Solar cell, fabrication method therefor and photovoltaic module

Abstract

Disclosed in the present application are a solar cell, a fabrication method therefor and a photovoltaic module. The solar cell comprises: a cell substrate, at least one surface of the cell substrate being provided with a plurality of first gate lines alternately arranged in a first direction, and the first gate lines comprising a plurality of first gate line bodies and a plurality of first connection members; and a plurality of first gate line bodies spaced apart in a second direction, the second direction being perpendicular to the first direction, a gap being present between every two adjacent first gate line bodies, and a first connection member being arranged at the gap between every two adjacent first gate line bodies, wherein the distance between every two adjacent first gate lines is D, and the length of each gap in the second direction is S, which satisfies: 0<S≤2D. Therefore, the present application can take into account the current collection range of gate lines by means of ensuring that the current generated by the cell in regions corresponding to the gaps can be effectively collected by the first gate line bodies, and can further ensure the strength of welding between the first connection members and welding strips.

Description

Solar cell, preparation method thereof and photovoltaic module

[0001] The present application claims priority to the Chinese patent application No. 202410824147.6, filed on June 24, 2024, and entitled "Solar cell, preparation method thereof and photovoltaic module", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application belongs to the field of photovoltaic technology, and particularly relates to a solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0003] As a core component of a solar power station, a solar cell can convert solar energy into electrical energy by using a photoelectric effect. With the continuous development of solar cell technology, there is widespread concern about reducing the cost and improving the efficiency of solar cells.

[0004] In related technologies, the electrode structure of a solar cell mainly comprises a plurality of main grid lines and a plurality of fine grid lines. The main grid lines and the fine grid lines are connected perpendicularly and cross each other. The fine grid lines are used to collect the current generated by the solar cell, and the main grid lines are used to collect the current on the fine grid lines. The main grid lines are welded with a soldering pad and a soldering ribbon, and the current collected by the main grid lines is led out to the outside of the solar cell through the soldering ribbon.

[0005] However, in the related art, the positive and negative main grid lines of the electrode structure block light. Since the positive and negative electrodes are both arranged on the back surface of the solar cell, all the fine grid lines with different polarities located on both sides of the main grid lines need to be broken, the migration distance of the charge carriers at the electrode vacancy position is increased, the loss is greater, and the performance of the solar cell is affected. SUMMARY

[0006] The present application aims to provide a solar cell, a preparation method thereof and a photovoltaic module, which can solve the above technical problems.

[0007] To solve the above technical problems, the present application is implemented as follows:

[0008] In a first aspect, the present application provides a solar cell, comprising: a cell substrate, at least one surface of the cell substrate is provided with a plurality of first grid lines arranged alternately along a first direction, the first grid lines comprise a plurality of first grid line bodies and a plurality of first connecting pieces; a plurality of first grid line bodies are arranged at intervals along a second direction, the second direction is perpendicular to the first direction; a gap is provided between adjacent two first grid line bodies, and the first connecting piece is arranged at the gap between the adjacent two first grid line bodies; wherein the distance between adjacent two first grid lines is D, the length of the gap along the second direction is S, and 0<S≤2D is satisfied.

[0009] Optionally, a length of the first connecting member along the second direction is L, and D≤S≤L-400μm is satisfied.

[0010] Optionally, a distance D between two adjacent first gate lines satisfies 210μm≤D≤1000μm.

[0011] Optionally, the first connecting member at least partially overlaps the first gate line body, and a length d of the overlapping part of the first connecting member and the first gate line body along the second direction satisfies 0

[0012] Optionally, a width of the first connecting member along the first direction is W, and a length of the first connecting member along the second direction is L, and 1.4≤L / W≤5 is satisfied.

[0013] Optionally, a width of the first connecting member along the first direction is W, and 210μm≤W≤1200μm is satisfied.

[0014] Optionally, a second connecting member is further included, and the second connecting member is connected with at least one first gate line, wherein a projection area of the second connecting member along a third direction is greater than a projection area of the first connecting member along the third direction, and the third direction is perpendicular to the first direction and the second direction respectively.

[0015] Optionally, a projection area of the first connecting member along the third direction is S1, and a projection area of the second connecting member along the third direction is S2, and 1.1≤S2 / S1≤1.5 is satisfied.

[0016] Optionally, a third connecting member is further included, and the third connecting member extends along the first direction and is connected with at least one first gate line; and the third connecting member is closer to an edge of the battery substrate than the second connecting member.

[0017] Optionally, along the first direction, a width of the connecting member is greater than a width of the first gate line body.

[0018] Optionally, the first gate lines on a same surface of the battery substrate have two kinds of conductive types with opposite conductive types, and the first connecting members in the first gate lines of a same conductive type are arranged correspondingly along the first direction, and the first connecting members in the first gate lines of different conductive types are staggered along the first direction.

[0019] Optionally, a maximum height H of the first connecting member along a third direction satisfies 3μm≤H≤5μm, and the third direction is perpendicular to the first direction and the second direction respectively.

[0020] Optionally, a side surface of the first connecting member away from the battery substrate is curved, and the curved surface is recessed from the peripheral edge towards the center.

[0021] Optionally, the battery substrate has two side edge regions arranged opposite in the second direction, and at least one of the side edge regions is provided with a connecting line electrically connecting end portions of the first grid lines of the same polarity.

[0022] Optionally, the first connecting member covers the gap; or the first grid line body at least partially overlaps the first connecting member.

[0023] In a second aspect, the present application provides a photovoltaic module comprising the solar cell described above.

[0024] In a third aspect, the present application provides a method for manufacturing the solar cell described above, the method comprising:

[0025] printing a plurality of first grid lines spaced apart on at least one side of the battery substrate, the first grid lines comprising a plurality of first grid line bodies spaced apart, and a gap between adjacent two first grid line bodies;

[0026] printing a plurality of first connecting members spaced apart, so that the first connecting members cover the gaps.

[0027] In the present application, by arranging a plurality of first grid lines alternately arranged in the first direction on at least one side of the battery substrate, and arranging the first grid lines to comprise a plurality of first grid line bodies spaced apart, a first connecting member is arranged at the gap between adjacent two first grid line bodies. The first connecting member can be connected with the solder strip, and the current collected by the first grid line body can be converged on the solder strip by the first connecting member and led out by the solder strip. And the inventors have verified through multiple tests and calculation analysis that by setting the length of the gap in the second direction to be less than or equal to 2 times the interval between adjacent two first grid lines, the range of current collection by the grid line can be considered, and it is ensured that the current generated by the battery in the gap corresponding area can be effectively collected by the first grid line body. In addition, the amount of paste used to prepare the first grid line body can also be saved.

[0028] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings.

[0030] FIG. 1 is a schematic view of a solar cell according to an embodiment of the present application;

[0031] FIG. 2 is a partial schematic view of a solar cell according to an embodiment of the present application;

[0032] FIG. 3 is a cross-sectional view of a solar cell at a first grid line according to an embodiment of the present application;

[0033] FIG. 4 is a flowchart of a method of manufacturing a solar cell according to an embodiment of the present application.

[0034] Reference numerals: 11: first grid line; 101: first grid line body; 102: first connecting member; 103: gap; 14: second connecting member; 15: third connecting member; 16: connecting line; 20: cell base; X: first direction; Y: second direction; Z: third direction. DETAILED DESCRIPTION

[0035] Embodiments of the present application will be described in detail below with reference to the drawings, in which like reference numerals refer to like elements throughout. The embodiments described below are examples of the present application, and are merely intended to explain the present application, and should not be construed in a limiting sense. All other embodiments obtained by those skilled in the art based on the embodiments of the present application, without creative effort, are within the scope of the present application.

[0036] The terms "first", "second" in the specification and claims of the present application can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in an "or" relationship.

[0037] In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] The solar cell and the preparation method thereof, the solar cell and the photovoltaic module provided by the embodiments of the present application will be described in detail below in combination with the drawings, specific embodiments and application scenarios.

[0040] As shown in FIG. 1 and FIG. 2, according to some embodiments of the present application, the solar cell comprises a cell substrate 20, a plurality of first grid lines 11 arranged alternately along a first direction X are arranged on at least one side of the cell substrate 20, and the first grid line 11 comprises a plurality of first grid line bodies 101 arranged at intervals, and a first connecting piece 102 is arranged at the gap between the adjacent two first grid line bodies 101. The first connecting piece 102 is in direct contact with the cell substrate 20 at the gap 103, which can improve the bonding strength of the first connecting piece 102 and the cell substrate 20, and the first connecting piece 102 is used to connect with the solder strip, so as to converge the current collected by the first grid line body 101 to the solder strip through the first connecting piece 102 and lead out by the solder strip.

[0041] According to some embodiments of the present application, the solar cell comprises a cell substrate 20, a plurality of first grid lines 11 arranged alternately along a first direction X are arranged on at least one side of the cell substrate 20, and the first grid line 11 comprises a plurality of first grid line bodies 101 arranged at intervals and a plurality of first connecting pieces 102; the plurality of first grid line bodies 101 are arranged at intervals along a second direction Y perpendicular to the first direction X; a gap 103 is arranged between the adjacent two first grid line bodies 101, the first connecting piece 102 covers the gap 103, and the two ends of the first connecting piece 102 are respectively overlapped with the first grid line bodies 101.

[0042] In some embodiments, by arranging the first grid line 11 to include a plurality of spaced first grid line bodies 101 and a plurality of first connecting members 102, and arranging the first connecting member 102 at the gap 103 between two adjacent first grid line bodies 101, the first connecting member 102 is in direct contact with the battery substrate 20 at the gap 103, which can improve the bonding strength between the first connecting member 102 and the battery substrate 20. Meanwhile, the first connecting member 102 is used to connect with the solder ribbon, so that the current collected by the first grid line body 101 is converged to the solder ribbon through the first connecting member 102 and led out by the solder ribbon. In addition, by covering the first connecting member 102 at the gap 103, not only the paste of the first grid line body 101 can be saved, but also the height of the first grid line 11 at the gap 103 can be reduced, which helps to improve the overall flatness of the first grid line 11.

[0043] In some embodiments, the first grid line body 101 uses a burn-through type paste, and the first connecting member 102 uses a non-burn-through type paste.

[0044] In some embodiments, the first grid line body 101 overlaps the first connecting member 102, and the first grid line body 101 overlaps the first connecting member 102. By using this overlapping manner, the influence of the first grid line body 101 on the surface contact performance of the first connecting member 102 and the battery substrate 20 can be reduced, and the contact between the first connecting member 102 and the battery substrate 20 is better.

[0045] In some embodiments, the distance between two adjacent first grid lines 11 is D, and the length S of the gap 103 along the second direction Y satisfies: 0 < S ≤ 2D.

[0046] The inventors of the present application have verified through multiple tests and calculation analysis that by setting the length S of the gap 103 along the second direction Y to be less than or equal to twice the distance D between two adjacent first grid lines 11, the range of current collection by the grid line can be considered, and it is ensured that the current generated by the battery in the region corresponding to the gap 103 can be effectively collected by the first grid line body 101, and at the same time, the welding strength of the first connecting member 102 and the solder ribbon can be ensured. In addition, the amount of paste used to prepare the first grid line body 101 can be saved, and the actual processing is also facilitated.

[0047] It can be understood that the solar cell in the embodiments of the present application can include a back contact cell, but is not limited to a back contact cell. In actual use, a screen printing process can be used to print paste on the surface of the battery substrate 20 to form a plurality of first grid lines 11.

[0048] As shown in FIG. 1 and FIG. 2, a plurality of first grid lines 11 are arranged on the surface of the cell substrate 20 in the solar cell, each of the first grid lines 11 includes a plurality of first grid line bodies 101 arranged at intervals along a second direction Y, and a first connecting piece 102 is arranged at a gap 103 between two adjacent first grid line bodies 101, and the two ends of the first connecting piece 102 are respectively overlapped with the first grid line bodies 101.

[0049] Wherein, the first grid line body 101 can be ohmically connected with the cell substrate 20, and the current generated by the photoelectric conversion of the cell substrate 20 can be collected by the first grid line body 101, and the first connecting piece 102 can be connected with the solder strip, and the current collected by the first grid line body 101 can be converged to the solder strip through the first connecting piece 102.

[0050] In the present application, the size of the interval D between the two adjacent first grid lines 11 is related to the range that can be covered when each first grid line 11 collects current, and therefore, the size of the gap 103 between the two adjacent first grid line bodies 101 is further set based on the interval D, so that the current at the gap 103 can be effectively collected by the first grid line body 101.

[0051] Further, the inventors have verified through multiple tests and continuous analysis and summary that when the length S of the gap 103 between the two adjacent first grid line bodies 101 along the second direction Y is less than or equal to 2 times the interval D, the carriers at the gap 103 between the two first grid line bodies 101 can be effectively collected by the first grid line bodies 101 on both sides, thereby ensuring the current collection range of the grid line; at the same time, by connecting the relatively wide first connecting piece 102 with the solder strip, the welding strength of the first grid line 11 and the solder strip can be improved, which can meet the processing requirements and also consider the performance of the solar cell.

[0052] Wherein, the size of the interval D between the two adjacent first grid lines 11 can be set according to the layout structure of the auxiliary grid in the related art, which is not limited in the present application.

[0053] It should be noted that when the widths of the first grid line body 101 and the first connecting piece 102 in the first grid line 11 are not equal, the interval D refers to the interval between the two adjacent first grid line bodies 101 along the first direction X. For example, the S can be set as 0.3D, 0.5D, 0.8D, 1.0D, 1.2D, 1.5D, etc. It can be flexibly set according to the actual situation, which is not limited in the present application.

[0054] Further, 0<S≤D can be set, which can further improve the collection ability of the first grid line body 101 to the carriers at the gap 103 and improve the efficiency of the solar cell.

[0055] Optionally, as shown in FIG. 1, the width of the first connecting piece 102 is greater than the width of the first grid line body 101 along the first direction X.

[0056] In some embodiments, the width of the first connecting piece 102 is set to be greater than the width of the first grid line body 101 to facilitate the connection of the first connecting piece 102 with the solder strip, so that the first connecting piece 102 can serve both the collection of current from the first grid line body 101 and the connection with the solder strip.

[0057] Optionally, as shown in FIG. 1, the first grid lines 11 on the same surface of the battery substrate 20 have two types of conductive types with opposite conductive types, and the first connecting pieces 102 in the first grid lines 11 of the same conductive type are arranged correspondingly along the first direction X, while the first connecting pieces 102 in the first grid lines 11 of different conductive types are staggered along the first direction X.

[0058] In some embodiments, by setting the conductive types of the adjacent two first grid lines 11 to be opposite, and the first connecting pieces 102 in the first grid lines 11 of the same conductive type to be correspondingly arranged along the first direction X, while the first connecting pieces 102 in the first grid lines 11 of different conductive types to be staggered along the first direction X, the connection of the first grid lines 11 of the same conductive type with the solder strip is facilitated. With the electrode structure in the present application, the layout requirement of arranging the grid lines with opposite conductive types on the same surface of the battery can be met.

[0059] In the plurality of first grid lines 11, the conductive types of the adjacent two first grid lines 11 are opposite, that is, one is set as a positive grid line, and the other is set as a negative grid line, so that the plurality of positive grid lines and the plurality of negative grid lines are arranged alternately to form the positive and negative electrode structure of the solar cell.

[0060] In some embodiments, the plurality of first grid lines 11 on the surface of the battery substrate 20 can be arranged alternately according to the positive grid lines and the negative grid lines; or, the adjacent two positive grid lines can be arranged with two or more negative grid lines therebetween; or, the adjacent two negative grid lines can be arranged with two or more positive grid lines therebetween. Of course, other arrangement manners can also be adopted, which can be set flexibly according to actual conditions, and the present application is not limited in this regard.

[0061] In the plurality of first grid lines 11, the conductive types of the adjacent two first grid lines 11 are opposite, that is, one is set as a positive grid line, and the other is set as a negative grid line, so that the plurality of positive grid lines and the plurality of negative grid lines are arranged alternately to form the positive and negative electrode structure of the solar cell.

[0062] And, the first connecting pieces 102 in the first grid lines 11 of the same conductive type correspond to each other in the first direction X, and the first connecting pieces 102 in the first grid lines 11 of different conductive types are staggered with each other in the first direction X. In this way, it is convenient to connect multiple first grid lines 11 of the same conductive type in series by using the same solder strip. In addition, interference between the solder strips connected to the first grid lines 11 of different conductive types can be avoided.

[0063] It should be noted that when the solder strip is welded with the first connecting piece 102 on the first grid line 11 of the same conductive type, an insulating adhesive can be arranged between the solder strip and the first grid line 11 of another conductive type to insulate and avoid short circuit between the first grid lines 11 of two different conductive types.

[0064] In specific applications, the first connecting piece 102 on each first grid line 11 can be one or multiple, as long as the number and position of the first connecting pieces 102 on the first grid lines 11 of the same conductive type correspond to each other.

[0065] It should be noted that the first connecting pieces 102 correspond to each other in the first direction X means that the orthographic projections of the corresponding two or more first connecting pieces 102 in the first direction X at least partially coincide, and the first connecting pieces 102 are staggered with each other in the first direction X means that the orthographic projections of the corresponding two or more first connecting pieces 102 in the first direction X do not coincide.

[0066] It can be understood that in the back contact battery in the related art, the positive and negative electrodes are both arranged on the back of the battery, and the positive and negative electrodes both include main grids and auxiliary grids, and the main grids and the auxiliary grids of the positive and negative electrodes are distributed in an interdigital structure. All the auxiliary grids on both sides of each main grid need to be broken, which increases the distance of the carrier migration to the auxiliary grid at the vacancy position of the auxiliary grid, and the loss is greater, which affects the battery performance.

[0067] In the embodiment of the present application, a plurality of first grid lines 11 are arranged alternately, and the conductive types of the adjacent two first grid lines 11 are opposite, one of which can be used as a positive grid line, and the other as a negative grid line, so as to collect the current in the corresponding area of the battery by the positive grid line and the negative grid line. Further, the first connecting piece 102 is arranged in each first grid line 11, and the first connecting piece 102 can be connected with the solder strip. No matter the current collected by the positive grid line or the negative grid line, it is all converged to the solder strip through the corresponding first connecting piece 102, so that the main grid in the related art can be removed.

[0068] In some embodiments, the side surface of the first connecting piece 102 away from the battery substrate 20 is curved, and the curved surface is recessed from the periphery edge to the center.

[0069] In some embodiments, the length of the overlap portion of the first connecting piece 102 and the first grid line body 101 along the second direction Y is d, the length of the first connecting piece 102 along the second direction Y is L, and L=S+2d is satisfied. That is, the length L of the first connecting piece 102 can be determined according to the length S of the gap 103 and the overlap size required to meet the processing requirements.

[0070] Optionally, as shown in FIG. 2, the distance between the two adjacent first grid lines 11 is D, the length of the gap 103 along the second direction Y is S, the length of the first connecting piece 102 along the second direction Y is L, and D≤S≤L-400μm is satisfied.

[0071] It can be understood that the smaller the length S of the gap 103, the stronger the current collection capability of the first grid line body 101 at the gap 103, but it will cause the first connecting piece 102 formed to be uneven and waste the raw materials for preparing the first grid line body 101. Therefore, the minimum value of the length S of the gap 103 is set to be equal to the distance D, so as to ensure the current collection capability of the first grid line body 101 at the gap 103, and also to ensure that the first connecting piece 102 at the gap 103 has sufficient contact area with the battery substrate 20, which helps to improve the welding strength, and also reduces the production cost.

[0072] At the same time, when the first connecting piece 102 is processed at the gap 103, the processing error of the processing equipment needs to be considered, that is, the first connecting piece 102 and the overlap portion of the first grid line body 101 need to be reserved with sufficient overlap size, so S≤L-400μm is set, so that the first connecting piece 102 and the overlap portion of the first grid line body 101 have sufficient processing allowance, which is convenient for actual production and processing.

[0073] Optionally, as shown in FIG. 2, the distance D between the two adjacent first grid lines 11 satisfies 210μm≤D≤1000μm. For example, the distance D can be set to be: 210μm, 250μm, 300μm, 400μm, 410μm, 500μm, 800μm, 1000μm, or any value or range between any two values.

[0074] In some embodiments, the distance D between the two adjacent first grid lines 11 is set in a range, so as to take into account the overall design requirements of the electrode structure and the current collection capability of each grid line to the surrounding carriers.

[0075] It can be understood that if the spacing D between two adjacent first grid lines 11 is too small, it is not convenient for the processing of the first grid line 11, and the local short circuit problem of the adjacent first grid line 11 is prone to occur, and if the spacing D is too large, the current in the partial area between the two first grid lines 11 cannot be effectively collected, which will affect the efficiency of the solar cell. Therefore, in some embodiments, by setting a reasonable value range of the spacing D between two adjacent first grid lines 11, the design and processing requirements of the electrode are met, and the collection ability of each first grid line 11 to the surrounding carriers is also considered.

[0076] Optionally, as shown in FIG. 2, the first connecting piece 102 at least partially overlaps the first grid line body 101, and the length d of the overlapping part of the first connecting piece 102 and the first grid line body 101 along the second direction Y satisfies: 0 < d ≤ 400 μm. For example, the length d can be set to: 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, etc. Any numerical value or range between any two numerical values.

[0077] In some embodiments, by setting a reasonable value range of the length d of the overlapping part of the first connecting piece 102 and the first grid line body 101, it is ensured that the first connecting piece 102 and the first grid line body 101 can be effectively connected, while the flatness of the formed first connecting piece 102 is also considered, and the amount of raw materials of the first grid line body 101 is saved.

[0078] It can be understood that if d is greater than 400 μm, that is, the overlapping part between the first connecting piece 102 and the first grid line body 101 is more, although the connection strength of the first connecting piece 102 and the first grid line body 101 can be improved, when the overlapping part is more, the raw material of the first grid line body 101 is wasted, and at the same time, the formed first connecting piece 102 has more uneven parts, which affects the flatness of the overall electrode structure.

[0079] Optionally, as shown in FIG. 2, the width of the first connecting piece 102 along the first direction X is W, the length of the first connecting piece 102 along the second direction Y is L, and the second direction Y is parallel to the extension direction of the first grid line 11, and satisfies: 1.4 ≤ L / W ≤ 5. For example, the ratio of L / W can be set to: 1.4, 1.5, 1.7, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, etc. Any numerical value or range between any two numerical values.

[0080] It can be understood that, in actual application, the first connecting piece 102 is used for welding and fixing with the solder ribbon, increasing the width W of the first connecting piece 102 can increase the welding area, thereby enhancing the welding strength between the first connecting piece 102 and the solder ribbon, thereby helping to improve the reliability of the photovoltaic module. Increasing the length L of the first connecting piece 102 can more easily meet the welding precision requirements of the solder ribbon, and the processing precision requirements of the welding equipment are lower, which can reduce the risk of welding deviation.

[0081] Therefore, in the embodiments of the present application, the aspect ratio L / W of the first connecting piece 102 is set within a certain value range, so as to balance the welding performance of the first connecting piece 102 and the solder ribbon, and reduce the requirement for welding precision, facilitating actual processing and use.

[0082] Exemplarily, the length L of the first connecting piece 102 can be set to 1000 μm, and the width W can be set to 210 μm, that is, the ratio of L / W can be set to 50:10.5. At this time, the effective welding area of the first connecting piece 102 can be ensured, the welding strength with the solder ribbon can be increased, and the actual welding operation is facilitated. In addition, the loss of raw materials for preparing the first connecting piece 102 can also be saved.

[0083] Optionally, as shown in FIG. 2, the width of the first connecting piece 102 along the first direction X is W, which satisfies: 210 μm≤W≤1200 μm. For example, the width W of the first connecting piece 102 can be set to: 210 μm, 250 μm, 300 μm, 400 μm, 410 μm, 500 μm, 800 μm, 1000 μm, 1200 μm, or any value or range between any two values.

[0084] In some embodiments, by setting a reasonable value range of the width W of the first connecting piece 102 along the first direction X, it is ensured that the first connecting piece 102 has sufficient area for connecting with the solder ribbon, and at the same time, the width of the first connecting piece 102 is prevented from being too large, which affects the structural layout of the first grid line 11 and causes waste of raw materials.

[0085] Optionally, as shown in FIG. 3, a third direction Z is defined perpendicular to the first direction X and the second direction Y, respectively, and the maximum height H of the first connecting piece 102 along the third direction Z satisfies: 3 μm≤H≤5 μm. For example, the maximum height H can be set to: 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc.

[0086] In some embodiments, by setting a reasonable value range of the maximum height H of the first connecting piece 102 along the third direction Z, the welding operation of the first connecting piece 102 and the solder ribbon is facilitated, and at the same time, the height of the first connecting piece 102 is prevented from being too high, which affects the flatness of the overall electrode structure.

[0087] Optionally, as shown in FIG. 1, the solar cell further comprises a second connecting piece 14 connected with the at least one first busbar 11, wherein the second connecting piece 14 has a larger area along the third direction Z than the first connecting piece 102.

[0088] In some embodiments, by setting the second connecting piece 14 connected with the at least one first busbar 11 and setting the second connecting piece 14 having a larger area along the third direction Z than the first connecting piece 102, the second connecting piece 14 has a larger area for soldering with the solder strip, thereby improving the soldering strength between the second connecting piece 14 and the solder strip.

[0089] Optionally, as shown in FIG. 1, the first connecting piece 102 has a projection area S1 along the third direction Z, and the second connecting piece 14 has a projection area S2 along the third direction Z, and the ratio S2 / S1 satisfies 1.1≤S2 / S1≤1.5. For example, the ratio S2 / S1 can be set as 1.1, 1.2, 1.2, 1.4, 1.5, or any value or range between any two values.

[0090] In some embodiments, by setting the ratio of the projection area S2 of the second connecting piece 14 along the third direction Z to the projection area S1 of the first connecting piece 102 along the third direction Z, the soldering area of the second connecting piece 14 is increased while avoiding the size of the second connecting piece 14 being too large, affecting the layout of the electrode structure, and causing material waste.

[0091] Optionally, as shown in FIG. 1, the solar cell further comprises a third connecting piece 15 extending along the first direction X and connected with the at least one first busbar 11, and the third connecting piece 15 is closer to the edge of the cell substrate 20 than the second connecting piece 14.

[0092] In some embodiments, one end of the third connecting piece 15 is connected with the second connecting piece 14, and the other end extends towards the edge of the cell substrate 20, so as to utilize the third connecting piece 15 to electrically connect with the first busbar 11 at the edge of the cell substrate 20, thereby collecting the current generated by the first busbar 11 at the edge of the cell substrate 20.

[0093] In some embodiments, as shown in FIG. 1, the battery substrate 20 has two side edge regions arranged oppositely along the second direction Y, and at least one side edge region is provided with a connecting line 16 electrically connecting the ends of the first grid lines 11 of the same polarity. By connecting the ends of the first grid lines 11 of the same polarity through the connecting line 16, the current conduction distance at the edge position of the battery substrate 20 can be shortened, thereby improving the current collection capability of the edge region of the battery substrate 20. In addition, an electrical performance test point can also be provided at the connecting line, and optionally, the test point can have a size larger than that of the connecting line.

[0094] In some embodiments, the connecting line 16 is electrically insulated from the ends of the first grid lines 11 of different polarity. Optionally, the electrical insulation manner includes but is not limited to: providing an insulating layer between the connecting line 16 and the first grid lines 11; or, the connecting line 16 is not in contact with the first grid lines 11 of different polarity, and has a certain spacing.

[0095] Optionally, the present application also provides a photovoltaic module comprising the solar cell in the above embodiments.

[0096] In some embodiments, the photovoltaic module comprises the solar cell, and a plurality of first grid lines 11 are arranged alternately along the first direction X on at least one side of the battery substrate 20, and the first grid lines 11 comprise a plurality of first grid line bodies 101 arranged at intervals, and a first connecting member 102 is arranged at the gap 103 between the adjacent two first grid line bodies 101. In this way, the first connecting member 102 can be connected with the solder strip, and the current collected by the first grid line body 101 can be converged to the solder strip through the first connecting member 102 and led out by the solder strip.

[0097] Further, by arranging the length S of the gap 103 along the second direction Y to be less than or equal to 2 times the interval D between the adjacent two first grid lines 11, the carriers at the gap 103 between the two first grid line bodies 101 can be effectively collected by the first grid line bodies 101 on both sides, while the welding strength of the first connecting member 102 and the solder strip can be ensured. In addition, the amount of paste used to prepare the first grid line body 101 can also be saved.

[0098] Optionally, as shown in FIG. 4, the present application also provides a method for preparing the solar cell in the above embodiments, and the specific steps include:

[0099] Step 101, printing a plurality of first grid lines 11 arranged at intervals on at least one side of the battery substrate 20, the first grid lines 11 comprising a plurality of first grid line bodies 101 arranged at intervals, and a gap 103 is present between the adjacent two first grid line bodies 101.

[0100] Specifically, the screen printing technology can be used to print the slurry on the battery substrate 20 to obtain a plurality of first grid lines 11 arranged at intervals along the first direction X. Each first grid line 11 includes a plurality of first grid line bodies 101 arranged at intervals along the second direction Y, and a gap 103 between adjacent two first grid line bodies 101.

[0101] The printed slurry is solidified and shaped by low-temperature drying at 300-400 degrees to ensure that the first grid line bodies 101 are not deformed or damaged when the first connecting pieces 102 are printed in the next step. The slurry of the first grid line bodies 101 can be selected from the slurry used for printing the auxiliary grid in the related art, and specific reference can be made to the related art, which will not be described here.

[0102] In step 102, a plurality of first connecting pieces 102 are printed at intervals to cover the gaps 103.

[0103] Specifically, the screen printing technology can be used to print the slurry on the battery substrate 20 to obtain a plurality of first connecting pieces 102 arranged at intervals, so that the first connecting pieces 102 cover the gaps 103.

[0104] Further, the first grid line bodies 101 and the first connecting pieces 102 are simultaneously sintered at a high temperature of 700-800 degrees, so that the first grid line bodies 101 and the first connecting pieces 102 are fused and contact each other to form the first grid lines 11, and the first grid line bodies 101 penetrate the passivation layer on the surface of the battery substrate 20 and are connected to the crystalline silicon layer to form a good ohmic contact. After high-temperature sintering, the first connecting pieces 102 can withstand greater tension and have higher welding stability.

[0105] It should be noted that the screen printing patterns for printing the first grid line bodies 101 and the first connecting pieces 102 can be designed according to actual needs. The printing order can also be adjusted as needed, for example, the first connecting pieces 102 can be printed first, and then the first grid line bodies 101 can be printed, which is not limited here.

[0106] In some embodiments, the first grid line bodies 101 and the first connecting pieces 102 can be prepared by step-by-step printing, which not only facilitates actual processing, but also saves the amount of slurry required for preparing the grid lines, ensures the continuity of the grid lines, and improves the current collection capability.

[0107] In some embodiments, in step 101, the second grid line 12 and the third grid line 13 can be printed simultaneously while the first grid line 11 is printed.

[0108] Further, in step 102, the second connecting piece 14 and the third connecting piece 15 can be printed simultaneously while the first connecting piece 102 is printed.

[0109] Of course, the second gate line 12 and the third gate line 13 can also be prepared after step 101, and the second connecting member 14 and the third connecting member 15 can also be prepared after step 102, which can be set according to actual process design needs, and the embodiments of the present application are not limited herein.

[0110] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0111] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A solar cell, characterized by, The battery substrate is provided with a plurality of first grid lines arranged alternately along a first direction on at least one side of the battery substrate, the first grid lines comprising a plurality of first grid line bodies and a plurality of first connecting pieces; the first grid line bodies are arranged at intervals along a second direction, the second direction being perpendicular to the first direction; a gap is provided between adjacent two first grid line bodies; the first connecting pieces are arranged at the gaps between adjacent two first grid line bodies; wherein the distance between adjacent two first grid lines is D, the length of the gap along the second direction is S, and 0 The length of the first connecting piece along the second direction is L, and D≤S≤L-400μm is satisfied; 2. The solar cell according to claim 1, characterized in that, And / or, the distance D between adjacent two first grid lines satisfies 210μm≤D≤1000μm; And / or, the first connecting piece and the first grid line body are at least partially overlapped, and the length d of the overlapping part of the first connecting piece and the first grid line body along the second direction satisfies 0 And / or, the width of the first connecting piece along the first direction is W, and the length of the first connecting piece along the second direction is L, and 1.4≤L / W≤5 is satisfied; And / or, the width of the first connecting piece along the first direction is W, and 210μm≤W≤1200μm is satisfied. The second connecting piece is further included, and the second connecting piece is connected with at least one first grid line, wherein the projection area of the second connecting piece along a third direction is greater than the projection area of the first connecting piece along the third direction, and the third direction is perpendicular to the first direction and the second direction respectively.

3. The solar cell according to claim 2, characterized in that, The projection area of the first connecting piece along the third direction is S1, the projection area of the second connecting piece along the third direction is S2, and 1.1≤S2 / S1≤1.5 is satisfied.

4. The solar cell according to claim 3, characterized in that, The third connecting piece is further included, and the third connecting piece extends along the first direction and is connected with at least one first grid line; the third connecting piece is closer to the edge of the battery substrate than the second connecting piece.

5. The solar cell according to claim 3, wherein Along the first direction, the width of the first connecting piece is greater than the width of the first grid line body; and / or, the first grid lines on the same side of the battery substrate have two conductive types with opposite conductive types; and along the first direction, the first connecting pieces in the first grid lines of the same conductive type are correspondingly arranged, and the first connecting pieces in the first grid lines of different conductive types are staggered with each other.

6. The solar cell according to any one of claims 1 to 5, wherein The maximum height H of the first connecting piece along the third direction satisfies 3μm≤H≤5μm, and the third direction is perpendicular to the first direction and the second direction respectively; and / or, 7. The solar cell according to any one of claims 1 to 5, wherein The side surface of the first connecting piece away from the battery substrate is curved, and the curved surface is recessed from the periphery edge to the center. The battery substrate has two side edge regions arranged oppositely along the second direction, and at least one side edge region is provided with a connecting line, and the connecting line electrically connects the end portions of the first grid lines with the same polarity.

8. The solar cell according to any one of claims 1 to 5, wherein ​ 9. The solar cell according to any one of claims 1 to 5, wherein The first connecting member covers the gap; or the first grid line body at least partially overlaps the first connecting member.

10. A photovoltaic module, characterized by, A solar cell comprising any one of claims 1-9.

11. A method of manufacturing a solar cell as claimed in any one of claims 1-9, characterized in that, The method comprises: Printing a plurality of first grid lines on at least one side of a battery substrate, the first grid lines comprising a plurality of first grid line bodies, and a gap between adjacent two first grid line bodies; Printing a plurality of first connecting members, so that the first connecting members cover the gaps.

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