Main-grid-free solar cell, solar cell string and photovoltaic module

Abstract

The utility model relates to the technical field of solar cells, in particular to a main-grid-free solar cell, a solar cell string and a photovoltaic module. The main-grid-free solar cell comprises a silicon substrate and a plurality of fine grids. The plurality of fine grids are arranged on the surface of the silicon substrate and are arranged into a plurality of columns, the plurality of columns of fine grids are arranged side by side, the side-by-side direction is a first direction, the arrangement direction of the fine grids in each column of fine grids is a second direction, the first direction and the second direction intersect, the odd-numbered columns of fine grids are a plurality of first fine grids arranged at intervals, and the odd-numbered columns of fine grids are second fine grids arranged at intervals. The even-numbered columns of fine grids are a plurality of second fine grids which are arranged at intervals, and every two adjacent columns of fine grids form a group of fine grid units. In any group of fine grid units, the first fine grids and the second fine grids are alternately arranged in the second direction, and the fine grid units are configured to be alternately and electrically connected with the first fine grids and the second fine grids according to the arrangement sequence in the second direction so as to be sequentially connected with the first fine grids and the second fine grids one by one, so that the current transmission path is optimized, and the transmission resistance is reduced.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a gridless solar cell, a solar cell string, and a photovoltaic module. Background Technology

[0002] In gridless solar cells, after current is collected through fine grids, it is no longer collected through the main grid. Instead, it is collected and transmitted by electrical connectors, such as solder ribbons. These connectors often connect the same row of fine grids in series. If the number of solder ribbons is equal to the number of rows of fine grids, the total length of the solder ribbons tends to be long, leading to a higher transmission resistance. Utility Model Content

[0003] This application discloses a gridless solar cell, a solar cell string, and a photovoltaic module, which can optimize the current transmission path and reduce transmission resistance.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a gridless solar cell, comprising:

[0005] Silicon substrate; and

[0006] Multiple fine gates are disposed on the surface of the silicon substrate and arranged in multiple columns. The multiple columns of fine gates are arranged side by side in a first direction. The arrangement direction of the fine gates in each column is a second direction. The first direction and the second direction intersect. The odd-numbered columns of fine gates are multiple first fine gates arranged at intervals, and the even-numbered columns of fine gates are multiple second fine gates arranged at intervals. Every two columns of adjacent fine gates form a group of fine gate units. In any group of fine gate units, the first fine gates and the second fine gates are alternately arranged in the second direction. The fine gate units are configured to alternately electrically connect the first fine gates and the second fine gates according to their arrangement order in the second direction, so as to connect the first fine gates and the second fine gates sequentially.

[0007] In a possible implementation of the first aspect, the series lengths of the two columns of fine gates in the fine gate unit are L1 and L2, respectively;

[0008] The fine gate unit is configured such that the shortest path connecting the first fine gate and the second fine gate sequentially is L3; where L3 < L1 + L2.

[0009] In one possible implementation of the first aspect, the fine grid is dot-shaped or line-segment-shaped.

[0010] In one possible implementation of the first aspect, the fine gate is dot-shaped, and the diameter of the fine gate is 5μm to 25μm.

[0011] In a possible implementation of the first aspect, the fine gate is linear, and in the first direction, the size of the fine gate is 0.01 mm to 10 mm; in the second direction, the size of the fine gate is 10 μm to 50 μm.

[0012] In a possible implementation of the first aspect, a plurality of the fine gates are arranged in multiple rows, the multiple rows of fine gates are spaced apart in a second direction, and each row of fine gates includes a plurality of fine gates spaced apart along the first direction; in two adjacent rows of fine gates, one row of fine gates is the first fine gate and the other row of fine gates is the second fine gate.

[0013] In a possible implementation of the first aspect, the spacing between two adjacent fine gates in the same row is 0.6 mm to 3 mm;

[0014] And / or, the spacing between two adjacent rows of the fine grid is 0.5 mm to 2 mm;

[0015] And / or, the first direction and the second direction are perpendicular.

[0016] Secondly, embodiments of this application disclose a solar cell string, comprising:

[0017] Several gridless solar cells as described in the first aspect; and

[0018] A plurality of electrical connectors, each of the electrical connectors being alternately connected to the first fine gate and the second fine gate in a fine gate unit according to the arrangement order in the second direction, so as to connect the first fine gate and the second fine gate sequentially.

[0019] In a possible implementation of the second aspect, the electrical connector is zigzag-shaped and includes a plurality of sub-connectors connected end to end in sequence. Each of the two connected fine grids is connected by one of the sub-connectors, and the two connected sub-connectors are arranged crosswise with the cross portion located on the fine grid.

[0020] And / or, the series lengths of two adjacent columns of the fine grids are L1 and L2, respectively, and the shortest length of the electrical connector is L3; wherein, L3 < L1 + L2;

[0021] And / or, the gridless solar cell is a passivated contact solar cell, a heterojunction solar cell, or a back contact solar cell;

[0022] And / or, the fine grid is in the shape of a dot, and the center of the fine grid is connected to the electrical connector;

[0023] And / or, the fine grid is straight, the length direction of the fine grid is in the same direction as the first direction, and in the first direction, one end of the fine grid near the center of the fine grid unit is connected to the electrical connector;

[0024] And / or, the electrical connector is a solder strip.

[0025] Thirdly, embodiments of this application disclose a photovoltaic module, including a solar cell string as described in the second aspect.

[0026] Compared with the prior art, the beneficial effects of this application are as follows: In this gridless solar cell, every two adjacent rows of fine grids form a group of fine grid units. In any group of fine grid units, the first and second fine grids are alternately arranged in the second direction. The fine grid units employ this alternating arrangement of the first and second fine grids, allowing the fine grid units to alternately connect the first and second fine grids according to their arrangement order in the second direction, thus connecting the first and second fine grids sequentially. In other words, multiple first and second fine grids in a single fine grid unit can be connected in series through a single electrical connector; that is, two rows of fine grids only require one electrical connector for series connection, thereby optimizing the current transmission path and reducing transmission resistance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a gridless solar cell disclosed in an embodiment of this application;

[0029] Figure 2 for Figure 1 A magnified view of a portion of region A shown in the image;

[0030] Figure 3 for Figure 1 A schematic diagram of the connection of the fine grid unit in the diagram;

[0031] Figure 4 for Figure 3 A magnified view of a portion of region B shown in the diagram;

[0032] Figure 5 for Figure 3 Another enlarged view of region B shown in the image;

[0033] Figure 6This is a schematic diagram of the structure of a gridless solar cell (with fine grids in the shape of dots) disclosed in an embodiment of this application;

[0034] Figure 7 This is a schematic diagram of a gridless solar cell (with a straight grid) disclosed in an embodiment of this application.

[0035] Figure 8 This is a schematic diagram of the structure of a solar cell string disclosed in an embodiment of this application;

[0036] Figure 9 for Figure 8 A magnified view of a portion of region C shown in the diagram;

[0037] Figure 10 for Figure 8 Another enlarged view of region C shown in the diagram;

[0038] Figure 11 for Figure 8 Another enlarged view of region C shown in the diagram;

[0039] Figure 12 This is another structural schematic diagram of a solar cell string disclosed in an embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Gridless solar cell; 11. Silicon substrate; 12. Fine grid; 13. First fine grid; 14. Second fine grid; 15. Fine grid unit; 2. Electrical connector; 21. Sub-connector; 22. Cross section; 24. Straight section; 3. Solar cell string. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] In this application, the terms "upper," "lateral," "longitudinal," etc., 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 this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0044] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0045] Furthermore, the terms "set up," "connect," and "link" 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 application based on the specific circumstances.

[0046] 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.

[0047] Gridless solar cells eliminate the main grid but increase the number of fine grids, while still using a continuous grid line layout. A continuous grid line refers to a grid line that is a single, continuous line. This layout ensures compatibility and maturity of the manufacturing process to some extent, but it also limits the full utilization of the solar cell's illuminated area. Although the continuous grid line layout can be improved to an array-type fine grid layout to reduce the shading area, each column of fine grids is still connected in series via an electrical connector. This means the number of electrical connectors is the same as the number of columns of fine grids, requiring a longer total length of connectors, which in turn leads to higher transmission resistance.

[0048] Based on the above analysis, in a gridless solar cell disclosed in this application embodiment, multiple first grids and multiple second grids in a grid cell can be connected in series through a section of electrical connector. That is, two rows of grids only need to be connected in series through a section of electrical connector, thereby optimizing the current transmission path and reducing the transmission resistance.

[0049] The technical solution of this utility model will be described below with reference to the embodiments and accompanying drawings.

[0050] Firstly, please combine Figures 1 to 4 This application discloses a gridless solar cell 1, including a silicon substrate 11 and a plurality of fine grids 12. The plurality of fine grids 12 are disposed on the surface of the silicon substrate 11 and arranged in multiple rows. The surface of the silicon substrate 11 refers to the light-receiving surface or the backlighting surface of the silicon substrate 11. The multiple rows of fine grids 12 are arranged side-by-side in a first direction, such as... Figure 1 and Figure 2The X0-X1 direction is shown. The arrangement direction of the fine grids 12 in each column is the second direction, as shown in the diagram. Figure 1 , Figure 2 and Figure 4 In the Y0-Y1 direction shown, the first direction and the second direction intersect. Every two adjacent columns of fine grids 12 form a group of fine grid units 15. The odd-numbered columns of fine grids 12 consist of multiple spaced first fine grids 13, and the even-numbered columns of fine grids 12 consist of multiple spaced second fine grids 14. It can be understood that each fine grid unit 15 necessarily includes a column of first fine grids 13 and a column of second fine grids 14.

[0051] In any set of fine gate units 15, the first fine gate 13 and the second fine gate 14 are alternately arranged in the second direction. The fine gate unit 15 is configured to alternately electrically connect the first fine gate 13 and the second fine gate 14 in the arrangement order in the second direction, so as to connect the first fine gate 13 and the second fine gate 14 one by one in sequence.

[0052] It should be noted that the odd-numbered columns of fine gates 12 can refer to the first, third, fifth, etc., columns of fine gates 12 in the first direction, and the even-numbered columns of fine gates 12 can refer to the second, fourth, sixth, etc., columns of fine gates 12 in the first direction. On the other hand, the alternating electrical connection of the first fine gates 13 and second fine gates 14 according to their arrangement in the second direction specifically means that, in the second direction, the first first fine gate 13 is connected to the first second fine gate 14, the first second fine gate 14 is connected to the second first fine gate 13, the second first fine gate 13 is connected to the second second fine gate 14, the second second fine gate 14 is connected to the third first fine gate 13, and so on, until the last first fine gate 13 and the last second fine gate 14 are connected. Thus, all the first fine gates 13 and second fine gates 14 in the same fine gate unit 15 are connected sequentially.

[0053] In this gridless solar cell 1, every two adjacent rows of fine grids 12 form a group of fine grid units 15. In any group of fine grid units 15, the first fine grid 13 and the second fine grid 14 are alternately arranged in the second direction. The fine grid units 15 employ this alternating arrangement of the first fine grid 13 and the second fine grid 14, allowing the fine grid units 15 to be electrically connected alternately to the first fine grid 13 and the second fine grid 14 according to their arrangement order in the second direction, thus connecting the first fine grid 13 and the second fine grid 14 sequentially. In other words, multiple first fine grids 13 and multiple second fine grids 14 in a single fine grid unit 15 can be connected in series through an electrical connector 2. That is, two rows of fine grids 12 only require one electrical connector 2 for series connection, thereby optimizing the current transmission path and reducing transmission resistance.

[0054] Further, see Figure 5The series lengths of the two columns of fine grids 12 in the fine grid unit 15 are L1 and L2, respectively. The shortest path for the fine grid unit 15 to sequentially connect the first and second fine grids is L3. Where L3 < L1 + L2. It should be noted that the series length of each column of fine grids 12 refers to the length of the electrical connector required to connect all the fine grids 12 in the same column, and this series length is equal to the distance between the two fine grids 12 at both ends of each column. On the other hand, the shortest path L3 is the shortest length of the required electrical connector 2. The shortest length electrical connector 2 is a broken line and includes multiple sequentially connected straight line segments 24. The shortest path between any two connected fine grids 12 is the straight-line distance L4 between the two fine grids 12, which is the length of the straight-line segment 24. In other words, the shortest path L3 is the sum of the lengths L4 of all straight-line segments 24 in each electrical connector 2. It is understandable that if each column of fine grids is connected in series through an electrical connector, the required length of the electrical connector would be at least L1 + L2. However, in this application, the two columns of fine grids 12 in a fine grid unit 15 only require one electrical connector 2 for series connection. The length of the electrical connector 2 is relatively shorter, i.e., L3 < L1 + L2, resulting in a smaller transmission resistance.

[0055] In some embodiments, see Figure 6 and Figure 7 The fine grid 12 can be dot-shaped or line-segment-shaped. Dot-shaped and line-segment-shaped grids can achieve both a lower light-blocking area and a better current collection effect.

[0056] like Figure 6 As shown, the fine grid 12 is in the shape of a dot. If the diameter of the fine grid 12 is less than 5 μm, it will increase the difficulty of printing the fine grid 12; if the diameter of the fine grid 12 is greater than 25 μm, it will result in a larger light-shielding area of ​​the fine grid 12. Preferably, the diameter of the fine grid 12 is 5 μm to 25 μm, including any point value within this diameter range, such as 5 μm, 15 μm, or 25 μm, which reduces the manufacturing difficulty and results in a smaller light-shielding area.

[0057] like Figure 7 As shown, the fine grid 12 is linear. The first direction is as follows: Figure 7 In the X0-X1 direction shown, if the size of the fine grid 12 is less than 0.01 mm in the first direction, the screen printing plate will easily suffer from insufficient strength, making it difficult to guarantee the lifespan of the screen. If the size of the fine grid 12 is greater than 10 mm, the light-blocking area is larger. Preferably, in the first direction, the size of the fine grid 12 is 0.01 mm to 10 mm, including any value within this range, such as 0.01 mm, 5 mm, or 10 mm, which can maintain the structural strength of the screen while having a smaller light-blocking area.

[0058] The second direction is as follows Figure 7As shown in the Y0-Y1 direction, in the second direction, if the size of the fine grid 12 is less than 10μm, the printing difficulty increases, making it difficult to manufacture a fine grid 12 that meets the requirements; if the size of the fine grid 12 is greater than 50μm, it will result in a larger light-shielding area of ​​the fine grid 12. Preferably, in the second direction, the size of the fine grid 12 is 10μm to 50μm, including any value within this size range, such as 10μm, 30μm, or 50μm, which has lower manufacturing difficulty and a smaller light-shielding area.

[0059] In some embodiments, such as Figure 6 and Figure 7 As shown, multiple fine gratings 12 are arranged in multiple rows, with the rows of fine gratings 12 spaced apart in a second direction. Each row of fine gratings 12 includes multiple fine gratings 12 spaced apart along a first direction, which is the X0-X1 direction, and the second direction is the Y0-Y1 direction. In two adjacent rows of fine gratings 12, one row of fine gratings 12 is a first fine grating, and the other row of fine gratings 12 is a second fine grating. In other words, the first fine grating array is arranged in multiple rows and columns, and the second fine grating array is arranged in multiple rows and columns.

[0060] Compared to a continuous grid layout, the fine grid 12 in this application is arranged in an array, with multiple rows and columns. Each row and column of fine grid 12 includes multiple spaced-apart fine grids 12. This layout of fine grid 12 makes it easier to design the current collection path, and the size of the fine grid 12 is relatively smaller, for example, shorter in length. The smaller size of the fine grid 12 can reduce the risk of failure of the gridless solar cell 1 due to breakage or poor welding of the fine grid 12, thereby improving the reliability and durability of the photovoltaic module.

[0061] Please combine Figure 6 and Figure 7 In the same row of fine grids 12, if the interval between two adjacent fine grids 12 is less than 0.6 mm, the fine grids 12 are too densely distributed, resulting in severe shading caused by light absorption and reflection, and requiring a large amount of silver paste to manufacture the fine grids 12. If the interval between two adjacent fine grids 12 is greater than 3 mm, the fine grids 12 are too sparsely distributed, resulting in poor current collection efficiency. Preferably, the interval D1 between two adjacent fine grids 12 is 0.6 mm to 3 mm, including any value within this range, such as 0.6 mm, 1 mm, or 3 mm. This achieves both good current collection efficiency and low shading area, requiring less silver paste to manufacture the fine grids 12 and reducing material costs. It should be noted that for dot-shaped fine grids 12, the interval between two fine grids 12 refers to the distance between the centers of the two fine grids. For linear fine grids 12, the interval between two fine grids 12 refers to the distance between the ends of the two fine grids closest to each other.

[0062] If the spacing between two adjacent rows of fine grids 12 is less than 0.5 mm, the fine grids 12 are too densely distributed, which will cause serious light shading and a large amount of silver paste used. It will also result in an excessively long electrical connector 2 required for all the fine grids 12 in a series fine grid unit 15, increasing the transmission resistance. If the spacing between two adjacent rows of fine grids 12 is greater than 2 mm, the fine grids 12 are too sparsely distributed, resulting in poor current collection. Preferably, the spacing D2 between two adjacent rows of fine grids 12 is 0.5 mm to 2 mm, including any value within this range, such as 0.5 mm, 1 mm, or 2 mm. This achieves both good current collection and a low shading area, and requires less silver paste to manufacture the fine grids 12.

[0063] Optionally, such as Figure 6 and Figure 7 As shown, the first direction and the second direction are perpendicular. For example, one of the first direction and the second direction is vertical, and the other is horizontal. That is, the fine gate 12 is distributed in a horizontal and vertical array, which makes it more uniformly distributed on the surface of the silicon substrate 11, which is beneficial for collecting current.

[0064] Secondly, please combine Figure 8 and Figure 9 This application discloses a solar cell string 3, comprising a plurality of gridless solar cells 1 as described in the first aspect and a plurality of electrical connectors 2. Each electrical connector 2 is alternately connected to a first fine grid 13 and a second fine grid 14 in a fine grid unit 15 according to an arrangement order in a second direction, so as to sequentially connect the first fine grid 13 and the second fine grid 14 one by one. The second direction is as follows: Figure 9 The Y0-Y1 direction is shown in the diagram.

[0065] In any group of fine grid units 15 of the gridless solar cell 1 in the solar cell string 3, the first fine grid 13 and the second fine grid 14 are alternately arranged in the second direction. The fine grid unit 15 employs this alternating arrangement of the first fine grid 13 and the second fine grid 14, allowing the fine grid unit 15 to alternately connect the first fine grid 13 and the second fine grid 14 according to their arrangement order in the second direction, connecting them sequentially. In other words, multiple first fine grids 13 and multiple second fine grids 14 in a fine grid unit 15 only require one electrical connector 2 for series connection; that is, two columns of fine grids 12 only require one electrical connector 2 for series connection. The number of electrical connectors 2 is half the number of columns of fine grids 12, and the total length of the electrical connectors 2 can be shorter, thereby optimizing the current transmission path and reducing transmission resistance.

[0066] Optionally, the gridless solar cell 1 is a passivated contact solar cell, a heterojunction solar cell, or a back contact solar cell. The electrical connector 2 is a solder strip.

[0067] Optionally, such as Figure 9As shown, the electrical connector 2 is zigzag-shaped and includes multiple sub-connectors 21 connected end-to-end in sequence. Each of the two connected grid cells 12 is connected by a sub-connector 21. This solar cell string 3 effectively connects the individual grid cells 12 using shorter sub-connectors 21, which not only optimizes the current transmission path but also significantly reduces the resistance during transmission. This improvement helps to increase the overall efficiency of the solar cell string 3.

[0068] Furthermore, such as Figure 10 As shown, two intersecting sub-connectors 21 are arranged crosswise, with the cross portion 22 located on the fine grid 12. Even if the fine grid 12 is offset during printing, the cross portion 22 of the two sub-connectors 21 can still connect with the offset fine grid 12, thereby allowing the fine grid 12 to have a larger graphic offset during printing and reducing the requirements for printing accuracy of the fine grid 12.

[0069] Optionally, such as Figure 11 As shown, the series lengths of two adjacent columns of fine grids 12 are L1 and L2, respectively, and the shortest length of the electrical connector 2 is L3. Where L3 < L1 + L2. It should be noted that, since the electrical connector 2 includes multiple sequentially connected sub-connectors 21, but portions of the sub-connectors 21 are not used to connect the fine grids 12, for example, if two sub-connectors 21 are arranged crosswise, the crosswise portion may not be used to connect the fine grids 12. Specifically... Figure 11 In the previous example, the length of the straight section of each sub-connector 21 used to connect the fine grid 12 is L4. Therefore, the shortest length L3 of the electrical connector 2 is the sum of the lengths L4 of the straight sections of all its sub-connectors 21. It can be understood that if each column of fine grids is connected in series via an electrical connector, the required length of the electrical connector would be at least L1 + L2. However, in this application, the two columns of fine grids 12 in a single fine grid unit 15 only require one electrical connector 2 for series connection. The total length of the electrical connector 2 is shorter, i.e., L3 < L1 + L2, resulting in lower transmission resistance.

[0070] For example, refer to the return Figure 9 The fine grid 12 is in the shape of a dot, and the center of the fine grid 12 is connected to the electrical connector 2 to make the connection between the fine grid 12 and the electrical connector 2 more reliable.

[0071] As another example, see Figure 12 The fine grid 12 is linear, and its length direction is in the same direction as the first direction, as shown in the figure. Figure 12 In the X0-X1 direction shown, in the first direction, the end of the fine gate 12 near the center of the fine gate unit 15 is connected to the electrical connector 2. The center of the fine gate unit 15 is the center of the two rows of fine gates 12 in the first direction. The purpose of the above design is to shorten the length of the electrical connector 2 between the two fine gates 12 and optimize the current transmission path.

[0072] Thirdly, embodiments of this application disclose a photovoltaic module, including a solar cell string as described in the second aspect.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A gridless solar cell, characterized in that, include: Silicon substrate; as well as Multiple fine gates are disposed on the surface of the silicon substrate and arranged in multiple columns. The multiple columns of fine gates are arranged side by side in a first direction. The arrangement direction of the fine gates in each column is a second direction. The first direction and the second direction intersect. The odd-numbered columns of fine gates are multiple first fine gates arranged at intervals, and the even-numbered columns of fine gates are multiple second fine gates arranged at intervals. Every two columns of adjacent fine gates form a group of fine gate units. In any group of fine gate units, the first fine gates and the second fine gates are alternately arranged in the second direction. The fine gate units are configured to alternately electrically connect the first fine gates and the second fine gates according to their arrangement order in the second direction, so as to connect the first fine gates and the second fine gates sequentially.

2. The gridless solar cell according to claim 1, characterized in that, The series lengths of the two columns of fine grids in the fine grid unit are L1 and L2, respectively; The fine gate unit is configured such that the shortest path connecting the first fine gate and the second fine gate sequentially is L3; where L3 < L1 + L2.

3. The gridless solar cell according to claim 1, characterized in that, The fine grid is in the form of dots or line segments.

4. The gridless solar cell according to claim 3, characterized in that, The fine grid is in the shape of round dots, and the diameter of the fine grid is 5μm to 25μm.

5. The gridless solar cell according to claim 3, characterized in that, The fine grid is linear, and in the first direction, the size of the fine grid is 0.01 mm to 10 mm; in the second direction, the size of the fine grid is 10 μm to 50 μm.

6. The gridless solar cell according to claim 1, characterized in that, Multiple fine grids are arranged in multiple rows, and the multiple rows of fine grids are spaced apart in the second direction. Each row of fine grids includes multiple fine grids spaced apart along the first direction. In two adjacent rows of fine grids, one row of fine grids is the first fine grid and the other row of fine grids is the second fine grid.

7. The gridless solar cell according to claim 6, characterized in that, In the same row of fine grids, the spacing between two adjacent fine grids is 0.6 mm to 3 mm; And / or, the spacing between two adjacent rows of the fine grid is 0.5 mm to 2 mm; And / or, the first direction and the second direction are perpendicular.

8. A solar cell string, characterized in that, include: Several gridless solar cells as described in any one of claims 1 to 7; as well as A plurality of electrical connectors, each of which is alternately connected to the first and second fine gates in a fine gate unit according to the arrangement order in the second direction, so as to connect the first and second fine gates sequentially.

9. The solar cell string according to claim 8, characterized in that, The electrical connector is zigzag-shaped and includes multiple sub-connectors connected end to end in sequence. Each of the two connected fine grids is connected by one of the sub-connectors. The two connected sub-connectors are arranged crosswise and the crosswise part is located on the fine grid. And / or, the series lengths of two adjacent columns of the fine grids are L1 and L2, respectively, and the shortest length of the electrical connector is L3; wherein, L3 < L1 + L2; And / or, the gridless solar cell is a passivated contact solar cell, a heterojunction solar cell, or a back contact solar cell; And / or, the fine grid is in the shape of a dot, and the center of the fine grid is connected to the electrical connector; And / or, the fine grid is linear, the length direction of the fine grid is in the same direction as the first direction, and in the first direction, one end of the fine grid near the center of the fine grid unit is connected to the electrical connector; And / or, the electrical connector is a solder strip.

10. A photovoltaic module, characterized in that, Includes the solar cell string as described in claim 8 or 9.

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