Solar cell, preparation method thereof and photovoltaic module

[0039] The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and structural or functional changes made by those skilled in the art according to these embodiments are all included in the protection scope of the present invention.

[0040] like Figure 1~Figure 10 Shown is a solar cell sheet 100 according to a preferred embodiment of the present invention. The surface of the solar cell sheet 100 is provided with a plurality of bus bars (1, 2), and the edge of the solar cell sheet 100 is provided with a plurality of bus bars (1, 2). The through-grooves 3 corresponding to the gates (1, 2). Those skilled in the art can understand that the “several busbars” mentioned above may be part of the busbars or all of the busbars on the surface of the solar cell sheet 100 .

[0041] By opening the through grooves 3 at the edge of the solar cell 100, the cracking phenomenon of the solar cell 100 during the welding and lamination process can be reduced; , the through grooves 3 are used to accommodate at least part of the interconnecting strips 4 of the adjacent solar cell sheets 100 in series, so that a small space between adjacent solar cells 100 is reserved or a series connection can be realized without setting the space between the sheets. .

[0042] As mentioned in the present invention, "the edge of the solar cell sheet 100 is provided with a plurality of through grooves 3 corresponding to the busbars (1, 2)", it can be understood that at least one edge has a plurality of through grooves 3 corresponding to the busbars (1, 2). 1, 2) Corresponding through-grooves 3, preferably, the through-grooves 3 on each edge perpendicular to the extending direction of the busbars are in one-to-one correspondence with the busbars (1, 2), and the The through groove 3 is located at one end of the busbars (1, 2) along the extending direction thereof. For example, in the following two cases: figure 1 As shown, an edge of one end of the busbars (1, 2) along the extending direction thereof is provided with the through grooves 3 corresponding to the busbars (1, 2) one-to-one; or as shown in Figure 5 As shown, the two edges of the two ends of the busbars (1, 2) along the extending direction thereof are provided with the through grooves 3 corresponding to the busbars (1, 2) one-to-one. On the basis of reducing the cracking phenomenon, when both ends of the busbars (1, 2) are provided with the through grooves 3, the solar cell 100 can be compatible with the solar cells provided with the through grooves 3. The chips 100 are connected in series, and can also be alternately connected in series with the conventional solar cell chips 100 without the through-grooves 3 , and the effect of reducing the chip spacing or eliminating the need to set the chip spacing can also be achieved.

[0043]The through grooves 3 are located at one or both ends of the extension direction of the busbars (1, 2), and the width of the through grooves 3 is not less than the width of the busbars (1, 2), so as to facilitate the connection of the interconnecting bars 4 . In addition, the shape of the through grooves 3 is not limited, as long as the width and thickness of the interconnecting strips 4 are taken into consideration so that the interconnecting strips 4 can pass through. For example, the through groove 3 may be a square of 2mm*2mm, taking into account the width and thickness of the conventional interconnecting strip 4 .

[0044] The solar cell sheet 100 has two edges parallel to each other and perpendicular to the extending direction of the busbars (1, 2), the through grooves 3 are formed on at least one of the edges, and each of the through grooves 3 Located at one end of the extension direction of the busbars (1, 2), the notch of the through groove 3 is disposed away from the busbars (1, 2). On the one hand, the manufacturing process of the solar cell 100 is simple, and on the other hand, such arrangement can facilitate the interconnection bar 4 to pass through the through-groove 3, so that the connection process of the adjacent solar cells 100 is simple, and the existing string welding can still be used. Machine welding.

[0045] The plurality of busbars ( 1 , 2 ) include front busbars 1 respectively located on the front side of the solar cell sheet 100 and/or rear side busbars 2 located on the backside of the solar cell sheet 100 . like Figure 1~Figure 9 As shown, the rear busbar 2 is located in the projection of the front busbar 1 on the back; it can also be understood that the line where the front busbar 1 is located is parallel to the line where the rear busbar 2 is located, and all the The plane where the front main grid 1 and the back main grid 2 are located is perpendicular to the solar cell 100; at this time, the through groove 3 is located at one end of the front main grid 1 and the back main grid 2 at the same time, so that The connection of the interconnection bar 4 is more convenient. Of course, the projection of the front busbar 1 on the backside can also be arranged in a crossed manner with the line where the backside busbar 2 is located, for example, the two are perpendicular to each other; adjacent solar cell sheets 100 can be welded in different directions. , so as to reasonably arrange other connection structures such as bus bars.

[0046] The through groove 3 penetrates through the front and back of the solar cell 100, that is, one end of the through groove 3 is located on the front and the other end is located on the back. When slot 3 is used, one end of the connector is located on the front side, and the other end is located on the back side. For example, the through groove 3 is a straight through groove penetrating the solar cell sheet 100 along the thickness direction of the solar cell sheet 100 , and the preparation process is simple; of course, the through groove 3 can also be a curved groove with any curved path.

[0047] Specifically, one end of the interconnection bar 4 is connected to the front busbar 1 of one of the solar cell sheets 100 , and the other end is connected to the negative busbar of the adjacent solar cell sheet 100 , and a part of the structure of the middle part is accommodated in the through groove. 3, so that only a small space between adjacent solar cells needs to be reserved; or all the middle parts of the interconnecting strips 4 are located in the through grooves 3, and do not need to be between the adjacent solar cells 100. The space between the sheets is reserved; thus, the effective area of ​​the photovoltaic module formed by the solar cell sheets 100 can be increased.

[0048] In addition, the groove wall of the through groove 3 has an insulating structure (not shown), the insulating structure insulates the front busbar 1 from the negative electrode of the solar cell 100 , or the insulating structure makes the back main grid 1 insulate The grid 2 is insulated from the positive electrode of the solar cell sheet 100 ; therefore, when the interconnection bar 4 passes through the through slot 3 , the positive electrode and the negative electrode of the solar cell sheet 100 will not be connected to form a short circuit. The insulating structure can be as follows: after the through groove 3 is formed, an insulating layer is formed on the groove wall of the through groove 3 by using insulating materials or the like; the insulating structure can also be: after the through groove 3 is formed first, then the silicon Photovoltaic devices are fabricated on-chip, so that an insulating layer is formed during the fabrication of photovoltaic devices to prevent the connection between the positive electrode and the negative electrode.

[0049] Any one of the above-mentioned solar cell sheets 100 of the present invention can be as follows Figure 1~Figure 6 A monolithic solar cell 100 is shown, but can also be as Figure 7~Figure 9 A rectangular shaped solar cell 100 is shown to reduce hot spots and cracks and reduce power loss. The rectangular-shaped solar cell sheet 100 is generally formed by cutting a single-piece solar cell sheet 100 , the rectangular-shaped solar cell sheet 100 is provided with a long edge and a short edge, and the through groove 3 is located on the long edge.

[0050] The present invention also provides a method for preparing a solar cell 100, comprising the following steps: preparing a plurality of through grooves 3 on the edge of the silicon wafer; preparing a plurality of bus bars (1, 2) on the surface of the silicon wafer; wherein, the guide 3 Corresponding to the busbars (1, 2).

[0051] Specifically, a through groove 3 penetrating the front and back sides of the silicon wafer is prepared on the silicon wafer; a PN node, a front busbar 1 and a back busbar 2 are prepared on the silicon wafer; wherein, the through groove 3 is located at least in part of the at least one end of the front busbar 1 and/or at least one end of at least part of the rear busbar 2 . The manufacturing process of the PN junction, the front busbar 1 and the back busbar 2 adopts the manufacturing process of the conventional solar cell 100 , and details are not described herein again. For the preparation of the through-groove 3, specifically, the through-groove 3 is formed by cutting a predetermined position of the silicon wafer through a laser cutting technology.

[0052] The steps in the above method are in no particular order. The through-groove 3 can be pre-designed at one end of the front busbar 1 or the back busbar 2 at the edge of the silicon wafer. The PN junction, the front busbar 1 and the back busbar 2 are produced by the solar cell 100 manufacturing process according to the present invention, thereby forming the solar cell 100 of the present invention. This process is less likely to damage the PN junction. After the fabrication is completed, the through-groove 3 has an insulating structure, and there is no need to prepare an insulating structure.

[0053] Of course, the PN junction, the front main gate 1 and the rear main gate 2 can also be prepared on the silicon wafer first; and then the through-trough 3 is formed at one end of the front main gate 1 and/or the rear main gate 2 at the edge of the silicon wafer. In this process, the groove wall of the through groove 3 is the section of the silicon wafer, and it is necessary to use an insulating material or the like to provide an insulating structure.

[0054] The manufacturing method of the rectangular solar cell 100 is as follows: both ends of the busbars (1, 2) in the extending direction have the through grooves 3, and the silicon wafer is cut along the direction perpendicular to the busbars (1, 2). , forming a rectangular solar cell sheet 100 having the through-grooves 3 at one end of the busbars (1, 2).

[0055] Specifically, prepared by the above method as Figure 5 As shown in the solar cell 100 shown, both ends of the front busbar 1 have the through-grooves 3, and a laser cutting process is used to cut the silicon wafer along the direction perpendicular to the front busbar 1 to form as follows: Figure 7 The shown rectangular solar cell sheet 100 with the through-groove 3 at one end of the front busbar 1; and/or as shown in Image 6 As shown, both ends of the back bus gate 2 have the through-grooves 3, and a laser cutting process is used to cut the silicon wafer along the direction perpendicular to the back bus gate 2 to form the following Figure 8 One end of the back busbar 2 shown has a rectangular solar cell sheet 100 having the through-groove 3 .

[0056] Further, the above preparation method further includes the following steps: on the rectangular solar cell sheet 100 having the through-grooves 3 at one end of the busbars (1, 2), no arrangement on the busbars (1, 2) The through groove 3 is prepared at the other end of the through groove 3 to form a rectangular solar cell 100 having the through groove 3 at both ends in the extending direction of the busbars (1, 2). Specifically, on the rectangular solar cell sheet 100 , the through groove 3 is prepared at the other end of the front busbar 1 and/or the rear busbar 2 where the through groove 3 is not provided; Both ends of the front busbar 1 and/or the rear busbar 2 have rectangular solar cell sheets 100 with the through grooves 3 .

[0057] In any of the above preparation methods, the method of forming the through groove 3 after forming the PN junction further includes the step of forming an insulating structure on the wall of the through groove by using insulating materials or the like.

[0058] The present invention also provides a photovoltaic module, comprising two adjacent solar cell sheets and an interconnection bar 4 connecting the two solar cell sheets, at least one of the solar cell sheets is any one of the above-mentioned solar cell sheets 100, The edges thereof are provided with a plurality of the through grooves 3 corresponding to the bus bars (1, 2). The busbars (1, 2) include a front busbar 1 located on the front of the cell and a rear busbar 2 located on the back of the cell; the arrangement of the front busbar 1 and the rear busbar 2 and the effects that can be achieved are referred to above. describe.

[0059] Using the solar cell 100 with the through-grooves 3 can not only reduce the cracking phenomenon of photovoltaic modules in the lamination and welding processes, but also can accommodate at least part of the interconnection when the interconnection bar 4 is connected in series with the front busbar 1 and the rear busbar 2 The strip 4 makes it possible to reduce the inter-sheet spacing between some adjacent solar cell sheets 100 and improve the effective light-emitting area and photoelectric conversion efficiency of the photovoltaic module.

[0060] On the whole, a plurality of solar cells are connected in series through interconnecting bars to form cell strings, and the cell strings are connected in series or in parallel via bus bars; therefore, in the photovoltaic module of the present invention, at least some of the solar cells are any of the above-mentioned solar cells 100. , that is, some of the solar cells are any of the above-mentioned solar cells 100, and the other part is the traditional solar cells 100 without the through-groove 3, which can reduce the risk of cracking to a certain extent and improve the reliability of photovoltaic modules. Effective light-emitting area and photoelectric conversion efficiency; or, all solar cell sheets are any one of the above-mentioned solar cell sheets 100 . In addition, the larger the proportion of the number of solar cells 100 with through-grooves 3 to all the solar cells, the lower the risk of cracking of the photovoltaic module, the larger the effective light emitting area, and the higher the photoelectric conversion efficiency.

[0061] The specific structure of the solar cell sheet 100 with the through-grooves 3 and the connection manner of the solar cell sheet 100 with the interconnection bars 4 will be described in detail below. The solar cell sheet 100 has two edges parallel to each other and perpendicular to the extending direction of the interconnecting strip 4 , the through groove 3 is formed on at least one of the edges, and the interconnecting strip 4 extends from one solar cell sheet 100 . The front side extends to the back side of the adjacent solar cell sheet 100 through the through groove 3; the first end of the interconnecting strip 4 is connected to the front busbar 1 of one of the solar cell sheets 100, and the second end is connected to the adjacent solar cell sheet The back busbar 2 of 100 is connected to realize series connection.

[0062] At least part of the interconnecting strips 4 are accommodated in the through grooves 3, which reduces the risk of cracking at the edge of the solar cell 100 on the one hand, and reserves a small space between adjacent solar cells 100 on the other hand. The series connection can be realized without setting the chip spacing, which can improve the effective light-emitting area and photoelectric conversion efficiency of the photovoltaic module.

[0063] When the at least one edge is provided with a plurality of the through grooves 3 corresponding to all the busbars (1, 2) one-to-one, the distance between the edge and the adjacent solar cell sheets 100 is the same, which can be Very small or no chip spacing.

[0064] The through groove 3 is any one of the above through grooves 3, and its shape and size are not limited. For details, refer to but not limited to the following design methods:

[0065] like Figure 10 As shown, the notch of the through groove 3 is disposed away from the main grid (1, 2), and the through groove 3 has a V-shaped groove wall, and the width of the notch near the edge of the through groove 3 is wider than The width of the groove bottom close to the busbars (1, 2) is convenient for the interconnection bars 4 to pass through.

[0066] The notch of the through groove 3 is arranged away from the busbars (1, 2), and the depth of the through groove 3 along the extension direction of the busbars (1, 2) is not less than 2 mm, which is larger than the existing phase The width of the gap between two adjacent solar cells, after the through-groove 3 accommodates at least part of the interconnecting strips 4, even if there is a gap between two adjacent solar cells 100, the width of the gap is smaller than the existing gap.

[0067]Preferably, the width of the through grooves 3 along the width direction of the busbars (1, 2) is not less than the width of the interconnecting strips 4, which is convenient for the interconnecting strips 4 to pass through without causing the interconnecting strips 4 to be damaged. Extrusion; when the shape of the through groove 3 is an irregular shape, the width of the through groove 3 refers to its minimum width value along the width direction of the busbars (1, 2). The depth of the through grooves 3 along the extension direction of the busbars (1, 2) is not less than the thickness of the interconnection strips 4; then the interconnection strips 4 can be completely accommodated in the through grooves 3, without having to A space between two solar cells 100 is reserved, and there is no space between adjacent solar cells 100 .

[0068] It can be understood by those skilled in the art that "no inter-chip spacing between adjacent solar cell sheets 100" in the present invention does not mean absolutely no spacing, but is unavoidable when the solar cell sheets 100 are allowed to be connected in series. or the allowable gap within the operating error range.

[0069] In the photovoltaic module, the spacing between adjacent solar cells 100 is smaller than the thickness of the interconnecting strips 4, or there is no spacing between adjacent solar cells 100, so that the appearance and color of the photovoltaic modules are consistent. It is better and more beautiful; and the area of ​​photovoltaic modules can be reduced by 1.5%~3%, and the material cost of corresponding photovoltaic modules can be simultaneously reduced by about 1.5%~3%; at the same time, it can also improve the effective luminous area and photoelectric conversion efficiency of photovoltaic modules. The conversion efficiency is increased by 0.3%~0.5%, which meets the requirements of national leaders and customers' requirements for high-efficiency photovoltaic modules. High-efficiency photovoltaic modules can reduce the cost per watt of the module, thereby reducing the cost per kilowatt-hour of the photovoltaic power generation system.

[0070] In addition, the photovoltaic module further includes a bus bar, a backplane, a first encapsulation film, a second encapsulation film, a transparent cover, an aluminum frame, a junction box, a sealing silicone, etc., which are connected in series or in parallel with the above-mentioned battery strings. The positional relationship between the solar cells and the connection method thereof are all technical means commonly used in the art, and reference may be made to the preparation method of the photovoltaic module below, which will not be repeated here.

[0071] The preparation method of the above photovoltaic module is as follows: the interconnection bar 4 passes through the through groove 3 of any one of the above-mentioned solar cell sheets 100 , and the first end and the second end of the interconnection bar 4 are located on the front and back of the solar cell sheet 100 , respectively. ; the first end is connected with the front main grid 1 of the solar cell 100, and the second end is connected with the rear main grid 2 of the adjacent solar cell 100; or the first end is connected with the solar cell The back busbar 2 of the 100 is connected, and the second end is connected to the front busbar 1 of the adjacent solar cell sheets 100 ; the series connection of the adjacent solar cell sheets 100 is completed to form a battery string.

[0072] The preparation method of the photovoltaic module further comprises: after connecting the above-mentioned battery strings in series or in parallel through a bus bar, and then using a laminator to connect the back plate, the first encapsulation film, the battery strings in series or in parallel, the second encapsulation film and the laminator. The transparent cover is laminated to one body; an aluminum frame and a junction box are added, and finally the photovoltaic module is formed after being sealed with silicone. Among them, the lamination process, the installation of the aluminum frame and the junction box, and the silicone seal all adopt the existing technology, and will not be repeated here.

[0073] To sum up, the solar cell 100 of the present invention can reduce the cracking phenomenon during the welding and lamination process by providing the through grooves 3 at the edges, and when two adjacent solar cells 100 are connected in series through the interconnecting bars 3 , the through grooves 3 are used to accommodate at least part of the interconnecting strips 4 of the positive and negative electrodes of the adjacent solar cells 100 in series, so that a small space between adjacent solar cells 100 is reserved or does not need to be set. Concatenation can be achieved.

[0074] In addition, in the photovoltaic module composed of the solar cell sheets 100, the sheet spacing between the adjacent solar cell sheets 100 is smaller than the thickness of the interconnecting strips 4, or there is no sheet spacing between the adjacent solar cell sheets 100, It makes the appearance and color of photovoltaic modules more consistent and more beautiful; and the area of ​​photovoltaic modules is reduced, and the corresponding material costs are simultaneously reduced; at the same time, it can also improve the effective light-emitting area and photoelectric conversion efficiency of photovoltaic modules, and meet the requirements of national leaders and customers for high-efficiency photovoltaics component requirements.

[0075] The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Changes should all be included within the protection scope of the present invention.