Back contact solar cell and manufacturing method thereof, back contact solar cell mother sheet, photovoltaic module

Abstract

This invention relates to a back-contact solar cell, its fabrication method, a back-contact solar cell wafer, and a photovoltaic module. The back-contact solar cell includes: a substrate comprising a first surface and a plurality of side surfaces adjacent to the first surface, the first surface including an edge region adjacent to the side surfaces; a plurality of first-doped semiconductor portions and a plurality of second-doped semiconductor portions, alternately and spaced apart along a first predetermined direction on the first surface, the first-doped semiconductor portions and the second-doped semiconductor portions having opposite doping types and being insulated from each other; a first electrode electrically connected to the first-doped semiconductor portions, and a second electrode electrically connected to the second-doped semiconductor portions; and a passivation portion disposed in the edge region and insulated from the first-doped semiconductor portions and the second-doped semiconductor portions. The back-contact solar cell, back-contact solar cell wafer, and photovoltaic module of this application have high cell efficiency.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a back-contact solar cell and its manufacturing method, a back-contact solar cell wafer, and a photovoltaic module. Background Technology

[0002] Back-contact solar cells emerged in the 1970s. They feature finger-like, interlaced P-regions and N-regions on the back of the cell, with both the positive and negative electrodes located on the back. The front is free of metal shielding, significantly improving optical absorption. However, these back-contact solar cells suffer from significant edge recombination at their edges, negatively impacting efficiency. Summary of the Invention

[0003] Therefore, it is necessary to provide a highly efficient back-contact solar cell and its manufacturing method, a back-contact solar cell wafer, and a photovoltaic module.

[0004] The first aspect of this application provides a back-contact solar cell, comprising:

[0005] The substrate includes a first surface and a plurality of side surfaces adjacent to the first surface, the first surface including edge regions adjacent to the side surfaces;

[0006] Multiple first-doped semiconductor portions and multiple second-doped semiconductor portions are arranged alternately and at intervals on the first surface along a first preset direction. The first-doped semiconductor portions and the second-doped semiconductor portions have opposite doping types and are insulated from each other.

[0007] A first electrode and a second electrode, the first electrode being electrically connected to a first doped semiconductor portion, and the second electrode being electrically connected to a second doped semiconductor portion; and

[0008] The passivation portion is located in the edge region and is insulated from the first doped semiconductor portion and the second doped semiconductor portion.

[0009] In one embodiment, the first doped semiconductor portion includes a first doped semiconductor layer, the second doped semiconductor portion includes a second doped semiconductor layer, and the passivation portion includes a third doped semiconductor layer.

[0010] The doping type of the third doped semiconductor layer is the same as that of the first or second doped semiconductor layer.

[0011] In one embodiment, the passivation portion has the same film structure as the first doped semiconductor portion or the second doped semiconductor portion.

[0012] In one embodiment, the doping type of the third doped semiconductor layer is the same as that of the first doped semiconductor layer, and the minimum spacing between the passivation portion and any second doped semiconductor portion is greater than 50 micrometers; or

[0013] The doping type of the third doped semiconductor layer is the same as that of the second doped semiconductor layer, and the minimum spacing between the passivation portion and any of the first doped semiconductor portions is greater than 50 micrometers.

[0014] In one embodiment, the passivation portion extends along at least a portion of the outer contour of the first surface and is configured as a continuous or discontinuous structure.

[0015] In one embodiment, the passivation portion is configured as a frame-like structure that extends continuously along the outer contour line of the first surface.

[0016] In one embodiment, the outer edge of the passivation portion coincides with the outer contour line of the first surface;

[0017] Alternatively, the distance between the outer edge of the passivation portion and the outer contour line of the first surface may be less than 20 micrometers.

[0018] In one embodiment, a continuous inwardly extending region along the outer contour of the first surface defines a frame-shaped edge region, the minimum width of which along a first direction is greater than 500 micrometers. The first direction is parallel to the first surface and extends inwardly from the outer contour of the first surface.

[0019] In one embodiment, the passivation portion has a width of 200 micrometers to 500 micrometers along the first direction.

[0020] In one embodiment, the back contact solar cell further includes a first passivation layer;

[0021] The first passivation layer is disposed on the substrate-averse surface of the first doped semiconductor portion and the second doped semiconductor portion, and covers the passivation portion;

[0022] The first electrode and the second electrode are disposed on the first passivation layer and penetrate the first passivation layer, so as to be electrically connected to the first doped semiconductor portion and the second doped semiconductor portion, respectively.

[0023] A second aspect of this application provides a back-contact solar cell wafer, comprising at least two back-contact solar cells as described above, wherein the corresponding side edges of adjacent back-contact solar cells are connected to each other to form an integral structure.

[0024] In one embodiment, passivation portions are provided on corresponding side edges of adjacent back-contact solar cells, and these passivation portions on corresponding side edges of adjacent back-contact solar cells are connected to each other to form a continuous pattern; or

[0025] The passivation portion is not provided on the corresponding side edges of the integral structure.

[0026] A third aspect of this application provides a photovoltaic module including at least one battery string, the battery string including at least two back-contact solar cells as described above.

[0027] A fourth aspect of this application provides a method for manufacturing a back-contact solar cell, comprising:

[0028] A substrate is provided, the substrate including a first surface and a plurality of side surfaces adjacent to the first surface, the first surface including edge regions adjacent to the side surfaces;

[0029] A passivation portion, a plurality of first doped semiconductor portions, and a plurality of second doped semiconductor portions are formed on a first surface. The passivation portion is located in the edge region and is insulated from the first doped semiconductor portions and the second doped semiconductor portions. The first doped semiconductor portions and the second doped semiconductor portions have opposite doping types and are insulated from each other.

[0030] A first electrode and a second electrode are formed on one side of the first surface of the substrate. The first electrode is electrically connected to the first doped semiconductor portion, and the second electrode is electrically connected to the second doped semiconductor portion.

[0031] In one embodiment, the passivation portion is formed in the same step as either the first doped semiconductor portion or the second doped semiconductor portion.

[0032] In one embodiment, the passivation portion and the first doped semiconductor portion are formed in the same step; the step of forming the passivation portion, the plurality of first doped semiconductor portions, and the plurality of second doped semiconductor portions specifically includes:

[0033] A first material layer and a first doped semiconductor material layer are formed on the first surface;

[0034] The first material layer and the first doped semiconductor material layer are patterned to form a passivation portion and a first doped semiconductor portion;

[0035] A solid second material layer and a second doped semiconductor material layer are formed on one side of the first surface of the substrate;

[0036] The second material layer and the second doped semiconductor material layer are patterned to form the second doped semiconductor portion.

[0037] In one embodiment, the passivation portion and the second doped semiconductor portion are formed in the same step; the step of forming the passivation portion, the plurality of first doped semiconductor portions, and the plurality of second doped semiconductor portions specifically includes:

[0038] A first doped semiconductor portion is formed on the first surface of the substrate;

[0039] A solid second material layer and a second doped semiconductor material layer are formed on one side of the first surface of the substrate;

[0040] The second material layer and the second doped semiconductor material layer are patterned to form a passivation portion and a second doped semiconductor portion.

[0041] In one embodiment, the first doped semiconductor portion includes a first film layer and a first doped semiconductor layer stacked on top of each other; the second doped semiconductor portion includes a second film layer and a second doped semiconductor layer stacked on top of each other.

[0042] The first and second films are tunneling layers, and the first and second doped semiconductor layers are polysilicon-doped conductive layers; or

[0043] The first and second films are intrinsic amorphous silicon layers, and the first and second doped semiconductor layers are doped amorphous silicon layers.

[0044] In one embodiment, after the step of forming a passivation portion, a plurality of first doped semiconductor portions, and a plurality of second doped semiconductor portions on the first surface, the method further includes:

[0045] Cut along the thickness direction of the substrate to form at least two back-contact solar cells.

[0046] In one embodiment, the passivation portion is also partially formed in a region of the first surface located inside the edge region;

[0047] In the step of cutting along the thickness direction of the substrate, the cutting is performed at a position inside the edge region where the passivation portion is located.

[0048] The aforementioned back-contact solar cells, their manufacturing methods, back-contact solar cell wafers, and the beneficial effects of photovoltaic modules are as follows:

[0049] By providing a passivation portion in the edge region of the first surface of the substrate, which is adjacent to the side of the substrate, the passivation portion can passivate the edge region of the substrate, reduce edge recombination on the edge surface of the back contact solar cell, and thus improve the efficiency of the back contact solar cell. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of a back-contact solar cell provided in an embodiment of this application;

[0051] Figure 2 Another schematic diagram of a back-contact solar cell provided in an embodiment of this application;

[0052] Figure 3 A schematic diagram of another structure of the back-contact solar cell provided in the embodiments of this application;

[0053] Figure 4This is a schematic diagram of the structure of the back-contact solar cell mother sheet provided in the embodiments of this application;

[0054] Figure 5 A flowchart illustrating a method for fabricating a back-contact solar cell according to an embodiment of this application;

[0055] Figure 6 A schematic diagram illustrating the formation of a second mask layer in the fabrication method of a back-contact solar cell provided in this application embodiment;

[0056] Figure 7 A schematic diagram illustrating the formation of a passivation portion in a method for fabricating a back-contact solar cell according to an embodiment of this application;

[0057] Figure 8 This is a schematic diagram illustrating the cutting process in the fabrication method of the back-contact solar cell provided in this application embodiment.

[0058] Explanation of icon numbers:

[0059] 100. Back-contact solar cell;

[0060] 10. Substrate; 20. First doped semiconductor section; 21. First electrode; 30. Second doped semiconductor section; 301. Second material layer; 302. Second doped semiconductor material layer; 31. Second electrode; 41. First mask layer; 42. Second mask layer; 50. Passivation section; 51. First portion; 52. Second portion;

[0061] F, First surface; C, Side surface; B, Edge region; Y1, First preset direction; Y2, Second preset direction; J, Boundary position;

[0062] 200. Back contact solar cell mother plate. Detailed Implementation

[0063] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0064] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0068] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0069] The following description, in conjunction with the accompanying drawings, illustrates the back-contact solar cell and its fabrication method, the back-contact solar cell mother wafer, and the photovoltaic module according to embodiments of this application. It should be noted that this application uses a TBC (Total Cell Charge) back-contact solar cell as an example for illustration. However, the back-contact solar cell can also be configured as other types of cells, such as HBC (Hybrid Cell Charge) solar cells, depending on actual needs. The same principle applies to other types of back-contact solar cells, and will not be elaborated upon here.

[0070] Figure 1 This is a schematic diagram of the structure of a back-contact solar cell provided in an embodiment of this application; Figure 2 Another schematic diagram of a back-contact solar cell provided in an embodiment of this application; Figure 3 A schematic diagram of another structure of the back-contact solar cell provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the back-contact solar cell mother sheet provided in the embodiments of this application.

[0071] Reference Figure 1 and Figure 2 The present application provides a back contact solar cell 100 including a substrate 10, a plurality of first doped semiconductor portions 20 and a plurality of second doped semiconductor portions 30, a first electrode 21 and a second electrode 31, and a passivation portion 50.

[0072] The substrate 10 includes a first surface F and a plurality of side surfaces C adjacent to the first surface F, the first surface F including an edge region B adjacent to the side surfaces C.

[0073] Multiple first-doped semiconductor portions 20 and multiple second-doped semiconductor portions 30 are alternately and spaced apart along a first predetermined direction Y1 on the first surface F. The first-doped semiconductor portions 20 and the second-doped semiconductor portions 30 have opposite doping types and are insulated from each other. A first electrode 21 is electrically connected to the first-doped semiconductor portion 20, and a second electrode 31 is electrically connected to the second-doped semiconductor portion 30.

[0074] The passivation portion 50 is disposed in the edge region B and is insulated from the first doped semiconductor portion 20 and the second doped semiconductor portion 30. Exemplarily, the passivation portion 50 directly covers the edge region B of the first surface F.

[0075] By providing a passivation portion 50 on the edge region B of the first surface F of the substrate 10, and the edge region B being adjacent to the side surface C of the substrate 10, the passivation portion 50 can passivate the edge region B of the substrate 10, thereby reducing edge recombination on the edge surface of the back contact solar cell 100 and improving the efficiency of the back contact solar cell 100.

[0076] The first surface F can be, for example, the back surface of the back-contact solar cell 100. Multiple side surfaces C are adjacent to the first surface F, and these side surfaces C can correspond to the edge surfaces of the back-contact solar cell 100. An edge region B is adjacent to a side surface C, meaning that the edge region B is the portion of the first surface F closest to the side surface C. Furthermore, there can be sufficient spacing between the first doped semiconductor portion 20 and the second doped semiconductor portion 30 to ensure insulation between them.

[0077] The first electrode 21 is electrically connected to the first doped semiconductor section 20, and the second electrode 31 is electrically connected to the second doped semiconductor section 30. Figure 1 The example shown is a back-contact solar cell 100 without a main grid structure. Both the first electrode 21 and the second electrode 31 include multiple fine grids spaced apart along the first preset direction Y1, extending in a direction perpendicular to the first preset direction Y1. Furthermore, the direction perpendicular to the first preset direction Y1 is defined as the second preset direction Y2. Both the first preset direction Y1 and the second preset direction Y2 are parallel to the first surface F. Of course, this application is not limited to this; the first electrode 21 and the second electrode 31 may also include both fine grids and a main grid, and the patterns of the fine grids and the main grid can be set according to actual needs. Figure 1 The gateless structure is just one example of the first electrode 21 and the second electrode 31.

[0078] In this embodiment, the first doped semiconductor section 20, the second doped semiconductor section 30, and the passivation section 50 each include a first doped semiconductor layer, a second doped semiconductor layer, and a third doped semiconductor layer, respectively. Specifically, the first doped semiconductor section 20 includes a first doped semiconductor layer, the second doped semiconductor section 30 includes a second doped semiconductor layer, and the passivation section 50 includes a third doped semiconductor layer. The doping type of the third doped semiconductor layer is the same as that of the first or second doped semiconductor layer.

[0079] In some embodiments, the doping type of the third doped semiconductor layer can be the same as that of the substrate 10, which facilitates improved carrier collection efficiency compared to the case where the doping type is opposite to that of the substrate 10. Furthermore, the doping concentration of the third doped semiconductor layer can be greater than that of the substrate 10.

[0080] Furthermore, the passivation portion 50 has the same film structure as the first doped semiconductor portion 20 or the second doped semiconductor portion 30. In this way, the passivation portion 50 can be fabricated simultaneously during the fabrication of the first doped semiconductor portion 20 or the second doped semiconductor portion 30, which can save process steps and reduce costs.

[0081] It is understood that the passivation section 50 and the first doped semiconductor section 20 have the same film structure, meaning that each film layer in the passivation section 50 corresponds one-to-one with each film layer in the first doped semiconductor section 20 and the number of films is the same. Furthermore, the film layer type and material of the corresponding film layers in the passivation section 50 and the first doped semiconductor section 20 are completely identical. Similarly, the passivation section 50 and the second doped semiconductor section 30 have the same film structure, meaning that each film layer in the passivation section 50 corresponds one-to-one with each film layer in the second doped semiconductor section 30 and the number of films is the same. Furthermore, the film layer type and material of the corresponding film layers in the passivation section 50 and the second doped semiconductor section 30 are completely identical.

[0082] In some embodiments, the doping type of the third doped semiconductor layer is the same as that of the first doped semiconductor layer, and the minimum spacing between the passivation portion 50 and any of the second doped semiconductor portions 30 is greater than 50 micrometers.

[0083] Alternatively, the doping type of the third doped semiconductor layer is the same as that of the second doped semiconductor layer, and the minimum spacing between the passivation portion 50 and any of the first doped semiconductor portions 20 is greater than 50 micrometers.

[0084] This configuration can prevent leakage between the passivation portion 50 and the first doped semiconductor portion 20 or the second doped semiconductor portion 30.

[0085] For example, in Figure 1 In the example, the passivation portion 50 is frame-shaped and includes two first portions 51 extending along a first preset direction Y1 and two second portions 52 extending along a second preset direction Y2. When the doping type of the third doped semiconductor layer is the same as that of the second doped semiconductor layer, the minimum distance between the passivation portion 50 and any of the first doped semiconductor portions 20 is greater than 50 micrometers. Specifically, the minimum distance between the first portion 51 and the end of each first doped semiconductor portion 20 is greater than 50 micrometers, and the second portion 52 is parallel to the first doped semiconductor portion 20 closest to the second portion 52, with a distance between them greater than 50 micrometers.

[0086] The doping type of the third doped semiconductor layer is the same as that of the first doped semiconductor layer. The case where the minimum spacing between the passivation portion 50 and any second doped semiconductor portion 30 is greater than 50 micrometers is similar and will not be described again here.

[0087] In this embodiment, the passivation portion 50 extends along at least a portion of the outer contour line of the first surface F and is configured as a continuous or discontinuous structure.

[0088] In some examples, refer to Figure 1 As shown, the passivation portion 50 extends along the entire outer contour of the first surface F. In some other examples, such as reference... Figure 3 As shown, the passivation portion 50 can extend along a portion of the outer contour line of the first surface F. Additionally, in Figure 1 and Figure 3 In the examples, the passivation portion 50 is constructed as a continuous structure. Of course, it can also be a discontinuous structure in which the passivation portion 50 is partially disconnected.

[0089] In some embodiments, refer to Figure 1 The passivation portion 50 is constructed as a frame-like structure that extends continuously along the outer contour line of the first surface F. This results in better passivation of each edge of the substrate 10.

[0090] exist Figure 1 In the example, the outer edge of the passivation portion 50 coincides with the outer contour line of the first surface F. This ensures that the passivation portion 50 completely covers the outer contour edge of the first surface F of the substrate 10, resulting in a better reduction of edge recombination.

[0091] Alternatively, the outer edge of the passivation portion 50 may have a gap with the outer contour line of the first surface F. For example, the gap between the outer edge of the passivation portion 50 and the outer contour line of the first surface F needs to be less than 20 micrometers to ensure that edge colliding is minimized.

[0092] In this embodiment of the application, combined with Figure 1 and Figure 2 The first surface F extends continuously inward along its outer contour line, defining a frame-shaped edge region B. The minimum width d1 of the edge region B along the first direction is greater than 500 micrometers. This makes it less likely for misalignment to occur during the printing of the first electrode 21 and the second electrode 31. The first direction is parallel to the first surface F and extends inward from the outer contour line of the first surface F.

[0093] Furthermore, the width d2 of the passivation portion 50 along the first direction is 200 micrometers to 500 micrometers. For example, the width of the passivation portion 50 along the first direction is 200 micrometers to 300 micrometers, thus preventing the mask from sticking to the screen during the fabrication of the passivation portion 50 using a masking method. In some other embodiments, the width of the passivation portion 50 along the first direction may also be 400 micrometers to 500 micrometers.

[0094] In this embodiment, the back-contact solar cell 100 further includes a first passivation layer. The first passivation layer is disposed on the surface of the first doped semiconductor portion 20 and the second doped semiconductor portion 30 away from the substrate 10, and covers the passivation portion 50. Here, the material of the first passivation layer can be a single or composite thin film of silicon nitride, aluminum oxide, titanium oxide, silicon oxide, silicon oxynitride, etc. It serves to passivate the first surface F (e.g., the back surface) of the back-contact solar cell 100. In some embodiments, the first passivation layer can also serve to reduce reflection.

[0095] The first electrode 21 and the second electrode 31 are disposed on the first passivation layer and penetrate the first passivation layer, so as to be electrically connected to the first doped semiconductor section 20 and the second doped semiconductor section 30, respectively.

[0096] In some embodiments, the first doped semiconductor layer in the first doped semiconductor section 20 may be a first doped polysilicon layer, and the second doped semiconductor layer in the second doped semiconductor section 30 may be a second doped polysilicon layer. The third doped semiconductor layer in the passivation section 50 may be either a first doped polysilicon layer or a second doped polysilicon layer.

[0097] Specifically, the first doped semiconductor section 20 includes a first tunneling oxide layer and a first doped polysilicon layer stacked on the first surface F, and the second doped semiconductor section 30 includes a second tunneling oxide layer and a second doped polysilicon layer stacked on the first surface F. The passivation section 50 includes a first film layer and a second film layer (a third doped semiconductor layer) sequentially stacked on the first surface F. The first film layer and the second tunneling oxide layer are made of the same material, and the second film layer and the second doped polysilicon layer are made of the same material. Alternatively, in some other embodiments, the first film layer and the first tunneling oxide layer are made of the same material, and the second film layer and the first doped polysilicon layer are made of the same material.

[0098] In some other embodiments, when the back contact solar cell 100 is an HBC cell, the first doped semiconductor portion 20 can be first doped amorphous silicon or first doped microcrystalline silicon, and the second doped semiconductor portion 30 can be second doped amorphous silicon or second doped microcrystalline silicon. Thus, the third doped semiconductor layer in the third passivation portion 50 can be first doped amorphous silicon or first doped microcrystalline silicon. Alternatively, the third doped semiconductor layer in the third passivation portion 50 can be second doped amorphous silicon or second doped microcrystalline silicon.

[0099] Reference Figure 4 This application embodiment also provides a back-contact solar cell mother wafer 200, including at least two of the above-described back-contact solar cells 100, with the corresponding side edges of adjacent back-contact solar cells connected to each other to form an integral structure.

[0100] Thus, the aforementioned back-contact solar cell 100 can be formed by cutting the back-contact solar cell mother wafer 200. Furthermore, the connection of corresponding side edges of adjacent back-contact solar cells 100 to form an integrated structure specifically means that, before cutting, multiple back-contact solar cells 100 are formed integrally, and the corresponding film layers in each back-contact solar cell are formed in the same process.

[0101] Here, the corresponding side edge refers to the side edge used to join two back-contact solar cells 100 together. For example, for two square back-contact solar cells 100 in top view, one side of one back-contact solar cell 100 is connected to one side of the other back-contact solar cell 100 to form a back-contact solar cell mother wafer 200. In this case, these two side lengths are the corresponding side edges of the two back-contact solar cells 100. When there are more back-contact solar cells 100 adjacent to each other, there is at least one set of the above-mentioned corresponding side edges between each pair of adjacent back-contact solar cells 100.

[0102] Furthermore, passivation portions 50 are provided on corresponding side edges of adjacent back-contact solar cells 100, and the passivation portions 50 on corresponding side edges of adjacent back-contact solar cells 100 are connected to each other to form a continuous pattern. For example, the back-contact solar cell mother wafer 200 includes two back-contact solar cells, and the corresponding passivation portions 50 of the two back-contact solar cells 100 are connected to each other to form a continuous pattern.

[0103] With this configuration, the cutting position of the back contact solar cell mother wafer 200 is actually located at the junction J of the two passivation portions 50, i.e. Figure 4 As shown by the dashed lines, in the back-contact solar cell 100 formed by such slicing, the passivation portion 50 can cover the entire outer edge of the outer contour line of the first surface F. That is, there is no gap between the passivation portion 50 and the outer edge of the outer contour line of the first surface F. This further reduces the cell efficiency loss caused by slicing.

[0104] In some other embodiments, the corresponding side edges of adjacent back-contact solar cells 100 may not be provided with passivation portions 50, that is, the corresponding side edges forming an integral structure may not be provided with passivation portions, so that the cutting position of the back-contact solar cell mother sheet 200 is located at the position where no passivation portion 50 is provided.

[0105] Figure 5 A flowchart illustrating a method for fabricating a back-contact solar cell according to an embodiment of this application; Figure 6 A schematic diagram illustrating the formation of a second mask layer in the fabrication method of a back-contact solar cell provided in this application embodiment; Figure 7A schematic diagram illustrating the formation of a passivation portion in a method for fabricating a back-contact solar cell according to an embodiment of this application; Figure 8 This is a schematic diagram illustrating the cutting process in the fabrication method of the back-contact solar cell provided in this application embodiment.

[0106] Reference Figure 1 , Figure 5 , Figure 6 , Figure 7 This application also provides a method for manufacturing a back-contact solar cell, the method comprising:

[0107] S10. A substrate 10 is provided, the substrate 10 including a first surface F and a plurality of side surfaces C adjacent to the first surface F, the first surface F including an edge region B adjacent to the side surfaces C.

[0108] S20, a passivation portion 50, a plurality of first doped semiconductor portions 20 and a plurality of second doped semiconductor portions 30 are formed on the first surface F. The passivation portion 50 is located in the edge region B and is insulated from the first doped semiconductor portions 20 and the second doped semiconductor portions 30. The doping types of the first doped semiconductor portions 20 and the second doped semiconductor portions 30 are opposite and they are insulated from each other.

[0109] S30. A first electrode 21 and a second electrode 31 are formed on one side of the first surface F of the substrate 10. The first electrode 21 is electrically connected to the first doped semiconductor portion 20, and the second electrode 31 is electrically connected to the second doped semiconductor portion 30.

[0110] By forming a passivation portion 50 on the edge region B of the first surface F of the substrate 10, and the edge region B being adjacent to the side surface C of the substrate 10, the passivation portion 50 can passivate the edge region B of the substrate 10, reducing edge recombination on the edge surface of the back contact solar cell 100, thereby improving the efficiency of the back contact solar cell 100. In this embodiment, the first doped semiconductor portion 20 is P-type doped and the second doped semiconductor portion 30 is N-type doped as an example for explanation, but this application is not limited to this, and the first doped semiconductor portion 20 may also be N-type doped and the second doped semiconductor portion 30 may be P-type doped.

[0111] In this embodiment, the first doped semiconductor section 20 includes a first film layer and a first doped semiconductor layer stacked on top of each other. The second doped semiconductor section 30 includes a second film layer and a second doped semiconductor layer stacked on top of each other.

[0112] The back-contact solar cell 100 can be a TBC cell or an HBC cell. When the back-contact solar cell 100 is a TBC cell, the first and second films are tunneling layers, and the first and second doped semiconductor layers are polycrystalline silicon doped conductive layers. When the back-contact solar cell 100 is an HBC cell, the first and second films are intrinsic amorphous silicon layers, and the first and second doped semiconductor layers are doped amorphous silicon layers.

[0113] When the back-contact solar cell 100 is a TBC cell, before forming the first electrode 21 and the second electrode 31, a first passivation layer (not shown) is formed on the surface of the first doped semiconductor portion 20 and the second doped semiconductor portion 30 away from the substrate 10. The first passivation layer also covers the passivation portion 50. In this way, the first electrode 21 and the second electrode 31 can be formed on the first passivation layer and penetrate through the first passivation layer during the formation process, so that the first electrode 21 is electrically connected to the first doped semiconductor portion 20 and the second electrode 31 is electrically connected to the second doped semiconductor portion 30.

[0114] In this embodiment, the passivation portion 50 is formed in the same step as either the first doped semiconductor portion 20 or the second doped semiconductor portion 30. This allows the passivation portion 50 to be fabricated simultaneously with the fabrication of either the first doped semiconductor portion 20 or the second doped semiconductor portion 30, saving process steps and reducing costs.

[0115] In this embodiment of the application, combined with Figure 1 , Figure 6 and Figure 7 When the passivation portion 50 and the second doped semiconductor portion 30 are formed in the same step, the steps of forming the passivation portion 50, the plurality of first doped semiconductor portions 20, and the plurality of second doped semiconductor portions 30 specifically include:

[0116] A first doped semiconductor portion 20 is formed on the first surface F of the substrate 10. The first doped semiconductor portion 20 may, for example, be formed in a region inside the edge region B.

[0117] A second material layer 301 and a second doped semiconductor material layer 302 are formed on one side of the first surface F of the substrate 10.

[0118] The second material layer 301 and the second doped semiconductor material layer 302 are patterned to form a passivation portion 50 and a second doped semiconductor portion 30.

[0119] For example, the step of forming the first doped semiconductor portion 20 may include:

[0120] A first material layer and a first doped semiconductor material layer (not shown) are formed on the first surface F. A patterned first mask layer 41 is formed on the first doped semiconductor material layer, and the areas of the first material layer and the first doped semiconductor material layer not covered by the first mask layer 41 are etched away to form the first doped semiconductor portion 20.

[0121] Furthermore, before patterning the second material layer 301 and the second doped semiconductor material layer 302, a patterned second mask layer 42 needs to be formed on the second doped semiconductor material layer 302. In this way, the area of ​​the second doped semiconductor material layer 302 not covered by the second mask layer 42 is etched away, thereby forming a passivation portion 50 in the portion of the second doped semiconductor material layer 302 and the second material layer 301 located under the second mask layer 42, and forming a plurality of second doped semiconductor portions 30 in the portion located inside the edge region B.

[0122] In this embodiment of the application, when the passivation portion 50 and the first doped semiconductor portion 20 are formed in the same step, the steps of forming the passivation portion 50, the plurality of first doped semiconductor portions 20, and the plurality of second doped semiconductor portions 30 specifically include:

[0123] A first material layer and a first doped semiconductor material layer (not shown) are formed on the first surface F.

[0124] The first material layer and the first doped semiconductor material layer are patterned to form a passivation portion 50 and a first doped semiconductor portion 20. Unlike the previous embodiment, the first mask layer 41 needs to cover the area on the first surface F where the passivation portion 50 and the first doped semiconductor portion 20 will be formed. During the etching process of the first doped semiconductor material layer and the first material layer using the first mask layer 41, in the area of ​​the first doped semiconductor material layer and the first material layer covered by the first mask layer 41, the portion located at the edge region B forms the passivation portion 50, and the region located inside the edge region B forms the first doped semiconductor portion 20.

[0125] After the passivation portion 50 and the first doped semiconductor portion 20 are formed, a second material layer 301 and a second doped semiconductor material layer 302 are formed on the first surface F side of the substrate 10.

[0126] The second material layer 301 and the second doped semiconductor material layer 302 are patterned to form the second doped semiconductor portion 30. Unlike the previous embodiment, the second mask layer 42 only covers the area where the second doped semiconductor portion 30 will be formed.

[0127] Understandably, to improve efficiency, photovoltaic modules can be packaged using half-cell or multi-cell technology. This involves cutting standard-sized cells in half or into multiple segments, and then connecting them in series to form a module.

[0128] In the method for fabricating a back-contact solar cell according to the embodiments of this application, the cutting step can be set at different locations. For example, it can be set after the first electrode 21 and the second electrode 31 are formed, or it can be set after the step of forming the passivation portion 50, the plurality of first doped semiconductor portions 20 and the plurality of second doped semiconductor portions 30 on the first surface F.

[0129] In some embodiments, after the step of forming the passivation portion 50, the plurality of first doped semiconductor portions 20, and the plurality of second doped semiconductor portions 30 on the first surface F, the following is further included:

[0130] Cut along the thickness direction of the substrate 10 to form at least two back-contact solar cells 100.

[0131] Reference Figure 8 For example, the passivation portion 50 is also partially formed in the region of the first surface F located inside the edge region B.

[0132] In the step of cutting along the thickness direction of the substrate 10, the cut is made at a position where the passivation portion 50 is located inside the edge region B. For example, along... Figure 8 The single-dot dashed line positions are used to cut the back contact solar cells 100 in half. Each cut position is located on the passivation portion 50 and can be parallel to a portion of the edge of the passivation portion 50.

[0133] The following describes a specific example of a method for fabricating a back-contact solar cell according to an embodiment of this application. The method includes:

[0134] Step 1, refer to Figure 6 A first material layer and a first doped semiconductor material layer (not shown) are formed on the first surface F. A patterned first mask layer 41 is formed on the first doped semiconductor material layer, and the areas of the first material layer and the first doped semiconductor material layer not covered by the first mask layer 41 are etched away to form the first doped semiconductor portion 20.

[0135] Step 2, continue to refer to Figure 6 A second material layer 301 and a second doped semiconductor material layer 302 are formed on one side of the first surface F of the substrate 10.

[0136] Step 3, Combining Figure 6 and Figure 7A patterned second mask layer 42 is formed on the second doped semiconductor material layer 302. In this way, the area of ​​the second doped semiconductor material layer 302 not covered by the second mask layer 42 is etched away. As a result, in the second doped semiconductor material layer 302 and the second material layer 301 located under the second mask layer 42, a passivation portion 50 is formed in the edge region B, and a plurality of second doped semiconductor portions 30 are formed in the portion located inside the edge region B.

[0137] Step 4, Combining Figure 1 and Figure 7 A first passivation layer (not shown) is formed on the surface of the first doped semiconductor portion 20, the second doped semiconductor portion 30, and the passivation portion 50 away from the substrate 10. A first electrode 21 and a second electrode 31 are formed on the first passivation layer, penetrating the first passivation layer, and the first electrode 21 is electrically connected to the first doped semiconductor portion 20, and the second electrode 31 is electrically connected to the second doped semiconductor portion 30.

[0138] Here, steps 1-4 above are explained using a TBC cell as an example of a back-contact solar cell. The case of an HBC cell as a back-contact solar cell is similar and will not be repeated here.

[0139] This application also provides a photovoltaic module and a photovoltaic system. The photovoltaic module includes at least one battery string, and the battery string includes at least two back-contact solar cells 100 as described above, which can be connected together by string welding.

[0140] A photovoltaic (PV) system includes the aforementioned PV modules. PV systems can be applied in PV power plants, such as ground-mounted, rooftop, and floating power plants, as well as in equipment or devices that utilize solar energy for power generation, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understood that the application scenarios for PV systems are not limited to these; that is, PV systems can be applied in all areas that require solar energy for power generation. Taking a PV power grid as an example, a PV system can include PV arrays, combiner boxes, and inverters. A PV array can be an array combination of multiple PV modules; for example, multiple PV modules can form multiple PV arrays. The PV arrays are connected to combiner boxes, which collect the current generated by the PV arrays. The collected current flows through an inverter, converts it into AC power required by the mains grid, and then connects to the mains grid to achieve solar power supply.

[0141] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0142] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A back-contact solar cell, characterized in that, include: The substrate includes a first surface and a plurality of side surfaces adjacent to the first surface, the first surface including edge regions adjacent to the side surfaces; Multiple first-doped semiconductor portions and multiple second-doped semiconductor portions are arranged alternately and at intervals on the first surface along a first preset direction, wherein the first-doped semiconductor portions and the second-doped semiconductor portions have opposite doping types and are insulated from each other; A first electrode and a second electrode, wherein the first electrode is electrically connected to the first doped semiconductor portion and the second electrode is electrically connected to the second doped semiconductor portion; as well as The passivation portion is disposed in the edge region and is insulated from the first doped semiconductor portion and the second doped semiconductor portion.

2. The back-contact solar cell according to claim 1, characterized in that, The first doped semiconductor portion includes a first doped semiconductor layer, the second doped semiconductor portion includes a second doped semiconductor layer, and the passivation portion includes a third doped semiconductor layer; The doping type of the third doped semiconductor layer is the same as that of the first doped semiconductor layer or the second doped semiconductor layer.

3. The back-contact solar cell according to claim 2, characterized in that, The passivation portion has the same film structure as the first doped semiconductor portion or the second doped semiconductor portion.

4. The back-contact solar cell according to claim 2, characterized in that, The doping type of the third doped semiconductor layer is the same as that of the first doped semiconductor layer, and the minimum spacing between the passivation portion and any of the second doped semiconductor portions is greater than 50 micrometers; or The doping type of the third doped semiconductor layer is the same as that of the second doped semiconductor layer, and the minimum distance between the passivation portion and any of the first doped semiconductor portions is greater than 50 micrometers.

5. The back-contact solar cell according to claim 1, characterized in that, The passivation portion extends along at least a portion of the outer contour line of the first surface and is configured as a continuous or discontinuous structure.

6. The back-contact solar cell according to claim 5, characterized in that, The passivation portion is constructed as a frame-like structure that extends continuously along the outer contour line of the first surface.

7. The back-contact solar cell according to claim 6, characterized in that, The outer edge of the passivation portion coincides with the outer contour line of the first surface; Alternatively, the distance between the outer edge of the passivation portion and the outer contour line of the first surface is less than 20 micrometers.

8. The back-contact solar cell according to claim 1, characterized in that, The first surface extends inward along its outer contour line to define a frame-shaped edge region. The edge region has a minimum width of more than 500 micrometers along a first direction, wherein the first direction is parallel to the first surface and is an inward direction from the outer contour line of the first surface.

9. The back-contact solar cell according to claim 8, characterized in that, The passivation portion has a width of 200 micrometers to 500 micrometers along the first direction.

10. The back-contact solar cell according to claim 1, characterized in that, The back contact solar cell also includes a first passivation layer; The first passivation layer is disposed on the surfaces of the first doped semiconductor portion and the second doped semiconductor portion opposite to the substrate, and covers the passivation portion; The first electrode and the second electrode are disposed on the first passivation layer and penetrate the first passivation layer, so as to be electrically connected to the first doped semiconductor portion and the second doped semiconductor portion, respectively.

11. A back-contact solar cell mother plate, characterized in that, It includes at least two back-contact solar cells as described in any one of claims 1-10, with the corresponding side edges of adjacent back-contact solar cells connected to each other to form an integral structure.

12. The back-contact solar cell mother wafer according to claim 11, characterized in that, The passivation portion is provided on the corresponding side edge of each of the adjacent back contact solar cells, and the passivation portions on the corresponding side edge of the adjacent back contact solar cells are connected to each other to form a continuous pattern; or The passivation portion is not provided on the corresponding side edges that form the integral structure.

13. A photovoltaic module, characterized in that, It includes at least one battery string, the battery string comprising at least two back-contact solar cells as claimed in any one of claims 1-10.

14. A method for manufacturing a back-contact solar cell, characterized in that, include: A substrate is provided, the substrate including a first surface and a plurality of side surfaces adjacent to the first surface, the first surface including an edge region adjacent to the side surfaces; A passivation portion, a plurality of first doped semiconductor portions, and a plurality of second doped semiconductor portions are formed on the first surface. The passivation portion is located in the edge region and is insulated from the first doped semiconductor portions and the second doped semiconductor portions. The first doped semiconductor portions and the second doped semiconductor portions have opposite doping types and are insulated from each other. A first electrode and a second electrode are formed on one side of the first surface of the substrate. The first electrode is electrically connected to the first doped semiconductor portion, and the second electrode is electrically connected to the second doped semiconductor portion.

15. The method for manufacturing a back-contact solar cell according to claim 14, characterized in that, The passivation portion is formed in the same step as either the first doped semiconductor portion or the second doped semiconductor portion.

16. The method for manufacturing a back-contact solar cell according to claim 15, characterized in that, The passivation portion and the first doped semiconductor portion are formed in the same step; the step of forming the passivation portion, the plurality of first doped semiconductor portions, and the plurality of second doped semiconductor portions specifically includes: A first material layer and a first doped semiconductor material layer are formed on the first surface; The first material layer and the first doped semiconductor material layer are patterned to form the passivation portion and the first doped semiconductor portion; A solid second material layer and a second doped semiconductor material layer are formed on one side of the first surface of the substrate; The second material layer and the second doped semiconductor material layer are patterned to form the second doped semiconductor portion.

17. The method for manufacturing a back-contact solar cell according to claim 15, characterized in that, The passivation portion and the second doped semiconductor portion are formed in the same step; the step of forming the passivation portion, the plurality of first doped semiconductor portions, and the plurality of second doped semiconductor portions specifically includes: A first doped semiconductor portion is formed on the first surface of the substrate; A solid second material layer and a second doped semiconductor material layer are formed on one side of the first surface of the substrate; The second material layer and the second doped semiconductor material layer are patterned to form the passivation portion and the second doped semiconductor portion.

18. The method for manufacturing a back-contact solar cell according to claim 14, characterized in that, The first doped semiconductor portion includes a first film layer and a first doped semiconductor layer stacked on top of each other; the second doped semiconductor portion includes a second film layer and a second doped semiconductor layer stacked on top of each other; The first film layer and the second film layer are tunneling layers, and the first doped semiconductor layer and the second doped semiconductor layer are polysilicon doped conductive layers; or The first film layer and the second film layer are intrinsic amorphous silicon layers, and the first doped semiconductor layer and the second doped semiconductor layer are doped amorphous silicon layers.

19. A method for manufacturing a back-contact solar cell according to any one of claims 14-18, characterized in that, After the step of forming a passivation portion, a plurality of first doped semiconductor portions, and a plurality of second doped semiconductor portions on the first surface, the method further includes: The substrate is cut along its thickness direction to form at least two back-contact solar cells.

20. The method for manufacturing a back-contact solar cell according to claim 19, characterized in that, The passivation portion is also partially formed in the region located inside the edge region of the first surface; In the step of cutting along the thickness direction of the substrate, the cutting is performed at a position inside the edge region where the passivation portion is located.

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