided between the end busbar 31 and the back-contact solar cell 11 of the first battery string group 5 and the second battery string group 6 adjacent to the end busbar 31. For example, by providing end busbars 31 on the backlight surface of the first battery string group 5 and the second battery string group 6 on the side away from the intermediate busbar 32, it is possible to facilitate the collection and discharge of current on the solder strip 2 of the same electrode in the first battery string group 5 and the second battery string group 6. By providing insulating buffer adhesive 4 at the preset position of the end busbar 31 of the corresponding back-contact solar cell 11 in the first battery string group 5 and the second battery string group 6, the end busbar 31 can be hidden on the backlight side of the corresponding back-contact solar cell 11, thereby increasing the light-receiving area of ​​the photovoltaic module 100, improving the power generation efficiency, and also meeting the appearance requirements of the photovoltaic module 100.

[0097] In some possible implementations, in step S3, such as Figure 12 As shown, the method further includes: bending the lead-out solder strips 2 in the first battery string group 5 and the second battery string group 6 towards the direction away from the back contact battery cell 11; setting the end busbar 31 parallel to the bending direction of the corresponding solder strips 2 in the first battery string group 5 and the second battery string group 6; welding the inclined end busbar 31 and solder strips 2 with a welding head; and using a pressure roller to turn the welded end busbar 31 toward the side of the back contact battery cell 11 where the insulating buffer adhesive 4 is provided. The inclined angle of the welding of the inclined end busbar 31 and solder strips 2 allows the connection surface of the solder strip 2 and the end busbar 31 to form a wedge-shaped elastic structure. During welding cooling, the shrinkage stress can be absorbed through small deformations. Simultaneously, it can also increase the contact area between the solder strip 2 and the end busbar 31, improving the reliability of the welding. After welding, the end busbar 31 is turned by the pressure roller toward the side of the back contact solar cell 11 where the insulating buffer 4 is provided, and the end busbar 31 is placed at the preset position of the busbar 3 on the back contact solar cell 11, that is, in contact with the insulating buffer 4. This allows the end busbar 31 to be hidden in the back contact solar cell 11, thereby increasing the light-receiving area of ​​the photovoltaic module 100 and improving the power generation efficiency.

[0098] Of course, the above-mentioned inclined welding method used for the end busbar 31 and the welding strip 2 is illustrative. In other embodiments, in step S3, such as Figure 11As shown, the lead-out solder strips 2 in the first battery string group 5 and the second battery string group 6 are bent in the direction away from the back contact battery cell 11; the end busbar 31 is set at a preset position corresponding to the back contact battery cell 11 in the first battery string group 5 and at a preset position corresponding to the back contact battery cell 11 in the second battery string group 6. The bent solder strip 2 is turned towards the side of the insulating buffer 4 by the pressure roller, and the end busbar 31 and the solder strip 2 are clamped and welded by the welding head and the welding support plate. That is, the end busbar 31 can also be set at a preset position in the corresponding back contact battery cell 11 first, that is, it is first attached to the insulating buffer 4, and then the bent solder strip 2 is turned towards the end busbar 31 by the pressure roller, and the end busbar 31 and the solder strip 2 are clamped and welded by the welding head and the welding support plate.

[0099] Understandably, in order to more accurately install the end busbar 31, an adhesive film can be applied and preheated on the side of the end busbar 31 facing the insulating buffer adhesive 4. This allows the end busbar 31 to be installed more accurately at the preset position of the corresponding back contact battery cell 11.

[0100] In step S1, the electrode mesh of adjacent back-contact battery cells 11 in the battery string 1 is identical. Multiple back-contact battery cells 11 are arranged along a second direction to form the battery string 1. In two adjacent back-contact battery cells 11, the rear battery cell is rotated 180° relative to the front battery cell. Here, the front-rear direction refers to the extension direction of the battery string 1. Figure 1 , Figure 5 and Figure 6 As shown, by setting the back-contact solar cells 11 as the same screen electrode, it is convenient to arrange multiple back-contact solar cells 11 in the battery string 1. During the stringing process, by rotating adjacent back-contact solar cells 11 by 180° to form a single string, the positive and negative electrodes can be interchanged by simply rotating the direction of the string during the arrangement process. Figure 6 As shown, when the battery string 1 is arranged, multiple back-contact battery cells 11 are arranged along the first direction. The first cell starts with the positive electrode, then the second cell rotates and starts with the negative electrode, and so on. The electrode distribution after the multiple back-contact battery cells 11 are welded into a string is as follows. Figure 6 As shown, the layout is as follows: Figure 1 As shown. Since the A and B strings are no longer distinguished after string welding, a large misalignment is naturally formed at the welding position of the middle busbar 32. The two battery strings on both sides of the middle busbar 32 are arranged symmetrically about the central axis of the middle busbar 32, so the creepage distance on the long side is evenly distributed, further improving the safety of the photovoltaic module.

[0101] In step S4, it is understandable that, as Figure 7As shown, the photovoltaic module 100 also includes a frame 101, a backsheet 102, a first encapsulating film 103, a battery string 1, a second encapsulating film 104, and a front glass 105. The stacking sequence before lamination can be as follows: first, place the front glass 105; then, lay the second encapsulating film 104 on the front glass 105; finally, place the pre-fabricated battery string 1 (including solder ribbons 2 and busbars 3) on the second encapsulating film 104; then, place the first encapsulating film 103 and the backsheet 102. Sealant is also applied to the edges of the front glass 105 and the backsheet 102. After lamination, a laminate is formed, and the laminate is then assembled using the frame to form the photovoltaic module 100. Before lamination, the battery string 1 is a completed, wire-welded assembly, including the connection of all solder ribbons 2 and busbars 3. After the battery string 1 is welded, it is bonded to the front glass 105 and the backsheet 102 using the first and second encapsulating films to form the laminate.

[0102] Specifically, specific embodiments of the photovoltaic module manufacturing method in this disclosure are shown below.

[0103] In step S1, insulating buffer adhesive 4 is printed at preset positions on the back surface of the back contact cell 11 in the battery string 1. For example, a screen printing machine can be used to print the insulating buffer adhesive 4 onto the preset soldering positions of the fine grid lines and busbars 3 on the back surface of the back contact cell 11. The insulating buffer adhesive 4 is cured in a UV curing zone / thermosetting chain oven and then transferred to the solder paste printing zone. Solder paste printing on the back of the back contact cell 11: Solder paste is printed onto the back main grid solder joints of the back contact cell 11 using a screen printing machine, then cured in a thermosetting chain oven and transferred to the non-destructive dicing zone. A non-destructive dicing machine is used to dice the cells and arrange the back contact cells 11 in a string. Solder ribbon 2. After stretching to the set length, the strip is cut. The handling robot places the welding strip 2 onto the back contact solar cell 11 for welding, thereby forming the solar cell string 1. According to the set position, the robot places the solar cell string 1 onto the second encapsulation film 104. The end busbars 31 on both sides are cut to the set length and then transported to the set position by the contact welding robot for welding to complete the stacking welding. The middle busbar 32 is first cut to the set length and then placed on the insulating decorative strip for spot heating and fixation. Then the whole assembly is transported to the welding position for welding. The first encapsulation film 103 is covered on the welded solar cell string. The back panel 102 and the front glass 105 are laminated. After the edge sealing tape is fixed, the laminate is formed to produce the photovoltaic module 100.

[0104] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0105] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0106] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A photovoltaic module, characterized in that, include: Multiple battery strings, each battery string comprising multiple back-contact solar cells, adjacent back-contact solar cells being connected in series via solder strips; Multiple busbars are located on the backlight side of the battery strings and are used to connect at least two of the battery strings; and An insulating buffer adhesive is disposed between the battery string and the busbar to insulate and isolate the busbar and the grid lines on the back-contact battery cell that have a polarity opposite to that of the busbar.

2. The photovoltaic module according to claim 1, characterized in that, The busbar includes an end busbar and a middle busbar. Along a first direction, the multiple battery strings are divided into a first battery string group and a second battery string group. The multiple battery strings in the first battery string group and the second battery string group are connected in series, and the first battery string group and the second battery string group are connected in parallel through the middle busbar.

3. The photovoltaic module according to claim 2, characterized in that, The insulating buffer adhesive is provided between the intermediate busbar and the back-contact battery cell in the first battery string group and / or the second battery string group that is adjacent to the intermediate busbar.

4. The photovoltaic module according to claim 3, characterized in that, Each of the back-contact battery cells is provided with insulating buffer adhesive at a predetermined position.

5. The photovoltaic module according to claim 3, characterized in that, An insulating decorative strip is also provided between the intermediate busbar and the insulating buffer adhesive.

6. The photovoltaic module according to claim 3, characterized in that, The solder strip in the first battery string group that connects to the intermediate busbar is located above the solder strip in the second battery string group that connects to the intermediate busbar. The intermediate busbar is located on the back-light surface of the back-contact battery cell closest to the intermediate busbar in the second battery string group. The solder strip in the second battery string group is connected to the bottom surface of the intermediate busbar. The solder strip in the first battery string group is bent and connected to the top surface of the intermediate busbar. The insulating buffer adhesive is disposed between the solder strip in the second battery string group that connects to the intermediate busbar and the back-contact battery cell closest to the intermediate busbar.

7. The photovoltaic module according to claim 3, characterized in that, The first battery string group and the second battery string group are on the same plane. The solder strips in the first battery string group that are connected to the intermediate busbar and the solder strips in the second battery string group that are connected to the intermediate busbar are respectively connected to the top surface of the intermediate busbar. The insulating buffer adhesive is disposed on the bottom surface of the intermediate busbar and between the back contact battery cells disposed adjacent to the intermediate busbar.

8. The photovoltaic module according to claim 2, characterized in that, The end busbar is located on the backlight side of the first battery string group and the second battery string group away from the middle busbar. The end busbar and the back contact battery cells of the first battery string group and the second battery string group adjacent to the end busbar are provided with the insulating buffer adhesive.

9. The photovoltaic module according to claim 1, characterized in that, The distance between the edge of the busbar and the edge of the insulating buffer is not less than 2mm.

10. The photovoltaic module according to claim 1, characterized in that, The thickness of the insulating buffer adhesive is D, where 40μm ≥ D ≥ 30μm.

11. The photovoltaic module according to claim 2, characterized in that, The spacing between adjacent battery strings connected to the intermediate busbar can be either positive or negative.

12. The photovoltaic module according to claim 11, characterized in that, The positive spacing between two adjacent battery strings connected to the intermediate busbar is 2mm~4mm, or The negative spacing between two adjacent battery strings connected to the intermediate busbar is -0.8mm to -1.8mm.

13. The photovoltaic module according to claim 1, characterized in that, The back-contact solar cells in the battery string are arranged with a single screen electrode, and the screen for the back-contact solar cells is the same as the screen for the insulating buffer adhesive.

14. A method for preparing a photovoltaic module, characterized in that, The method includes: Multiple battery strings are provided, each battery string comprising multiple back-contact cells connected in series via solder strips. Provide insulating buffer adhesive, which is placed at a predetermined position in the battery string that contacts the battery cells on the back. Multiple busbars are provided, which are positioned at predetermined locations on the back contact battery and welded to adjacent battery strings. The welded battery strings and busbars are laminated and encapsulated to form photovoltaic modules.

15. The method for preparing a photovoltaic module according to claim 14, characterized in that, The method of placing the insulating buffer adhesive at a predetermined position on the back contact cell of the battery string also includes: the insulating buffer adhesive being placed at the predetermined position on the back contact cell by printing.

16. The method for preparing a photovoltaic module according to claim 14, characterized in that, The busbar includes an end busbar and a middle busbar. Along the first direction, multiple battery strings are divided into a first battery string group and a second battery string group. Multiple battery strings in the first battery string group and the second battery string group are connected in series, and the first battery string group and the second battery string group are connected in parallel through the middle busbar. The provision of multiple busbars, wherein the busbars are positioned at predetermined locations on the back contact cells, further includes: an insulating buffer adhesive is provided between the intermediate busbar and the cells in the first and / or second battery string groups that are adjacent to the intermediate busbar.

17. The method for preparing a photovoltaic module according to claim 16, characterized in that, The method further includes: the spacing between the two battery strings connected to the intermediate busbar is a positive spacing; the lead-out solder strips in the first battery string group and the second battery string group are bent in the direction away from the back contact battery cell; the intermediate busbar is placed in the area enclosed by the corresponding back contact battery cell in the first battery string group, the corresponding back contact battery cell in the second battery string group, and the solder strip; and the welding head presses and welds the composite of the intermediate busbar and the battery cell.

18. The method for preparing a photovoltaic module according to claim 17, characterized in that, The method further includes: an insulating decorative strip is provided between the intermediate busbar and the insulating buffer adhesive.

19. The method for preparing a photovoltaic module according to claim 16, characterized in that, The method further includes: the spacing between the two battery strings connected to the intermediate busbar is a negative spacing. The lead-out solder strips in the first and second battery string groups are bent in the direction away from the back-contact battery cells. The intermediate busbar is vertically positioned between the first and second battery string groups, with the lowest point of the intermediate busbar being a first preset distance higher than the back contact battery cell at the higher position. The welding head welds the vertical intermediate busbar and the corresponding welding strip. After welding, the pressure roller is used to tilt the welded intermediate busbar toward the back contact battery cell on the side where the insulating buffer adhesive is applied.

20. The method for preparing a photovoltaic module according to claim 19, characterized in that, The method further includes: a first preset distance greater than 2mm, and / or The bending angle of the lead-out solder strip is greater than 80°, where the bending angle is the angle between the solder strip and the back surface of the back contact solar cell.

21. The method for preparing a photovoltaic module according to claim 15, characterized in that, The method further includes: an end busbar is disposed on the backlight side of the first battery string group and the second battery string group away from the intermediate busbar, and an insulating buffer is provided between the end busbar and the back contact battery cells of the first battery string group and the second battery string group adjacent to the end busbar.

22. The method for preparing a photovoltaic module according to claim 21, characterized in that, The method further includes: bending the lead-out solder strips in the first battery string group and the second battery string group toward the direction away from the back contact battery cell; setting the end busbar parallel to the bending direction of the corresponding solder strips in the first battery string group and the second battery string group; welding the inclined end busbar and solder strip with a welding head; and using a pressure roller to turn the welded end busbar toward the side of the back contact battery cell where the insulating buffer adhesive is provided.

23. The method for preparing a photovoltaic module according to claim 21, characterized in that, The method further includes bending the lead-out solder strips in the first battery string and the second battery string toward the direction away from the back contact battery cell. The end busbars are positioned at preset locations corresponding to the back-contact solar cells in the first battery string and at preset locations corresponding to the back-contact solar cells in the second battery string. The bent welding strip is turned toward the insulating buffer rubber side by the pressure roller, and the busbar and welding strip are clamped and welded by the welding head and welding support plate.

24. The method for preparing a photovoltaic module according to claim 23, characterized in that, The method of setting the end busbar at a preset position corresponding to the back contact battery cell in the first battery string group and at a preset position corresponding to the back contact battery cell in the second battery string group also includes: setting an adhesive film on the side of the end busbar facing the insulating buffer adhesive and preheating it.

25. The method for preparing a photovoltaic module according to claim 14, characterized in that, The method further includes: the electrode mesh of adjacent back-contact cells in the battery string is the same, and multiple back-contact cells are arranged along a second direction to form a battery string, wherein the rear back-contact cell in two adjacent back-contact cells is rotated 180° relative to the front cell.

26. The method for preparing a photovoltaic module according to claim 25, characterized in that, The battery string is formed by arranging multiple back-contact battery cells along a second direction, and further includes: multiple battery strings forming a first battery string group and a second battery string group, with an intermediate busbar provided between the first battery string group and the second battery string group, and the first battery string group and the second battery string group being arranged symmetrically about the central axis of the intermediate busbar in a first direction.

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