A photovoltaic module and a method of manufacturing the same

Abstract

The application discloses a photovoltaic module and a preparation method thereof, and relates to the technical field of photovoltaic modules. The photovoltaic module comprises a cover plate, an upper adhesive film, a cell array, a lower adhesive film and a back plate which are stacked from top to bottom. The cell array comprises a plurality of cell strings, a bus bar, the bus bar is arranged on the back surface of an edge cell piece of the cell string, a plurality of first conductive wires, each first conductive wire comprises a first conductive section, a second conductive section and a third conductive section which is located between the first conductive section and the second conductive section and connects the first conductive section and the second conductive section, wherein the plurality of first conductive sections are connected with a plurality of electrode grid lines of the same polarity of the edge cell piece respectively, the second conductive section is connected with the bus bar, and the third conductive section at least partially extends out of the edge cell piece; the first conductive section and the second conductive section are parallel to each other; and the projection of the second conductive section on the surface of the edge cell piece does not intersect with any first conductive section. The embodiment can effectively improve the preparation yield of the photovoltaic module.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module technology, and in particular to a photovoltaic module and its preparation method. Background Technology

[0002] Currently, in the photovoltaic (PV) module field, high-density encapsulation of PV modules can effectively increase the effective light absorption area of ​​the solar cells and improve module efficiency. High-density encapsulation of PV modules includes folding the busbars to the back of the solar cells, thereby reducing the area occupied by the busbars. However, the current method of folding the busbars to the back of the solar cells generally involves offsetting the portion of the conductive wire extending out of the solar cell at a certain angle, so that it forms a certain offset angle with the portion of the conductive wire welded to the solar cell. Then, the offset conductive wire is welded to the busbar. After the busbar is folded to the back of the solar cell, there may be overlap between the portion of the adjacent conductive wire welded to the busbar and the portion welded to the solar cell, leading to stress concentration in that area and making it prone to problems such as microcracks or cell cracks. Summary of the Invention

[0003] In view of this, the present invention provides a photovoltaic module and its manufacturing method, which can effectively solve the problem that the thickness of the overlapping position increases due to the overlap of adjacent first conductive wires or the overlap of the first conductive segment and the second conductive segment, and becomes a stress concentration point during the lamination process. This reduces the probability of problems such as microcracks and cell cracks in the solar cells and effectively improves the yield of photovoltaic module manufacturing.

[0004] To achieve the above objectives, according to one aspect of the present invention, a photovoltaic module is provided, comprising a cover plate, an upper encapsulant film, a cell array, a lower encapsulant film, and a backsheet stacked from top to bottom, wherein the cell array includes: Multiple battery strings; Busbar; the aforementioned busbar is disposed on the back of the edge battery cells of the aforementioned battery string; A plurality of first conductive wires, each of the first conductive wires including a first conductive segment, a second conductive segment and a third conductive segment located between and connecting the first conductive segment and the second conductive segment, wherein the plurality of the first conductive segments are respectively connected to a plurality of electrode grid lines of the same polarity of the edge battery cell, the second conductive segment is connected to the bus bar, and the third conductive segment extends at least partially out of the edge battery cell; The first conductive segment and the second conductive segment are parallel to each other; The projection of the second conductive segment onto the surface of the edge cell does not intersect with that of any of the first conductive segments.

[0005] Optionally, the angle between the third conductive segment and the surface of the busbar parallel to the edge of the battery cell is 150°-175°.

[0006] Optionally, each of the aforementioned third conductive segments is provided with a bending point close to the aforementioned first conductive segment; The aforementioned bending point is located at the portion of the third conductive segment that extends beyond the edge of the aforementioned battery cell.

[0007] Optionally, the second conductive segment is located on the first surface of the busbar near the edge of the battery cell or on the second surface away from the edge of the battery cell.

[0008] Optionally, the above-mentioned battery array further includes: Insulating gaskets; The insulating pad is disposed between the busbar and the edge battery cell, and the projection of the busbar on the edge battery cell falls within the projection range of the insulating pad on the edge battery cell.

[0009] Optionally, if the bending point is located at the portion of the third conductive segment extending from the edge of the battery cell, The insulating pad extends from the edge of the battery cell along the extension direction of the battery cell in the battery string, and its edge extends to near the bending point to isolate the first connecting segment of the third conductive segment located before the bending point and the second connecting segment located after the bending point.

[0010] Optionally, the distance between the bending point and the edge of the battery cell is less than or equal to 2 mm.

[0011] Optionally, the photovoltaic module further includes: at least two buffer pads; The extension direction of the aforementioned buffer pad is consistent with the extension direction of the aforementioned busbar; A buffer pad is disposed on the back of the edge battery cell and is located on one side of the busbar in the first direction; Another of the aforementioned buffer pads is disposed in the extending direction of the aforementioned battery string and is located between the aforementioned upper adhesive film and the aforementioned lower adhesive film.

[0012] This invention also provides a method for preparing a photovoltaic module, comprising: Step A1: Lay out multiple battery strings with their backs facing up, and lay busbars along the extension direction of the battery strings; Step A2: The first conductive segment of the first conductive wire covers the electrode grid lines of the same polarity on the edge battery cell, and the second conductive segment of the first conductive wire is connected to the busbar near the edge battery cell. The portion of the first conductive wire located between the first conductive segment and the second conductive segment is used as the third conductive segment. Step A3: Weld the first conductive segment to the electrode grid line it covers, and weld the second conductive segment to the busbar it overlaps with. Step A4: Translate the busbar along its length and fold it over to the back of the edge cell, so that the first conductive segment and the second conductive segment are parallel to each other and the projection of the second conductive segment onto the surface of the edge cell does not intersect with that of any of the first conductive segments.

[0013] Optionally, step A2 includes: overlapping and welding the second conductive segment of the first conductive wire to the surface of the busbar; or, Step A2 includes: covering the second conductive segment of the first conductive wire with the busbar and welding it.

[0014] Optionally, step A4 further includes: pressing a specific position of the third conductive segment to form a bending point; folding the busbar with the second conductive segment welded to it along the bending point to the back of the edge battery cell, wherein the bending point after folding is located at the portion of the third conductive segment that extends out of the edge battery cell.

[0015] Optionally, in step A4, before folding the translated busbar to the back of the edge battery cell, step A4 further includes: placing an insulating pad on the back of the edge battery cell or above the busbar, so that after folding, the insulating pad is located between the busbar and the edge battery cell.

[0016] Optionally, step A4 further includes: after folding the busbar to the back of the edge battery cell, placing a buffer pad on the back of the edge battery cell on one side of the busbar in the first direction, and placing another buffer pad in the extending direction of the battery string.

[0017] One embodiment of the above invention has the following advantages or beneficial effects: By setting multiple first conductive wires in the cell array of the photovoltaic module to connect the edge cells of the cell string and the busbar, the first conductive wire includes a first conductive segment connected to the electrode grid line of the same polarity as the edge cell, a second conductive segment connected to the busbar, and a third conductive segment connecting the first conductive segment and the second conductive segment. The first conductive segment and the second conductive segment are parallel to each other, and the projection of the second conductive segment and any first conductive segment on the surface of the edge cell does not intersect. This can effectively solve the problem of increased thickness at the overlapping position caused by the overlap of adjacent first conductive wires or the overlap of the first conductive segment and the second conductive segment, which becomes a stress concentration point during the lamination process. This reduces the probability of problems such as microcracks and cell cracks in the cell and effectively improves the yield of photovoltaic module manufacturing.

[0018] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0019] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of the existing technology in which the portion of the first conductive wire extending beyond the edge of the battery cell is offset at a certain angle; Figure 2 This is a schematic diagram of the overlapping first conductive wires connected after the busbar is folded in the prior art; Figure 3 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a battery array according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a first structure of an edge battery cell, a busbar, a first conductive wire, and an insulating pad according to an embodiment of the present invention. Figure 6 This is a schematic diagram of a second structure of the edge battery cell, busbar, first conductive wire and insulating pad according to an embodiment of the present invention; Figure 7 yes Figure 6 A schematic diagram of the longitudinal section of the structure shown along the first direction; Figure 8 This is a schematic diagram showing the placement of the buffer pad according to an embodiment of the present invention; Figure 9 This is a schematic flowchart of a method for preparing a photovoltaic module according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the edge battery cell, busbar, and first conductive wire obtained through step A2 according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the edge battery cell, busbar, and first conductive wire obtained after the busbar is translated according to an embodiment of the present invention.

[0020] Figure label: 1-Cover plate; 2- Apply adhesive film; 3-Battery array; 31-Battery string; 311-Edge battery cell; 3111-Welding point; 32-First conductive wire; 321-First conductive segment; 322-Second conductive segment; 323-Third conductive segment; 3231-Bending point; 3232-First connecting segment; 3233-Second connecting segment; 33-Busbar; 4- Lower adhesive film; 5-Back panel; 6-Insulating gasket; 7-Buffer pads; x - First direction; y - Second direction. Detailed Implementation

[0021] Currently, the main methods for achieving high-density encapsulation of photovoltaic modules by folding the busbar 33 to the back of the solar cell include: Figure 1 As shown, the machine clamps the portion of each first conductive wire 32 extending out of the edge battery cell 311, offsetting it at a certain angle from the portion of the first conductive wire 32 welded to the edge battery cell 311. Then, it is welded to the busbar 33. After welding, the busbar 33 is folded to the back of the battery cell. There is a certain angle between the portion of the first conductive wire 32 welded to the busbar 33 and the portion welded to the edge battery cell 311. Because there are many first conductive wires 32 and they are densely arranged, clamping and offsetting the first conductive wires 32 requires high machine precision. If the first conductive wire 32 is incorrectly clamped or missed, or if the offset angle is too large, it may lead to overlap between the portion of the first conductive wire 32 welded to the busbar 33 and the portion welded to the edge battery cell 311, or partial overlap between adjacent first conductive wires 32 after the busbar 33 is folded. Figure 2 As shown, folding the busbar 33 to the back of the edge cell 311 increases the thickness of the photovoltaic module. If the adjacent first conductive wires 32 overlap after folding, the thickness of the photovoltaic module will be further increased at that location. This makes that location a stress concentration point during the photovoltaic module lamination process, generating significant stress on the edge cell 311 and leading to microcracks or cell cracks in the photovoltaic module. This problem is particularly pronounced when there are a large number and high density of grid lines welded to the first conductive wires 32 in the edge cell 311, or when the folded busbar 33 is closer to the center of the edge cell 311, thus affecting the yield of the photovoltaic module.

[0022] To address at least one of the aforementioned problems in the prior art, embodiments of the present invention provide a photovoltaic module and a method for its fabrication.

[0023] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0024] It should be noted that, in the embodiments of the present invention, "from top to bottom" refers to the side facing away from sunlight in the thickness direction of the photovoltaic module from the side facing the sunlight when the photovoltaic module is working.

[0025] It should be noted that, unless otherwise specified, the embodiments of the present invention and the technical features thereof can be combined with each other.

[0026] Figure 3 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of the present invention. Figure 3 As shown, the photovoltaic module of this embodiment mainly includes: a cover plate 1, an upper adhesive film 2, a cell array 3, a lower adhesive film 4, and a back sheet 5, which are stacked from top to bottom.

[0027] The cover plate 1 can be made of tempered glass with an anti-reflective coating on its surface. It is mainly used to isolate the internal structure of the photovoltaic module from the outside world, improve the reliability and weather resistance of the photovoltaic module, and at the same time has high light transmittance, so that sunlight can be incident on the front of the cell array 3, thereby improving the power generation of the photovoltaic module.

[0028] The upper adhesive film 2 is mainly disposed between the cover plate 1 and the battery array 3, and the lower adhesive film 4 is mainly disposed between the battery array 3 and the back plate 5.

[0029] Both the upper adhesive film 2 and the lower adhesive film 4 can be prepared using ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), or EPE (EVA-POE-EVE three-layer co-extrusion). They are mainly used to achieve insulation between the battery array 3 and the outside world, sealing and buffering of the battery array 33, preventing moisture and dust from entering the photovoltaic module, and reducing the probability of microcracks and fragments in the battery cell 3211.

[0030] The backsheet 5 can be made of glass, polyvinyl fluoride (PVF), biaxially oriented polyethylene terephthalate film (BOPET), and TPT multilayer composite film composed of PVF. It is mainly used to isolate the internal structure of the photovoltaic module from the outside world, and has the functions of insulation, mechanical protection and improving weather resistance.

[0031] The aforementioned battery array 3 includes: multiple battery strings 31, busbars 33, and multiple first conductive wires 32.

[0032] The battery strings 31 can be arranged along a first direction x or a second direction y, and each battery string 31 includes multiple battery cells arranged along the first direction x. The battery cells located at both ends of the battery string 31 are edge battery cells 311. Different battery strings 31 can be connected in series or in parallel via busbars 33. As an example, such as... Figure 4As shown, the battery array 3 includes four battery strings 31 arranged along the second direction y. Each battery string 31 includes nine battery cells arranged along the first direction x. In each battery string 31, the battery cells arranged in the first and ninth positions are edge battery cells 311. The edge battery cells 311 are connected by a first conductive wire 32 and a bus bar 33. Adjacent battery strings 31 can be connected in series or in parallel through the bus bar 33.

[0033] The aforementioned busbar 33 is disposed on the back side of the edge battery cell 311 of the aforementioned battery string 31 and extends along the second direction y, for connecting adjacent battery strings 31 in series or in parallel.

[0034] The first conductive wire 32 is used to connect the edge battery cell 311 to the busbar 33. The first conductive wire 32 on the same edge battery cell 311 is connected to the electrode grid line of the same polarity on the same edge battery cell 311. In the same battery string 31, the polarity of the electrode grid line of the edge battery cell 311 at one end of the battery string 31 connected to the first conductive wire 32 is opposite to the polarity of the electrode grid line of the edge battery cell 311 at the other end of the battery string 31 connected to the first conductive wire 32. As an example, for the same battery string 31, the first conductive wire 32 connecting the busbar 33 and the edge battery cell 311 at one end of the battery string 31 has a positive polarity for the electrode grid line of the edge battery cell 311 at one end of the battery string 31, and the first conductive wire 32 connecting the busbar 33 and the edge battery cell 311 at the other end of the battery string 31 has a negative polarity for the electrode grid line of the edge battery cell 311 at the other end of the battery string 31.

[0035] like Figure 5 and Figure 6 As shown, each of the first conductive wires 32 includes a first conductive segment 321, a second conductive segment 322, and a third conductive segment 323 located between the first conductive segment 321 and the second conductive segment 322 and connecting the first conductive segment 321 and the second conductive segment 322.

[0036] The aforementioned first conductive segments 321 are respectively connected to multiple electrode grid lines of the same polarity of the edge battery cell 311. Specifically, the first conductive segments 321 and the multiple electrode grid lines of the same polarity of the edge battery cell 311 are welded together, and multiple welding points 3111 exist in the electrode grid lines of the edge battery cell 311 connected to the first conductive segments 321 to increase the welding area between the electrode grid lines and the first conductive segments 321, thereby reducing their contact resistance.

[0037] The second conductive segment 322 is connected to the busbar 33. Specifically, the second conductive segment 322 is welded to the busbar 33 located on the back side of the edge cell 311. Figure 5As shown, the second conductive segment 322 can be located on the first surface of the battery cell 311 near the edge of the busbar 33, or, as... Figure 6 As shown, the second conductive segment 322 can be located on the second surface of the busbar 33 away from the edge of the battery cell 311.

[0038] The third conductive segment 323 extends at least partially beyond the edge battery cell 311, meaning that the projection of the third conductive segment 323 onto the plane containing the surface of the edge battery cell 311 is located outside the projection range of the edge battery cell 311.

[0039] The first conductive segment 321 and the second conductive segment 322 are parallel to each other. The projection of the second conductive segment 322 onto the surface of the edge battery cell 311 does not intersect with the projection of any of the first conductive segments 321. This avoids the overlap between the first conductive segments 321 and the second conductive segments 322 of adjacent first conductive wires 32, and also avoids the overlap between the first conductive segments 321 and the second conductive segments 322 of the same first conductive wire 32. This effectively avoids stress concentration caused by increased thickness at the overlapping position, thus preventing problems such as microcracks or cracks.

[0040] Furthermore, the aforementioned battery array 3 may also include multiple second conductive wires. These second conductive wires are used to connect battery cells (including edge battery cells 311) arranged in the first direction x in the same battery string 31 in series. Specifically, for any two adjacent battery cells in the same battery string 31, one end of the second conductive wire can be electrically connected to the electrode grid lines on one of the battery cells, and the other end can be electrically connected to the electrode grid lines on the adjacent battery cell. Furthermore, the electrode grid lines of the two battery cells connected by the same second conductive wire have opposite polarities.

[0041] Optionally, when the solar cell is a back-contact solar cell, the second conductive wire is disposed on the back side of the solar cell; when the solar cell is a bifacial electrode solar cell, one end of the second conductive wire is connected to the electrode grid line on the front side of one of the two adjacent solar cells, and the other end is connected to the electrode grid line on the back side of the other of the two adjacent solar cells.

[0042] In one alternative embodiment, such as Figure 7 As shown, the angle θ between the third conductive segment 323 and the surface of the busbar 33 parallel to the edge battery cell 311 is 150°-175°. This further avoids the problem of the corner at the connection point between the second conductive segment 322 and the third conductive segment 323 being too sharp, becoming a stress concentration point during lamination and causing microcracks or fragmentation of the battery cell. As an example, the angle θ between the third conductive segment 323 and the surface of the busbar 33 parallel to the edge battery cell 311 can be 150°, 153°, 155°, 157°, 160°, 162°, 165°, or 175°, etc.

[0043] In one alternative embodiment, such as Figure 7 As shown, each of the aforementioned third conductive segments 323 is provided with a bending point 3231 near the aforementioned first conductive segment 321. The third conductive segment 323 includes a first connecting segment 3232 located before the bending point 3231 and a second connecting segment 3233 located after the bending point 3231. One end of the first connecting segment 3232 is connected to the first conductive segment 321, and the other end is connected to the second connecting segment 3233; one end of the second connecting segment 3233 is connected to the first connecting segment 3232, and the other end is connected to the second conductive segment 322.

[0044] The bending point 3231 is located on the portion of the third conductive segment 323 that extends out of the edge battery cell 311. That is, the projection of the bending point 3231 on the plane of the edge battery cell 311 is located outside the projection range of the edge battery cell 311, thereby avoiding the bending point 3231 from becoming a stress concentration point.

[0045] In one alternative embodiment, such as Figure 5 , Figure 6 and Figure 7 As shown, the battery array 3 also includes an insulating pad 6. The extending direction of the insulating pad 6 is consistent with the extending direction of the busbar 33. It can be disposed between the busbar 33 and the edge battery cell 311, and the projection of the busbar 33 on the edge battery cell 311 falls within the projection range of the insulating pad 6 on the edge battery cell 311. This is to isolate the busbar 33 and the edge battery cell 311 through the insulating pad 6, and avoid the busbar 33 directly contacting the battery cell, which could lead to leakage or short circuit problems.

[0046] The insulating pad 6 can be a single-layer structure or a multi-layer stacked structure. For example, the insulating pad 6 can be a single-layer structure made of polyethylene terephthalate (PET) or polyimide (PI), or a stacked structure made of ethylene-vinyl acetate copolymer (EVA)-PET-EVA or EVA-PI-EVA, so as to enhance the buffering capacity through EVA.

[0047] Furthermore, the insulating pad 6 extends along the extension direction of the battery string 31 beyond the edge of the edge battery piece 311, and the edge of the insulating pad 6 extends close to the bending point 3231 to isolate the first connecting segment 3232 before the bending point 3231 and the second connecting segment 3233 after the bending point 3231. On the one hand, this can provide a certain buffer for the first connecting segment 3232 and the second connecting segment 3233, and on the other hand, it can achieve the isolation of the first connecting segment 3232 and the second connecting segment 3233.

[0048] Optionally, the distance between the bending point 3231 and the edge battery cell 311 is less than or equal to 2 mm to avoid the bending point 3231 being too far from the edge of the edge battery cell 311, which would affect the current transmission efficiency. As an example, the distance between the bending point 3231 and the edge battery cell 311 can be 0.5 mm, 0.7 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm, etc.

[0049] In one alternative embodiment, such as Figure 8 As shown, the photovoltaic module may further include at least two buffer pads 7. The extending direction of the buffer pads 7 is consistent with the extending direction of the busbar 33. One buffer pad 7 is disposed on the back side of the edge cell 311 and located on one side of the first direction x of the busbar 33; the other buffer pad 7 is disposed in the extending direction of the cell string 31 and located between the upper adhesive film 2 and the lower adhesive film 4, that is, disposed next to the edge of the edge cell 311 on the side where the busbar 33 is disposed, and does not overlap with the edge cell 311.

[0050] Both buffer pads 7 do not overlap with the busbar 33 and can be made of insulating and elastic materials to buffer the large stress that the overlapping position experiences during lamination due to the increased thickness at the folded position caused by the busbar 33 being folded over the back of the edge battery cell 311.

[0051] Optionally, the buffer pad 7 can be a single-layer or multi-layer structure formed of EVA, PET, or polyolefin elastomer (POE), such as a three-layer structure formed of EVA-PET-EVA, preferably made of the same material as the upper adhesive film 2 and the lower adhesive film 4. The width of the buffer pad 7 located on the back of the edge battery cell 311 is 20mm-40mm, or it can be the same as the width of another buffer pad 7, and its basis weight can be 400g / m³. 2To buffer the excessive stress at the overlapping position caused by the thickness of the insulating pad 6 and the busbar 33, the buffer pad 7, located next to the edge of the edge battery cell 311 where the busbar 33 is located, has a width that matches the minimum width of the edge battery cell 311 from the edge of the cover plate 1, preferably 13 mm, and a basis weight of 400 g / m². 2 Or slightly greater than 400g / m 2 This is to buffer the problem of excessive stress at the overlapping position caused by the thickness of the first conductive wire 32, the edge battery sheet 311, the insulating pad 6, and the busbar 33. As an example, the width of the buffer pad 7 located on the back of the edge battery sheet 311 can be 20mm, 25mm, 30mm, 35mm, or 40mm, etc.

[0052] It should be noted that in photovoltaic modules, since the buffer pad 7 has already undergone lamination, it may melt under heat at the lamination temperature and may not be able to completely maintain the strip shape it was laid out in. It may also fuse with the upper adhesive film 2 and the lower adhesive film 4, thereby providing a certain buffering and shock absorption performance for the photovoltaic module and assisting in edge sealing.

[0053] It should be noted that, Figure 8 The example shown is merely illustrative, illustrating two battery strings 31 and two battery cells in each battery string 31. Depending on the actual design and requirements, the battery array 3 may include any number of battery strings 31, and each battery string 31 may include any number of battery cells; no specific limitation is made here.

[0054] According to the photovoltaic module of the present invention, by providing a plurality of first conductive wires 32 in the cell array 3 of the photovoltaic module to connect the edge cell 311 of the cell string 31 and the busbar 33, the first conductive wires 32 include a first conductive segment 321 connected to the electrode grid line of the edge cell 311 with the same polarity, a second conductive segment 322 connected to the busbar 33, and a third conductive segment 323 connecting the first conductive segment 321 and the second conductive segment 322. The first conductive segment 321 and the second conductive segment 322 are parallel to each other, and the projection of the second conductive segment 322 and any first conductive segment 321 on the surface of the edge cell 311 does not intersect. This can effectively solve the problem of increased thickness at the overlapping position caused by the overlap of adjacent first conductive wires 32 or the overlap of the first conductive segment 321 and the second conductive segment 322, which becomes a stress concentration point during the lamination process. This reduces the probability of problems such as microcracks and cell cracks in the cell and effectively improves the yield of photovoltaic module manufacturing.

[0055] In addition, in the photovoltaic module of this embodiment, the busbar 33 is disposed on the back of the edge cell 311 and is not exposed on the front, so that the busbar 33 does not occupy the area of ​​the photovoltaic module, thereby increasing the module packaging density, increasing the effective light absorption area of ​​the cells in the photovoltaic module, and improving the efficiency of the photovoltaic module.

[0056] like Figure 9 As shown, this embodiment of the invention also provides a method for preparing a photovoltaic module, including the following steps A1 to A4: Step A1: Lay out multiple battery strings 31 with the back side facing up, and lay busbars 33 in the extending direction of the battery strings 31; Before step A1, the above preparation method may also include step A0, sequentially laying the cover plate 1 and the adhesive film 2 to lay the battery string 31 on the adhesive film 2.

[0057] Step A1 specifically includes: connecting multiple battery cells in series along the first direction x using a second conductive wire to form a battery string 31; wherein, one end of the second conductive wire is welded to the positive electrode grid line of one of the two adjacent battery cells, and the other end is welded to the negative electrode grid line of the other of the two adjacent battery cells. The multiple battery strings 31 are laid on the adhesive film 2 according to a pre-set battery string 31 arrangement, and busbars 33 are laid next to the edge battery cells 311 in the extending direction of the battery strings 31. Here, the edge battery cells 311 include the battery cells located at both ends of the battery strings 31.

[0058] Optionally, the use of a second conductive wire to connect multiple battery cells into a battery string 31 can be achieved by infrared stringing, but is not limited to this method.

[0059] Step A2: Cover the electrode grid lines of the same polarity on the edge battery cell 311 with the first conductive segment 321 of the first conductive wire 32, and overlap the second conductive segment 322 of the first conductive wire 32 with the busbar 33 near the edge battery cell 311. The portion of the first conductive wire 32 located between the first conductive segment 321 and the second conductive segment 322 serves as the third conductive segment 323. Please refer to [reference needed]. Figure 10 ; Specifically, for one edge battery cell 311 at both ends of a battery string 31, the first conductive segment 321 of the first conductive wire 32 can cover the electrode grid line of the positive conductivity type on the edge battery cell 311; for the other edge battery cell 311 at both ends of the same battery string 31, the first conductive segment 321 of the first conductive wire 32 can cover the electrode grid line of the negative conductivity type on the edge battery cell 311.

[0060] Optionally, the second conductive segment 322 of the first conductive wire 32 can be overlapped and welded to the surface of the busbar 33 near the edge battery cell 311, so that after the busbar 33 is folded, the second conductive segment 322 is located on the first surface of the busbar 33 near the edge battery cell 311.

[0061] Alternatively, the busbar 33 can be used to cover and weld the second conductive segment 322 of the first conductive wire 32, so that after the busbar 33 is folded, the second conductive segment 322 is located on the second surface of the busbar 33 away from the edge battery cell 311.

[0062] Step A3: Weld the first conductive segment 321 to the electrode grid line it covers, and weld the second conductive segment 322 to the busbar 33 it overlaps with. Step A4: Translate the busbar 33 along its length and fold it over to the back of the edge battery cell 311 so that the first conductive segment 321 and the second conductive segment 322 are parallel to each other and the projection of the second conductive segment 322 onto the surface of the edge battery cell 311 does not intersect with the projection of any of the first conductive segments 321 onto the surface of the edge battery cell 311.

[0063] like Figure 11 As shown, since the second conductive segment 322 has been welded to the busbar 33 and the first conductive segment 321 has been welded to the electrode grid line in the edge battery cell 311, after the busbar 33 is translated, the second conductive segment 322 and the first conductive segment 321 are parallel to each other, while there is a certain angle between the third conductive segment 323 and the first conductive segment 321, and there is a certain angle between the third conductive segment 323 and the second conductive segment 322.

[0064] Optionally, the included angle α between the second conductive segment 322 and the third conductive segment 323 is 5°-30° to avoid the problem that an excessively large angle would cause the busbar 33 to translate too much along its length, the edge of the busbar 33 to shift to the outside of the edge battery cell 311, and the projection of the busbar 33 onto the surface of the edge battery cell 311 to exceed the range of the edge battery cell 311 after the busbar 33 is folded. As an example, the included angle between the second conductive segment 322 and the third conductive segment 323 can be 5°, 10°, 15°, 20°, 25°, or 30°, etc.

[0065] After the busbar 33 is folded to the back of the edge battery cell 311, a battery array 3 is obtained, wherein the first conductive segment 321, the second conductive segment 322, and the third conductive segment 323 of the same first conductive wire 32 do not overlap, and the first conductive segment 321 and the second conductive segment 322 of different first conductive wires 32 also do not overlap.

[0066] Step A4 also includes: sequentially laying the undercoat film 4 and the backsheet 5 on the battery array 3, and after lamination, flipping it over to obtain the photovoltaic module.

[0067] In an optional embodiment, before or during the translation of the busbar 33, step A4 may further include: pressing a specific position of the third conductive segment 323 to form a bending point 3231; folding the busbar 33, to which the second conductive segment 322 is welded, along the bending point 3231 to the back of the edge battery cell 311, wherein the folded bending point 3231 is located at the portion of the third conductive segment 323 extending out of the edge battery cell 311.

[0068] The specific location refers to the position of the pre-set bending point 3231 in the third conductive segment 323. Specifically, a pressure plate or clamp can be used to press and solidify the specific location of the third conductive segment 323 to form an indentation fulcrum at that specific location, which facilitates the subsequent folding of the busbar 33. At the same time, it can make the bending point 3231 of different first conductive wires 32 connected to the same busbar 33 have the same position, avoiding the situation that the bending point 3231 is not fixed during folding and the length of the first connecting segment 3232 in different first conductive wires 32 is different.

[0069] It should be noted that the specific position can be pressed and solidified either before or during the translation of the busbar 33. That is, after the busbar 33 has been translated a certain distance along its length, the specific position of the third conductive segment 323 can be pressed and solidified, and then the busbar 33 can be prompted to continue to translate along its length.

[0070] After the busbar 33 is folded, a bending point 3231 is formed at a specific position, and the bending point 3231 is located on the outside of the edge battery cell 311. This not only avoids the pressure on the edge battery cell 311 when the specific position is pressed, but also reduces the edge stress of the edge battery cell 311 during the lamination process, and reduces the probability of the edge battery cell 311 developing microcracks or cracks.

[0071] In an optional embodiment, before folding the translated busbar 33 to the back of the edge battery cell 311 in step A4, step A4 may further include: placing an insulating pad 6 on the edge of the edge battery cell 311 where the folded busbar 33 will be placed, so that after folding, the insulating pad 6 can be located between the busbar 33 and the edge battery cell 311. Optionally, to prevent the placed insulating pad 6 from shifting, the insulating pad 6 can be hot-pressed to fix it to the back of the edge battery cell 311.

[0072] Additionally, before folding, step A4 may include placing an insulating pad 6 above the busbar 33 so that after folding, the insulating pad 6 is located between the busbar 33 and the edge battery piece 311. Optionally, to prevent the placed insulating pad 6 from shifting, the insulating pad 6 may be hot-pressed to fix it to the busbar 33.

[0073] By setting an insulating pad 6 on the back of the edge battery cell 311 or above the busbar 33, the busbar 33 and the edge battery cell 311 can be effectively isolated to avoid short circuits or leakage.

[0074] The insulating pad 6 can extend from one edge of the edge battery cell 311 near the folded busbar 33, and further extend to the position near the bending point 3231 of the multiple first conductive wires 32 connected to the same busbar 33, further ensuring that the bending points 3231 of the multiple first conductive wires 32 connected to the same busbar 33 are aligned when folded, and isolating the first connecting segment 3232 before the bending point 3231 and the second connecting segment 3233 after the bending point 3231 in the third conductive segment 323.

[0075] In an optional embodiment, step A4 may further include: after folding the busbar 33 to the back of the edge battery cell 311, placing a buffer pad 7 on the back of the edge battery cell 311 on the side of the busbar 33 in the first direction x, and placing another buffer pad 7 in the extending direction of the battery string 31.

[0076] Specifically, a buffer pad 7 is placed on the upper adhesive film 2 next to the edge of the edge cell 311 where the busbar 33 is located, along the extension direction of the cell string 31. This fills the height step caused by the thickness of the busbar 33, insulating pad 6, first conductive wire 32, and edge cell 311, distributing the lamination pressure and reducing the probability of microcracks or cracks in the edge cell 311. The buffer pad 7 can be made of insulating material to maintain a stable creepage distance, preventing the upper adhesive film 2 and lower adhesive film 4 between the edge cell 311 and the edge of the photovoltaic module from being squeezed and thinned, leading to short circuits. Another buffer pad 7 is placed on the side of the busbar 33 on the back of the edge cell 311 in the first direction x, that is, on the side of the busbar 33 on the back of the edge cell 311 away from the edge of the cell string 31. This fills the height step caused by the busbar 33, insulating pad 6, and first conductive wire 32, distributing the lamination pressure and reducing the probability of microcracks or cracks in the edge cell 311.

[0077] Optionally, the width of the buffer pad 7 disposed on the upper adhesive film 2 can be the same as the distance between the edge battery piece 311 and the edge of the cover plate 1, and the width of the buffer pad 7 disposed on the back of the edge battery piece 311 can be the same as the width of the buffer pad 7 disposed on the upper adhesive film 2, or it can be 20mm-40mm.

[0078] According to the photovoltaic module manufacturing method of the present invention, after welding the second conductive segment 322 of the first conductive wire 32 to the busbar 33, the busbar 33 is then translated along its length. After the translated busbar 33 is folded over the back of the edge cell 311, the first conductive segment 321 and the second conductive segment 322 are parallel to each other, and the projections of the second conductive segment 322 and any first conductive segment 321 on the surface of the edge cell 311 do not intersect. This avoids the situation where the overlapping position is thick due to the overlap of different conductive segments of the same conductive wire or adjacent first conductive wires 32, which would become a stress concentration point during the photovoltaic module lamination process. This reduces the probability of microcracks or fragments in the cell and improves the manufacturing yield of the photovoltaic module.

[0079] In addition, the above preparation method has a simple manufacturing process, eliminating the need to clamp and stagger the first conductive wire 32 one by one, thus eliminating the precision requirements on the equipment caused by clamping the first conductive wire 32, simplifying the preparation process and improving the preparation efficiency.

[0080] In summary, the embodiments of the present invention provide the following technical solutions: Technical Solution 1: A photovoltaic module, comprising a cover plate 1, an upper adhesive film 2, a cell array 3, a lower adhesive film 4, and a backsheet 5 stacked from top to bottom, wherein the cell array 3 includes: Multiple battery strings 31; Busbar 33; the busbar 33 is disposed on the back side of the edge battery piece 311 of the battery string 31; A plurality of first conductive wires 32, each first conductive wire 32 including a first conductive segment 321, a second conductive segment 322 and a third conductive segment 323 located between and connecting the first conductive segment 321 and the second conductive segment 322, wherein the plurality of first conductive segments 321 are respectively connected to a plurality of electrode grid lines of the same polarity of the edge battery cell 311, the second conductive segment 322 is connected to the bus bar 33, and the third conductive segment 323 extends at least partially out of the edge battery cell 311; The first conductive segment 321 and the second conductive segment 322 are parallel to each other; The projection of the second conductive segment 322 onto the surface of the edge battery cell 311 does not intersect with that of any of the first conductive segments 321.

[0081] Technical Solution 2: The photovoltaic module according to Technical Solution 1, The angle between the third conductive segment 323 and the surface of the busbar 33 parallel to the edge battery cell 311 is 150°-175°.

[0082] Technical Solution 3: The photovoltaic module according to Technical Solution 1, Each of the third conductive segments 323 is provided with a bending point 3231 close to the first conductive segment 321; The bending point 3231 is located at the portion of the third conductive segment 323 that extends from the edge of the battery cell 311.

[0083] Technical Solution 4: The photovoltaic module according to Technical Solution 1, The second conductive segment 322 is located on the first surface of the busbar 33 near the edge battery cell 311 or on the second surface away from the edge battery cell 311.

[0084] Technical solution 5: The photovoltaic module according to technical solution 1 or 3 further includes: Insulating gasket 6; The insulating pad 6 is disposed between the busbar 33 and the edge battery cell 311, and the projection of the busbar 33 on the edge battery cell 311 falls within the projection range of the insulating pad 6 on the edge battery cell 311.

[0085] Technical Solution 6: In the photovoltaic module according to Technical Solution 5, when the bending point 3231 is located at the portion of the third conductive segment 323 extending from the edge cell 311, The insulating pad 6 extends the edge battery piece 311 along the extension direction of the battery string 31, and its edge extends to near the bending point 3231 to isolate the third conductive segment 323 from the first connecting segment 3232 before the bending point 3231 and the second connecting segment 3233 after the bending point 3231.

[0086] Technical Solution 7: The photovoltaic module according to Technical Solution 3 or 6, The distance between the bending point 3231 and the edge battery cell 311 is less than or equal to 2 mm.

[0087] Technical solution 8: The photovoltaic module according to technical solution 1 further includes: at least two buffer pads 7; The extension direction of the buffer pad 7 is consistent with the extension direction of the busbar 33; A buffer pad 7 is disposed on the back side of the edge battery cell 311 and located on one side of the busbar 33 in the first direction x. Another buffer pad 7 is disposed in the extending direction of the battery string 31 and is located between the upper adhesive film 2 and the lower adhesive film 4.

[0088] Technical Solution 9: A method for preparing a photovoltaic module, comprising: Step A1: Lay out multiple battery strings 31 with the back side facing up, and lay busbars 33 in the extending direction of the battery strings 31; Step A2: The first conductive segment 321 of the first conductive wire 32 covers the electrode grid lines of the same polarity of the edge battery cell 311, and the second conductive segment 322 of the first conductive wire 32 overlaps with the busbar 33 near the edge battery cell 311. The portion of the first conductive wire 32 located between the first conductive segment 321 and the second conductive segment 322 is used as the third conductive segment 323. Step A3: Weld the first conductive segment 321 to the electrode grid line it covers, and weld the second conductive segment 322 to the busbar 33 it overlaps with; Step A4: Translate the busbar 33 along its length and fold it over to the back of the edge battery cell 311 so that the first conductive segment 321 and the second conductive segment 322 are parallel to each other and the projection of the second conductive segment 322 onto the surface of the edge battery cell 311 does not intersect with the projection of any of the first conductive segments 321.

[0089] Technical Solution 10: The method for preparing photovoltaic modules according to Technical Solution 9. Step A2 includes: overlapping and welding the second conductive segment 322 of the first conductive wire 32 to the surface of the busbar 33; or, Step A2 includes: covering the second conductive segment 322 of the first conductive wire 32 with the busbar 33 and welding it.

[0090] Technical Solution 11: The method for preparing photovoltaic modules according to Technical Solution 9, Step A4 further includes: pressing a specific position of the third conductive segment 323 to form a bending point 3231; folding the busbar 33, to which the second conductive segment 322 is welded, along the bending point 3231 to the back of the edge battery cell 311, wherein the folded bending point 3231 is located at the portion of the third conductive segment 323 that extends out of the edge battery cell 311.

[0091] Technical Solution 12: According to the photovoltaic module manufacturing method described in Technical Solution 9, in step A4, before folding the translated busbar 33 to the back of the edge cell 311, step A4 further includes: An insulating pad 6 is placed on the back of the edge battery cell 311 or above the busbar 33 so that the insulating pad 6 is located between the busbar 33 and the edge battery cell 311 after folding.

[0092] Technical Solution 13: According to the photovoltaic module manufacturing method described in Technical Solution 9, step A4 further includes: after folding the busbar 33 to the back of the edge cell 311, placing a buffer pad 7 on the back of the edge cell 311 on one side of the busbar 33 in the first direction x, and placing another buffer pad 7 in the extending direction of the cell string 31.

[0093] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A photovoltaic module, comprising a cover plate (1), an upper adhesive film (2), a cell array (3), a lower adhesive film (4), and a backsheet (5) stacked from top to bottom, characterized in that, The battery array (3) includes: Multiple battery strings (31); Busbar (33); the busbar (33) is disposed on the back side of the edge battery cell (311) of the battery string (31); A plurality of first conductive wires (32), each of the first conductive wires (32) including a first conductive segment (321), a second conductive segment (322) and a third conductive segment (323) located between and connecting the first conductive segment (321) and the second conductive segment (322), wherein the plurality of first conductive segments (321) are respectively connected to a plurality of electrode grid lines of the same polarity of the edge battery cell (311), the second conductive segment (322) is connected to the bus bar (33), and the third conductive segment (323) extends at least partially out of the edge battery cell (311). The first conductive segment (321) and the second conductive segment (322) are parallel to each other; The projection of the second conductive segment (322) onto the surface of the edge battery cell (311) does not intersect with that of any of the first conductive segments (321).

2. The photovoltaic module according to claim 1, characterized in that, The angle between the third conductive segment (323) and the surface of the busbar (33) parallel to the edge battery cell (311) is 150°-175°.

3. The photovoltaic module according to claim 1, characterized in that, Each of the third conductive segments (323) is provided with a bending point (3231) near the first conductive segment (321). The bending point (3231) is located at the portion of the third conductive segment (323) that extends out of the edge battery cell (311).

4. The photovoltaic module according to claim 1, characterized in that, The second conductive segment (322) is located on the first surface of the busbar (33) near the edge cell (311) or on the second surface away from the edge cell (311).

5. The photovoltaic module according to claim 1 or 3, characterized in that, Also includes: Insulating pad (6); The insulating pad (6) is disposed between the busbar (33) and the edge battery cell (311), and the projection of the busbar (33) on the edge battery cell (311) falls within the projection range of the insulating pad (6) on the edge battery cell (311).

6. The photovoltaic module according to claim 5, characterized in that, When the bending point (3231) is located at the portion of the third conductive segment (323) extending from the edge of the battery cell (311), The insulating pad (6) extends out of the edge battery piece (311) along the extension direction of the battery string (31), and its edge extends to near the bend point (3231) to isolate the third conductive segment (323) from the first connecting segment (3232) before the bend point (3231) and the second connecting segment (3233) after the bend point (3231).

7. The photovoltaic module according to claim 3 or 6, characterized in that, The distance between the bending point (3231) and the edge battery cell (311) is less than or equal to 2 mm.

8. The photovoltaic module according to claim 1, characterized in that, Also includes: At least two cushioning pads (7); The extension direction of the buffer pad (7) is consistent with the extension direction of the busbar (33); One of the buffer pads (7) is disposed on the back side of the edge battery cell (311) and is located on one side of the busbar (33) in the first direction (x); Another buffer pad (7) is disposed in the extension direction of the battery string (31) and is located between the upper adhesive film (2) and the lower adhesive film (4).

9. A method for manufacturing a photovoltaic module, characterized in that, include: Step A1: Lay out multiple battery strings (31) with the back facing up, and lay busbars (33) in the extending direction of the battery strings (31). Step A2: The first conductive segment (321) of the first conductive wire (32) is used to cover the electrode grid lines of the same polarity of the edge battery cell (311), and the second conductive segment (322) of the first conductive wire (32) is connected to the busbar (33) near the edge battery cell (311). The portion of the first conductive wire (32) located between the first conductive segment (321) and the second conductive segment (322) is used as the third conductive segment (323). Step A3: Weld the first conductive segment (321) to the electrode grid line it covers, and weld the second conductive segment (322) to the busbar (33) it overlaps with; Step A4: Translate the busbar (33) along its length direction and fold the translated busbar (33) to the back of the edge battery cell (311) so that the first conductive segment (321) and the second conductive segment (322) are parallel to each other, and the projection of the second conductive segment (322) onto the surface of the edge battery cell (311) does not intersect with the projection of any of the first conductive segments (321).

10. The method for preparing a photovoltaic module according to claim 9, characterized in that, Step A2 includes: overlapping and welding the second conductive segment (322) of the first conductive wire (32) to the surface of the busbar (33); or, Step A2 includes: covering the second conductive segment (322) of the first conductive wire (32) with the busbar (33) and welding it.

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