Photovoltaic cell connecting structure, method for manufacturing the connecting structure, and photovoltaic cell

Abstract

The embodiment of the application provides a photovoltaic cell connecting structure, a preparation method of the connecting structure and a photovoltaic cell, relates to the technical field of photovoltaic cells, and is used for solving the problem of cell piece hidden cracks caused by a traditional welding process in the related art; the photovoltaic cell connecting structure comprises at least two cell pieces, a conductive connecting piece and a solidification layer, the surface of the cell piece is provided with a plurality of metal contact points, the plurality of metal contact points are spaced apart and arranged in a linear array; the conductive connecting piece is used for connecting the at least two cell pieces, the conductive connecting piece is a three-layer stacked structure, and comprises an elastic layer, an intermediate buffer layer and a conductive metal layer which are sequentially and layer by layer arranged, the contact surface of the conductive metal layer and the metal contact point is a welding area, and the welding temperature is lower than 150 DEG C; and the solidification layer is arranged between the conductive metal layer and the metal contact point, so as to pre-fix the welding area, and realize a cell piece connecting structure with low-temperature, no external force or low-stress contact.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and in particular to a photovoltaic cell connection structure, a method for preparing the connection structure, and a photovoltaic cell. Background Technology

[0002] As the core component of solar power generation systems, photovoltaic modules are widely used in ground-mounted photovoltaic power stations, rooftop distributed power generation, agricultural photovoltaics, building-integrated photovoltaics, and other fields. In photovoltaic modules, the main grid lines of the cells are connected in series by solder ribbons. The welding method mainly relies on infrared heating or hot air welding. Specifically, the solder ribbons are coated with flux and then come into contact with the silver paste grid lines on the surface of the cells. They are then heated to 300-400°C using infrared or hot air to form a solid-phase or liquid-phase diffusion connection between the solder ribbons and the silver paste, forming a mechanical-electrical dual connection. The welded cell array is then encapsulated into a module through a lamination process.

[0003] However, the thermal expansion coefficients of the solder ribbon material and the silicon solar cell are significantly different. During the cooling process after welding, the shrinkage of the solder ribbon is much greater than that of the silicon wafer, causing the solar cell to be subjected to bending stress, which can easily lead to microcracks. Moreover, after welding, the solder ribbon and the solar cell form a rigid connection. During the thermal cycling of the module lamination and service life, the difference in thermal expansion between the solder ribbon and the solar cell will continue to generate stress. Under long-term action, this may cause the propagation of microcracks in the solar cell, reduce the power output of the module and shorten its lifespan. Summary of the Invention

[0004] This application provides a photovoltaic cell connection structure, a method for preparing the connection structure, and a photovoltaic cell, which solves the problem of microcracks in photovoltaic modules caused by traditional welding processes in related technologies.

[0005] In a first aspect, embodiments of this application provide a photovoltaic cell connection structure, comprising: at least two cells, each cell having a plurality of metal contact points on its surface, the plurality of metal contact points being spaced apart and arranged in a linear array; a conductive connector for connecting at least two cells, the conductive connector being a three-layer stacked structure, comprising an elastic layer, an intermediate buffer layer, and a conductive metal layer stacked sequentially, the contact surface between the conductive metal layer and the metal contact points being a welding area, the welding temperature being below 150°C; and a curing layer disposed between the conductive metal layer and the metal contact points to pre-fix the welding area.

[0006] Replacing the entire continuous main busbar with multiple dispersed metal contact points reduces the actual welding area and stress concentration areas, thereby reducing the thermal stress transmission path and significantly lowering the risk of overall cell deformation, warping, and cracking. Simultaneously, the welding temperature is below 150℃, constituting low-temperature welding. This results in a small overall temperature rise for the conductive connectors and the cell, significantly reducing the difference in deformation caused by heating. The compressive and tensile forces caused by the incoordination of deformation between materials are greatly weakened, thus significantly reducing bending stress in the cell due to thermal expansion differences and preventing damage such as microcracks and warping. The elastic layer possesses excellent flexibility and resilience, absorbing displacement caused by thermal expansion differences during cooling after welding. This prevents stress from acting directly on the cell and avoids microcracks caused by rigid connections. During subsequent lamination and encapsulation, the elastic layer is further compressed to maintain contact pressure. During service, the tensile / compressive stress generated by thermal cycling is absorbed by the elastic layer instead of being directly transmitted to the silicon substrate, reducing bending stress and microcrack rate in the cell. The intermediate buffer layer provides a conductive path and buffers shear stress, preventing the propagation of microcracks in the solar cells and thus improving the long-term reliability of the module. A curing layer is used at the contact points between the conductive metal layer and the metal contact points for pre-positioning and bonding, ensuring a stress-free bond and avoiding mechanical stress caused by external forces.

[0007] In one possible implementation, the welding heat field is concentrated and confined within the conductive metal layer.

[0008] This means that selective local heating, such as laser welding or induction welding, is used during welding to concentrate heat on the welding area, melting only the low-melting-point conductive metal layer while leaving other layers of the conductive connector unaffected. This ensures that the entire conductive connector and the entire battery cell remain at a low temperature of less than 150°C, preventing overall temperature rise and further preventing damage such as microcracks and warping of the battery cell.

[0009] In one possible implementation, the elastic layer is configured to abut against the encapsulation layer of the photovoltaic cell.

[0010] After welding and cooling to room temperature, the encapsulation layer is further compressed by the lamination process. The elastic layer continues to hold the contact surface against the elastic layer by its rebound force, maintaining the contact pressure. The elastic layer can also continuously absorb the repeated deformation stress brought about by subsequent use, ensuring long-term durability, no cracking, and no desoldering. It also allows the tensile / compressive stress generated by thermal cycling during service to be absorbed by the elastic layer, preventing it from being transmitted to the battery cells.

[0011] In one possible implementation, the conductive metal layer is made of a low-melting-point alloy with a melting point below 150°C; and / or, the elastic layer is made of a conductive flexible elastic material or the elastic layer is an array of micro-elastic spring structures; and / or, the intermediate buffer layer is a porous mesh structure formed by micron-scale metal fibers or ultrathin metal foils.

[0012] The conductive metal layer is made of a low-melting-point alloy with a melting point below 150°C. This allows the conductive metal layer to melt and form a metallic connection with multiple metal contact points. Low-temperature welding technology, combined with the use of low-melting-point alloys instead of flux, completely avoids residual corrosion problems, improving the long-term reliability of the module in humid, hot, and salt spray environments. The elastic layer is directly made of conductive flexible elastic material, ensuring strong overall fit, no gaps, and uniform stress distribution, preventing localized pressure. It also possesses inherent conductivity, ensuring smooth current transmission. The arrayed micro-elastic spring structure has a large deformation margin, can withstand large temperature differences and significant thermal displacements, exhibits excellent resistance to deformation and fatigue, and is not prone to failure over long-term use. Furthermore, the gaps between the springs allow for smooth airflow, quickly dissipating welding residual heat and module operating heat, reducing high-temperature damage to the solar cells. The porous mesh structure obtained by interweaving and overlapping the aforementioned micron-level metal fibers has good toughness, allowing for free bending and deformation, perfectly offsetting the shear dislocation stress caused by welding and temperature differences, and is not prone to brittleness. The porous mesh structure obtained by opening and stretching ultra-thin metal foil has a dense metal foil substrate, lower conduction resistance, less loss in large current transmission, and higher electrical conduction efficiency; moreover, the foil substrate has strong integrity, outstanding compressive and tensile strength, can withstand greater extrusion and external force, and has strong structural stability.

[0013] In one possible implementation, the outline shape of the metal contact point is circular, elliptical, or oval.

[0014] Circular, elliptical, and oval shapes all have smooth contours without sharp corners, which can effectively reduce local stress concentration caused by differences in thermal expansion coefficients during welding. Oval and elliptical shapes have a longer contact length in a certain direction, allowing conductive connectors welded to metal contact points to have a greater tolerance for positional deviation in that direction, which helps reduce the risk of incomplete or missing welds due to slight offsets.

[0015] In one possible implementation, the area of ​​a single metal contact point is 0.1-1 mm²; and / or, the distance between two adjacent metal contact points is 1-3 times the diameter of a single metal contact point; and / or, the height of the metal contact point is 20-30 μm.

[0016] The area range of 0.1-1 mm² achieves an optimized balance between low light shading and low contact resistance, while also taking into account photoelectric conversion efficiency and current conduction performance.

[0017] In one possible implementation, the cured layer is a photocurable adhesive layer or a thermocurable adhesive layer.

[0018] The UV-curable adhesive layer cures rapidly during the pre-curing stage via UV irradiation, eliminating the need for high-temperature or solvent cleaning and directly achieving zero-stress bonding between the conductive metal layer and the metal contact points. Thermo-curable adhesive layers achieve low-stress pre-curing, providing firm positioning, good toughness, and resistance to high temperatures and temperature changes.

[0019] In one possible implementation, the coverage area of ​​the cured layer is greater than or equal to the coverage area of ​​the plurality of metal contact points.

[0020] It forms a full-area coverage and limit for the contact area, maintaining a flat and fit throughout, without localized curling or gaps, and eliminating localized stress concentration.

[0021] In one possible implementation, the welding time is 0.1-2 seconds per weld point.

[0022] Using short-time rapid welding of 0.1-2 seconds per weld point can effectively reduce the heat-affected zone, reduce temperature rise and thermal deformation, ensure uniform and stable weld fusion, reduce incomplete welds, and significantly improve welding production efficiency and reduce energy consumption.

[0023] Secondly, embodiments of this application provide a method for fabricating a photovoltaic cell connection structure, used to fabricate the photovoltaic cell connection structure described above, comprising:

[0024] Multiple metal contact points are provided on the surface of at least two battery cells, and the multiple metal contact points are spaced apart and arranged in a linear array.

[0025] A photocurable adhesive layer or a thermocurable adhesive layer is applied to the metal contact point;

[0026] A conductive connector is provided, the conductive connector having a three-layer stacked structure, including an elastic layer, an intermediate buffer layer and a conductive metal layer stacked sequentially;

[0027] The conductive connector is placed over the metal contact point, and the conductive metal layer is in contact with the metal contact point. The contact surface between the conductive metal layer and the metal contact point is the welding area.

[0028] Curing of the photocurable adhesive layer or the thermocurable adhesive layer;

[0029] The conductive metal layer and the metal contact point are welded by laser welding or induction welding to form a conductive metal connection, and the welding temperature is below 150°C.

[0030] After cooling to room temperature, the elastic layer is compressed using a lamination process.

[0031] Thirdly, embodiments of this application provide a photovoltaic cell, which includes the photovoltaic cell connection structure described above. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0033] Figure 1 This is a schematic diagram of the structure of the conductive connector connecting two battery cells provided in an embodiment of this application;

[0034] Figure 2 A schematic diagram showing a battery cell with multiple metal contact points on its front or back side as provided in an embodiment of this application;

[0035] Figure 3 This is a schematic diagram of the structure of a conductive connector with a three-layer stacked structure provided in an embodiment of this application;

[0036] Figure 4 A schematic diagram showing the thickness comparison of the conductive connectors before and after compression using a lamination process in the photovoltaic cell connection structure provided in this application embodiment;

[0037] Figure 5 A flowchart illustrating the fabrication method of the photovoltaic cell connection structure provided in this application embodiment.

[0038] Figure label:

[0039] 100-cell battery;

[0040] 101 - Metal contact point; 102 - Anti-reflection passivation composite layer; 103 - Main gate line;

[0041] 200 - Conductive connector;

[0042] 201 - Elastic layer; 202 - Intermediate buffer layer; 203 - Conductive metal layer;

[0043] 300 - Curing layer.

[0044] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0045] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0046] refer to Figure 1 , Figure 2 and Figure 3 This application provides a photovoltaic cell connection structure, which includes at least two cells 100, a conductive connector 200, and a curing layer 300.

[0047] The solar cell 100 is a crystalline silicon solar cell. The surface of the solar cell 100, that is, the front and / or the back, is provided with a plurality of metal contact points 101 made of silver or silver alloy. The plurality of metal contact points 101 protrude from the surface of the solar cell 100. The plurality of metal contact points 101 are spaced apart and arranged in a linear array, which has good conductivity and solderability.

[0048] An anti-reflection passivation composite layer 102 is also formed on the silicon substrate surface of the solar cell 100 to reduce solar reflection loss, improve light absorption utilization, passivate silicon wafer surface defects, suppress carrier recombination loss, and significantly improve the photovoltaic cell's photoelectric conversion efficiency and long-term stability. Multiple metal contact points 101 are disposed on the surface of the solar cell 100 on which the anti-reflection passivation composite layer 102 is formed.

[0049] At least two solar cells 100 are arranged adjacent to each other, and a conductive connector 200 is used to electrically connect the at least two solar cells 100.

[0050] The conductive connector 200 is strip-shaped and spans between two adjacent battery cells 100. One end of the conductive connector 200 is connected to multiple metal contact points 101 of one of the battery cells 100, and the other end is connected to multiple metal contact points 101 of the other battery cell 100 to achieve electrical connection between the two adjacent battery cells 100.

[0051] The conductive connector 200 has a three-layer stacked structure, including an elastic layer 201, an intermediate buffer layer 202 and a conductive metal layer 203 stacked from top to bottom. The conductive metal layer 203 is located at the bottom layer, the elastic layer 201 is located at the top layer, and the intermediate buffer layer 202 is located between the elastic layer 201 and the conductive metal layer 203.

[0052] The conductive metal layer 203 is in contact with multiple metal contact points 101, and the contact surface between the conductive metal layer 203 and the multiple metal contact points 101 is a welding area. Under the welding process, it will melt with the multiple metal contact points 101 to form a reliable metal conductive connection.

[0053] Replacing the entire continuous main grid line 103 with multiple dispersed metal contact points 101 reduces the actual welding area and stress concentration areas, thereby reducing the thermal stress transmission path and significantly reducing the risk of overall deformation, warping, and cracking of the battery cell 100.

[0054] Meanwhile, the welding temperature is below 150℃, which is low-temperature welding. The overall temperature rise of the conductive connector 200 and the battery cell 100 is small, and the difference in deformation caused by the heating of various materials is significantly reduced. The squeezing and tensile forces caused by the incoordination of deformation between materials are greatly weakened, thereby significantly reducing the bending stress of the battery cell 100 caused by the difference in thermal expansion and avoiding damage problems such as microcracks and warping of the battery cell 100.

[0055] During welding, the welding heat field is concentrated and confined to the conductive metal layer 203.

[0056] This means that selective local heating, such as laser welding or induction welding, is used during welding to concentrate heat on the welding area, so that only the low-melting-point conductive metal layer 203 melts, while the other layers of the conductive connector 200 are not affected. This ensures that the conductive connector 200 and the battery cell 100 as a whole are kept at a low temperature of less than 150°C, avoiding overall temperature rise and further preventing damage problems such as microcracks and warping of the battery cell.

[0057] The conductive metal layer 203 is made of a low-melting-point alloy with a melting point below 150°C. The conductive metal layer 203 is melted and forms a metal connection with multiple metal contact points 101. Low-temperature welding technology is used in combination with low-melting-point alloy to replace flux, which completely avoids the problem of residual corrosion and improves the long-term reliability of the component in humid and hot and salt spray environments.

[0058] The conductive metal layer 203 can be made of SnBi alloy or Sn35BiAg alloy.

[0059] The welding time is 0.1-2 seconds per weld point.

[0060] Using short-time rapid welding of 0.1-2 seconds per weld point can effectively reduce the heat-affected zone, reduce temperature rise and thermal deformation, ensure uniform and stable weld fusion, reduce incomplete welds, and significantly improve welding production efficiency and reduce energy consumption.

[0061] The elastic layer 201 possesses excellent flexibility and resilience. During welding, the elastic layer 201 is pre-compressed and maintains zero-stress contact, absorbing displacement caused by thermal expansion differences during cooling after welding. This prevents stress from acting directly on the solar cell 100 and avoids microcracks in the solar cell 100 due to rigid connections. During subsequent lamination and encapsulation, the elastic layer 201 is further compressed to maintain contact pressure. During service, the tensile / compressive stress generated by thermal cycling is absorbed by the elastic layer 201 rather than being directly transferred to the silicon substrate, reducing the bending stress and microcrack rate of the solar cell 100.

[0062] The elastic layer 201 is configured to abut against the encapsulation layer of the photovoltaic cell.

[0063] refer to Figure 4 After welding and cooling to room temperature, the encapsulation layer is further compressed by the lamination process to compress the elastic layer 201. The elastic layer 201 continuously holds the contact surface against the elastic force to maintain the contact pressure. The elastic layer 201 can also continuously absorb the repeated deformation stress brought about by subsequent use to ensure long-term durability, no cracking, and no desoldering. It also allows the tensile / compressive stress generated by thermal cycling during service to be absorbed by the elastic layer and prevented from being transmitted to the battery cell.

[0064] The elastic layer 201 is made of a conductive flexible elastic material or is an array of miniature elastic spring structures.

[0065] The elastic layer 201 is made directly from conductive flexible elastic material, which has strong overall fit, no gaps, uniform force distribution, and no local pressure; and the body itself has conductive properties, so the current transmission is smooth.

[0066] The elastic layer 201 can be made of conductive silicone rubber.

[0067] The array of miniature elastic springs has a large deformation margin, can withstand large temperature differences and large thermal displacements, and has excellent resistance to deformation and fatigue, making it less prone to failure after long-term use. In addition, the gaps between the springs allow for smooth air circulation, which can quickly dissipate welding residual heat and module working heat, reducing the damage of high temperature to the solar cells.

[0068] The intermediate buffer layer 202 can provide a conductive path and buffer shear stress, preventing the propagation of microcracks in the solar cell 100, thereby improving the long-term reliability of the module.

[0069] The intermediate buffer layer 202 is a porous mesh structure made of micron-sized metal fibers or ultrathin metal foil.

[0070] Micron-sized metal fibers are slender, long filamentous metal substrates made from metal raw materials through drawing and processing. They have a single filament diameter within the micron range and exhibit good flexibility and excellent thermal and electrical conductivity. Ultrathin metal foils are sheet-like metal materials made from metal raw materials through rolling, calendering, and other processes. They are extremely thin, lightweight, uniform in thickness, and possess good ductility.

[0071] The porous mesh structure obtained by interlacing and overlapping the aforementioned micron-sized metal fibers exhibits excellent toughness, allowing for free bending and deformation. This perfectly offsets the shear stress caused by welding and temperature differences, preventing brittleness. The porous mesh structure obtained by opening and stretching ultra-thin metal foil has a dense metal foil substrate, resulting in lower conductivity, less current transmission loss, and higher electrical conductivity. Furthermore, the foil substrate boasts strong integrity, outstanding compressive and tensile strength, and can withstand significant extrusion and external forces, demonstrating high structural stability.

[0072] The curing layer 300 is disposed between the conductive metal layer 203 and the metal contact point 101 to pre-fix the welding area.

[0073] A curing layer 300 is used to pre-position and bond the conductive metal layer 203 and the metal contact point 101 at the contact point, so that the two are in a stress-free bonding state and avoid mechanical stress caused by external force.

[0074] Among them, the curing layer 300 is a light-curing adhesive layer or a heat-curing adhesive layer.

[0075] The UV-curable adhesive layer cures rapidly during the pre-curing stage via UV irradiation, eliminating the need for high-temperature or solvent cleaning and directly achieving zero-stress bonding between the conductive metal layer 203 and the metal contact point 101. The thermosetting adhesive layer enables low-stress pre-curing, providing firm positioning, good toughness, and resistance to high temperatures and temperature changes.

[0076] In this embodiment, the coverage area of ​​the cured layer 300 is greater than or equal to the coverage area of ​​the plurality of metal contact points 101.

[0077] It forms a full-area coverage and limit for the contact area, maintaining a flat and fit throughout, without localized curling or gaps, and eliminating localized stress concentration.

[0078] In this embodiment, the outline shape of the metal contact point 101 is circular, elliptical, or oval.

[0079] The outline shape refers to the outermost shape of the metal contact point 101 when viewed from directly above; the oval shape refers to a semi-circular shape at both ends and a straight edge in the middle, similar to the shape of a racetrack.

[0080] Circular, elliptical, and oval shapes all have smooth contours without sharp corners, which can effectively reduce local stress concentration caused by differences in thermal expansion coefficients during welding. Oval and elliptical shapes have a longer contact length in a certain direction, which allows the conductive connector 200 welded to the metal contact point 101 to have a greater tolerance for positional deviation in that direction, which helps to reduce the risk of poor welding or missing welding due to slight offset.

[0081] In this embodiment of the application, the area of ​​a single metal contact point 101 is 0.1-1 mm².

[0082] The area range of 0.1-1 mm² achieves an optimized balance between low light shading and low contact resistance, while also taking into account photoelectric conversion efficiency and current conduction performance.

[0083] When the area is less than 0.1 mm², the welding area is small, the welding reliability decreases, and it is easy to have a poor weld or detachment. When the area is greater than 1 mm², although it can reduce the contact resistance and enhance the weld strength, it will increase the light-blocking area, reduce the effective light-receiving area of ​​the solar cell, and ultimately reduce the power generation efficiency.

[0084] The distance between two adjacent metal contact points 101 is 1 to 3 times the diameter of a single metal contact point 101.

[0085] The height of the metal contact point 101 is 20-30 μm.

[0086] refer to Figure 5 This application also provides a method for fabricating a photovoltaic cell connection structure, used to fabricate the photovoltaic cell connection structure described above, comprising:

[0087] Step S1: Multiple metal contact points 101 are provided on the surface of at least two battery cells 100, and the multiple metal contact points 101 are spaced apart and arranged in a linear array.

[0088] Step S2: Apply a light-curing adhesive layer or a heat-curing adhesive layer to the metal contact point 101.

[0089] Step S3: Provide a conductive connector 200, which is a three-layer stacked structure, including an elastic layer 201, an intermediate buffer layer 202 and a conductive metal layer 203 stacked in sequence.

[0090] Step S4: Cover the metal contact point 101 with the conductive connector 200, and make the conductive metal layer 203 contact the metal contact point 101. The contact surface between the conductive metal layer 203 and the metal contact point 101 is the welding area.

[0091] Step S5: Cure the light-curing adhesive layer or the heat-curing adhesive layer.

[0092] Step S6: Weld the conductive metal layer 203 to the metal contact point 101 using laser welding or induction welding to form a conductive metal connection. The welding temperature is below 150°C.

[0093] Step S7: After cooling to room temperature, compress the elastic layer 201 through a lamination process.

[0094] The above method will be described in detail below through specific embodiments:

[0095] refer to Figure 2 Two adjacent solar cells 100 are provided. The size of the solar cell 100 is 156mm×156mm. The traditional continuous main grid line 103 is replaced by several circular or elliptical metal contact points 101 with a diameter of 0.8mm, which are arranged linearly. The spacing between the metal contact points 101 is 2-3mm.

[0096] refer to Figure 1 A conductive connector 200 is placed above two adjacent battery cells 100. One end of the conductive connector 200 overlaps the left battery cell, and the other end of the conductive connector 200 crosses the gap between the two adjacent battery cells 100 and overlaps the right battery cell.

[0097] refer to Figure 2 The conductive connector 200 covers the entire row of contact points, and the coverage area of ​​the conductive connector 200 is represented by a dashed rectangle in the figure.

[0098] refer to Figure 3 The conductive connector 200 includes an elastic layer 201, an intermediate buffer layer 202, and a conductive metal layer 203 stacked sequentially. The conductive metal layer 203 is made of SnBi alloy with a melting point of 138°C and a thickness of 20 μm. The intermediate buffer layer 202 is a metal fiber woven mesh or a porous metal foil with a thickness of 50 μm. The elastic layer 201 is conductive silicone rubber or a micro-spring array with a thickness of 100 μm.

[0099] refer to Figure 1 UV adhesive or thermosetting adhesive is provided at the contact position of the conductive connector 200 and the metal contact point 101 of the two adjacent battery cells 100.

[0100] Before welding, UV adhesive or thermosetting adhesive is cured to pre-fix the contact position of the conductive connector 200 and the metal contact points 101 of two adjacent battery cells 100.

[0101] The conductive metal layer 203 is welded to the metal contact point 101 by laser welding or induction welding to form a conductive metal connection, and the welding temperature is below 150℃.

[0102] After cooling to room temperature, the elastic layer 201 is compressed through a lamination process.

[0103] refer to Figure 4 Before welding, the thickness of the conductive connector 200 on the left is H1, and there is a tiny gap (or just enough contact) between it and the battery cell 100. After welding and lamination, the conductive connector 200 on the right is compressed, and its thickness becomes H2.

[0104] This application also provides a photovoltaic cell, which includes the photovoltaic cell connection structure described above.

[0105] In summary, this application provides a photovoltaic cell connection structure, a method for preparing the connection structure, and a photovoltaic cell. The photovoltaic cell connection structure includes: at least two cells 100, with multiple metal contact points 101 arranged at intervals on the surface of each cell 100; a conductive connector 200 for connecting the at least two cells 100, the conductive connector 200 being a three-layer stacked structure, including an elastic layer 201, an intermediate buffer layer 202, and a conductive metal layer 203 stacked sequentially, the contact surface between the conductive metal layer 203 and the metal contact points 101 being a welding area, the welding temperature being below 150°C; and a curing layer 300 disposed between the conductive metal layer 203 and the metal contact points 101 to pre-fix the welding area.

[0106] Replacing the entire continuous main grid line 103 with multiple dispersed metal contact points 101 reduces the actual welding area and stress concentration areas, thereby reducing the thermal stress transmission path and significantly reducing the risk of overall deformation, warping, and cracking of the battery cell 100.

[0107] Meanwhile, the welding temperature is below 150℃, which is low-temperature welding. The overall temperature rise of the conductive connector 200 and the battery cell 100 is small, and the difference in deformation caused by the heating of various materials is significantly reduced. The squeezing and tensile forces caused by the incoordination of deformation between materials are greatly weakened, thereby significantly reducing the bending stress of the battery cell 100 caused by the difference in thermal expansion and avoiding damage problems such as microcracks and warping of the battery cell 100.

[0108] ​Furthermore, the elastic layer 201 possesses excellent flexibility and resilience. During welding, the elastic layer 201 is pre-compressed and maintains zero-stress contact, absorbing displacement caused by thermal expansion differences during post-weld cooling. This prevents stress from acting directly on the solar cell 100, thus preventing microcracks from forming in the solar cell 100 due to rigid connections. During subsequent lamination and encapsulation, the elastic layer 201 is further compressed to maintain contact pressure. During service, the tensile / compressive stress generated by thermal cycling is absorbed by the elastic layer 201 rather than being directly transferred to the silicon substrate, reducing the bending stress and microcrack rate of the solar cell 100. The intermediate buffer layer 202 provides a conductive path and buffers shear stress, preventing the propagation of microcracks in the solar cell 100, thereby improving the long-term reliability of the module.

[0109] Finally, a curing layer 300 is used to pre-position and bond the conductive metal layer 203 and the metal contact point 101 at the contact point, so that the two are in a stress-free bonding state and avoid mechanical stress caused by external force.

[0110] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A photovoltaic cell connection structure, characterized in that, include: At least two battery cells (100), the surface of which is provided with a plurality of metal contact points (101), the plurality of metal contact points (101) being spaced apart and arranged in a linear array; A conductive connector (200) is used to connect at least two of the battery cells (100). The conductive connector (200) has a three-layer stacked structure, including an elastic layer (201), an intermediate buffer layer (202), and a conductive metal layer (203) stacked in sequence. The contact surface between the conductive metal layer (203) and the metal contact point (101) is a welding area, and the welding temperature is below 150°C. A curing layer (300) is disposed between the conductive metal layer (203) and the metal contact point (101) to pre-fix the welding area.

2. The photovoltaic cell connection structure according to claim 1, characterized in that, The welding heat field is concentrated and confined within the conductive metal layer (203).

3. The photovoltaic cell connection structure according to claim 1, characterized in that, The elastic layer (201) is configured to abut against the encapsulation layer of the photovoltaic cell.

4. The photovoltaic cell connection structure according to claim 1, characterized in that, The conductive metal layer (203) is made of a low-melting-point alloy with a melting point below 150°C; and / or, The elastic layer (201) is made of a conductive flexible elastic material or the elastic layer (201) is an array of micro-elastic spring structures; and / or, The intermediate buffer layer (202) is a porous mesh structure made of micron-sized metal fibers or ultra-thin metal foil.

5. The photovoltaic cell connection structure according to claim 1, characterized in that, The outline shape of the metal contact point (101) is circular, elliptical or oval.

6. The photovoltaic cell connection structure according to claim 1, characterized in that, The area of ​​a single metal contact point (101) is 0.1-1 mm²; and / or, The distance between two adjacent metal contact points (101) is 1-3 times the diameter of a single metal contact point (101); and / or, The height of the metal contact point (101) is 20-30 μm.

7. The photovoltaic cell connection structure according to claim 1, characterized in that, The cured layer (300) is a light-curing adhesive layer or a thermosetting adhesive layer.

8. The photovoltaic cell connection structure according to claim 1, characterized in that, The coverage area of ​​the cured layer (300) is greater than or equal to the coverage area of ​​the plurality of metal contact points (101).

9. The photovoltaic cell connection structure according to claim 1, characterized in that, The welding time is 0.1-2 seconds per weld point.

10. A method for preparing a photovoltaic cell connection structure, used to manufacture the photovoltaic cell connection structure according to any one of claims 1-9, characterized in that, include: Multiple metal contact points (101) are provided on the surface of at least two battery cells (100), and the multiple metal contact points (101) are spaced apart and arranged in a linear array; A photocurable adhesive layer or a thermocurable adhesive layer is provided on the metal contact point (101); A conductive connector (200) is provided, the conductive connector (200) is a three-layer stacked structure, including an elastic layer (201), an intermediate buffer layer (202) and a conductive metal layer (203) stacked in sequence. The conductive connector (200) is covered over the metal contact point (101), and the conductive metal layer (203) is in contact with the metal contact point (101). The contact surface between the conductive metal layer (203) and the metal contact point (101) is a welding area. Curing of the photocurable adhesive layer or the thermocurable adhesive layer; The conductive metal layer (203) and the metal contact point (101) are welded by laser welding or induction welding to form a conductive metal connection, and the welding temperature is below 150°C. After cooling to room temperature, the elastic layer (201) is compressed by a lamination process.

11. A photovoltaic cell, characterized in that, Includes the photovoltaic cell connection structure as described in any one of claims 1-9.

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