Solar cell and preparation method thereof

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell and a preparation method thereof, the solar cell comprises a cell substrate, first grid lines and second grid lines, the plurality of second grid lines comprise first sub-grid line groups and second sub-grid line groups which are alternately arranged along a second direction, the first sub-grid line group comprises a plurality of first sub-grid lines extending in the second direction, the second sub-grid line group comprises a plurality of second sub-grid lines extending in the second direction, and the first sub-grid lines and the adjacent second sub-grid lines are arranged in a staggered mode in the first direction; each first sub-grid line comprises a first main body part and first connecting parts located at the two ends of the first main body part, each second sub-grid line comprises a second main body part and second connecting parts located at the two ends of the second main body part, the first connecting parts and the second connecting parts are alternately arranged in the first direction, and the first grid lines are electrically connected with the first connecting parts and the second connecting parts. The embodiment of the invention at least can reduce the grid breaking risk and improve the performance of the solar cell.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of photovoltaics, and in particular, to a solar cell and a method for manufacturing the same. Background Art

[0002] With the continuous development of new energy power generation technologies, the proportion of new energy power generation is increasing continuously. New energy can be obtained through a wide range of sources and has no polluting impact on the environment. Photovoltaic power generation can generate electric energy by obtaining the radiant energy of sunlight. Photovoltaic power generation is achieved through solar cells. Solar cells have the photovoltaic effect, that is, the photoelectric effect, and can generate current under the irradiation of sunlight, thereby generating electricity.

[0003] When manufacturing a solar cell, the screen printing process will be involved. In the screen printing process, grid lines are formed by screen printing electrode paste. The grid lines are an important part of the solar cell and play a role in collecting and transporting electrons. The screen is designed according to the structure of the grid lines, and the characteristics of the grid lines formed by the screen printing process affect the welding effect during the subsequent component welding process. However, in the related art, there is a risk of broken grids in the grid line structure of the solar cell during the subsequent welding process, which affects the welding effect of the subsequent components. Therefore, how to design the structure of the grid lines to reduce the risk of broken grids is a problem that needs to be solved. Summary of the Invention

[0004] Embodiments of the present disclosure provide a solar cell and a method for manufacturing the same, which can at least reduce the risk of broken grids and improve the performance of the solar cell.

[0005] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a solar cell, including: a cell substrate; a plurality of first grid lines located on the cell substrate, the first grid lines extending along a first direction, and the plurality of first grid lines being spaced apart along a second direction; a plurality of second grid lines located on the cell substrate, the plurality of second grid lines including a first sub-grid line group and a second sub-grid line group alternately arranged along the second direction, the first sub-grid line group including a plurality of first sub-grid lines extending along the second direction, the second sub-grid line group including a plurality of second sub-grid lines extending along the second direction, and the first sub-grid lines and the adjacent second sub-grid lines being arranged in a staggered manner along the first direction; the first sub-grid line includes a first main body portion and first connection portions located at both ends of the first main body portion, the second sub-grid line includes a second main body portion and second connection portions located at both ends of the second main body portion, the first connection portions and the second connection portions being alternately arranged along the first direction, the first grid line being located between the first main body portion and the second main body portion and being electrically connected to the first connection portions and the second connection portions; wherein, in a direction away from the first main body portion, the width of the first connection portion gradually increases along the second direction, and in a direction away from the second main body portion, the width of the second connection portion gradually increases along the second direction.

[0006] In some embodiments, along the second direction, the distance between the first grid line and the adjacent first main body portion is equal to the distance between the first grid line and the adjacent second main body portion.

[0007] In some embodiments, the first connection portion includes a first end adjacent to the first main body portion and a second end away from the first main body portion, the second connection portion includes a third end adjacent to the second main body portion and a fourth end away from the second main body portion; along the second direction, the distance between the first grid line and the adjacent first end is greater than or equal to the distance between the first grid line and the adjacent second end, and the distance between the first grid line and the adjacent third end is greater than or equal to the distance between the first grid line and the adjacent second end.

[0008] In some embodiments, along the second direction, the distance between the first grid line and the first end is 20 μm to 2000 μm, the distance between the first grid line and the second end is 0 to 1000 μm, the distance between the first grid line and the third end is 20 μm to 2000 μm, and the distance between the first grid line and the fourth end is 0 to 1000 μm.

[0009] In some embodiments, the first connecting portion includes a first end adjacent to the first main body portion and a second end away from the first main body portion, and the second connecting portion includes a third end adjacent to the second main body portion and a fourth end away from the second main body portion; the ratio of the width of the first end in the first direction to the width of the second end in the first direction is 0.025 to 1, and the ratio of the width of the third end in the first direction to the width of the fourth end in the first direction is 0.025 to 1.

[0010] In some embodiments, the width of the first end in the first direction is 5 μm to 80 μm, the width of the second end in the first direction is 10 μm to 200 μm, the width of the third end in the first direction is 5 μm to 80 μm, and the width of the fourth end in the first direction is 10 μm to 200 μm.

[0011] In some embodiments, the length of the first connecting portion in the second direction is 20 μm to 2000 μm, the length of the first main body portion in the second direction is 500 μm to 20000 μm, the length of the second connecting portion in the second direction is 20 μm to 2000 μm, and the length of the second main body portion in the second direction is 500 μm to 20000 μm.

[0012] In some embodiments, in the thickness direction of the battery substrate, the height of the top surface of the first connecting portion facing away from the battery substrate surface relative to the battery substrate surface is the first height, the height of the top surface of the second connecting portion facing away from the battery substrate surface relative to the battery substrate surface is the second height, and the height of the top surface of the first grid line facing away from the battery substrate surface relative to the battery substrate surface is the third height; the ratio of the first height to the third height is 1.5 to 12, and the ratio of the second height to the third height is 1.5 to 12.

[0013] In some embodiments, the first height is 6 μm to 12 μm, the second height is 6 μm to 12 μm, and the third height is 1 μm to 4 μm.

[0014] According to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure further provides a method for manufacturing a solar cell, including providing a cell substrate; printing a first grid line on the surface of the cell substrate by using a first stencil, the first stencil being provided with a plurality of first opening grooves penetrating through the first stencil, the first opening grooves extending in a first direction, and the plurality of first opening grooves being arranged at intervals in a second direction; printing a second grid line on the surface of the cell substrate by using a second stencil, the second stencil being provided with a second opening groove group and a third opening groove group alternately arranged in the second direction, the second opening groove group including a plurality of second opening grooves arranged at intervals in the first direction, the first opening grooves extending in the second direction, the third opening groove group including a plurality of third opening grooves arranged at intervals in the first direction, the third opening grooves extending in the second direction, the second opening grooves and the adjacent third opening grooves being arranged in a staggered manner in the first direction, the second opening grooves being used to form first sub-grid lines, and the second opening grooves being used to form second sub-grid lines.

[0015] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0016] In the solar cell provided by the embodiment of the present disclosure, the first grid line is the main grid line, and the second grid line is the fine grid line. The second grid line includes a first sub-grid line group and a second sub-grid line group alternately distributed in the second direction, and the adjacent first sub-grid lines and second sub-grid lines are arranged in a staggered manner in the first direction, that is, the adjacent first sub-grid lines and second sub-grid lines are not located on the same straight line. Therefore, when the adjacent first sub-grid lines and second sub-grid lines are arranged on the same straight line due to the opening, it is possible to avoid the situation that an additional overlapping body is required to overlap the adjacent first sub-grid lines and second sub-grid lines due to the limitation of the opening length of the full-opening stencil on the same straight line, thereby avoiding the occurrence of the broken grid phenomenon caused by the arrangement of the overlapping body, and further reducing the broken grid risk of the solar cell.

[0017] In the embodiment of the present disclosure, the first grid line is electrically connected to the second grid line through a first connection portion and a second connection portion. In the direction away from the first main portion, the width of the first connection portion gradually increases in the second direction. In the direction away from the second main portion, the width of the second connection portion gradually increases in the second direction. That is, the portion of the first connection portion close to the first grid line has a larger width, and the width of the second connection portion close to the first grid line is larger, so that the contact area between the first grid line and the first connection portion and between the first grid line and the second connection portion is larger, which is beneficial to improving the carrier collection rate of the first grid line on the second grid line, and thus can improve the performance of the solar cell.

[0018] In addition, the first grid line is electrically connected to the second grid line through the first connection part and the second connection part. The first connection part and the second connection part are part of the second grid line. That is, the first connection part and the second connection part are made of fine grid paste. When using a full - opening stencil to print the fine grid paste, the plasticizing height of the fine grid paste is relatively high, so that the plasticizing heights of the first connection part and the second connection part are relatively high, and it is not easy to occur welding fusing during the component welding process. Therefore, as part of the second fine grid, the first connection part and the second connection part can reduce the risk of welding breakage. Description of the Drawings

[0019] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments unless otherwise stated. The figures in the drawings do not constitute a proportional limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the prior art, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a partial structural schematic diagram of a solar cell in the related art;

[0021] Figure 2 It is a structural schematic diagram of a solar cell provided by an embodiment of the present disclosure;

[0022] Figure 3 It is a structural schematic diagram of a first sub - grid line group in a solar cell provided by an embodiment of the present disclosure;

[0023] Figure 4 It is a structural schematic diagram of a second sub - grid line group in a solar cell provided by an embodiment of the present disclosure;

[0024] Figure 5 It is a partial structural schematic diagram near the first grid line in a solar cell provided by an embodiment of the present disclosure;

[0025] Figure 6 It is a cross - sectional view of a battery substrate and the first grid line in a solar cell provided by an embodiment of the present disclosure;

[0026] Figure 7 It is a cross - sectional view of a battery substrate, the first connection part and the second connection part in a solar cell provided by an embodiment of the present disclosure. Detailed Embodiments

[0027] When manufacturing a solar cell, it will go through the screen printing process. The main grid and fine grid are formed on the surface of the cell substrate through the screen printing process. Screen printing is carried out using a screen plate. The screen plate is designed with openings through which the printing paste can pass. The paste is printed on the surface of the cell substrate to form the main grid and the fine grid.

[0028] Figure 1 It is a schematic diagram of a partial structure of a solar cell in the related art. Figure 1 It shows the connection and arrangement relationship of the main grid and the fine grid formed on the cell substrate using a full-opening screen plate in the related art.

[0029] The full-opening screen plate is a screen plate with a 100% opening rate. The main body is no longer woven from silk screen, but made of alloy steel sheet, and the printing openings are obtained by laser grooving. The opening rate of the working area of the screen plate printing reaches 100%, that is, all printing patterns have no silk screen or other similar structures blocking. Since there is no silk screen blocking in the grooved area of the full-opening screen plate, it can greatly improve the transmittance of the paste and save the consumption of the paste.

[0030] However, because the full-opening screen plate does not have a silk screen or other similar structures blocking, there is a risk of screen plate collapse when the length of the opening in the first direction X is too long. Therefore, the length of the opening of the full-opening screen plate in the first direction X is limited. As Figure 1 shown, when printing the fine grid using the full-opening screen plate, the entire fine grid extending along the first direction X will be divided into multiple sub-fine grids 102. Adjacent sub-fine grids 102 are provided with overlapping bodies 103 for electrical connection, and the fine grid is electrically connected to the main grid 101.

[0031] Among them, the overlapping body 103 usually uses the main grid paste and is printed together with the main grid 101. The plasticizing height of the main grid paste after printing using the full-opening screen plate is relatively low, making the overlapping body 103 prone to welding melting during the component welding process, resulting in the disconnection between the fine grid and the main grid 101. Therefore, the risk of broken grid in the solar cell in the related art is relatively high.

[0032] The embodiments of the present disclosure provide a solar cell and a manufacturing method thereof. In the solar cell provided by the embodiments of the present disclosure, adjacent first sub-grid lines and second sub-grid lines are misaligned in the first direction, that is, adjacent first sub-grid lines and second sub-grid lines are not on the same straight line. Therefore, it can be avoided that when the adjacent first sub-grid lines and second sub-grid lines are arranged on the same straight line due to the opening, being restricted by the opening length of the full-opening screen plate on the same straight line and the need to use an additional overlapping body to overlap the adjacent first sub-grid lines and second sub-grid lines, thereby avoiding the occurrence of broken grid phenomenon caused by setting the overlapping body, and further reducing the broken grid risk of the solar cell.

[0033] The width of the part of the first connection part close to the first grid line is relatively large, and the width of the second connection part close to the first grid line is relatively large, so that the contact area between the first grid line and the first connection part and between the first grid line and the second connection part is relatively large, which is beneficial to improving the carrier collection rate of the first grid line on the second grid line, and thus can improve the performance of the solar cell.

[0034] In addition, the first grid line is electrically connected to the second grid line through the first connection part and the second connection part. The first connection part and the second connection part are used as part of the second grid line. That is, the first connection part and the second connection part are prepared with fine grid paste, and when using a full-opening screen printing for the fine grid paste, the shaping height of the fine grid paste is relatively high, so that the shaping heights of the first connection part and the second connection part are relatively high, and it is not easy to occur welding fusing during the component welding process. Therefore, the first connection part and the second connection part as part of the second fine grid can reduce the risk of welding breakage.

[0035] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0036] Referring to "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may mean: there is A, there is both A and B, and there is B. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0038] In the description of the embodiments of the present disclosure, the term "a plurality" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0039] In the description of the embodiments of the present disclosure, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present disclosure.

[0040] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0041] In the corresponding drawings of the embodiments of the present disclosure, for better understanding and convenience of description, the thickness and area of the layer are enlarged. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0042] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise stated, other components are not excluded, and other components may further be included. In addition, when a component such as a layer, film, region, or plate is referred to as "on / at" another component, it can be "directly on" the other component (that is, on the surface of the other component and there is no other component between them), or there can be another component between them. In addition, when a layer, film, region, plate, etc. is "directly located on" another component, or when a layer, film, region, plate, etc. is located on the surface of another component, it means that there is no other component between them.

[0043] The following will elaborate on the embodiments of the present disclosure in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented to help readers better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can still be implemented.

[0044] Figure 2 It is a schematic structural diagram of a solar cell provided by an embodiment of the present disclosure; Figure 3 It is a schematic structural diagram of a first sub-grid line group in a solar cell provided by an embodiment of the present disclosure; Figure 4 It is a schematic structural diagram of a second sub-grid line group in a solar cell provided by an embodiment of the present disclosure; Figure 5 It is a schematic partial structural diagram near a first grid line in a solar cell provided by an embodiment of the present disclosure.

[0045] With reference to Figures 2 to 5 , the solar cell includes: a cell substrate 200; a plurality of first grid lines 201, the first grid lines 201 are located on the cell substrate 200, the first grid lines 201 extend along a first direction X, and the plurality of first grid lines 201 are arranged at intervals along a second direction Y; a plurality of second grid lines 202, the second grid lines 202 are located on the cell substrate 200, the plurality of second grid lines 202 include a first sub-grid line group 212 and a second sub-grid line group 222 that are alternately arranged along the second direction Y, the first sub-grid line group 212 includes a plurality of first sub-grid lines 232 that extend along the second direction Y, the second sub-grid line group 222 includes a plurality of second sub-grid lines 242 that extend along the second direction Y, and the first sub-grid lines 232 and the adjacent second sub-grid lines 242 are arranged in a staggered manner along the first direction X; the first sub-grid line 232 includes a first main body portion 2321 and first connection portions 2322 located at both ends of the first main body portion 2321, the second sub-grid line 242 includes a second main body portion 2421 and second connection portions 2422 located at both ends of the second main body portion 2421, the first connection portions 2322 and the second connection portions 2422 are alternately arranged along the first direction X, the first grid line 201 is located between the first main body portion 2321 and the second main body portion 2421 and is electrically connected to the first connection portions 2322 and the second connection portions 2422; wherein, in the direction away from the first main body portion 2321, the width of the first connection portion 2322 gradually increases along the second direction Y, and in the direction away from the second main body portion 2421, the width of the second connection portion 2422 gradually increases along the second direction Y.

[0046] The solar cell is used to absorb sunlight and convert light energy into electrical energy.

[0047] In some embodiments, the battery substrate 200 may be a PERC cell (Passivated Emitter Rear Cell), an IBC cell (Interdigitated Back Contact), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), a thin-film solar cell, or a tandem cell, or any combination thereof. Among them, the thin-film solar cell includes, but is not limited to, a perovskite thin-film solar cell, a copper indium selenide thin-film solar cell, a gallium arsenide thin-film solar cell, and a cadmium sulfide thin-film solar cell. The tandem cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin-film cell.

[0048] In some embodiments, the battery substrate 200 may be a monocrystalline silicon photovoltaic cell, a polycrystalline silicon photovoltaic cell, an amorphous silicon photovoltaic cell, or a multi-component compound photovoltaic cell. Specifically, the multi-component compound photovoltaic cell may be a cadmium sulfide photovoltaic cell, a gallium arsenide photovoltaic cell, a copper indium selenide photovoltaic cell, or a perovskite photovoltaic cell.

[0049] The battery substrate 200 includes a substrate, a doped conductive layer, and a passivation layer. The substrate has opposite first and second surfaces, and the doped conductive layer and the passivation layer are disposed on the first surface and / or the second surface. The doped conductive layer is located between the substrate and the passivation layer.

[0050] The first grid line 201 and the second grid line 202 are located on the first surface and / or the second surface.

[0051] The second grid line 202 is in electrical contact with the doped conductive layer to lead out the carriers formed by the battery substrate 200. The first grid line 201 is used to collect the carriers led out by the first grid line 201. Specifically, the first grid line 201 is the main grid, and the second grid line 202 is the fine grid.

[0052] It can be understood that the material of the first grid line 201 is different from that of the second grid line 202. In other words, the paste for forming the first grid line 201 is different from the paste for forming the second grid line 202. The first grid line 201 is composed of a non-burn-through paste and is located on the surface of the passivation layer without being in electrical contact with the doped conductive layer. The second grid line 202 is formed by a burn-through paste, and the second grid line 202 penetrates through the passivation layer and is electrically connected to the doped conductive layer.

[0053] Among them, the traditional paste includes a mixture of metal powder, glass powder, and organic carrier. The non-burn-through paste refers to a paste with a glass powder content lower than that of the traditional paste. During the sintering process, it has weak burn-through ability and does not require or cannot burn through the passivation layer. The burn-through paste refers to a paste with strong burn-through ability that can burn through the passivation layer during the sintering process.

[0054] In addition, since the paste for forming the first gate line 201 is different from the paste for forming the second gate line 202, the plasticizing heights of the first gate line 201 and the second gate line 202 are different after printing. Specifically, the plasticizing height of the first gate line 201 is lower, and the plasticizing height of the second gate line 202 is higher.

[0055] The second gate line 202 includes a first sub-gate line group 212 and a second sub-gate line group 222 that are alternately distributed along the second direction Y, and adjacent first sub-gate lines 232 and second sub-gate lines 242 are staggeredly distributed along the first direction X, so that adjacent first sub-gate lines 232 and second sub-gate lines 242 may not be located on the same straight line. Therefore, when the adjacent first sub-gate line and the second sub-gate line are set on the same straight line due to the opening, it is necessary to use an additional overlapping body to overlap the adjacent first sub-gate line and the second sub-gate line due to the limitation of the opening length of the full-opening stencil on the same straight line. Thus, the occurrence of the broken gate phenomenon caused by setting the overlapping body can be avoided, and further, the broken gate risk of the solar cell can be reduced.

[0056] The first connecting portion 2322 in the first sub-gate line 232 and the second connecting portion 2422 of the second sub-gate line 242 are used for electrically connecting with the first gate line 201.

[0057] In some embodiments, along the second direction Y, the distance between the first gate line 201 and the adjacent first main body portion 2321 is equal to the distance between the first gate line 201 and the adjacent second main body portion 2421. That is, the first gate line 201 is located exactly in the middle of the adjacent first main body portion 2321 and the adjacent second main body portion 2421 to ensure that the rate at which the first gate line 201 collects carriers on the first main body portion 2321 is basically the same as the rate at which the second gate line 202 collects carriers on the second main body portion 2421.

[0058] In the direction away from the first main body portion 2321, the width of the first connection portion 2322 gradually increases along the second direction Y. In the direction away from the second main body portion 2421, the width of the second connection portion 2422 gradually increases along the second direction Y. That is, the width of the portion of the first connection portion 2322 close to the first gate line 201 is larger, and the width of the second connection portion 2422 close to the first gate line 201 is larger. As a result, the contact areas between the first gate line 201 and the first connection portion 2322 and between the first gate line 201 and the second connection portion 2422 are larger, which is beneficial to improving the rate at which the first gate line 201 collects carriers on the second gate line 202, thereby improving the performance of the solar cell.

[0059] Continuing to refer to Figures 2 to 5 In some embodiments, the first connection portion 2322 includes a first end 21 adjacent to the first main body portion 2321 and a second end 22 away from the first main body portion 2321. The second connection portion 2422 includes a third end 23 adjacent to the second main body portion 2421 and a fourth end 24 away from the second main body portion 2421. The first end 21 and the second end 22 are oppositely arranged, and the width of the second end 22 is greater than the width of the first end 21. The third end 23 and the fourth end 24 are oppositely arranged, and the width of the fourth end 24 is greater than the width of the third end 23.

[0060] In some embodiments, the ratio of the width of the first end 21 along the first direction X to the width of the second end 22 along the first direction X is 0.025 - 1, such as 0.025, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, etc. When the ratio of the width of the first end 21 to the width of the second end 22 is within the above range, it can ensure that the width of the second end 22 close to the first gate line 201 is larger, so that the first gate line 201 and the first sub - gate line 232 have a larger contact area, thereby improving the rate at which the first gate line 201 collects carriers on the first sub - gate line 232.

[0061] The ratio of the width of the third end 23 along the first direction X to the width of the fourth end 24 along the first direction X is 0.025 - 1, such as 0.025, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, etc. When the ratio of the width of the third end 23 to the width of the fourth end 24 is within the above range, it can ensure that the width of the fourth end 24 close to the first gate line 201 is larger, so that the first gate line 201 and the second sub - gate line 242 have a larger contact area, thereby improving the rate at which the first gate line 201 collects carriers on the second sub - gate line 242.

[0062] In some embodiments, the width of the first end 21 in the first direction X is 5 μm to 80 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm or 80 μm, etc., and the width of the second end 22 in the first direction X is 10 μm to 200 μm, such as 10 μm, 20 μm, 40 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm or 200 μm, etc. When the widths of the first end 21 and the second end 22 are within the above ranges, it can be ensured that the width of the second end 22 close to the first grid line 201 is larger, so that the first grid line 201 and the first sub-grid line 232 have a larger contact area, thereby improving the rate at which the first grid line 201 collects carriers on the first sub-grid line 232. It can also avoid the situation where the area of the solar cell that absorbs light is blocked by the first connecting portion 2322 due to the excessive widths of the first end 21 and the second end 22.

[0063] In some embodiments, the width of the third end 23 in the first direction X is 5 μm to 80 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm or 80 μm, etc., and the width of the fourth end 24 in the first direction X is 10 μm to 200 μm, such as 10 μm, 20 μm, 40 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm or 200 μm, etc. When the widths of the third end 23 and the fourth end 24 are within the above ranges, it can be ensured that the width of the fourth end 24 close to the first grid line 201 is larger, so that the first grid line 201 and the second sub-grid line 242 have a larger contact area, thereby improving the rate at which the first grid line 201 collects carriers on the second sub-grid line 242. It can also avoid the situation where the area of the solar cell that absorbs light is blocked by the second connecting portion 2422 due to the excessive widths of the third end 23 and the fourth end 24.

[0064] In some embodiments, along the second direction Y, the distance L1 between the first grid line 201 and the adjacent first end 21 is greater than or equal to the distance L2 between the first grid line 201 and the adjacent second end 22, and the distance L3 between the first grid line 201 and the adjacent third end 23 is greater than or equal to the distance L4 between the first grid line 201 and the adjacent second end 22. Moreover, along the direction away from the first main body portion 2321, the width of the first connecting portion 2322 gradually increases in the second direction Y, and along the direction away from the second main body portion 2421, the width of the second connecting portion 2422 gradually increases in the second direction Y. In this way, the contact areas between the first grid line 201 and the first connecting portion 2322 and the second connecting portion 2422 are relatively large, which is beneficial to improving the rate at which the first grid line 201 collects carriers on the second grid line 202, thereby improving the performance of the solar cell.

[0065] In some embodiments, along the second direction Y, the distance L1 between the first gate line 201 and the adjacent first end 21 is 20 μm to 2000 μm, such as 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm, 1000 μm, 1200 μm, 1400 μm, 1800 μm or 2000 μm, etc. The distance L2 between the first gate line 201 and the adjacent second end 22 is 0 to 1000 μm, such as 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm or 1000 μm, etc. When the distances between the first gate line 201 and the adjacent first end 21 and the adjacent second end 22 are within the above ranges, a relatively large contact area between the first gate line 201 and the first sub-gate line 232 can be ensured, which is beneficial to improving the carrier collection rate of the first gate line 201 on the first sub-gate line 232, thereby improving the performance of the solar cell.

[0066] Along the second direction Y, the distance L3 between the first gate line 201 and the adjacent third end 23 is 20 μm to 2000 μm, such as 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm, 1000 μm, 1200 μm, 1400 μm, 1800 μm or 2000 μm, etc. The distance L4 between the first gate line 201 and the adjacent fourth end 24 is 0 to 1000 μm, such as 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm or 1000 μm, etc. When the distances between the first gate line 201 and the adjacent third end 23 and the adjacent fourth end 24 are within the above ranges, a relatively large contact area between the first gate line 201 and the second sub-gate line 242 can be ensured, which is beneficial to improving the carrier collection rate of the first gate line 201 on the second sub-gate line 242, thereby improving the performance of the solar cell.

[0067] In some embodiments, along the second direction Y, the length of the first connecting portion 2322 can be less than the length of the first main body portion 2321. Also, the width of the first connecting portion 2322 along the first direction X is greater than or equal to the width of the first main body portion 2321 along the first direction X, that is, when the lengths of the first connecting portion 2322 and the first main body portion 2321 are the same, the light-shielding area of the first connecting portion 2322 is larger. Setting the length of the first connecting portion 2322 to be less than the length of the first main body portion 2321 makes the light-shielding area of the first sub-gate line 232 on the battery substrate 200 smaller, thereby improving the performance of the solar cell.

[0068] In some embodiments, the length of the first connecting portion 2322 in the second direction Y is 20 μm to 2000 μm, such as 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm, 1000 μm, 1200 μm, 1400 μm, 1800 μm or 2000 μm, etc.; the length of the first main body portion 2321 in the second direction Y is 500 μm to 20000 μm, such as 500 μm, 1000 μm, 3000 μm, 6000 μm, 9000 μm, 12000 μm, 14000 μm, 16000 μm, 18000 μm or 20000 μm, etc. When the lengths of the first connecting portion 2322 and the first main body portion 2321 are within the above ranges, it is possible to avoid the problem of excessive light shielding area of the first sub-grid line 232 on the battery substrate 200 caused by the too long length of the first connecting portion 2322, and it is also possible to avoid the situation where the carrier collection efficiency of each first sub-grid line 232 is low due to the too short lengths of the first connecting portion 2322 and the first main body portion 2321.

[0069] In some embodiments, along the second direction Y, the length of the second connecting portion 2422 can be less than the length of the second main body portion 2421. Also, the width of the second connecting portion 2422 in the first direction X is greater than or equal to the width of the second main body portion 2421 in the first direction X, that is, when the lengths of the second connecting portion 2422 and the second main body portion 2421 are the same, the light shielding area of the second connecting portion 2422 is larger. By setting the length of the second connecting portion 2422 to be less than the length of the second main body portion 2421, the light shielding area of the second sub-grid line 242 on the battery substrate 200 can be made smaller, thereby improving the performance of the solar cell.

[0070] In some examples, the length of the second connecting portion 2422 in the second direction Y is 20 μm to 2000 μm, such as 20 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm, 1000 μm, 1200 μm, 1400 μm, 1800 μm or 2000 μm, etc.; the length of the second main body portion 2421 in the second direction Y is 500 μm to 20000 μm, such as 500 μm, 1000 μm, 3000 μm, 6000 μm, 9000 μm, 12000 μm, 14000 μm, 16000 μm, 18000 μm or 20000 μm, etc. When the lengths of the second connecting portion 2422 and the second main body portion 2421 are within the above ranges, it is possible to avoid the problem of excessive light shielding area of the second sub-grid line 242 on the battery substrate 200 caused by the too long length of the second connecting portion 2422, and it is also possible to avoid the situation where the carrier collection efficiency of each second sub-grid line 242 is low due to the too short lengths of the second connecting portion 2422 and the second main body portion 2421.

[0071] Figure 6 A cross-sectional view of a cell substrate and a first grid line in a solar cell provided by an embodiment of the present disclosure, Figure 7 A cross-sectional view of a cell substrate, a first connecting portion, and a second connecting portion in a solar cell provided in an embodiment of the present disclosure.

[0072] Combination Figures 5 to 7 In some embodiments, along the thickness direction of the battery substrate 200, the height of the top surface of the first connecting portion 2322 away from the surface of the battery substrate 200 relative to the surface of the battery substrate 200 is a first height H1, the height of the top surface of the second connecting portion 2422 away from the surface of the battery substrate 200 relative to the surface of the battery substrate 200 is a second height H2, and the height of the top surface of the first gate line 201 away from the surface of the battery substrate 200 relative to the surface of the battery substrate 200 is a third height H3; the ratio of the first height H1 to the third height H3 is 1.5 to 12, for example, 1.5, 2, 3, 4, 6, 8, 10 or 12, etc.; the ratio of the second height H2 to the third height H3 is 1.5 to 12, for example, 1.5, 2, 3, 4, 6, 8, 10 or 12, etc.

[0073] Since the slurries used to form the first gate line 201 and the second gate line 202 are different, the third height H3 of the first gate line 201 is smaller, and the first height H1 of the first connection portion 2322 of the second gate line 202 and the second height H2 of the second connection portion 2422 of the second gate line 202 are larger.

[0074] It should be noted that in the embodiments of the present disclosure, the molding height of the main grid slurry mentioned can be Figure 7 The third height H3 shown, the molding height of the fine grid slurry can be Figure 6 The first height H1 or the second height H2 is shown.

[0075] In some embodiments, the first height H1 is 6 μm to 12 μm, such as 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm or 12 μm, etc.; the second height H2 is 6 μm to 12 μm, such as 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm or 12 μm, etc. When the first height H1 and the second height H2 are within the above range, it can be avoided that the first height H1 and the second height H2 are too high, which affects the absorption of sunlight by the cell substrate 200, and it can also be avoided that the first height H1 and the second height H2 are too low, and the welding fuse occurs in the subsequent component welding process, thereby reducing the risk of grid breakage of the solar cell.

[0076] In some embodiments, the third height H3 is 1 μm to 4 μm, such as 1 μm, 2 μm, 3 μm, or 4 μm, etc. When the third height H3 is within the above range, it is possible to avoid the influence on the absorption of sunlight by the battery substrate 200 due to the excessive third height H3, and it is also possible to avoid the situation of welding fusing during the subsequent component welding process due to the too low third height H3, thereby reducing the risk of broken grids in the solar cell.

[0077] In some embodiments, along the first direction X, the distance between the first sub-grid line 232 and the adjacent second sub-grid line 242 is 30 μm to 3000 μm, such as 30 μm, 40 μm, 80 μm, 100 μm, 200 μm, 400 μm, 800 μm, 1000 μm, 1200 μm, 1400 μm, 1800 μm, 2000 μm, 2500 μm, or 3000 μm, etc. When the distance between the first sub-grid line 232 and the second sub-grid line 242 is within the above range, it is possible to avoid the situation that the carrier transport distance is relatively long due to the too large distance between the first sub-grid line 232 and the second sub-grid line 242, resulting in the reduction of the carrier collection efficiency of the first sub-grid line 232 and the second sub-grid line 242; it is also possible to avoid the situation that the number of the first sub-grid line 232 and the second sub-grid line 242 is too large due to the too small distance between the first sub-grid line 232 and the second sub-grid line 242, and the light-shielding area of the battery substrate 200 is relatively large, resulting in the reduction of the optical absorption performance of the solar cell.

[0078] In some embodiments, the width of the first grid line 201 along the second direction Y is 5 μm to 100 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, etc. When the width of the first grid line 201 is within the above range, it is possible to efficiently collect the carriers of the first grid line 201, and at the same time, it is also possible to avoid the situation that the sunlight absorption of the battery substrate 200 is blocked due to the too wide width.

[0079] In the above-mentioned solar cell, the adjacent first sub-grid line 232 and the second sub-grid line 242 are staggeredly distributed along the first direction X, which can avoid the situation that when the adjacent first sub-grid line 232 and the second sub-grid line 242 are arranged on the same straight line, it is necessary to use an additional overlapping body to overlap the adjacent first sub-grid line 232 and the second sub-grid line 242 due to the limitation of the opening length of the full-opening stencil on the same straight line, thereby avoiding the occurrence of the broken grid phenomenon caused by the setting of the overlapping body, and further reducing the risk of broken grids in the solar cell.

[0080] The width of the part of the first connection part 2322 close to the first gate line 201 is relatively large, and the width of the second connection part 2422 close to the first gate line 201 is relatively large. As a result, the contact area between the first gate line 201 and the first connection part 2322 and between the first gate line 201 and the second connection part 2422 is relatively large, which is beneficial to improving the carrier collection rate of the first gate line 201 on the second gate line 202, thereby improving the performance of the solar cell. In addition, the first connection part 2322 and the second connection part 2422 are made of fine grid paste. When using a full-opening screen printing for the fine grid paste, the shaping height of the fine grid paste is relatively high, so that the shaping heights of the first connection part 2322 and the second connection part 2422 are relatively high, and it is not easy to occur welding fusing during the component welding process. Therefore, the first connection part 2322 and the second connection part 2422, as part of the second fine grid, can reduce the risk of welding breakage.

[0081] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a preparation method for preparing the solar cell described in any one of the above embodiments. It should be noted that for the same or corresponding parts as those in the foregoing embodiments, reference may be made to the corresponding descriptions in the foregoing embodiments, and details will not be repeated hereinafter.

[0082] Reference Figures 2 to 4 , the preparation method of the solar cell includes: providing a cell substrate 200; printing a first gate line 201 on the surface of the cell substrate 200 by using a first screen. The first screen is provided with a plurality of first opening slots penetrating the first screen. The first opening slots extend along the first direction X, and the plurality of first opening slots are arranged at intervals along the second direction Y; printing a second gate line 202 on the surface of the cell substrate 200 by using a second screen. The second screen is provided with a second opening slot group and a third opening slot group arranged alternately along the second direction Y. The second opening slot group includes a plurality of second opening slots arranged at intervals along the first direction X. The first opening slots extend along the second direction Y. The third opening slot group includes a plurality of third opening slots arranged at intervals along the first direction X. The third opening slots extend along the second direction Y. The second opening slots and the adjacent third opening slots are arranged in a dislocation manner along the first direction X. The second opening slots are used to form first sub-gate lines 232, and the second opening slots are used to form second sub-gate lines 242.

[0083] The first screen can be a full-opening screen. Specifically, the first screen can be a full-opening steel plate.

[0084] The first screen can print the first gate line 201 on the first surface and / or the second surface of the cell substrate 200. The first opening slots of the first screen are used to form the first gate line 201.

[0085] The second screen can be a full-opening screen. Specifically, the second screen can be a full-opening steel plate.

[0086] The second stencil can print the second grid lines 202 on the first surface and / or the second surface of the battery substrate 200. The second opening groove of the second stencil is used to form the first sub-grid lines 232, and the third opening of the second stencil is used to form the second sub-grid lines 242.

[0087] In some embodiments, the first grid lines 201 can be printed by the first stencil first, and then the second grid lines 202 can be printed by the second stencil. Among them, the main grid paste is used for printing to form the first grid lines 201, and the shaping height of the first grid lines 201 formed by the first stencil is relatively low, while the fine grid paste is used for printing to form the second grid lines 202, and the shaping height of the second grid lines 202 formed by the second stencil is relatively high. Therefore, the first grid lines 201 with a relatively low shaping height are printed first, and then the second grid lines 202 with a relatively high shaping height are printed, so that at the junction of the second grid lines 202 and the first grid lines 201, the second grid lines 202 with a relatively high shaping height are located on the surface of the first grid lines 201 away from the battery substrate 200, which is beneficial to reducing the probability of welding fusing at the junction of the first grid lines 201 and the second grid lines 202 during the component welding process.

[0088] In other embodiments, the second grid lines 202 can also be printed by the second stencil first, and then the first grid lines 201 can be printed by the first stencil.

[0089] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure. In actual applications, various changes can be made in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A solar cell, characterized in that: include: Battery substrate; A plurality of first gate lines, wherein the first gate lines are located on the battery substrate, the first gate lines extend along a first direction, and the plurality of first gate lines are arranged at intervals along a second direction; A plurality of second grid lines, the second grid lines are located on the battery substrate, the plurality of second grid lines include a first sub-grid line group and a second sub-grid line group alternately arranged along the second direction, the first sub-grid line group includes a plurality of first sub-grid lines extending along the second direction, the second sub-grid line group includes a plurality of second sub-grid lines extending along the second direction, and the first sub-grid lines and adjacent second sub-grid lines are staggeredly arranged along the first direction; The first sub-gate line includes a first main body and first connecting parts located at two ends of the first main body, the second sub-gate line includes a second main body and second connecting parts located at two ends of the second main body, the first connecting parts and the second connecting parts are alternately arranged along the first direction, the first gate line is located between the first main body and the second main body, and is electrically connected to the first connecting parts and the second connecting parts; Wherein, the width of the first connection portion along the second direction gradually increases as it moves away from the first main body portion, and the width of the second connection portion along the second direction gradually increases as it moves away from the second main body portion.

2. The solar cell according to claim 1, characterized in that: Along the second direction, the distance between the first gate line and the adjacent first main body portion is equal to the distance between the first gate line and the adjacent second main body portion.

3. The solar cell according to claim 1, characterized in that The first connecting portion includes a first end adjacent to the first main body portion and a second end away from the first main body portion, and the second connecting portion includes a third end adjacent to the second main body portion and a fourth end away from the second main body portion; Along the second direction, the distance between the first gate line and the adjacent first end is greater than or equal to the distance between the first gate line and the adjacent second end, and the distance between the first gate line and the adjacent third end is greater than or equal to the distance between the first gate line and the adjacent second end.

4. The solar cell according to claim 3, characterized in that: Along the second direction, the distance between the first gate line and the first end is 20μm-2000μm, the distance between the first gate line and the second end is 0-1000μm, the distance between the first gate line and the third end is 20μm-2000μm, and the distance between the first gate line and the fourth end is 0-1000μm.

5. The solar cell according to claim 1, characterized in that: The first connecting portion includes a first end adjacent to the first main body portion and a second end away from the first main body portion, and the second connecting portion includes a third end adjacent to the second main body portion and a fourth end away from the second main body portion; The ratio of the width of the first end along the first direction to the width of the second end along the first direction is 0.025-1, and the ratio of the width of the third end along the first direction to the width of the fourth end along the first direction is 0.025-1.

6. The solar cell according to claim 5, characterized in that: The width of the first end along the first direction is 5 μm to 80 μm, the width of the second end along the first direction is 10 μm to 200 μm, the width of the third end along the first direction is 5 μm to 80 μm, and the width of the fourth end along the first direction is 10 μm to 200 μm.

7. The solar cell according to claim 1, characterized in that The length of the first connecting portion along the second direction is 20 μm to 2000 μm, the length of the first main body along the second direction is 500 μm to 20000 μm, the length of the second connecting portion along the second direction is 20 μm to 2000 μm, and the length of the second main body along the second direction is 500 μm to 20000 μm.

8. The solar cell according to claim 1, characterized in that Along the thickness direction of the battery substrate, the height of the top surface of the first connecting portion away from the battery substrate surface relative to the battery substrate surface is a first height, the height of the top surface of the second connecting portion away from the battery substrate surface relative to the battery substrate surface is a second height, and the height of the top surface of the first gate line away from the battery substrate surface relative to the battery substrate surface is a third height; the ratio of the first height to the third height is 1.5 to 12, and the ratio of the second height to the third height is 1.5 to 12.

9. The solar cell according to claim 8, characterized in that The first height is 6 μm to 12 μm, the second height is 6 μm to 12 μm, and the third height is 1 μm to 4 μm.

10. A method for preparing a solar cell, characterized in that: include: Providing a battery substrate; Printing first grid lines on the surface of the battery substrate using a first screen, wherein the first screen is provided with a plurality of first opening grooves penetrating the first screen, the first opening grooves extending along a first direction, and the plurality of first opening grooves being arranged at intervals along a second direction; A second screen is used to print the second grid line on the surface of the battery substrate, the second screen is provided with a second opening slot group and a third opening slot group alternately arranged along the second direction, the second opening slot group includes a plurality of second opening slots arranged at intervals along the first direction, the first opening slots extend along the second direction, the third opening slot group includes a plurality of third opening slots arranged at intervals along the first direction, the third opening slots extend along the second direction, the second opening slots and adjacent third opening slots are staggered along the first direction, the second opening slots are used to form a first sub-grid line, and the second opening slots are used to form a second sub-grid line.

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