Solar cell and photovoltaic module

Abstract

Solar cell, characterized in that it comprises the following: a substrate; a doped layer that is arranged on the surface of the substrate; a first functional membrane that is arranged on a surface of the doped layer facing away from the substrate; several sublattices, each arranged on the first functional membrane and penetrating the first functional membrane to establish an ohmic contact with the doped layer; wherein the longitudinal direction of the sublattice is a first direction, and wherein the several sublattices are arranged in a row at intervals along the first direction; and wherein within the same row of sublattices there is an intermediate section between each pair of adjacent sublattices; several connecting grid lines arranged on one side of the first functional membrane facing away from the doped layer and embedded in a portion of the thickness of the first functional membrane; and wherein a connecting grid line is arranged in each intermediate section, and wherein, in the first direction, the connecting grid line is connected between two sublattices on both sides of the intermediate section; and a main grid located at the first functional membrane and extending along a second direction, the second direction intersecting with the first direction, and the main grid intersecting with the connecting grid line or sublattice to electrically connect a series of sublattices.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of solar cells, in particular a solar cell and a photovoltaic module. STATE OF THE ART

[0002] The subgrids of solar cells are continuous structures of considerable length. The length of a single subgrid is only slightly smaller than the dimensions of the solar cell itself. Such continuous subgrids necessitate the inclusion of printing holes in the screen printing sheet, the length of which corresponds to the length of the printing screen sheet. Longer printing holes compromise the structural strength of the screen printing sheet and thus reduce its lifespan. CONTENTS OF THE PRESENT USE SAMPLE

[0003] An embodiment of the present application discloses a solar cell and a photovoltaic module which advantageously makes it possible to use a screen printing sheet with a high openness ratio for printing subgrids with a small line width, wherein the screen printing sheet simultaneously has a longer service life and higher structural strength, and the printed subgrids ensure improved current collection and electrical conductivity.

[0004] To achieve the above-mentioned objectives, an embodiment of the present application discloses in the first aspect a solar cell comprising the following: a substrate; a doped layer that is arranged on the surface of the substrate; a first functional membrane that is arranged on a surface of the doped layer facing away from the substrate; several sublattices, each arranged on the first functional membrane and penetrating the first functional membrane to establish an ohmic contact with the doped layer; wherein the longitudinal direction of the sublattices is a first direction, and wherein the several sublattices are arranged in a row at intervals along the first direction; and wherein within the same row of sublattices there is an intermediate section between each pair of adjacent sublattices; several connecting grid lines arranged on one side of the first functional membrane facing away from the doped layer and embedded in a portion of the thickness of the first functional membrane; and wherein a connecting grid line is arranged in each intermediate section, and wherein, in the first direction, the connecting grid line is connected between two sublattices on both sides of the intermediate section; and a main grid located at the first functional membrane and extending along a second direction, the second direction intersecting with the first direction, and the main grid intersecting with the connecting grid line or sublattice to electrically connect a series of sublattices.

[0005] In one embodiment in the first aspect, the sublattices comprise several rows, wherein the several rows of sublattices are arranged at intervals in the second direction, and wherein each main lattice overlaps with the several rows of sublattices; wherein among the several sublattices that overlap with the same main lattice, two adjacent sublattices are partially offset in the first direction.

[0006] In one embodiment, in the first aspect, several main grids are provided, wherein the several main grids are arranged at intervals in the first direction; wherein the orthogonal projection of a single sublattice in a row of two adjacent rows of sublattices overlaps in the second direction with the orthogonal projections of several sublattices in the other row in the second direction and forms an overlapping region with them, and wherein the sublattices lying in the overlapping region intersect with the principal lattices.

[0007] In one embodiment in the first aspect, when the main lattice overlaps with the sublattice, the sublattice has several sublattice overlap segments, each sublattice overlap segment being located at the intersection point between the sublattice and the respective main lattice.

[0008] In one embodiment in the first aspect, several main lattice overlap lines are further arranged on the main lattice, wherein each main lattice overlap line is located at the intersection between the main lattice and the respective sublattice, and wherein each main lattice overlap line is at least partially stacked with the respective sublattice overlap segment.

[0009] In one embodiment in the first aspect, the dimension of the sublattice overlap segment in the second direction is the width; wherein in the first direction the central part of the sublattice overlap segment overlaps with the main lattice, and wherein the width of the sublattice overlap segment decreases from the center to both ends; and wherein the width at the widest point of the sublattice overlap segment is W1; and wherein in each sublattice the width of the section outside the sublattice overlap segment is W2, and wherein W1 > W2; and wherein the dimension of the main grid overlap segment in the second direction is the width; and wherein in the first direction the middle part of the main grid overlap line overlaps with the main grid, and wherein the width of the main grid overlap line decreases from the center to both ends; and wherein the width at the widest point of the main grid overlap line is W4, and wherein W4 > W2.

[0010] In one embodiment, in the first aspect, the width W1 at the widest point of the subgrid overlap segment is 30 µm to 80 µm; and / or wherein the width W2 of the section of each sublattice other than the sublattice overlap segment is 8 µm to 30 µm; and / or wherein the width W3 at the narrowest point of the subgrid overlap segment is 8 µm to 30 µm; and / or wherein the width W4 at the widest point of the main lattice overlap line is 30 µm to 80 µm; and / or wherein the width W5 at the narrowest point of the main lattice overlap line is 8 µm to 30 µm; and / or wherein the length L1 of the subgrid overlap segment in the first direction is 0.3 mm to 2 mm; and / or wherein the length L2 of the main grid overlap line in the first direction is 0.3 mm to 2 mm.

[0011] In one embodiment, in the first aspect, the pattern of the connecting grid line is either a solid pattern or a hollow pattern.

[0012] In one embodiment, in the first aspect, the shape of the connecting grid line is symmetrical or asymmetrical.

[0013] In one embodiment, in the first aspect, if the shape of the connecting grid line is symmetrical, the connecting grid line is rectangular, square, circular, I-shaped, triangular or straight; where, if the shape of the connecting grid line is asymmetrical, the connecting grid line has the shape of a wavy line, an asymmetrical triangle, or a right-angled shape.

[0014] In one embodiment in the first aspect, the substrate has a dimension D1 in the first direction, wherein the length of a single subgrid is L3 and L3 / D1=3%-20%.

[0015] In one embodiment in the first aspect, in at least one series of sublattices, the total length of all sublattices L4 and the distance between the two ends of this series of sublattices in the first direction D2 are, where L4 / D2=95%-99%; and / or wherein the substrate has a dimension D1 in the first direction, and wherein the width of a single intermediate section in the first direction is W7, and wherein W7 / D1 = 0.1% - 1.1%.

[0016] In one embodiment, in the first aspect, the length L3 of a single subgrid in the first direction is 5.4 mm to 42 mm; and / or wherein the width W7 of a single intermediate section in the first direction is 0.2 mm to 2 mm; and / or wherein the dimension D3 of the connecting grid line in the second direction is 0.02 µm to 0.3 µm; and / or wherein the dimension D4 of the connecting grid line in the first direction is 0.2 mm to 2 mm; and / or where the first direction is perpendicular to the second direction.

[0017] In a second aspect, an embodiment of the present application discloses a photovoltaic module comprising several solar cells connected in series and / or parallel, wherein at least one solar cell is the solar cell in the first aspect.

[0018] Compared to the prior art, the present application has at least the following advantageous effects: In the embodiment of the present application, several subgrids are spaced apart from one another in a row along the first direction. Within the same row of subgrids, an intermediate segment is located between each pair of adjacent subgrids. It is understood that at least one row of subgrids in the embodiment of the present application has a discontinuous structure. Related technologies use a single continuous, long subgrid for current collection, the length of such a subgrid often being only slightly smaller than the dimensions of the solar cell along the longitudinal direction of the subgrid. In contrast, the solar cell of the present application uses several discontinuous, shorter subgrids arranged in a row to collect current. The length of the subgrids in the present application can be considerably smaller than the dimensions of the solar cell in the first direction.

[0019] Accordingly, the subgrid printing holes on the screen printing sheet, through which these subgrids are printed, also exhibit a discontinuous structure and shorter lengths. Since the subgrid printing holes are formed by removing material from the open areas of the screen printing sheet, they represent weak points on the sheet. Therefore, shorter subgrid printing holes result in shorter weak points on the screen printing sheet, thus improving the structural strength of the screen printing sheet. Particularly with high-open-ratio screen printing sheets, the improvement in structural strength is more pronounced the shorter the length of the subgrid printing holes.This allows the solar cell to achieve cost reduction and efficiency increase by printing the subgrids with a smaller line width over the high open-ratio screen printing sheet, while the high open-ratio screen printing sheet itself has high structural strength and a longer lifespan.

[0020] Based on this, the present application provides connecting grid lines within each intermediate section to link the multiple interrupted subgrids into a continuous configuration. In the first direction, these connecting grid lines link two adjacent subgrids on either side of the intermediate section. In other words, the connecting grid lines link two interrupted subgrids into a continuous arrangement. Accordingly, a series of interrupted subgrids can be connected into a continuous configuration via a plurality of connecting grid lines, thereby improving the current collection effect and the continuity of current transmission of this series of subgrids.To reduce the effects of the bonding grid lines on the first functional membrane, the bonding grid lines are arranged on the side of the first functional membrane facing away from the doped layer and embedded in a portion of the thickness of the first functional membrane, and the bonding grid lines do not penetrate the first functional membrane, namely, these bonding grid lines cause only minor damage to the first functional membrane, this facilitates the maintenance of the structural integrity of the first functional membrane, reduces compounding phenomena and contributes to improving the conversion efficiency of the solar cell.

[0021] In summary, the solar cell uses a design with at least one series of subgrids in a discontinuous configuration. This facilitates cost reduction and increased efficiency by allowing the subgrids to be printed with a narrower line width using a high-aperture screen sheet. Simultaneously, this high-aperture screen sheet offers superior structural strength and a longer lifespan. Furthermore, connecting at least one series of subgrids into a continuous configuration via the connecting grid lines improves current collection and the continuity of current transfer within that series of subgrids. These connecting grid lines cause minimal damage to the first functional membrane, further enhancing the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWING

[0022] To clarify the technical solution in the embodiments of the present application, the figures to be used in the explanation of the embodiments are briefly introduced below. Obviously, the drawings described below show only some embodiments of the present application. The person skilled in the art in this field can, provided no creative work is undertaken, derive other drawings from the accompanying drawings. Fig. Figure 1 shows a schematic diagram of the structure of a solar cell provided by an embodiment of the present application. Fig. Figure 2 shows a partially enlarged view of the in Fig. 1 of the area shown I. Fig. Figure 3 shows an AA sectional view according to Fig. 2. Fig. Figure 4 shows a BB section view according to Fig. 2. Fig. Figure 5 shows a CC section view according to Fig. 2. Fig. Figure 6 shows another partially enlarged view of the in Fig. 1 of the area shown I. Fig. Figure 7 shows a schematic diagram of the structure of a subgrid screen printing sheet provided by an embodiment of the present application. Fig. Figure 8 shows a schematic diagram of several subgrids intersecting with the same main lattice, as disclosed in an embodiment of the present application. Fig. Figure 9 shows a schematic diagram of the connection between two adjacent rows of subgrids and the main lattice, as disclosed in an embodiment of the present application. Fig. Figure 10 shows a partially enlarged view of the in Fig. 9 depicted area II. Fig. Figure 11 shows another partially enlarged view of the in Fig. 9 depicted area II. Fig. Figure 12 shows another schematic diagram of the structure of a solar cell provided by an embodiment of the present application. Fig. Figure 13 shows a schematic diagram of the structure of a series of subgrids provided by an embodiment of the present application. Fig. Figure 14a shows a schematic diagram of a variant structure of a connecting grid line provided by an embodiment of the present application. Fig. Figure 14b shows another schematic diagram of a variant structure of a connecting grid line provided by an embodiment of the present application. Fig. Figure 14c shows another schematic diagram of a variant structure of a connecting grid line provided by an embodiment of the present application. Fig. Figure 15 shows a schematic diagram of the structure of a photovoltaic module provided by an embodiment of the present application. Reference symbol list 10 solar cells 11 Substrat 12 Doped layer 13a First functional membrane 13b Second functional membrane 14 lower grids 141 Intermediate section 142 Subgrid overlap segment 143 Subgrid main body segment 15 Connecting grid line 16 main grids 161 Main grid overlap line 17 Medium layer 18 Doped polycrystalline silicon layer 19 Grid line electrode X First direction Y Second direction 20 lower grid screen printing sheets 21 Lower grid pressure opening 22 Separation area 30 Electrical connectors. DETAILED DESCRIPTION

[0023] In conjunction with the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application are explained clearly and completely below. Obviously, the described embodiments do not represent all embodiments, but only a subset. All other embodiments that a person skilled in the art in this field could obtain from the embodiments in the present application without any creative work should be considered to be covered by the scope of protection of the present application.

[0024] In this application, the terms “inside” and “outside” denote directional or positional relationships based on the orientation shown in the accompanying drawings. These terms primarily serve to better describe the present application and its embodiments and should not restrict the specified devices, elements, or components to necessarily having a particular orientation or being designed and operated in a particular orientation.

[0025] Furthermore, certain terms may have additional meanings beyond indicating orientation or positional relationships. For example, the term "above" may, in some contexts, denote a fastening or connecting relationship. The average person skilled in the art in this field can understand the specific meanings of the aforementioned terms in the present application based on the specific situations.

[0026] Furthermore, the terms “provided for”, “equipped with”, and “connected” should be interpreted broadly. They may, for example, denote fixed connections, detachable connections, or integral constructions; mechanical connections or electrical connections; direct connections, indirect connections via intermediate media, or internal communication between two devices, elements, or components. The person skilled in the art in this field will be able to understand the specific meanings of the foregoing terms in the present application based on the specific situations.

[0027] Furthermore, the terms "first," "second," etc., are primarily used to distinguish between different devices, elements, or components (whose specific types and designs may be identical or different) and should not indicate or imply the relative importance or quantity of the devices, elements, or components mentioned. Unless otherwise specified, "several" means two or more.

[0028] One way to reduce the cost and increase the efficiency of solar cells is to decrease the line width of the subgrid. This reduces the overall shaded area of ​​the subgrid and the wet weight of the paste during the printing process. The reduced shaded area allows the solar cell to absorb more light, thus improving its conversion efficiency. Reducing the wet weight of the paste also reduces paste consumption, which in turn lowers the production costs of the solar cell.

[0029] Printing subgrids with a smaller line width is difficult with steel wire screen sheets. This is because steel wire screen sheets are made of steel mesh woven from steel wires. Therefore, the printing openings in the steel wire screen sheet contain steel wires, limiting the open-pass ratio to approximately 80%. The steel wires in these printing openings impede the penetration of the paste. When steel wire screen sheets are used to print narrower subgrids, the poor paste permeability often leads to printing defects, resulting in subgrids with inferior morphology. In other words, steel wire screen sheets are unsuitable for printing subgrids with smaller line widths and thus hinder efforts to improve the conversion efficiency of solar cells by reducing subgrid line widths.

[0030] High-openness screen printing sheets, such as fully open steel wire mesh sheets, are better suited for printing subgrids with a smaller line width. This is because these sheets leave almost no material residue in the openings when the printing holes are formed, whereas steel wire mesh sheets only remove a portion of the material when slitting, leaving steel wires behind in the openings. In other words, high-openness screen printing sheets have a higher openness ratio than steel wire mesh sheets, and high-openness screen printing sheets can achieve 90%-100% (including endpoints), and the openness ratio can be measured with a screen tester. The printing holes on high-openness screen printing sheets have minimal or no obstruction.Therefore, the paste encounters less resistance when passing through these pressure openings, resulting in superior paste permeability.

[0031] However, since the printing apertures of the high-openance-ratio screen printing sheet lack structural elements such as steel wires to provide tensile reinforcement, it is understandable that the structural strength of the high-openance-ratio screen printing sheet is significantly compromised if the printing apertures are excessively long. Furthermore, to optimize current transmission, the subgrid pattern of solar cells is a continuous linear subgrid whose length is approximately equal to that of the substrate. Accordingly, the printing aperture for this linear subgrid is also a linear aperture with a length approximately equal to the dimensions of the screen printing sheet. Excessively long apertures lead to a reduction in the structural strength of the screen printing sheet.Furthermore, the absence of steel wires in the high-openance screen printing sheet, which serve to stretch the paper, means that the printing apertures are prone to deformation when pressure is applied by the scraper. This can lead to shifts in the printing position and an enlargement of the apertures, resulting in printing anomalies such as misalignments and coarse grids. These anomalies increase in frequency and severity with increasing length of the printing apertures.

[0032] Based on the above analysis, an embodiment of the present application provides a solar cell in which at least one series of subgrids is designed in a discontinuous configuration. This facilitates cost reduction and efficiency improvement of the solar cell by printing the subgrids with a smaller line width using a high-openance screen printing sheet. Simultaneously, this high-openance screen printing sheet offers superior structural strength and a longer service life. Furthermore, connecting at least one series of subgrids into a continuous configuration via the connecting grid lines improves the current collection effect and the continuity of current transfer within this series of subgrids. These connecting grid lines cause only minimal damage to the first functional membrane, thereby further improving the conversion efficiency of the solar cell.

[0033] In connection with exemplary embodiments and accompanying drawings, the technical solutions of the present utility model are explained in more detail below.

[0034] In a first aspect, as in Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Figure 5 shows an embodiment of the present application, which discloses a solar cell 10 comprising a substrate 11, a doped layer 12, a first functional membrane 13a, several subgrids 14, several connecting grid lines 15 and a main grid 16.

[0035] The doped layer 12 is arranged on the surface of the substrate 11. The first functional membrane 13a is arranged on a surface of the doped layer 12 facing away from the substrate 11.

[0036] Each sublattice 14 is arranged on the first functional membrane 13a and penetrates the first functional membrane 13a to establish an ohmic contact with the doped layer 12. The longitudinal direction of the sublattice 14 is a first direction, with the multiple sublattices 14 arranged in a row at intervals along the first direction X. Within the same row of sublattices 14, an intermediate segment 141 is located between each pair of adjacent sublattices 14.

[0037] The connecting grid lines 15 are arranged on one side of the first functional membrane 13a facing away from the doped layer 12 and are embedded in a portion of the thickness of the first functional membrane 13a. One connecting grid line 15 is arranged in each intermediate section 141, with the connecting grid line 15 in the first direction X being connected between two sublattices 14 on the two sides of the intermediate section 141.

[0038] The main grid 16 is arranged on the first functional membrane 13a and extends along the second direction Y, with the second direction Y intersecting with the first direction X, and with the main grid 16 intersecting with the connecting grid line 15 or the sublattice 14 to electrically connect a series of sublattices 14.

[0039] Optionally, the first direction X is perpendicular to the second direction Y. Of course, the angle between the first direction X and the second direction Y can also deviate slightly from 90°. For example, the angle between the first direction X and the second direction Y can also be 80°, 85°, 89°, 91°, 95° or 100°, and the embodiments of the present application are not limited thereto.

[0040] It should be noted that the doped layer 12, the first functional membrane 13a, the multiple subgrids 14, the connecting grating lines 15 and the main grating 16 in the present application can be arranged either on the light-receiving surface or the light-shielding surface of the substrate 11 without any restriction being imposed by the embodiments of the present application.

[0041] The beneficial effects of solar cell 10 are described in detail below.

[0042] In the embodiment of the present application, several subgrids 14 are spaced apart from one another in a row along the first direction X. Within the same row of subgrids 14, an intermediate section 141 is located between each pair of adjacent subgrids 14. It is understood that at least one row of subgrids 14 in the embodiment of the present application has a discontinuous structure. Related technologies use a single continuous, long subgrid for current collection, the length of such a subgrid often being only slightly smaller than the dimensions of the solar cell along the longitudinal direction of the subgrid. In contrast, the solar cell 10 of the present application uses several discontinuous, shorter subgrids 14 arranged in a row to collect current.The length of the subgrids 14 in the present application can be considerably smaller than the dimensions of the solar cell 10 in the first direction X.

[0043] Accordingly, with reference to Fig. 7. At least one series of subgrid pressure openings 21 with a discontinuous structure are formed on the subgrid screen printing sheet 20. A separation area 22 is formed between two adjacent subgrid pressure openings 21, with each individual subgrid pressure opening 21 being relatively short. Since the subgrid pressure openings 21 are formed by removing material from the opening areas of the subgrid screen printing sheet 20, they represent weak points on the subgrid screen printing sheet 20. Therefore, shorter subgrid pressure openings 21 result in shorter weak points on the subgrid screen printing sheet 20, thereby improving the structural strength of the subgrid screen printing sheet 20.Particularly with subgrid screen printing sheets 20 with a high open-ratio (open-ratio of 90%-100%), the improvement in the structural strength of the subgrid screen printing sheet 20 with a high open-ratio is more pronounced the smaller the length of the subgrid printing apertures 21. This allows the solar cell to achieve cost reduction and increased efficiency by printing the subgrids with a smaller line width on the subgrid screen printing sheet 20 with a high open-ratio, while the subgrid screen printing sheet 20 itself exhibits high structural strength and a longer service life.

[0044] Based on this, the present application provides connecting grid lines 15 within each intermediate section 141 to connect the multiple interrupted subgrids 14 into a continuous configuration. In the first direction X, these connecting grid lines 15 connect two adjacent subgrids 14 on either side of the intermediate section 141. In other words, the connecting grid lines 15 connect two interrupted subgrids 14 into a continuous arrangement. Accordingly, a series of interrupted subgrids 14 can be connected to a continuous configuration via a plurality of connecting grid lines 15, thereby improving the current collection effect and the continuity of current transmission of this series of subgrids 14.To reduce the effects of the bonding grid lines 15 on the first functional membrane 13a, the bonding grid lines 15 are arranged on a side of the first functional membrane 13a facing away from the doped layer 12 and are embedded in a part of the thickness of the first functional membrane 13a, and the bonding grid lines 15 do not penetrate the first functional membrane 13a, namely these bonding grid lines 15 cause only slight damage to the first functional membrane 13a, this facilitates the maintenance of the structural integrity of the first functional membrane 13a, reduces compounding phenomena and contributes to improving the conversion efficiency of the solar cell 10.

[0045] In summary, the solar cell 10 uses a design with at least one series of subgrids 14 in a discontinuous configuration. This facilitates cost reduction and efficiency improvement by allowing the subgrids 14 to be printed with a smaller line width using a high-aperture-ratio subgrid screen sheet. Simultaneously, this high-aperture-ratio subgrid screen sheet offers superior structural strength and a longer lifespan. Furthermore, connecting at least one series of subgrids 14 in a continuous configuration via the connecting grid lines 15 improves current collection and the continuity of current transmission within this series of subgrids 14. These connecting grid lines 15 cause only minimal damage to the first functional membrane 13a, thereby further improving the conversion efficiency of the solar cell 10.

[0046] The substrate 11, the doped layer 12 and the first functional membrane 13a are described in more detail below.

[0047] With reference to Fig. 3, Fig. 4 to Fig. 5. The substrate 11 can be an N-type silicon substrate or a P-type silicon substrate. The doped layer 12 can be a diffusion layer, for example, a boron diffusion layer or a phosphorus diffusion layer. The doped layer 12 can also be an N-doped polycrystalline silicon layer or a P-doped polycrystalline silicon layer. The first functional membrane 13a can be a passivation film and / or an antireflection film. The material of the first functional membrane 13a can be silicon nitride, silicon oxynitride, silicon oxide, or aluminum oxide.

[0048] For example, the cell type of solar cell 10 can be a passivated contact solar cell. When the doped layer 12 and the first functional membrane 13a are arranged on the light-receiving surface of the substrate 11, the solar cell 10 further comprises a medium layer 17, a doped polycrystalline silicon layer 18, and a second functional membrane 13b. The medium layer 17, the doped polycrystalline silicon layer 18, and the second functional membrane 13b are stacked sequentially on the light-shielding surface of the substrate 11, facing away from the substrate 11. The conductivity type of the doped polycrystalline silicon layer 18 is opposite to that of the doped layer 12. The second functional membrane 13a can be a passivation film and / or an antireflection film. The material of the second functional membrane 13b can be silicon nitride, silicon oxynitride, silicon oxide, or aluminum oxide.The material of the medium layer 17 can be at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide and titanium oxide.

[0049] It should be noted that a grid line electrode 19 can also be arranged on the surface of a side of the substrate 11 facing away from the sublattice 14. For example, if the sublattice 14 is arranged on the light-receiving surface of the substrate 11, the light-shielding surface of the substrate 11 can additionally have a grid line electrode 19, which may be arranged on the second functional membrane 13b.

[0050] Other examples of solar cells include other types of crystalline silicon solar cells, such as heterojunction solar cells or back-contact solar cells.

[0051] The subgrid and the main grating are described in detail below.

[0052] In some embodiments, the subgrids comprise 14 with reference to Fig. 6, Fig. 7 to Fig. 8 multiple rows, wherein the multiple rows of subgrids 14 are arranged at intervals in the second direction Y, and wherein each main lattice 16 overlaps with the multiple rows of subgrids 14. Among the multiple subgrids 14 that overlap with the same main lattice 16, two adjacent subgrids 14 are partially offset in the first direction X.

[0053] It should be noted that, for the sake of clarity, in Fig. 6. The intermediate section 141 represents the boundary between two adjacent subgrids 14 within the same row. That is, within the same row, a subgrid 14 separates each pair of adjacent intermediate sections 141.

[0054] Accordingly, as in Fig. Figure 7 shows that the two subgrid printing openings 21 for printing these two subgrids 14 on the subgrid screen printing sheet 20 are also partially offset. As analyzed above, the subgrid printing openings 21 create weak points on the subgrid screen printing sheet 20. In other words, the aforementioned design allows the two adjacent weak points of the subgrid screen printing sheet 20 to be offset, thus avoiding an excessive concentration of weak points. This ensures a relatively uniform structural strength across all positions of the subgrid screen printing sheet 20, further improving the structural strength and service life of the subgrid screen printing sheet 20.

[0055] On this basis, several main grids 16 in the embodiment of the present application are defined with reference to the Fig. 6 and Fig. 9 is provided, wherein the multiple principal grids 16 are arranged at intervals in the first direction X. The orthogonal projection of a single subgrid 14 in a row of two adjacent rows of subgrids 14 in the second direction Y overlaps with the orthogonal projections of multiple subgrids 14 in the other row in the second direction Y and forms an overlapping region with them, the subgrids 14 lying in the overlapping region intersecting with the principal grids 16.

[0056] For example, overlaps, as in Fig. Figure 9 shows the orthogonal projection of a single sublattice 14 in a row of two adjacent rows of sublattices in the second direction Y with the orthogonal projections of two sublattices 14 in the other row in the second direction Y and forms an overlapping region with these, the sublattices 14 lying in the overlapping region intersecting with the main lattices 16.

[0057] In summary, if two adjacent subgrids 14 are partially offset in the first direction X, additional subgrids 14 are arranged within the offset region of the subgrid 14. This arrangement ensures that the orthogonal projection of a single subgrid 14 in the second direction Y overlaps with the orthogonal projections of several subgrids 14 in another row in the second direction Y, thus forming an overlapping region. This design allows for a more uniform distribution of the subgrids 14 across the surface of the solar cell 10, thereby facilitating current collection from the surface of the solar cell 10.

[0058] Since the current from the sublattice 14 must be transferred to and collected by the main grid 16, an offset arrangement of the sublattice 14 can result in one end being too far from the main grid 16, leading to an excessively long current transfer path. To remedy this, in the embodiment of the present application, a single sublattice 14 overlaps with several main grids 16, with each intersection point between a sublattice 14 and a main grid 16 acting as a current collection point. In other words, multiple current collection points are distributed along a single sublattice 14, ensuring that the distance from each point of this sublattice 14 to the main grid 16 is relatively short. This means that the current transfer path from each point of this sublattice 14 is also relatively short.Since the transmission loss of the subgrid 14 is proportional to the length of the current transmission path, the intersection of the subgrid 14 with several main grids 16 offers the advantage of low transmission loss.

[0059] It should be noted that the aforementioned “single subgrid14” does not refer exclusively to a specific subgrid14. That is to say, it is not the case that only one subgrid14 can overlap with several main gratings16.

[0060] In some embodiments, as in Fig. 9 and Fig. 10 shown, when the main lattice 16 overlaps with the sublattice 14, the sublattice 14 has several sublattice overlap segments 142, each sublattice overlap segment 142 being located at the intersection point between the sublattice 14 and the respective main lattice 16.

[0061] The solar cell 10 includes subgrid overlap segments 142 at the intersections between the subgrid 14 and the main grid 16. These subgrid overlap segments 142 improve the connection efficiency between the subgrid 14 and the main grid 16. The subgrid overlap segments 142 can be printed simultaneously with the subgrid 14, thus eliminating the need for additional printing processes. Since the paste used to print the subgrid 14 has a higher solids content, the printed subgrid overlap segments 142 contain a correspondingly larger amount of electrode material (e.g., silver). This makes it easier for the subgrid overlap segments 142 to inhibit corrosion reactions caused during solder tape welding.

[0062] It should be noted that the presence of a sublattice overlap segment 142 on at least one sublattice 14 is sufficient. The number of sublattice overlap segments 142 on a single sublattice 14 can be one or more without any limitation being imposed by the embodiments of the present application.

[0063] More precisely, the aforementioned paste refers to the paste used for printing grid-line electrodes, such as metal pastes, including silver paste, silver-aluminum paste, or silver-coated copper paste. The aforementioned etching reaction refers to the corrosion reaction caused by the solder tape material on the electrode material, such as silver etching. Silver etching describes the reaction between the tin-based alloy on the solder tape surface and the silver in the electrode material being soldered, thereby reducing the silver content in the electrode material.

[0064] In the embodiment of the present application, the dimension of the sublattice overlap segment 142 in the second direction Y is the width, wherein the width at the widest point of the sublattice overlap segment 142 is W1. Optionally, the width of the section of each sublattice 14 other than the sublattice overlap segment 142 is W2, where W1 > W2.

[0065] For better understanding, the section of the subgrid 14, excluding the subgrid overlap segment 142, will be referred to below as the subgrid main body segment 143. If the width at the widest point of the subgrid overlap segment 142 satisfies the condition W1 > W2, this means that the subgrid overlap segment 142 uses a larger volume of paste material during printing compared to the subgrid main body segment 143, thus achieving a greater width. This means that the subgrid overlap segment 142 contains a higher amount of electrode material. When soldering the main grid 16 to the solder tape, the subgrid overlap segment 142, which contains more electrode material, can better withstand the corrosive reaction of the solder tape. This improves the solder fracture strength of the subgrid overlap segment 142, thereby reducing the fracture rate of the subgrid 14.Therefore, it improves the current collection capacity of solar cell 10, which in turn contributes to improving the conversion efficiency of solar cell 10.

[0066] Optionally, the width W1 at the widest point of the subgrid overlap segment 142 is 30 µm to 80 µm and includes any value within this width range, for example, 30 µm, 50 µm, or 80 µm. If the width W1 at the widest point of the subgrid overlap segment 142 is within the aforementioned width range, the width at the widest point of the subgrid overlap segment 142 is sufficiently large. The solder break strength of the subgrid overlap segment 142 is directly proportional to its width, meaning that the solder break strength at the widest point of the subgrid overlap segment 142 is improved.Furthermore, the subgrid overlap segment 142 can avoid excessive light blocking area and excessive consumption of printing paste caused by excessive line width, meaning that the light blocking area of ​​this subgrid overlap segment 142 is small and the wet weight of the paste during printing is low.

[0067] Optionally, the width W2 of the section of each subgrid 14, except for the subgrid overlap segment 142, is 8 µm to 30 µm and includes any value within this width range, for example, 8 µm, 20 µm, or 30 µm. If the width W2 of the subgrid main body segment 143 is within the aforementioned range, this indicates a smaller width of the subgrid main body segment 143. This results in a reduction of the light-blocking area and lower paste consumption during printing, contributing to cost reduction and increased efficiency for the solar cell 10. Furthermore, the subgrid main body segment 143 can exhibit increased resistivity and printing anomalies caused by an excessively small width, meaning that the subgrid main body segment 143 has a lower resistivity and improved printing morphology.

[0068] Furthermore, the central part of the sublattice overlap segment 142 overlaps with the main lattice 16 in the first direction X, with the width of the sublattice overlap segment 142 decreasing from the center to both ends. In other words, the widest point of the sublattice overlap segment 142 is its central part, while the narrowest points of the sublattice overlap segment 142 are its two ends along the first direction X.

[0069] Since the solder tape is placed over the main grid 16 during the soldering process, the central part of the subgrid overlap segment 142 overlaps with the main grid 16, thus facilitating contact with the solder tape, while the two ends of the subgrid overlap segment 142 are less accessible to the solder tape. Therefore, the subgrid overlap segment 142 utilizes its widest point to overlap with the main grid 16, ensuring that the section at the point where the subgrid overlap segment 142 easily makes contact with the solder tape contains a greater amount of electrode material, thereby improving the solder joint strength.The narrowing of the two ends of the subgrid overlap segment 142 reduces the light-blocking area of ​​the subgrid overlap segment 142 and lowers the wet weight of the paste during the printing process, which contributes to cost reduction and efficiency improvement for the solar cell 10.

[0070] For example, the narrowing of the sublattice overlap segment 142 can be achieved by a gradual narrowing. For instance, the central part of the sublattice overlap segment 142 can have a square configuration with trapezoidal extensions at both ends. This arrangement results in a uniform width in the central part of the sublattice overlap segment 142, while the extension sections at both ends of the sublattice overlap segment 142 narrow. Alternatively, the sublattice overlap segment 142 can have a rhombic configuration. Of course, the narrowing of the sublattice overlap segment 142 can also be achieved by a stepped configuration, in which the two ends of the sublattice overlap segment 142 have a stepped shape.

[0071] Optionally, the width W3 at the narrowest point of the sublattice overlap segment 142 is 8 µm to 30 µm and includes any value within this width range, for example, 8 µm, 20 µm, or 30 µm. If the width W3 at the narrowest point of the sublattice overlap segment 142 meets the aforementioned width range, the narrowest point of the sublattice overlap segment 142 is sufficiently narrow to result in a smaller light-blocking area and reduced paste consumption. Furthermore, the sublattice overlap segment 142 can avoid the increased resistivity and printing anomalies caused by an excessively small width, meaning that the sublattice overlap segment 142 exhibits lower resistivity and improved printing morphology.

[0072] Optionally, the length L1 of the subgrid overlap segment 142 in the first direction X is 0.3 mm to 2 mm, encompassing any value within this length range, for example, 0.3 mm, 1 mm, or 2 mm. If the length L1 of the subgrid overlap segment 142 in the first direction X is within the aforementioned length range, the subgrid overlap segment 142 is of sufficient length. This ensures that even if the solder strip shifts, it can still make contact with the wider subgrid overlap segment 142, thereby improving the overall solder break strength of the subgrid 14.The subgrid overlap segment 142 within the above-mentioned length range can also avoid a larger light-blocking area of ​​the subgrid 14 caused by excessive length, meaning that the light-blocking area of ​​this subgrid overlap segment 142 is small and the paste consumption during printing is also low.

[0073] In some embodiments, such as in Fig. As shown in Figure 11, several main grid overlap lines 161 are arranged on the main grid 16, each main grid overlap line 161 being located at the intersection between the main grid 16 and the respective subgrid 14, and each main grid overlap line 161 being at least partially stacked with the respective subgrid overlap segment 142.

[0074] In particular, the main lattice 16 and the main lattice overlap lines 161 are printed together, followed by the printing of the sublattices 14 to form the sublattice overlap segment 142. The sublattice overlap segment 142 is superimposed on the side of the main lattice overlap line 161 facing away from the substrate 11 to form an overlap structure that is taller than the sublattice 14. The outline of the main lattice overlap line 161 is shown in Fig. Figure 11 is represented by dashed lines. Thus, the solar cell 10 of the present application can achieve an overlap structure with a height greater than that of the subgrid 14 without requiring additional printing steps. Alternatively, the present application can first print the subgrid 14 to form the subgrid overlap segment 142, followed by printing the main grating 16 and the main grating overlap line 161. In this case, the main grating overlap line 161 is superimposed on a side of the subgrid overlap segment 142 facing away from the substrate 11.

[0075] Since the subgrid overlap segment 142 is printed together with the rest of the subgrid 14, its height is equal to or only slightly different from the height of the rest of the subgrid 14. This solar cell 10 further forms an overlap structure by superimposing the main grid overlap line 161 onto the subgrid overlap segment 142. The height of this overlap structure can exceed that of the subgrid 14. After the solder tape is applied, the overlap structure, which is higher than the subgrid 14, can prevent the solder tape from coming into contact with the subgrid 14. This further reduces the occurrence of grid breaks in the subgrid 14 during solder tape welding, increases the output current of the subgrid 14, and thus contributes to improving the conversion efficiency of the solar cell 10.

[0076] In the embodiment of the present application, as in Fig. Figure 11 shows the dimension of the main grid overlap line 161 in the second direction Y, the width.

[0077] Optionally, the central part of the main grid overlap line 161 overlaps with the main grid 16 in the first direction X, with the width of the main grid overlap line 161 decreasing from the center to both ends. The width at the widest point of the main grid overlap line 161 is W4, where W4 > W2.

[0078] It is understood that if the width W4 at the widest point of the main grid overlap line 161 satisfies the condition W4 > W2, this means that the main grid overlap line 161 uses a larger volume of paste material during printing compared to the subgrid main body segment 143, thus achieving a greater width. This means that the main grid overlap line 161 contains a higher amount of electrode material (e.g., silver). When soldering the main grid 16 to the solder tape, the main grid overlap line 161, which contains more electrode material, can better withstand the corrosive reaction of the solder tape. This improves the solder fracture strength of the main grid overlap segment 161, thereby reducing the fracture rate of the main grid overlap line 161. Therefore, it improves the current collection capacity of the solar cell 10, which in turn contributes to improving the conversion efficiency of the solar cell 10.

[0079] For example, the central part of the main grid overlap line 161 can have a square configuration with trapezoidal extensions at both ends. This arrangement results in a uniform width in the central part of the main grid overlap line 161, and the widths of the extension sections at both ends decrease. Alternatively, the main grid overlap line 161 can have a rhombic configuration, meaning the overall width of the main grid overlap line 161 decreases. Of course, the reduction in the width of the main grid overlap line 161 can also be achieved through a graduated reduction, in which the main grid overlap line 161 has a graduated shape.

[0080] Optionally, the width W4 at the widest point of the main grid overlap line 161 is 30 µm to 80 µm, encompassing any value within this range, for example, 30 µm, 50 µm, or 80 µm. If the width W4 at the widest point of the main grid overlap line 161 lies within the aforementioned width range, the width at the widest point of the main grid overlap line 161 is sufficiently large. The solder joint strength of the main grid overlap line 161 is directly proportional to its line width, meaning that the solder joint strength is improved in the central part of the main grid overlap line 161.Furthermore, the main grid overlap line 161 can avoid excessive light blocking area and excessive consumption of printing paste caused by excessive line width, meaning that the light blocking area of ​​this main grid overlap line 161 is small and the wet weight of the paste during printing is low.

[0081] Optionally, the width W5 at the narrowest point of the main lattice overlap line 161 is 8 µm to 30 µm and includes any value within this width range, for example, 8 µm, 20 µm, or 30 µm. If the width W5 at the narrowest point of the main lattice overlap line 161 complies with the aforementioned width range, the narrowest point of the main lattice overlap line 161 is sufficiently narrow to result in a smaller light-blocking area and lower paste consumption. Furthermore, the main lattice overlap line 161 can avoid the increased resistivity caused by an excessively small width, meaning that the main lattice overlap line 161 has a lower resistivity.

[0082] Optionally, the length L2 of the main grid overlap line 161 in the first direction X is 0.3 mm to 2 mm and includes any value within this length range, for example, 0.3 mm, 1 mm, or 2 mm. If the length L2 of the main grid overlap line 161 in the first direction X is within the aforementioned length range, the main grid overlap line 161 is of sufficient length. This ensures that even if the solder band shifts, it can still make contact with the wider overlap structure, thereby improving the overall solder break strength of the subgrid 14.The main lattice overlap line 161 within the above-mentioned length range can also avoid a larger light-blocking area caused by excessive length, meaning that the light-blocking area of ​​the overlap structure composed of the main lattice overlap line 161 and the sublattice overlap segment 142 is small and the paste consumption during printing is also low.

[0083] It should be noted that the dimensions of the main grid overlap line 161 in Fig. 11 are somewhat smaller than those of the subgrid overlap segment 142 to facilitate the illustration of the main lattice overlap line 161 and the subgrid overlap segment 142. It is understood that the dimensions of the main lattice overlap line 161 may also be completely identical to those of the subgrid overlap segment 142, or alternatively, one or more dimensions of the main lattice overlap line 161 may be larger than those of the subgrid overlap segment 142, without any limitation being imposed by the embodiments of the present application.

[0084] In the embodiment of the present application, the substrate 11, with reference to Fig. Let 12 have a dimension D1 in the first direction X, and the length of a single sublattice 14 be L3. It is understood that if L3 / D1 is less than 3%, the length of a single sublattice 14 is relatively short, and the number of sublattices 14 within a series of sublattices 14 is relatively high. Accordingly, the number of intersecting segments 141 within this series of sublattices 14 and the number of required connecting grid lines 15 also increase. However, a larger number of connecting grid lines 15 increases the probability of misalignment between the sublattices 14 and the connecting grid lines 15 during the printing process of this series of sublattices 14. Since the connecting grid lines 15 do not collect current, an excessive number of connecting grid lines 15 also reduces the current-collecting capacity of the series of sublattices 14.If L3 / D1 exceeds 20%, the length of each individual subgrid 14 is greater, and consequently, the subgrid printing openings 21 on the subgrid screen printing sheet 20 are also longer, thereby reducing the structural strength and service life of the subgrid screen printing sheet 20. Optionally, L3 / D1 is in the range of 3%–20%, for example, 3%, 5%, 10%, 15%, or 20%. If the length L3 of an individual subgrid 14 falls within the aforementioned L3 / D1 range, the number of intermediate sections 141 and the required number of connecting grid lines 15 within a series of subgrids 14 are reduced. This improves the current collection capacity of this series of subgrids 14 and reduces misalignments when printing subgrids 14 and connecting grid lines 15. Conversely, by avoiding excessive length, the subgrids 14 give the subgrid screen printing sheet 20 higher structural strength.

[0085] It should be noted that in the embodiments of the present application, it is sufficient if at least one subgrid 14 satisfies the aforementioned L3 / D1 ratio range. Of course, several subgrids 14 can all satisfy this L3 / D1 ratio range without any restriction being imposed by the embodiments of the present application.

[0086] Optionally, the length L3 of a single sublattice 14 in the first direction X is 5.4 mm to 42 mm, encompassing any value within this length range, for example, 5.4 mm, 10 mm, 20 mm, 30 mm, or 42 mm. When the length of a single sublattice 14 is within the aforementioned length range, the number of sublattices 14 within a series of sublattices 14 is relatively small. This consequently reduces the number of intersecting sections 141 and the required connecting grid lines 15. As analyzed above, this approach can reduce misalignment between sublattices 14 and connecting grid lines 15, thereby improving the current-collecting capacity of this series of sublattices 14.Since the length of the subgrid pressure openings 21 corresponds to the length of the subgrid 14, the length of the subgrid pressure openings 21 is significantly smaller compared to the dimensions of the subgrid screen printing sheet 20 when a single subgrid 14 falls within the aforementioned length range, thus giving the subgrid screen printing sheet 20 a higher structural strength.

[0087] Optionally, the substrate 11 has a dimension D1 in the first direction X of 156 mm to 211 mm, for example 156 mm, 182 mm or 211 mm.

[0088] In the embodiments of the present application, as in Fig. Figure 12 shows the width of a single intermediate section 141 in the first direction X W7. It should be noted that if W7 / D1 is less than 0.1%, the distance between two subgrid printing openings 21 on the subgrid screen sheet 20 is smaller. Excessive proximity between these two weak points leads to a reduction in the structural strength of the subgrid screen sheet 20. If W7 / D1 exceeds 1.1%, the intermediate section 141 becomes wider, requiring a longer connecting grid line 15 to link the subgrids 14 at both ends of the intermediate section 141. This increases the proportion of connecting grid lines 15 within a single row of subgrids 14, thereby deteriorating the current-collecting effect of that row of subgrids 14. Optionally, W7 / D1 is in the range of 0.1%–1.1%, for example, 0.1%, 0.6%, or 1.1%.If W7 / D1 lies within the aforementioned ratio range, the two subgrid pressure openings 21 on the subgrid screen sheet 20 are further apart. This allows for improved structural strength and service life of the subgrid screen sheet 20 and simultaneously prevents excessive length of the connecting grid line 15 within the intermediate section 141, thus improving the current collection capacity of a series of subgrids 14.

[0089] Optionally, the width W7 of a single intermediate section 141 in the first direction X is 0.2 mm to 2 mm and includes any value within this width range, for example, 0.2 mm, 1 mm, or 2 mm. If the width W7 of the intermediate section 141 in the first direction X is within the aforementioned width range, the two subgrid printing openings 21 on the subgrid screen sheet 20 are further apart. This allows for improved structural strength and service life of the subgrid screen sheet 20 and simultaneously prevents excessive length of the connecting grid line 15, thus improving the current collection capacity of a series of subgrids 14.

[0090] Optional, as in Fig. Figure 13 shows the total length of all sublattices 14 in at least one row of sublattices 14 L4 and the distance between the two ends of this row of sublattices 14 in the first direction X D2, where L4 / D2 is 95%–99%, for example 95%, 97%, or 99%. It should be noted that the total length L4 of all sublattices 14 is equal to the sum of the lengths L3 of all sublattices 14 in this row of sublattices 14.

[0091] If L4 / D2 falls within the aforementioned ratio range, this means that the length ratio of the subgrids 14 within a series of subgrids 14 is sufficiently high, thus improving the current collection efficiency. It also means that the intermediate sections 141 between the individual subgrids 14 are sufficiently wide and that the subgrid pressure openings 21 on the subgrid screen sheet 20 are further apart, which in turn improves the structural strength and service life of the subgrid screen sheet 20.

[0092] The connecting grid lines 15 are described in detail below.

[0093] In some embodiments, as in Fig. Figure 14 shows the pattern of the connecting grid line 15 as either a solid pattern or a hollow pattern. Specifically, the term "solid pattern" refers to a pattern that is completely filled inside and has no hollow sections. The term "high pattern" refers to a pattern that is hollow inside and includes only boundary lines.

[0094] As in Fig. As shown in Figure 14a, in the case of a connecting grid line 15 with a hollow pattern, the filling with paste is omitted due to the inner cavity; therefore, the light-blocking area of ​​the connecting grid line 15 is smaller and the wet weight of the paste during printing is also lower.

[0095] As in Fig. As shown, the interior of the connecting grid line 15 can be filled with paste if the pattern of the connecting grid line 15 is a solid pattern. This achieves better paste filling, thereby reducing ghosting in the connecting grid line 15 and improving the print quality of the connecting grid line 15. The overlap effect between the subgrid 14 and the connecting grid line 15 of the solid pattern is also present and leads to a higher overlap success rate.

[0096] In the present application, the term “ghost images” refers to the phenomenon in which grid line prints appear blurred, unclear or incomplete in processes such as screen printing.

[0097] Optionally, the shape of the connecting grid line 15 can be symmetrical or asymmetrical.

[0098] More precisely, the term "symmetrical shape" refers to a shape in which folding the connecting grid line 15 along a straight line results in a perfect overlap of the sections on both sides of the fold. Symmetrical connecting grid lines 15 improve the aesthetic appearance of the solar cell 10.

[0099] As in Fig. 14a and Fig. As shown in Figure 14b, the connecting grid line 15, if it assumes a symmetrical shape, takes the form of a rectangle. Of course, the connecting grid line 15 can also be square, circular, I-shaped, triangular, or linear.

[0100] More precisely, the term "asymmetric shape" refers to a shape that lacks symmetry under certain transformation relations, meaning that it cannot be brought to perfect overlap through operations such as translation, rotation, or reflection. An asymmetrically shaped connecting grid line 15 can be used to connect two subgrids 14 that are asymmetrically or irregularly distributed.

[0101] As in Fig. As shown in Figure 14c, the connecting grid line 15, when it assumes an asymmetrical shape, takes on a wavy configuration. Of course, the connecting grid line 15 can also take the form of an inequal-sided triangle or a right-angled shape.

[0102] Optionally, the dimension D3 of the connecting grid line 15 in the second direction Y is 0.02 µm to 0.3 µm and includes any value within this dimensional range, for example, 0.02 µm, 0.1 µm, or 0.3 µm. If the dimension D3 of the connecting grid line 15 in the second direction Y fulfills the aforementioned dimensional range, the connecting grid line 15 has a smaller light-blocking area and a lower resistivity, while the subgrid 14 still allows alignment with the connecting grid line 15 if the subgrid is printed with a certain offset.

[0103] Optionally, the dimension D4 of the connecting grid line 15 in the first direction X is 0.2 mm to 2 mm and includes any value within this dimensional range, for example, 0.2 mm, 1 mm, or 2 mm. If the dimension D4 of the connecting grid line 15 in the first direction X falls within the aforementioned dimensional range, it reduces the wet weight of the paste during printing of the connecting grid line 15 and simultaneously effectively connects the two subgrids 14 on both sides of the intermediate section. This ensures alignment with the connecting grid line 15, even if the subgrid 14 is printed with some offset.

[0104] In a second aspect, an embodiment of the present application discloses a photovoltaic module as shown in Fig.As shown in Figure 15, it comprises several solar cells connected in series and / or parallel, with at least one solar cell 10 being the solar cell 10 in the first aspect. More precisely, the solar cells 10 are connected in series and / or parallel via electrical connecting elements 30, which can be, for example, solder strips or conductive wires.

[0105] Finally, it should be noted that the foregoing embodiments serve only to illustrate the technical solution of the present application, rather than to limit it. Although the present application is further explained in connection with the foregoing embodiments, the person skilled in the art should understand that they may modify the technical solutions presented in the foregoing embodiments or replace the technical features partially or entirely with equivalent ones. With such modifications or replacements, the corresponding technical solutions should still be considered to be covered by the concept and scope of the technical solutions of the respective embodiments of the present application.

Claims

[1] Solar cell, characterized by that it includes the following: a substrate; a doped layer that is arranged on the surface of the substrate; a first functional membrane that is arranged on a surface of the doped layer facing away from the substrate; several sublattices, each arranged on the first functional membrane and penetrating the first functional membrane to establish an ohmic contact with the doped layer; wherein the longitudinal direction of the sublattice is a first direction, and wherein the several sublattices are arranged in a row at intervals along the first direction; and wherein within the same row of sublattices there is an intermediate section between each pair of adjacent sublattices; several connecting grid lines arranged on one side of the first functional membrane facing away from the doped layer and embedded in a portion of the thickness of the first functional membrane; and wherein a connecting grid line is arranged in each intermediate section, and wherein, in the first direction, the connecting grid line is connected between two sublattices on both sides of the intermediate section; and a main grid located at the first functional membrane and extending along a second direction, the second direction intersecting with the first direction, and the main grid intersecting with the connecting grid line or sublattice to electrically connect a series of sublattices. [2] Solar cell according to claim 1, characterized by, that the sublattices comprise several rows, wherein the several rows of sublattices are spaced apart in the second direction, and wherein each main lattice overlaps with the several rows of sublattices; wherein among the several sublattices that overlap with the same main lattice, two adjacent sublattices are partially offset in the first direction. [3] Solar cell according to claim 2, characterized by, that several principal grids are provided, wherein the several principal grids are arranged at intervals in the first direction; wherein the orthogonal projection of a single subgrid in a row of two adjacent rows of subgrids in the second direction overlaps with the orthogonal projections of several subgrids in the other row in the second direction and forms an overlapping region with them, and wherein the subgrids lying in the overlapping region intersect with the principal grids. [4] Solar cell according to any one of claims 1 to 3, characterized by , that when the main lattice overlaps with the sublattice, the sublattice has several sublattice overlap segments, with each sublattice overlap segment being located at the intersection point between the sublattice and the respective main lattice. [5] Solar cell according to claim 4, characterized by, that several main lattice overlap lines are arranged on the main lattice, with each main lattice overlap line being located at the intersection between the main lattice and the respective sublattice, and with each main lattice overlap line being at least partially stacked with the respective sublattice overlap segment. [6] Solar cell according to claim 5, characterized by , that the dimension of the sublattice overlap segment in the second direction is the width; wherein in the first direction the central part of the sublattice overlap segment overlaps with the main lattice, and wherein the width of the sublattice overlap segment decreases from the center to both ends; and wherein the width at the widest point of the sublattice overlap segment is W1; and wherein in each sublattice the width of the section outside the sublattice overlap segment is W2, and wherein W1 > W2. [7] Solar cell according to claim 6, characterized by , that the dimension of the main grid overlap segment in the second direction is the width; wherein in the first direction the middle part of the main grid overlap line overlaps with the main grid, and wherein the width of the main grid overlap line decreases from the middle to both ends; and wherein the width at the widest point of the main grid overlap line is W4, and wherein W4 > W2. [8] Solar cell according to any one of claims 5 to 7, characterized by , that the width W1 at the widest point of the subgrid overlap segment is 30 µm to 80 µm. [9] Solar cell according to any one of claims 5 to 8, characterized by , that the width W2 of the section of each sublattice except the sublattice overlap segment is 8 µm to 30 µm. [10] Solar cell according to any one of claims 5 to 9, characterized by, that the width W3 at the narrowest point of the subgrid overlap segment is 8 µm to 30 µm. [11] Solar cell according to any one of claims 5 to 10, characterized by , that the width W4 at the widest point of the main lattice overlap line is 30 µm to 80 µm. [12] Solar cell according to any one of claims 5 to 11, characterized by , that the width W5 at the narrowest point of the main lattice overlap line is 8 µm to 30 µm. [13] Solar cell according to any one of claims 5 to 12, characterized by , that the length L1 of the subgrid overlap segment in the first direction is 0.3 mm to 2 mm. [14] Solar cell according to any one of claims 5 to 13, characterized by , that the length L2 of the main grid overlap line in the first direction is 0.3 mm to 2 mm. [15] Solar cell according to any one of claims 1 to 14, characterized bythat the pattern of the connecting grid line is either a solid pattern or a hollow pattern. [16] Solar cell according to claim 15, characterized by that the shape of the connecting grid line is symmetrical or asymmetrical. [17] Solar cell according to claim 16, characterized by , that if the shape of the connecting grid line is symmetrical, the connecting grid line is rectangular, square, circular, I-shaped, triangular or straight. [18] Solar cell according to claim 16, characterized by , that if the shape of the connecting grid line is asymmetrical, the connecting grid line has the shape of a wavy line, an asymmetrical triangle, or a right-angled shape. [19] Solar cell according to any one of claims 1 to 18, characterized by , that the substrate has a dimension D1 in the first direction, where the length of a single sublattice is L3 and L3 / D1=3%-20%. [20] Solar cell according to any one of claims 1 to 19, characterized by , that in at least one series of sublattices the total length of all sublattices is L4 and the distance between the two ends of this series of sublattices in the first direction is D2, where L4 / D2=95%-99%. [21] Solar cell according to any one of claims 1 to 20, characterized by , that the substrate has a dimension D1 in the first direction, wherein the width of a single intermediate section in the first direction is W7, and wherein W7 / D1=0.1%-1.1%. [22] Solar cell according to any one of claims 1 to 21, characterized by , that the length L3 of a single subgrid in the first direction is 5.4 mm to 42 mm. [23] Solar cell according to any one of claims 1 to 22, characterized by , that the width W7 of a single intermediate section in the first direction is 0.2 mm to 2 mm. [24] Solar cell according to any one of claims 1 to 23, characterized by, that the dimension D3 of the connecting grid line in the second direction is 0.02 µm to 0.3 µm. [25] Solar cell according to any one of claims 1 to 24, characterized by , that the dimension D4 of the connecting grid line in the first direction is 0.2 mm to 2 mm. [26] Solar cell according to any one of claims 1 to 25, characterized by that the first direction is perpendicular to the second direction. [27] Photovoltaic module, characterized by , that it comprises several solar cells connected in series and / or parallel, wherein at least one solar cell is the solar cell according to one of claims 1 to 26.

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