Solar cell and photovoltaic module

Abstract

The application relates to the field of solar cells, and particularly discloses a solar cell and a photovoltaic module. The solar cell comprises a silicon substrate, a patterned doped region located on the back light surface of the silicon substrate, the doped region comprising first doped regions and second doped regions in an interdigital distribution, an isolation region located on the back light surface of the silicon substrate, the isolation region being used for separating the first doped regions and the second doped regions, and a positioning mark structure located on the back light surface of the silicon substrate, the positioning mark structure being used as a positioning mark for pattern making. The positioning mark structure comprises a pattern mark part, the pattern mark part being arranged on the doped region and separating the doped region, and a first and a second isolation groove connected end to end, the isolation groove being arranged in a circumferential direction around the pattern mark part. In a first direction, the width of the isolation groove is D, the width of the isolation region is L1, D is greater than L1, and the first direction is the width direction of the isolation region.

Description

Technical Field

[0001] This application relates to the technical field of solar cells, and more particularly to a solar cell and photovoltaic module. Background Technology

[0002] Back-contact solar cells, as the mainstream direction for future high-efficiency solar cells, have the advantage of no grid lines obstructing the light-receiving surface, significantly improving optical utilization. However, transferring all positive and negative electrode grid lines to the back-lighting surface also presents challenges in fabricating regions with different polarities. To accurately construct the PN junction on the back-lighting surface, repeated mask deposition and laser delamination processes are required, which places extremely high demands on the accuracy of pattern positioning. The positioning marker structure (also known as the Mark point) serves as a positioning reference; poor recognition results can lead to camera positioning inaccuracies, causing problems with the cell structure and ultimately resulting in decreased cell performance or failure. Summary of the Invention

[0003] To improve the recognition effect and positioning accuracy of the positioning marker structure, this application provides a solar cell and photovoltaic module.

[0004] In a first aspect, embodiments of this application provide a solar cell.

[0005] A solar cell, comprising:

[0006] Silicon substrate;

[0007] The patterned doped regions are located on the back surface of the silicon substrate. The doped regions include a first doped region and a second doped region distributed in an interdigitated pattern. One of the first doped region and the second doped region is a P-type doped region and the other is an N-type doped region.

[0008] An isolation region is located on the back surface of the silicon substrate, and the isolation region is used to separate the first doped region and the second doped region;

[0009] A positioning mark structure is located on the back surface of the silicon substrate, and the positioning mark structure is used as a positioning mark for pattern making;

[0010] The positioning mark structure includes:

[0011] A graphic marking portion, wherein the graphic marking portion is disposed in the doped region and separates the doped region;

[0012] An isolation groove connected end to end, the isolation groove being arranged circumferentially around the graphic mark portion;

[0013] In a first direction, the width of the isolation groove is D, the width of the isolation area is L1, D is greater than L1, and the first direction is the width direction of the isolation area.

[0014] As an optional implementation, in the embodiments of this application, D is 1 μm to 200 μm larger than L1.

[0015] As an optional implementation, in the embodiments of this application, D is 11μm to 400μm, and L1 is 10μm to 200μm.

[0016] As an optional implementation, in the embodiments of this application, along the thickness direction of the silicon substrate, the orthographic projection outline of the graphic mark portion includes either a square or a rectangle, and the orthographic projection outer outline of the isolation groove includes either a square or a rectangle.

[0017] As an optional implementation, in the embodiments of this application, the isolation groove and the positioning mark portion are combined to form a U-shaped structure;

[0018] Along the first direction, the side length of the orthographic projection outer contour of the isolation groove is W1, the side length of the orthographic projection contour of the graphic mark is N1, and the ratio of N1 to W1 is (200~1000)∶(222~1800).

[0019] Along the second direction, the side length of the orthographic projection outer contour of the isolation groove is W2, the side length of the orthographic projection contour of the graphic mark is N2, the ratio of N2 to W2 is (200~1000)∶(222~1800), and the second direction is perpendicular to the first direction.

[0020] As an optional implementation, in the embodiments of this application, along the first direction, the width of the first doped region is L2, and the width of the second doped region is L3;

[0021] W1 is greater than at least one of L2 or L3.

[0022] As an optional implementation, in the embodiments of this application, W1 is 222μm to 1800μm, L2 is 200μm to 1000μm, and L3 is 200μm to 1000μm.

[0023] As an optional implementation, in an embodiment of this application, the graphic marker portion has a first side parallel to the second direction;

[0024] When the graphic mark is located in the first doped region, the first edge is aligned with the first side edge in the first doped region that is parallel to the second direction;

[0025] When the graphic mark is located in the second doped region, the first side is aligned with the second side of the second doped region that is parallel to the second direction.

[0026] As an optional implementation, in the embodiments of this application, when the patterned marking portion is located between the first doped regions, the film layer of the patterned marking portion is the same as the film layer of the second doped region;

[0027] When the patterned marking portion is located between the second doped regions, the composition of the patterned marking portion is the same as that of the film layer of the first doped region.

[0028] Secondly, embodiments of this application provide a photovoltaic module.

[0029] A photovoltaic module comprising a solar cell as described in the first aspect.

[0030] Compared with the prior art, the beneficial effects of this application are as follows:

[0031] This application provides a solar cell that significantly improves the camera's recognition and positioning accuracy during the pattern fabrication process by incorporating an improved positioning mark structure. Specifically, the central portion of the positioning mark structure is a graphic mark area, which reflects light to form a bright area; while the surrounding isolation groove is relatively darker than the graphic mark area. By capturing the contrast between the light and dark areas between the graphic mark area and the isolation groove, the camera can more accurately identify and position the positioning mark structure. Subsequent pattern fabrication processes use this positioning mark structure as a reference for laser etching or pattern printing.

[0032] By setting D to be greater than L1, meaning the width of the isolation groove is greater than the width of the isolation area, this width difference enhances the contrast between the isolation groove and the isolation area. This allows the camera to quickly distinguish the structural features of the positioning mark, achieving rapid and accurate positioning. It effectively avoids recognition errors caused by the similarity of features between the isolation groove and the isolation area, thus significantly improving the positioning accuracy of graphic creation.

[0033] Furthermore, setting the width of the isolation groove to be greater than the width of the isolation area helps optimize the continuity of the laser processing path, allowing a larger area to be covered in a single laser scan. This reduces the frequency of laser start-stop and jump, effectively controlling the heat accumulation effect in the laser processing area and suppressing the uneven edge contour problem caused by excessive heat accumulation during laser processing in traditional groove structures. Therefore, this application improves the accuracy and stability of laser processing, producing isolation grooves with uniform width and smooth edges, ensuring the dimensional accuracy and morphological regularity of the positioning mark structure. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure disclosed in the embodiments of this application, used to illustrate the first type of solar cell structure;

[0036] Figure 2 This is a top view of the positioning mark structure disclosed in the embodiments of this application, illustrating its position on the backlit surface.

[0037] Figure 3 This is a schematic diagram illustrating the structural size markings of the positioning markers disclosed in the embodiments of this application;

[0038] Figure 4 This is a photographic illustration of the positioning mark structure on the backlit surface, as disclosed in the embodiments of this application.

[0039] Figure 5 This is a schematic diagram of the structure disclosed in the embodiments of this application, used to illustrate the second type of solar cell structure.

[0040] Icons: 100, Solar cell; 1, Silicon substrate; 2, Doped region; 21, First doped region; 211, First side; 22, Second doped region; 221, Second side; 3, Isolation region; 4, Positioning mark structure; 41, Graphic mark part; 411, First edge; 42, Isolation groove; 51, First passivation layer; 52, Second passivation layer; 61, First electrode; 62, Second electrode; 71, First dielectric layer; 72, Second dielectric layer. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0043] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0044] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0045] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0046] The back surface of a solar cell contains an alternating structure of P-type and N-type doped regions, with an isolation zone between them. The positioning mark structure can be a groove structure formed directly by laser processing in either the P-type or N-type doped region. This groove structure is designed as a simple square or rectangular groove, and the laser processing directly ablates according to the preset shape and size. The width of this positioning mark structure is basically the same as the width of the isolation zone, making it difficult for the camera to distinguish the positioning mark structure from the isolation zone during recognition, thus affecting the accuracy of positioning. Furthermore, when forming the positioning mark structure by direct laser processing, the limitations of laser processing precision and potential issues such as jumps and stops during processing result in poor regularity of the edge contour shape of the positioning mark structure, further reducing the recognition effect of traditional positioning mark structures. This limits the accuracy and quality of cell pattern fabrication, ultimately affecting the overall performance and reliability of the solar cell.

[0047] To address these issues, this application proposes a solar cell that exhibits high camera recognition performance and positioning accuracy, effectively improving the image processing quality and performance of the solar cell.

[0048] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0049] In a first aspect, embodiments of this application provide a solar cell.

[0050] Reference Figure 1 A solar cell 100, comprising:

[0051] Silicon substrate 1;

[0052] The patterned doped region 2 is located on the back surface of the silicon substrate 1. The doped region 2 includes a first doped region 21 and a second doped region 22 distributed in an interdigitated pattern. One of the first doped region 21 and the second doped region 22 is a P-type doped region and the other is an N-type doped region.

[0053] Isolation region 3 is located on the back surface of silicon substrate 1 and is used to separate the first doped region 21 and the second doped region 22.

[0054] Combination Figure 2 As shown, the solar cell 100 also includes a positioning mark structure 4, which is located on the back surface of the silicon substrate 1 and serves as a positioning mark for pattern making.

[0055] The positioning marker structure 4 includes:

[0056] A graphic marking portion 41 is provided in the doped region 2 and separates the doped region 2;

[0057] The isolation grooves 42 are connected end to end and are arranged circumferentially around the graphic mark part 41.

[0058] Reference Figure 2 and Figure 3 In the first direction, the width of the isolation groove 42 is D, and the width of the isolation area 3 is L1, where D is greater than L1. The first direction is the width direction of the isolation area 3. Figure 2 and Figure 3 The X direction shown in the diagram is the first direction.

[0059] This application provides an improved positioning mark structure 4 in the solar cell 100, which significantly improves the camera's recognition effect and positioning accuracy of the positioning mark structure 4 during different pattern making processes. Specifically, the central part of the positioning mark structure 4 is a graphic mark part 41, which reflects light to form a bright area; while the isolation groove 42 surrounding the graphic mark part 41 is relatively darker than the graphic mark part 41. By capturing the light and dark contrast between the graphic mark part 41 and the isolation groove 42, the camera can more accurately identify and position the positioning mark structure 4. Subsequent pattern making processes use the positioning mark structure 4 as a reference for laser etching or pattern printing.

[0060] By setting D to be greater than L1, that is, the width of the isolation groove 42 is greater than the width of the isolation area 3. For example... Figure 4 As shown in the photograph of the positioning mark structure 4 on the backlit side of the silicon substrate 1, this width difference can enhance the contrast effect between the isolation groove 42 and the isolation area 3, enabling the camera to quickly distinguish the features of the positioning mark structure 4, achieve fast and accurate positioning, effectively avoid the recognition error problem caused by the similarity of features between the isolation groove 42 and the isolation area 3, and thus significantly improve the positioning accuracy of graphic production.

[0061] Furthermore, the wider isolation groove 42 than the isolation area 3 optimizes the continuity of the laser processing path, allowing a larger area to be covered in a single laser scan. This reduces the frequency of laser start-stop and jump, effectively controlling the heat accumulation effect in the laser processing area and suppressing the uneven edge contour problem caused by excessive heat accumulation during laser processing in traditional groove structures. Therefore, this application improves the accuracy and stability of laser processing, producing an isolation groove 42 with uniform width and smooth edges, ensuring the dimensional accuracy and morphological regularity of the positioning mark structure 4.

[0062] It should be noted that the P-type doping region is formed by doping polycrystalline silicon with trivalent elements (such as boron), creating a region in which holes are the majority carriers; the N-type doping region is formed by doping polycrystalline silicon with pentavalent elements (such as phosphorus, arsenic, etc.), creating a region in which electrons are the majority carriers.

[0063] In addition, such as Figure 1 As shown, on the back-light side of the silicon substrate 1, a first passivation layer 51 is disposed on the side of the doped region 2 opposite to the silicon substrate 1, while a second passivation layer 52 is disposed on the light-receiving side of the silicon substrate 1. The materials of the first passivation layer 51 and the second passivation layer 52 can be composed of passivation materials such as silicon nitride and silicon oxynitride. A first electrode 61 is disposed on the first doped region 21, and a second electrode 62 is disposed on the second doped region 22. The first electrode 61 and the second electrode 62 are silver electrodes. To better provide interface passivation for the silicon substrate 1, such as... Figure 5As shown, a first dielectric layer 71 may be disposed between the first doped region 21 and the silicon substrate 1, and a second dielectric layer 72 may be disposed between the second doped region 22 and the silicon substrate 1. The first dielectric layer 71 and the second dielectric layer 72 may include at least one of various dielectric materials, such as silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Preferably, the first dielectric layer 71 and the second dielectric layer 72 are silicon oxide layers.

[0064] In some embodiments, D is 1 μm to 200 μm larger than L1.

[0065] By limiting the range of the difference between the width D of the isolation groove 42 and the width L1 of the isolation area 3, it is beneficial to balance the camera's recognition effect and the space utilization on the backlight side of the silicon wafer. When the difference between D and L1 is too small, the contrast improvement effect between the isolation groove 42 and the isolation area 3 is still not significant enough. When the difference between D and L1 is too large, the isolation groove 42 occupies too much backlight area, increasing the loss of effective battery area.

[0066] For example, D is 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, or 60 μm larger than L1.

[0067] In some embodiments, D is 11 μm to 400 μm and L1 is 10 μm to 200 μm.

[0068] The dimensions of the isolation groove 42 width D and the isolation area 3 width L1 are controlled within the above-mentioned range, which can maintain a good contrast effect between the isolation groove 42 and the isolation area 3, and can also adapt to different battery sizes. For example, D can be 20μm, 50μm, 90μm, 140μm, 200μm, or 260μm, and L1 can be 10μm, 30μm, 60μm, 100μm, 150μm, or 200μm.

[0069] like Figure 2 As shown, in some embodiments, along the thickness direction of the silicon substrate 1, the orthographic projection outline of the graphic mark portion 41 includes any one of a square or a rectangle, and the orthographic projection outer outline of the isolation groove 42 includes any one of a square or a rectangle.

[0070] The orthographic projection contour of the graphic marker 41 and the orthographic projection outer contour of the isolation groove 42 both adopt regular geometric shapes such as squares or rectangles. This design simplifies the laser processing path and reduces the risk of processing deviations caused by path complexity. Furthermore, the regular geometric contour design enhances the precision control capability of laser processing, thereby reducing the contour forming error of the graphic marker 41 and the isolation groove 42. Simultaneously, the regular geometric contour provides a clear and stable feature reference for camera capture, which helps improve the overall positioning accuracy of the positioning mark structure 4 and enhances the positioning precision of the camera capture.

[0071] like Figure 2 and Figure 3 As shown, in some embodiments, the isolation groove 42 and the graphic mark portion 41 are combined to form a U-shaped structure;

[0072] Along the first direction, the side length of the orthographic projection of the outer contour of the isolation groove 42 is W1, the side length of the orthographic projection of the graphic mark part 41 is N1, and the ratio of N1 to W1 is (200~1000)∶(222~1800).

[0073] Along the second direction, the side length of the orthographic projection of the outer contour of the isolation groove 42 is W2, and the side length of the orthographic projection of the graphic mark portion 41 is N2. The ratio of N2 to W2 is (200~1000)∶(222~1800). The second direction is perpendicular to the first direction. Figure 2 and Figure 3 The Y-direction shown in the diagram is the second direction.

[0074] By defining the combination of the isolation groove 42 and the graphic mark part 41 to form a U-shaped structure, and controlling the dimensional ratio of the two directions, it is possible to better ensure that the positioning mark structure 4 forms a clear contrast between light and dark during camera capture, thereby further improving the accuracy of the entire positioning process. By limiting the ratio of N2 to W2 to (200~1000):(222~1800), a better contrast effect can be formed between the isolation groove 42 and the isolation area 3, improving the camera's recognition effect and accuracy of the positioning mark structure 4.

[0075] For example, N1 is 200 μm, N2 is 200 μm, W1 is 230 μm, and W2 is 230 μm; or N1 is 250 μm, N2 is 250 μm, W1 is 280 μm, and W2 is 280 μm.

[0076] Furthermore, the matching effect between the size setting of the positioning mark structure 4 and the size settings of the first doped region 21 and the second doped region 22 is also very important. The size settings of the first doped region 21 and the second doped region 22 will be further explained below.

[0077] like Figure 2 and Figure 3 As shown, in some embodiments, along the first direction, the width of the first doped region 21 is L2, and the width of the second doped region 22 is L3;

[0078] W1 is greater than at least one of L2 or L3.

[0079] When W1 is greater than at least one of L2 or L3, the isolation groove 42 exhibits a more pronounced difference in width compared to the surrounding doped region 2. This significant difference in width makes the positioning mark structure 4 more prominent on the backlight surface of the silicon substrate 1 during image capture and processing, reducing interference from the doped region 2 on the identification of the positioning mark structure 4, thereby further improving the camera's recognition accuracy and reliability of the positioning mark structure 4. Furthermore, by setting the width of the isolation groove 42 to be larger than the width of the doped region 2, the laser processing path can be optimized. During laser processing, a wider isolation groove 42 allows for a more continuous and smooth laser scanning path, reducing the number of laser start-stops and jumps. This helps reduce the heat accumulation effect caused by laser processing interruptions or discontinuities, thereby suppressing the generation of uneven edge contours, ensuring that the width of the isolation groove 42 is uniform and the edges are smooth, further improving the accuracy and stability of laser processing, and resulting in a positioning mark structure 4 with higher dimensional accuracy and more regular morphology.

[0080] In some embodiments, W1 is 222μm to 1800μm, L2 is 200μm to 1000μm, and L3 is 200μm to 1000μm.

[0081] From the perspective of camera recognition, the range setting of W1 ensures that the isolation groove 42 has a relatively obvious difference in width compared to the first doped region 21 and the second doped region 22. Since the lower limit of W1 is higher than the lower limits of L2 and L3, and the upper limit is also higher than the upper limits of L2 and L3, this ensures that the isolation groove 42 maintains sufficient width difference against the background of doped regions 2 of different sizes. This width difference allows the positioning mark structure 4 to form a clearer contrast with the surrounding first doped region 21 or second doped region 22 during image capture, thereby enhancing the camera's recognition accuracy of the positioning mark structure 4 and reducing recognition errors caused by similar sizes.

[0082] Furthermore, by controlling the size ratio of the isolation groove 42 to the graphic mark portion 41, further adjusting the sizes of the first doped region 21, the second doped region 22, and the isolation groove 42 can avoid excessive occupation of the limited space of the backlight surface of the silicon substrate 1 while ensuring the recognition effect of the positioning mark structure 4. This makes the overall battery design more compact, which is conducive to increasing the effective photoelectric conversion area of ​​the battery, thereby improving the photoelectric conversion efficiency of the battery.

[0083] It should be noted that different battery designs may have doped regions 2 of different widths. By setting W1 within the range of 222μm to 1800μm, various battery specifications can be adapted. During the production process, the size of W1 only needs to be adjusted according to the specific L2 and L3 values ​​to meet the positioning accuracy and space utilization requirements of different batteries, reducing the complexity of process adjustments and improving production efficiency.

[0084] For example, W1 is 230 μm, L2 is 200 μm, and L3 is 200 μm.

[0085] like Figure 2 As shown, in some embodiments, the graphic marker portion 41 has a first side 411 parallel to the second direction;

[0086] When the graphic mark portion 41 is located in the first doped region 21, the first side 411 is aligned with the first side 211 in the first doped region 21 that is parallel to the second direction.

[0087] When the pattern mark 41 is located in the second doped region 22, the first side 411 is aligned with the second side 221 in the second doped region 22 that is parallel to the second direction.

[0088] In laser processing, this alignment design helps optimize the processing path and improve processing accuracy. Since the first side 411 of the patterned marking portion 41 is aligned with the side edge of the corresponding doped region 2, laser processing can proceed along these aligned edges, resulting in smoother and more precise processing. This not only helps reduce deviations during laser processing but also ensures that the shape of the patterned marking portion 41 is more regular and its dimensional accuracy is higher. Furthermore, the aligned edges can reduce adjustment and calibration steps in laser processing, improving production efficiency.

[0089] like Figure 2 As shown, in some embodiments, when the patterned marking portion 41 is located between the first doped regions 21, the film layer of the patterned marking portion 41 is the same as the film layer of the second doped region 22.

[0090] When the pattern marking portion 41 is located between the second doped regions 22, the composition of the pattern marking portion 41 is the same as that of the film layer of the first doped region 21.

[0091] Although the W1 dimension of the isolation groove 42 is relatively large, the graphic mark portion 41 located at the center of the isolation groove 42 can have the same film composition as the first doped region 21 or the second doped region 22. This not only improves the recognition effect and positioning accuracy of the positioning mark structure 4, but also enables the graphic mark portion 41 to perform the same function as the first doped region 21 or the second doped region 22, thus supporting the improvement of the photoelectric conversion efficiency of the battery. This compact layout avoids excessive occupation of the limited space of the backlight surface of the silicon substrate 1. By matching the film layer of the graphic mark portion 41 with the film layer of the first doped region 21 or the second doped region 22, a reasonable arrangement of the position and size of each region is achieved, reducing space waste. This not only helps to increase the overall photoelectric conversion area of ​​the battery, thereby improving the photoelectric conversion efficiency of the battery, but also makes the layout of the graphic mark portion 41 and the doped region 2 more coordinated, further optimizing the structural design of the battery.

[0092] Secondly, embodiments of this application provide a photovoltaic module.

[0093] A photovoltaic module, comprising a solar cell 100 as mentioned in the first aspect.

[0094] The following describes the fabrication method of a solar cell 100, taking the first doping region 21 as a P-type doping region and the second doping region 22 as an N-type doping region as an example:

[0095] The silicon wafer undergoes a polishing process.

[0096] Fabrication of P-type doped region: A first silicon oxide layer, a boron-doped polysilicon layer, and a borosilicate glass layer are sequentially deposited on the back surface of a silicon wafer. The first silicon oxide layer, boron-doped polysilicon layer, and borosilicate glass layer can be fabricated by plasma chemical vapor deposition.

[0097] First laser processing and first chemical etching: The first silicon oxide layer, boron-doped polysilicon layer and borosilicate glass layer are removed from the P-type doped region and other areas outside the patterned marking part 41 by laser and chemical etching methods.

[0098] Fabrication of N-type doped regions: A second silicon oxide layer, a phosphorus-doped polysilicon layer, and a phosphorus-silicon glass layer are sequentially deposited on the back surface of the silicon wafer. Then, a second laser is used to remove the phosphorus-silicon glass layer outside the N-type doped regions. Next, a second chemical etching process is used to form P-type doped regions, N-type doped regions, isolation regions 3, patterned marking portions 41, and isolation grooves 42. In this step, the fabrication of isolation grooves 42 is completed simultaneously with the formation of P-type doped regions, N-type doped regions, and isolation regions 3. Since the film layer at the patterned marking portions 41 was previously retained, the patterned marking portions 41 are formed.

[0099] The process then involves texturing, removing the remaining borosilicate glass layer, applying a passivation layer, and fabricating electrodes to form the solar cell 100.

[0100] During the first laser processing, since the patterned marking portion 41 is not yet formed, positioning is generally achieved by identifying the edge of the silicon wafer. After the first laser processing, the film layer located in the region of the patterned marking portion 41 is retained and protrudes relative to the isolation groove region removed by the laser. Therefore, during the second laser processing, laser patterning can be performed by identifying and positioning the relatively protruding region of the patterned marking portion 41. After the second chemical etching process is completed, the patterned marking portion 41 is formed. Accurate identification and positioning are achieved in the subsequent laser and printing processes required for electrode fabrication, thereby enabling accurate control of the electrode position.

[0101] The solar cells and photovoltaic modules disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the solar cells and photovoltaic modules of this application and their core ideas. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solar cell, characterized in that, The solar cell includes: Silicon substrate; The patterned doped regions are located on the back surface of the silicon substrate. The doped regions include a first doped region and a second doped region distributed in an interdigitated pattern. One of the first doped region and the second doped region is a P-type doped region and the other is an N-type doped region. An isolation region is located on the back surface of the silicon substrate, and the isolation region is used to separate the first doped region and the second doped region; A positioning mark structure is located on the back surface of the silicon substrate, and the positioning mark structure is used as a positioning mark for pattern making; The positioning mark structure includes: A graphic marking portion, wherein the graphic marking portion is disposed in the doped region and separates the doped region; An isolation groove connected end to end, the isolation groove being arranged circumferentially around the graphic mark portion; In a first direction, the width of the isolation groove is D, the width of the isolation area is L1, D is greater than L1, and the first direction is the width direction of the isolation area.

2. The solar cell according to claim 1, characterized in that, The value of D is 1 μm to 200 μm larger than that of L1.

3. The solar cell according to claim 2, characterized in that, The D is 11μm to 400μm, and the L1 is 10μm to 200μm.

4. The solar cell according to claim 1, characterized in that, Along the thickness direction of the silicon substrate, the orthographic projection outline of the graphic mark includes either a square or a rectangle, and the orthographic projection outer outline of the isolation groove includes either a square or a rectangle.

5. The solar cell according to claim 4, characterized in that, The isolation groove and the positioning mark combine to form a U-shaped structure; Along the first direction, the side length of the orthographic projection outer contour of the isolation groove is W1, the side length of the orthographic projection contour of the graphic mark is N1, and the ratio of N1 to W1 is (200~1000)∶(222~1800). Along the second direction, the side length of the orthographic projection outer contour of the isolation groove is W2, the side length of the orthographic projection contour of the graphic mark is N2, the ratio of N2 to W2 is (200~1000)∶(222~1800), and the second direction is perpendicular to the first direction.

6. The solar cell according to claim 5, characterized in that, Along the first direction, the width of the first doped region is L2, and the width of the second doped region is L3; W1 is greater than at least one of L2 or L3.

7. The solar cell according to claim 6, characterized in that, W1 is 222μm to 1800μm, L2 is 200μm to 1000μm, and L3 is 200μm to 1000μm.

8. The solar cell according to claim 5, characterized in that, The graphic marker portion has at least one first side parallel to the second direction; When the graphic mark is located in the first doped region, the first edge is aligned with the first side edge in the first doped region that is parallel to the second direction; When the graphic mark is located in the second doped region, the first side is aligned with the second side of the second doped region that is parallel to the second direction.

9. The solar cell according to any one of claims 1 to 8, characterized in that, When the patterned marking portion is located between the first doped regions, the film layer of the patterned marking portion is the same as the film layer of the second doped region; When the patterned marking portion is located between the second doped regions, the composition of the patterned marking portion is the same as that of the film layer of the first doped region.

10. A photovoltaic module, characterized in that, Includes the solar cell as described in any one of claims 1-9.

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